Abstract
Abstract: :
Purpose: To examine and compare the inter-ocular asymmetry in visual field defects of patients with POAG (Primary open angle glaucoma) and PACG (Primary angle closure glaucoma). Methods: Subjects in a prospective, randomised, placebo-controlled trial of per-operative 5-fluorouracil in glaucoma surgery in Singapore were included. All subjects with primary glaucoma over 30 years of age undergoing trabeculectomy were prospectively considered for inclusion. Pre-operative visual field testing was performed with the Humphrey Perimeter Mk II, 750. A minimum of two tests were required with: mean deviation within 2dB on two tests, fixation losses <20%, false positives <20% and false negatives<33%. The fields were scored using AGIS II criteria and the 'mean asymmetry score' defined as the mean difference between eyes for both AGIS scores and global indices. These mean asymmetry scores were compared for POAG and PACG and Spearman rank correlation used to examine the relationship between right and left eyes of in each group. Results: 230 subjects were assessed, 128 POAG, 102 PACG. There was no significant correlation of field severity between eyes in PACG (AGIS: Spearman = 0.02, p = 0.85 MD: Spearman = 0.15, p = 0.89) whereas POAG showed a significant correlation (AGIS: Spearman 0.27, p = 0.003 MD: Spearman = 0.27, p = 0.003). Inter-ocular asymmetry scores of visual field loss were greater for the PACG group. Mean AGIS asymmetry scores for total (PACG =9.21 ±6.87; POAG =6.48 ±5.58 , p=0.001), superior (PACG =4.31 ±3.39; POAG =3.35 ±3.13 , p=0.035), and inferior (PACG =4.43 ±3.31; POAG =2.64 ±2.77 , p<0.0001) areas and Mean Deviation asymmetry scores (PACG =6.89 ±13.22; POAG =1.66 ±16.97, p=0.012) were all significantly different. Conclusion: There may be a greater asymmetry of visual field loss between eyes in PACG than there is in POAG, as measured by AGIS scores and global indices. This would be consistent with a more rapid rate of visual loss in PACG.
Keywords: 624 visual fields