Flap thickness variation with 3 types of microkeratome heads

To determine flap thickness variation with 3 types of microkeratome heads and identify the potential factors that affect flap thickness.

Ruijin Hospital, Department of Ophthalmology, Shanghai, China.

Comparative case series.

Laser in situ keratomileusis was performed using the Moria microkeratome with the One Use-Plus SBK, M2 90, or M2 110 head. Flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness (CCT), spherical equivalent refraction, mean keratometry, and horizontal corneal diameter were recorded preoperatively.

The study comprised 180 eyes of 90 patients; 60 eyes were treated with each head. The difference in mean flap thickness between right and left eyes was not significant in the SBK group (97.50 μm ± 11.39 [SD] versus 96.73 ± 10.45 μm; P = .44) but was significant in the M2 90 group (128.03 ± 12.03 μm versus 123.40 ± 12.38 μm; P = .0071) and the M2 110 group (140.53 ± 15.14 μm versus 135.23 ± 18.03 μm, P = .0035). The difference from the intended flap thickness (right eyes and left eyes) was 2.50 ± 11.39 μm and 3.27 ± 10.45 μm, respectively, in the SBK group; -8.03 ± 12.03 μm and -3.40 ± 12.38 μm, respectively, in the M2 90 group; and -0.53 ± 15.14 μm and 4.77 ± 18.03 μm, respectively, in the M2 110 group. Flap thickness was positively correlated with baseline CCT in each group.

Flap thickness was positively correlated with the preoperative CCT using the Moria microkeratome. The SBK head demonstrated the most accurate flap thickness, followed by the M2 90 head and the 110 head.

No author has a financial or proprietary interest in any material or method mentioned.