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Prolonged nearwork affects the ciliary muscle morphology.
Sandra Wagner1, Frank Schaeffel2, Eberhart Zrenner3
1Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany.
Experimental Eye Research
|July 24, 2019
Summary
Prolonged near work thinned the ciliary muscle (CM), contrary to expectations for striated muscles. This study found increased accommodative response after near work, suggesting a potential link to myopia progression.
Area of Science:
- Ophthalmology
- Physiology
- Vision Science
Background:
- Near work is a suspected factor in myopia development.
- The ciliary muscle (CM) plays a crucial role in visual accommodation.
- Understanding CM changes during near work is vital for myopia research.
Purpose of the Study:
- To investigate the impact of prolonged near work on ciliary muscle (CM) morphology and accommodation.
- To compare these effects in myopic and emmetropic young adults.
Main Methods:
- Optical coherence tomography (OCT) was used to image CM thickness during distance and near vision.
- Eccentric infrared photorefraction assessed accommodation response before and after a 30-minute reading task.
- Custom semi-automatic segmentation analyzed OCT images for CM thickness profiles.
Main Results:
- The ciliary muscle (CM) showed significant thinning after prolonged near work in both myopic and emmetropic subjects.
- Accommodation response for distant targets increased significantly post-near work, with a greater myopic shift observed in myopes.
- No significant change in the velocity of accommodation was detected.
Conclusions:
- Contrary to hypotheses of ciliary muscle spasm, near work induced CM thinning.
- The observed increase in accommodative response after near work may contribute to myopia progression.
- Further research into sympathetic innervation's role in near work-induced ocular changes is warranted.
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