[Study on risk factors for progression of visual field damage in normal-tension glaucoma]

We investigated the risk factors for progression of visual field damage in normal-tension glaucoma (NTG), using multiple regression analysis with the proportional hazard model and the life-table method. Seventy-six eyes of 56 patients with untreated NTG showing minor visual-field defects, with a mean deviation (MD) of > - 5 dB by the Humphrey (30-2) STATPAC program at entry, were included in the study. Endpoints of study follow-up were defined as follows: in HFA STATPAC 2 Glaucoma Change Probability Analysis, more than 5 points which significantly deteriorated at p < 0.05 were found at 2 consequent examinations (Criterion 1) or a significant decrease in the MD value at p < 0.025 was encountered at one examination or that at p < 0.05 at 2 consecutive examinations (Criterion 2). During the follow-up period (37 months, mean), 33 eyes (42%) satisfied Criterion 1 and 23 eyes (29%) Criterion 2. When Criterion 1 was employed, peripapillary chorio-retinal atrophy/disc ratio (p = 0.023), intraocular pressure (IOP) (p = 0.03) and cup/disc ratio (p = 0.035) were identified as significant risk factors for progression of visual-field damage. When Criterion 2 was employed, Contribution of cup/disc ratio (p = 0.065) and IOP (p = 0.145) was relatively high, but not significant. These results suggested an association of IOP and local vascular risk factors with progression of visual-field damage in NTG.