Sequential Smile Xtra-Is Taking An Extra Mile Beneficial?
Published 2023 - 41st Congress of the ESCRS
Reference: PP14.09 | Type: Free paper | DOI: 10.82333/tdgs-k539
Authors: Anisha Ramesh* 1 , Rohit Shetty 2 , Pooja Khamar 2 , Abhijit Sinha Roy 3 , Raghav Narasimhan 1 , Rahul Patil 3
1Narayana Nethralaya,Bangalore,India, 2Cornea & Refractive services,Narayana Nethralaya,Bangalore,India, 3GROW lab,Narayana Nethralaya,Bangalore,India
Purpose
To assess phase retardation and corneal fibril orientation using ultrahigh resolution polarization-sensitive OCT (PS-OCT) in Small incision Lenticule Extraction (SMILE) vs post SMILE XTRA in patients with suspicious topography.
Setting
Tertiary Eye Care Hospital in Southern India
Methods
20 eyes of 10 patients were enrolled in this study based on refraction, borderline topography, weak biomechanics, epithelial and stromal imaging. All the patients were evaluated using Pentacam, Corvis ST, MS-39 and custom-built polarisation sensitive optical coherence tomography (PS-OCT). SMILE surgery was performed on all 20 eyes on Visumax 500. Xtra procedure was done after one month by instilling 0.23% riboflavin for 3 minutes followed by 45 mW/cm2 UVA irradiation for 90 seconds. Since the xtra procedure was done after 1 month of SMILE surgery, we called it as Sequential SMILE Xtra. Patients were followed up at 1 week,1,3 and 6 months to asses for stability by pentacam, MS-39, Corvis-ST, collagen orientation & phase retardation by PSOCT.
Results
The phase retardation en face maps of pre-op scans showed preferential distribution of collagen with least retardation in apex and maximum retardation in the periphery. Post SMILE surgery scans showed altered PR as compared to normal healthy eye. However, after Xtra procedure, PR was found to regain its preferential arrangement as compared to the pre-op normal cornea. The collagen fibril orientation on the other hand also proved the impact of Xtra procedures in strengthening the weak corneas.
Conclusions
To conclude, Sequential SMILE Xtra was proved to be a reliable laser vision correction procedure in patients with suspicious topography or weaker corneas as shown by improvement in the collagen fibril orientation and PR maps in post xtra eyes. This implies that combining sequential xtra procedure with SMILE will provide biomechanical stability to the weaker suspect corneas.