Glaucoma Filtering Surgery Decreases the Rate of Visual Field Progression

Abstract

Purpose: : Glaucoma filtering procedures produce greater IOP reduction and less IOP fluctuation than medical treatment. We evaluated the efficacy of glaucoma filtering surgery in decreasing rates of visual field (VF) progression.

Methods: : We evaluated the charts of glaucoma patients with ≥10 SITA-Standard VFs who underwent successful glaucoma surgery (not requiring further surgical intervention) in either eye with a minimum follow-up period of 2 years. Patients with other ocular conditions known to affect the VF, and insufficient number of VFs to create a slope, were excluded. Pointwise linear regression analysis (Progressor®) was used to calculate global and localized rates of progression. A test point was identified as progressing if the slope of sensitivity over time exceeded 1 dB loss/year with p<0.01. Comparisons were performed within the same eyes (Student’s paired t-test) before and after surgery.

Results: : 28 patients (28 eyes, mean age: 61.2±14.5 yrs) were enrolled. Mean number of VFs was 13.4±4.8, spanning 7.1±1.2 yrs (range 4-9 yr). The mean global rate of progression decreased from 1.45±1.4 to 0.57±1.0 dB/yr (64% reduction, p=0.01). The mean progression rate of points demonstrated to have been progressing before surgery decreased from 2.47±1.7 to 0.13±0.4 dB/yr (94% reduction, p<0.01).

Conclusions: : Glaucoma surgery significantly reduces VF progression rates. This was more pronounced in points with faster progression prior to surgery.

Keywords: visual fields