Progression of Glaucoma in a multicentre cohort of patients

Abstract

 

Purpose

 

To study glaucoma progression in a cohort of open angle glaucoma patients.

 

Methods

 

We conducted a multicentre retrospective database review of patients diagnosed with primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). Data obtained included disease duration (DD), Humphreys visual fields 24-2 (HVF) mean deviation (MD) and cup:disc ratio (CDR). Glaucoma was staged using Hodapp-Parish-Anderson criteria as early(MD≥ -6dB), moderate(MD<-6dB to -12dB) and severe(MD<-12dB). We studied the glaucoma progression in a subset of 30 glaucoma patients equally distributed in 2 groups of 15 each. Both groups were comparable in age. Group1 had early glaucoma and group2 had moderate-severe glaucoma. MD recorded at diagnosis, 3 and 5 years were noted. Pearson correlation and paired t-tests were used for statistical analyses.

 

Results

 

Data obtained for 870 patients included 727 (83.6%) with POAG and 143 (16.4%) with NTG. The mean DD was 8.42 ± 8.34 years. The mean MD in the POAG group was -9.06 ± 7.81 and in the NTG group -7.44 ± 7.11. Independent correlation analysis of POAG and NTG showed there was a statistically significant positive correlation of DD with CDR and negative correlation with MD (n=727, p<0.001, 2-tailed) in the POAG group.This suggests that progression in optic disc cupping and worsening of MD of HVF corresponds to DD. Conversely the NTG group showed no correlation between DD and CDR although a significant negative correlation was noted between DD and MD (n=143, r=-0.316, p<0.001, 2-tailed). In the subset group 1 a mean baseline MD of -2.8 ± 1.66 dB deteriorated by a mean 1.41 ± 1.67 dB (p=0.006), in the initial 3 years and by a mean of 1.46 ± 1.28 dB (p=0.001) in the next 2 years. In group 2 a mean baseline MD -13.46 ± 4.55 dB deteriorated by a mean of 2.69 ± 2.70 dB (p=0.002) in the initial 3 years and thereon by a mean of 1.38 ±2.29 dB (p=0.035).

 

Conclusions

 

Our results suggest that DD correlates well with optic disc and HVF changes in POAG but only with HVF changes in NTG. In our subset we noted the mean deterioration in HVF between baseline and year 3 in group 2 was greater than group 1(although not significant, p=0.3). This may suggest that HVF in advanced glaucoma deteriorate rapidly. This will be evaluated in future studies with larger numbers of patients. The above phenotypic differences may be due to underlying different genetic variants contributing to these phenotypic subsets of open angle glaucoma.

 

 

 

Keywords: 758 visual fields • 627 optic disc • 568 intraocular pressure