Ophthalmic examination of the cat is different to other species, even dogs. Initially the cat is observed from a distance in order to assess the nature and severity of the ocular problem.
TEST If appropriate, the cat should be allowed to move freely about the consulting room; this provides a very crude method of assessing vision.
For a detailed examination of the lens, vitreous and fundus, instillation of a mydriatic is essential. This is because, in comparison to the dog, the pupil of normal cats responds briskly and more completely to bright light and the pupil shape changes from round to a narrow vertical slit, resulting in a very limited field of view. Tropicamide 1% is the drug of choice.
A thorough examination of the eye includes examination of the eyelids, cornea (including fluorescein staining; schirmer tear test and tonometry), iris, lens, vitreous and fundus.
Examination of periorbital structures is used to check for any facial swellings associated with periorbital abscesses, fractures, or neoplasia. An examination of the mouth is conducted to examine for draining abscesses or protruding tumours.
- Neuro-ophthalmology examination
- Congenital eye diseases
- Diseases of the retina
- Diseases of the lens
- Diseases of the iris
- Diseases of the cornea
- Diseases of the eyelids
Common eye diseases
The owners noticed an increasing red mass behind the iris during the 4 months prior to the examination. The tumor originated from the ciliary body epithelium and extended posteriorly, detaching the retina.
Angioinvasive metastatic squamous cell carcinoma (13 year old DSH). This fundus photograph of that eye shows abnormal pigmentation and gray infiltrates beneath a retinal detachment, marked by the arrows. Tumor cells extended with luminal blood vessels deeply into the choroid and retina.
Chlamydophila spp infection in an 8 mth old DSH
Persistent pupillary membrane (4 month old Himalayan)
Hypertrophic glands nictitans (6 year old Burmese)
Primary glaucoma (7 y.o DSH). The IOP in the right eye was 26 mm Hg and the left was 23 mm Hg. Both pupils had a sluggish PLR. This photograph is a lateral view of the left eye showing an anterior displaced iris and lens. The normally deep anterior chamber is extremely shallow and exists between the two arrows.
Lens resorption in a 4.5 y.o. DSH. This cat was first examined at 12 weeks of age. At that time, the kitten was blind from bilateral mature cataracts. With the passage of time, the lenses have reduced in diameter. With the pupil dilated, the normal tapetal reflex can be seen 360°. The ciliary processes are present (arrows) attached directly to the wrinkled lens capsule. When dilated, the cat had functional vision.
Meibomian gland inflammation. This close-up photograph is representative of all four-lid margins. The black discharge adheres tightly to the periocular area. Caseous plugs (arrow) are present at each meibomian gland opening. The conjunctival was chemotic and hyperemic. All cultures were negative.
Optic neuritis in a 10 y.o. DSH. This cat was presented with a unilateral anterior uveitis with focal swelling of the iris. The photograph of the same eye shows a loss of detail of the optic disc due to severe cellular infiltrates (black arrows). The entire retina, especially around the optic disc, is edematous and detached. Intraretinal hemorrhage is also present. Feline leukemia virus was positive on serology. Histopathology on the globe demonstrated lymphosarcoma of the choroid, ciliary body and iris.
Retinitis secondary to hypertension. This cat was presented due to hyphaema in the opposite eye. This photograph is typical of early hypertensive retinopathy. Multiple areas of retinal edema are present. A large bullous detachment is present superior (arrow). The systolic blood pressure was 260 mm Hg.
Scleral shelf melanoma in a 11.5 y.o. DLH
Ocular manifestations of systemic disease
|Causes||Prevalence||Blepharitis||Conjunctivitis||Keratitis||Ant Uveitis||Lens||Chorioretinitis||Central blindness|
|Nervous system diseases|