Biometric Features of Peripapillary Atrophy Beta in Eyes with High Myopia

Abstract

To evaluate peripapillary atrophy β (PPA-β) characteristics in highly myopic eyes, using simultaneous confocal scanning laser ophthalmoscopy (cSLO) and enhanced spectral-domain optical coherence tomography (SD-OCT). The authors retrospectively analyzed 61 highly myopic (≥ -6.0 D) eyes without myopic retinopathy. cSLO fundus images were used to measure the distances from the foveal center to the temporal and nasal margins of the PPA-β zone; horizontal cross-sectional SD-OCT images, to determine the position where the inner plexiform layer (IPL) terminates within the PPA-β zone; and A-mode ultrasonography, to measure axial length. The distance from the foveal center to the PPA-β zone temporal margin (2.68-4.39 mm) correlated with the circumferential extent of PPA-β (P <0.001, r = -0.49). The distance from the foveal center to the nasal margin (3.41-5.60 mm) correlated with the ovality index of the optic disc (P <0.001, r = -0.51) and with the axial length (P <0.05, r = 0.26). PPA-β zone width (0.20-2.05 mm) correlated with the circumferential extent of PPA-β (P <0.001, r = 0.42), ovality index of the optic disc (P <0.001, r = -0.68), and axial length (P <0.05, r = 0.32). The IPL termination within the PPA-β zone was significantly closer to the optic disc when the circumferential extent of PPA-β was large (P <0.01, r = 0.36). Interindividual variations in biometric features of PPA-β in highly myopic eyes showed different associations with axial length, degree of disc ovality, and circumferential extent of PPA-β.