Amblyopia protects against the likelihood of age-related macular degeneration (AMD), according to a report published in the American Journal of Ophthalmology. In instances of lateral asymmetry, eyes without amblyopia are more likely to have the more advanced form of AMD, according to the report.
Researchers performed a retrospective, cross-sectional analysis consisting of patients presenting to a single center between December 1996 and June 2021. The team included participants with amblyopia and concurrent AMD and evaluated spectral domain-optical coherence tomography (SD-OCT) images to determine AMD severity. The study’s objective was to determine whether amblyopia protects against AMD development in either eye..
Among 327,443 individuals who were screened for the co-occurence of both disorders, 8742 had unilateral AMD and 5051 had unilateral amblyopia. A total of 163 patients had both disorders — 126 patients had the conditions on contralateral sides compared with 37 individuals who had them within the same side (odds ratio [OR], 0.27; 95% CI, 0.19-0.37). Best corrected visual acuity was always worse in eyes with amblyopia, regardless of whether AMD diagnosis was on the same side (P =.004) or on the contralateral side (P <.001).
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It appears that amblyopia protects against disease severity as well, the report shows. Among a subset of 154 eyes with available SD-OCT images, AMD severity was stage 1 in 2 patients, stage 2 in 15 participants, stage 3 in 1 patient, stage 4 in 31 individuals, and stage 5 in 105 participants. Disease stages were significantly different between eyes with and without amblyopia and more advanced on the side of AMD diagnosis, according to the report.
“We found significantly fewer patients to have amblyopia and AMD on the ipsilateral eye than on contralateral sides,” according to the study authors. “Furthermore, we found that amblyopic eyes show milder forms of AMD. (…) Thus, amblyopia may also lead to a reduced metabolic activity in the retina, causing less accumulation of degradation material like lipofuscin, which would otherwise contribute to AMD pathogenesis by oxidative stress-induced damage to the retinal pigment epithelium.”
Despite these findings, the researchers state that the protective effect of amblyopia on AMD warrants further investigation.
Study limitations include a retrospective nature, an inability to access SD-OCT scans for all participants, and an absence of orthoptic exam data.
Reference
Großpoetzl M, Kloeckl L, Guttmann A, et al. Protective effect of amblyopia on age-related macular degeneration. Am J Ophthalmol. Published online July 9, 2023. doi:10.1016/j.ajo.2023.07.006
This article originally appeared on Optometry Advisor
