Characteristics Of Focal Gamma Zone Parapapillary Atrophy

PURPOSE. The purpose of this study was to investigate the characteristics of focal.-zone parapapillary atrophy (focal gamma PPA) in patients with primary open-angle glaucoma (POAG) using spectral-domain optical coherence tomography (SD-OCT).METHODS. Three groups of POAG eyes (n = 214) were defined according to the circumferential extent of Bruch's membrane (BM) within the beta-zone PPA, as follows: (1) no PPA (intact BM; n = 81), (2) conventional gamma PPA (gamma PPA involving the fovea-BM-opening axis; n = 89), and (3) focal gamma PPA (gamma PPA not involving the fovea-BM-opening axis; n = 44). Clinical and ocular characteristics, including age, axial length (AXL), and focal lamina cribrosa (LC) defects were compared among the three groups.RESULTS. The focal.PPA group was significantly older (60.6 +/- 11.0 years) and had shorter AXL (24.10 +/- 1.34 mm) than those of the conventional gamma PPA group (46.2 +/- 13.8 years and 26.53 +/- 1.61 mm, respectively; P < 0.001). These values of the focal.PPA group were similar to those of the no gamma PPA group (23.73 +/- 0.97 mm for AXL and 64.0 +/- 13.0 years for age). The focal gamma PPA group had a significantly higher prevalence of focal LC defects than did the other two groups (70.5% [31/44] for the focal.PPA group versus 46.1% [41/89] for the conventional.PPA group versus 37.0% [30/81] for the no gamma PPA group; P = 0.002).CONCLUSIONS. Focal.PPA was differentiated from conventional.PPA by older age and shorter AXL. Further, focal.PPA was frequently accompanied by focal LC defects. Longitudinal studies elucidating whether focal LC defects and focal.PPA share common pathogenesis are warranted.