Study shows similar accuracy with mechanical, laser microkeratomes

CHICAGO — LASIK flaps created with a mechanical microkeratome achieved more consistent and accurate intended flap thickness with a lower total surgery time than flaps created with a femtosecond laser, a study presented here found.

Hung Ming Lee, MD, of Tan Tock Seng Hospital in Singapore, discussed the prospective, randomized, contralateral trial of corneal flaps for LASIK using the Zyoptix XP microkeratome (Bausch & Lomb) and the IntraLase FS femtosecond laser at a press breakfast presentation here at the American Academy of Ophthalmology meeting.

Dr. Lee performed bilateral surgery in 50 patients using the Zyoptix XP to create the flap in one eye and the IntraLase FS in the other.

Users of the Zyoptix XP “can expect to achieve the same level of precision, predictability and outcomes that have been ascribed to the latest generation laser flap-creation technology,” Dr. Lee said.

For the study, Dr. Lee used an intended flap thickness of 120 µm. The Zyoptix flaps were a mean 4 µm thinner than the IntraLase flaps according to ultrasound pachymetry and they 11 µm thinner according to optical coherence pachymetry, he said.

The study found a similar standard deviation in flap thickness with the two devices, Dr. Lee said. The Zyoptix XP flaps had a standard deviation of 16.1 µm as measured with ultrasound and 14.4 µm as measured with optical coherence pachymetry, while the IntraLase flaps had standard deviations of 16.2 µm and 15.9 µm, respectively.

Dr. Lee said he still uses both the IntraLase and the Zyoptix microkeratomes in his current practice, and he estimated that he uses them in an equal number of procedures.

“The results of this contralateral study have demonstrated that both technologies deliver excellent performance and precision,” Dr. Lee said, “but more importantly to me, the visual outcomes are equivalent in both high and low contrast conditions.”