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AIM: To observe the epithelial remodeling of femtosecond laser-assisted stromal lenticule addition keratoplasty combined with corneal collagen cross-linking(SLAK-CXL)in patients with progressive keratoconus, investigate the remodeling rules of corneal epithelial and influencing factors, and provide clinical data for further refractive correction.METHODS: Retrospective and observational study. A total of 28 keratoconus patients(29 eyes)who received SLAK-CXL from September 2020 to October 2021 were included. Preoperative and postoperative visual acuity, intraocular pressure(IOP), diopter, keratometry and corneal epithelial thickness(CET)were recorded. The trend of CET change was observed. The factors affecting CET were analyzed according to the thickness and depth of the lenticule.RESULTS: Flattest meridian keratometry(Kf)and steepest meridian keratometry(Ks)at 1mo postoperatively were significantly larger than those preoperatively(P0.05).CONCLUSIONS: It is firstly found that the corneal morphology has changed after SLAK-CXL. CET decreases and then increases and then decreases again. At 1a postoperatively, the CET of the central and paracentral areas is thinner, while the CET of the midperipheral and peripheral areas is thicker. The degree of epithelial remodeling is not correlated with lenticule thickness or depth.

As the prevalence of myopia continues to increase, our society shows increasing interest in the visual impairment associated with myopia and methods for myopia control. Current methods for myopia control include atropine, orthokeratology, dual-focus contact lenses, multifocal contact lenses, and functional frame glasses, etc. Low-concentration atropine(0.01%, 0.05%)became the first-line medication which has been administrated and shown to be effective in controlling the occurrence and progression of myopia. Meanwhile, low-concentration atropine shows longer-lasting effects, less frequent adverse effects and higher patients' acceptance than high-concentration atropine. This article reviews the efficacy, safety, time-to-treatment, and effects when combined with other treatments to provide evidence for the clinical application of low-concentration atropine on myopia control.

AIM: To compare the change of refractive power and corneal high-order aberrations after femtosecond laser-assisted excimer laser in situ keratomileusis(FS-LASIK)and FS-LASIK combined with accelerated corneal cross-linking(FS-LASIK Xtra)for high myopia correction, and to evaluate the early effects of two surgical methods to correct high myopia. METHODS:Retrospective case-control study. Totally 42 patients(84 eyes)with high myopia underwent FS-LASIK Xtra and FS-LASIK in our hospital from April 2019 to April 2020 were followed up for 3mo, including 21 patients in each group(42 eyes). The uncorrected visual acuity(UCVA), spherical equivalent(SE), astigmatism and corneal high-order aberration of the two groups were analyzed and compared.RESULTS: The UCVA of the FS-LASIK Xtra group was significantly lower than that of the FS-LASIK group at 1d after surgery(P0.05). The postoperative SE of the two groups was significantly lower than that before surgery, at 3mo after surgery, 38 eyes(90%)in the FS-LASIK Xtra group and 41 eyes(98%)in the FS-LASIK group had SE within ±1.00D. In both groups, 35 eyes(83%)had residual astigmatism within 0.50D after surgery. The total corneal high-order aberrations, spherical aberrations, coma and clover aberrations in the two groups were increased at 3mo after surgery, the total high-order aberration and clover aberration in the FS-LASIK Xtra group were greater than those in the FS-LASIK group(all P

AIM:To analyze satisfaction on night vision and its related factors after FS-LASIK in patients with high and low-to-moderate myopia.METHODS:This was a retrospective study. Totally 75 patients(150 eyes)who underwent FS-LASIK in Xi'an No.1 Hospital from June 2018 to September 2019 were included. All subjects were divided into two groups based on spherical equivalent(SE): high myopia group(SE≥-6.00D)and low-to-moderate myopia group(0.05)between the two groups. Overall satisfaction was 95.3% and 100.0% in high and low-to-moderate myopia group. 18.8% and 9.3% experienced worsen night vision, 51.2% and 40.6% experienced halo, 41.9% and 43.8% experienced starburst, and 18.6% and 15.6% experienced double vision, respectively. Except that there was significant differences in night vision between the two groups(P=0.010), the occurrence of other night vision symptoms were similar and there were no significant differences in any of them(all P>0.05). For all patients, the satisfaction was correlated with preoperative astigmatism and ablation zone(all P

AIM: To investigate differences between 6.0mm and 6.5mm optical zones in visual quality after FS-LASIK. METHODS: This was a prospective study. Totally 25 patients(50 eyes)treated with FS-LASIK were included and they were classified into 6.0mm group and 6.5mm group according to optical zone. Objective visual quality was evaluated by OQASⅡoptical quality analysis system(including OSI, Strel Ratio, MTF cut off, OV100%, OV20%, OV9%)and by Sirius to obtain the higher order aberrations parameters(including total HOAs, spherical aberrations, trefoil and coma)at 3mm, 5mm and 7mm pupil sizes. OSDI questionnaire was applied to evaluate patients' subjective visual quality. RESULTS: At 3mo postoperatively, there were no significant differences in total HOAs, spherical aberrations, trefoil and coma under 3mm pupil size(all P>0.05). Significant differences were only observed in spherical aberrations at 5mm pupil size(PPP>0.05).CONCLUSION: HOAs under scotopic conditions could be less with 6.5mm optic zone after FS-LASIK, however, both 6.0mm and 6.5mm optical zones could achieve good subjective and objective visual quality after FS-LASIK.

AIM: To investigate the related factors of orthokeraology(ortho-K)decentration.METHODS: Within a prospective study, 88 eyes of 88 patients who visited to our center between July 2014 and December 2016 were enrolled. To verify the possible role of the spherical equivalent(SE), the corneal astigmatism(CA), e value, steep K, flat K, front curvature asymmetry index(SIf)and age in the ortho-K location prediction.RESULTS: This study included 24 eyes of grade Ⅰ decentration, 26 eyes with grade Ⅱ, 25 eyes with grade Ⅲ, and 13 eyes with grade Ⅳ, by which based on the decentration system that published by our team. One-way ANOVA showed that there was statically significant difference of SE, Ks and Kf in different grading groups(PPCONCLUSION: The SE might be the main factor which lead to the ortho-K decentration.

AIM:To investigate the changes in anterior segment parameters by Sirius anterior system after orthokeratology and the possible mechanisms. METHODS: Twenty-eight patients(56 eyes)with myopia in our hospital from August 2014 to October 2014 were included. Spherical equivalent were -3.83±1.19D. Data of central corneal thickness(CCT), anterior chamber depth(ACD), anterior corneal curvature(a-K)and posterior corneal curvature(p-K)were collected and analyzed at before, 1d, 1wk and 3mo after orthokeratology.RESULTS: After orthokeratology, spherical equivalent of all eyes decreased to predicted level. There were no significant differences in CCT and p-K between different times(P>0.05). There were significant differences in a-K between different times except between 1wk and 3mo after orthokeratology(PPPP=0.016), a-Kc-1wk(P=0.047)were correlated with a-Kpre and axial, respectively. And there were correlations between a-Kpre and a-Kc-3mo(P=0.024), between ACDpre and ACDc-1d(P=0.036), between CCTpre and CCTc-3mo(P=0.012), respectively.CONCLUSION: CCT, ACD and p-K has no significant changes after orthokeratology, while there is significant difference in a-K, which is considered one of the most key factor in orthokeratology. Sirius anterior system for examination before orthokeratology and postoperative assessment, non-invasive, reliable and has a good clinical value.

AIM:To observe the effect of posterior chamber phakic intraocular lens implantation for high myopia on the stereopsis. To evaluate the implantation of implantable contact lens from the highest form of visual angle. METHODS:Fourty-six patients(92 eyes)with high myopia were included from January to December 2014. The average age of patients was 26.13±3.37(19～32)years, and 20 males(43%)and 26 females(57%)were observed. Analysis the stereopsis of these patients before and after the implantation of posterior chamber phakic intraocular lens. RESULTS:The mean spherical equivalent of all the eyes was 10.02±2.71D before and -0.02±0.25D after surgeries. There was significant difference on the spherical equivalent(t=14.062, P=0.000).There were 6 patients with the blind of near stereopsis, the near stereopsis of the rest patients were 637.50±462.08arcsec before the surgeries and there were none with the blind of near stereopsis after surgeries. The near stereopsis of all the patients were 126.09±165.78arcsec after surgeries. There were 12 patients with the blind of far stereopsis, the far stereopsis of the rest patients were 400.59±257.00arcsec before the surgeries. After surgeries there were 2 patients with the blind of far stereopsis, the far stereopsis of the rest patients were 152.73±111.65arcsec. There were both significant differences on the near stereopsis(Z=-5.725, P=0.000)and the far stereopsis(Z=-4.976,P=0.000)before and after surgeries.CONCLUSION:Posterior chamber phakic intraocular lens implantation not only correct the ametropic of the high myopia, but also improve the visual acuity and the stereopsis.