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IntraLase-enabled astigmatic keratotomy for post-keratoplasty astigmatism: on-axis vector analysis
Nikhil L Kumar1, Igor Kaiserman, Raneen Shehadeh-Mashor
1Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, University of Toronto, Ontario, Canada. nik_kumar1@yahoo.com
Ophthalmology
|February 19, 2010
Summary
Femtosecond laser-enabled astigmatic keratotomy effectively reduces high astigmatism after corneal transplant, improving vision. While generally safe, further research can refine accuracy for better cylinder reduction.
Area of Science:
- Ophthalmology
- Corneal Surgery
- Refractive Surgery
Background:
- Post-keratoplasty astigmatism can significantly impair visual acuity.
- High astigmatism (>5 diopters) after penetrating keratoplasty presents a surgical challenge.
- Femtosecond laser technology offers a precise approach to corneal surgical procedures.
Purpose of the Study:
- To evaluate the refractive predictability, stability, efficacy, and safety of femtosecond laser-enabled astigmatic keratotomy (IntraLase-enabled astigmatic keratotomy) for correcting high astigmatism following corneal transplantation.
- To assess visual acuity outcomes and complication rates associated with this procedure.
Main Methods:
- A retrospective pilot study was conducted on 37 eyes of 34 patients.
- All participants underwent IntraLase-enabled astigmatic keratotomy to correct high astigmatism (>5 D) after penetrating keratoplasty.
- Outcomes measured included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, higher-order aberrations, and complications.
Main Results:
- Mean follow-up was 7.2 months.
- Significant improvements were observed in UCVA (P=0.0016) and BCVA (P=0.018).
- Absolute astigmatism was substantially reduced (from 7.46 D to 4.77 D, P=0.0001), and the defocus equivalent decreased by over 1 D (P=0.025).
- Higher-order aberrations increased significantly. Complications included graft rejection in 8% and overcorrection in 24% of eyes; no perforations or infectious keratitis occurred.
Conclusions:
- IntraLase-enabled astigmatic keratotomy demonstrates effectiveness and encouraging refractive predictability for managing high astigmatism after penetrating keratoplasty.
- The procedure offers a viable option for visual rehabilitation in this patient group.
- Further research is warranted to optimize treatment parameters for enhanced accuracy in cylinder reduction.
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