Significant Improvement in Dynamic Visual Acuity after Cataract Surgery: A Promising Potential Parameter for Functional Vision

PURPOSE: Dynamic visual acuity (DVA) is a relatively independent parameter for evaluating the ability to distinguish details of a moving target. The present study has been designed to discuss the extent to which age-related cataract impacts DVA in elderly individuals and to determine whether it could be restored after bilateral phacoemulsification combined with intraocular lens implantation surgery. METHODS: Twenty-six elderly cataract patients scheduled for binocular cataract surgery and 30 elderly volunteers without cataract were enrolled in the study. DVA at 15, 30, 60 and 90 degree per second (dps) was assessed, and velocity-dependent visual acuity decreases between consecutive speed levels were calculated. RESULTS: Compared with the control group, the patient group exhibited significantly worse DVA performance at all speed levels (p<0.001), and the decreases in velocity-dependent visual acuity were more serious in the patient group at the intervals of 0–15 dps (p<0.001), 15–30 dps (p = 0.007) and 30–60 dps (p = 0.008). Postoperatively, DVA performance at every speed level in the patient group clearly improved (p<0.001) and recovered to levels compatible to the control group. The decrease in visual acuity with increasing speed was less pronounced than during the preoperative phase (p(0–15 dps) = 0.001, p(15–30 dps)<0.001 and p(30–60 dps) = 0.001) and became similar to that of the control group. The postoperative visual benefit regarding DVA was more pronounced than the improvement in static visual acuity (p(15 dps) = 0.001 and p<0.001 at 30 dps, 60 dps and 90 dps). CONCLUSIONS: The impact of age-related cataract on DVA was more severe than its effects on static visual acuity. After cataract surgery, not only static vision of the patients was restored markedly, but also the dynamic vision. DVA could be an important adjunct to the current evaluation system of functional vision, thereby meriting additional attention in clinical assessment.