240 Les caractéristiques des capots avec le nouveau microkératome One Use-Plus 90

Abstract

To assess the safety and efficiency of the new One Use- Plus 90 microkeratome and to evaluate the flap characteristics. 132 eyes of 72 patients had LASIK using the new One Use- Plus 90 microkeratome. In 47 eyes (36%), the ring size and the microkeratome head stop settings were determined according to the nomogram recommended and in 85 eyes (64%), the -1 ring size with 8.0 head stop were used. The microkeratome was set to Speed 1 in 85 eyes (64%) and to Speed 2 in 47 eyes (36%). The central corneal thickness was measured before and after the flap cut using an ultrasound pachymeter and the central flap thickness was calculated using the subtraction method. The vertical and horizontal flap diameters as well as the hinge width were measured using a caliber. Quality of the stromal bed as well as the characteristics of the flap created are evaluated in relation to the microkeratome used. The mean preoperative pachymetry was 537.3 μm ± 32.5, the mean central flap thickness was 106 μm ± 11. The mean vertical flap diameter was 9 mm ± 0.38, while the mean hinge width was 4.2 mm ± 0.6. In the eyes where the nomogram for the ring size and head stop had was followed, smaller hinge width (mean 3.9 mm ± 0.7) was noted compared to non-nomogram eyes in which the hinge width was 4.3 mm ± 0.53 ( p 0.000). Speed 2 provided a larger hinge width (4.2 mm ± 0.64) compared to Speed 1 (4 mm ± 0.53) p 0.008. There were significant positive correlations between both the steepest and the average preoperative K and the thickness, vertical and horizontal diameters of the flap. Moreover, a significant positive correlation was found between the vertical diameter and the hinge width of the flap ( r 0.03). On the other hand, Preoperative central corneal thickness had no significant effect on the characteristics of the flap. The stromal beds were smooth in all eyes and the flaps were of a good quality. Insignificant irregularities at the edges of the bed near the hinge were present in 20 eyes (15%). The new One Use- Plus 90 microkeratome provides an easy and efficient technique for cutting good quality and predictable Lasik flaps. Good quality stromal beds and thin flaps could be efficiently obtained using the One Use- Plus 90 microkeratome.