ESCRS - PP27.04 - Predictability Of The Achieved Lenticule Thickness In Smart Sight Lenticule Extraction For Myopia Correction

Predictability Of The Achieved Lenticule Thickness In Smart Sight Lenticule Extraction For Myopia Correction

Published 2023 - 41st Congress of the ESCRS

Reference: PP27.04 | Type: Free paper | DOI: 10.82333/5f1d-c825

Authors: Maja Bohač* 1 , Ivan Gabric 1 , Mateja Jagic 1 , Krešimir Gabrić 1 , Samuel Arba Mosquera 2

1Eye Clinic Svjetlost,Zagreb,Croatia, 2SCHWIND eye-tech-solution,Kleinosteim,Germany

Purpose

This study aimed to investigate the predictability between the SCHWIND ATOS readout and achieved lenticule thickness measured using the MS-39 AS-OCT at corneal vertex at postoperative day 1, 1 and 3 months of follow-up.

Setting

Eye Hospital Svjetlost, School of Medicine University of Rijeka, Zagreb, Croatia

Methods

This case series of patients were treated at Specialty Eye Hospital Svjetlost in Zagreb, Croatia. 130 eyes of 65 consecutive patients were treated with SmartSight lenticule extraction were assessed. 64% of patients were female with a mean spherical refraction -4.98±1.19D and mean astigmatism of 0.53±0.64D. The measurements of flap and cap thickness was performed using AS-OCT on MS39 (CSO, Scandicci, Italy) using the Pheonix Software v 4.1.1.5.. The tool uses high resolution images in 9 sections of the cornea where the user identifies the cap interface and marks it for calculation.

Results

A lower reduction in CCT compared to laser read-out for all 3 follow-ups can be observed. Essentially, the reduction in CCT is identical at 3 months vs 1 month follow up. The reduction in CCT is lowest at postoperative day 1. Taking the 1M and 3M data (essentially equivalent) one can see a best fit of y=0.94x-7µm; i.e. a -6% plus a -7µm reduction.

Conclusions

The difference reduction in CCT vs laser read-out CANNOT be at all explained from the SC, OZ, TZ values or by the M, J0, J45 values (neither signed nor in absolute value); only the -7µm remain statistically significant (isolated without any other explanator). Yet, the difference reduction in CCT vs laser read-out CAN be explained from these “foreign” values:

  • larger Spot Distance meaning less apparent undersize in thickness
  • larger Track Distance meaning less apparent undersize in thickness
  • higher Treatment Dose meaning less apparent undersize in thickness
  • higher Laser Power meaning MORE apparent undersize in thickness

Although the explanators only account for 1µm or 1%, and the other -6µm and -6% remain as isolated term