Prognostic Factors for Axial Length Elongation and Posterior Staphyloma in Adults With High Myopia: A Japanese Observational Study.

PURPOSE: To identify prognostic factors for axial length (AL) elongation and incidence of posterior staphyloma (PS) in adult Japanese patients with high myopia. DESIGN: Retrospective, observational cohort study. METHODS: Six-year follow-up data for 345 patients (620 eyes with AL ≥ 26.5 mm and spherical equivalent [SE] ≤- 8.00 diopters) admitted to the Tokyo Medical and Dental University Hospital from 2007 to 2017 were analyzed retrospectively. Main outcome measures were change in AL from baseline, factors associated with AL, categorization of eyes with high myopia, factors associated with incidence of PS, and impact of PS on myopic maculopathy and visual function. RESULTS: The mean annual increase in AL was 0.03 mm. Presence of optic nerve disc conus (P = .025), steeper corneal curvature, lower SE, and decreased choroidal thickness (CT) (all P < .001) were associated with increased AL in univariate and multivariate analyses. Younger age (P = .003) and no use of intraocular pressure-lowering medications (P = .046) were associated with increased AL. Eyes with high myopia were categorized using factor analysis as associated with glaucoma, severe pathologic myopia, and mild-to-moderate pathologic myopia. Older age, increased AL, glaucoma, and choroidal thinning (all P ≤ .001) were identified as significant risk factors for the incidence of PS in univariate and/or multivariate analyses. Incidence of PS was a precursor for myopic maculopathy and visual field defects. CONCLUSIONS: Optic nerve disc conus, steeper corneal curvature, lower SE, decreased CT, and no use of intraocular pressure-lowering medications were prognostic factors for increased AL. Older age, increased AL, glaucoma, and decreased CT were prognostic factors for PS.