Rate of progression of visual field loss in primary open angle glaucoma versus primary angle closure glaucoma patients managed in a Tertiary Hospital

ABSTRACT

@#OBJECTIVES: To compare the rate of progression of visual field loss in mean defect (MD) decibels (dB)/year in primary open angle glaucoma (POAG) versus primary angle closure glaucoma (PACG) patients managed in a tertiary hospital and to assess the impact of baseline age, baseline MD, and intraocular pressure (IOP) on the rate of progression of visual field loss. METHODS: This was a retrospective review of medical records of patients who were seen at the Glaucoma Clinic of a tertiary hospital from August to October 2018. The following data were recorded diagnosis, number of reliable automated visual fields (AVFs), number of years followed, baseline age, baseline MD, MD of all subsequent AVFs, IOP at the time of each test, and IOP-lowering interventions. Rate of visual field progression expressed in dB/year was calculated using linear regression analysis. T–test was done to compare the baseline data and rates of progression of visual field loss between the POAG and PACG cohorts. Correlation using Pearson’s r and multivariate analyses were performed to evaluate the effect of baseline age, baseline MD, and IOP on rate of progression of visual field loss. RESULTS: The mean rates of progression of visual field loss in POAG and PACG eyes were 0.12 ± 0.68 dB/year and 0.10 ± 0.59 dB/year, respectively (p=0.8525). Despite treatment, 4.35% of the study eyes were identified as fast progressors while 1.09% were catastrophic progressors. In the POAG group (n=33), laser treatment was negatively correlated with rate of progression of visual field loss (r= -0.5072, p=0.0026). Multivariate analysis showed that baseline MD (p=0.017), mean IOP on follow–up (p=0.020), and laser treatment (p=0.004) were significant factorsaffecting the rate of progression of visual field loss in POAG eyes. In the PACG group (n=59), both baseline MD (r= -0.2798, p=0.0318) and mean IOP on follow–up (r= 0.368, p=0.0041) correlated with rate of progression of visual field loss. Only mean IOP on follow–up was found to be significant on multivariate analysis. CONCLUSION: While most glaucoma patients managed in a tertiary hospital have a slow rate of progression of visual field loss, a few were still identified as fast and catastrophic progressors. Factors associated with rate of progression of visual field loss were baseline MD, mean IOP on follow–up, and laser treatment for POAG, and mean IOP on follow–up for PACG.