Non-pathologic components are associated with reduced visual acuity in myopes after spectacle correction.

Purpose: To find the association between reduced best-corrected visual acuity and non-pathologic components after optical correction in individuals with low to high myopia.

Methods: Myopic children under 16 years of age were reviewed using electronic medical records and the following data were extracted and recorded: participant's age, gender, uncorrected visual acuity (UCVA), manifest refraction, and best corrected visual acuity (BCVA). Spherical equivalent and cylinder were classified into low, moderate, and high categories based on the magnitude range. Similarly, astigmatism was defined into with-the-rule, against-the-rule, and oblique based on the location of the steepest meridian. Reduced BCVA was defined when the decimal visual acuity was less than 0.66 (equivalent to Snellen's acuity of 6/9 or 20/30). Logistic regression was performed to test the factors associated with reduced visual acuity after optical correction in the absence of myopic pathologic changes. Statistical significance was considered if P < 0.05.

Results: Overall 44.9% (N = 242/538) of myopes had reduced best-corrected visual acuity (BCVA) and none of the patients had pathologic myopic lesions. Using logistic regression, we found that high spherical refraction (OR 27.98, 95% CI 14.43-54.25, P < 0.001) and moderate spherical refraction (OR 5.52, 95% CI 2.56-11.91, P < 0.001) were significantly associated with reduced best corrected visual acuity despite any pathological lesions. Additionally, oblique and ATR astigmatism were associated with reduced visual acuity in myopic children with (OR 2.05, 95% CI 0.77-5.42) and (OR 1.59, 95% CI 0.82-3.08).

Conclusion: Higher magnitude of refractive error components causes reduced visual acuity in the absence of pathologic changes.