Analysis of the AC/A ratio in myopia patients in relation to spectacles and soft contact lenses

Abstract

Purpose: To compare accommodative convergence over accommodation (AC/A) ratio when Myopic patient changes from Spectacles to Contact lenses. Methods: A prospective, cross-sectional study group of 50 subjects and Myopic error from -0.75DS to - 6.00DS. The AC/A ratio was measured by two methods; the heterophoria method and the gradient method. Gradient method was measured by plus and minus Lenses technique. Heterophoria in near and distance was measured to calculate heterophoria method. Wilcoxon Signed Ranks Test was used to compare between two methods p value < 0.05. Result s : The mean AC/A ratio in Gradient method when using Soft Contact Lenses in comparison to Spectacles was: with+3(2.21, 2.24), and with-3(1.51,150) respectively. Although the AC/A ratio was less in amount with +3D lens in near and more in distance with -3D lens as compared to Spectacles, there were no significant differences found between the two (P:0.285 and P:0.317 respectively). The means of AC/A ratio as calculated by Heterophoria method was increased with soft contact lenses (5.97) as compared to spectacles (5.96) with no significant difference p: 0.317 Conclusion: No significant difference has been found for myope when changing from spectacles to contact lenses.