Comparison Of The Accuracy Of Residual Corneal Stroma Calculation By Performing Relex Smile And Femto-Lasik.
Published 2024
- 42nd Congress of the ESCRS
Reference: PP03.15
| Type: Free paper
| DOI:
10.82333/b4a6-3x61
Authors:
Kateryna Kostrovska* 1
, Tetyana Zavgorodnya 2
, Iryna Poplavska 2
, Nadiia Kryvobok 2
, Oleksandr Kostrovskyi 3
1Department 1,LLC "Visus",Zaporizhzhia,Ukraine;Department of Ophthalmology,Zaporizhzhia State Medical and Pharmaceutical University,Zaporizhzhia,Ukraine, 2Department 1,LLC "Visus",Zaporizhzhia,Ukraine, 3Department of Ophthalmology,Zaporizhzhia State Medical and Pharmaceutical University,Zaporizhzhia,Ukraine
Purpose
Comparison of the actual postoperative corneal thickness in patients with moderate and high myopia who underwent ReLEx SMILE and FEMTO-LASIK with the calculated values.
Setting
This retrospective study was conducted at the Department of Ophthalmology, Zaporizhzhia State Medical and Pharmaceutical University, and the LCC "Visus" Medical Center, Zaporizhzhia, Ukraine.
Methods
This retrospective study included 64 myopic eyes of 32 patients aged 20 to 37 years. The eyes were divided into two groups: performed FEMTO-LASIK (group 1) and performed ReLEx SMILE (group 2) (26 eyes and 38 eyes, respectively).
Femtosecond procedures were performed on the VisuMax 500, Carl Zeiss, and excimer interventions on the WaveLight EX500, Alcon.
Corneal Thickness (CT) was assessed by anterior segment optical coherence tomography (OCT) (Visant OCT, Carl Zeiss) before and after surgery. The difference between the calculated CT according to the laser data and the actual CT according to the OCT data was calculated on the 1st day after surgery. The measurements between the groups were compared using the Mann-Whitney test.
Results
There were no statistically significant differences in age, sex, and preoperative and postoperative CT between the groups (p > 0.05).
The median values of the difference between the calculated and actual CT after surgery were 8 [-7; 20] μm and 17 [7; 25] μm, respectively, after FEMTO-LASIK and after ReLEx SMILE (p < 0.05), which was almost 2 times higher.
In the ReLEx SMILE group, there were no eyes with a calculated CT greater than the actual one after surgery, while in the FEMTO-LASIK group, there were such eyes.
Conclusions
Statistically significant differences of almost 2 times were found in the difference between the calculated and actual CT in patients with high and moderate myopia after FEMTO-LASIK and after ReLEx SMILE. After ReLEx SMILE, the postoperative CT was never less than the calculated value. With critical residual CT parameters, there is no advantage to performing FEMTO-LASIK. Although the calculated thickness of the ReLEx SMILE correction is always greater by the lenticule step height than with FEMTO-LASIK, after performing FEMTO-LASIK the actual CT may be less than the calculated one, therefore an additional stromal reserve should be left.