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Holmium laser thermokeratoplasty
H Moreira1, M Campos, M R Sawusch
1Doheny Eye Institute, Los Angeles, CA 90033.
Ophthalmology
|May 1, 1993
Summary
Laser thermokeratoplasty uses a holmium: YAG laser to shrink corneal collagen, altering curvature. This study demonstrates controlled corneal steepening by heating stromal tissue.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Laser Surgery
Background:
- Corneal curvature influences visual acuity.
- Modifying corneal shape is a goal in refractive surgery.
Purpose of the Study:
- To investigate the efficacy of laser thermokeratoplasty in altering corneal curvature.
- To assess the relationship between ring diameter and induced corneal steepening.
Main Methods:
- Laser thermokeratoplasty was performed on 40 human cadaver eyes.
- A ring pattern of 32 spots (300 microns diameter) was used.
- Histologic examination and finite element modeling were employed.
Main Results:
- Increased ring diameter reduced induced corneal steepening.
- Central steepening ranged from 22.2 D (3 mm diameter) to 3.7 D (7 mm diameter).
- Histology revealed heat-induced stromal contraction up to 90% of stromal thickness.
Conclusions:
- Controlled heating of corneal stroma with a holmium:YAG laser can modify central corneal topography.
- These findings support previous research on laser thermokeratoplasty's potential.
- The procedure shows promise for controlled corneal reshaping.