Abstract:

Objective      To investigate changes of low contrast visual acuity and its correlation with temporal optic disc parameters of the neuroretinal rim measured with Heidelberg retinatomography(HRT-Ⅱ) in the aged population with primary glaucoma. Methods      83 eyes from 45 patients with primary glaucoma and 40 eyes from 23 healthy subjects were examined with HRT-Ⅱ for optic disc parameters of the rim area(RA) and rim volume(RV) .Their corrected visual acuity at 100％, 25％, 10% and 5％ contrast levels in bright background were measured with a multifunctional visual acuity analyzer. According to the mean defect (MD) of visual field, glaucomatous patients were divided into the early glaucoma group(21 cases, 40 eyes) and the moderate and severe glaucoma group(24 cases, 43 eyes). The corrected visual acuity at 25％, 10% and 5％ contrast levels was compared among the normal group and the two glaucomatous groups. Correlations were evaluated between the corrected visual acuity at the three low contrast levels and the temporal disc parameters of RA and RV in each glaucomatous group. Results      There were statistical differences in corrected visual acuity at 25％, 10% and 5％ contrast levels among the three groups(P<0.05). The corrected visual acuity at three low contrast levels in both the normal group and the early glaucoma group were significantly better than in themoderate and severe glaucoma group (P<0.05). There was no statistical difference between the early glaucoma group and the normal group(P>0.05). The corrected visual acuity at 10％ and 5％contrast levels in the moderate and severe glaucoma group was negatively correlated with temporal RA(r=-0.361； r=-0.318, P<0.05) and RV (r=-0.303；r=-0.377, P<0.05). Conclusions      The visual acuity at low contrast levels declines in the aged population with advanced primary glaucoma. In moderate and severe glaucomatous patients，the visual acuity at 10％ and 5％contrast levels is correlated with temporal optic disc parameters of the neuroretinal rim measured with HRT-Ⅱ. The examination of low contrast visual acuity may be an effective method for assessing the damage of glaucoma and its progression.

Key words: Glaucoma； Low contrast visual acuity； Heidelberg retinatomography-Ⅱ(HRT-Ⅱ)