Optic Coherence Tomography for Accommodation Control in Children with Hyperopic Anisometropia and Amblyopia

The aim is to evaluate the ocular accommodation system in hyperopic anisometropia and amblyopia in children after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and in children with spectacle correction using optical coherence tomography (OCT).

The present study included children with hyperopia and anisometropia of more than 3 D, high and medium degree of amblyopia. Patients were divided into two groups: group 1 consisted of 30 children after FS-LASIK, group 2 was comprised of 30 children with spectacle correction. The temporal part of the ciliary muscle was assessed using the CASIA2 optical coherence tomography system (Tomey, Japan). The study was carried out with a narrow pupil fixing the gaze on the target at a distance of 33 cm and under cycloplegic conditions. The ciliary muscle thickness (CMT) was analyzed at four different levels: the maximum thickness of the ciliary muscle (CMT_max), and at a distance of 1, 2, and 3 mm from the scleral spur (CMT₁, CMT₂, and CMT₃, respectively). The fluctuation amplitude in the thickness of the ciliary muscle (ΔCMT), i.e. the ratio of indicators with a narrow and wide pupil, was also evaluated.

The ciliary muscle thickness of the amblyopic eye in group 1 was 808±38 μm for CMT_max, 724±54 μm for CMT₁, 446±44 μm for CMT₂, and 223±37 μm for CMT₃, these indicators in group 2 were 812±33, 735±33, 432±35, and 229±29 μm, respectively.Children of group 1 have been found to have an increase in ΔCMT of the amblyopic eye. The value of ACMT_max increased from 21±6 to 30±4 μm, ACMT₁ from 19±6 to 29±5 μm, ACMT₂ from 12±4 to 16±4 μm, ACMT₃ from 11±4 to 16±4 μm, which is associated with an increase in visual acuity and a decrease in the refractive component. All changes within the group were statistically significant (p<0.01).

OCT is a fairly informative method for studying the accommodative structures of the eye in children, providing the opportunity to objectively assess the amplitude of fluctuations in the thickness of the ciliary muscle during the treatment. It has been established that after refraction operation, the work of the ciliary muscle of the amblyopic eye was significantly improved, which is reflected in the increased values of ΔCMT, CMT₂, and CMT₃ and brings these parameters closer to those of the better paired leading eye.