Accommodative responses to anisoaccommodative targets

Abstract

Young subjects (mean age 25.2 +/- 2.3 years) viewed with symmetric convergence two fusible targets situated at different distances (i.e. anisoaccommodative targets). The fused target was a Maltese cross which subtended 3 degrees at the eye: the right and left arms of the cross were seen by both eyes and each of the other arms was seen by only one eye. The vergences of the anisoaccommodative targets differed by either 3.00 or 0.50 D. Accommodation of each eye was measured by a Canon R1 auto-refractor. There was no evidence of systematic anisoaccommodation. When presented with anisoaccommodative targets, the accommodation of both eyes tended towards a level which was more appropriate to the farther target, i.e. that which required less accommodative effort. Implications of the findings for optometry are briefly discussed.