Laser-induced modulation of spherical aberration addresses presbyopic hyperopia
A novel bilateral LASIK technique based on modulation of spherical aberration showed efficacy as a treatment for presbyopic hyperopia in a study.
At the Institute of Laser Vision Noémie de Rothschild in Paris, 28 patients aged at least 43 years with hyperopic presbyopia underwent bilateral LASIK using the Custom-Q ablation program of the WaveLight Refractive Suite platform (Alcon), designed to reshape the corneal profile asphericity of the two eyes using opposed aspherical photoablation profiles. Before surgery, soft contact lenses were fitted to assess monovision tolerance and monocular vs. binocular visual performance in uncorrected near and distance vision.
For the surgery, slight hyperopia of 0.5 D was targeted in the dominant eye, with a positive asphericity change of +0.2, to enhance uncorrected near and intermediate vision by creating positive spherical aberration, with increased vergence in the periphery of the entrance pupil area. In the nondominant eye, negative spherical aberration was induced by gradually changing the defocus gradient from the center to the edge of the pupil. The target refraction was –2.50 D, and the more prolate target asphericity was –0.6. This increased prolateness served to induce gradient of refraction toward emmetropia in the non-paraxial area of the pupil.
At 6 months, all patients achieved 20/20 or better binocularly at distance and 20/25 or better binocularly at intermediate, while 93% achieved 20/25 binocularly at near. Only two patients needed re-treatment. Using the National Eye Institute Refractive Error Quality of Life-42 questionnaire, patients were asked to evaluate satisfaction, clarity of vision and symptoms. For all parameters, higher scores were obtained as compared with the values with contact lenses simulating monovision.
“Our study shows promising results,” Damien Gatinel, MD, PhD, who developed the nomogram for this treatment, told Healio/OSN. “The originality of this method is that it uses opposite aspheric profiles, and we were able to demonstrate that it is superior to monovision in terms of visual performance.”