Flap measurements with the Hansatome microkeratome.
OBJECTIVE
To evaluate flap thickness, flap diameter, and hinge length during laser in situ keratomileusis (LASIK) and to correlate these measurements with preoperative keratometric power, central corneal thickness, and patient refraction, gender, and age.


METHODS
In this prospective study of 50 eyes of 28 patients (mean age 31 +/- 6.6 yr; range, 24 to 43 yr) results of LASIK for myopia were analyzed (mean spherical equivalent refraction of -7.16 +/- 1.69 D; range, -2.75 to -13.50 D). Corneal flaps were created using the Hansatome microkeratome (Baush & Lomb Surgical) with a 160-microm plate and a 9.5-mm suction ring. Corneal thickness was evaluated using an ultrasonic 50-MHz pachymeter (Sonogage Corneo Gage Plus) and the mean keratometric power was measured with a Corneal Analysis System videokeratographic unit (EyeSys). Data were analyzed using t-test, Pearson product moment correlation coefficient, and Spearman's rho non-parametric correlation coefficients.


RESULTS
Mean corneal flap thickness was 142.6 +/- 20.8 microm (range, 107 to 177 microm), mean flap diameter was 9.9 +/- 0.3 mm (range, 9.2 to 10.5 mm), and mean hinge length was 6.2 +/- 0.4 mm (range, 5.2 to 7 mm). Statistically significant correlations (P<.05) were found between mean keratometric power and flap hinge length, mean keratometric power and flap diameter, preoperative spherical equivalent refraction and flap diameter, corneal thickness and flap hinge length, as well as patient age and corneal thickness.


CONCLUSIONS
The Hansatome microkeratome was an effective and safe instrument in the creation of corneal flaps for LASIK. Consideration of preoperative keratometric power and corneal thickness may help to reduce or avoid complications.
Spadea
Leopoldo
L
Department of Ophthalmology, University of L'Aquila, Italy. lspadea@cc.univaq.it
Cerrone
Loredana
L
Necozione
Stefano
S
Balestrazzi
Emilio
E
D000328:Adult; D003319:Corneal Stroma / Q000473:pathology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation*; D008297:Male; D009216:Myopia / Q000601:surgery; D011446:Prospective Studies; D012029:Refraction, Ocular; D013524:Surgical Flaps / Q000473:pathology*