Symmetric or asymmetric surgery for basic intermittent exotropia

Surgical results after symmetrical and asymmetrical surgery performed by the same surgeon (M.S.) as initial procedure for basic intermittent exotropia were retrospectively analysed in 55 young patients. Twenty-five patients underwent unilateral recess-resect surgery on the non-fixating eye (Groupe 1) and 30 patients bilateral lateral rectus recessions (Group 2). The average age at surgery was 6.5 yrs (range: 2-18). The average post-operative follow-up was 2.81 yrs (range: 0.50-8 yrs), (p = 0.143). Sensory fusion was assessed by the Bagolini straited glasses and/or the Worth test and stereopsis by either the TNO and/or Lang stereoacuity test prior and after surgery. Prior to surgery, 84% of the patients had reached isoacuity. Ocular motility was normal in all patients. The average size of preoperative exotropia measured by prism and alternate cover test was 28 PD (SD = 5) for both Groups. In the immediate postoperative period, 53% of the patients were overcorrected without any statistically significant difference between the 2 groups (p = 0.053). Nine (16%) patients had a "mixed" deviation (from eso- to exo depending of the fixation distance), 8 (15%) patients were orthophoric (20% in Group 1 vs 10% in Group 2) and 9 (16%) patients were undercorrected (12% in Group 1 vs 20% in Group 2). The results at last exam, were similar between the 2 Groups; good or fair alignment was achieved in 29 (53%) patients (p = 0.512); 23 (42%) patients had still X(T) (p = 0.829) and 3 (5%) patients were overcorrected. We concluded that even if the immediate postoperative results seem better with asymmetrical surgery, in the long-term there is no significant difference between the two surgical procedures.