Emmetropes and myopes differ little in their accommodation dynamics but strongly in their ciliary muscle morphology.

Emmetropes and myopes differ little in their accommodation dynamics but strongly in their ciliary muscle morphology. Vision Res. 2019 Aug 08;: Authors: Wagner S, Zrenner E, Strasser T Abstract Previous work suggested an association between near vision and myopia. We therefore investigated the accommodation process in emmetropes and myopes regarding morphologic changes of the ciliary muscle (CM) and power changes of the lens for different accommodation demands. The temporal CM of 18 emmetropic and 20 myopic students was imaged via anterior segment optical coherence tomography during far and near accommodation (2.5D, 3D, 4D). Additionally, accommodation dynamics to the stimuli pattern far-near-far (15s each; 2.5D, 3D, 4D) were recorded with eccentric infrared photorefraction. OCT images were processed using custom-developed software facilitating the analysis of selective CM thickness (CMT) readings and CMT profiles. Anterior CMT readings were significantly smaller in myopes. Starting at 1.4mm posterior to the scleral spur (SP), myopic CM became thicker than emmetropic. Anterior CMT changes (ΔCMT) continuously increased with accommodation demand in myopes while emmetropic ΔCMT only increased from 2.5D to 3D. Compared to emmetropes, myopes showed smaller ΔCMT but increased CM movement relative to SP. There were no significant differences between the groups for accommodation changes from far to near vision and vice versa, velocity, mic...
Source: Vision Research - Category: Opthalmology Authors: Tags: Vision Res Source Type: research