Amblyopia may have protective effect against Age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of visual impairment with 200 million patients affected globally. Amblyopia is a neurodevelopmental abnormality that leads to reduced vision usually in one eye. It is clinically defined as a difference between eyes in best-corrected visual acuity of two lines or more. The prevalence of amblyopia varies widely among regions and periods.

Researchers aimed to evaluate whether patients with AMD and co-occurrent amblyopia are more likely to have both diseases diagnosed on the ipsilateral or on the contralateral side in a large Austrian database.

A review in The American Journal Of Opthalmology reveals that database of patients with age-related macular degeneration (AMD) and amblyopia showed that, among patients with asymmetrical AMD and amblyopia, there was a greater likelihood of AMD to be more advanced in the non-amblyopic eye. The possible protective effect of amblyopia on the development of AMD warrants further investigation.

Researchers evaluated medical records of all patients who visited the Department of Ophthalmology of the Medical University Graz between December 1996 and June 2021 were searched for the co-occurrence of AMD and amblyopia. Patients with AMD diagnosed on one eye side were used for further analysis. Spectral-domain optical coherence tomography (SD-OCT) images were analyzed to confirm the lateral asymmetry of AMD.

The key findings of the study are

• A total of 327 443 patients were screened for the co-occurrence of AMD and amblyopia.

• 8742 patients had AMD diagnosed on one eye side and 5 051 patients had unilateral amblyopia.

• 163 patients were found to have AMD diagnosed on one side and unilateral amblyopia in combination.

• Out of these, 126 patients had AMD and amblyopia on contralateral sides and 37 had AMD and amblyopia on the ipsilateral side (p<0.001).

Researchers concluded that “Less amblyopic patients had AMD diagnosed on the amblyopic eye compared to the non-amblyopic eye. In cases of lateral asymmetry, the non-amblyopic eye is more likely to have the more advanced form of AMD.”

Reference: Manuel Großpoetzl, LorenzKloeckl, AndreasGuttmann, MichaelKruger, JakobGran, LukasHoeflechner, MartinaBrandner, HeikeGaugl, DomagojIvastinovic, MarleneLindner, ReginaRiedl, AndreasWedrich, EwaldLindner; Protective Effect of Amblyopia on Age Related Macular Degeneration, American Journal of Ophthalmology (2023), doi: https://doi.org/10.1016/j.ajo.2023.07.006.