To observe and discuss the efficacy of vision training for patients with small-angle exo deviation after surgery for intermittent exotropia.

Patients from the Eye Hospital of Wenzhou Medical University who presented with small-angle exo deviation (≤25 PD at distance and ≤35 PD at near by objective examination) after surgery for intermittent exotropia were randomly recruited for a prospective study. Forty patients who volunteered to undergo vision training at the hospital for about 2~3 times a week for 3 months were assigned to the treatment group. Forty patients who were prescribed eyeglasses only served as the control group. All patients were aged 7-14 years, had normal vision and eye disease was ruled out. The oculomotor parameters were assessed by the same doctor before the study and 3 months after the study. Testing parameters included accommodation, magnitude of deviation, vergence, stereopsis, and the Newcastle Control Score (NCS). All data were statistically analyzed by a t test or χ² test. The criteria for cure in the experiment: no daily manifest deviation, good fusion function and stereovision at distance and near.

There was no difference in the magnitude of the exo deviation between the treatment and control group before surgery or after surgery, the magnitude of the exo deviations at distance and near, the fusion function, the stereoacuity test results, NCS, or the proportion with myopia (P>0.05). The results for the treatment group after the experiment were significantly better than the results for the control group for the magnitude of the exo deviations at distance (t=-2.74, P<0.05) and at near (t=-3.00, P<0.05) using objective testing methods, and the magnitude of the exo deviation at distance (t=-3.33, P<0.05) and at near (t=-4.25, P<0.05) using subjective testing methods. The differences in convergence at distance (t=5.81, P<0.05) and at near (t=7.01, P<0.05), stereoacuity examination [χ²= 21.59, 19.95, 34.94, P<0.05], nearpoint of convergence (t=-6.40, P<0.05), NCS (t=-6.40, P<0.05), and the cure rate (χ²=16.67, P<0.05), were statistically significant. After the experimental period, there was a significant difference for the treatment group in the magnitude of the exo deviation at distance using objective testing (P<0.05), while other oculomotor parameters improved (P<0.05). Patients in the treatment group whose magnitude of exo deviation was ≤20 PD had a better improvement rate than patients with >20 PD (χ²=4.55, P<0.05); patients with an NCS of <3 had a better improvement rate than patients whose NCS was ≥3 (χ²=4.91, P<0.05).

Vision training can effectively promote the contol of daily eye position, improve convergence, and have a beneficial effect on stereovision. Vision training is meaningful for patients with a magnitude of exo deviation ≤20 PD after surgery for intermittent exotropia.

Vision trainning; Binocular vision; Operation; Intermittent exotropia