Evaluation of corneal flap dimensions and cut quality using a manually guided microkeratome

BACKGROUND: To evaluate reproducibility of corneal flap dimensions and cut quality with repeated blade use with a manually guided microkeratome in pig eyes. METHODS: Corneal flaps were created using a manually guided microkeratome ( Model One, Moria) with an intended 130-mu m cut depth in 130 enucleated pig eyes. Flap thickness was calculated by pachymetry and diameter was estimat ed by means of applanation lenses compared to planimetry. Histology and sca nning electron microscopy of samples and blades were performed to evaluate the keratectomy surface and blade cutting edge after repeated use of the bl ades. RESULTS: Mean flap central thickness was 135 mu m (SD, 37 mu m). The mean d iameter of 8.4 mm (SD, 0.4 mm) correlated significantly (P<.001) to the int ended diameter (r=.79). Mean difference from the intended diameter was 0.8 mm (SD, 0.3 mm; range, 0.04 to 1.4 mm). Scanning electron microscopy showed even and smooth cuts with chatter lines at the keratectomy edge using new blades. After repeated blade use, increasing cut irregularity, folds, and t issue remnants on the corneal bed surface, and nicks and tissue remnants at the cutting edge of the blades were observed. CONCLUSION: Reproducible flap dimensions were obtained using the Moria One microkeratome on pig eyes. The cut surface was regular and smooth with a ne w blade, but surface quality deteriorated considerably after repeated use o f the same blade.