Decompensation of distance exotropia reduces accommodation

Decompensation of distance exotropia reduces accommodation, meaning it must be prevented in near vision, reveals a study in the British Journal of Ophthalmology.

The investigation, led by Dr Anna Horwood, School of Psychology & Clinical Language Sciences, University of Reading, Reading, UK, consisted of 19 participants with distance exotropia. Each patient was tested using the PlusoptiXSO4 photo refractor set in a remote haploscopic device.

The refractor recorded simultaneous vergence and accommodation of a range of targets demonstrating the various combinations of blur, disparity and proximal cues. The assessments were made at four fixation distances between 2 m and 33 cm.

The study discovered that manifest exotropia was more common in the more impoverished cue conditions. The mean accommodation increase for the all-cure target was considerably reduced. The mean under-accommodation was 2.33 D at 33 cm. Blur and proximity drove residual responses when the profile of near cues usage changed after decompensation.