Abstract
Purpose :
Previously, eccentric fixation was reported in children with residual amblyopia who had an interocular difference [IOD] of visual acuity ≥0.2 logMAR after treatment (glasses, patching, atropine). Using OCT, we measured eccentric fixation (called OCT fixation shift) in children with residual amblyopia (Jin et al, 2020). We found that OCT fixation shift is significantly higher in amblyopic eyes than in fellow eyes and control eyes, especially in children with strabismic amblyopia where 78% of had measurable OCT eccentric fixation. We ask how common OCT fixation shift is present in children without residual strabismic amblyopia (IOD of visual acuity improved to <0.2 logMAR with treatments). Here, we report OCT fixation shift in strabismic amblyopic children without residual amblyopia and compare it with those with residual amblyopia.
Methods :
Children aged 4 to 16 years (mean±SD = 9.7±3.3 years) with non-residual strabismic amblyopia (n=23), with residual strabismic amblyopia (n=28), and normal controls (n=75) were studied. Spectral-domain OCT was used to estimate fixation shift. We asked the child to focus on the internal blue dot fixation target of the OCT. OCT fixation shift, i.e. the distance between the foveal center and the fixation point, was measured, adjusted for axial length, and converted into visual degrees. OCT fixation shifts in the amblyopic eye in two amblyopic groups and the right eye of the control group were compared by ANOVA.
Results :
OCT fixation shift was 0.17±0.29° for control eyes, 1.54±1.48° for residual amblyopic eyes, and 0.43 ± 0.44° for non-residual amblyopic eyes (F=34.2, P<0.001). Fixation shift between the non-residual amblyopic group and control group did not differ (P=0.31), and fixation shift for the non-residual amblyopic group was significantly lower than the residual amblyopic eyes (P<0.001). Fifteen (65%) in the non-residual group had the measurable fixation shift, which is not significantly different from that (78%) in the residual group (chi-squared=0.56, p=0.45).
Conclusions :
Eccentric fixation, assessed by OCT fixation shift, is measurable in about 2/3 of children with strabismic amblyopia (both residual and non-residual). Although the occurrence of OCT fixation shift shows similar frequency in both groups, the magnitude of OCT fixation shift is less in children without residual strabismic amblyopia than those with residual strabismic amblyopia.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.