Six-month clinical outcomes of customized treatments minimized for depth and time in laser corneal refractive surgery.
OBJECTIVE
Evaluating the application of 2 methods for minimizing the ablated tissue upon objective minimization of depth and time of Zernike-based customized ablations.


METHODS
Muscat Eye Laser Center, Muscat, Sultanate of Oman.


METHODS
Recently developed algorithms for selection of Zernike terms in customized treatments for refractive surgery were used. Clinical outcomes and tissue-saving attributes were evaluated on 2 groups [minimize depth (MD) and minimize volume (MV); 30 eyes each], plus a control group [corneal wavefront (CW); 30 eyes] with conventional customized approach. Clinical outcomes were evaluated in terms of predictability, safety, and contrast sensitivity and tissue-saving attributes in terms of saved depth and time for each condition (in micrometers, seconds, and percentage) and whether minimized depth or time were less than required for equivalent noncustomized treatments.


RESULTS
Ninety-three percent of treatments in the CW group, 93% in the MD group, and 100% in the MV group were within 0.50 diopters of spherical equivalent (SEq) postoperatively. Forty percent of treatments in the CW group, 34% in the MD group, and 47% in the MV group gained at least 1 line of best spectacle-corrected visual acuity postoperatively. Tissue-saving attributes showed an average saved depth of 8 μm (1-20 μm) and a saved time of 6 seconds (1-15 seconds) in the MD group and 6 μm (0-20 μm) and 8 seconds (2-26 seconds) in the MV group. Proposed corrections were always less deep and shorter than full wavefront corrections. In 43% of the MD cases, corrections were less deep, and in 40% of the MV cases, corrections were shorter than equivalent aberration-free treatments.


CONCLUSIONS
The minimization techniques compared here effectively reduced depth and time needed for ablation (up to a maximum of 50% and by 15% in average) without negatively affecting clinical outcomes postoperatively, yielding results equivalent to those of the full customization group.
Arba-Mosquera
Samuel
S
Instituto de Oftalmobiología Aplicada, University of Valladolid, Valladolid, Spain. samuel.arba.mosquera@eye-tech.net
Arbelaez
Maria Clara
MC
Merayo-Llovés
Jesús
J
D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000517:prevention & control; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D013997:Time Factors; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult