Ophthalmology orbital anatomy ppt. Introduction to Orbit, its anatomy, muscles, Blood supply, its nerve supply and clinical co-relations.

1. ANATOMY OF EYELID
PRESENTED BY:
Dr. Rahul Gupta
1ST Year Resident
Dept. Ophthalmology
Date: 27th july.2023

2. CONTENT
• INTRODUCTION
• EMBRYOLOGY
• GROSS ANATOMY
• LAYERS OF EYELID
• GLANDS OF EYELID
• NERVE, VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
• CLINICAL CORRELATION
• PHYSIOLOGY OF EYELID MOVEMENTS

3. Introduction
o Mobile, flexible, multilamellar structures that cover the
globe anteriorly
o Helps to keep the corneas moist, and protect against
injury and excessive light,
o Regulate the amount of light reaching the retina.
o The lids are essential for distribution and drainage of
the tears

4. Embryology
• Derived from surface ectoderm
• The upper eyelids are formed
from the frontonasal process
• The lower eyelids are formed
from the maxillary process

5. Structure developed Time of gestation
Appearance of the eyelid fold marks the
beginning
6 or 7 week of gestation
Eyelid fusion 8 to 10 weeks gestation.
Development of eyelid structures 3 to 4 months gestation.
Eyelid dysjunction 5 to 6 months gestation

7. Clinical Correlation
Congenital eyelid disorders:
a) Cryptophthalmos:
• Failure of development of eyelid structures
• Skin continues from forehead to cheek and
inner side is adherent to cornea
b) Coloboma of eyelid:
Usually occurs in upper eyelid
c) Ankyloblepheron:
Fusion of part or all of eyelid margin.
In ankyloblepheron filiforme adnatum eyelids
are connected via fine strands

8. d) Congenital Ectropion:
Outward deviation of margin …common in
lower lid…mainly due to vertical deficiency
of skin
e) Congenital Entropion:
Inward turing of eyelid…unlike
epiblepheron doesn’t resolve itself
f) Epiblepheron:
Horizontal fold of skin adjacent to either
upper or lower lid margin (common)…can
turn lashes inward against cornea
Cornea during early life can tolerate this
condition
Usually resolves spontaneously

9. g) Epicanthus:
Crescent shaped fold of skin running vertically
between eyelids and overlying inner canthus
 Epicanthus tarsalis: fold most prominent in
Upper lid
 Epicanthus inversus: fold prominent in lower
lid
 Epicanthus palpebralis: fold equally distributed
in UL and LL
 Epicanthus supraciliaris: fold arises from
eyebrow and terminates over lacrimal sac
h) Blepherophimosis syndrome:
Blepherophimosis + Epicanthus inversus +
Telecanthus + Ptosis
Palpebral fissure is shortened horizontally and
vertically(Blepherophimosis) with poor levator
function and no eyelid fold

10. GROSS ANATOMY
1. EXTENT AND POSITION OF
EYELIDS
• upper eyelid: extends over
the orbital margin to the
eyebrow above
• Lower eyelid: more smoothly
into the cheek, where
nasojugal and malar sulci may
limit it
• At nasojugal sulcus a band of
connective tissue passes
between orbicularis oculi and
levator labii superioris

11. The upper lid
• Most mobile
• In forward gaze the upper lid
just overlaps the cornea (1/6th)
• upper eyelid margin at 1.5 – 2
mm below the superior
corneal limbus
The lower lid
• Just touches the cornea in
forward gaze
• lower eyelid margin at inferior
corneal limbus

12. 2. PARTS
 Orbital part
 Tarsal part
3. CANTHUS
Medial canthus Lateral canthus
a) more obtuse
b) Inferior lower rim: horizontal & a
superior rim: sloping infero-medially
c) Medial canthus is separated from globe by
the tear lake In this area there is caruncle
and plica semilunaris
a) acute, about 30-40 deg with the lids wide
open.
b) 5-7 mm medial to the orbital margin and
1 cm from the frontozygomatic suture
c) lateral canthus is in contact with the
globe.
d) With the lids open, the lateral canthus is
about 2 mm above the medial canthus

13. • CARUNCLE- Modified skin
containing sebaceous glands and
hairs
• PLICA SEMILUNARIS-
Highly vascular crescent shaped
fold of conjunctiva .Vestigial
structure analogous to nictitating
membrane of animals

14. EYELID MARGINS
 2mm in width
 Each lid margin divided into 2 parts by lacrimal papilla
 Lacrimal portion medially : devoid of lashes/glands and
 Ciliary portion laterally:
 rounded anterior, sharp posterior border and intermarginal strip
 grey line(referred to as the muscle of Riolan and represents the
pretarsal orbicularis muscle): junction of skin and conjunctiva divides
intermarginal strip into ant.stripbearing lashes and
postmeibomian glands

16. Lacrimal portion medially:
lacrimal punctum (upper & lower) exits at the summit of each
lacrimal papilla
punctum divides the lid margin into medial lacrimal portion and
the lateral ciliary portion.
upper punctum is more medial than lower punctum;

17. • EYELASHES
• Approximately 100 to 150 cilia -upper eyelid, and 50 to 75 cilia -
lower eyelid., arranged in two to three rows
• Glands of Zeis and Moll open into each hair follicle
• Dense plexus of nerves and vesssels around follicle – exquisite
tactile sensibility

18. 6.PALPEBRAL APERTURE OR FISSURE
Diameter At birth Adult
Horizontal 18-21mm 28-30mm
Vertical 8mm 9-11mm

19. Trichiasis
- Eyelashes are misdirected
and grow inwards towards the eye
Distichiasis
- Abnormal growth of lashes from
the orifices of the meibomian glands
Clinical Correlation

20. Madarosis
- Partial or complete loss of
eye lashes, may be congenital
or due to infection.
Poliosis
- Whitening of eye lashes
Trichomegaly
- Increase in length , curling,
pigmentation or thickness of
eyelashes.

21. Layers Of The Eyelids
1. Skin & subcutaneous
areolar tissue
2. Muscles of protraction
3. Orbital septum
4. Orbital fat
5.Muscles of retraction
6. Tarsus
7. Conjunctiva

22. Skin
o Thinner than any other part of the body
o Thinnest skin in the medial upper eyelid almost
transparent
o Contains the usual adnexal structures: fine hairs,
sebaceous & sweat glands

23. o Nasal skin is shinier, smoother
and greasier, devoid of hair.
• well provided with unicellular
sebaceous glands, hence
xanthelesma develops on the
nasal side.
o Sweat glands - small
numerous , more on the
lateral aspect of the eye lid.

24. Layers of the skin
• Epidermis: It consist of 4 layers of keratin producing cells;
o stratum corneum
o stratum granulosum
o Stratum spinosum
o stratum basale
• Dermis :
• Thin layer of dense
connective tissue with rich
network elastic Fibres, blood
vessels, lymphatics and nerves.

25. Subcutaneous Areolar Tissue:
o loose connective tissue arrangement
o elastic in nature.
o no fat
o Applied Anatomy - fluid from oedema or haemorrhage
rapidly engorges the loose subcutaneous eyelid tissue &
produce dramatic eyelid swelling and recovers rapidly as
well.

26. The Orbicularis Oculi Muscle
o complex striated muscle
sheet
o divided anatomically
into three contiguous
parts –
o Orbital
o Palpebral -
• Preseptal
• Pretarsal

27. • Orbital Part:
• Orbital orbicularis portion extends
superiorly to the eyebrow, where it
interdigitates with the frontalis and the
corrugator superciliaris muscles.
• Medially, it extends from the
supraorbital notch in a curvilinear
fashion over the side of the nose,
inferiorly to the infraorbital foramen.
• It continues along the infraorbital
margin.
• Laterally, it extends to the temporalis
muscle.
These thick course fibers play an
important role in voluntary lid closure
(winking) and forced eyelid closure.

28. • Pretarsal part
• Superficial origin-Medial canthal
tendon
• Deep origin – posterior lacrimal crest
Deep heads fuse near common
canaliculus to form Horners muscle
(Pars lacrimalis)
• Contraction of which draws the
eyelids medially and posteriorly. The
resulting lateral pull creates a
negative pressure in the lacrimal sac
and draws the tears from the
canaliculi into the sac.
• Laterally attaches at lateral canthal
tendon

29. • Preseptal part:
• The medial origin : from two heads
 the deep: lacrimal sac and lacrimal
fascia
 the superficial heads: anterior rim
of the medial canthal ligament
 Laterally, inserts directly onto
Whitnall's lateral orbital tubercle 3 to
4 mm deep to the lateral palpebral
raphe.

30. • Closes the eyelids
• Contraction of these fibers aid in the lacrimal pump
mechanism.
Function of eyelid

31. Muscle Of Riolan
o Small bundle of striated muscle
fibers at the eyelid margin
o Extension of orbicularis oculi
fibers and contributes
to keeping the lids in close
apposition.

32. Horner’s Muscle
o Prominent bundle of fibers, formed by fusion of the deep
heads of the pretarsal orbicularis
o Runs just behind the posterior limb of the canthal tendon
o Insertion - Posterior lacrimal crest
o Functions - Helps to maintain the posterior position of
the canthal angle
• Tightens the eyelids against the globe during eyelid
closure
• Aid in the lacrimal pump mechanism

33. Orbital Septum
 Thin, fibrous, multi layered membrane

34. • Upper Lid
o Arcus marginalis(Condensation of
periosteum of forehead with the
periorbita of orbit at the
supraorbital rim)
o Fat within the fibroadipose layer
• Anterior to the orbital septum
• Mistaken for the
preaponeurotic fat pad during
eyelid surgery

35. Lower eyelid
• Attaches with Inferior orbital
rim
• Condensation of periosteum &
periorbita
• Continues anteriorly and
superiorly
o 4-5 mm below inferior tarsus
• Joins with lower eyelid
retractors
• Inserts on lower border of
inferior tarsus

36. o Applied Anatomy:
• Eyelid is a barrier to orbital fat / extravasation of blood /
spread of infection
• With age, orbital septum weakens  orbital fat herniates
 Dermatochalasis

37. The Preaponeurotic Fat
o anterior extensions of
extraconal orbital fat
o in the upper eyelid -
medial & central fat
pockets
o in the lower eyelid -
medial, central &
lateral fat pockets

38. Applied Anatomy –
o surgically important
landmarks (immediately
anterior to the major
eyelid retractors)
o Excessive traction
during Lower lid
surgery transmitted
deeper into the orbit
• Intraoperative or
postoperative orbital
hemorrhage

39. The Eyelid Retractors:

40. • LEVATOR PALPEBRAE SUPERIORIS
• originates from the lesser wing of the sphenoid bone,
superolateral to the optic foramen
• As the triangular levator muscle courses anteriorly in the orbit
from its origin, it is composed of striated muscle. The average
length of the muscular portion of the levator is 36 mm.
• At the level of the globe, fans out and thins as the whitish gray
superior transverse ligament of Whitnall or Whitnall's
ligament.
• forming the more vertical levator aponeurosis(18 mm width)..

41. • The medial horn of the levator attaches to the medial
canthal ligament. Its attachment is looser and more ill-
defined
• The lateral horn of the levators splits the lacrimal gland
into the larger orbital lobe and the smaller palpebral lobe
Attaches to the lateral orbital tubercle by the lateral canthal
tendon

43. Supratarsal Muscle Of Muller
- The sympathetic accessory retractor of upper eyelid
modulates the position of the upper and lower eyelids
when the eye is open.
Origin - undersurface of the levator muscle, just anterior to
Whitnall’s ligament
Insertion - anterior edge of the superior tarsal border

44. Capsulopalpebral Fascia
- fibrous extension arises from the inferior rectus muscle
- Capsulopalpebral head splits to surround the inferior oblique muscle.
- Capsulopalpebral fascia
- Inferior tarsal muscle
The two layers fuse anterior to the inferior oblique muscle to form a
dense fibrous structure termed Lockwood's suspensory ligament of
the globe
The outer fibers of the capsulopalpebral fascia fuse with the inner
fibers of the inferior orbital septum 4 to 5 mm below the inferior
tarsus and together advance as a single layer to insert on the inferior
border of the inferior tarsus

46. The Eyelid Retractors
- The upper eyelid has a maximal excursion of about 15 mm
without participation of the frontalis muscle.
- The lower eyelid has maximum excursion of about 5 mm
from up gaze to down
- The width of the palpebral fissure is determined by the
level of tonic activity in the levator palpebrae superioris and
the sympathetically innervated Müller’s muscle.

47. Tarsal plate
• 29-30mm long,1 mm thick
• Height
o 10-12 mm Upper lid
o 4-5 mm Lower lid
• Thickened fibrous connective tissue
• Structural support to eyelids
• Medially and laterally
o Connected to orbital margins by
ligamentous fibrous tissue
• Tarsal ( Meibomian gland ) within the
tarsal plate

48. The Conjunctiva
- Transparent vascularized membrane
covered by a non-keratinized epithelium
that lines the posterior surface of the
eyelids (palpebral conjunctiva)and the
anterior surface of the globe (bulbar
conjunctiva).
- Firmly adherent to the tarsus, for free
mobility.
- Small accessory lacrimal glands (Glands of
Krause & Wolfring) are located within the
submucous connective tissue

49. Glands
• Meibomian glands
• Glands of Zeis
• Glands of Moll
• Glands of Wolfring
• Glands of Krause

50. Glands of the Eye & Adnexa
Glands Location Secretion Content
Lacrimal Orbital Exocrine Aqueous
Sweat Gland Palpebral Exocrine Aqueous
Accessory Lacrimal Plica, Caruncle Exocrine Aqueous
Krause Eyelid Exocrine Aqueous
Wolfring Eyelid Exocrine Aqueous
Meibomian Tarsus Holocrine Oily
Zeis Follicle of cilia
Eyelid, Caruncle
Holocrine Oily
Moll Eyelid Eccrine Sweat
Goblet Cell Conjuctiva
Caruncle, Plica
Holocrine Mucus
Mucus

51. Meibomian Glands
o Multilobulated holocrine-
secreting sebaceous glands
within each tarsus
o Oriented vertically
o with central ductule that opens
onto the eyelid margin posterior
to the gray line.
o 30-40 no. in upper eyelid & 20-
30 no. in lower eyelid

52. o It produces sebum - oily material that forms the
lipid layer of the precorneal tear film
o Functions:
• Retards evaporation of the aqueous
component of the tear fluid
• Hydrophobic barrier at the margin of
the eyelid, preventing spillage of tears
at the lid margin.

53. Nerve Supply To The Eyelid
Motor Nerve Supply:
• Motor nerves to the
orbicularis oculi muscle - facial
nerve (temporal & zygomatic
branches)
• Motor nerve to the levator
palpebrae superioris -Superior
division of oculomotor nerve
• Motor nerve to the Müller
muscle - sympathetic nervous
system

54. Nerve Supply To The Eyelids
Sensory Nerve Supply:
Ophthalmic & maxillary divisions
of the trigeminal nerve
• Upper eyelid - supraorbital,
supratrochlear & lacrimal
nerves (ophthalmic division)
• lateral portion of upper
eyelid – zygomatico-
temporal branch of the
maxillary nerve
• extreme medial portion of
both upper & lower eyelid -
infratrochlear nerve

55. Sensory Nerve Supply continued:
lower eyelid - infraorbital nerve (maxillary division)

56.  Marginal Arcade
 Submuscular plane
 In front of tarsal plate
 3-4 mm from lid margin
 Lacrimal Artery
 Lateral Palpebral Artery
 Dorsal Nasal Artery
 Medial Palpebral Artery
 Peripheral Arcade
 Superior branch of Medial
Palpebral Artery
 Upper border of Tarsus
Arterial Supply

57. Venous Supply To The Eyelids
Venous Drainage Divided into pretarsal
and postarsal
 - Pretarsal which opens into
subcutaneous veins and futher drains
into angular vein medially and
superficial temporal vein laterally.
 - Postarsal drainage is into orbital
veins, then to ophthalmic vein and to
cavernous sinus.

58. Lymphatic Drainage
restricted to the region anterior to the orbital
septum
o lateral most of the upper eyelid drains into
pre-auricular node and small part of the
middle of the upper eyelid and the inner
half of the lower eyelid drains into the
submandibular lymph nodes.
o Preauricular and deep parotid nodes
eventually empty into the deep cervical
nodes near the internal jugular vein.
o submandibular nodes eventually empties
into the internal jugular vein.

59.  External Hordeolum (Common Stye)
 Localized suppurative inflammation of gland of
Zeis and glands of Moll’s at lid margin at ciliary
follicle.
Clinical Aspects

60.  Internal Hordeolum( Meibomian stye)
 Internal Hordeolum is a suppurative inflammation of
meibomian gland associated with the blockage of the
duct.

61.  Chalazion
 Chronic granulomatous inflammation of meibomian gland or
sometimes Zeis glands caused by retained sebaceous
secretions
 Ocurrs secondary to obstruction of the gland duct.
 More common in upper eyelid appearing as hard, immobile,
painless, roundish lump.

62.  Blepharitis
 Blepharitis is subacute or chronic inflammation of lid
margin occurring as true inflammation.
 Bilateral and often misdiagnosed as conjunctivitis
 Types:
 Anterior Blepharitis
 Affects the base of eyelashes and may be Staphylococcal,
Seborrhoeic or parasitic.
 Staphylococcal:
 In case of Staphylococcal – Red eyes and peripheral
corneal infiltrates (more common in atopic dermatitis)
 Common cause of ocular discomfort and irritation

63.  Yellow crusts are seen at the root of cilia
 Small ulcers which bleed easily on removal of clusters

64.  Seborrheic Blepharitis
 Primary anterior blepharitis with some posterior spill over
 Usually associated with seborrhea of scalp(dandruff)
 Accumulation of white dandruff like scales on lid margin

65.  Parasitic Blepharitis
 Due to crab louse very rarely to head louse
 Presence of nits at the lid margin and at roots of eyelashes
 Conjunctival congestion may be seen on long standing

66.  Meibomitis ( Posterior Blepharitis)
 Inflammation and obstruction of meibomian glands.
Characterized by diffuse thickening of posterior border
of lid margin which becomes rounded.

67.  Involutional entropion:
Age related inward rolling of eyelashes mainly affecting
lower lid
Constant rubbing on the cornea cause irritation,
corneal punctate epithelial erosions and sometimes
ulceration
Entropion

68. Cicatricial entropion
Scarring of the palpebral conjunctiva can rotate the
upper or lower lid margin towards the globe
Causes include cicatricial conjunctivitis, trachoma, trauma
and chemical injuries

69.  Involutional ectropion
Age related outward rolling of eyelid margin mainly
affecting lower lid
Causes epiphora and on long standing become
chronically inflamed and keratinized
Ectropion

70. Cicatricial ectropion
Caused by scarring or contracture of the skin and
underlying tissues which pulls the eyelids away from the
globe.
Paralytic ectropion
Caused by ipsilateral facial nerve palsy
Associated with retraction of upper and lower lids an
brow ptosis
Mechanical ectropion
Caused by tumors on or near lid margin that
mechanically evert the lid

71.  Incomplete closure of the palpabral aperture when attempt is
made to close the eyes voluntarily.
 Occurs due to paralysis of orbicularis oculi muscle, cicatricial
contraction, symblepharon, severe ectropion, proptosis etc.
Lagopthalmos

72.  It is the involuntary, sustained and forceful closure of the
eyelids.
Occurs in 2 forms:
1. Essential (Spontaneous) blepharospasm
2. Reflex blepharospasm.
Blepharospasm

73.  It is a partial or complete adhesion of the palpebral
conjunctiva of the eyelid to the bulbar conjunctiva of the
eyeball.
Symblepharon

74. Ptosis
• Abnormal Drooping of the upper eyelid is called ptosis.
• Normally, upper lid covers about upper one-sixth of the
cornea, that is 2mm. So ptosis cover more than 2mm.
• TYPES:
1. Congenital Ptosis;
- It is associated with congenital weakness
(maldevelopment) of Levator palpebral Superioris muscle.
2. Acquired Ptosis;
- Depending upon cause it can further be:
a. Neurogenic Ptosis
b. Acquired myogenic Ptosis

75. c. Aponeurotic Ptosis
d. Mechanical Ptosis

76. PHYSIOLOGY OF EYELIDS MOVEMENT
• Basically Opening and closing movements, however
depending on mechanics and neural control:
a) Blinking
b) Winking
c) Peering
d) Forceful closure

77. OPENING MOVEMENTS;
Muscles concerned:
a)Upper lid
i. LPS( primary elevator)
ii. Frontalis (accessory elevator)
iii. Superior palpebral muscle of Muller
b)Lower lid
No true counterpart of LPS present .
Opening depends on:
i. Elastic recoil of lower lid tissues
ii. Traction exerted by attachment of IR to inferior tarsus and
inferior palpebral muscle of Muller

78. • Opening movements are b/l symmetrical in direction and
amplitude. However it can be voluntarily inhibited on one side
 Levator muscle of both eyes act as Yoke muscles (Thus follow
Herings law of equal innervation)
 In U/L congenital ptosis, lid on unaffected side may be
retracted (based on Hering's law), to elevate the ptotic lid.
 Levator and Orbicularis however follow Sherrington's law of
reciprocal innervation.
 When levator receives maximum innervation during eye
opening orbicularis receives minimum innervation and vice
versa.

79. • Dynamics
As upper eyelid begins to move upward from closed position a
tremor(0.2 to 0.3mm in amplitude )is present
Upper lid moves vertically upward while lower lid moves laterally
in horizontal direction
Overshoots of opening followed by small recovery is frequently
seen

80. CLOSING MOVEMENTS
Muscle concerned:
• Orbicularis oculi….7th CN
• Although it is a single muscle , physiologically its 3 regions act as 3
independent muscles.
• 3 functional units of orbicularis are:
a) Pretarsal fibers: respond in spontaneous blinking and tactile corneal
reflex
b) Preseptal fibers: respond in voluntary blinking and sustained activity
c) Those responding in forceful closure of lids which include all 3
regions: pretarsal, preseptal and orbital fibers

81. During closing movements:
• Upper lid moves down vertically while lower lid moves
medially (horizontal)
• Movement of lower lid begins 10-20 msec before upper lid
• Gravity does not play a role in downward movement of upper
lid(speed same irrespective of head position)

82. PEERING
• Act of looking at something with great interest
• Upper lid moves down by 2.5 mm and medially by 1 mm
• Movement of lower lid begins 200msec before that of upper lid
(similar as in closing movement)
• Downward movement of upper lid in peering …mechanism
unclear
• Its found that relaxation phase of peering is initiated by
decrease in tone of orbicularis …and the lids then come in
normal position

83. BLINKING
Coordinated opening and closing movements of eyelids
Complete blink:
• begins in alert open position
• reaches halfway point when upper and lower lids appose each
other along atleast one half of their ciliary margins.
• Ends when upper and lower lids return to starting alert position
Blinking:
i. Voluntary
ii. Involuntary(spontaneous & reflex)

84. SPONTANEOUS BLINKING
• Without external stimulus
• Does not occur or infrequent during early months of
life(corneal dryness doesn’t occur)
• Also present in blind people (retinal stimulation is not
required)
Functions
• Redistribution of tear film
• Protection
• Rest for EOM(blinking allows momentary upturning of
eyes=analogous to position of eyes during sleep)

85. • Blink rate=12-20 / min
• Duration of blink < 300 msec
• Spontaneous blink doesn't produce discontinuation of vision
despite vision is interrupted for a fraction of second

86. REFLEX BLINKING
1) Tactile reflex blinking:
Sudden unexpected touch to cornea, conjunctiva, eyelash , eye
brow or lids
Blink response arising from corneal touch is nociceptive,
polysynaptic brainstem reflex
B/L response although only 1 cornea is touched
Begins 5 msec before on the ipsilateral side than contralateral side
Afferent pathway: 5th CN
Efferent pathway: 7th CN

87. 2) OPTIC REFLEX BLINKING
a) Dazzle reflex: Produced by shining bright light into eye
Subcortical so it may be lost in mesencephalic lesion
b) Menace reflex: Unexpected object coming to near field of vision
Cortical
(cortical lesions: menace reflex lost….corneal tactile and Dazzle
+nt)

88. 3) AUDITORY REFLEX BLINKING
Afferent: 8th CN
Efferent:7th CN
4) Stretch type stimulus reflex blinking:
When orbicularis is stimulated by stretch type stimulus(tap or blow)
Electrical activity in orbicularis in this type of reflex of 2 types:
a) Fast proprioceptive component…arises from stimulation of
stretch receptors in orbicularis..this is a segmental reaction
…doesn’t require interneuron between afferent and efferent
fibers
b) Nociceptive component: has polysynaptic pathway like tactile
reflex

89. Neural control of eyelid movements
Opening movements:
1) Volunatry eyelid opening movements:
Controlled by frontal eyefield area in frontal
cortex
Stimulation of this area results b/l eyebrow
elevation and eye opening
2) Involuntary eyelid opening movements:
Controlled by occipital motor area which
sends signals to frontal eye field area
3)Fine control of levator tone:
Extrapyramidal function

90. Closing movements:
1) Voluntary closing movements:
controlled by area 4 (facial region of
precentral motor cortex)
2)Spontaneous and reflex blinking:
Arise in subcortical centre and regarded as
extrapyramidal movements
END

91. References
• OPHTHALMOLOGY ANATOMY AND PHYSIOLOGY OF EYE
KHURANA ; Author Khurana A. K Edition: 3rd
• AMERICAN ACADEMY OF OPHTHALMOLOGY online
resources
• KANSKI’S CLINICAL OPHTHALMOLOGY; A SYSTEMIC
APPROACH- NINTH EDITION