Influence of surgical reduction of intraocular pressure on regions of the visual field with different levels of sensitivity.

Abstract

To determine whether the ability to document improvement in visual fields after intraocular pressure (IOP) reduction can be enhanced by focusing on regions of the field with different levels of sensitivity. Cohort study. This is a retrospective study. Yale Eye Center. The visual fields (Octopus G2) of 30 eyes of 30 patients undergoing trabeculectomy. Visual fields were evaluated a mean of three months before and 7.8 months after surgery. Change in sensitivity between the preoperative and postoperative visual fields (Delta S) was evaluated globally by comparing all 59 points of sensitivity and regionally in three groups according to preoperative sensitivity (pre-S): 25% of highest, 50% intermediate, and 25% of lowest points of sensitivity. Improvement in Delta S was also correlated with preoperative mean defect (pre-MD), percent intraocular pressure (IOP) reduction (Delta IOP%), and patient's age. Six visual fields showed improvement in Delta S when evaluated globally and nine showed improvement in pre-S subgroups. Of the latter, all nine showed improvement in the subgroup with the lowest pre-S, and two in the intermediate subgroup, but none in the subgroup with the highest pre-S. Combining the subgroups with the lowest pre-S and the highest Delta IOP% was associated with the highest mean Delta S. The ability to document improvement in visual fields following surgical reduction of IOP may be enhanced by focusing on subgroups of test points with lower baseline sensitivity.