Evaluation of corneal flap dimensions and cut quality using the Automated Corneal Shaper microkeratome

PURPOSE: To evaluate flap dimensions and cut deterioration with repeated bl ade use in an automated microkeratome. METHODS: The Automated Corneal Shaper (Chiron-Adatomed, Munich, Germany), 1 60-mu m plate attached, was used to make a corneal flap in 90 pig cadaver e yes, reusing blades up to five times. Flap diameter was measured by planime try and thickness was calculated by ultrasound pachymetry. Scanning electro n microscopy of stromal beds and blade cutting edges was performed to asses s cut deterioration after repeated blade use. RESULTS: Mean flap central thickness was 125 +/- 32 mu m. Mean vertical fla p diameter was 7.6 +/- 0.4 mm. No correlation was found between thickness a nd diameter (r = 0.15, P = .45). Progressive thinning of the flap was obser ved in the direction of the flap hinge. Smooth cuts (using new blades) with periodic chatter lines at the keratectomy edge and in the stromal bed were observed with scanning electron microscopy. Increasing tissue remnants on the stromal bed and decreasing cut quality occurred with repeated blade use . Blades showed larger tissue remnants, nicks, and even folds on the cuttin g edge proportional to the number of times blades were used. CONCLUSION: Satisfactory cut quality and reproducibility were obtained afte r a single use of stainless steel blades in the Automated Corneal Shaper mi crokeratome. Cut quality was degraded dramatically by repeated use of blade s.