Comparison of visual outcomes between medical treatment alone and Ahmed glaucoma valve implantation in Shiba dogs with primary angle closure glaucoma.

Abstract

The objective of the study was to evaluate visual outcomes between medical treatment alone (MED) and Ahmed glaucoma valve implantation (AGVI) in Shiba dogs with primary angle closure glaucoma (PACG). Records of 65 Shiba dogs (104 eyes) with PACG were retrospectively reviewed. Vision was assessed qualitatively using both the menace response and maze testing. The significance of age, sex, intraocular pressure (IOP), and duration of clinical signs (≤72 h or >72 h) at first presentation (V1) was assessed. Eyes with vision at V1 were divided into groups according to subsequent treatment method (MED versus AGVI), and vision as a survival outcome was compared between group by the Kaplan-Meier method. At V1, 65 eyes (62.5%) of 54 dogs had vision. There was no statistically significant difference in age or sex on the presence of vision at V1. Median IOP was higher in blind (52 mmHg) compared to sighted eyes (28 mmHg) (p < .001). Eyes presenting in ≤72 h of the onset of clinical signs were more likely to have vision (86.7%) compared to those presenting after 72 h (44.1%) (p < .001). By the Kaplan-Meier analysis, the cumulative visual retention rate was significantly higher with AGVI than with MED (69.2% vs. 7.7%; p < .01) at 12 months. The median time to visual loss was 39.9 months with AGVI vs. 1.7 months with MED. AGVI resulted in better visual outcomes than MED and should be considered in Shiba dogs with PACG that are visual at the time of presentation and suitable for surgery.