Refractive And Visual Outcomes After Corneal Lenticule Extraction For Advanced Refractive Correction (Clear) Of Three Surgeons Following The Same Standardized Surgical Protocol.

To compare the refractive and visual outcomes between three surgeons following a standardized surgical protocol for CLEAR surgery.

A retrospective, single-site, comparative consecutive case series study. All patients were treated with CLEAR at the Central Seoul Eye Center in Seoul, Republic of Korea.

86 eyes (43 patients) with mean preoperative sphere of −3.58 ± 1.12 diopters (D) (range: -2.00 to -6.50 D) and cylinder of −0.89 ± 0.75 D (range: -0.25 to -3.50 D) underwent CLEAR surgery performed by three surgeons (KHK, YAR and KMJ) following the most updated standardized surgical protocol using the FEMTO LDV Z8 laser (Ziemer Ophthalmic Systems AG). KHK operated 40 eyes and YAR and KMJ operated 26 eyes and 20 eyes, respectively. Postoperative manifest sphere, cylinder, spherical equivalent (SE), uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed at 1 week and 1 month after the surgery and compared among the 3 surgeons for statistical differences.

There was no statistically significant difference in UDVA, CDVA and postoperative manifest cylinder among surgeons at any of the postoperative follow-up visit (one-way ANOVA analysis). Preoperatively, the mean SEs were -3.75 ± 0.98 D, -4.28 ± 1.27 D and -4.07 ± 1.18 D, whilst the mean cylinders were -1.27 ± 0.90 D, -1.05 ± 0.75 D and -0.56 ± 0.42 D for YAR, KMJ and KHK, respectively. 1 month after the surgery, CLEAR showed high refractive accuracy with a SE of ±0.25 D in 75% (YAR), 68% (KMJ) and 69% (KHK) of eyes and ±0.50 D in 100%, 100% and 91% of eyes. High accuracy of astigmatism correction in low to high degrees of myopic astigmatism was also observed, with the mean cylinder reduced to -0.19 ± 0.31 D, -0.33 ± 0.29 D and -0.13 ± 0.23 D.

Use of a standardized surgical protocol during CLEAR procedure provided equivalency in visual outcomes and high accuracy in both refraction and astigmatism correction among surgeons. The precision in the refractive correction could be explained by the use of a nomogram based on Korean patient population, while the high accuracy of the astigmatism correction was due to lenticule centration on the visual axis and cyclotorsion compensation by marking the cornea using an image-guided system. In order to achieve good visual outcomes, among others factors, the standardized surgical protocol prioritized laser power optimization as a function of smooth lenticule dissection, at minimal gas bubble formation.