This study used MRI to assess optic nerve degeneration in a monkey model of experimental glaucoma induced by laser photocoagulation. MRI was performed on 8 monkeys approximately 2 years after laser treatment to one eye. Diffusion tensor imaging parameters including axial and radial diffusivity, fractional anisotropy, and apparent diffusion coefficient were analyzed in the optic nerves and correlated with intraocular pressure measurements. Results showed that as intraocular pressure increased, optic nerve cross-sectional area decreased and diffusivity parameters increased linearly while fractional anisotropy decreased linearly, indicating optic nerve degeneration correlated with elevated intraocular pressure. This study demonstrates MRI can quantify in vivo optic nerve degeneration related to glaucoma and may be useful for evaluating potential therapies.
This document discusses Ocularis Pharma's Nyxol eye drops, which are intended to treat higher-order aberrations by reducing pupil size in dim light. It provides background on higher-order aberrations, their causes and prevalence. It explains that Nyxol contains phentolamine, phenoxybenzamine and tetrahydrozoline to selectively block alpha-1 receptors and inhibit pupil dilation while countering redness. Clinical trials showed Nyxol improved low-light vision and was well-tolerated. The document seeks discussion on Nyxol's pharmacological combination, clinical trial results, most prevalent higher-order aberration, and licensing arrangements.
This study assessed the feasibility of using a portable optical coherence tomography (OCT) device to measure retinal parameters in multiple sclerosis (MS) patients both with and without a history of optic neuritis (ON). OCT scans of 137 eyes from 71 MS patients found thinning of the retinal nerve fiber layer, ganglion cell complex, and macular thickness in eyes with a history of ON compared to those without. Contrast sensitivity scores using the Pelli-Robson test also correlated with retinal thinning. The semi-automated OCT device provided detailed retinal measurements within clinical care and could stratify patients based on prior ON history.
The synoptophore is an instrument used in orthoptics to test binocular vision. It presents different images to each eye to test fusional abilities. The synoptophore was developed in the early 20th century based on the haploscopic principle. It uses mirrors and lenses to direct different images to each eye. Various models have different additional features like afterimage devices, automatic flashing, and measurement of vertical/torsional deviations. A wide range of slides can test functions like stereopsis, fusion, suppression, and retinal correspondence. The synoptophore is useful for both diagnosing binocular vision disorders and providing vergence therapy.
This document summarizes research on the effectiveness of vision therapy in improving visual function. It discusses what vision therapy is and how it can be used to treat various visual disorders like binocular vision problems, eye movement issues, focusing difficulties, strabismus, amblyopia, and nystagmus. The document reviews numerous studies demonstrating that vision therapy can successfully modify and improve visual skills like eye coordination, eye movements, and focusing abilities. It concludes that vision therapy is an effective clinical approach supported by a significant amount of research.
The synaptophore is a device used to measure binocular vision anomalies. It consists of two optical tubes that can be adjusted horizontally, vertically, and torsionally. Various slides are used for diagnostic and treatment purposes to measure deviations, fusion, stereopsis, and retinal correspondence. Key measurements include the objective and subjective angles of deviation in different gazes, as well as the fusional ranges in horizontal, vertical, and torsional planes. Suppression can also be detected and mapped out. Precise adjustments of the tubes allow customized orthoptic treatment of binocular vision disorders.
Binocular anomalies refer to disorders of binocular vision that include strabismus, amblyopia, and anomalies of vergence and accommodation. Some common binocular anomalies are esotropia, exotropia, vertical deviations, convergence insufficiency, and accommodative disorders. Causes can include refractive errors, ocular misalignment, neurological issues, or trauma. Symptoms may include diplopia, headaches, asthenopia, or blurred vision. Diagnosis involves assessing ocular alignment, binocular vision functions like stereopsis and suppression, and accommodative and vergence abilities. Treatment depends on the specific anomaly but may involve optical correction, vision therapy, or surgery.
This document discusses measuring and classifying accommodative convergence/accommodation (AC/A) ratios. It defines the AC/A ratio as the change in accommodative convergence per diopter of accommodation. Abnormal AC/A ratios can cause strabismus. There are several methods described for measuring the AC/A ratio clinically, including the heterophoria, gradient, and graphical methods. The document outlines treatments for different AC/A ratio abnormalities like convergence excess, convergence insufficiency, divergence excess, and divergence insufficiency.
Introduction to accommodative and binocular anomaliesHammed Sherifdeen
This document discusses accommodation and binocular anomalies. It defines accommodation as the eye's ability to change optical power to focus on objects at different distances. The components involved are the ciliary muscle, crystalline lens, zonules, and vitreous. Accommodation is stimulated by increasing object vergence through proximity or minus lenses. The amplitude of accommodation is the eye's total focusing range, measured using the RAF rule by finding the near point where a target first blurs and becomes clear again. It declines with age from about 14D at age 10 to 0.5D at age 60.
This document discusses Ocularis Pharma's Nyxol eye drops, which are intended to treat higher-order aberrations by reducing pupil size in dim light. It provides background on higher-order aberrations, their causes and prevalence. It explains that Nyxol contains phentolamine, phenoxybenzamine and tetrahydrozoline to selectively block alpha-1 receptors and inhibit pupil dilation while countering redness. Clinical trials showed Nyxol improved low-light vision and was well-tolerated. The document seeks discussion on Nyxol's pharmacological combination, clinical trial results, most prevalent higher-order aberration, and licensing arrangements.
This study assessed the feasibility of using a portable optical coherence tomography (OCT) device to measure retinal parameters in multiple sclerosis (MS) patients both with and without a history of optic neuritis (ON). OCT scans of 137 eyes from 71 MS patients found thinning of the retinal nerve fiber layer, ganglion cell complex, and macular thickness in eyes with a history of ON compared to those without. Contrast sensitivity scores using the Pelli-Robson test also correlated with retinal thinning. The semi-automated OCT device provided detailed retinal measurements within clinical care and could stratify patients based on prior ON history.
The synoptophore is an instrument used in orthoptics to test binocular vision. It presents different images to each eye to test fusional abilities. The synoptophore was developed in the early 20th century based on the haploscopic principle. It uses mirrors and lenses to direct different images to each eye. Various models have different additional features like afterimage devices, automatic flashing, and measurement of vertical/torsional deviations. A wide range of slides can test functions like stereopsis, fusion, suppression, and retinal correspondence. The synoptophore is useful for both diagnosing binocular vision disorders and providing vergence therapy.
This document summarizes research on the effectiveness of vision therapy in improving visual function. It discusses what vision therapy is and how it can be used to treat various visual disorders like binocular vision problems, eye movement issues, focusing difficulties, strabismus, amblyopia, and nystagmus. The document reviews numerous studies demonstrating that vision therapy can successfully modify and improve visual skills like eye coordination, eye movements, and focusing abilities. It concludes that vision therapy is an effective clinical approach supported by a significant amount of research.
The synaptophore is a device used to measure binocular vision anomalies. It consists of two optical tubes that can be adjusted horizontally, vertically, and torsionally. Various slides are used for diagnostic and treatment purposes to measure deviations, fusion, stereopsis, and retinal correspondence. Key measurements include the objective and subjective angles of deviation in different gazes, as well as the fusional ranges in horizontal, vertical, and torsional planes. Suppression can also be detected and mapped out. Precise adjustments of the tubes allow customized orthoptic treatment of binocular vision disorders.
Binocular anomalies refer to disorders of binocular vision that include strabismus, amblyopia, and anomalies of vergence and accommodation. Some common binocular anomalies are esotropia, exotropia, vertical deviations, convergence insufficiency, and accommodative disorders. Causes can include refractive errors, ocular misalignment, neurological issues, or trauma. Symptoms may include diplopia, headaches, asthenopia, or blurred vision. Diagnosis involves assessing ocular alignment, binocular vision functions like stereopsis and suppression, and accommodative and vergence abilities. Treatment depends on the specific anomaly but may involve optical correction, vision therapy, or surgery.
This document discusses measuring and classifying accommodative convergence/accommodation (AC/A) ratios. It defines the AC/A ratio as the change in accommodative convergence per diopter of accommodation. Abnormal AC/A ratios can cause strabismus. There are several methods described for measuring the AC/A ratio clinically, including the heterophoria, gradient, and graphical methods. The document outlines treatments for different AC/A ratio abnormalities like convergence excess, convergence insufficiency, divergence excess, and divergence insufficiency.
Introduction to accommodative and binocular anomaliesHammed Sherifdeen
This document discusses accommodation and binocular anomalies. It defines accommodation as the eye's ability to change optical power to focus on objects at different distances. The components involved are the ciliary muscle, crystalline lens, zonules, and vitreous. Accommodation is stimulated by increasing object vergence through proximity or minus lenses. The amplitude of accommodation is the eye's total focusing range, measured using the RAF rule by finding the near point where a target first blurs and becomes clear again. It declines with age from about 14D at age 10 to 0.5D at age 60.
The optom faslu muhammed is a haploscopic device used to assess binocular vision. It consists of two tubes mounted on a base with a chin rest and forehead rest. Each tube contains a light source, slide carrier, reflecting mirror, and +6.50D eye piece. It is used to test various grades of binocular vision like simultaneous macular perception, fusion, and stereopsis using different slides. It can also be used to measure the inter-pupillary distance, angle of deviation, and range of fusion.
This document discusses retinal correspondence and abnormal retinal correspondence. It defines retinal correspondence as the relationship between paired retinal visual cells in the two eyes that allows for single binocular vision. Abnormal retinal correspondence occurs when the fovea of one eye corresponds to an extrafoveal area in the other eye, resulting in eccentric fixation but maintained binocular vision. The document describes tests to assess normal versus abnormal retinal correspondence, including the Bagolini striated glasses test, red filter test, and Hering-Bielschowsky after-image test.
The term ‘‘aniseikonia” comes from the Greek words ‘‘an” (not) ‘‘is” (equal) & ‘‘eikon” (icon or image) so aniseikonia is a binocular condition in which the apparent sizes of the images seen with the two eyes are unequal.
Whenever refractive ametropias in the two eyes of a person are different (i.e., when there is an anisometropia), the corrected retinal images of the two eyes, and consequently the two visual images, differ in size.
This condition has been termed aniseikonia
Optical aniseikonia
Retinal aniseikonia
Cortical aniseikonia
This document discusses various theories and anomalies of accommodation. It begins by defining accommodation and related terms. It then discusses several theories of the accommodation mechanism, including Helmholtz's relaxation theory, Gullstrand's mechanical model, and Schachar's, Tsherning's, and Cotenary's theories. It also covers types of accommodation and anomalies such as presbyopia, insufficiency/ill-sustained accommodation, paralysis, excess accommodation, and spasm. Presbyopia is discussed in detail regarding pathophysiology, causes, symptoms, and treatment options like optical correction and surgery. Other anomalies are summarized briefly regarding their etiology, clinical features, and management.
Vergence eye movements allow for the convergence and divergence of the eyes to change the angle formed by the visual axes. The vergence system includes voluntary and reflexive components. Reflex vergence is composed of tonic, accommodative, proximal, and fusional vergence responses. Accommodative convergence is the vergence response stimulated by accommodation. The AC/A ratio represents the relationship between accommodation and convergence. Maintaining the proper balance between all the components of the vergence system is important for managing vergence and binocular vision problems.
This document discusses the evolution of technologies used to evaluate corneal astigmatism and irregularities. It summarizes several technologies including manual keratometry, video keratoscopy, topography, Orbscan, Pentacam, and IOL Master. Newer technologies like Pentacam and IOL Master provide more accurate and repeatable measurements of the cornea and lens compared to older methods. However, manual keratometry remains useful when budget is limited if performed carefully with calibration and multiple readings. Overall accuracy, affordability, and repeatability must be considered when selecting a technology for corneal evaluation.
This document discusses diplopia charting, which is used to diagnose ophthalmoplegia by recording double vision. It outlines the etiology, principles, objectives, procedure, interpretations and applications to specific cranial nerve palsies. Diplopia charting involves having the patient view a light source through colored lenses to indicate the position of double images in different gazes. This provides information to localize affected extraocular muscles and diagnose conditions like cranial nerve palsies. Precise documentation of findings from diplopia charting combined with patient history and exam can help identify neuro-ophthalmic pathologies.
Accommodation anomalies can occur due to various causes and present with different symptoms. Assessment involves dynamic retinoscopy and measuring accommodation amplitudes. Accommodative fatigue can result from overuse and be treated by correcting refractive errors and discussing visual hygiene. Presbyopia is age-related and treated with near vision correction. Other failures of accommodation include insufficiency, paralysis, spasm, and sustained accommodation, each with different etiologies, signs, and treatments.
The presentation presents some treatment modalities as regards AI.This is to keep you thinking more on how to approach a case of AI in terms of management.
Vergence refers to the simultaneous movement of the eyes in opposite directions to maintain binocular vision. There are different types of vergence including fusional vergence, proximal vergence, tonic vergence, and accommodative vergence. Vergence is measured through tests such as near point of convergence and AC/A ratio. Common vergence anomalies include convergence insufficiency, convergence excess, divergence insufficiency, and divergence excess, each characterized by specific symptoms and treatments.
Anisometropia refers to an unequal refractive power between the two eyes. It can be congenital or acquired. A difference of 1 diopter causes a 2% difference in retinal image size, which is generally well tolerated up to 2.5 diopters. Higher amounts may cause issues like amblyopia, strabismus, or diplopia. Treatment depends on the degree and includes glasses, contact lenses, or refractive surgery. For children, full refractive correction is usually prescribed to prevent amblyopia, while adults may be undercorrected to avoid diplopia. Managing anisometropic amblyopia involves full refractive correction, occlusion therapy if needed, and vision therapy.
Fixation disparity occurs when the visual axes of the eyes are not perfectly aligned on an object being fixated. It results in a small misalignment that falls within Panum's fusional area. Different types of fixation disparity include exo and eso disparities. Fixation disparity is a more useful measure of binocular vision status than phoria, as it can be measured under normal binocular viewing conditions, unlike phoria which requires dissociating the eyes. Fixation disparity curves provide information about the relationship between phoria and fixation disparity.
This document discusses the evaluation of strabismus. It begins by classifying strabismus and describing the axes of the eye. It then discusses the goals of a strabismus examination, which include establishing a cause, diagnosing amblyopia, measuring deviation, and assessing binocular sensory status. The document outlines various tests used in the sensory and motor evaluation of strabismus, including visual acuity tests, cover tests, versions and duction tests, and tests of stereopsis. It provides details on classifying deviations, measuring deviations, and evaluating binocular vision and sensory responses.
This document describes an orthoptic instrument called a haploscope. A haploscope is an optical device that presents different images to each eye, allowing examination of binocular vision. The haploscope described has adjustable components to measure fusion, stereopsis, deviations in different gazes, and more. It can be used for both diagnostic and therapeutic purposes in orthoptic treatment and management of conditions like strabismus and amblyopia.
- Presbyopia is the age-related loss of accommodation due to reduced elasticity of the lens and ciliary muscles. It starts in the 40s and complete loss of accommodation occurs by 50-60 years.
- Theories of accommodation include the Helmholtz theory of ciliary muscle contraction relaxing the zonules to allow lens curvature change, and the Schachar theory of reduced perilenticular space limiting ciliary muscle effect.
- Risk factors include occupation, geography, gender, medical conditions, and drugs. Treatment options include glasses, contact lenses, and various surgical procedures like LASIK, multifocal IOLs, and scleral expansion bands.
Perimetry by Pandian M, Dept of Physiology, DYPMC, KOP, MHPandian M
Introduction
Field of vision Vs binocular
Different types of Perimetry
Visual pathways
Procedure
Normal field of vision
Blind spot
Scotoma
Fields defects in lesions of visual pathway
Factors affecting F.V.
Precautions
Observation
Reference
Sensory adaptations, such as anomalous retinal correspondence (ARC) and suppression, develop in young children with strabismus to avoid diplopia and confusion. ARC involves a shift in spatial localization between the eyes' retinas such that images from non-corresponding retinal points appear fused. Tests for ARC produce varying results depending on the degree of sensory dissociation. While ARC is initially adaptive, it can become ingrained over time if the strabismus is not treated early in the visual development period from infancy to age 6 years. Suppression involves cortical inhibition of images from the deviating eye to prevent confusion, and its depth and extent can be measured using various tests involving filters, lenses, and stereosc
This document discusses spectacle refraction and how it relates to correcting refractive errors like myopia, hyperopia, and astigmatism. It defines spectacle refraction as the power of the lens needed to correct refractive errors at the spectacle plane. Myopia occurs when light focuses in front of the retina, and is corrected using concave lenses. Hyperopia is when light focuses behind the retina, corrected with convex lenses. Astigmatism is an irregular refraction that can be corrected using lenses, contacts, surgery, or lasers. The document also discusses how to calculate spectacle refraction from ocular refraction using vertex distance.
This document discusses anisometropia, which is when the total refraction of the two eyes is unequal. It can be congenital or acquired. There are several clinical types including simple, compound, and mixed anisometropia. Symptoms may include eye strain, headaches, and suppression of one eye. Diagnosis involves retinoscopy and tests of binocular vision like the Friend test and Worth's four-dot test. Treatment options include glasses, contact lenses, anisometropic spectacles, and refractive surgery depending on the degree of anisometropia.
The document summarizes several theories of accommodation, including Helmholtz's relaxation theory, Schachar's theory, and the catenary theory. It also discusses clinical assessment of accommodation and various anomalies such as insufficiency, excess, spasm, and infacility. Treatment options mentioned include spectacle correction, vision therapy exercises to stimulate or relax accommodation, and in rare cases, cycloplegic drugs.
The growth inhibitory effects and mechanism of aminoimidazole carboxamide ribonucleotide (AICAR), an AMP-dependent kinase (AMPK) activator, on the growth of uveal melanoma cell lines.
AMP-activated protein kinase (AMPK) is an enzyme that acts as a cellular energy sensor. It is activated by increases in the AMP:ATP ratio caused by metabolic stresses that deplete ATP. When activated, AMPK works to switch on catabolic pathways that generate ATP while switching off ATP-consuming processes like biosynthesis. AMPK activation improves blood glucose and lipid levels, making it a promising target for treating diabetes and other metabolic disorders. AMPK regulates glucose and lipid metabolism in the liver, skeletal muscle, pancreas and hypothalamus.
The optom faslu muhammed is a haploscopic device used to assess binocular vision. It consists of two tubes mounted on a base with a chin rest and forehead rest. Each tube contains a light source, slide carrier, reflecting mirror, and +6.50D eye piece. It is used to test various grades of binocular vision like simultaneous macular perception, fusion, and stereopsis using different slides. It can also be used to measure the inter-pupillary distance, angle of deviation, and range of fusion.
This document discusses retinal correspondence and abnormal retinal correspondence. It defines retinal correspondence as the relationship between paired retinal visual cells in the two eyes that allows for single binocular vision. Abnormal retinal correspondence occurs when the fovea of one eye corresponds to an extrafoveal area in the other eye, resulting in eccentric fixation but maintained binocular vision. The document describes tests to assess normal versus abnormal retinal correspondence, including the Bagolini striated glasses test, red filter test, and Hering-Bielschowsky after-image test.
The term ‘‘aniseikonia” comes from the Greek words ‘‘an” (not) ‘‘is” (equal) & ‘‘eikon” (icon or image) so aniseikonia is a binocular condition in which the apparent sizes of the images seen with the two eyes are unequal.
Whenever refractive ametropias in the two eyes of a person are different (i.e., when there is an anisometropia), the corrected retinal images of the two eyes, and consequently the two visual images, differ in size.
This condition has been termed aniseikonia
Optical aniseikonia
Retinal aniseikonia
Cortical aniseikonia
This document discusses various theories and anomalies of accommodation. It begins by defining accommodation and related terms. It then discusses several theories of the accommodation mechanism, including Helmholtz's relaxation theory, Gullstrand's mechanical model, and Schachar's, Tsherning's, and Cotenary's theories. It also covers types of accommodation and anomalies such as presbyopia, insufficiency/ill-sustained accommodation, paralysis, excess accommodation, and spasm. Presbyopia is discussed in detail regarding pathophysiology, causes, symptoms, and treatment options like optical correction and surgery. Other anomalies are summarized briefly regarding their etiology, clinical features, and management.
Vergence eye movements allow for the convergence and divergence of the eyes to change the angle formed by the visual axes. The vergence system includes voluntary and reflexive components. Reflex vergence is composed of tonic, accommodative, proximal, and fusional vergence responses. Accommodative convergence is the vergence response stimulated by accommodation. The AC/A ratio represents the relationship between accommodation and convergence. Maintaining the proper balance between all the components of the vergence system is important for managing vergence and binocular vision problems.
This document discusses the evolution of technologies used to evaluate corneal astigmatism and irregularities. It summarizes several technologies including manual keratometry, video keratoscopy, topography, Orbscan, Pentacam, and IOL Master. Newer technologies like Pentacam and IOL Master provide more accurate and repeatable measurements of the cornea and lens compared to older methods. However, manual keratometry remains useful when budget is limited if performed carefully with calibration and multiple readings. Overall accuracy, affordability, and repeatability must be considered when selecting a technology for corneal evaluation.
This document discusses diplopia charting, which is used to diagnose ophthalmoplegia by recording double vision. It outlines the etiology, principles, objectives, procedure, interpretations and applications to specific cranial nerve palsies. Diplopia charting involves having the patient view a light source through colored lenses to indicate the position of double images in different gazes. This provides information to localize affected extraocular muscles and diagnose conditions like cranial nerve palsies. Precise documentation of findings from diplopia charting combined with patient history and exam can help identify neuro-ophthalmic pathologies.
Accommodation anomalies can occur due to various causes and present with different symptoms. Assessment involves dynamic retinoscopy and measuring accommodation amplitudes. Accommodative fatigue can result from overuse and be treated by correcting refractive errors and discussing visual hygiene. Presbyopia is age-related and treated with near vision correction. Other failures of accommodation include insufficiency, paralysis, spasm, and sustained accommodation, each with different etiologies, signs, and treatments.
The presentation presents some treatment modalities as regards AI.This is to keep you thinking more on how to approach a case of AI in terms of management.
Vergence refers to the simultaneous movement of the eyes in opposite directions to maintain binocular vision. There are different types of vergence including fusional vergence, proximal vergence, tonic vergence, and accommodative vergence. Vergence is measured through tests such as near point of convergence and AC/A ratio. Common vergence anomalies include convergence insufficiency, convergence excess, divergence insufficiency, and divergence excess, each characterized by specific symptoms and treatments.
Anisometropia refers to an unequal refractive power between the two eyes. It can be congenital or acquired. A difference of 1 diopter causes a 2% difference in retinal image size, which is generally well tolerated up to 2.5 diopters. Higher amounts may cause issues like amblyopia, strabismus, or diplopia. Treatment depends on the degree and includes glasses, contact lenses, or refractive surgery. For children, full refractive correction is usually prescribed to prevent amblyopia, while adults may be undercorrected to avoid diplopia. Managing anisometropic amblyopia involves full refractive correction, occlusion therapy if needed, and vision therapy.
Fixation disparity occurs when the visual axes of the eyes are not perfectly aligned on an object being fixated. It results in a small misalignment that falls within Panum's fusional area. Different types of fixation disparity include exo and eso disparities. Fixation disparity is a more useful measure of binocular vision status than phoria, as it can be measured under normal binocular viewing conditions, unlike phoria which requires dissociating the eyes. Fixation disparity curves provide information about the relationship between phoria and fixation disparity.
This document discusses the evaluation of strabismus. It begins by classifying strabismus and describing the axes of the eye. It then discusses the goals of a strabismus examination, which include establishing a cause, diagnosing amblyopia, measuring deviation, and assessing binocular sensory status. The document outlines various tests used in the sensory and motor evaluation of strabismus, including visual acuity tests, cover tests, versions and duction tests, and tests of stereopsis. It provides details on classifying deviations, measuring deviations, and evaluating binocular vision and sensory responses.
This document describes an orthoptic instrument called a haploscope. A haploscope is an optical device that presents different images to each eye, allowing examination of binocular vision. The haploscope described has adjustable components to measure fusion, stereopsis, deviations in different gazes, and more. It can be used for both diagnostic and therapeutic purposes in orthoptic treatment and management of conditions like strabismus and amblyopia.
- Presbyopia is the age-related loss of accommodation due to reduced elasticity of the lens and ciliary muscles. It starts in the 40s and complete loss of accommodation occurs by 50-60 years.
- Theories of accommodation include the Helmholtz theory of ciliary muscle contraction relaxing the zonules to allow lens curvature change, and the Schachar theory of reduced perilenticular space limiting ciliary muscle effect.
- Risk factors include occupation, geography, gender, medical conditions, and drugs. Treatment options include glasses, contact lenses, and various surgical procedures like LASIK, multifocal IOLs, and scleral expansion bands.
Perimetry by Pandian M, Dept of Physiology, DYPMC, KOP, MHPandian M
Introduction
Field of vision Vs binocular
Different types of Perimetry
Visual pathways
Procedure
Normal field of vision
Blind spot
Scotoma
Fields defects in lesions of visual pathway
Factors affecting F.V.
Precautions
Observation
Reference
Sensory adaptations, such as anomalous retinal correspondence (ARC) and suppression, develop in young children with strabismus to avoid diplopia and confusion. ARC involves a shift in spatial localization between the eyes' retinas such that images from non-corresponding retinal points appear fused. Tests for ARC produce varying results depending on the degree of sensory dissociation. While ARC is initially adaptive, it can become ingrained over time if the strabismus is not treated early in the visual development period from infancy to age 6 years. Suppression involves cortical inhibition of images from the deviating eye to prevent confusion, and its depth and extent can be measured using various tests involving filters, lenses, and stereosc
This document discusses spectacle refraction and how it relates to correcting refractive errors like myopia, hyperopia, and astigmatism. It defines spectacle refraction as the power of the lens needed to correct refractive errors at the spectacle plane. Myopia occurs when light focuses in front of the retina, and is corrected using concave lenses. Hyperopia is when light focuses behind the retina, corrected with convex lenses. Astigmatism is an irregular refraction that can be corrected using lenses, contacts, surgery, or lasers. The document also discusses how to calculate spectacle refraction from ocular refraction using vertex distance.
This document discusses anisometropia, which is when the total refraction of the two eyes is unequal. It can be congenital or acquired. There are several clinical types including simple, compound, and mixed anisometropia. Symptoms may include eye strain, headaches, and suppression of one eye. Diagnosis involves retinoscopy and tests of binocular vision like the Friend test and Worth's four-dot test. Treatment options include glasses, contact lenses, anisometropic spectacles, and refractive surgery depending on the degree of anisometropia.
The document summarizes several theories of accommodation, including Helmholtz's relaxation theory, Schachar's theory, and the catenary theory. It also discusses clinical assessment of accommodation and various anomalies such as insufficiency, excess, spasm, and infacility. Treatment options mentioned include spectacle correction, vision therapy exercises to stimulate or relax accommodation, and in rare cases, cycloplegic drugs.
The growth inhibitory effects and mechanism of aminoimidazole carboxamide ribonucleotide (AICAR), an AMP-dependent kinase (AMPK) activator, on the growth of uveal melanoma cell lines.
AMP-activated protein kinase (AMPK) is an enzyme that acts as a cellular energy sensor. It is activated by increases in the AMP:ATP ratio caused by metabolic stresses that deplete ATP. When activated, AMPK works to switch on catabolic pathways that generate ATP while switching off ATP-consuming processes like biosynthesis. AMPK activation improves blood glucose and lipid levels, making it a promising target for treating diabetes and other metabolic disorders. AMPK regulates glucose and lipid metabolism in the liver, skeletal muscle, pancreas and hypothalamus.
Visual aids help reinforce spoken messages so audiences can better understand and retain information. They provide variety, illustrate concepts, and help explain how situations have changed over time. Examples include slides, videos, models, and diagrams. Visual aids help connect theory to practice, allowing learners to understand topics like what a furnace looks like in real life. Trainers must use visual aids appropriately to supplement rather than replace their message.
Maycol and Lilian are a musical duo that perform together, offering a variety of music styles from jazz to R&B, soul, funk, disco, and light rock. Maycol has a background as a music teacher and plays piano in a unique soul-funky style. Lilian has a sweet voice that ranges from Cher to Minnie Ripperton. For the past five years, they have performed throughout Europe and America in unique, high-profile venues for various audiences. Some of their past performances include for political figures and at concerts opening for well-known artists. They enjoy interacting with audiences and sharing their personalities.
The Arab Economic Forum is a major annual economic conference held in Beirut that brings together government leaders, business executives, and experts to discuss issues related to economic development in the Arab world. Over 19 years, it has grown to become the most influential recurring economic event in the region. The forum provides opportunities for high-level networking, exchanging ideas, and launching business initiatives. Prominent speakers from both public and private sectors discuss current economic trends and challenges facing the region.
Changing paradigms of corporate social responsibilitySorab Sadri
This document discusses changing paradigms of corporate social responsibility. It provides background and definitions of key concepts related to CSR such as corporate social performance, corporate citizenship, and the triple bottom line. The document outlines Thomas Kuhn's work on paradigm shifts and applies it to examining shifting elements of the CSR paradigm. It discusses varying definitions and approaches to CSR, including altruistic and strategic approaches. The altruistic view sees CSR as a moral duty regardless of profitability, while the strategic view sees CSR as a way for companies to gain competitive advantage.
Emma va a buscar un objecte perdut a la granja. Recorre tots els llocs on podria estar, com els corrals, els camps i els estables. Finalment el troba amagat sota una pila de palla.
Organizational culture can be defined as shared values and beliefs that guide employee behavior and decision-making. It plays a key role in directing actions towards organizational goals. An effective organizational culture (1) creates a framework for trust and transparency, (2) empowers managers through delegation while holding them accountable, and (3) provides clarity of vision, mission, and roles. Implementing such a "value-centered" culture requires planned HR interventions to disrupt the status quo and change the organization for improved effectiveness.
key elements to make the most out of enterprise mobility effortsSpace-O Technologies
Corporations are becoming more experienced in deploying and managing mobile applications across the enterprises. Are you wondering which enterprise mobility solution should you deploy to increase the ROI? Here are some key concerns that must be addressed while deploying enterprise mobility apps in the organization.
The document discusses scanning laser polarimetry (SLP), which uses a laser to measure the thickness of the retinal nerve fiber layer (RNFL) to aid in early glaucoma diagnosis. SLP works by measuring the birefringence and phase shift of laser light passing through the RNFL. A scanning laser polarimeter called GDx VCC is described, which takes RNFL scans and analyzes parameters like thickness averages, deviation maps, and nerve fiber indicators to detect glaucomatous changes. Key advantages are that it is non-invasive and allows comparison to normative databases, but limitations include sensitivity to other ocular conditions and limited use in advanced glaucoma.
1) The study examined clinical measurements and neural changes associated with vision therapy in adults with convergence insufficiency.
2) Four subjects with convergence insufficiency underwent 18 hours of vision therapy. Clinical measurements improved and neural activity increased in areas related to vergence eye movements.
3) Convergence peak velocity was slower in subjects with convergence insufficiency compared to controls, but increased after vision therapy, suggesting therapy can improve underlying neurophysiology.
1) The study examined clinical measurements and neural changes associated with vision therapy in adults with convergence insufficiency.
2) At baseline, adults with convergence insufficiency had slower convergence eye movements compared to controls.
3) After 18 hours of vision therapy, the adults with convergence insufficiency showed improvements in clinical measurements of nearpoint of convergence and fusional vergence, as well as increased cortical activity and faster convergence eye movements.
1) The study examined clinical measurements and neural changes associated with vision therapy in adults with convergence insufficiency.
2) Convergence peak velocities were slower in subjects with convergence insufficiency compared to controls, which may contribute to asthenopic complaints.
3) Subjects underwent 18 hours of vision therapy. Several clinical measurements, including nearpoint of convergence and positive fusional vergence, improved significantly after therapy. Neural activity in frontal and cerebellar regions also increased significantly.
1) The study examined clinical measurements and neural changes associated with vision therapy in adults with convergence insufficiency.
2) At baseline, adults with convergence insufficiency had slower convergence eye movements compared to controls.
3) After 18 hours of vision therapy, the adults with convergence insufficiency showed improvements in clinical measurements of nearpoint of convergence and fusional vergence, as well as increased cortical activity and faster convergence eye movements.
Electrophysiological assessment of optic neuritis: is there still a roleClare Fraser
Visual evoked potentials were once in the diagnostic criteria for Multiple Sclerosis, but have been left off the most recent criteria. However, there are newer techniques available which are still invaluable in the diagnosis of optic neuritis and its common mimics.
Positron-emission tomography studies of cross-modality inhibition in selectiv...Dr Brendan O'Sullivan
Published in 1994, this groundbreaking paper featured the research of Professor Per Roland, Professor Ryuta Kawashima (of “Brain Training” fame) and Professor Brendan O’ Sullivan.
This landmark research was the first to prove in human brain imaging studies that visual attention is impaired when we do other attention-competing tasks such as manual tasks such as using mobile phones while driving.
There is generally reduced retinal sensitivity in patients with pathological myopia. This study evaluated inter-ocular asymmetry of macular sensitivity between eyes in 36 such patients using microperimetry. It found statistically significant differences in sensitivity between males and females in the central and second rings. The physiological range of inter-ocular asymmetry for central macular sensitivity was within 7.28 dB. There was a negative correlation between retinal sensitivity and spherical equivalent, indicating worse sensitivity with higher myopia. The study provides reference values for evaluating abnormal inter-ocular differences in retinal function for patients with pathological myopia.
Aniseikonia is an anomaly of binocular vision where the ocular images are unequal in size or shape. It becomes clinically significant when a patient has difficulty combining images of different sizes or shapes into a single perception. Aniseikonia can be static, where images are perceived as different sizes for fixed gaze positions, or dynamic, where different eye rotation is needed to fixate on the same point. It is classified as optical, retinal, or cortical depending on its underlying cause. Aniseikonia is commonly measured using computerized tests and managed using specialized contact lenses, occlusion therapies, or prism corrections.
This study examined the effects of aging and Alzheimer's disease on cortical visual processing using an optic flow heading discrimination task with valid and invalid pre-cues in young normal, older normal, and Alzheimer's disease participant groups. Event-related potentials showed that aging is associated with increased N200 amplitude and decreased P300 amplitude and coherence, while Alzheimer's disease shows decreased N200 amplitude and coherence and loss of the N2b component. These results reveal differences in attentional processing and responses between aging and Alzheimer's disease.
[KHBM] Application of network analysis based on cortical thickness to obsessi...Seung-Goo Kim
This was presented at The Biannual Meeting of Korean Society of Human Brain Mapping (KHBM), Seoul, Korea (Nov 2011). It was selected for the Excellent Oral Award.
This document summarizes a technique called Laser Blended Vision for treating presbyopia using a customized laser procedure. It operates through 8 mechanisms including monovision, increased depth of field, and neural processing in the brain. Clinical results show high patient satisfaction and visual outcomes for distance, intermediate, and near vision without glasses for patients with myopia, hyperopia, and emmetropia. Complications were low.
Tomographic fundus features in Pseudoxanthoma Elasticum Abdallah Ellabban
This study analyzed optical coherence tomography (OCT) scans of 52 eyes from 27 patients with pseudoxanthoma elasticum (PXE) and compared features between those with choroidal neovascularization (CNV) secondary to angioid streaks (AS) vs CNV secondary to age-related macular degeneration (AMD). Unique lesions were more common in PXE patients, including outer retinal tubulation (ORT) seen in 70.5% of eyes with CNV secondary to AS vs 34.1% of AMD eyes, and Bruch's membrane undulation seen in 70.8% vs 11.4% respectively. ORT appeared as round or ovoid structures beneath the outer plexiform layer.
This study measured binocular balance in people with normal vision by quantifying their sensitivity to coherent motion presented separately to each eye. The study found that:
1) Most subjects showed balanced or weakly imbalanced sensitivity between the eyes, but some showed strong imbalances.
2) The degree of imbalance, or "balance point", was affected by mismatches in mean luminance between the eyes, suggesting inhibitory circuits underlying eye dominance are located precortically.
3) Changing the interocular contrast ratio allowed quantification of the contrast required for balanced sensitivity, referred to as the balance point.
Optical Coherence Tomography in Multiple Sclerosis: a Structural & Functional...Manal AlRomeih
This document analyzes optical coherence tomography (OCT) as a potential biomarker for central nervous system degeneration in multiple sclerosis (MS). OCT and retinal nerve fiber layer (RNFL) thickness showed high sensitivity in detecting neurodegeneration in MS patients, correlating with visual functions and disability levels. RNFL thickness was significantly reduced in MS patients, especially those with optic neuritis, and correlated with disease severity measures. OCT may thus serve as a valuable tool to quantify neurodegeneration in MS for use in clinical trials, patient monitoring, and treatment assessment by providing a window into central nervous system changes.
This study evaluated the predictive accuracy of the SRK-2 formula for calculating intraocular lens (IOL) power in 274 eyes undergoing phacoemulsification cataract surgery in Sri Lanka. The mean age was 65.3 years and axial length ranged from 22-26mm. The SRK-2 formula predicted post-operative refractive errors with a mean error of -0.300±0.145D. The actual achieved refractive error was -0.220±0.732D, showing a slight hyperopic shift. 79% of patients had 6/6 vision 7 days post-op. The study concluded that the SRK-2 formula provides a good option for predicting refractive outcomes in eyes with medium axial
The document discusses two imaging techniques used to detect glaucoma - HRT (Heidelberg Retinal Tomography) and GDx (scanning laser polarimetry). HRT uses confocal scanning laser ophthalmoscopy to generate a 3D topographic image of the optic disc and retinal nerve fiber layer. GDx measures the retinal nerve fiber layer thickness around the optic disc using scanning laser polarimetry, which analyzes the polarization of light passing through the birefringent retinal nerve fiber layer. Both provide objective measures of the optic disc and retinal nerve fiber layer but have limitations such as dependency on accurate contour line placement for HRT.
Optic Neuritis and OCT in Multiple Sclerosis neurophq8
This talk was given in the MS preceptorship day in Dasman Institute . It discusses the advances in the diagnosis of optic neuritis and value of optical coherence tomography in MS patients.