Abstract
Purpose: :
To evaluate the difference between planed and measured corneal flap thickness after LASIK with three equipments to create the corneal flap.
Methods: :
90 eyes of 45 patients underwent LASK, corneal flaps were created by 3 different equipments: Group A: 30 eyes done by using the Hansatome microkeratome (Chiron Vision Corp, Claremont, Calif) to create a planed 160µm corneal flap, Group B: 30 eyes done by using the BD K-300 microkeratome (BD Ophthalmic Systems, Waltham, Mass) to create a planed 130 µm corneal flap, and group C: 30 eyes done by using the Femtosecond surgical laser (IntraLase Corp, Irvine, Calif) to create a planed 100 µm corneal flap. A Visx star 4 system (Visx, Santa Ana, CA, USA) was used to perform the laser ablation in all eyes. A central scan of the total corneal thickness was taken with the confocal microscope (Confoscan 4, Fortune Technologies, Italy) at 2 weeks after surgery. Corneal flap thickness was measured by using the NAVIS software V. 3.5.0 (NIDEK, Multi-Instrument Diagnostic System, Japan).
Results: :
Measured mean flap thickness after LASIK at group A was thinner than planed (146.5 ± 20.3 µm P < 0.05). Measured mean flap thickness after LASIK at group B was not statistically significant different compared to planed (11.7 ± 12.9 µm P= 1.37). Measured mean flap thickness after LASIK at group C was thicker than planed (10.9 ± 13.8 µm P < 0.05)
Conclusions: :
We found in only one of the three evaluated systems to create the corneal flap a not statistically significant difference between planed vs measured thickness but all of them showed more than 10 µm SD of measured thickness.
Clinical Trial: :
www.clinicaltrials.gov NCT00558324
Keywords: refractive surgery: LASIK • cornea: stroma and keratocytes • laser