Localised changes in glaucomatous visual fields after trabeculectomy.

Abstract

BACKGROUND AND OBJECTIVE: Modern techniques of automated perimetry have shown that surgical reduction of intraocular pressure (IOP) may have a beneficial effect on the glaucomatous visual field. The purpose of the present study was to analyse and quantify the changes in the visual fields of glaucoma patients after trabeculectomy. MATERIALS AND METHODS: Octopus visual fields of twenty-seven glaucoma patients were analysed. Change in visual field mean sensitivity (MS) was calculated to detect total field changes. A clinical and a statistical analysis of small clusters of test points were used to define whether local changes had occurred. RESULTS: MS in the operated eyes improved significantly from 16.4+/-5.6 to 18.2+/-5.5 dB. The patients had on average 3.9+/-6.2 clusters where the retinal sensitivity had improved at least 5 dB and only 0.4+/-0.9 clusters where sensitivity had deteriorated at least 5 dB after trabeculectomy. 17 patients had more improved than deteriorated clusters postoperatively. CONCLUSION: Statistically significant improvement was seen in the MS, but improvement was also found in small local areas of the visual fields after trabeculectomy.