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Contact lens base curve prediction from videokeratography
J S Chan1, R B Mandell, L Johnson
1Morton D. Sarver Laboratory for Contact Lens and Cornea Research, School of Optometry, University of California, Berkeley, USA.
Purpose:
To assess whether the contact lens to cornea-bearing relationship, as determined from the fluorescein pattern, can be predicted from videokeratography.
Methods:
Nineteen non-rigid gas permeable (RGP) lens wearers were each tested for fluorescein patterns with a series of seven RGP contact lenses of different base curves, and compared to a theoretical estimate of the fitting relationship from videokeratography. The experimentally determined alignment lens was then compared to the theoretical alignment (TA) value as determined from the central curvature and eccentricity.
Results:
The mean difference in lens choice between the TA and experimental alignment (EA) values was -0.01 +/- 0.04 mm and between the simulated keratometric (KA) readings and the EA choice was 0.11 +/- 0.05 mm.
Conclusion:
A knowledge of the eccentricity value from videokeratography allowed a better prediction of the base curve to cornea relationship than was provided by only a central corneal measurement.