Recent advances in small incision lenticule extraction(SMILE)-derived refractive lenticule preservation and clinical reuse

Small incision lenticule extraction(SMILE)has become one of the mainstream refractive surgeries in recent years,with satisfactory efficacy,safety,and predictability.SMILE-derived refractive lenticule,the byproduct of the surgery,holds great potential in clinical practice given its easy access and good biocompatibility.Numerous studies have been published to describe its applications in refractive correction,corneal ectasia diseases,and corneal defects.The feasibility and safety were validated in both animal models and clinical studies.Moreover,the preservation method is also crucial for its further promotion and application.Novel techniques are also evaluated and applied in lenticule preservation.We covered the recent advances in the preservation of corneal stromal lenticules and their clinical reuse in this review.

Femtosecond laser corneal refractive surgery for the correction of high myopic anisometropic amblyopia in juveniles

AIM： To evaluate the effects of femtosecond laser-assisted in situ keratomileusis（FS-LASIK） and small-incision lenticule extraction（SMILE） to correct high myopic anisometropic amblyopia in juvenile patients. METHODS： From November 2013 to January 2015, 33 amblyopic patients with high myopic anisometropic amblyopia were studied. FS-LASIK（30 eyes） or SMILE（3 eyes） was performed in the amblyopic eyes. Visual acuity, refraction, contrast sensitivity, stereoacuity and complications were evaluated. Patients completed followup examinations at 3 d, 1 mo, 3 mo and the last follow-up time（mean 8.17±3.23 mo） after surgery. RESULTS： The mean age at surgery was 9.04±3.04 y（range 6-16 y）. The mean spherical equivalent in the amblyopic eyes was significantly decreased from-10.00±2.39 D preoperatively to-0.06±1.06 D at 1 mo,-0.19±1.33 D at 3 mo and-0.60±1.43 D at approximately 8 mo postoperatively（P〈0.05 for all）. The mean myopic anisometropia was significantly decreased from-9.45±2.33 D preoperatively to ＋0.37±1.48 D at 1 mo,-0.46±1.47 D at 3 mo and-0.09±1.83 D at approximately 8 mo（P〈0.05 for all）. The logarithm of the minimum angle of resolution（log MAR） for uncorrected and corrected distance visual acuity（UDVA and CDVA, respectively） of the amblyopic eye improved from 1.74±0.35 and 0.98±0.63 preoperatively to 0.45±0.31 and 0.41±0.33 at approximately 8 mo after surgery, respectively. The logM AR CDVA at 3 d, 1, 3 and 8 mo postoperatively improved by means of 1.42, 2.22, 2.96, and 4.39 lines, and a gain of more than two lines accounted for 45%, 50%, 74% and 86% of all patients, respectively. The contrast sensitivity of both amblyopic eyes and dominant eyes at 0.5, 2, 8 cycles perdegree was significantly improved postoperatively（P〈0.05 for all）. Of the 33 pediatric patients, no patients had near stereopsis preoperatively and seven patients（21.2%） recovered near stereopsis（400″ to 60″） at approximately 8 mo after surgery. No intraoperative or postoperative complications occurred in any patient.CONCLUSION： FS-LASIK or SMILE can be promising alternative methods to correct high myopic anisometropic amblyopia in juvenile patients who have failed with traditional approaches.

Postoperative changes in corneal epithelial and stromal thickness profiles after SMILE in high myopic eyes

Background:To observe changes in the epithelial and stromal thickness after small incision refractive lenticule extraction(SMILE)and investigate their relationship with the different refractive error.Methods:One hundred and eighty eyes of 90 patients with a manifest refraction spherical equivalent(MRSE)of-6.36±1.53 diopters(D)were included.The eyes were assigned to the moderate myopic group(MRSE-3.00 to-6.00 D),high myopic group(MRSE-6.00 to-8.00 D)and super-high myopic group(MRSE above-8.00 D).The spectral-domain optical coherence tomography(SD-OCT)measured corneal and epithelial thickness in 17 zones preoperatively and 1,3,and 6 months postoperatively.Stromal thickness was calculated by subtracting the epithelial thickness from the total corneal thickness.The observed changes were correlated with the degree of myopia corrected.Results:MRSE showed significant differences between 3 and 6 months in the super-high myopic group(P=0.024).At 6 months,a statistically significant epithelial thickness increase was observed in the central zone(7.18%for moderate,10.23%for high,and 13.76%for super-high myopia,P<0.05 for all groups).The peripheral thickness decreased between 3 and 6 months in the high myopia and super-high myopia groups(P<0.05,respectively).A positive correlation between MRSE corrected and the postoperative epithelial thickening was observed in the central(r2=0.551,P<0.05).Compared to 1 month values,the central stromal thickness showed a decrease(3.2±4.5μm)at 3 months and an increase(4.4±4.9μm)at 6 months.The stroma thickened in moderate and high myopic groups but the thickness reduction were in super-high myopia group at 6 months paracentrally and peripherally.Conclusions:Significant thickness changes in the epithelium and stroma were detected during the 6 months after SMILE.Preliminary results suggest that epithelial and stromal thickness profile changes after SMILE may have an impact on the refractive outcome in the long-term postoperative period,especially in super-higher degrees of myopia.

A Novel Tectonic Keratoplasty with Femtosecond Laser ntrastromal Lenticule for Corneal Ulcer and Perforation

Background： Small incision refractive lenticule extraction （SMILE） is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule （TEKIL）. Methods： A total of twenty patients （22 eyes） were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity （BCVA）. Postoperative complications throughout the study period were recorded. Results： Corneal ulcer in 14 patients （16 eyes） and corneal perforation in six patients （6 eyes） were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years （range： 16 81 years）. In this study, the most causes of corneal ulcer or perforation were immunologic causes （54.5%）. After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up （t = 2.095, P 0.052）. The postoperative BCVA improved in 12 eyes （54.5%） and maintained in nine eyes （40.9%）. Vision function successfully maintained in all eyes （100%）. In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months alter the initial surgery for the reason that the residual corneal thickness was 〈250 μm. Conclusions： TEKI L seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage.