Quest: Ideal presbyopia therapy

August 15, 2011

An intrastromal procedure performed using a femtosecond laser fulfills many of the criteria for an ideal presbyopic treatment.

Istanbul, Turkey-An intrastromal procedure performed using a femtosecond laser (IntraCor with the Technolas femtosecond laser) fulfills many of the criteria for an ideal presbyopic treatment and may be considered an excellent option for improving near vision in emmetropic and slightly hyperopic presbyopic eyes, said Sinan Göker, MD.

Visual recovery is rapid and patients benefit with significant gains in near vision that have been shown to remain stable during follow-up that now exceeds 2 years, he added.

The femtosecond laser is used to perform a three-dimensional intrastromal ablation in which five or six concentric rings are created at 75% to 80% corneal depth. The rings are placed within a 5-mm zone of the central cornea and spaced about 0.3 to 0.4 mm apart. The ablation takes only about 20 seconds to complete, allows for kappa angle definition, and leaves the epithelium, Bowman's layer, and endothelium intact. Its mechanism of action relates to creation of a hyperprolate cornea with convexity and variable refractive power centrally that improves depth of focus.

"After the ablation, the cornea has increased negative spherical aberrations and asphericity, but the refractive power only centrally so that there is minimal effect on distance vision," Dr. Göker said. Candidates for the procedure are patients with fully developed presbyopia and a clear cornea with a cycloplegic refraction between 0 and +1 D and up to 1 D of cylinder.

Dr. Goker highlighted the results he has achieved in a series of 238 eyes of 154 patients with presbyopia; 95 patients were treated binocularly and 48 had monocular treatment. Over time, the treatment protocol has been modified with respect to laser energy settings, start depths, inner diameter, and ring aperture size. Patients ranged in age from 44 to 60 years with a mean of 51.1 years; mean follow-up duration was almost 1 year.

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