Mean difference of visual acuity with auto refraction and subjective refraction.
Purpose: To compare the mean difference of visual acuity as measured by auto refraction and subjective refraction.
Study Design: Descriptive cross-sectional study.
Place and Duration of Study: Department of ophthalmology, Services hospital Lahore from November 2013 to April 2014.
Material and Methods: Using non-probability consecutive sampling 300 eyes of 300 patients fulfilling inclusion criteria were recruited through OPD registration slip. Demographic data including age and gender was recorded. Complete ophthalmic examination was performed. This included measurement of refractive error by auto-refraction as well as subjective refraction. Detailed anterior segment examination with slit lamp and dilated fundus examination with indirect ophthalmoscopy was performed. The collected data was analyzed by using software SPSS version 17.
Results: The mean age of patients was 34.71 ± 7.45 years. There were 156 (52%) males and 144 (48%) females. There were 263 (87.69%) patients who had visual acuity of 6/6 and 37 (12.33%) had 6/9. Mean spherical auto-refraction and subjective refraction was 0.0290 ± 2.58 and -0.2842 ± 2.37 D with mean difference of -0.3133 ± 1.27 D. The mean cylindrical auto and subjective refraction in this study was -.9742 ± 0.78 D and -0.7500 ± 0.81 D and mean difference was 0.2242 ± 0.74 D. The mean cylindrical axis of auto and subjective refraction was 114.88 ± 49.75 and 115.60 ± 49.70 with mean difference as 0.72 ± 3.02 D (p-value < 0.05).
Conclusion: Difference of spherical, cylindrical and cylindrical axis in auto and subjective refraction was significantly different.