Evaluation of contrast sensitivity function for ametropia corrected by either spectacles or rigid gas permeable contact lenses

Abstract

Objective To test the contrast sensitivity function (CSF) for ametropes corrected by either spectacles or rigid gas permeable contact lenses (RGPCLs).Visual performance and visual quality under the different corrective methods were compared and analyzed. Methods Fifty-six ametropic patients (100 eyes,myopia range:-1.00～-13.00 D,astigmatism range:0.50～3.75 D) were enrolled and fully corrected by either spectacles or RGPCLs. The best corrected logMAR visual acuities (BCVA) were examined.CSF with and without glare was measured with CSV-1000E.The area under the log contrast sensitivity function (AULCSF) was calculated from the contrast sensitivity data.A paired t test was used to compare best corrected visual acuity,CSF at each spatial frequency as well as the AULCSF for the two conective methods.Results The BCVA for eyes wearing spectacles or RGPCLs were 0.019±0.032 and 0.004±0.013, respectively, a significant difference was found (t=-3.82,P＜0.01).The CSF values for RGPCLs were higher than spectacles at all spatial frequencies with and without glare (all P＜0.05).The AULCSF for spectacles and RGPCLs were 1.171±0.028,1.344±0.018 without glare,and 1.143±0.022, 1.268±0.025 with glare,there were significant differences for the two corrective methods with and without glare (t=-4.03,-3.13,P＜0.01).Conclusion RGPCLs are not only provide better visual acuity than spectacles but also improve contrast sensitivity function at all spatial frequencies. The RGPCL offers better visual quality and improves visual function for ametropia patients. Key words: Contact lenses,rigid gas permeable; Contrast sensitivity; Photopic