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Meridional variations of corneal shape
American Journal of Optometry and Physiological Optics
|October 1, 1984
Summary
Corneal shape analysis revealed an ellipsoidal form in most eyes. Corneal curvature varied by meridian and age, reducing astigmatism, while asphericity remained consistent.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Optometry
Background:
- Understanding corneal shape is crucial for refractive error correction.
- Photokeratoscopy provides detailed corneal topography data.
- Conicoid models are used to describe corneal geometry.
Purpose of the Study:
- To analyze the geometric properties of the cornea using photokeratoscopy.
- To determine the typical conicoid shape of the human cornea.
- To investigate age-related changes in corneal curvature and asphericity.
Main Methods:
- Photokeratoscopy was used to capture corneal surface data from 196 eyes.
- A conicoid equation was fitted to four individual corneal meridians for each eye.
- Statistical analysis was performed to assess variations in curvature and asphericity.
Main Results:
- The corneal shape was predominantly ellipsoidal across all meridians.
- Corneal radius of curvature varied significantly between meridians.
- Corneal astigmatism decreased with age due to changes in radii of curvature, while asphericity remained stable.
Conclusions:
- The human cornea generally follows an ellipsoidal shape.
- Age-related changes in corneal curvature influence astigmatism.
- Corneal asphericity is largely independent of age and meridian.