Clinical signs in ophthalmology

Question 1

Most eye diseases are in what area of the eye?

Answer 1

the “front”: conjunctiva, cornea, anterior chamber

Question 2

FIP and ocular signs

Answer 2

The signs of feline infectious peritonitis vary depending on which organs are involved. Many organs, including the liver, kidneys, pancreas, CNS, and eyes, can be affected.

The initial clinical manifestation is unilateral or bilateral anterior uveitis manifested by change in iris color, cloudiness, and flocculant debris in the anterior chamber, keratic precipitates on the back side of the cornea, and anisocoria.

Question 3

What disease causes pink eye in cattle?

Answer 3

keratoconjuntivitis, bo rhinotracheitis caused by bovine herpes virus

Question 4

Equine pupil shape?

Answer 4

horizontal oval

Question 5

Squinting/holding the eye shut/blinking excessively is called…?
Its due to…?

Answer 5

blepharospasm

Acute pain, irritation (inflammation)

Question 6

How would you describe these eyes?

Answer 6

Red, irritated eyes so conjunctival hyperemia; severe edema/swelling is chemosis. Erythema can affect the eyelids.
* Causes: irritation, inflammation

Chemosis is the swelling (or edema) of the conjunctiva.

Question 7

When horses “pull their eyes into the orbita” it is…

Answer 7

the equine version of blepharospasm.

Cats and dogs don’t pull their eyes back and in, but horses do.

Question 8

Grey, brown, green/yellow ocular discharge can indicate

Answer 8

Inflammation, irritation

Question 9

Answer 9

lacrimation, runny eyes aka epiphora

Question 10

The causes of epiphora can be divided into groups: (4)

Answer 10

• Increased tear production e.g. reflex lacrimation indicating inflammation, mechanical irritation of eye (e.g. entropion, distichiasis etc.).
• Tear drainage disorder
• Anatomical imperfection of tear drainage pathways
• A combination of several factors can be present.

Question 11

3 things a cloudy, grey cornea can be

Not diseases.

Answer 11

corneal edema
corneal scar
corneal dystrophy (benign)

Question 12

Answer 12

corneal edema

Question 13

Answer 13

corneal scar

Question 14

Answer 14

Benign corneal dystrophy
– accumulation of calcium/cholesterol crystals in the corneal stroma (middle layer).

Can be due to genetic predisposition in certain breeds.

Question 15

Answer 15

Cloudiness of the pupil area which can indicate cataracts.

Cataracts must be distinguished from normal age-related lens sclerosis aka nuclear sclerosis.

Question 16

How to tell corneal edema from cataracts/sclerosis?

Answer 16

In cataracts/sclerosis, you can always see the border of the iris/pupil.

If its obscured then its more likely corneal edema.

Looking at the eye from various angles will help you too.

Top is cataract, bottom is corneal edema, note that the iris/pupillary margin is properly visible.

Question 17

How to tell cataracts from nuclear sclerosis?

Answer 17

Ophthalmoscopy helps:
* In case of nuclear sclerosis (1), nothing interferes with observing the fundus, there are no spots on the lens.

• In case of cataract (2) – the fundus is not well visible, there are opaque areas in the lens.

Question 18

If the lacrimal gland doesn’t produce sufficient tears…

Answer 18

the conjunctiva will try to compensate by producing too much mucus.

E.g. in KCS

Question 19

Brown/black spots on the cornea can indicate? (3)

Answer 19

Most common in dogs, rare in horses and cats.

• Corneal pigmentation, melanoSIS of the cornea (NOT the same as melanoMA)
• Chronic irritation
• Chronic inflammation

In cats, it can be corneal sequestrum/necrosis.

Question 20

Define limbus.

Answer 20

The limbus forms the border between the transparent cornea and opaque sclera, contains the pathways of aqueous humour outflow, and is the site of surgical incisions for cataract and glaucoma.

Melanocytes can migrate from limbus to near by sclera due to chronic inflammation (see pictures, brown pigment on sclera).

Question 21

Causes of feline corneal sequestrum/necrosis. (4)

Answer 21

• Corneal irritation, usually chronic (like entropion)
• Feline Herpes Virus infection
• Iatrogenic drying of the cornea during general anesthesia
• Idiopathic

Often Persian and British short haired cats.
Often bilat, but at different times.

Question 22

Which chamber has aqueous humor and which, virteous?

Answer 22

Anterior - aqueous
Posterior - vitreous

Question 23

Answer 23

Cornea is cloudy + red = edema +
vascularisation and granulation

• Irritation
• Inflammation
• Part of healing process

Question 24

What’s this and what can cause it? (8)

Answer 24

Protrusion of third eyelid.

Can be due to:
* Pain/light hypersensitivity
* Irritation, 1
* Inflammation, 1

• Third eyelid lacrimal gland prolapse (cherry eye) or eyelid eversion, 2
• Neurological problem (like Horner’s syndrome), 3
• Small eye (congenital), big orbita and large eyelid
  fissure (macroblepharon), 4
• Neoplasia
• Idiopathic, Haw’s syndrome in cats (both protrude)

Question 25

What is Haw's syndrome?

Answer 25

Haw's syndrome is a relatively common problem in cats. It is a condition where both third eyelids protrude (or prolapse). Protrusion of the third eyelids can occur for many reasons in cats. When it has a sudden onset, and is associated with diarrhea or other gut conditions, it is called Haw's syndrome. Usually occurs in cats around a year old but older cats can also be affected.

Question 26

3 main differentials for iris changes/spots

Answer 26

inflammation/uveitis neoplasia (iris melanoma) normal iris pigmentation (nevus)

Question 27

Answer 27

Neoplasia – malignant diffuse iris melanoma

Question 28

Answer 28

Neoplasia –malignant focal iris melanoma

Question 29

Answer 29

Normal iris pigmentation (nevus,freckle)

Question 30

Answer 30

inflammation/uveitis

Question 31

Bleeding/hemorrhage in anterior chamber is called? Can be due to? (6)

Answer 31

hyphema - trauma - systemic hypertension - blood clotting problem - paraneoplastic syndrome - uveitis - glaucoma

Question 32

Answer 32

Persistent pupillary membranes.

Question 33

The one eye bigger than the other can indicate... (3)

Answer 33

* High intraocular presssure (glaucoma) * Neoplasia * +/-inflammation

Question 34

Diagnosing eye problems should include: (6)

Answer 34

1. Describe changes (swelling, what color spots, blood vessels, hyphema, blepharospasm etc.) 2. Localize where exactly the changes are (conjunctiva, cornea, iris, etc.) 3. What the changes mean (inflammation, irritation, pain etc.) 4. Diagnosis at eye level (conjunctivitis, keratitis, corneal ulcer, uveitis, etc.) 5. Think about animal species! 6. Diagnosis at the causal level (viral conjunctivitis due to systemic herpesvirus, corneal ulcer due to foreign body or trauma, uveitis due to infectious feline peritonitis etc.)

Question 35

define corneal and iris melanosis

Answer 35

Abnormal accumulation of pigmented (i.e. often brown) cells in the eye and can eventually block the drains that are responsible for removing fluid from the eye. Ocular Melanosis is inherited.

Question 36

inflammatory cells in the anterior chamber of the eye is termed...

Answer 36

hypopyon

Question 37

vascular layer of the eye

Answer 37

uvea

Question 38

uvea may be divded into (3)

Answer 38

iris, ciliary body, choroid

Question 39

aqueous humor is produced in

Answer 39

the ciliary body (posterior chamber)

Question 40

drainage of aqueous is through the

Answer 40

iridocorneal angle ## Footnote The outer opening of the iridocorneal angle is spanned with the pectinate ligament. Disturbed development of the ligament may narrow the angle, predisposing for glaucoma..

Question 41

What keeps the lens in its proper position

Answer 41

The zonula-zinni fibres extend from the ciliary body to the lens and keep the lens in its proper position. The fibres are able to retract and relax, thus altering the shape of the lens (accommodation). A severe blunt trauma against the eye, or in glaucoma with enlargement of the globe may cause the fibres to rupture, resulting in displacement (subluxation or luxation) of the lens. A primary defect in the fibres may also be present; this condition is inherited in some dog breeds (the terrier breeds, Tibetan terrier and border collie). (Primary Lens Luxation (PLL).)

Question 42

Contraction and relaxation of the pupil are dependent on?

Answer 42

the M.sphincter pupillae which is innervated by the III cranial nerve (N.oculomotorius) and M.dilator pupillae innervated by the sympathetic nerve.

Question 43

The retinal pigment epithelium (RPE) is the outer layer of the retina. The RPE cells lack pigment in the tapetal area. Animals with an albinotic fundus (back of the eye), for instance blue merle-colored dogs, often lack pigment in the whole RPE. The RPE may also be poorly pigmented in color-diluted dogs, making the choroid vessels visible. The RPE is necessary for

Answer 43

normal photoreceptor function. Vitamin A is stored here.

Question 44

eye disease PRA

Answer 44

In the disease Progressive Retinal Atrophy (PRA) the rods initially undergo degeneration. Reduced vision in dim light together with diminished side vision (tunnel vision) is therefore the initial clinical signs of the disease. Rods are mostly situated in the periphery of the retina. most common in middle aged to older dogs.

Question 45

FIP can cause what eye disease? severe otitis can affect the eyes, how? what can lymphoma do to the eyes?

Answer 45

uveitis can cause Horner's also uveitis