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Wavefront-guided LASIK shown safe, effective for up to 4.5 D of hyperopia
Study with Technolas laser showed safety, efficacy and predictability of wavefront-guided LASIK in hyperopes up to +4.5 D.
Hyperopic wavefront-guided LASIK was safe, effective and predictable when performed on patients with up to 4.5 D of hyperopia using the Bausch & Lomb Technolas Keracor laser, a study found.
Sukumaran Ramanathan, MD, FRCS, presented results of the procedure in 26 eyes at the American Society of Cataract and Refractive Surgery meeting. All eyes but one had a postoperative refraction within ±1 D of goal, he said.
“We are all happy treating hyperopic patients with Planoscan [the conventional, non-wavefront-guided algorithm for the Technolas laser] but when it comes to wavefront-guided treatment, we have to take into consideration the higher-order aberration corrections and predicted phoropter refraction,” Dr. Ramanathan said in his presentation. “Where do we set the treatment refraction?”
In a follow-up interview, Dr. Ramanathan elaborated: “Hyperopic LASIK is a challenge in setting the treatment refraction, as the cycloplegic and non-cycloplegic refraction can vary significantly,” he said. “Correlating this with the predicted phoropter refraction makes it more complex; hence the need for this study.”
The study
Dr. Ramanathan’s study included 26 eyes of 14 patients. Two eyes were excluded because iris recognition failed. The limit of hyperopic correction in the study was +4.5 D. Mean refraction was less than 2.29 D with a standard deviation of +0.84 D. Mean follow-up was 3 months.
The Bausch & Lomb Technolas Keracor 217 Z100 laser with the Zyoptix Personalized Zylink 2.31 system was used for all patients. The microkeratome used was the Bausch & Lomb Hansatome.
“The patients in the study had a refractive error of +4.50 D manifest spherical equivalent or less,” he explained in the interview. “We do not want to make the cornea too steep after treatment. It is important to note the anterior corneal curvature preoperatively. I would not advise hyperopic correction on very steep corneas.”
Dr. Ramanathan used a formula to devise what his treatment refraction would be.
“I took the fogged subjective refraction of the patient and added half the difference between the fogged subjective refraction and the cycloplegic refraction, and set that as the treatment refraction,” he said.
“The predictor for optical refraction should be within 0.5 D of my treatment refraction, otherwise I wouldn’t be able to treat it,” he said in his presentation. “Also, the axis should be between 15· of my subjective refraction.”
The results
Twenty-five eyes – all but one included in the study – had a postoperative refraction within ±1 D of the correction goal, Dr. Ramanathan said. Best corrected vision of 20/40 or better was achieved in 100% of patients, including nine amblyopic eyes, he added.
Uncorrected visual acuity of 20/40 was achieved in 21 eyes in the series, again including the nine amblyopic eyes, he said.
To ensure a good outcome, Dr. Ramanathan gave the following advice to surgeons: “Treatment aim should be to treat full cycloplegic refraction; predicted phoropter refraction should be a good match, and iris recognition should be available.”
Only one patient was dissatisfied with the uncorrected vision after surgery and was planning to undergo enhancement, Dr. Ramanathan said. Three patients complained of complications including night vision problems and glare, he said.
“In conclusion, predictability was quite good but showed a trend toward a slight undercorrection. Being my first series of cases, I have been conservative in setting the treatment refraction,” Dr. Ramanathan said. “Larger studies are required to validate these results.”
For more information:
- Sukumaran Ramanathan, MD, FRCS, can be reached at 3 Albion Place, Hammersmith, London, England W6 0QT; e-mail: ramanathan@ntlworld.com.
- Katrina Altersitz is an OSN Staff Writer who covers all aspects of ophthalmology.