Topography-driven excimer laser for the retreatment of decentralized myopic photorefractive keratectomy.
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 topograph to a flying-spot excimer laser, provides customized laser ablation for correction of postmyopic photorefractive keratectomy (PRK) decentrations.


METHODS
Noncomparative consecutive case series.


METHODS
Thirty-two eyes of 32 subjects with a mean age of 35 years (range, 19-49; standard deviation [SD], 7.9) had CIPTA-guided PRK at the Clinica Oculistica of Bari University (Italy). All the subjects had irregular astigmatism after postmyopic PRK because of clinically significant, decentered treatments of more than 1 mm. OPERATION: Individual topographies were acquired by a corneal topograph (Orbscan II, Orbtek, Inc., Salt Lake City, UT). These, together with refractive data, were processed to obtain a customized altimetric ablation profile that was transferred to a flying-spot laser (Laserscan 2000, Lasersight, Orlando, FL).


METHODS
The topographic study of centration and data on uncorrected (UCVA) and best-corrected (BCVA) visual acuity, predictability, and stability of refraction, and any complications, were analyzed.


RESULTS
Mean follow-up was 10.3 months (range, 4-18 months; SD, 5.8). At the last postoperative examination, 29 eyes (90.6%) had a UCVA superior to 20/40. Nineteen eyes (59.4%) had a UCVA of 20/20. Twenty-two eyes (68.75%) were within 0.50 diopters (D) of attempted correction in the spherical equivalent and 28 eyes (87.5%) were within 1 D. The index of success of astigmatic correction was 0.15. No eye lost Snellen lines of BCVA, whereas 18 eyes (56.25%) gained Snellen lines. Postoperative topographies revealed well-centered treatments.


CONCLUSIONS
The combination of topographic data with computer controlled flying-spot excimer laser ablation is a suitable solution for correcting irregular astigmatism after postmyopic PRK decentrations.
Alessio
G
G
Clinica Oculistica, Department of Otorhinolaryngology and Ophthalmology, University of Bari, Bari, Italy.
Boscia
F
F
La Tegola
M G
MG
Sborgia
C
C
D000328:Adult; D001251:Astigmatism / Q000601:surgery; D003315:Cornea / Q000601:surgery*; D019781:Corneal Topography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular; D012086:Reoperation; D012449:Safety; D012984:Software; D014792:Visual Acuity