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Clinical study to evaluate the correlation of opaque bubble layer with corneal biomechanics and densitometry in eyes undergoing smile for myopic correction

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First Author: S.Reddy INDIA

Co Author(s):    S. Brar   S. Ganesh                 

Abstract Details

Purpose:

To evaluate the correlation of OBL with corneal biomechanics and densitometry in eyes undergoing SMILE for myopic correction

Setting:

Nethradhama superspeciality eye hospital, Bangalore

Methods:

All eligible patients underwent CORVIS ST and Pentacam HR OCULUS. Intraoperatively, following laser delivery OBL pattern was graded by the surgeon using semi-transparent overlay with multiple zones. Also, ease of dissection was graded after lenticule removal. Corvis biomechanical index (CBI), Tomographic biomechanical index (TBI), densitometry values were correlated with OBL. Pearson correlations were found and their significance was tested.

Results:

In this prospective study we evaluated 200 eyes of 200 patients, mean age of patients and spherical equivalent was 25.83±4.65 and -3.99±2.63 respectively. The average CBI, TBI, densitometry, OBL and ease of dissection was found to be 0.27+/- 0.24, 0.08+/- 0.10, 15.44+/- 1.64, 23.12+/- 7.19, 3.02+/- 0.34 respectively. Thinnest pachymetry before and after surgery was found to be 538.87+/- 34.65 and 479.31 +/- 39.49 respectively. Average Objective scatter index (OSI) post operatively was 0.88+/-0.46. We found a negative correlation of OBL with CBI and TBI which was statistically significant (p<0.05). Also, a statistically significant positive correlation of OBL with pre-operative pachymetry, densitometry and post-operative OSI score was inferred.

Conclusions:

Occurrence of OBL could be influenced by various factors like CBI, TBI, pachymetry and densitometry. A positive correlation of OBL with pachymetry, densitometry and post-op OSI indicates higher OBL percentages in denser cornea which in turn affects post-operative visual recovery. Hence a new nomogram for energy settings can be derived based on corneal stiffness and biomechanics for SMILE.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a competing company