[Studies on prediction of visual function of vitreous opacity patients by Vernier hyperacuity tests]

To evaluate the clinical value of visual function with vitreous opacity patients preoperatively.

The vernier acuity examining soft wear system was developed to detect the 14 cases (14 eyes) with vitreous opacity patients preoperatively. Two fixed targets and a movable target are shown on the computer screen. The examine was asked to adjust the position of the central target and the relationship between it and align them by using a track-ball. The computer automatically recorded the deviations of distances between the movable target and the specific one, and computed the average threshold of hyperacuity and its variance. Then the hyperacuity result and postoperative visual acuity were compared.

Paired t-test showed that the difference between peroperative and postoperative vernier acuity thresholds was not significant (t = 0. 52, P = 0. 612). The coefficient of correlation was 0. 85 (P < 0. 01). Neither was the threshold variance (t = 0. 431, P = 0. 674). The correlation coefficient was 0.97 (P < 0.01). The correlation coefficient between preoperative hyperacuity threshold and postoperative visual acuity was -0.74 (P < 0.01), and that between preoperative threshold variance and postoperative visual acuity was -0.95 (P < 0.01). Based on the preoperative vernier acuity threshold and its variance, the function of linear regression was Y = 0.943 - 0.000116THv - 0.00193SDv.

Vernier acuity remains good consistency after vitrectomy, and it is one of the sensitive parameter in predicting the postoperative visual function for vitreous opacities.