February 2018

REFRACTIVE

Presentation spotlight
Laser blended vision for presbyopia provides the full visual spectrum


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer


The laser blended vision program incorporates a non-linear aspheric ablation profile that increases the spherical aberration in both eyes.
Source: Cristian Falcon, MD

A retrospective study shares data on 6 years of experience using laser blended vision in presbyopic patients

Laser blended vision appears to be an excellent option for individuals experiencing age-related loss of accommodation, who may be hoping to avoid an intraocular procedure to achieve spectacle independence. The goal of the technique is to increase the patient’s depth of field by altering the optics of the corneal spherical aberration, which allows a visual correction in which the dominant eye is set for distance and intermediate vision, while the non-dominant eye is set for intermediate and near vision. The common intermediate range of both eyes permits the brain to integrate the images between the eyes, rendering a binocular visual field, which stands in contrast to traditional monovision where a high disparity between the eyes makes image fusion difficult and leads the brain to suppress the one sided blurry image in order to see clearly. In laser blended vision, both eyes work together to see clearly at near, intermediate, and far distances, without the use of glasses.

Retrospective study

A retrospective study of 277 consecutive presbyopic patients (539 eyes) that underwent LASIK with the wavefront-guided laser blended vision program for presbyopia by Carl Zeiss Meditec (Jena, Germany) demonstrated high patient satisfaction with fast adaptation and good outcomes in visual acuity for distance and near. According to Cristian Falcon, MD, OPTIMA LASER Eye Clinic, Valencia, Spain, who presented the study at the XXXV Congress of the ESCRS, laser blended vision is a clear treatment choice for the fast growing demographic of presbyopic patients.
The laser blended vision program incorporates a non-linear aspheric ablation profile that increases the spherical aberration in both eyes. A slight myopia of –1.5 D sphere in the non-dominant eye is programmed.
Dr. Falcon’s study included 120 male (43%) and 157 female (57%) patients from 42 to 71 years of age, of which 12 (4.33%) were between 42 and 44 years, eight (29.96%) were between 45 and 49 years, and 182 (65.7%) were more than 50 years of age. Fifteen patients underwent surgery only in their non-dominant eye, and one patient with myopia underwent surgery only in the dominant eye. The study patients were separated into two groups: patients less than 50 years of age and patients more than 50 years of age. The follow up was between 1 and 47 months. Seventeen (3.15%) patients were emmetropic (0.5 D or less spherical equivalent), 131 (24.3%) were myopic or myopic astigmatic, and 391 (72.54%) were hyperopic or hyperopic astigmatic.
In 97.12% (202 patients) of the hyperopic, hyperopic astigmatic, and emmetropic patients, there was a preoperative near visual acuity of J4–10. Ninety-nine percent (206 patients) had a postoperative near visual acuity of J1–3, and 87.98% achieved J1.
In the myopic patients, 25.37% had a preoperative near visual acuity of J4–10. All of the myopic patients (100%) achieved a postoperative near visual acuity of J1–3, of which 95.52% achieved J1.
The postoperative binocular visual acuity without correction for distance was 20/20 or better in 93.14% of patients, near vision was J1–3 in 99.28%, of which 89.87% achieved J1. The predictability within 0.5 D was 87.94%. The procedure was safe in 99.81% of eyes (538/539 eyes), with only one eye of a diabetic patient losing two lines of BCVA.
In patients younger than 50 years of age, 82.14% achieved distance visual acuity of 16/20 or better in their non-dominant eye. Only 23.8% of patients more than 50 years of age achieved 16/20 in their non-dominant eye, with an average spherical equivalent of –1.5 D.

High satisfaction

Postoperative satisfaction was high among the study patients at 93.86%. Of the 35.37% (98 patients) of the study group that had a follow up longer than 12 months, 95.92% were still satisfied 1 year later. Only 3.61% of patients said the procedure had not accomplished their expectations: 3.61% needed to wear spectacles for some activities, 1.8% experienced eye dryness, and 0.72% experienced non-specific adaptation difficulties.
Enhancements were carried out in 45 eyes (10.11%) of 36 patients, of which 27 patients (75%) had only one eye enhanced. Enhancements were performed in the non-dominant eye in 88.89%. Patient satisfaction improved appreciably after the retreatment.

Well tolerated

Laser blended vision allows spectacle independence by combining the ease and high precision of corneal refractive surgery with the benefits of increased depth of field in retaining visual quality. By using the naturally occurring spherical aberrations of the eye, laser blended vision extends the scope of customized ablation beyond the limits of conventional monovision laser methods in a number of ways. “Laser blended vision for presbyopia is a wavefront-guided treatment that has several mechanisms to increase near vision, while maintaining good distance vision as well, that include micro-monovision, depth of field, spherical aberration, vertex centration, retinal image processing, neural summation, blur adaptation, and neural suppression,” Dr. Falcon said. “A patient’s spherical aberration can increase the circle of least confusion, improving the depth of field.”
Image integration in the brain in vital to refractive corrections that are set at different distances. In an unrelated study, investigators demonstrated the effect of image merging by the brain to see near and far without glasses. The study’s hyperopic monovision protocol was well tolerated by 97% of the study patients that included 258 eyes of 129 consecutive patients with moderate to high hyperopia, hyperopic astigmatism and presbyopia, with corrections up to +5.75 D. Contrast sensitivity was improved, and the distance vision of near eyes was found to contribute positively to binocular distance vision compared to distance eyes monocularly.1
“Laser blended vision for presbyopia has a high percentage of satisfaction for emmetropic, myopic, hyperopic, and astigmatic patients with a fast adaptation and good outcomes in visual acuity for distance and near,” Dr. Falcon said. “The results are as good for younger patients with presbyopia as for older ones. Though they become adapted, patients more than 50 years of age are likely to perceive the difference of vision between the eyes more acutely. Still, patient satisfaction is not always related to visual acuity, as image processing is important to give comfortable vision. The higher percentage of enhancements and higher patient expectations compared to standard LASIK could influence patient satisfaction as well. But we have to remember that achieving all patient expectations is not always possible.”

Reference

1. Reinstein DZ, et al. LASIK for hyperopic astigmatism and presbyopia using micro- monovision with the Carl Zeiss Meditec MEL80 platform. J Refract Surg. 2009;25: 37–58.

Editors’ note: Dr. Falcon has no financial interests related to his comments.

Contact information

Falcon: drcristianfalcon@gmail.com

Laser blended vision for presbyopia provides the full visual spectrum Laser blended vision for presbyopia provides the full visual spectrum
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