Topography-driven excimer laser for the retreatment of decentralized myopic photorefractive keratectomy

Ophthalmology. 2001 Sep;108(9):1695-703. doi: 10.1016/s0161-6420(01)00706-0.


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.

Design: Noncomparative consecutive case series.

Participants: 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).

Main outcome measures: 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.

Publication types

  • Case Reports
  • Evaluation Study

MeSH terms

  • Adult
  • Astigmatism / surgery
  • Cornea / surgery*
  • Corneal Topography / instrumentation
  • Corneal Topography / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Lasers, Excimer
  • Male
  • Middle Aged
  • Myopia / surgery*
  • Photorefractive Keratectomy / methods*
  • Refraction, Ocular
  • Reoperation
  • Safety
  • Software
  • Visual Acuity