Presbyopia-correcting software enhances LASIK outcomes

Bi-aspheric multifocal ablation profiles reduce spectacle dependence for near vision by increasing depth of focus without minimizing distance vision, surgeon says.

Issue: January 2010

Multifocal ablation profiles generated with a new presbyopia-correcting software package yielded promising and predictable outcomes in eyes undergoing LASIK, according to a study.

Schwind launched its PresbyMax presbyopia-correcting system for use with the Amaris excimer laser and released 1-month study results at the European Society of Cataract and Refractive Surgeons meeting.

“Presbyopia can be compensated at the corneal level by central bi-aspheric correction as demonstrated by the PresbyMax software,” Jorge L. Alió, MD, PhD, OSN Europe Edition Associate Editor and lead study author, told Ocular Surgery News in a subsequent e-mail interview. “Two diopters of corneal pseudoaccommodation can be achieved, which are equivalent to 3 D in an IOL.”

PresbyMAX correction may also benefit pseudophakic patients and those undergoing post-LASIK enhancement, Dr. Alió said.

“Our technique for presbyopia correction through cornea compensation is also able to correct post-LASIK patients,” he said. “This was never reported before and we have proven it in our study. Pseudophakic patients may also benefit from the PresbyMax correction, as we compensate 2 D to 3 D, which is equivalent to 3 D or 4 D at the level of an IOL.”

Multifocal ablation profiles

Dr. Alió and colleagues at Vissum and Miguel Hernández University of Elche, Alicante, Spain, helped Schwind researchers develop bi-aspheric multifocal ablation profiles that PresbyMax delivers to treat emmetropic, myopic, hyperopic and astigmatic patients, according to a Schwind press release.

Jorge L. Alió

“The central development goal of the PresbyMax was to provide the first systemic and scientifically based approach for the correction of presbyopia with excimer laser surgery,” Dr. Alió said in the release.

The ablation profiles ensure a multifocal corneal surface and minimize spectacle dependence for near vision by increasing the depth of focus without diminishing distance vision, the release said.

“Our software is different from others available,” Dr. Alió told OSN. “We do not try to induce aberrations on the cornea but rather to add power to the central cornea, similar to the recently introduced refractive intracorneal inlays. The software from Visx (Abbott Medical Optics) and Allegretto (Alcon) dealt with creating a high level of negative spherical aberration at the cornea, which indeed requires neuroprocessing. Our software does not induce aberrations, so neuroprocessing is expected to be minimal as it is in the study.”

Highly predictable outcomes

The pilot study included 72 eyes: 22 myopic, 36 hyperopic and 14 emmetropic. All patients underwent LASIK with PresbyMax correction performed with an optical zone between 6.5 mm and 7 mm. Preoperative manifest refraction was –4 D to +4 D of defocus, up to 2.5 D of astigmatism and up to 2.5 D of addition. The authors analyzed outcome data for 1 month after surgery.

Study results showed that postoperative binocular logMAR distance uncorrected visual acuity averaged 0.0, or 20/20 Snellen equivalent. The average distance uncorrected visual acuity for myopes matched the targeted value of 0.1.

Binocular logRAD near UCVA averaged 0.1, or the equivalent of J2 reading vision, and matched the target value of 0.1. Binocular near UCVA was 0.3 logRAD, or J5 or better, in 95% of patients.

The study showed that 97% of eyes achieved distance UCVA of 0.2 logMAR or better, the equivalent of 20/32 or better; 75% of patients had uncorrected reading acuity of 0.2 logRAD or better, equivalent to J3 or better and sufficient acuity for newspaper reading.

Additionally, 72% of patients’ distance and near UCVA equaled or exceeded 0.2 logMAR and 0.2 logRAD, respectively. No patients lost more than two lines of distance best corrected visual acuity or near BCVA.

PresbyMax induced about –0.15 D of spherical aberration and –0.15 D of coma aberration for each diopter of addition.

Overall, 92% of eyes achieved the desired refractive result, the release said.

“Complications, at the moment, are not to match the patients’ expectations,” Dr. Alió told OSN. “In order to achieve this, we have created predictive software based on the pupil behavior at different luminance levels and other biometrical parameters of the anterior segment. The predictability of the software has been demonstrated with a P value of .01 in our studies.” – by Matt Hasson

Jorge L. Alió, MD, PhD, can be reached at Vissum Instituto Oftalmologico de Alicante, Avenida de Denia, s/n, 03016 Alicante, Spain; +34-965-150-025; fax: +34-965-151-501; e-mail: jlalio@vissum.com.