Ability of peripapillary atrophy parameters to differentiate normal-tension glaucoma from glaucomalike disk

To investigate the ability of peripapillary atrophy (PPA) parameters to differentiate normal-tension glaucoma (NTG) from glaucomalike disk (GLD).

Thirty-three eyes of 33 patients with GLD that had no evidence of visual field defect and retinal nerve fiber layer defect and 33 eyes of 33 patients with NTG, matched with age and intraocular pressure, were enrolled. The participants were selected from the database of patients referred from a routine health checkup because of high cup-to-disk ratio (>0.5). Topographic measurements for the optic disk were performed using the Heidelberg Retina Tomograph (HRT). The extent of PPA (zone beta) was measured with Atrophy Zone Analysis software of HRT. Receiver operating characteristic (ROC) curves (GraphROC version 2.0) were used to compare the new formula including PPA parameters with that of the HRT discriminant analysis formula in differentiating NTG from GLD.

The area of zone beta, atrophy-to-disk area ratio, and angular and radial extent of zone beta were significantly larger in NTG (P < 0.01). Multiple logistic regression analysis showed that rim area and corrected radial extent of zone beta are variables that show significant difference between NTG and GLD (P < 0.05). The area under the ROC curve for the new formula including rim area and corrected radial extent of zone beta (0.8655) was significantly larger than that for the HRT discriminant analysis formula (0.7351) (P = 0.0128).

The PPA measurement obtained by HRT can be a useful additional tool to differentiate NTG from GLD after the first screening by disk photograph in a routine health checkup.