Feline Opthamology

Question 1

• Coloboma

Answer 1

– Absence of palpebral margin
– Concurrent intraocular anomalies – Congenital, genetic
– Surgical correction • Rotational flap
• Cryotherapy

Question 2

Eyelids: Blepharitis

Ophthalmia neonatorum

Answer 2

– FHV-I ?
– Bulging eyelids prior to opening • Mucopurulent discharge
– Open eyelids
• Irrigate conjunctiva • Topical antiobiotic • Topical lubrication

Question 3

Eyelids: Blepharitis - parasites

Answer 3

• Parasites
– Demodex, Ntoedres cati – Skin scrapings
– Consult dermatologist • Ivermectin (off label)
• Lime sulfur dips

Question 4

Conjunctivitis - causes

Answer 4

Feline herpes virus type 1**** most common
Chlamydophila
Mycoplasma

Question 5

Conjunctivitis - diagnosis/treatment

Answer 5

• Diagnosis: culture, cytology, PCR
• Treatment
– Topical tetracycline
     • Chlamydophila, Mycoplasma
– Systemic tetracycline 
     • Chlamydophila

Question 6

Cornea: FHV - 1

Answer 6

Dendritic ulcers/geographic ulcers
Latency
Diagnosis: Cytology/initial exam; IFA; PCR

Question 7

Cornea: FHV-I - treatment

Answer 7

1. Topical Antibiotics
– Tetracycline, chloramphenicol, tobramycin
2. Antivirals
– Topical: trifluridine 
– Oral: famciclovir
3. Lysine
4. Interferon?
5. Corneal lubrication

Question 8

Describe stromal keratitis caused by FHV-1

Answer 8

• Stromal keratitis
– FHV deep within stroma
– Clinical signs more severe
– Longer treatment

Question 9

Corneal sequestrum

Answer 9

If it’s domestics it is likely due to FHV whereas if it is purebred it is likely genetic.
(18-55% FHV-I + by PCR)
– Sequel of prolonged corneal irritation
Can treat medically or surgically (avoid rupture, repeat & infection)

Question 10

Eosinophilic Keratitis

Answer 10

It is eosinophilic infiltrates that will pass across the cornea and lead to blindness if left unchecked.
This can be caused by FHV-1.
Cytology - will see WBC (eosinophils) which is not normal. You should not see WBC on this.
Therapy:
– Treat like FHV-I
– Put on Topical corticosteroids (Put this on after 2 weeks, 1 or 2 times a day unless they are going blind - will regress)

Question 11

Bullous keratopathy

Answer 11

Quite rare, cornea bulges forward (vesicle of edema) due to severe corneal edema.
The cause is unknown & it is Fluorescein negative.
Treatment: graft or put a third eyelid flap on. You can use hypertonic saline, but usually this doesn’t work.

Question 12

Uveitis - Causes

Answer 12

Infectious (FeLV, FIP, FIV)
Neoplastic (lymphoma)
Lens induced (less prevalent in the cat than the dog)

Question 13

Uveitis - clinical signs

Answer 13

Pain
Aqueous flare
Iritis
Retinal lesions
Diagnosis - refer to causes

Question 14

Uveitis - treatment

Answer 14

• Treatment
– Corticosteroids • Topical
• Systemic
• Subconjunctiva

Question 15

Glaucoma

Answer 15

• Secondary to uveitis
• High intraocular pressures
• Therapy
– Mannitol
– Beta blockers – CAI
– Corticosteroids – Enucleation

Question 16

Normal cat fundus

Answer 16

Optic disk is very small, blood vessels come to the edge of the disk and disaapear (non-vascular ring). There is a tapetum & non-tapetum for most of them

Question 17

Nutritional Retinal Degeneration

Answer 17

 Taurine deficiency
 Granular tapetum
 Hyper reflective lesion
 Loss of retinal vasculature
 Supplementation - needed especially for Home made diets

Question 18

Retinal dysplasia/degeneration

Answer 18

Rod-cone dysplasia/degeneration 
Common in Abyssinian
causes blindness
 4 weeks: dysplasia
      Similar to dogs
 2 yrs: degeneration
      Similar to PRA

Question 19

Hypertensive retinopathy

Answer 19

Older cats (cat has peeing, losing weight, sleeping - hypertensive)
Due to systemic hypertension
Causes retinal detachment, hemorrhages
Can diagnose based on physical exam, BP
Amlopidine - consult internal medicine.
Usually bilateral. may see retinal edema at first. Usually above 200 mmHg when bilateral.

Question 20

Baytril toxicity

Answer 20

Anything over >5mg/kg/day (7 for 4 days - blind for life)
Causes acute blindness and retinal atrophy
This is off label use. You can use it at 2.5 mg/kg/day but must be at the label dose

Question 21

Squamous cell carcinoma in cats

Answer 21

Squamous cell carcinoma - very invasive, need to get it very early and take very wide margins. Around the eye you don’t have a lot of tissue to work with. Need radiation/cryotherapy as well. (erosive plaques or nodules)

Question 22

Diffuse iris melanoma

How to see, how to treat

Answer 22

Pigment spots in both eyes - watch over time & take pictures
Do a FNA/biopsy of iris
Diode laser/enucleation.
If it’s in the iris - then you are ok, but if left to long, then not as good.

Question 23

Traumatic intraocular sarcoma

Answer 23

Malignant intraocular mass
Takes years to arise (cat claw in eye)
It is associated with the lens capsule rupture
Treatment is enucleation.
Usually has weeks to months to live.