This document discusses the anatomy, embryology, physiology and clinical correlations of the lacrimal apparatus. It describes the different structures that make up the secretory and excretory lacrimal systems including the main and accessory lacrimal glands, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It also explains tear secretion, the components of the tear film, and the lacrimal pump mechanism for drainage. Common clinical conditions associated with different parts of the lacrimal system like dacryocystitis and canaliculitis are also mentioned.
This document summarizes the history and pathogenesis of pathological myopia. It discusses definitions of pathological myopia and classifications of myopia by degree, age of onset, and other factors. Risk factors for pathological myopia include race, age, gender, education level and familial inheritance. Complications include peripheral retinal degenerations which can lead to retinal detachment, myopic foveoschisis, macular holes, lacquer cracks, and choroidal neovascularization. Surgical treatments are discussed for various complications.
This document discusses the anatomy and development of the vitreous humor in the eye. It begins by describing the embryological origin of vitreous cells from surface ectoderm, neuroectoderm, and mesodermal tissues. During the primary vitreous stage, the vitreous body begins forming before closure of the choroidal fissure and appears as a fibrillated secretion filling the vitreous space. The document then covers the general features, structure including hyaloid layers, cortical and medullary regions, attachments, composition and transport processes of the mature vitreous humor. It concludes by describing the physicochemical properties and factors affecting expansion and contraction of the vitreous gel.
Binocular single vision refers to simultaneous vision with two eyes that occurs when an individual fixates on an object. There are three grades of binocular vision: simultaneous perception, fusion, and stereopsis. Fusion is the ability to see a composite picture from two similar images, while stereopsis provides the impression of depth by superimposing images from slightly different angles. Tests for binocular vision include those for simultaneous perception, fusion, and stereopsis using instruments like the synaptophore. Binocular vision develops through infancy and childhood as the visual axes become coordinated to direct each fovea at the object of regard.
Anatomy and physiology of extraocular muscles and applied aspectsReshma Peter
The document discusses the anatomy and physiology of the extraocular muscles. It describes the six extraocular muscles - four rectus muscles (superior, inferior, medial, lateral) and two oblique muscles (superior, inferior). It provides details on the origin, insertion, nerve supply, blood supply, actions and relations of each individual muscle. It also discusses the fascial sheaths and extensions of the muscles, their roles in supporting the eyeball and coordinating eye movements, and some clinical applications regarding surgeries involving the extraocular muscles.
The document summarizes the structure and function of the tear film. It consists of three layers - an outer lipid layer, middle aqueous layer, and inner mucin layer. The lipid layer prevents evaporation and overflow of tears. The aqueous layer hydrates the cornea and contains nutrients. The mucin layer lubricates the eye surface. Tears are produced through basal and reflex secretion and drained through the lacrimal system into the nose. Blinking helps spread and replenish the tear film layers, which must be continuously renewed to maintain a smooth optical surface and protect the cornea.
This document discusses optic disc changes in glaucoma. It defines key terms like optic nerve head and lamina cribrosa. It describes physiological cupping and normal cup-to-disc ratios. Pathogenesis of optic nerve head changes in glaucoma involves mechanical effects of increased intraocular pressure and vascular effects of ischemia. Signs suggestive of glaucoma include increased cup size, asymmetry between eyes, thinning of the neuroretinal rim, notches, splinter hemorrhages, and retinal nerve fiber layer defects preceding other changes. Advanced glaucoma shows total cupping and bending of retinal vessels at the disc margin.
This document provides information on the anatomy and physiology of the cornea. It describes the layers of the cornea including the epithelium, Bowman's membrane, stroma, Dua's layer, Descemet's membrane, and endothelium. It discusses the transparency of the cornea, metabolic processes, drug permeability, wound healing, and the effects of contact lens wear on corneal physiology. The cornea has several specialized functions including refracting light and protecting the interior of the eye.
This document summarizes the history and pathogenesis of pathological myopia. It discusses definitions of pathological myopia and classifications of myopia by degree, age of onset, and other factors. Risk factors for pathological myopia include race, age, gender, education level and familial inheritance. Complications include peripheral retinal degenerations which can lead to retinal detachment, myopic foveoschisis, macular holes, lacquer cracks, and choroidal neovascularization. Surgical treatments are discussed for various complications.
This document discusses the anatomy and development of the vitreous humor in the eye. It begins by describing the embryological origin of vitreous cells from surface ectoderm, neuroectoderm, and mesodermal tissues. During the primary vitreous stage, the vitreous body begins forming before closure of the choroidal fissure and appears as a fibrillated secretion filling the vitreous space. The document then covers the general features, structure including hyaloid layers, cortical and medullary regions, attachments, composition and transport processes of the mature vitreous humor. It concludes by describing the physicochemical properties and factors affecting expansion and contraction of the vitreous gel.
Binocular single vision refers to simultaneous vision with two eyes that occurs when an individual fixates on an object. There are three grades of binocular vision: simultaneous perception, fusion, and stereopsis. Fusion is the ability to see a composite picture from two similar images, while stereopsis provides the impression of depth by superimposing images from slightly different angles. Tests for binocular vision include those for simultaneous perception, fusion, and stereopsis using instruments like the synaptophore. Binocular vision develops through infancy and childhood as the visual axes become coordinated to direct each fovea at the object of regard.
Anatomy and physiology of extraocular muscles and applied aspectsReshma Peter
The document discusses the anatomy and physiology of the extraocular muscles. It describes the six extraocular muscles - four rectus muscles (superior, inferior, medial, lateral) and two oblique muscles (superior, inferior). It provides details on the origin, insertion, nerve supply, blood supply, actions and relations of each individual muscle. It also discusses the fascial sheaths and extensions of the muscles, their roles in supporting the eyeball and coordinating eye movements, and some clinical applications regarding surgeries involving the extraocular muscles.
The document summarizes the structure and function of the tear film. It consists of three layers - an outer lipid layer, middle aqueous layer, and inner mucin layer. The lipid layer prevents evaporation and overflow of tears. The aqueous layer hydrates the cornea and contains nutrients. The mucin layer lubricates the eye surface. Tears are produced through basal and reflex secretion and drained through the lacrimal system into the nose. Blinking helps spread and replenish the tear film layers, which must be continuously renewed to maintain a smooth optical surface and protect the cornea.
This document discusses optic disc changes in glaucoma. It defines key terms like optic nerve head and lamina cribrosa. It describes physiological cupping and normal cup-to-disc ratios. Pathogenesis of optic nerve head changes in glaucoma involves mechanical effects of increased intraocular pressure and vascular effects of ischemia. Signs suggestive of glaucoma include increased cup size, asymmetry between eyes, thinning of the neuroretinal rim, notches, splinter hemorrhages, and retinal nerve fiber layer defects preceding other changes. Advanced glaucoma shows total cupping and bending of retinal vessels at the disc margin.
This document provides information on the anatomy and physiology of the cornea. It describes the layers of the cornea including the epithelium, Bowman's membrane, stroma, Dua's layer, Descemet's membrane, and endothelium. It discusses the transparency of the cornea, metabolic processes, drug permeability, wound healing, and the effects of contact lens wear on corneal physiology. The cornea has several specialized functions including refracting light and protecting the interior of the eye.
This document provides an overview of the anatomy and physiology of the lacrimal system. It describes the secretory apparatus including the lacrimal gland and accessory glands. It then describes the excretory apparatus including the puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It discusses the development of both the secretory and excretory systems. It provides details on the main lacrimal gland, lacrimal ducts, accessory lacrimal glands, lacrimal puncta, and canaliculi. It discusses the arterial supply, venous and lymphatic drainage, and nerve supply to the lacrimal gland. It covers the structure, functions, and applied
The lacrimal apparatus consists of the lacrimal gland, lacrimal drainage system, and associated structures that produce and drain tears from the eye.
The lacrimal gland develops from surface ectoderm and is located above and lateral to the eye. Tears produced by the gland drain through puncta and canaliculi into the lacrimal sac, then through the nasolacrimal duct into the nose.
The lacrimal sac is lodged in the lacrimal fossa of the medial orbital wall. It connects to the nasolacrimal duct, which courses posteriorly and laterally through bone to drain into the nasal cavity. Coordinated blinking and pressure differences aid
The retina is the light-sensitive tissue lining the back of the eye. It contains 10 layers including the retinal pigment epithelium, rods and cones, bipolar and ganglion cells. The retina is thinnest near the center and thickens toward the periphery. Key structures include the optic disc, macula with fovea for sharp central vision, and ora serrata marking the edge. The retina contains over 120 million light receptors and ganglion cells whose axons converge at the optic disc to form the optic nerve.
LIMBUS… • The limbus forms the border between the transparent cornea and opaque sclera, contains the pathways of aqueous humour outflow, and is the site of surgical incisions for cataract and glaucoma
2. Anatomical Limbus: Circumcorneal transitional zone of the conjunctivocorneal & corneoscleral junction Conjunctivo-corneal junction: • Bulbar conjunctiva is firmly adherent to underlying structures • Substantia propria of the conjunctiva stops here but its epithelium continues with that of the cornea. Sclero-corneal junction: • Transparent corneal lamellae become continuous • With the oblique, circular and opaque fibres of sclera
3. CONTINUE…. • In the area near limbus, the conjunctiva, tenon’s capsule & the episcleral tissue are fused into a dense tissue which is strongly adherent to corneo scleral junction.It is preferred site for obtaining a firm hold of the eyeball during ocular surgery. • The limbus is a common site for the occurrence of corneal epithelial neoplasm. • The Limbus contains radially oriented fibrovascular ridge known as the palisades of Vogt that may harbour a stem cell population. The palisades of Vogt are more common in the superior and inferior quadrants around the eye
The eyelids are thin folds of skin that protect the eye. They have three main functions - protection, regulation, and maintenance. The eyelids develop from embryonic processes and have several layers including skin, muscle, orbital fat, and conjunctiva. They are supplied by nerves from the oculomotor, trigeminal, and facial cranial nerves as well as the sympathetic nervous system. The eyelids help to spread tears and protect the eyes.
The optic nerve receives its blood supply from multiple sources along its path from the eye to the brain. In the eye, it is supplied by retinal arterioles and occasionally the ciliary artery. In the prelaminar region, it receives blood from ciliary region vessels and peripapillary choroidal or short posterior ciliary vessels. Deeper regions receive supply from ciliary and retinal circulations, including recurrent pial vessels and branches of the central artery of the retina. In the orbit, it has periaxial vessels from the ophthalmic artery and axial vessels from the central retinal artery. Within the cranium, it is supplied by the pial plexus fed by branches from the ophthalmic artery.
Binocular vision requires two clear eyes that can coordinate focusing on the same object. This allows the brain to fuse the two slightly different retinal images into a single image. There are grades of binocular vision including fusion and stereopsis, which is the ability to perceive depth. For binocular vision to develop, the eyes must maintain proper retinal correspondence and suppression. Tests like the Titmus fly test evaluate stereopsis. Understanding binocular vision and stereopsis is important for diagnosing and treating eye alignment disorders.
The document discusses the anatomy, embryology, and function tests of the macula lutea. It describes the macula lutea as a 5.5mm circular area at the posterior pole of the retina that subserves central vision. It notes the macula's delayed development until 8 months gestation and specialization of the fovea which contains the highest concentration of cones. The document outlines various macular function tests used to evaluate macular diseases, including visual acuity, Amsler grid, microperimetry, and electroretinography. It provides details on the anatomy and cell layers of the fovea centralis and techniques for assessing macular integrity with tests like the Maddox rod.
High myopia, or severe nearsightedness, is defined as a refractive error of -6.00 diopters or worse. It can be caused by genetic factors and environmental factors like extensive near work. Complications of high myopia include retinal detachment, glaucoma, cataracts, and pathological changes to the eye. Management options include spectacle correction, contact lenses, refractive surgery, and orthokeratology, which uses special contact lenses worn overnight to temporarily reshape the cornea and improve uncorrected vision during the day.
Anatomy and Physiology of Lacrimal system SristiThakur
The document provides information on the anatomy and physiology of the lacrimal system and lacrimal drainage pathway. It describes the development, structure, blood supply, innervation and functions of the lacrimal glands, lacrimal puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It also discusses the physiology of tear drainage via the Rosengren-Doane pump mechanism and clinical tests like the Jones dye test, fluorescein dye disappearance test, and lacrimal syringing test that are used to evaluate the lacrimal drainage pathway.
The eyelids are composed of several layers of tissue and perform important protective and lubricating functions for the eyes. They contain glands that secrete oils to form the outer layer of the tear film and help spread tears across the cornea. The eyelids are innervated by cranial nerves and contain muscles that open and close the palpebral fissure, protecting the eyes from damage and keeping them moist.
This document discusses choroidal coloboma, beginning with definitions and epidemiology. It describes the embryonic development of the eye and how failure of fusion of the embryonic fissure can result in coloboma. Types of coloboma are classified based on location and presence of other anomalies. Complications like retinal detachment are discussed. Management of cataracts and other ocular issues in the context of coloboma are covered. The prognosis depends on factors like presence of microphthalmos, corneal diameter, and type and timing of surgery.
The eye receives its blood supply from two vascular systems - the retinal vessels and the ciliary (uveal) vessels. The retinal vessels include the central retinal artery and vein, which arise from the ophthalmic artery, a branch of the internal carotid artery. The ciliary vessels include the anterior and posterior ciliary arteries. Both systems anastomose to form circulations in the retina and choroid. The choroid has a dense capillary network called the choriocapillaris that supplies the outer retina. The retina and optic nerve have autoregulatory mechanisms to maintain constant blood flow despite changes in perfusion pressure, while the choroid has limited autoregulation.
Difference between follicles & papillae.Kape John
Follicles are localized areas of lymphoid hyperplasia that appear as white or gray elevations in the upper or lower tarsal conjunctiva and may be accompanied by inflammation. Papillae are flat-topped elevations in the tarsal conjunctiva containing blood vessels and having a smooth, velvety appearance, present in some forms of allergic conjunctivitis. The document distinguishes between follicles and papillae, defining each term and noting when they may be present.
• All structures are supplied by branches of
Internal Carotid Artery
• Except eyelids and conjunctiva which receives
blood supply from the branches of both
internal and external carotid artery
Central retinal artery
• First branch from the ophthalmic artery
• End arteries
• Divides into equal superior & inferior branches,
then another division (nasal & temporal)
Introduction Transparent,avascular,watch-glass like structure. Forms 1/6th part of outer fibrous coat (Sclera) It is the major refracting surface of the eye
3. Dimensions + Avg horizontal dia =11.75 mm (ant surface) + Avg vertical dia = 11 mm (ant surface ) + Avg dia (post surface)= 11.5 mm + Thickness(centre) =0.52mm + Thickness(peripheral) = 0.67mm + Radius of curvature (ant surface) = 7.8mm + Radius of curvature (post surface)= 6.5mm + Refractive power (ant surface) = +48D + Refractive power(post surface)= - 5D + R.I = 1.376
4. Histology + Epithelium + Bowman’s membrane + Stroma + Dua’s layer + Descemet’s membrane + Endothelium
5. Epithelium + Made up of stratified squamous epithelium + Thickness - 50-90 um + 5-6 layers of cells + Regenerative, entire epithelial layer is replaced every 6-8 days + Made up of 3 types of cells - basal,wing, flattened cells + Cells are attached by to each other by means of desmosomes & maculi occludents
6. Bowman’s membrane + Acellular,Non regenerative + Made up of condensed collagen fibrils. + Thickness - 12um + Resistant to infection & injury.
This document discusses the evaluation of the nasolacrimal system. It covers the history and anatomy of the system, classification of epiphora, diagnostic tests used to evaluate the system including anatomical tests like syringing and probing, functional tests like dye disappearance tests, and secretory tests like Schirmer's test. The document also discusses differentiating anatomical obstruction from functional/physiological causes of excessive tearing and localization of blockages in the system.
Vitreous hemorrhage occurs when blood leaks into the vitreous humor of the eye. It can be nondispersed, allowing some retinal view, or dispersed throughout the vitreous. Common causes include diabetic retinopathy, retinal vein occlusion, trauma, and posterior vitreous detachment. Patients experience painless vision loss and floaters. Examination may show a red eye or obscured retina. Treatment focuses on the underlying cause through laser, surgery, or observation depending on severity and risk factors.
The document discusses the extraocular muscles that control eye movement. It describes the six extraocular muscles - the four rectus muscles (medial, lateral, superior, inferior) and two oblique muscles (superior, inferior). It discusses their origins, innervation, blood supply, axes of rotation, actions, and roles as agonists, synergists and antagonists. It also covers concepts like position of rest, muscle planes, vergence movements, anomalies like tropias and phorias, and tests to evaluate eye movement.
anatomy and physiology of lacrimal apparatus pptRohit Rao
This document summarizes key aspects of the lacrimal system including its embryology, anatomy, physiology and role in tear formation and drainage. It discusses the lacrimal gland, canaliculi, lacrimal sac, nasolacrimal duct and meibomian glands. It also describes the layers of the tear film - glycocalyx, mucous, aqueous and lipid layers - and their functions in lubricating and protecting the eye. The document is a comprehensive overview of the lacrimal system and tear film.
This document defines and describes the anatomy and physiology of the lacrimal apparatus, which is responsible for tear formation and drainage in the eye. It discusses how lacrimal syringing is used to test the structural integrity of the lacrimal drainage system by passing fluid through the puncta and observing for any blockages or abnormalities. The document also outlines the equipment needed for lacrimal syringing and provides interpretations of different results that could indicate where in the drainage system a blockage may be located.
This document provides an overview of the anatomy and physiology of the lacrimal system. It describes the secretory apparatus including the lacrimal gland and accessory glands. It then describes the excretory apparatus including the puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It discusses the development of both the secretory and excretory systems. It provides details on the main lacrimal gland, lacrimal ducts, accessory lacrimal glands, lacrimal puncta, and canaliculi. It discusses the arterial supply, venous and lymphatic drainage, and nerve supply to the lacrimal gland. It covers the structure, functions, and applied
The lacrimal apparatus consists of the lacrimal gland, lacrimal drainage system, and associated structures that produce and drain tears from the eye.
The lacrimal gland develops from surface ectoderm and is located above and lateral to the eye. Tears produced by the gland drain through puncta and canaliculi into the lacrimal sac, then through the nasolacrimal duct into the nose.
The lacrimal sac is lodged in the lacrimal fossa of the medial orbital wall. It connects to the nasolacrimal duct, which courses posteriorly and laterally through bone to drain into the nasal cavity. Coordinated blinking and pressure differences aid
The retina is the light-sensitive tissue lining the back of the eye. It contains 10 layers including the retinal pigment epithelium, rods and cones, bipolar and ganglion cells. The retina is thinnest near the center and thickens toward the periphery. Key structures include the optic disc, macula with fovea for sharp central vision, and ora serrata marking the edge. The retina contains over 120 million light receptors and ganglion cells whose axons converge at the optic disc to form the optic nerve.
LIMBUS… • The limbus forms the border between the transparent cornea and opaque sclera, contains the pathways of aqueous humour outflow, and is the site of surgical incisions for cataract and glaucoma
2. Anatomical Limbus: Circumcorneal transitional zone of the conjunctivocorneal & corneoscleral junction Conjunctivo-corneal junction: • Bulbar conjunctiva is firmly adherent to underlying structures • Substantia propria of the conjunctiva stops here but its epithelium continues with that of the cornea. Sclero-corneal junction: • Transparent corneal lamellae become continuous • With the oblique, circular and opaque fibres of sclera
3. CONTINUE…. • In the area near limbus, the conjunctiva, tenon’s capsule & the episcleral tissue are fused into a dense tissue which is strongly adherent to corneo scleral junction.It is preferred site for obtaining a firm hold of the eyeball during ocular surgery. • The limbus is a common site for the occurrence of corneal epithelial neoplasm. • The Limbus contains radially oriented fibrovascular ridge known as the palisades of Vogt that may harbour a stem cell population. The palisades of Vogt are more common in the superior and inferior quadrants around the eye
The eyelids are thin folds of skin that protect the eye. They have three main functions - protection, regulation, and maintenance. The eyelids develop from embryonic processes and have several layers including skin, muscle, orbital fat, and conjunctiva. They are supplied by nerves from the oculomotor, trigeminal, and facial cranial nerves as well as the sympathetic nervous system. The eyelids help to spread tears and protect the eyes.
The optic nerve receives its blood supply from multiple sources along its path from the eye to the brain. In the eye, it is supplied by retinal arterioles and occasionally the ciliary artery. In the prelaminar region, it receives blood from ciliary region vessels and peripapillary choroidal or short posterior ciliary vessels. Deeper regions receive supply from ciliary and retinal circulations, including recurrent pial vessels and branches of the central artery of the retina. In the orbit, it has periaxial vessels from the ophthalmic artery and axial vessels from the central retinal artery. Within the cranium, it is supplied by the pial plexus fed by branches from the ophthalmic artery.
Binocular vision requires two clear eyes that can coordinate focusing on the same object. This allows the brain to fuse the two slightly different retinal images into a single image. There are grades of binocular vision including fusion and stereopsis, which is the ability to perceive depth. For binocular vision to develop, the eyes must maintain proper retinal correspondence and suppression. Tests like the Titmus fly test evaluate stereopsis. Understanding binocular vision and stereopsis is important for diagnosing and treating eye alignment disorders.
The document discusses the anatomy, embryology, and function tests of the macula lutea. It describes the macula lutea as a 5.5mm circular area at the posterior pole of the retina that subserves central vision. It notes the macula's delayed development until 8 months gestation and specialization of the fovea which contains the highest concentration of cones. The document outlines various macular function tests used to evaluate macular diseases, including visual acuity, Amsler grid, microperimetry, and electroretinography. It provides details on the anatomy and cell layers of the fovea centralis and techniques for assessing macular integrity with tests like the Maddox rod.
High myopia, or severe nearsightedness, is defined as a refractive error of -6.00 diopters or worse. It can be caused by genetic factors and environmental factors like extensive near work. Complications of high myopia include retinal detachment, glaucoma, cataracts, and pathological changes to the eye. Management options include spectacle correction, contact lenses, refractive surgery, and orthokeratology, which uses special contact lenses worn overnight to temporarily reshape the cornea and improve uncorrected vision during the day.
Anatomy and Physiology of Lacrimal system SristiThakur
The document provides information on the anatomy and physiology of the lacrimal system and lacrimal drainage pathway. It describes the development, structure, blood supply, innervation and functions of the lacrimal glands, lacrimal puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It also discusses the physiology of tear drainage via the Rosengren-Doane pump mechanism and clinical tests like the Jones dye test, fluorescein dye disappearance test, and lacrimal syringing test that are used to evaluate the lacrimal drainage pathway.
The eyelids are composed of several layers of tissue and perform important protective and lubricating functions for the eyes. They contain glands that secrete oils to form the outer layer of the tear film and help spread tears across the cornea. The eyelids are innervated by cranial nerves and contain muscles that open and close the palpebral fissure, protecting the eyes from damage and keeping them moist.
This document discusses choroidal coloboma, beginning with definitions and epidemiology. It describes the embryonic development of the eye and how failure of fusion of the embryonic fissure can result in coloboma. Types of coloboma are classified based on location and presence of other anomalies. Complications like retinal detachment are discussed. Management of cataracts and other ocular issues in the context of coloboma are covered. The prognosis depends on factors like presence of microphthalmos, corneal diameter, and type and timing of surgery.
The eye receives its blood supply from two vascular systems - the retinal vessels and the ciliary (uveal) vessels. The retinal vessels include the central retinal artery and vein, which arise from the ophthalmic artery, a branch of the internal carotid artery. The ciliary vessels include the anterior and posterior ciliary arteries. Both systems anastomose to form circulations in the retina and choroid. The choroid has a dense capillary network called the choriocapillaris that supplies the outer retina. The retina and optic nerve have autoregulatory mechanisms to maintain constant blood flow despite changes in perfusion pressure, while the choroid has limited autoregulation.
Difference between follicles & papillae.Kape John
Follicles are localized areas of lymphoid hyperplasia that appear as white or gray elevations in the upper or lower tarsal conjunctiva and may be accompanied by inflammation. Papillae are flat-topped elevations in the tarsal conjunctiva containing blood vessels and having a smooth, velvety appearance, present in some forms of allergic conjunctivitis. The document distinguishes between follicles and papillae, defining each term and noting when they may be present.
• All structures are supplied by branches of
Internal Carotid Artery
• Except eyelids and conjunctiva which receives
blood supply from the branches of both
internal and external carotid artery
Central retinal artery
• First branch from the ophthalmic artery
• End arteries
• Divides into equal superior & inferior branches,
then another division (nasal & temporal)
Introduction Transparent,avascular,watch-glass like structure. Forms 1/6th part of outer fibrous coat (Sclera) It is the major refracting surface of the eye
3. Dimensions + Avg horizontal dia =11.75 mm (ant surface) + Avg vertical dia = 11 mm (ant surface ) + Avg dia (post surface)= 11.5 mm + Thickness(centre) =0.52mm + Thickness(peripheral) = 0.67mm + Radius of curvature (ant surface) = 7.8mm + Radius of curvature (post surface)= 6.5mm + Refractive power (ant surface) = +48D + Refractive power(post surface)= - 5D + R.I = 1.376
4. Histology + Epithelium + Bowman’s membrane + Stroma + Dua’s layer + Descemet’s membrane + Endothelium
5. Epithelium + Made up of stratified squamous epithelium + Thickness - 50-90 um + 5-6 layers of cells + Regenerative, entire epithelial layer is replaced every 6-8 days + Made up of 3 types of cells - basal,wing, flattened cells + Cells are attached by to each other by means of desmosomes & maculi occludents
6. Bowman’s membrane + Acellular,Non regenerative + Made up of condensed collagen fibrils. + Thickness - 12um + Resistant to infection & injury.
This document discusses the evaluation of the nasolacrimal system. It covers the history and anatomy of the system, classification of epiphora, diagnostic tests used to evaluate the system including anatomical tests like syringing and probing, functional tests like dye disappearance tests, and secretory tests like Schirmer's test. The document also discusses differentiating anatomical obstruction from functional/physiological causes of excessive tearing and localization of blockages in the system.
Vitreous hemorrhage occurs when blood leaks into the vitreous humor of the eye. It can be nondispersed, allowing some retinal view, or dispersed throughout the vitreous. Common causes include diabetic retinopathy, retinal vein occlusion, trauma, and posterior vitreous detachment. Patients experience painless vision loss and floaters. Examination may show a red eye or obscured retina. Treatment focuses on the underlying cause through laser, surgery, or observation depending on severity and risk factors.
The document discusses the extraocular muscles that control eye movement. It describes the six extraocular muscles - the four rectus muscles (medial, lateral, superior, inferior) and two oblique muscles (superior, inferior). It discusses their origins, innervation, blood supply, axes of rotation, actions, and roles as agonists, synergists and antagonists. It also covers concepts like position of rest, muscle planes, vergence movements, anomalies like tropias and phorias, and tests to evaluate eye movement.
anatomy and physiology of lacrimal apparatus pptRohit Rao
This document summarizes key aspects of the lacrimal system including its embryology, anatomy, physiology and role in tear formation and drainage. It discusses the lacrimal gland, canaliculi, lacrimal sac, nasolacrimal duct and meibomian glands. It also describes the layers of the tear film - glycocalyx, mucous, aqueous and lipid layers - and their functions in lubricating and protecting the eye. The document is a comprehensive overview of the lacrimal system and tear film.
This document defines and describes the anatomy and physiology of the lacrimal apparatus, which is responsible for tear formation and drainage in the eye. It discusses how lacrimal syringing is used to test the structural integrity of the lacrimal drainage system by passing fluid through the puncta and observing for any blockages or abnormalities. The document also outlines the equipment needed for lacrimal syringing and provides interpretations of different results that could indicate where in the drainage system a blockage may be located.
The lacrimal apparatus produces and drains tears from the eye. The lacrimal gland secretes tears into the conjunctival sac. Tears drain from the inner canthus into the lacrimal sac through puncta and canaliculi, then into the nasolacrimal duct which empties into the nasal cavity. Tears lubricate the eye, contain antimicrobial agents, and drain into the nose.
The lacrimal apparatus is responsible for tear formation and drainage. It includes the lacrimal gland, conjunctival sac, lacrimal puncta, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct. The lacrimal gland secretes tears into the superior fornix to moisten the cornea and conjunctiva. Tears drain through the lacrimal puncta and canaliculi into the lacrimal sac and then through the nasolacrimal duct into the nasal cavity. The lacrimal gland, sac, canaliculi, and duct work together to produce tears and efficiently drain them from the eye.
This document discusses watering eye (epiphora) and its causes including hyperlacrimation and obstruction of tear outflow. It describes various mechanical obstructions that can cause epiphora such as punctal, canalicular, lacrimal sac or nasolacrimal duct obstructions. Clinical evaluation methods are outlined. Dacryocystitis, an infection of the lacrimal sac, is discussed including its congenital and acquired forms. Congenital dacryocystitis presents in newborns with epiphora, positive regurgitation test and swelling. Acquired dacryocystitis can be chronic or acute, with chronic forms including catarrhal dacryocystitis, lacrimal
Dry eye is a multifactorial disease that results in ocular discomfort and visual disturbance. It is caused by decreased tear production or increased tear evaporation, which leads to ocular surface inflammation and damage. Dry eye ranges in severity from mild intermittent symptoms to severe constant symptoms that limit daily activities. It is more common in older adults and women, and environmental factors, medications, contact lens use, and autoimmune diseases can trigger or exacerbate dry eye.
The document summarizes the anatomy and physiology of the lacrimal apparatus. It describes the main structures including the lacrimal gland, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It discusses the development, structure, blood supply, innervation and functions of each part. A number of clinical tests used to evaluate the lacrimal system for obstructions or other causes of epiphora are also outlined.
The document describes the anatomy and physiology of the lacrimal apparatus. It discusses the following key points:
- The lacrimal apparatus includes the lacrimal gland and associated drainage system for tear production and transport.
- The main structures are the lacrimal gland, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. Tears drain from the puncta through these structures and into the nose.
- The lacrimal gland secretes tears in response to sensory nerve stimulation. Contraction of surrounding muscles aids in drainage and prevents backflow through the puncta.
- Obstruction at any point can cause excess tearing (epiphora) by
The lacrimal apparatus consists of the lacrimal gland, lacrimal drainage system, and associated structures that produce and drain tears from the eye.
The lacrimal gland develops from surface ectoderm and consists of an orbital and palpebral part. Tears are secreted into the superior fornix via 10-12 lacrimal ducts. The tears then drain through the puncta, canaliculi, lacrimal sac, and nasolacrimal duct into the nasal cavity.
The lacrimal sac is located in the lacrimal fossa and connects to the nasolacrimal duct, which courses through the nasolacrimal canal before opening into the inferior
The document discusses various disorders of the lacrimal system including dry eye, epiphora, and lacrimal drainage system obstruction. It describes the signs and symptoms, causes, and treatment approaches for different conditions like keratoconjunctivitis sicca, mucin deficiency, oily layer abnormalities, and lacrimal gland inflammation and tumors. It also covers episcleritis, scleritis, and posterior scleritis providing classifications, associated systemic diseases, investigations and treatments.
The document discusses the anatomy and physiology of the lacrimal system and tear film. It describes the main structures of the lacrimal apparatus including the lacrimal gland, accessory lacrimal glands, lacrimal passages, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It discusses tear film layers, secretion, and functions. It also summarizes common lacrimal system disorders like dry eye, dacryocystitis, epiphora, dacryoadenitis and their signs, symptoms, etiologies, and treatments. Surgical procedures for these conditions like dacryocystorhinostomy are also briefly outlined.
Dry eye is a disease of the ocular surface caused by disturbances in the tear film. The normal tear film consists of an inner mucin layer, middle aqueous layer, and outer lipid layer, which work together to form a stable tear film. Disruptions to the tear film components or their functions can lead to dry eye. Common tests to diagnose dry eye include tear break-up time, fluorescein clearance, and tear osmolarity measurement, which help identify tear film instability and inflammation associated with the condition.
Dry eye occurs when there is inadequate tear production or function, resulting in an unstable tear film and ocular surface disorder. It can be caused by conditions that reduce tear production such as Sjogren's syndrome, vitamin A deficiency, Stevens-Johnson syndrome, or medications. Other causes affect the tear film layers, like meibomian gland dysfunction reducing the outer lipid layer. Symptoms include dryness, burning, and blurred vision. Treatment focuses on replacing tears, improving ocular surface health, addressing underlying causes, and escalating care based on severity through the DEWS treatment guidelines.
Diagnosis, Management, and Surgery by Adam J. Cohen, Michael Mercandetti & Brian G. Brazzo. The dry eye , a practical approach by Sudi Patel & Kenny J Blades. Jack J Kanski’s clinical ophthalmology Clinical Anatomy of the Eye by Richard S. Snell & Michael A. Lemp.
3. It is concerned with the tear formation & transport. Lacrimal passage includes : Lacrimal gland Conjunctival sac Lacrimal puncta Lacrimal canaliculi Lacrimal sac Nasolacrimal duct
4. The following components of the lacrimal apparatus are discussed : Embryology Osteology Secretory system Excretory system Physiology
5. Ectodermal origin Solid epithelial buds(first 2 months) Supero
This document provides an overview of the anatomy and embryology of the lacrimal apparatus. It describes the secretory and drainage portions, including the main and accessory lacrimal glands, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. Details are given on histology, blood supply, innervation and functions. The structure and layers of the tear film are explained. The dynamic process of tear secretion, formation, distribution, evaporation and drainage is summarized.
This document summarizes the anatomy and physiology of the lacrimal apparatus. It describes the main structures involved, including the lacrimal gland, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It discusses the blood supply, nerve supply, and secretory function of the lacrimal gland. Causes of watering eyes such as hyperlacrimation and epiphora are also outlined.
The lacrimal apparatus is the physiological system containing the orbital structures for tear production and drainage. It consists of: The lacrimal gland, which secretes the tears, and its excretory ducts, which convey the fluid to the surface of the human eye;it is a serous gland located in lacrimal fossa.
The lacrimal system consists of the lacrimal glands and lacrimal passages. The lacrimal passages include the puncta, canaliculi, lacrimal sac, and nasolacrimal duct. Tears are produced by the main and accessory lacrimal glands and drain through the puncta and canaliculi into the lacrimal sac and then the nasolacrimal duct into the nose. The tear film covering the cornea consists of three layers - a mucus layer, aqueous layer, and lipid layer - and serves to moisten and protect the eye.
The lacrimal apparatus consists of the lacrimal gland, accessory lacrimal glands, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. The lacrimal gland develops from ectodermal buds and secretes tears. Tears drain through the puncta and canaliculi into the lacrimal sac, then through the nasolacrimal duct into the nose. Contraction of the orbicularis oculi muscle aids in tear drainage by creating pressure changes in the lacrimal sac.
The document describes the anatomy and physiology of the lacrimal apparatus. It discusses the following key points:
- The lacrimal apparatus includes the lacrimal gland and associated structures that produce and drain tears such as the puncta, canaliculi, lacrimal sac, and nasolacrimal duct.
- The lacrimal gland is divided into orbital and palpebral parts. Tears are produced by serous acinar cells and drained through a series of ducts.
- Tears drain from the eye through the puncta and canaliculi into the lacrimal sac, then through the nasolacrimal duct and into the nose. Drainage is aided by
The eyelids are composed of several layers including skin, superficial fascia, palpebral fascia, and conjunctiva. The palpebral fascia forms the tarsal plates which provide stiffness to the lids. The tarsal plates contain meibomian glands whose ducts open at the lid margins. The lacrimal apparatus includes the lacrimal gland, conjunctival sac, lacrimal puncta and canaliculi, lacrimal sac, and nasolacrimal duct which secretes and drains tear fluid from the eye. The face develops from five processes- frontonasal, two maxillary, and two mandibular processes. Canalization of an ectodermal
The lacrimal system includes structures involved in tear production and drainage. Tears are produced by the lacrimal gland and drained through the puncta, canaliculi, lacrimal sac, and nasolacrimal duct. Obstructions anywhere in the lacrimal passage can cause epiphora or swelling. Congenital anomalies such as atresia or ectasia of the lacrimal passage can also cause drainage issues. The lacrimal system has important functions in maintaining the tear film and eye health.
This document summarizes the anatomy and examination of the lacrimal apparatus system. It describes the main structures including the lacrimal gland, puncta, canaliculi, lacrimal sac, and nasolacrimal duct. It then discusses the clinical evaluation of a "watering eye" case through slit lamp examination, the regurgitation on pressure over lacrimal apparatus system test, fluorescein dye disappearance test, diagnostic probing, and syringing. The document aims to provide an overview of the lacrimal drainage system and methods for examining obstructions.
The lacrimal apparatus is responsible for tear formation and drainage. It includes the lacrimal gland, conjunctival sac, lacrimal puncta, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct. The lacrimal gland secretes tears into the conjunctival sac. Tears are drained from the puncta through the canaliculi and lacrimal sac into the nasolacrimal duct. Blinking aids in drainage by compressing the canaliculi and lacrimal sac to push tears into the nasolacrimal duct.
The conjunctiva is the mucous membrane that lines the inner surface of the eyelids and covers the anterior surface of the sclera and cornea. It has three layers - an epithelial layer, adenoid layer, and fibrous layer. The conjunctiva receives its blood supply from the marginal arterial arcade, peripheral arterial arcade, and anterior ciliary arteries. It drains into the venous plexus of the eyelids and then into the superior and inferior ophthalmic veins. Lymphatic drainage is to the preauricular and submandibular lymph nodes. Pterygium is a wing-shaped growth of conjunctiva that extends onto the cornea, caused by exposure to sun and dust, and is
This document describes the anatomy and structure of the lacrimal apparatus, which produces and drains tears from the eyes. It includes the main lacrimal gland located in the orbit, accessory lacrimal glands in the eyelid, and the lacrimal drainage system consisting of puncta, canaliculi, lacrimal sac, and nasolacrimal duct leading to the nose. The main lacrimal gland is a serous gland made of acini and ducts and receives blood supply from the lacrimal artery and drains to the ophthalmic vein. Tears produced drain through puncta and canaliculi into the lacrimal sac then through the nasolacrimal duct to
The conjunctiva is a thin mucous membrane that lines the eyelids and covers the sclera of the eye. It has several parts: the palpebral conjunctiva lines the inner eyelid, the bulbar conjunctiva covers the sclera, and the fornix joins the two. It contains goblet cells that secrete mucus to lubricate the eye and glands that further supplement tear production. Blood vessels in the conjunctiva deliver nutrients and immune cells to protect the eye surface. Nerves innervate the conjunctiva for sensation from the trigeminal nerve and cervical sympathetic nerves regulate blood vessels.
The document describes the anatomy and common diseases of the eyelids. It discusses the layers of the eyelid including skin, muscles, glands and conjunctiva. It describes common inflammatory conditions like blepharitis which can affect the eyelid margins and meibomian glands. The document also discusses structural abnormalities of the eyelids including entropion, ectropion, ptosis and distichiasis. Surgical treatments are mentioned for some conditions.
The conjunctiva is a thin mucous membrane that covers the posterior eyelid and anterior sclera. It is responsible for mucus production and has an inflammatory response to protect the eye. The conjunctiva has different regions - palpebral, bulbar, forniceal - that contain glands, goblet cells, blood vessels and nerves. Goblet cells secrete mucus to form the outer layer of the tear film and protect the ocular surface. The conjunctiva helps maintain a healthy ocular surface and provides the first line of defense against pathogens.
The lacrimal apparatus (Tear System)
It's a group of glands, sacs and ducts that makes new tears and drains old ones away. consists of two divisions. The first is the secretory part, which is responsible for the production of tears, and the second is the drainage part. The secretory part contains the main lacrimal gland, which is lodged in a fossa in the lateral part of the roof of the orbit, and two accessory lacrimal glands of Krause and Wolfring. The latter are present near the fornix.
The document provides an overview of the surgical anatomy of the eyelid. It discusses the key structures of the eyelid in 3 layers - skin, muscle, and fibrous layer. The skin is the thinnest in the body to allow for easy eyelid mobility. The muscle layer contains the orbicularis oculi muscle which helps protract the eyelid. The fibrous layer provides the framework and includes the tarsal plates, septum orbitale, and medial/lateral palpebral ligaments. It also describes important anatomical structures like the palpebral fissure, canthi, eyelid margins and creases. Blood supply comes from the medial and lateral palpebral arteries which form marginal arterial arc
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Journal club about computer vision syndrome suraj chhetriSuraj Chhetri
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3. INTRODUCTION
Lacrimas in latin : a tear
Lacrimal gland is
exocrine gland
Secretes aqueous
component of tear
It is located under the
superotemporal
orbital rim in a shallow
fossa of the frontal bone.
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4. EMBROYOLOGY
Lacrimal gland
Starts to develop from multiple solid ectodermal buds
arising from the basal cells of conjunctiva in the
superotemporal region of fornix at 6th-7th weeks
Mesenchyme surrounds these buds and proliferates to form
the parenchyma of the lacrimal gland
Buds branch and canalize to form ducts and alveoli
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5. At 5th month of gestation lateral horn of levator
aponeurosis divides it into palpebral and orbital part
Lacrimal glands do not function fully until
approximately 6th week of life
Accessory lacrimal glands are formed from
ectodermal invagination of conjunctiva which
detected at 6 to 7 months
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7. Nasolacrimal duct
Maxillary process grows medially to override paraxial
mesoderm of the nasolacrimal process
Nasooptic fissure is thus formed
Surface ectoderm within the fissure thickens in a
cord-like fashion
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8. cords of epithelium invaginate at the upper and lower
lid margins, eventually forming the canaliculi. These
epithelial cords fuse to form the nasolacrimal
drainage system.
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12. Main lacrimal gland (Tear gland)
SITE- in lacrimal fossa formed by
orbital plate of frontal bone in the
anterolateral roof of orbit
SHAPE-almond shaped
TYPE-exocrine
PART-superior orbital and inferior
palpebral part
Separated by lateral horn of
aponeurosis of levator muscle.
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13. Structure of lacrimal gland
Branched tubulo-alveolar gland
Similar to salivary gland
Microscopically, it has glandular
tissue, stroma & septa.
1)Glandular tissue: consists of acini
and ducts arranged in lobes and
lobules. This lobules joins to form
intralobular ducts which finally
joins to form extralobular ducts.
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14. 2)Stroma: connective
tissue, elastic tissue,
lymphoid tissue,
plasma cell, nerve
terminals and blood
vessels
3)Septa: fibrovascular in
nature and separates
lobes and lobules from
each other
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15. Acinar unit (secretory unit)
Columnar or pyramidal
shaped secretory cells
(luminal surface of the
secretory cell has
microvilli)
Central lumen
Surrounding basal layer
of myoepithelial cells (aid
in expulsion of secretion )
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16. Clinical significance
1. Acute dacryoadenitis
Inflammation of lacrimal gland.
Develop as primary inflammation of the
gland or secondary to some local
infection as in trauma,
conjuctivitis(especially gonococcal and
staphylococcal) and orbital cellulitis or
systemic infection like mumps,
infleunza, measles.
Clinical feature: inflammation of
palpebral part, painful swelling in
lateral part of upper lid, typical S-
shaped curve of lid.
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17. 2. Chronic dacryoadenitis (mikulicz’s syndrome)
A chronic enlargement of lacrimal gland secondary to
systemic disease and associated with salivary gland
enlargment
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19. Accessory Lacrimal gland
Glands of Krause:
In the subconj. tissue near fornices.
About 40-42 in upper lid,
6-8 in lower lids.
More numerous laterally.
Supply aqueous phase of
basal tear film.
Glands of wolfring:
Situated near upper border of
superior tarsus plate, 2-5 in upper lid.
lower border of inferior tarsus, 2-3 in lower lid
Supply aqueous phase of the basal tear film.
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20. LACRIMAL DUCTS
10-12 lacrimal ducts
2-5from orbital portion
6-8 from palpebral portion
The ducts from the orbital portion joins with the
palpebral portion & finally open into the superior fornix
approx.5mm above the lateral tarsus border
Clinical importance: Removal or damage even only
to the palpebral portion of the gland amounts to the
excision of the entire gland as far as secretory function is
concerned
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21. Clinical importance
Lacrimal ductal cyst(dacryops)
Cystic swelling , which occur due to retention of
lacrimal secretion following blockage of the lacrimal
ducts
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22. Blood supply:
Supplied by lacrimal artery - ophthalmic artery –
internal carotid artery.
Sometimes transverse facial artery & infraorbital artery
supplies
The lacrimal vein joins to the superior ophthalmic vein
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26. Lacrimal punctum
Small rounded or oval opening.
In upper and lower eyelid at
junction of ciliary and lacrimal
portion of lid margin
Upper-6mm and lower 6.5mm
later to inner canthus
On closure of eyelid punctum
do not overlap
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27. Contd…
Each punctum sits on
top of an elevated
mound known as the
papilla lacrimalis.
They are relatively
avascular in comparison
to the surrounding
tissue, giving them a pale
appearance, which is
accentuated with lateral
traction of the lid.
This pallor can be
helpful in localizing a
stenosed punctum.
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28. Lacrimal canaliculi
LENGTH-Each are 8-12mm long
LENGTHCOURSE-2mm vertical&8-10mm
horizontal.
UNION-90% they unite as a common
canaliculus and in about
10% opens separately in lateral
wall of the orbital sac.
VALVE-Valve of Rosenmuller,a mucosal
fold overhangs the junction
between common canaliculi
and prevents reflux.
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29. ANGLE- between the vertical and horizontal segments
is approximately 90 degrees, and the canaliculi dilate
at the junction to form the ampulla..
LININGS-by nonkeratinized stratified
squamous epithelium and are surrounded by
elastic tissue, which permits dilation to 2 or 3
times the normal diameter.
CLINICAL SIGNIFICANCE
An incompetent valve of rosenmullar is observe
clinically as air escaping From the lacrimal
puncta when the indivisual blows his or her
nose
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30. Canaliculitis
Inflammation of canalaiculi.
Casuative agent: actinomyces israelii.
Presentation: unilateral epiphora with chronic
mocopurulent conjuctivitis.
Signs: pouting punctum, pericanalicular
inflammation, mucopurulent discharge on pressure
over the canaliculus. Concretions consisting of sulphur
granules can be expressed.
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31. Oedema and pouting of
punctum
Expressed concretions with
sulphur granules
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32. LACRIMAL SAC
Site lacrimal fossa: (anterior part of medial orbital
part) where sac is encovered by lacrimal fasica
(periorbita i.e periosteum lining of orbit)
Length: 15mm
Volume : 20cc
Parts :fundus (3-5mm) , body (10-12mm) & neck
Lining of double layer epithelium (upper is columnar
and deeper is falter)
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33. Relations
Medial to sac separated by periorbita and bone lie –
anterior ethmoidal sinuses
Below it lies: nasal middle meatus
Lateral to it lies skin ,part of orbicularis oculi,
lacrimal fascia
Anteriorly lies the medial palpebral ligament &
angular vein
Posterior to sac lies lacrimal fasica & septum orbitale
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39. Contd…
Lower end- opens into the nose through an ostium
under the inferior turbinate, covered by valve of
Hasner.
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40. Blood supply and nerve supply to
lacrimal passage
Superior and inferior palpebral arteries (ophthalmic
artery) and also by infraorbital artery , angular artery
&branch of sphenopalatine artery
Infratrochlear nerve – ophthalmic division of
trigeminal nerve and also by anterior superior alvolar
nerve
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41. CLINICAL IMPORTANCE
CNLDO (Congenital nasolacrimal duct
obstruction)-failure of the canalization of the NLD after
birth
In fetus, the NLD is a solid cord of cells, which gets
canalized at birth. In 30% of new borns canalization is
delayed. This congenital NLD blockage causes epiphora
predisposing to congenital dacryocystitis.
PANDO (primary acquired nasolacrimal duct
obstruction)-an entity of nasolacrimal duct obstruction
caused by inflammation or fibrosis without any
precipitating cause.. studies have revealed inflammation,
vascular congestion, and edema of the nasolacrimal duct in
the early phases and, ultimately, fibrosis with complete
occlusion of the nasolacrimal duct's lumen in the late
phases.
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42. SALDO(secondary acquired lacrimal
drainage obstruction)
has some etiology : infectious Bacteria such as
• Actinomyces
• Fusobacterium
• Bacteroides
• Mycobacterium
• Chlamydia
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43. Congenital nasolacrimal duct obstruction
Epiphora and matting
Infrequently acute dacryocystitis
Massage of nasolacrimal duct
and antibiotic drops 4 times
daily
Improvement by age 12
months in 95% of cases
If no improvement - probe at
12-18 months
Results - 90% cure by first
probing and 6% by second
Treatment
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44. Remnants of epithelium within the cords form inconsistent
valve like folds which are diagrammatically represented
.
1, valve of RosenMuller
2, valve of Krause
3, spiral valve of Hyrtl
4, valve of Taillefer
5, valve of Hasner or
plica lacrimalis.
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46. Secretion of tears
Continously secreted through out the day by main
&accessory lacrimal gland
Rate of tear production -1.2microl/min
tear vol.-7 micro lit
2 Components:
Basic Secretors
Reflex Secretors
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47. Basic Secretors
mucin secreting goblet cell
of conjunctiva
Accessory lacrimal gland of
krause & Wolfring
tarsal gland
Gland of Zeiss & Moll
47/77
48. Reflex secretion
due to irritation of 5th cranial nerve in response to
sensation from cornea and conjunctiva.(mainly by lacrimal
gland)
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50. Lacrimal pump mechanism
The secreted tear flows over the ocular surface and
reaches marginal tear strip running along the ciliary
margin of each eyelids and collects as lacrimal lacus in
inner canthus.
From there it is drained to nasal cavity via lacrimal
excretory system by active lacrimal pump mechanism.
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51. Working of lacrimal pump
mechanism
Operates with the
blinking movements.
Performed by orbicularis
muscle of eyelid.
Two major events
• Eyelid closure
• eyelid open
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52. On eyelid closure following events occur
concomitantly
Contraction of pretarsal fibres of orbicularis compress the
ampulla and shortens the canaliculi.
This movement propels the tear fluid present in the
ampulla and horizontal part of canaliculi toward the
lacrimal sac
Contraction of preseptal fibres pulls the lacrimal fascia
and lateral wall of the sac laterally thus opening the
normally closed lacrimal sac.
This produces negative pressure and draws the tear from
canaliculi to lacrimal sac.
At the same time inferior portion closes more tightly thus
preventing aspiration of air from nose.
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53. On eyelid opening following events occur
concomitantly
Relaxation of pretarsal fibres allows canaliculi to
expand and reopen. This draws the tearfluid through
the punctum from the lacrimal lake.
Relaxation of preseptal fibres allows the lacrimal sac to
collapse which inturn expels the fluid downard into
open NLD.
At the same time puncta moves laterally, canaliculi
lengthens and is filled with tears.
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55. Drainage into the nasal cavity
Gravity
Air current movement within the nose
Final entry of tears into the nose :facilitated by
opening of Valve of Hasner which widens
synchronously with opening of lids
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56. Tear film
It consist of three layars
1. Mucous layer: subconjunctival
goblet cells
2. Aqueous layer: main and
accessory lacrimal glands
3. Lipid layer :Meibomian gland
Gland of Zeis and Moll
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57. Lipid layer
Outermost layer
Secreted by meibomian gland, zeiss and moll gland
Thickness-0.1micrometre
Consist of polar and nonpolar lipid
This layer prevents the overflow of tear and also
evaporation of tear
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58. Aqueous layer
Middle layer.
Secreted by lacrimal gland and accessory gland of
krause.
Thickness: 6.5-7.5 micrometre.
Constitute main bulk of tear.
Consist of inorganic salts, glucose, urea, and various
biopolymers like proteins(Ig A), antibacterial agent(
lysozyme, lactoferrin).
This layer serves to provide atmospheric oxygen to
epithelium,washes away debris and noxious agent,
maintain the normal level of electrolyte over occular
surface epithelium.
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59. Mucin layer
Innermost layer
Secreted by conjuctival goblet cells
This layer makes the hydrophobic corneal surface
hydrophilic overwhich the aqueous and lipid layer get
adheres. Thus plays a vital role in stability of tear film
Act as lubricant during eye movement
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60. Tear film abnormalities
Dry Eye
It is the state of abnormal tear film that can be caused
by number conditions which alter its composition and
affect stability.
Normal tear Tear in dry eye
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61. Tear film abnormalities classification on
the basis of physiological consideration:
(holly and lemp )
Aqueous deficiency
Mucin deficiency
Lipid abnormality
Impaired lid function
epitheliopathy
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62. Tests for tear film adequacy
Schirmer test:
assess aqueous tear
production.
Performed with whatmann 41
filter paper.
Two type:
Schirmer I: without anesthesia
Normal lower limit is 10mm
of wetting after 5min
Schirmer II: use of anesthesia
Normal lower limit is 6mm
after 5min
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63. Tear film break-up time
Indicate adequacy of mucin
component of tear
It is the time interval between
complete blink and
appearance of first randomly
distributed dry spot on
cornea.
Done by instillation of
fluorescein drop 2% or
impregnated fluoresceinstrip.
Examined under cobalt blue
light of slit lamp.
TBUT value less than 10 sec is
said to be dry eye.
63/77
64. Clinical correlation of lacrimal
apparatus
Watering eye
Implies overflow of the tears from conjuctival sac
Occur due to :
• Excessive secretion of tears(hyperlacrimation)
• Obstruction of lacrimal passage
64/77
65. Clinical evaluation of watering eye
1. External Ocular examination with slit lamp:
Ectropion
entropion
Punctal obstruction by an eyelash
Large carauncle displacing punctum away from
globe
Pouting punctum
Any occular FB
65/77
66. 2.Regurgitation test
A steady pressure with index finger over lacrimal sac
area is applied.
Punctal reflux of mucopurulent material on
compression indicates patent canalicular system with
obstruction at lacrimal sac or NLD
66/77
67. 3. Fluorescein dye disappearance
test(FDDT)
Performed with instillation of 2% fluorescein dye in
both conjuctival fornices.
Observations made after 2 min.
No dye is seen in conjuctival sac-patent passage
Retention of dye –inadequate drainage due to atonia of
sac or mechanical obstruction.
67/77
68. 4. Lacrimal syringing test
Local anesthetic(4% xylocaine) is instilled
Punctum is dilated if narrow
Gently curved, blunt tipped lacrimal cannula on a
2mm saline filled syringe is inserted into lower puncta
and advanced few mm following the contour of the
cannulus prior to irrigation
68/77
69. Then after, normal saline is pushed into
lacrimal sac . The following conditions are
obtained:
1. Free passage of saline indicate patency of lacrimal
passage.
2. Clear fluid from same puncta indicate same pucta
block.
3. Clear fluid from opposite puncta indicate
common camnalicular block.
4. Mucoid fluid from opposite puncta indicate NLD
block.
69/77
70. Probe test
The hard stop and soft stop is encountered
Hard stop indicates the patency of lacrimal canaliculi
Occurs when cannula enters the lacrimal sac but comes
to stop at the medial wall of sac
Soft stop indicates the non-patency of canaliculi
Occurs when cannula donot enter lacrimal sac and
presses the soft tissue of common canaliculus
70/77
72. 5. Jones dye testing
Performed in patients with suspected partial obstruction of the
drainage system.
Type:
John testI: differentiate between watering due to partial
obstruction and hypersecretion of tear.
John test II: identifies probable site of partial obstruction. Done
after John I.
Two drops of 2% fluorescein dye is instilled in conjuctival sac and a
cotton bud dipped in 1% xylocaine is placed in inferior meatus after 5
min.
John test I:
Positive: fluorescien is recovered from the nose indicating
patency of drainage system. Watering is due to primary
hypersecretion.
Negative: no dye is recovered indicating a partial obstruction. In
this case John II is recommended.
72/77
73. John test II:
Cotton bud is placed in inferior meatus and syringing
is performed after application of anesthetic.
Positive: fluorescein stained saline is recovered from
nose. Here fluorescein has entered in sac thus
conforming patency of upper lacrimal passage.
Negative: unstained saline is recovered from the
nose. It indicates no entry of dye in lacrimal sac and
implies partial obstruction of puncta, canaliculi or
common canaliculus.
73/77
74. Introduction to obstruction of lacrimal passage
Punctal obstruction:
Primary punctal stenosis:
caused in absence of punctal
eversion e.g due to chronic
blepharitis, herpes simplex,
herpes zooster, cicatrizing
conjuctivitis, trachoma etc
Secondary punctal
obstruction: caused by
punctal eversion.
74/77
75. Canalicular obstruction:
Occurs due to congenital
trauma, herpes simplex
infection, drugs and chronic
dacryocystitis.
Nasolacrimal duct
obstruction:
Congenital,idioapthic, naso-
orbital trauma,granulomatous
disease like
sarcoidosis,infiltration by
nasophyrangeal tumors.
Dacryoliathiasis: lacrimal stone
in any part of lacrimal system.
75/77