animals eyelid anatomy physiology & diseases

1. Saurabh Gupta
VHK-1435

2. Skin:
 It is typically thin& loosely adherent to the underlying
tissue to facilitate movement.
 Muscles:
 Orbicularis occuli muscle: closure of palpebral
aperture.
 Superciliaris muscle: helps to elevate medial
upper lid.
 Retractor angularis oculi muscle: draws the
lateral canthus laterally.
 Sphincter colli profundus pars palpebralis
depresses the lower lid.
 Levator palpebrae superioris helps to elevates
the upper eyelid.
 Muller’s muscle to keeps lid & 3rd eyelid retracted.

3. Nerves
 Sensory innervation by trigeminal nerve.
 Motor innervation is by
1. Occulomotor nerve
2. Facial nerve
Blood vessels
 Superficial temporal artery
 Malar artery, supplies to third eyelid & eyelid.
 Angularis oculi vein
 Lid margins
 Cilia, are the tactile,present near the margin of upper lid in
dogs horses cattle etc.,
 Lid trough/furrow receives the secretions of tarsal glands.
 Tarsus is a fibrous plate that is embedded with Meibomian
glands.

4. Function
a) Protect the eye from entrance of foreign
particles.
b) Aid in removing foreign particles by blinking.
c) Distribute tear film and aid in propulsion of tears
toward the lacrimal puncta.
d) Removal of visual stimuli for sleeping.
e) Contains glands that contribute to the tearfilm.

5.  Ankyloblepharon:
Delayed OR Premature
Opening of the eyelids
in neonates.
 It results in corneal
desiccation, keratitis,
corneal ulceration, and
conjunctivitis.
 Treatment
 consists of frequent
application of a topical
lubricating ophthalmic
ointment.

6.  Eyelid coloboma refers to
congenital absence of a
portion of an eyelid. It is
most common in cat.
 Eyelid colobomas are
repaired with a variety of
blepharoplastic
procedures; the choice
depends on the size and
position of the defect.

7. The three common disorders are,
1. Distichiasis: Cilia emerge from
the openings of the meibomian
glands.
2. Ectopic cilia: Cilia arise from
the meibomian glands and
emerge through the palpebral
conjunctiva. Ectopic cilia are
common on the upper eyelid.
3. Trichiasis: Cilia arising from a
normal location are
misdirected so that they touch
the cornea.
Distichiasis:

8.  Inward rolling of the eyelid
margin
 Conformational entropion
occurs most frequently in dogs
and sheep. It usually affects
both eyes.
 Spastic entropion occurs with
spasm of the orbicularis oculi
muscle (blepharospasm) due
to painful ocular conditions
such as ulcerative keratitis, or
conjunctivitis.
 Treatment: Wedge Resection

9.  Eversion of the eyelid
 Invariably affects the lower eyelid only.
 The most common type is conformational.
Treatment:
Wedge resection.

10.  It is usually a sign rather
than a disease.
 Caused due to immune
mediated process like
angioedema, insect
bite/stings, vaccines etc.,
and also by trauma.
Therapy: steroids,
antihistamines.

11.  Forms:
 Hordeolum is an acute
abcessation of one or more
meibomian glands of eyelid.
 Chalazion is a chronic lipid
granuloma, caused from
meibomian gland contents
being liberated into adjacent
tissue after blockage of gland.
 Pyogranuloma & furunculosis
are deep infections of hair
follicles.
Hordeolum
Chalazion
Pyogranuloma

12.  Dog: meibomian adenoma,
papilloma, histiocytoma,
melanoma
 Cat: squamous cell
carcinoma.
 Horse: squamous cell
carcinoma, equine sarcoid,
melanoma.
 Cattle: squamous cell
carcinoma
Meibomian adenoma
Equine sarcoid
Squamous cell carcinoma