Accommodation and fusion in patients with constant and intermittent exotropia

Abstract

PurposeTo determine the characteristics of the accommodation and fusion in patients with constant and intermittent divergent strabismusMethodsUnder observation there were 59 patients: 33 with a constant form of strabismus (I) and 26 with intermittent form (II) aged 10–21 y.o. with visual acuity with correction (0.8 ± 0.3) and refraction (0.5 ± 2.8) dptr, the angle of deviation in group I was for distance (36.6 ± 2.8) dptr, and for near (16.6 ± 2.5) dptr; in the II group (26.6 ± 2.8 and 12.0 ± 2.3) dptr respectively, p >0.05. The nearest point of convergence was determined by proximeter, the AK/A ratio by heterophory method and the fusion was assessed using synoptophore, distance and near deviations were assessed using prism cover test.ResultsData analysis showed that the nearest point of convergence did not differ significantly in patients of both groups (8.8 ± 0.9) cm and (8.6 ± 0.6) cm, respectively). Values of AK/A also did not differ significantly (−0.5 ± 2.5) and (1.02 ± 0.97), in the I and II group respectively, but values less than 0 were found in 53.5% of cases at the I and in 38% at the II. Fusion by synoptophore was significantly more frequently in patients of the II group – 53.8%, in comparison with the I – 24.4%, (χ2 = 6.2), p = 0.001.ConclusionsIt is noted that in cases with the permanent form of strabismus low values of AK/A are more common (53.5%) than in intermittent (38%), which may be associated with weakness of accommodative convergence in these patients. Found that the fusion exist significantly more common in patients with intermittent form of divergent strabismus (53.8%) in comparison with a constant (24.4%), χ2 = 6.2, p = 0.001.