Objective parameters of accommodation in concomitant strabismus

Abstract

To develop an objective method of determining binocular accommodative response (AR) and concomitant accommodation in patients with strabismus. The study included 34 patients (68 eyes) with concomitant horizontal strabismus aged 6 to 32 years. The parameters of accommodation were measured using open field Binocular Auto Ref/Keratometer Grand Seiko WR-5100K (Grand Seiko Co. Ltd., Japan). The prism was placed in front of the deviated eye or the prisms were distributed evenly in front of both eyes until the deviation was eliminated. The addition of prisms had no effect on the refractometry results. In convergent strabismus monocular, binocular, direct and consensual accommodation responses were significantly higher than in divergent: -2.15±0.1 D and -1.66±0.12 D; -2.13±0.09 D and -1.33±0.14 D; -2,04±0,15 D and -1,16±0,1 D; -1.97±0.15 D and -1.06±0.09 D, respectively. In divergent strabismus and myopia, the binocular response was 2.8 times higher than in hyperopia (-1.8±0.09 D and -0.63±0.04 D, respectively). Resting tonus of accommodation (RTA) value was higher in patients with hyperopia, both with convergent (mean -2.27±0.41 D) and divergent strabismus (-2.36±0.47 D). Minimal RTA was observed in patients with convergent strabismus and myopia (mean -0.75±0.1 D). The study resulted in the development of a method of objective accommodometry of strabismic patients with deviation eliminated by prisms. Monocular and binocular AR were significantly higher in convergent strabismus compared to divergent, where consensual accommodation of the squinting eye is significantly reduced compared to the paired one. In patients with consensual strabismus, RTA is significantly higher in hyperopia than in myopia regardless of the form of strabismus.