Purpose: To determine whether the choice of instrumentation affects the quality and precision of corneal cuts during keratomileusis in situ.
Setting: Schlosspark-Klinik, Ophthalmology Department, Berlin, Germany.
Methods: The study was performed on 54 swine eyes and 3 human corneas using microkeratomes manufactured by Steinway, SCMD, and Eye Technology. The study results are based on micrometric and pachymetric measurements of actual slice thickness. Slice thickness and slice quality were evaluated using scanning electron microscopy. Three slices of defined thickness were made with each keratome.
Results: There was no significant difference in the degree of deviation of slice thickness from the intended value with any keratome. The micrometric measurement of the first lamella documented significantly less variation in the actual measurements achieved with the Eye Technology device (P < .01). All keratomes tested demonstrated a high degree of congruence between the intended values and those achieved in mean thickness and circularity of the cut. The Eye Technology device demonstrated the best profile and the cleanest margins, followed by the SCMD keratome, which caused minimal distortion of the stroma. The Steinway keratome has a high amplitude and produced 25 microns tears in the margins perpendicular to the plane of the cut.
Conclusion: There was no overall difference in cutting precision between the 3 tested keratomes. High-oscillation frequency of the blade resulted in a smooth cut.