AIM: To observe binocular vision improvement of different exotropia after marginal myotomy and to discuss the impact of different types of exotropia on the recovery of binocular vision after surgery.

METHODS: We selected 59 patients for case study and divided them into three groups by types of exotropia. Intermittent exotropia 27 cases is Group 1; Constant exotropia 21 cases is Group 2; V-pattern exotropia 11 cases is Group 3. We examined their three-degree visual functions via synoptophore preoperative and postoperative respectively. We recorded the examination data and conducted in-depth analysis after 6mo follow-up.

RESULTS: Comparison on binocular vision improvement of different types of exotropia. 1)Postoperative level Ⅰ simultaneous perception: at 1 mo postoperative, visual recovery in Group 1(22 cases, 81%)was better than that in Group 2(11 cases, 52%)and Group 3(5 cases, 46%). The difference was statistically significant(P<0.05); 2)Postoperative level Ⅱ fusion: at 1mo, 3mo and 6mo postoperative, there were significant differences in fusion function among the three groups(P<0.05). The recovery of fusion function in Group 1(20 cases, 74%)was better than that in Group 2(9 cases, 43%)and Group 3(4 cases, 36%)at 6mo. The fusion range of Group 1(17.15°±9.19°)was significantly larger than that of Group 2(9.00°±8.64°), and the difference was statistically significant(P=0.004); 3)Postoperative level Ⅲ distance stereoacuity: distance stereoacuity recovery of Group 1(9 cases, 33%)were again proved to be better than others. However, no statistical difference was found in the Ⅲ vision function between three groups(P>0.05); 4)Three-degree visual function had obvious improvement after marginal myotomy. The differences were statistically significant(P<0.001). The recovery was stable in 1mo postoperative.

CONCLUSION: Marginal myotomy can reduce intraoperative complications and traction of extraocular muscle, and improve surgical safety. There was significant improvement of three-degree visual function after marginal myotomy, and the recovery of binocular vision became stable 1mo postoperative. The binocular vision recovery of the intermittent exotropia patients was supreme to the constant exotropia patients and V-pattern exotropia patients. Constant exotropia and V-pattern exotropia had the same impact on the recovery of binocular vision. Thus, types of exotropia should be considered when deciding surgery timing, in order to achieve more effective recovery and to rebuild binocular vision.