Children with amblyopia demonstrate an increased inaccuracy of sustained and post-saccadic fixations compared with children who have recovered from amblyopia or who never had the disorder, according to a study published in BMC Ophthalmology. Children who have recovered from amblyopia appear to have restored eye movement functions, according to the report.
Researchers enrolled 135 children in the analysis consisting of participants with amblyopia (n=45; 51% girls; mean age, 6.67 years), children who recovered from amblyopia (n=45; 51% girls; mean age, 7.56 years) and control individuals (n=45; 62% girls; mean age, 7.40 years). Patients with amblyopia underwent treatment for less than 1 year and had a best-corrected visual acuity (BCVA) of 20/30 or worse in the worse eye or an interocular difference in BCVA of two lines or more (≥0.2 logMAR). Participants who recovered from amblyopia had a history of amblyopia with resolved visual acuity at the most recent visit after treatment. Control individuals had normal or corrected-to-normal visual acuity in both eyes and a stereoacuity of 60 arc seconds or more.
All participants underwent comprehensive ophthalmic examinations consisting of visual acuity measurement, cover test, and biomicroscopy. Deviations in gaze position were measured and recorded with a remote eye tracker as participants focused on a target located 80 cm away. Main outcome measures included horizontal and vertical deviations in fixation (horizontal: Fix-X; vertical: Fix-Y) and saccadic (horizontal: Sac-X; vertical: Sac-Y) movements, which were compared among the 3 cohorts.
According to the report, Fix-X, Fix-Y, Sac-X, and Sac-Y were significantly larger among patients with amblyopia compared with participants in the remaining 2 cohorts, indicating increased inaccuracy of both sustained and post-saccadic fixations in amblyopia. There were no differences in fixational or saccadic deviations between children who recovered from amblyopia and control group participants, indicating that these eye movement functions appeared to be restored in children who recovered from the disorder.
“Early and efficient intervention for amblyopia could additionally restore eye movement functions since there was no significant difference in fixation deviations between children with recovered amblyopia and normal subjects,” according to the researchers. “Quantitative assessment of eye movements might serve as an additional indicator of the efficacy of amblyopia treatment in clinical practice.”
Study limitations include a single center design, ethnic homogeneity which limited participation from several ethnic groups, and exclusion of patients with marked strabismus.
Zhou Y, Bian H, Yu X, Wen W, Zhao C. Quantitative assessment of eye movements using a binocular paradigm: comparison among amblyopic, recovered amblyopic and normal children. BMC Ophthalmol. Published online September 9, 2022. doi:10.1186/s12886-022-02579-5