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OBJECTIVE: To determine intraocular pressure (IOP) in cats ≥ seven years of age undergoing a routine comprehensive geriatric health examination. DESIGN: Prospective study. ANIMALS: Five hundred and thirty-eight cats (1068 eyes). PROCEDURE: IOP was measured by applanation tonometry following instillation of 0.5% proparacaine. RESULTS: Mean ± SD IOP for all eyes was 12.3 ± 4.0 mmHg (range, 4-31 mmHg). Mean age was 12.3 ± 2.9 years. Intraocular pressure did not vary significantly cross-sectionally with age. However, in 78 cats, IOP was measured more than once, and follow-up measurements were significantly less than initial measurements (mean time between measurements, 9.4 ± 3.0 months). The most useful tonometric criteria for identifying ocular abnormalities on the basis of IOP was an IOP ≥ 25 mmHg (mean + 3 SD) or a difference in IOP between eyes ≥ 12 mmHg. Eight cats met these criteria, and five of these cats had ophthalmic abnormalities. Low IOP was a nonspecific indicator of the presence of ocular abnormalities, as 111 cats had an IOP ≥ 8 mmHg, but only two had uveitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that IOP measurements can be a useful addition to a comprehensive geriatric health examination in cats ≥ seven years of age, especially when combined with an ophthalmic examination. Cats without ocular abnormalities that have IOP ≥ 25 mmHg or a ≥ 12 mmHg difference in IOP between eyes should have tonometry repeated or be referred to an ophthalmologist for further evaluation before beginning antiglaucoma treatment.
Dr. M.M. Kroll, Cat Care Clinic, Madison, WI 53705, USA
5 Experimental glaucoma; animal models
1.6 Prevention and screening (Part of: 1 General aspects)