Related Experiment Video
Updated: May 20, 2026
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Analysis of photoastigmatic keratectomy with the cross-cylinder ablation
Nicola Rosa1, Maddalena De Bernardo, Mario R Romano
1Eye Department, and Centro Grandi Apparecchiature, 2nd University of Naples, Via De Crecchio 16, Naples, Italy.
Aim:
The aim was to evaluate the safety and efficacy of the "cross-cylinder" technique in the correction of astigmatism.
Setting And Design:
A prospective interventional study from a university eye department was conducted.
Material And Methods:
The photoastigmatic refractive keratectomy (PARK) using the "cross-cylinder" technique was performed in 102 eyes of 84 patients with at least 0.75 D of astigmatism. The study population was divided into two groups: in the first group the preoperative astigmatic power ranged from -0.75 D to -3.00 D (group 1), in the second group it ranged from -3.25 D to -6.00 D (group 2). Group 1 included 82 eyes of 67 patients (29 males and 38 females) with a mean cylinder power of -1.90 ± 0.63 D, group 2 included 20 eyes of 17 patients (13 males and 4 females) with a mean cylinder power of -4.28 ± 0.76 D. All eyes were targeted for emmetropia. The results were evaluated using Calossi's vector analysis method. Six-month postoperative outcomes are presented.
Results:
Six months after PARK the mean sphere for the entire cohort was +0.28 ± 0.75 D (range +2.5 to -2 D), the mean cylindrical power was +0.33 ± 0.51 D (range +2.5 to -1.25 D) and the mean spherical equivalent refraction was +0.73 ± 0.81 D (range +1.75 to -2 D).
Conclusions:
The cross-cylinder technique may be safely used with predictable results for the correction of astigmatism.
