PURPOSE

Unilateral amblyopia is associated with inaccurate accommodation when viewing monocularly with the amblyopic eye, such as when performing traditional amblyopia therapies. This study investigated the repeatability of the accommodative responses over time to understand the likely pattern of defocus during these therapies.

METHODS

Children with (n = 17) and without (n = 18) unilateral amblyopia between 4 and 15 years of age completed two study visits within 1 week. During each visit, monocular distance and near visual acuity, near stereoacuity, Worth Four Dot testing and ocular alignment were assessed with the habitual optical correction, if worn. Monocular accommodative responses were evaluated three times, separated by 15-min intervals, using modified Nott dynamic retinoscopy while participants viewed broadband naturalistic images at 25, 33 and 50 cm.

RESULTS

Linear mixed models, with accommodative response and range of values as the dependent variables, showed that accommodative lags increased with stimulus demand, particularly for the amblyopic eyes with the worse visual acuity (p < 0.0001). The range of accommodative responses across repeated measures within a visit was typically less than 0.75 D and was consistent across visits (p > 0.17), with no main effect of visual acuity (p > 0.21).

CONCLUSION

These data suggest that the increased retinal defocus experienced by children with amblyopia during monocular viewing for amblyopia therapy is relatively stable. Whether this defocus impacts the success of amblyopia therapy remains an open question.