Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

Objective: To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia.

Methods: Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD.

Results: Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7 years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p < 0.001) and less SE (-7.8 ± 2.7 vs. -5.4 ± 2.5 diopters, p < 0.001). Greater tilt ratio (odds ratio (OR) = 4.9, p < 0.001), less SE (OR = 0.708, p < 0.001), and thinner average RNFL (OR = 0.910, p = 0.001) were significantly associated with GOD. Among 934 normal eyes, 366 (39.2%) displayed disc torsion, while among 26 glaucomatous eyes, eight (30.8%) displayed disc torsion.

Conclusions: Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.