Perimetric Progression in Glaucoma Patients : Asymmetry of Right v Left Eye

Purpose:To assess the asymmetry of visual field (VF) progression rate in glaucoma patients. Methods:In this retrospective study both eyes of 219 patients with primary open-angle glaucoma (POAG) having a follow-up of at least 5 years with at least one VF test per year were included. Patients with unreliable VF, learning effect, other forms of glaucoma or other factors that could affect the Humphrey Field Analyzer Mean Defect (MD) other than glaucoma were excluded. Progression was defined as the MD slope at regression analysis for each VF series. For each patient, the difference in the slopes of right and left eye was calculated and compared by means of regression analysis and t-test. Results:The mean follow-up was 79 months. In right and left eyes MD was, respectively, -6.32 ± 7 dB and -6.25 ± 6.5 dB at baseline, -8.45 ± 7.4 dB and -8.75 ± 7.32 dB at the end of the study, with a change of -2.13 ± 3.9 dB and -2.50 ± 3.5 dB. MD slope of right and left eyes was, respectively, -0.32 dB and -0.37 dB per year. Although right eyes tended to have a higher progression (y = 0.32x -1.83; R² = 0.12), such an asymmetry was not statistically significant (P = 0.30). The study was powered 80% to detect a difference of 0.2 dB per year. Conclusions:We found that perimetric progression in the right and left eyes of patients with POAG was not different over a 5 years period.