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Determination of corneal gel dynamics
T Matsuura1, S Gorti, T Tanaka
1Department of Physics, Massachusetts Institute of Technology, Cambridge 02139, USA.
European Biophysics Journal : EBJ
|July 22, 1999
Summary
Corneal light scattering reveals distinct diffusion coefficients, suggesting lamellar layers act as gel sheets. Changes in temperature or pressure induce reversible phase transitions, impacting light scattering and diffusion dynamics.
Area of Science:
- Biophysics
- Corneal Physiology
Background:
- The cornea's structural and dynamic properties are crucial for vision.
- Understanding corneal tissue mechanics at a molecular level is essential.
Purpose of the Study:
- To investigate the diffusion dynamics within the cornea using light scattering.
- To explore the relationship between corneal structure, diffusion, and response to external stimuli.
Main Methods:
- Dynamic light scattering (DLS) to measure diffusion coefficients.
- Analysis of intensity autocorrelation functions.
- Corneal swelling kinetics measurements.
- Varying temperature and pressure (stretching) to observe dynamic changes.
Main Results:
- Two independent diffusion coefficients were identified: D (fast) = 2.4 x 10(-7) cm2/s and D (slow) = 9.4 x 10(-9) cm2/s.
- Diffusion coefficients were largely independent of sampling location but differed within cross-sections.
- Light scattering results contrasted with swelling kinetics, suggesting gel-like behavior of lamellar layers.
- External stimuli (temperature, pressure) caused reversible changes, indicating a phase transition around 50°C or 16% stretching.
Conclusions:
- Corneal lamellar layers may function as independent gel sheets.
- Observed divergent behaviors in scattering and diffusion under stress are characteristic of a phase transition.
- The cornea exhibits reversible phase transition properties under specific thermal or mechanical stress.