Is it necessary to wait several minutes between applications of different topical ophthalmic solutions? A preliminary study with tropicamide eye drops in healthy dogs.
Vet Ophthalmol 2021;
24:374-379. [PMID:
34402570 DOI:
10.1111/vop.12905]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/25/2021] [Accepted: 05/07/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE
To evaluate the efficacy of topical tropicamide when placed at different time intervals before or after a saline drop.
ANIMALS STUDIED
Eight healthy Labrador and golden retriever dogs.
PROCEDURES
The effect of 1% tropicamide on pupillary diameter (PD) was measured over 240 min when administered alone (control) and then 1 and 5 min prior to, or following, application of a saline drop, with 1-week washout between each of the five trials. Data were analyzed using repeated-measures ANOVA and Tukey post hoc test.
RESULTS
Only 6/110 pairwise comparisons among the 5 trials were statistically significant (p ≤ .035), with post-hoc analysis showing no significant differences (p ≥ .14) between the overall means of all trials. In all five trials, maximal PD was reached 30 min after tropicamide application and maintained until 210 min for 180 min (p = .0005).
CONCLUSIONS
Our results suggest that waiting 1 min between applications of different ophthalmic solutions may be sufficient for maximal drug effect. Care should be taken when extrapolating these results to other species and different ophthalmic formulations.
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