Posters

Femtosecond laser-assisted arcuate keratotomies for the correction of post-keratoplasty astigmatism: a predictive regression algorithm based on vector analysis

Poster Details

First Author: L.Mosca ITALY

Co Author(s):    L. Guccione   U. De Vico   M. Toro   R. Fasciani   O. Caporossi   A. Caporossi     

Abstract Details

Purpose:

To report the long-term refractive results of the correction of high post-keratoplasty astigmatism with femto-assisted arcuate keratotomies (AK), performed with an optimized parameter setting; to use of a new algorithm based on vectorial analysis of keratometry data, to identify specific regression patterns of the correction; to  assess the effectiveness of analysis-guided re-treatments.

Setting:

Catholic University of Sacro Cuore Agostino Gemelli Polyclinic Foundation - Rome, Italy

Methods:

25 eyes were submitted, six years from Penetrating Keratoplasty , to AK to correct an average of 9.1 D of astigmatism. The incisions performed with the femtosecond laser (IntraLase; Abbott Medical Optics; Inc. CA), at  85% of depht with an inclination of 125°. The arc length of the incisions was based on the topographical pattern of astigmatism. A vector analysis of the keratometric data was conducted. The indexes showed the existence in our series of four distinct regression patterns of the correction, united by the same ranges for certain indices (Coupling Ratio, Flattening Index, Index Of Success).

Results:

the incisional procedure reduces the pre-operative average of 9.1 D of astigmatism by 56% at six months, and by 44% at 56 months of follow-up. The vectorial analysis highlights the existence in our series of 4 distinct subgroups united by characteristic correction regression patterns. In the course of follow-up recourse was used in 36% of cases. There were no complications related to the procedure and / or connected to the survival of the flap. In only one case the diastases of the incision margins required suturing.

Conclusions:

A stable reduction in astigmatism in 64% of patients in one step was reported; the vectorial analysis can be suggested as an ally for the surgeon in the not easy interpretation of the keratometric data; where the recurrence of a high astigmatism compromises the functional recovery, the targeted re-treatments, chosen on the basis of the regression pattern, have proved to be rehabilitating in all cases.

Financial Disclosure:

None