Sclera/Cornea Flashcards
(175 cards)
What is the anterior and posterior portion of the fibrous tunic
Anterior: Cornea
Posterior: Sclera
What are the different layers of the sclera
1) Episclera- vessels and nerves
2) Sclera proper- dense fibrous
3) Lamina fusca- inner elastic layer
What is the inner most elastic layer of the sclera
Lamina fusca
What layer of the sclera contains vessels and nerves
cannot be moved
episclera
What is the dense, fibrous later of the sclera
sclera proper
junctional zone between sclera and cornea
limbus
Collagen arrangement in the sclera is ______ while the cornea is _______
Sclera: random
Cornea: ordered
opening in the sclera for the optic nerve
lamina cribrosa
why might the cat and horse be more resistant to optic nerve damage with glaucoma
cats have elastic lamina cribrosa
dogs have a rigid lamina cribrosa which means as globe stretches, ganglion cells get compresses
congenital malformation of the eye causing a defect in the lens, iris, retina, sclera, optic disk
usually optic disk
Coloboma
coloboma is most common in what breeds
Collies- Collie eye syndrome (anomaly) CEA
Australian Shepherds- multiple ocular anomaly (MODS)
multiple ocular anomaly (MODS)
coloboma present in Australian shephards
congenital malformation of the eye causing a defect in the lens, iris, retina, sclera, optic disk
usually optic disk
Collie eye anomaly (CEA)
coloboma present in collies
congenital malformation of the eye causing a defect in the lens, iris, retina, sclera, optic disk
usually optic disk
Coloboma
congenital malformation of the eye causing a defect in the lens, iris, retina, sclera, optic disk
usually optic disk
-Collies and Australian Shephards
ex:
1) Microphthalmia
2) Iris colobomas
3) Optic nerve coloboma
What are different scleral diseases
1) Inflammatory- episcleritis/scleritis
2) Neoplasia- usually arises at limbus
3) Trauma
neoplasia of the sclera typically arises at the
limbus
You take a scleral biopsy to see if the causes is inflammatory or neoplastic, what confirms that it is inflammatory
granulomatous inflammation
What are the 3 types of scleral inflammation
1) Diffuse episcleritis
2) Nodular scleritis
3) Nodular granulomatous episclerokeratitis (NGE)
all look very similar
How does diffuse episcleritis typically present *
“red eye”
rule out other causes of “red eye” (conjunctivitis, uveitis, glaucoma)
What are the clinical signs of diffuse episcleritis *
1) Diffuse episcleral injection (red eye) *
2) Little to no pain or ocular discharge
3) Usually no intraocular abnormalities
4) Peri-limbal corneal edema *
5) Normal or low intraocular pressure
What causes “red eye”
1) Episcleritis
2) Conjunctivitis
3) Uveitis
4) Glaucoma
What commonly causes episcleritis
think its immune mediated inflammation
-present in certain breeds
sub-conjunctival scleral swelling near limbus
adjacent peri-limbal edema
generally painful
nodular scleritis
T/F: episcleritis is typically painful
False