Color Vision Improvement Following Successful Trabeculectomy

Abstract

Abstract: : Purpose:To determine if color vision improves following reduction of intraocular pressure after trabeculectomy. Methods: Medical records of 41 glaucoma patients (63 eyes) were reviewed. The inclusion criteria were more than four visits at the Glaucoma service, thorough eye exam including Farnsworth–Munsell 100 Hue color vision test (FM–100 HT) and Goldmann applanation tonometry with diurnal curve. The color vision was tested separately for each eye by Macbeth lamp with standard color temperature of 6500K and color vision parameters like Achromatic Score, Total Error Score, Yellow–Blue defect and Red–Green defect were measured.There were one study group and two control groups. The study group, consisted of 21 eyes of glaucoma patients who underwent uncomplicated trabeculectomy and achieved an IOP reduction of at least 20% of baseline level.Control group A consisted of 21 eyes of age–matched glaucoma patients( with study group) who received medication and/or underwent surgery but IOP was not reduced by 20 % of baseline level.Control group B consisted of 21 eyes of glaucoma patients matched by baseline color vision scores( with study group) and received medication and/or underwent surgery with IOP reduction of less than 20% of baseline level. FM–100HT was measured at least two times before treatment (the first color vision test was excluded to minimize learning effect) and at least one time three months after IOP stabilization. The percentage of IOP reduction was compared with changes in above mentioned color vision parameters in the study group and between the study group and control groups. Results: There was a statistically significant improvement in color vision parameters of Total Error Score, Red–Green, Overall Achromatic Error (p<0.001) and Yellow–Blue defect (p= 0.007) in study group compared to control group A. The improvement of color vision parameters of Error Score (r=0.518, p<0.001), Red–Green (r=0.547, p<0.001), Yellow–Blue (r=0.402, p=0.008) and Overall Achromatic Error (r=0.562, p<0.001) was correlated with percentage of IOP reduction. The study group and control group B also showed a statistically significant difference in both the final color vision scores and in the change in color vision parameters after treatment (p<0.05). Conclusions: Intraocular pressure reduction of 20% following trabeculectomy was associated with an improvement in color vision and it can be used as a useful marker to assess the effect of treatment.

Keywords: color vision • intraocular pressure • clinical (human) or epidemiologic studies: outcomes/complications