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Central islands of corneal steepening after automated lamellar keratoplasty for myopia.

BACKGROUND
Central steep islands are a phenomena of videokeratography that demonstrate local central steepening within a larger diameter area of the cornea treated by refractive surgery that removed stromal tissue to reduce myopia. This report details four cases in which central steep islands occurred following automated lamellar keratoplasty (keratomileusis in situ).


METHODS
A total of 43 automated lamellar keratoplasty procedures were performed on 32 patients between January 1993 and September 1993. Central islands were identified using video-keratography.


RESULTS
Out of 43 cases of automated lamellar keratoplasty, central steep islands developed in six eyes of four patients. These steep areas developed within a few weeks after surgery; increases in the elevation of these islands correlated with recurring myopia. Slit-lamp microscopy revealed no epithelial surface abnormalities or difficulties with the interface of the resection. A central steep island did not prevent excellent uncorrected visual acuity. After subsequent refractive keratotomy for residual myopia, central steep islands either regressed or disappeared.


CONCLUSION
Central islands of corneal steepening may occur after automated lamellar keratoplasty for myopia. The etiology is unknown.