Session Title: Refractive
Session Date/Time: Sunday 17/02/2013 | 08:30-11:00
Paper Time: 10:10
Venue: Hall 3
First Author: : M.Bohac CROATIA
Co Author(s): : N. Gabric A. Biscevic
Purpose:
To evaluate safety and efficacy of LASIK enhancements.
Setting:
University Eye Hospital Svjetlost, Zagreb, Croatia.
Methods:
28 eyes (19 patients) underwent LASIK enhancement in a period from January 2011 to March 2012. The enhancements were performed 3 months to 10 years after the previous LASIK procedure. Follow up was 6 months. All patients underwent flap lifting and optimized ablation on Wavelight Eye Q 400Hz excimer laser.
We measured preoperative and postoperative uncorrected (UCVA) and best corrected (BCVA) visual acuity (Snellen lines), amount of high order aberrations, flap thickness (Anterior Visante OCT, Zeiss) and corneal tomography.
Results:
Preoperative UCVDA was 0,49±0,23 compared to 0,88±0,27 postoperative, preoperative BCVDA was 0,92±0,08 compared to 0,96±0,10 postoperative. Mean preoperative sphere was -0,32±1,02 (ranging from -2,00 to +2,00), mean preoperative cylinder was -0,52±1,86 (ranging from -4,00 to +2,25). Mean postoperative sphere was 0,20±0,55 (ranging from -0,75 to +1,50), mean postoperative cylinder was -0,23±1,01 (ranging from -2,25 to +2,25). There were no statistically significant differences according to two-tailed student t-test between preoperative BCDVA and postoperative UCDVA (p=0,501), there was also no statistically significant difference between preoperative and postoperative BCDVA (p= 0,115). Efficacy index at 6 months postoperative was 1,02, and safety index was 1,04. According to two tailed student t-test there was no statistically significant difference in high order aberrations measured at 3 and 5mm pupil – for coma p=0,299 form 3mm pupil and p=0,191 for 5mm pupil, for trefoil p= 0,181 and p=0,055, for spherical aberration p=0,842 and p=0,626 respectively. There were statistically significant differences in RMS at 3 and 5mm pupil (p=0,0053 and p=0,0078). All tomography data were unremarkable with central prior ablations. Corneal thickness at the thinnest point preoperatively was 515±47µm. Mean flap thickness was 101±45µm.
Conclusions:
LASIK enhancements are safe and effective. Optimized ablations provide predictable and repeatable results in a case of residual refractive errors and well centered ablations. In the case of decentered ablations or high amounts of higher order aberrations custom treatments are more suitable. Mechanical microkeratome flaps can be easily lifted even 10 years after the previous surgery.
Financial Disclosure:
None
