Effect of surgery on longstanding strabismus on binocular visual evoked potential]

To analyse the effect of surgery on binocular visual evoked potential (BVEP) in adults with longstanding strabismus.A prospective study was performed on 40 patients with a history of longstanding strabismus. Visual evoked potentials to binocular and monocular pattern reversal stimulation were recorded before surgery and 3 months after surgery. Binocular visual function was analysed by Worth and TNO tests before and after surgery.We did not find any differences between deviation and BVEP postoperatively (P = 0.82). The mean of BVEP and the percentage of increment of the BVEP response (10.5 and 27.14%) were larger postoperatively, than preoperatively (9.87 and 16.6%), P = 0.32 and P = 0.17, respectively. There were differences in the TNO results after surgery (P = 0.03) and when compared with postoperative deviation (P = 0.02), but not between TNO and BVEP postoperatively (P = 0.29). There were differences in the Worth results after surgery, and comparing with deviation and BVEP (P = 0.00, P = 0.01 and P = 0.07).Surgery in adults with longstanding strabismus could improve the deviation and seemed to improve BVEP response, but this point could not be confirmed. The results are not enough to show that the BVEP would be an objective test for binocular function evaluation, although there could be a relationship between BVEP and the TNO response.