Premium
The shape of the corneal apical zone after excimer photorefractive keratectomy
Author(s) -
Patel S.,
Marshall J.,
Fitzke F. W.,
Gartry D. S.
Publication year - 1994
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1994.tb07184.x
Subject(s) - photorefractive keratectomy , cornea , excimer , ophthalmology , excimer laser , corneal topography , refractive surgery , refractive error , medicine , optics , eye disease , laser , physics
Applying an experimental photo‐keratoscope, which assesses the shape of cornea within the pupillary region, to a group of subjects who have undergone excimer laser photorefractive keratectomy over a central 4 mm chord diameter of the cornea, we report the shape of the typical cornea within the ablated zone conforms to a steepening ellipse (average shape factor, 1.25). A statistically significant difference in the mean shape factor (asphericity) between the photoablated and the normal cornea (average shape factor 0.89) was not confirmed. However, there is more variability in the shape factors found in the photorefractive keratectomy group compared with normals, within the same distance from the corneal apex. Using the criterion of overlap within two standard deviations, averaging the vertical horizontal meridians, 75% of photorefractive keratectomy eyes fall within the shape factor limits of the normal eye group. In all cases the post‐ablated corneal surface was found to be regular in terms of surface quality alone. The excimer photorefractive keratectomy technique is therefore a clinically acceptable method of refractive surgery.