A study led by Sunwoo Kwon, PhD, while a postdoc in the Levi lab, with co-authors Drs. Julien Belen, Artashes Yeritsyan, and Dennis Levi, was published in the Optometry and Vision Science Journal of the American Academy of Optometry. The paper is titled, “Reduced visual acuity disrupts fixational stability but fails to fully capture amblyopic eye movements.”
Key Takeaways
Blurring the vision of healthy adults with convex lenses to reduce their visual acuity makes their eyes less steady during fixation — mainly by increasing slow drifting eye movements. However, it does not recreate the full range of abnormal tiny eye movements seen in amblyopia (commonly known as “lazy eye”), particularly the larger corrective jumps called microsaccades. Importantly, these destabilizing effects only appeared when viewing with one eye; under binocular (both eyes open) conditions, the instability largely disappeared in healthy observers, and fixational stability markedly improved even in people with amblyopia.
These results show that while reduced visual acuity alone contributes to shaky fixation, the more severe oculomotor problems in amblyopia arise from additional changes in brain development that affect higher-order circuits coordinating eye movements. Our findings reveal that amblyopia is more than just poor eyesight — it involves deeper disruptions in brain wiring beyond the primary visual cortex (V1) — while also highlighting the powerful stabilizing role of binocular vision, which can help compensate for unequal acuity between the eyes.
Read the Paper