Complications of pathologic myopia in the longer eye of patients with anisomyopia foretell similar complications in the shorter anisomyopic eyes, a study published in the British Journal of Ophthalmology shows. The research also points to a significant population of patients with high myopia (HM) and anisomyopia who have pathologic myopia (PM).
The cross-sectional study investigated patients with high myopia at a single, hospital-based eye clinic to determine the prevalence of anisomyopia (defined as an axial length [AL] difference ≥2.5 mm), among individuals with high myopia (defined as a spherical equivalent of ≤6.0 diopters [D] or AL ≥ 26.5 mm). They also evaluated if complications of pathologic myopia in the longer anisomyopic eye (LAE) is associated with increased risk of complications of pathologic myopia in the shorter anisomyopic eye (SAE).
The team conducted biometry, fundus photography and swept-source optical coherence tomography to identify patients with high axial anisomyopia and used multivariate regression to test associations between pathologic myopia in the LAE and complications of pathologic myopia in the SAE.
The researchers found that 184 of 1168 patients met the inclusion criteria, yielding a prevalence of anisomyopia of 15.8%. These patients (mean age ± standard deviation [SD], 65.8±13.5 years) were predominantly women (71.2%), and 92.4% were Chinese.
In patients’ LAEs, the mean AL was 30.6±2.0 mm, and in their SAEs, it was 26.2±2.3 mm. The team found 52.7% of SAEs had AL narrower than 26.5 mm.
In the SAEs, the researchers observed a prevalence of 52.2% for myopic macular degeneration, 36.5% for macula-involving posterior staphyloma, 13.0% for myopic traction maculopathy, and 8.2% for myopic choroidal neovascularization (mCNV).
In the multivariate analysis controlling for confounding variables, they found complications of pathologic myopia including macular hole in the LAE was associated with increased risk of myopic traction maculopathy in the SAE (odds ratio [OR], 4.88; 95% confidence interval [CI], 1.42-16.85; P =.01). They also found associations between the presence of mCNV in the LAE with the same complication of pathologic myopia in the SAE (OR, 3.57; 95% CI, 1.18-10.79; P =.02), and posterior staphyloma in the LAE with that in the SAE (OR, 4.03; 95% CI, 1.89-8.62; P <.001).
“In anisometropic PM, given our findings, it is reasonable to believe that the SAE is also at risk of PM complications and should be watched closely; anisometropic HM, on the other hand, may be more likely to follow a benign course with the SAE maintaining good vision in the long term,” the researchers report.
Limitations of the study included the single-center, hospital-based, cross-sectional design and inability to use refraction data in our inclusion criteria or analysis due to cataract extraction in some patients.
Li J, Dan YS, Chua SQ, et al. Pathologic myopia in highly myopic patients with high axial anisomyopia. Published online January 23, 2023. Br J Ophthalmol. doi:10.1136/bjo-2022-322285