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Simulating the Mechanics of Lens Accommodation via a Manual Lens Stretcher
Published on: February 23, 2018
Volume change of the ocular lens during accommodation
R Gerometta1, A C Zamudio, D P Escobar
1Dept of Ophthalmology, Mount Sinai School of Medicine, One Gustave L Levy Place, New York, NY 10029, USA.
American Journal of Physiology. Cell Physiology
|June 1, 2007
Summary
Mammalian lens accommodation involves shape changes, potentially including volume reduction due to fluid movement. Impeded fluid flow in aging lenses may cause loss of focusing ability.
Area of Science:
- Ophthalmology
- Biophysics
- Physiology
Background:
- Mammalian lens accommodation involves shape changes for focusing.
- The lens must alter its volume, surface area, or both during accommodation.
- Lens topology resembles a torus, enabling volume calculation from cross-sectional area (CSA).
Purpose of the Study:
- To determine if lens volume changes during accommodation.
- To investigate the role of fluid movement in lens shape changes.
- To explore potential causes of age-related accommodative loss.
Main Methods:
- Developed an approach to determine lens volume from CSA using photographic analysis.
- Utilized a custom stretching device to simulate accommodation in isolated bovine lenses (ciliary body-zonulae-lens complex).
- Measured CSA and center of mass to calculate lens volume under simulated accommodation.
Main Results:
- Mechanical stretching decreased lens anterior-posterior length, CSA, and volume.
- Lens volume and CSA recovered in aqueous solution but not in oil, suggesting fluid movement.
- Theoretical models indicated volume changes during human lens accommodation.
Conclusions:
- Lens accommodation may involve significant changes in lens volume, not just surface area.
- Fluid movement into and out of the lens is likely crucial for accommodation.
- Impaired fluid flow in aging lenses could lead to reduced accommodative power.
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