Influence of cataract surgery on automated perimetry in patients with glaucoma

Abstract

PURPOSE: To investigate the influence of cataract surgery on automated perimetry in patients with glaucoma. DESIGN: Interventional case series. METHODS: A total of 105 eyes of 105 consecutive patients with glaucoma who were scheduled for cataract surgery underwent Humphrey static threshold testing (30-2 program) before and at 1 month after surgery. These eyes were divided into two groups based on the presence of absolute or near absolute (dense) scotomata before surgery (minimum threshold value 5 decibels or less). Changes in numbers of the dense scotomata, mean deviation, pattern standard deviation, and corrected pattern standard deviation were analyzed. RESULTS: No significant changes were found in the numbers of dense scotomata and central dense scotomata within five-degree visual fields between before and after surgery. In the group with dense scotomata, the mean pattern standard deviation and corrected pattern standard deviation worsened significantly after surgery, whereas the mean deviation improved significantly. However, in the group without dense scotomata, the pattern standard deviation and corrected pattern standard deviation showed a slight improvement, whereas the mean deviation improved significantly. When the central scotoma was present in two or fewer meridians before surgery, the mean visual acuity after surgery reached 20/25 and was better than that in patients with three or four central scotomata ( P = .0014). CONCLUSIONS: Cataract does not produce a dense scotoma on automated perimetry. However, because it does produce relative scotomata, actual glaucomatous visual field defects may be hidden to some extent. When a central dense scotoma is present before surgery in two or fewer meridians, the patient may well achieve substantial improvement in postoperative visual acuity.