Longitudinal Changes of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer in Highly Myopic Glaucoma: A 3-Year Cohort Study

Abstract

Purpose: To describe the longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGC-IPL) thicknesses in highly myopic eyes with and without glaucoma and to investigate the effects of high myopia (HM) on the sectoral patterns of pRNFL and mGC-IPL thinning.

Design: Longitudinal cohort study.

Participants: A total of 243 eyes from 243 individuals with 3-year follow-up were included in this study: 109 eyes in the HM group, 64 eyes in the open-angle glaucoma (OAG) group, and 70 eyes in the highly myopic glaucoma (HMG) group. Based on visual field assessment, 19 OAG eyes and 21 HMG eyes were determined to show progressive disease.

Methods: Mean and sectoral pRNFL and mGC-IPL thicknesses were obtained using swept-source OCT. A linear mixed-effects model was used to compare the thinning rates and percentages among groups.

Main outcome measures: Mean and sectoral thinning rates and percentages of pRNFL and mGC-IPL in HM, OAG, and HMG eyes.

Results: The mean age of the participants was 37.2 ± 11.2 years, and the mean follow-up duration was 3.2 ± 0.3 years. The mean pRNFL thickness changed at rates of -0.44 μm/year, -0.63 μm/year, and -1.17 μm/year in the HM, OAG, and HMG group, respectively (P < 0.001), whereas the mean mGC-IPL thickness changed at rates of -0.10 μm/year, -0.32 μm/year, and -0.41 μm/year in the 3 groups, respectively (P < 0.001). Temporal pRNFL thinning was faster in HMG compared with OAG (-1.24 μm/year vs. -0.45 μm/year; P = 0.002). The mGC-IPL thinning rate in each sector was not significantly different between the HMG and OAG groups (P > 0.05 for all). In contrast to OAG, HMG eyes showed greater percentage thinning rates of pRNFL in the inferior and temporal sectors, with a greater mGC-IPL thinning in the inferonasal sector.

Conclusions: The patterns of pRNFL and mGC-IPL thinning differ between HMG and OAG. In particular, faster temporal pRNFL thinning may be a distinguishing feature for identifying glaucoma in HM eyes. These findings also may enhance the understanding of the mechanisms of damage in HMG.

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Keywords: High myopia; Imaging; OCT; Open-angle glaucoma.