Prevalence of refractive errors, myopic macular degeneration, and associated risk factors in a Maltese population-based study

Abstract

Purpose: To estimate the prevalence of refractive error and myopic macular degeneration in a nationally representative sample of older adults from Malta, evaluate associations with established risk factors. Patients and Methods: This population-based cross-sectional study included 1,794 participants aged 50–80 years from Malta, recruited as part of The Malta Eye Study (response rate 44.8%). Demographic, medical, behavioral, and ocular data were collected using structured questionnaires. Standardized ophthalmic examinations were performed, including autorefraction and retinal imaging with optical coherence tomography. Refractive error was classified by spherical equivalent as myopia (< −0.50 D) and hyperopia (> +0.50 D), while astigmatism was defined as ≤ −0.75 D. Myopic macular degeneration was graded using the meta-analysis for pathologic myopia classification. Associations were assessed using multivariable logistic regression. Results: Among right phakic, surgically untouched eyes, the prevalence of emmetropia, myopia, and hyperopia was 20.0% (95% CI 18.0–22.1%), 25.1% (95% CI 23.0–27.4%), and 54.8% (95% CI 52.3–57.3%), respectively. Vector-derived average astigmatism prevalence in both eyes was 44.3% (95% CI 41.6–46.9%), with against-the-rule astigmatism being the most common pattern. Effective refractive error coverage exceeded 90% for both distance and near vision. The prevalence of any myopic degeneration in either eye was 2.6% (95% CI 1.9–3.4%). Myopia prevalence among individuals aged 50–59 years was lower than that reported in other European populations, and use of long-acting anti-muscarinic agents was associated with myopic degeneration (OR 25.70, 95% CI 1.55–426.04, p=0.023). Conclusion: This study reports refractive error and myopic macular degeneration prevalence broadly comparable to other European settings. Lower myopia prevalence among individuals aged 50–59 years may reflect complex gene–environment–behavior interactions. Further investigation of these interactions, as well as the potential impact of long-acting anti-muscarinic agents on myopic macular degeneration, is warranted, particularly in light of the wide confidence interval.