Clinical Characteristics and Associated Factors to the Development of Glaucoma in Eyes With Myopic Optic Neuropathy

Abstract

Purpose

To observe the development of glaucoma in myopic eyes with and without myopic optic neuropathy (MON) and analyze associated factors to the development of typical glaucomatous damage.

Design

A prospective, observational, cohort study

Methods

A total of 233 myopic eyes with no definite evidence of glaucomatous damage were included in the study. Myopic patients without any retinal nerve fiber layer (RNFL) or visual field (VF) abnormalities were classified as myopic eyes without MON. Myopic patients with decreased RNFL at the superonasal (SN) or nasal area, and with corresponding VF defects either in the temporal or inferotemporal (IT) region, which is different from glaucomatous damage, were classified as myopic eyes with MON. Myopic eyes that developed glaucoma were defined by the presence of glaucomatous VF in the SN region including defects in Bjerrum area, or a new localized RNFL defect in the IT region on red-free photography or RNFL OCT. Disc morphological features and optic nerve head (ONH) parameters of two groups were compared. Hazard ratios for the association between baseline factors and conversion to glaucoma were obtained using Cox regression analysis.

Results

Mean follow-up period was 11.66 ± 2.86 years. Myopic eyes with MON had a thinner average peripapillary RNFL thickness (P < 0.001), worse MD of the VF (P = 0.031), a higher percentage of IT VF defects (P < 0.001), smaller torsion degree (P = 0.047), and greater LCD (P = 0.022). Myopic eyes with MON who developed glaucoma had a thinner average peripapillary RNFL thickness (P = 0.009), greater PPA area (P = 0.049), greater LCD (P < 0.001), and thinner LCT (P < 0.001). Thinner baseline temporal RNFL thickness (HR, 0.956; 95% CI, 0.928–0.986; P = 0.004), greater baseline LCD (HR, 1.003; 95% CI, 1.000–1.005; P = 0.022), and greater PPA area (HR, 1.000; 95% CI, 1.000–1.003; P = 0.050) were significantly associated factors with glaucoma development in the Cox regression analysis.

Conclusion

Myopic eyes with MON have a greater risk to develop glaucoma compared to myopic eyes without MON. Myopic eyes with MON had larger PPA area, greater LCD, and thinner temporal peripapillary RNFL, indicating that accompanying structural weakness due to myopia, especially at the temporal side of the optic nerve head and the peripapillary sclera, increases the risk of glaucoma in myopic eyes with MON.