Presby-LASIK is an option for hyperopic presbyopic patients, surgeon says

The technique is based on creating a multizone corneal surface, with three concentric zones.

ByMichela Cimberle

Jorge L. Alió

BARCELONA – Presby-LASIK with Technovision Presby-One software is a predictable, effective and safe technique for the correction of presbyopia in low to moderate hyperopic patients, according to Jorge L. Alió, MD, PhD.

“Subjectively, patients report a marked improvement in the quantity and quality of visual performance, both at distance and near, although a small amount of additional correction is necessary for highly demanding visual tasks,” he said at the winter meeting of the European Society of Cataract and Refractive Surgeons.

The technique is based on the creation of a multizone corneal surface, where three concentric optical zones are used for distance, intermediate and near vision. Simultaneous vision is made possible by a mechanism of neurosensory dissociation, he said.

“According to the distance from which the object is viewed, one of the images will be focused better, while the other images will be unfocused. The unfocused images will then be neutralized by neuro-sensorial adaptation of the cortex,” Prof. Alió explained.

He pointed out that with multifocal implants or contact lenses, neurosensorial adaptation takes place over time postoperatively: The patient progressively accepts the new way of seeing. After Presby-LASIK, there is a phase of decrease in far vision (one to two lines), which can last 3 to 4 weeks, and contributes to progressive adaptation to simultaneous vision.

The excimer laser used by Prof. Alió is the Technovision, a modified version of the Bausch & Lomb Technolas 217 Z. The final corneal profile results from the combination of three consequent concentric ablations.

“We perform an optical zone of at least 6 mm for distance vision. A central addition of +0.75 to 2 D creates a central 3-mm optical zone for near vision, and the transition zone between the two is used for intermediate vision,” Dr. Alió explained.

Patient selection

Presby-LASIK has a wide range of possible applications, but so far Prof. Alió has treated only hyperopic patients. Selection criteria included a distance spectacle correction of less than 4.5 D, astigmatism less than –2 D and near visual acuity of at least 20/40 with an add of +1.5 D.

“The other inclusion criteria were the same as in normal LASIK,” he pointed out. “Corneal topography should show no sign of keratoconus or irregular astigmatism and corneal thickness should be not less than 500 µm. Keratometry should be between 39 D and 48 D and scotopic pupil diameter should be less than 2.5 mm.”

As for other types of multifocal correction, psychological and social aspects are also crucial for selecting patients. Needs and expectations should be evaluated, and candidates must be prepared to accept a period of adaptation and the occasional use of spectacles for reading very small characters.

A high degree of satisfaction

Prof. Alió treated a total of eight hyperopic presbyopic patients (16 eyes) age 53 to 62 years. They were examined preoperatively and at 1 and 3 months after Presby-LASIK. Quantity and quality of vision were evaluated at each visit by measuring visual acuity, contrast sensitivity in mesopic conditions, corneal aberrations and patient satisfaction.

Preoperative mean spherical equivalent was 2.04 D ± 0.71 D (range 3.25 D to 1.25 D). Mean cylinder was –0.56 D ± 0.41 D (range –1 D to 0 D).

Three months after surgery the mean spherical equivalent was –0.06 D ± 0.41 D (range –0.5 D to 1 D), and the mean cylinder was +0.41 D ± 0.40 D (range –1 D to 0 D).

Distance uncorrected visual acuity was 20/25 and distance best corrected visual acuity was very near 20/20.

“These patients had also a very good near vision,” Prof. Alió pointed out. “Near UCVA was 20/32 and near BCVA was 20/20. Distance-corrected near vision, which is a very significant data, was 20/32.”

Subjectively, the majority of patients reported a high degree of satisfaction, and none of the patients were unhappy with the results, he said. Predictability was achieved in 70% of the cases.

Visual quality

The measurement of contrast sensitivity is a very important parameter, said Prof. Alió, because multifocality is often associated with contrast sensitivity loss.

“There was no significant difference between preoperative and postoperative contrast sensitivity, which means that contrast sensitivity is hardly affected at all by this technique,” he said.

Corneal aberrations were another controversial point because a multifocal cornea could potentially increase aberrations. Coma in particular could be increased by even very small decentrations in the ablation pattern, he said.

“There was no significant change in higher-order aberrations after surgery, but just a negligible increase from 0.56 to 0.58 at 3 months,” Prof. Alió said.

He also compared the preoperative and postoperative point spread function (PSF).

“The PSF is a new parameter which, in our experience, correlates well with clinical performance. A poor PSF is subjectively perceived as poor visual quality,” he noted.

Three months after Presby-LASIK the PSF was unchanged in all patients.

“Results in our series were very satisfactory, and we might conclude that Presby-LASIK with Presby-One is a very good and perhaps the best option for hyperopic-presbyopic patients,” he said.

For Your Information:
Jorge L. Alió, MD, PhD, can be reached at Instituto Oftalmologico de Alicante, Avda de Denia, 111, 03015 Alicante, Spain; +34-965-150-025; fax: +34-965-151-501; e-mail: jlalio@oftalio.com.
Michela Cimberle is an OSN Correspondent based in Asolo, Italy.