Flap lift re-treatment after femtosecond laser-assisted LASIK achieves notable clinical results

Study also finds flap relift easier to perform in the first 6 to 8 months after primary LASIK.

Issue: September 10, 2012

Femtosecond laser-assisted LASIK allows for impressive results with flap lift re-treatment to remedy residual refractive error, according to a study.

Of the nearly 90% of eyes included in the retrospective analysis that completed re-treatment, 82% achieved 20/20 or better uncorrected visual acuity.

The overall re-treatment rate of 6.8% compares favorably to microkeratome LASIK and PRK reports, according to the study authors.

“While it is often possible to safely relift a microkeratome flap 10 or more years after the original LASIK surgery, it is thought that at least in some eyes, it may be more difficult to relift flaps even months after LASIK performed with the femtosecond laser,” lead study author Marcony R. Santhiago, MD, PhD, head of the cataract and refractive surgery department and professor of ophthalmology at the Federal University of Rio de Janeiro in Brazil, said.

This common belief derives from an investigation of early models of femtosecond lasers that demonstrated an increased inflammatory reaction and improved subsequent wound healing, Santhiago told Ocular Surgery News.

“Hence, stronger healing at the flap margin and within the interface with femtosecond lasers was a concern in corneas that undergo LASIK enhancement for residual refractive error,” Santhiago said.

Study design, findings

Marcony R. Santhiago

Santhiago and colleagues undertook a study, which was published in the Journal of Refractive Surgery, to validate the clinical perception that later models of femtosecond lasers enable safe and effective flap relifts with reliable results.

“More specifically, the purpose of the study was to investigate the difficulties encountered and the results achieved during LASIK re-treatment in eyes that originally had femtosecond laser flaps,” according to Santhiago, who at the time of the study was a cornea and refractive surgery fellow at Cleveland Clinic’s Cole Eye Institute.

Of 1,298 consecutive eyes of 688 patients who underwent femtosecond laser-assisted LASIK who were included in the study, 88 eyes of 71 patients underwent attempted flap relift.

Flap relift was abandoned in 10 eyes because the strength of healing at the flap margin or in the interface posed a risk for flap tear or damage.

The mean age of re-treatment patients was 44.2 years (range: 21 to 65 years), and 63% of eyes were from female subjects. All re-treatments were performed by a single surgeon between 2006 and 2011. Only one procedure was required in 96.6% of eyes, while 3.4% of eyes needed two enhancements in the same eye.

There were no significant differences between eyes with successful flap relift and those in which the relift attempt had to be abandoned, including in terms of the stromal bed and side-cut energies. However, enhancement is best performed in the first 6 to 8 months after the primary LASIK procedure, Santhiago said.

Eyes in which the flap relift attempt had to be abandoned had an average lapse of 10.3 months from original LASIK, compared to only 5.24 months for those with successful relift.

“Thus, flap relift should not be postponed if residual errors are documented,” Santhiago said.

When a flap relift is not possible because of the risk of flap injury due to strong healing of the original femtosecond laser interface, Santhiago and colleagues prefer enhancing the original LASIK using PRK with mitomycin C.

New flap lift technique

Recently, Steven E. Wilson, MD, who performed all enhancements in the study, and Santhiago described a flap lift technique that has a low incidence of epithelial ingrowth and is highly effective.

“Briefly, a Sinskey hook is pressed into the epithelium at the limbus approximately opposite the hinge and dragged, with posterior pressure, toward the center of the flap until the instrument tip falls into the potential space at the flap edge,” Santhiago said.

Using the Sinskey hook tip, the flap margin is then opened at 1 o’clock. The edge of the flap is grasped gently with 0.12-mm forceps and retracted back across the superior conjunctiva.

Wilson and colleagues have also shown that the difference in terms of healing between later models of femtosecond lasers, such as the 60-kHz and 150-kHz IntraLase lasers (Advanced Medical Optics), and the microkeratome is less pronounced, to the point that there is no distinguishable difference in inflammatory reaction, Santhiago said. – by Bob Kronemyer

Reference:

Santhiago MR, Smadja D, Zaleski K, Espana EM, Armstrong BK, Wilson SE. Flap relift for re-treatment after femtosecond laser-assisted LASIK. J Refract Surg. 2012; 28(7):482-487.

For more information:

Marcony R. Santhiago, MD, PhD, can be reached at 3100 Av. Abelardo Bueno, Apt. 604, Barra da Tijuca, Rio de Janeiro, RJ 22775-040, Brazil; 55-21-24387230; email: marconysanthiago@hotmail.com.
Disclosure: Santhiago has no relevant financial disclosures.