Posters

Comparative analysis of visual outcomes following small incision lenticule extraction with or without cyclotorsion compensation in eyes with high astigmatism and intraoperative cyclotorsion: contralateral eye study

Poster Details

First Author: S.Ramamurthy INDIA

Co Author(s):    G. Sachdev                    

Abstract Details

Purpose:

Intraoperative cyclotorsion of greater than 2 degrees if left uncorrected, can cause under correction and induction of aberrations especially in high astigmatism. The VisuMax femtosecond laser system (Carl Zeiss, Meditech, AG) provides no technical support for cyclotorsion compensation in Small Incision Lenticule Extraction (SMILE). The purpose of the study was to comparatively evaluate visual outcomes following SMILE with or without manual cyclotorsion compensation in eyes with high myopic astigmatism (1.5 Diopters or greater) and intraoperative cyclotorsion (5 degrees or greater)

Setting:

A tertiary eye care hospital in South India

Methods:

The study adhered to the tenets of Declaration of Helsinki, an ethics committee approval was obtained and an informed consent was taken from all patients. This prospective, interventional contralateral study included patients with bilateral high myopic astigmatism (1.5D or greater) and intraoperative cyclotorsion (5 degrees or more). Cyclotorsion compensation was performed using triple centration method prior to femtosecond laser delivery. Visual acuity measurement, manifest refraction, slit lamp bio microscopy and corneal tomography were performed preoperatively and at 1 and 3 months’ postoperative visit. Astigmatic outcomes were analyzed using Alpins criteria.

Results:

This prospective, interventional contralateral study included 60 eyes of 30 patients with a median age (IQR) of 22.5(20,29). The median (IQR) preoperative astigmatism and intraoperative cyclotorsion was -2D (-2.75, -1.5) and 7.03 ± 1.06 degrees in the cyclotorsion compensation group (CC), and -1.75D (-2.5, -1.5) and 7.24 ± 0.98 degrees in the non cyclotorsion compensation (NC) group (P=0.47,0.24). No significant difference in postoperative cylinder, MRSE and UDVA was noted at 3 months between the two groups (P=0.19,0.29,0.71). Correction Index of 1.02 ± 0.19 and 1.01 ± 0.18 (P=0.803) was demonstrated.

Conclusions:

No significant difference was noted between the manual cyclotorsion compensation and no cyclotorsion compensation group vis-à-vis astigmatic correction and visual outcomes. A mean absolute error of 2.8° (range 3.8 to 6°) with conventional manual marking may be a possible limitation. Future studies demonstrating outcomes with inbuilt methods of cyclotorsion compensation may be the next step forward.

Financial Disclosure:

None