The effect of refractive error on the accommodative response gradient.

The accommodative responses of early-onset myopes, late-onset myopes, emmetropes and hyperopes were measured over a range of 5 dioptres using an objective infra-red autorefractor. Differences were found between the four refractive groups, with hyperopes accommodating more for near targets than emmetropes, followed by early-onset myopes then late-onset myopes. Moreover a strong correlation between the accommodative response gradient and refractive error was found, suggesting that hyperopes accommodate more to a particular target than do emmetropes or myopes. The results are interpreted in the context of a dual innervation to the ciliary muscle.