Abstract
Purpose :
Cyclorotation (CR) has been studied and used in different excimer laser devices, in order to achieve optimal results with laser vision correction. However, no studies with the Wavelight® refractive suite have yet been published. The purpose of the study is to analyze the correlation between clinical findings and CR after iris registration with the Vario® software from the Topolyzer® topographer and its corrective compensation to the supine position before the treatment with wavefront-optimized femtosecond-assisted LASIK with the Wavelight EX 500®, in patients with myopia and myopic astigmatism.
Methods :
This retrospective chart-review study from January thru October 2017 included 90 eyes from 45 healthy subjects (28F/17M). Preoperative clinical data was obtained from electronic medical records. CR characteristics, pupil size and treatment data were taken from the excimer laser database.
CR, pupil size and refractive errors, in diopters (D) were analyzed with student t-test and Spearman rank-correlation in Stata.
Results :
The related means found were: age (35.85 ± 11.44 years); refractive spherical error (-4.15 ± -2.25 D); cylinder error (-0.61± -0.51 D); pupil size (6.23 ± 0.96 mm) and CR was -0.4 ± 3.9o. Comparing each patient's eyes, the mean CR was 0.66 ± 3.95o, 95% CI [-0.53, 1.84] in the right eye and -1.19 ± 4.0o, 95% CI [-2.39, 0.14], in the left eye (p<0.01).
Significant changes in CR were noted from diagnostic (sitted) to intraoperative (supine) position (p<0.01). From 90 eyes, 6 (6,6%) had no CR changes (value = 0o).
Weak negative correlation was found between: CR and pupil size (ρ=-0.0317, p>0.05); CR and pre-treatment spherical equivalent (ρ=-0.224, p>0.05); pre-treatment spherical equivalent and pupil size (ρ=-0.2185, p<0.05); CR and pre-treatment cylinder axis (ρ=-0.122, p>0.05); pre-treatment cylinder axis and pupil size (ρ=-0.0833, p>0.05) and weak positive correlation between pre-treatment cylinder and pre-treatment spherical equivalent (ρ=0.0602, p>0.05).
There was weak negative correlation between cyclorotation and eye dominance (ρ=-0.0851, p>0.05).
Conclusions :
CR of up to 10 degrees were noted when changing from sitting to supine position, with a significant difference between each patient’s eyes (left/right).
Weak correlation between the degree of CR and the clinical findings was found in patients with myopia and myopic astigmatism.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.