Evaluation of Percentage Tissue Ablated of 2 Cap Thicknesses in Small-Incision Lenticule Extraction and Keratectasia
A percentage tissue ablated (PTA) of more than 40% was suggested a negative prognostic factor for keratectasia after LASIK surgery. This quality management investigation addresses the question, whether keratectasia occurred in different PTA in SMILE surgery with a residual cap of 140 and 130 µm.
So far the results of 400 eyes are evaluated over up to 36 month after SMILE treatment. Calculated PTA was compared to keratectasia development assesed with Scheimpflug tomography, videokeratography and aberrometry readings at each follow up visit over 36 month.
No signs of keratectasia were found in all 400 patients in PTA ranging from 34%-52%.
So far our results show a low risk for keratectasia development. Still future studies are needed to show whether or not the SMILE technique will push the PTA limit to higher values without the risk of keratectasia.