Stereovision in patients with intermittent exotropia before and after surgical treatment

PurposeTo determine the effect of the initial stereovision on the outcome of intermittent exotropia surgical treatment.Methods20 patients with intermittent exotropia aged 10–21 years with visual acuity with correction 0.88 ± 0.29 who received surgical treatment were observed. Angle of deviation before surgery was 6–25 degrees, in average 15.7 ± 1.3 deg. for fare distance and near in average of 8.2 ± 2.18 deg, vertical component 0–3 degrees was observed in 65% of patients who underwent surgical treatment in accordance with generally accepted surgery tactic ‐ recessions and resections of extraocular muscles (Avetisov E. S.,1977, Von Noorden, E. Campos, 2002). Before and after treatment conventional ophthalmic examination and stereoacuity were determined using the Test Lung 2 in all patients.ResultsAs a result of treatment the angle of exotropia decreased in all patients and was in average 3.9 ± 1.9 deg for distance and 3.5 ± 1.4 deg for near, binocular vision was restored in 70% (14) of patients. Before treatment, only in 25% (5) of patients showed stereoacuity for near (200–600 arc sec) and 75% (11) did not show stereovision. After treatment, the stereoacuity for near increased and was detected in 65% of cases (13), compared to 5 that were before treatment (χ2 = 6.4, p = 0.01). Alignment of eyes and best stereoacuity (200–400 arc sec) was found after treatment and appeared in individuals who showed stereoacuity for near 200 arc sec before surgery and the nearest point of convergence less than 6 cm.ConclusionsPreliminary data suggest that in patients with intermittent form of exophoria good stereoacuity for near is a favorable factor for the prediction of treatment. In patients with orthotropic position of eyes stereoacuity after surgical treatment increased in 65% of cases.