Best way to measure accommodation

Defocus curve measurement of subjective amplitude of accommodation (AoA) is not affected by non-randomized letter sequences in presbyopic subjects, according to results of a study published in the August 2008 issue of the Journal of Cataract & Refractive Surgery.

Nayneet Gupta of the Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK and colleagues measured defocus curves (from +3.00 D to -3.00 D in 0.5 D increments) with various combinations of randomized and non-randomized letter sequences and/or lens presentation order in presbyopic subjects (n=20) to establish the most accurate way of calculating AoA in this manner. Objective and subjective AoA were measured.

The team observed that defocus curve measurements were not affected by which lens-presentation or letter sequence was used, although in combination the measurements obtained were less than desirable.

Thus the researchers concluded that, to measure subjective AoA by defocus curves, either non-randomized letter sequences or lens presentation could be used effectively.