Topography-driven photorefractive keratectomy

Results of corneal interactive programmed topographic ablation software

Giovanni Alessio, MD1, Francesco Boscia, MD1, Maria Gabriella La Tegola, MD1 and Carlo Sborgia, MD1

1 Cattedra di Ottica Fisiopatologica, Department of Otorhinolaryngology and Ophthalmology, University of Bari, Bari, Italy

Reprint requests to Carlo Sborgia, MD, Department of Otorhinolaryngology and Ophthalmology, University of Bari, Piazza Giulio Cesare, 11 Bari, Italy

Objective: This study evaluated the efficacy, predictability, stability, and safety of a software program (Corneal Interactive Programmed Topographic Ablation (CIPTA) LIGI, Taranto, Italy) which, by transferring programmed ablation from the corneal topography to a flying-spot excimer laser, provides customized laser ablation.

DESIGN: Noncomparative consecutive case series.

PARTICIPANTS: Forty-two eyes of 34 subjects with a mean age of 33.9 (range, 2054) had CIPTA at the Cattedra di Ottica Fisiopatologica of Bari (Italy). Twenty-eight eyes were treated for hyperopic astigmatism and 14 for myopic astigmatism. All the subjects had irregular astigmatism.

OPERATION: Topography was acquired by a corneal topography mapping system (Orbscan, Orbtek, Inc., Salt Lake City, UT). These data were processed to obtain a customized altimetric ablation profile, which was transferred to a flying-spot laser (Laserscan 2000, Lasersight, Orlando, FL).

MAIN OUTCOME MEASURES: Data on uncorrected (UCVA) and best-corrected visual acuity (BCVA), predictability, and stability of refraction and any complications were analyzed.

RESULTS: Mean follow-up was 13.2 months. At the last postoperative examination, 26 eyes (92.8%) in the hyperopic group and 12 eyes (85.7%) in the myopic group had an UCVA superior to 20/40. Twelve hyperopic eyes (42.8%) and five myopic eyes (35.7%) had a UCVA of 20/20. All patients fell between 1 diopter of attempted correction in the spherical equivalent. Only 1 (2.4%) of the 42 eyes, belonging to the hyperopic group, lost 1 Snellen line of BCVA. We did not observe any decentration and/or haze after photorefractive keratectomy treatment or any irregularity in the flap-stroma interface in the three laser in situ keratomileusis operations performed in this study.

CONCLUSIONS: The combination of topographic data with computer-controlled flying-spot excimer laser ablation is a suitable solution for correcting irregular astigmatism due to different causes.