APR 24, 2013
This prospective study found that the femtosecond laser allows for effective creation of precise, purely intrastromal, arcuate incisions with an excellent safety profile, rapid recovery, and visual stability in patients with mild to moderate astigmatism.
To the authors' knowledge this is the first report on the feasibility, efficacy and safety of an intrastromal arcuate keratotomy for reduction of corneal astigmatism in human eyes.
The authors used an iFS femtosecond laser (Abbott Medical Optics) to perform paired arcuate cuts on the steep axis completely placed within the corneal stroma in 16 patients with minor to medium corneal astigmatism (0.75 to 3.0 D). The particular incision pattern was designed to maximize the effect of the incision using a 90-degree arc length and a 30-degree cut angle in the hope of obtaining a stable final effect by creating a large healing area while minimizing glare with a comparatively large optic zone diameter. No perforations occurred, and all incisions were placed at the planned locations.
Six months after surgery, there was a mean 76.6 percent reduction in absolute refractive astigmatism and a 58 percent reduction in absolute topographic cylinder, as well as an improvement in UDVA. The authors note that these results compare favorably with the reductions seen with anteriorly penetrating femtosecond-enabled arcuate keratotomy.
They write that the astigmatic effect can be increased as the nomogram is further refined. However, a larger series is needed to refine the outcomes and predictability of this new procedure.