Cornea

Question 1

Facet

Answer 1

Loss of corneal stroma with intact overlying epithelium. This occurs because epithelialization progresses more rapidly than stromal healing.

Question 2

Cornea edema

Answer 2

The only ‘blue’ opacity. Corneal edema often appears heterogenousor fluffy. There are only two common sources of corneal edema:

Epithelial disruption –think corneal ulceration

Endothelial disruption–think uveitis, glaucoma, or less commonly degeneration/dystrophy

Question 3

Superficial corneal neovascularization

Answer 3

This vessel pattern occurs in response to superficial disease processes. Think of KCS, eyelid disorders, feline herpesvirus, and superficial corneal ulcers etc. These vessels are tree-like in their appearance, can often be seen crossing the limbus, and can coalesce to form raised granulation tissue

Question 4

Deep corneal neovascularization

Answer 4

This vessel patter occurs in response to deep disease processes. Think of deep/infected corneal ulcers and uveitis. These vessels are usually straight, cannot be seen crossing the limbus and do not extend as far across the cornea as superficial vessels

Question 5

Ciliary flush (Ciliary neovascularization)

Answer 5

360 degree deep corneal neovascularization that is pathognomonic for uveitis. ‘Ciliary’ refers to the ciliary body, implying that these vessels arrive in the cornea from an intraocular, or, deep, origin

Question 6

White blood cell corneal infiltration

Answer 6

This falls within our ‘white’ category of corneal opacity and is a sign of active inflammation (keratitis). White blood cell infiltration is often painful and signals infection. Presence typically signifies an ocular emergency. These infiltrates can have a yellow or green appearance and are most commonly observed in equine stromal abscesses and cases of corneal melting “keratomalacia”

Question 7

Corneal fibrosis

Answer 7

AKA corneal scarring. This results from stromal collagen contracture and appears as a dull, wispy white. You might see ghost vessels present from past active keratitis. This is non-painful

Question 8

Corneal dystrophy or degeneration

Answer 8

Dystrophy most often involves corneal lipid and appears glittery/shiny. Degeneration most often involves calcium and appears gritty, or chalky.

Question 9

Feline corneal sequestrum

Answer 9

We don’t know what causes the brown or black discoloration! This condition results from chronic corneal irritation and/or ulceration. The most common cause of corneal ulceration is feline herpesvirus

Question 10

Keratic precipitates

Answer 10

These are cellular adhesions to the endothelium and are pathognomicfor uveitis. They have a classic appearance that can be easily recognized. You will see tiny dots from the mid-portion of the cornea that become larger and denser in the ventral cornea.

Question 11

Superficial corneal ulceration

Answer 11

loss of the corneal epithelium without any loss of corneal stroma

Question 12

Simple, or, Uncomplicated Corneal ulcer

Answer 12

A superficial corneal ulcer that heals according to the expected time frame (< 7 days)

Question 13

Complex, or, Complicated Corneal ulcer

Answer 13

Any ulcer that does not heal within the expected time frame (> 7 days).

Question 14

ndolent ulceration, or Spontaneous Chronic Corneal Epithelial Defect (SCCED), or Boxer Ulcer

Answer 14

A canine-specific form of complex corneal ulceration in which the epithelium fails to adhere to the stroma

Question 15

Reflex uveitis

Answer 15

The trigeminal nerve and certain cytokines cause direct stimulation of the ciliary body, inducing spasm, pain, and disruption of the blood ocular barrier (i.e. uveitis)

Question 16

Descemetocele

Answer 16

A corneal ulcer that has reached the depth of Descemet’s membrane. This has a classic staining pattern that you should be familiar with.

Question 17

Keratomalacia

Answer 17

softening of the cornea due to collagenolysis from infection and the ocular inflammatory response. Often used when describing “Melting Corneal Ulceration”

Question 18

Collagenolysis

Answer 18

Enzymatic destruction of the corneal stroma that signals infection. Bacteria, most often Pseudomonastrigger collagenolysis. The body’s ocular inflammatory response from white blood cells (neutrophils) also causes similar destruction Often used when describing “Melting Corneal Ulceration”

Question 19

Iris prolapse

Answer 19

one of the only rule outs for a brown, raised, corneal opacity. The iris will rush forward to plug a corneal perforation in certain circumstances.

Question 20

Sequestrum

Answer 20

a devitalized portion of feline corneal stroma that pigments amber to black. The cause for the pigment is unknown, though this condition often forms following chronic or recurrent corneal ulceration.

Question 21

Pannus, or, Chronic Superficial Keratitis

Answer 21

An autoimmune condition that is inherited in German Shepherds and Greyhounds. This condition forms progressive pigment and granulation tissue across corneal and conjunctival epithelium. It is painless, though blinding if left untreated. Ultraviolet let is thought to exacerbate this problem.

Question 22

Pigmentary Keratitis

Answer 22

Most commonly seen in the Pug. This a condition that involves superficial corneal pigment migration from the limbus. Its presence suggests that superficial inflammation is present.