Quality assessment model of 3 different microkeratomes through confocal microscopy

To study the quality of the cut created by 3 microkeratomes from 2 different generations using corneal confocal microscopy.

Department of Refractive Surgery, Instituto Oftalmológico de Alicante, Alicante, Spain.

Two different studies were conducted: Study 1 and Study 2. Study 1 was a prospective analysis using confocal microscopy examination data from 2 reference groups: Group A (control) with 20 nonoperated eyes of 20 healthy volunteers, and Group B with 50 eyes of 30 patients operated on with the Bausch & Lomb Automated Corneal Shaper (ACS) microkeratome. Study 2 was a prospective randomized double-masked study in which 40 eyes of 20 patients underwent myopic laser in situ keratomileusis by 1 surgeon. The right and left eyes of each patient were randomly and alternatively assigned to Group C, flap made with the Hansatome microkeratome, or Group D, flap made with the Moria M2. Immediately after surgery, the microscopic appearance of the cut was subjectively evaluated by the surgeon. One month postoperatively, flap thickness, particle density, and the subclinical confocal wound healing opacity (WHO) index were evaluated with the corneal confocal microscope.

Surgeon handling comfort was nearly the same with the Hansatome as with the M2 (P =.540). However, the apparent quality of the resulting flap was better with the M2 microkeratome (P =.041). The depth of the cuts made by the 3 microkeratomes were significantly different (P<.001), with the ACS flaps being thinner than the flaps made with the Hansatome or the M2. Particle density at the interface was significantly poorer in the eyes operated on with the ACS, but in these cases the WHO index was significantly greater (P<.001 in both cases).

Confocal microscopy is a very useful tool to evaluate the quality of the cut made by different microkeratomes. Overall, the predictability in flap thickness and the apparent quality of the cut made by the Moria M2 microkeratome are better than those obtained with the Hansatome or the ACS. The thin flap made by the ACS microkeratome produced a significantly greater WHO index than the thicker flaps created with the other 2 microkeratomes.