Abstract
Purpose :
Eccentric fixation is often associated with residual amblyopia, in which interocular difference of best corrected visual acuity is >=0.2logMAR even after glasses and patching. Eccentric fixation may be a contributing factor in strabismic amblyopia. In a pilot study, Nakamoto et al (2018) evaluated the utility of optical coherence tomography (OCT) in the quantification of eccentric fixation in 14 amblyopic children with both anisometropic and strabismic types of amblyopia. Here we evaluate eccentric fixation with OCT in a large cohort of children with residual amblyopia and explore the association of eccentric fixation with strabismus.
Methods :
Children with residual amblyopia (Amblyopic Group: N=56) and non-amblyopic children (Control Group: N=75) were enrolled. Age ranged from 4 to 17 years old. Amblyopia was associated with anisometropia (N=28), strabismus or both (N=28). Spectral-domain OCT was used to estimate fixation. Participants were asked to focus on the internal blue dot target of the OCT. OCT fixation shift, i.e. the distance between the fovea and the fixation point, was measured and adjusted with calculated axial length and converted into visual degrees. Fixation shift in the amblyopic eye, the fellow non-amblyopic eye, and the OD eye of the Control Group were compared using an ANOVA test with post-hoc paired comparisons. We also compared fixation shift between the anisometropic and strabismic amblyopia types.
Results :
The mean fixation shift was 0.17±0.29° for the control OD eyes; 0.94±1.24° for amblyopic eyes and 0.34±0.57° for fellow non-amblyopic eyes. There was significant difference in fixation shift among the control, amblyopic and the fellow eyes (F=17; P<0.001). According to Tukey multiple comparisons of means, the amblyopic eyes had significantly larger fixation shift than the fellow eyes (P<0.001); there was no significant difference between the fellow eyes and the control eyes (P=0.41). Fixation shift in the amblyopic eye was also significantly correlated with visual acuity (R=0.44, P<0.001). Fixation shift in the anisometropic amblyopic eye was significantly smaller than in the strabismic and/or the combined types (0.34±0.46° vs 1.54±1.48°, T =-4.00, P<0.001).
Conclusions :
OCT fixation shift can be used both in detection and quantification of eccentric fixation in children with residual amblyopia, especially in those with strabismus.
This is a 2020 ARVO Annual Meeting abstract.