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Published on: May 3, 2016
Changes in lens dimensions and refractive index with age and accommodation
Catherine E Jones1, David A Atchison, James M Pope
1School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, Australia.
Summary
Human eye lens thickness increases with age, while diameter and refractive index remain stable. Accommodation alters lens thickness and diameter but not significantly its refractive index.
Area of Science:
- Ophthalmology
- Biomedical Optics
- Human Physiology
Background:
- The human eye lens changes shape to focus light, a process known as accommodation.
- Understanding age-related changes in lens dimensions and optical properties is crucial for vision science.
Purpose of the Study:
- To quantify age-related changes in human eye lens dimensions and refractive index.
- To assess the impact of accommodation on lens geometry and refractive index.
Main Methods:
- Magnetic Resonance Imaging (MRI) was employed to map refractive index and measure lens geometry (thickness, diameter).
- 44 volunteers (18-59 years) were studied in an unaccommodated state (0.17 D stimulus).
- A subset of younger volunteers (18-33 years) underwent measurements during accommodation (6.67 D stimulus).
Main Results:
- Lens thickness significantly increased with age in the unaccommodated state.
- Lens diameter and central refractive index showed no significant age-related changes.
- Accommodation led to increased lens thickness and decreased diameter, with no statistically significant change in central refractive index.
Conclusions:
- The observed changes in lens dimensions during accommodation support the Helmholtz theory.
- Age primarily affects lens thickness, while accommodation involves dynamic shape changes.
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