May 2004
Volume 45, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2004
Comparison of corneal forward shift after LASIK and PRK
Author Affiliations & Notes
  • Y. Okamoto
    Dept Ophthalmology, University Tsukuba, Tsukuba, Japan
  • M. Sato
    Dept Ophthalmology, University Tsukuba, Tsukuba, Japan
  • T. Kiuchi
    Dept Ophthalmology, University Tsukuba, Tsukuba, Japan
  • T. Oshika
    Dept Ophthalmology, University Tsukuba, Tsukuba, Japan
  • T. Tokunaga
    Dept Ophthalmology, Miyata Eye Hosipital, Miyakonojo, Japan
  • K. Miyata
    Dept Ophthalmology, Miyata Eye Hospital, Miyakonojo, Japan
  • T. Yoshida
    Canon Sales, Canon Corporation, Tokyo, Japan
  • Footnotes
    Commercial Relationships  Y. Okamoto, None; M. Sato, None; T. Kiuchi, None; T. Oshika, None; T. Tokunaga, None; K. Miyata, None; T. Yoshida, None.
  • Footnotes
    Support  none
Investigative Ophthalmology & Visual Science May 2004, Vol.45, 210. doi:
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    • Get Citation

      Y. Okamoto, M. Sato, T. Kiuchi, T. Oshika, T. Tokunaga, K. Miyata, T. Yoshida; Comparison of corneal forward shift after LASIK and PRK . Invest. Ophthalmol. Vis. Sci. 2004;45(13):210.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Abstract: : Purpose: It has been reported that both laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) induce corneal forward shift after surgery. We compared the time course of changes in corneal antero–posterior shift after LASIK and PRK. Methods: Subjects were 46 eyes of 24 patients (36 ± 11 y.o.) undergoing LASIK and 46 eyes of 25 patients (33 ± 11 y.o.) undergoing PRK. The amount of myopic correction and laser ablation were 5.9 ± 2.1D and 61.5 ± 21.2µm for LASIK, and 6.0 ± 1.8D and 69.0 ± 19.0µm for PRK. Corneal topography of the posterior corneal surface was obtained with the scanning–slit topography system (Orbscan II, Bausch & Lomb) before and 1 week, 1, 3, 6, and 12 months after surgery. Changes in the elevation of the posterior corneal surface were evaluated at the center of the difference map generated from preoperative and postoperative elevation maps. For surface alignment in the difference map, the 3–mm wide peripheral annular fit–zone was used. Results:After LASIK, corneal forward shift reached its maximum at 1 month (56.3 ±27.1µm), followed by a gradual decrease to 43.8 ± 20.6µm at 1–year postoperatively, which was significantly smaller than the 1–month value (p<0.01, Dunn multiple comparison). After PRK, corneal forward shift progressed with time, and the amount of forward shift was significantly larger at 1 year (62.5 ± 49.2µm) than at 1 week (42.4 ± 27.9µm) (p<0.01). Shift curves after LASIK and PRK crossed at 3 months postoperatively. Conclusions: The time–course of changes in corneal forward shift after LASIK and PRK are different in their pattern and magnitude. After LASIK, changes were more pronounced immediately after surgery, and somehow recovered thereafter. After PRK, changes were progressive even after 3 months.

Keywords: refractive surgery: LASIK • refractive surgery: PRK • refractive surgery 
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