Rates of visual field progression before and after trabeculectomy

Abstract

AbstractPurpose To compare the rates of change in the visual field (VF) in patients with glaucoma before and after trabeculectomy.Methods 52 eyes of 52 patients over 35 years of age with different types of chronic glaucoma who underwent primary trabeculectomy were evaluated retrospectively. Pre‐ and postoperative automated visual fields measured by the same technique were compared to detect differences in rates of progression. Rates of VF loss before and after trabeculectomy were calculated using global indices, mean defect (MD) and pattern standard deviation (PSD) and linear regression analysis per cluster. Linear mixed models were used to compare the evolution of the VF before and after trabeculectomy.Results The mean follow‐up period pre‐trabeculectomy was 3.88 years (min 0.92, max 10.72) and post‐trabeculectomy 3.82 years (min 2.03, max 8.02). The intraocular pressure (IOP) decreased significantly from 18.12 ± 4.71 mmHg before trabeculectomy to 11 ± 2.87 mmHg at the last follow‐up after trabeculectomy (P < 0.0001). The rate of progression of MD decreased with 55%, from –0.36 dB/year before surgery to –0.16 dB/year after surgery (P = 0.15). The rates of progression of PSD decreased from –1.69 dB/year before to –0.018 dB/year after surgery (P = 0.03). Of the 10 predefined clusters, only in cluster 10, situated infero‐temporally, the difference between the slopes was statistically significant (0.64 dB/year, P = 0.0021).Conclusion Trabeculectomy significantly decreased the rates of glaucomatous VF progression.