Abstract
Abstract: :
Purpose: To investigate the effect of cataract extraction on the visual fields of patients with primary open angle glaucoma (POAG). Methods: Perimetrically experienced POAG patients followed in a prospective cohort study underwent automated perimetry (either 24–2 or 30–2 of the Humphrey Field Analyzer) every six months. We compared the mean of the two visual fields immediately before and immediately after phacoemulsification cataract extraction and intraocular lens implant (effect analysis). In the control analysis the mean of the first two and last two field examinations from four consecutive examinations obtained more than one year after the cataract surgery were compared. We examined both global and pointwise changes stratified according to the baseline total deviation (TD). Results: 39 eyes of 28 patients (mean age, 71 years; range, 47 – 86 years) were included. In the effect analysis, the average time between the first preoperative and the last postoperative visual field test was 19 months (range, 4 – 32 months) while that in the control analysis was 18 months (range, 12 – 30 months). The mean logMAR best corrected visual acuity (BCVA) improved significantly after surgery from 0.23 (range, 0.00 – 0.54) to 0.07 (range, 0.00 – 0.40; P < 0.001). There was a non–significant improvement in Mean Deviation (MD) after cataract surgery from a mean of –7.32 ± 4.48 dB to –7.17 ± 4.75 dB (P = 0.649). The difference in the change in MD between the effect and control analysis was not statistically significant (P = 0.753). No correlation was found between the change in BCVA and the change in MD in either the effect or control analysis (r = –0.16; P = 0.925 and r = –0.31, P = 0.058 respectively). There was, however, a strong correlation between change in foveal threshold and change in MD in the effect analysis but not in the control analysis (r = 0.67; P < 0.001 and r = 0.08; P = 0.607, respectively). The changes in pointwise TD and MD were not dependent on the respective baseline values with either the effect or control analysis. Conclusions: While there was an improvement in BCVA and foveal thresholds after cataract surgery, in this sample of POAG patients, the changes in the visual field were negligible.
Keywords: visual fields • cataract • perimetry