Effects of ocular administration of ophthalmic 2% dorzolamide hydrochloride solution on aqueous humor flow rate and intraocular pressure in clinically normal cats.

OBJECTIVE

To determine the effects of ocular administration of ophthalmic 2% dorzolamide hydrochloride solution on aqueous humor flow rate (AHFR) and intraocular pressure (IOP) in clinically normal cats.

ANIMALS

20 clinically normal domestic shorthair cats.

PROCEDURES

Following an acclimation period, IOP was measured in each eye of all cats 5 times daily for 3 days to determine baseline values. Fifteen cats received 1 drop of 2% dorzolamide solution and 5 cats received 1 drop of control solution in each eye every 8 hours for 5 days (treatment phase). The IOP of each eye was measured 5 times during each day of the treatment phase. Prior to and after the treatment phase, AHFR in both eyes of each cat was measured via fluorophotometry.

RESULTS

Prior to treatment, AHFR or IOP did not differ between the treatment and control groups. In dorzolamide-treated cats, mean AHFR after the treatment phase (3.47 ± 1.5 μL/min) was significantly lower than the value prior to treatment (5.90 ± 2.2 μL/min) and mean IOP during the treatment phase (11.1 ± 1.0 mm Hg) was significantly lower than the baseline mean IOP (14.9 ± 1.0 mm Hg). In the control group, IOP values did not differ before or during the treatment phase and AHFRs did not differ before and after the treatment phase.

CONCLUSIONS AND CLINICAL RELEVANCE

Ocular administration of 2% dorzolamide solution significantly decreased AHFR and IOP in clinically normal cats. Application of 2% dorzolamide solution may be an effective treatment in cats with glaucoma.