Visual outcome following phacoemulsification in English Cocker Spaniels with suspected progressive retinal atrophy: A retrospective multicenter study of 54 cases (2002‐2017)

Abstract

Objective To describe the visual outcome following phacoemulsification in English Cocker Spaniels (ECS) affected by cataracts and suspected progressive retinal atrophy (PRA). Animals studied Fifty‐four client‐owned dogs. Procedures A multicenter, retrospective study was performed including ECS with suspected PRA which underwent phacoemulsification. PRA was suspected on ophthalmic examination before and after surgery, and/or after electroretinography (ERG) was performed. Visual outcome was assessed by menace response per eye at seven time periods post‐surgery (P1= 25‐90 days, P2 = 91‐180 days, P3 = 181‐364 days, P4 = 365‐549 days, P5 = 550‐729 days, P6 = 730‐1094 days, and P7 ≥ 1095 days). Descriptive statistics were performed. Generalized estimating equations were used to identify predictors associated with vision after surgery. Odds ratio and confidence intervals were reported. Significance was set at P < 0.05. Owners were invited to participate in a questionnaire. Results Phacoemulsification was performed in 85 eyes. Median age at surgery was 9.09 years (min. 2.17 years, max. 13.49 years). At all re‐examinations, up to and including P5, significantly more eyes were visual than before surgery (P ≤ 0.003). Odds for vision were significantly increased for eyes that underwent surgery. Electroretinograms were performed in 75/85 eyes that underwent surgery, demonstrating low b‐wave amplitudes. There was no significant effect of the age, gender, vision before surgery, presence of dazzle reflex, cataract stage or abnormality on gonioscopy on visual outcome. The questionnaire response rate was 48.2%. Most participants (92.5%) felt that cataract surgery led to improvement of the dog's quality of life. Conclusions English Cocker Spaniels with suspected PRA may benefit from phacoemulsification with vision up to 2 years following surgery.

Clinical usefulness of transient visual evoked potentials (TVEPs) and steady-state visual evoked potentials (SSVEPs) results in blind dogs

“…Therefore, ERG is severely reduced when only part of the retinal function remains due to retinal degeneration, but VEPs are detectable. In a study by Koll-Hampp et al, although ERG was undetectable, English Cocker Spaniels with suspected PRA showed signi cant visual improvement after phacoemulsi cation [34]. VEPs were not assessed in their study; however, there may have been an association between VEPs and visual improvement after phacoemulsi cation in patients with cataracts with undetectable ERG.…”

Association between preoperative gonioscopic status and postoperative glaucoma after phacoemulsification in dogs: A retrospective cohort study of 505 eyes

“…A high prevalence of goniodysgenesis was found in eyes from Cocker Spaniels that were removed due to glaucoma after surgery, but the prevalence of goniodysgenesis in eyes that did not develop glaucoma, and in eyes that developed glaucoma but were not enucleated, was not assessed. In a study of phacoemulsification in English Cocker spaniels with progressive retinal atrophy by Koll‐Hampp et al, 21 demonstrated that of 16 dogs with gonioscopic abnormalities prior to phacoemulsification, none developed glaucoma after surgery, however, follow‐up times for these 16 dogs were not reported. In a case‐control study, Lannek and Miller observed 70% of dogs in the postoperative glaucoma group had narrow or closed ICAs compared with 52% in the postoperative nonglaucoma group but the P ‐value for this association was high 8 .…”

“…Several studies have assessed whether preoperative abnormal gonioscopy findings are risk factors for postoperative glaucoma after phacoemulsification 8,21‐23 with varied results. The objective of this study was to assess whether gonioscopy status prior to cataract surgery is associated with development of postoperative glaucoma in dogs.…”