Ciliary muscle function and accommodation in myopia

Myopia (short-sightedness) is a progressive condition often associated with near work. This research investigated the accommodation system during treatment with myopia-control multifocal spectacles. Meta-analysis of prior work showed that effectiveness of multifocal spectacles reduces with time, even after the first six months. During accommodation, the anterior ciliary muscle thickens, and its overall length reduces, in both emmetropes and myopes. Myopes have the larger lags of accommodation. Multifocal spectacles initially decrease the lags, but over-time the lags increase, and upgrading addition power by 0.50D restores the initial effect. Modifications to add power can sustain the treatment effect for longer periods.