The Impact Of Binocular Functions On Cyclotorsion Error Correction In Lenticule Extraction With The Smile Pro Technique In Patients With Astigmatism.
Published 2025 - 43rd Congress of the ESCRS
Reference: PO712 | Type: Free paper | DOI: 10.82333/kt0k-ey82
Authors: Shawn Sapir* 1 , Michael Mimouni 2 , Tzahi Sela 3 , Gur Manzur 3 , Igor Kaiserman 4
1Barzilai Univeristy Medical Center ,Ashkelon,Israel;Barzilai University Medical Center,Ashkelon,Israel, 2Rambam Medical Center,Haifa,Israel, 3Care Laser vision center ,Tel-Aviv,Israel, 4Barzilai University Medical Center,Tel-Aviv,Israel
Purpose
To measure cyclotorsion parameters in patients with binocular vision impairment and compare them with a control group of healthy individuals with normal binocular vision after undergoing laser correction using the SMILE Pro technique. This analysis allows for assessing the impact of position-induced cyclotorsion on astigmatism correction in refractive surgery.
Setting
Doctor Shilova’s Clinic
Methods
This was a comparative observational study analyzing the outcomes of 60 patients (120 eyes) who underwent SMILE Pro correction. Among them, 28 patients lacked binocular vision, while 32 had normal binocular vision. Regarding gender distribution, 37.5% were male and 62.5% were female. The age range was 20 to 54 years, with a median of 29 years. The lowest degree of astigmatism recorded was -0.75 diopters cylinder (DC), while the highest was -5.0 DC, with an average value of -3.06 ± 1.16 DC. Incyclotorsion was denoted by a negative sign (-), and excyclotorsion by a positive sign (+).
Results
In the first group, the maximum excyclotorsion recorded was +8.7 degrees, while the maximum incyclotorsion was -10.0 degrees. The mean torsion (either excyclo- or incyclotorsion) was 4.74 (88.7%) with a standard deviation of 3.30 degrees. No statistically significant difference (p=0.985) was found in cyclotorsion values between patients with mild and high astigmatism.
In the second group, the maximum excyclotorsion recorded was +3.1 degrees, while the maximum incyclotorsion was -2.0 degrees. The mean torsion was 1.74 (65.3%) with a standard deviation of 1.20 degrees. Cyclotorsion values were higher in patients with more severe astigmatism.
Conclusions
Cycloposition of the eyes remains relatively stable in individuals with binocular vision; however, clinically significant effects may be observed in cases of high astigmatism (greater than 2.5D). For patients lacking binocular function, even a minor degree of astigmatism (0.75D) can impact the final refractive outcome if cyclotorsion compensation is not applied.
This finding suggests that for patients with impaired binocular function, lenticular correction with automatic or semi-automatic cyclotorsion compensation (SMILE Pro/SmartSight) is recommended in refractive surgery.