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Age-related changes in the anterior segment biometry during accommodation.
Yilei Shao1, Aizhu Tao1, Hong Jiang2
1Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States 2School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, China.
Investigative Ophthalmology & Visual Science
|June 2, 2015
Summary
Aging eyes show slower lens reshaping during accommodation, requiring more ciliary muscle effort. This study reveals age-related changes in dynamic accommodative responses using synchronized SD-OCT.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Human Physiology
Background:
- Human accommodation is crucial for clear vision at varying distances.
- Age-related changes can impair the accommodative system, affecting visual function.
- Understanding these dynamics is key to addressing presbyopia and related conditions.
Purpose of the Study:
- To investigate the age-related dynamic response of human accommodative elements.
- To quantify changes in lens thickness, anterior lens curvature, and ciliary muscle parameters during accommodation.
- To compare the dynamic responses between younger and older individuals.
Main Methods:
- Utilized synchronized spectral domain optical coherence tomography (SD-OCT) devices.
- Measured anterior segment parameters including lens thickness (LT), lens anterior curvature (LAC), ciliary muscle thickness (CMTMAX), and ciliary muscle anterior length (CMAL).
- Analyzed dynamic changes using a first-order exponential equation in 33 healthy subjects (20-39 years).
Main Results:
- Lens reshaping (LT and LAC) amplitude and peak velocity significantly decreased with age.
- Ciliary muscle parameters remained largely unchanged, except for CMAL peak velocity.
- The lag in lens reshaping compared to ciliary muscle contraction increased with age.
Conclusions:
- Significant age-related differences exist in the dynamic response of the human accommodative system.
- Lens reshaping becomes slower and less efficient with age.
- The ciliary muscle must contract more to achieve adequate accommodation in older individuals, indicating a reduced accommodative amplitude and increased accommodative lag.
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