Safety And Efficacy Of Corneal Lenticule Extraction For Advanced Refractive Correction (Clear) In Patients With Concurrent High Myopia And High Astigmatism.

to assess safety and efficacy of Corneal Lenticule Extraction for Advanced Refractive Correction (CLEAR) in patients with more than 5 dioptres (D) of myopia and more than 2 D of astigmatism.

Centre for Research in Refractive Surgery (Poggibonsi, Italy).
Siena Eye Laser Refractive and Cataract Surgery Clinic (Poggibonsi, Italy). 

retrospective study of CLEAR procedures performed at Siena Eye Laser (Poggibonsi, Italy) using the FEMTO LDV femtosecond laser (Ziemer Ophthalmic Systems). Inclusion criteria were myopia greater than 5D, cylinder greater than 2D, corrected distance visual acuity (CDVA) greater than 0.2 logMAR, age 21 years or older, and suitable for CLEAR. Patients were evaluated at baseline, post-operative day 1 (POD1) , and six months.

we included 97 eyes of 54 patients with a mean age of 33.6±6.4years.At baseline mean myopic error was -7.0±1.2D,mean astigmatism error was -3.0±0.8D,and  mean spherical equivalent refractive error was -8.6±1.1D.Preoperative CDVA was 0.0 logMAR.Expected residual stroma thickness (RST) was 248.6±7.1microns with a mean expected percentage tissue altered (PTA) of 46.2±8.2 %.At POD1 uncorrected distance visual acuity (UCDVA) was 0.17±0.1logMAR,RST increased to 274.6±15.6 microns (p<0.001),and PTA decreased to 39.5±6.3% (p<0.001).At 6 months,UCDVA increased to 0.04±0.06 logMAR(p=0.002),with a mean myopic residual error of 0.25±0.5D,a mean cylinder residual error of 0.3±0.2D,and a residual SER of 0.2±0.3D.RST remained stable at 270.3±12.3(p>0.05).

In patients with concurrent high myopia and high astigmatism, CLEAR showed good predictability and efficacy. Despite the high SER treated, residual stromal thickness was higher than predicted values, confirming the safety of the procedure in these eyes.