Relative scotomata in the "normal" eye of functionally amblyopic patients. A scanning laser ophthalmoscope (SLO) micreperimetric study.

Abstract

Purpose: To evaluate amblyopic patients with scanning laser ophthalmoscope (SLO) microperimetry to determine whether SLO assessment and data might provide useful information in our understanding of amblyopia and determine its utility in the evaluation of amblyopic patients.

Methods: In this retrospective case series, selected for SLO testing case series, clinical data of forty-six patients with amblyopia were reviewed after completion of treatment for anisometropic or strabismic amblyopia. Ten ophthalmologically age-matched, normal patients served as controls. All patients were tested with the SLO, evaluating for the presence of macular scotomata. SLO findings were assessed within each group and between groups.

Results: A macular scotoma was found in the amblyopic eye of 25 of 26 anisometropic amblyopic patients and all 20 strabismic amblyopia patients. Twenty of 26 patients with anisometropic amblyopia had a relative scotoma in the non-amblyopic "normal" eye. All 20 patients with strabismic amblyopia also had a non-amblyopic "normal" contralateral eye scotoma. None of the normal control patients had a scotoma in either eye. Several ocular and binocular clinical features were correlated to scotoma findings within and between groups.

Conclusion: The SLO proved useful for the assessment of some features of amblyopia. A scotoma was identified not only in the amblyopic eye of all but one amblyopic patient, as expected, but also in almost all of the fellow non- amblyopic, presumed "normal" contralateral eyes, and in spite of treatment normalization of visual acuity and stereoacuity in several cases. Thus, the ocular and binocular pathological effects of unilaterally functional amblyopia are not limited to the amblyopic eye but may also be seen, to a sub-clinical degree, by SLO microperimetry in the supposedly normal contralateral eye as well as in the apparently successfully treated previously amblyopic eye.