Since 2002， femtosecond lasers have been used for more than a decade to create laser in situ keratomileusis （LASIK） flaps. The equipment shifted from higher pulse energy and lower frequency to lower pulse energy and higher frequency. Compared to the traditional mechanical microkeratome， the femtosecond laser has its own advantages， such as a more precise and even corneal flap， no severe flap break during the operation， and the flap can be customized for shape， size and side cutting angle. The femtosecond laser can also perform corneal lenticule extraction for correcting myopia and astigmatism. Nevertheless， complications such as suction loss during the operation， an opaque bubble layer， a flap button hole and some visual problems after femtosecond laser-assisted LASIK should be of concern.

Femtosecond laser can make cuts with high safety and accuracy. This technology has played an increasingly important role in corneal refractive surgery. Recently， it has been largely applied in the creation of corneal flaps in laser in situ keratomileusis （LASIK）. Femtosecond laser has advantages in safety， predictability and biomechanical stability. Refractive lenticule extraction （ReLEx） represents the latest advance in corneal refractive surgery and is a promising procedure. Furthermore， several novel scanning procedures of the corneal stroma have been under study.

Objective  To investigate the effect of varying degree lenticule offset in small incision lenticule extraction （SMILE） for the correction of myopia and myopic astigmatism， and to evaluate the safety， efficacy， and predictability of the SMILE. Methods  In this prospective cohort study， 229 eyes of 115 patients underwent SMILE with VisuMax laser （Carl Zeiss）. The mean spherical equivalent （SE） was -2.25 to -9.75 D， with an average of -5.13±2.11 D， astigmatism was 0 to 4.25 D， with an average of 1.12±0.68 D. Based on the degree of lenticule center deviates from the standard center， patients were divided into group A （less than 80 µm）， group B （80 to 150 µm） and group C （more than 150 µm）. Uncorrected visual acuity （UCVA）， aberration and residual astigmatism after surgery were measured. Data were compared using a ANONA， K-WH test and corrected chi-square test. Results  There were no intraoperative and postoperative accidents and serious complications， and postoperative UCVA improved markedly. One day， 3 months postoperation the differences were statistically significant （x²=50.713， F=19.011， P<0.01）. The differences of residual astigmatism between the 3 groups 1 day and 3 months postoperation were significantly （x²=28.272， 34.721， P<0.01）. The anterior corneal surface coma and spherical aberration postoperative were increased. Group C had the most significant increase in coma （C7， C8）， followed by group B， group A minimum， the differences between the 3 groups were significant （x²=51.533， 49.804， P<0.01）. While the differences in the changes in spherical aberrations between the groups were not statistically significant （x²=2.794， P>0.05）. Conclusion  Attention to the accuracy of lens positioning can improve the effectiveness of surgery， and reduce the occurrence of postoperative astigmatism and coma.

Objective  To investigate changes in tear dynamics and corneal sub-basal nerve fiber regeneration after laser in situ keratomileusis （LASIK） surgery  with a femtosecond laser and a mechanical microkeratome. Methods  In a prospective case-control study， 40 eyes of 20 patients were treated with FEMTO LDV femtosecond laser LASIK surgery （F-LASIK group） or mechanical microkeratome LASIK surgery （M-LASIK group） respectively. Tear film break-up time （BUT）， Schirmer I test with corneal fluorescein staining （FS） and in vivo confocal microscopy of corneal subbasal nerve fibers （CSNFs） were obtained preoperatively and 1 and 3 months after surgery. Images of the CSNFs were analyzed to evaluate nerve regeneration. Data were analyzed using repeated measures ANOVA， an independent samples t test， Mann-Whitney U test and Spearman correlation analysis. Results  At 1 and 3 months after operation the average of BUT of F-LASIK group was significantly longer than that of M-LASIK group （t=-2.195， -2.174， P<0.05）. Schirmer I test results and the FS were comparable between the 2 groups. The nerve regeneration score was a little higher in F-LASIK group （1.03±0.63） than that in M-LASIK group （0.83±0.55） at 1 month after surgery， but there was no significant difference （Z=-1.400， P>0.05）. The nerve regeneration score in F-LASIK group （2.31±0.83） was significantly higher than that in M-LASIK group （1.93±0.80） at 3 months after surgery （Z=-2.100， P<0.05）. Significant positive correlations were found between Schirmer I test and the CSNFs regeneration score （r=0.231， P<0.01）， while there was no statistically significant associations between the CSNFs regeneration score and BUT （r=0.143， P>0.05） or FS （r=-0.049， P>0.05）. Conclusion  The recovery of tear dynamics and corneal subbasal nerve fibers is faster in FEMTO LDV LASIK than in traditional LASIK. Schirmer I test is increase with the CSNFs regeneration.

Objective To evaluate and compare the thickness and morphology of laser in situ keratomileusis （LASIK） flaps created by either the WaveLight FS-200 femtosecond laser or the Moria microkeratome M2 90 using anterior segment optical coherence tomography （AS-OCT）. Methods This was a prospective case-control study. Bilateral LASIK was performed on 61 myopic patients. Flaps were created using the WaveLight FS-200 femtosecond laser in 72 eyes and the Moria M2 90 microkeratome in 50 eyes. The thickness at 17 points across each flap， 0 mm， ±2 mm， and ±3.5 mm to the corneal vertex on the horizontal， vertical， 45° and 135° meridians， were evaluated using a Visante AS-OCT at 1 week postoperatively. An independent t test was used. Results The central flap thickness of the WaveLight group was 105.53±5.86 µm， while it was 132.96±13.91 µm in the Moria group （t=-13.16， P<0.01）. The difference between the achieved and the intended flap thickness （accuracy） was 6.17±3.98 µm and 23.60±12.64 µm， respectively （t=-15.20， P<0.01）. The standard deviation of thickness in the 17 points within an individual flap （uniformity） was 4.07±0.94 µm in the WaveLight group and 8.48±2.35 µm in the Moria group （t=-12.60， P<0.01）. The index S （Symmetry） of Moria group （33.81±11.28 µm） was significantly smaller in the WaveLight group （68.46±26.66 µm） （t=-8.67， P<0.01）. Conclusion AS-OCT showed that the flaps created with the WaveLight FS-200 femtosecond laser were more accurate， reproducible， and uniform than those created with the Moria M2 90 microkeratome.

Objective To evaluate the changes of retinal nerve fiber layer and macular parameters after femtosecond laser-assisted laser in situ keratomileusis （fs-LASIK） assessed by spectral-domain optical coherence tomography （SD-OCT）. Methods This prospective， consecutive study included 17 patients （33 eyes） with high （greater than -6.00 D） myopia treated with fs-LASIK. The macular thickness and volume and RNFLT measurements were performed using RTVue-100 OCT preoperatively and then on 1 day， 1 week and 1 month postoperation. The measurements before and after fs-LASIK were compared using one-way analysis of variance （ANOVA）. Results None of the RNFL parameters of whole， temporal， upper， nasal and below were observed to have a statistically significant change after fs-LASIK surgery （F=0.003， 0.503， 0.285， 0.164， 0.277， P>0.05）. Also， there was no statistically significant difference in macular thickness （F=0.491， 0.281， 0.234， 0.341， 0.614， 0.192， P>0.05） and volum （F=0.484， 0.968， 0.200， 0.314， 0.622， 0.206， P>0.05） of central fovea， parafovea， temporal， upper， nasal and below between pre- and postoperatively. Conclusion Femtosecond laser-assisted laser in situ keratomileusis has no significant effect on retinal nerve fiber layer and macular parameters determined by SD-OCT.

Objective To compare and analyze the higher-order aberrations （HOA）， contrast sensitivity（CS） and CS under the glare after FEMTO LDV femtosecond laser flap and mechanical microkeratome Hansatome flap in laser in situ keratomileusis （LASIK）. Methods This was a prospective clinical controlled study. Ninety-two eyes of 46 patients were treated with FEMTO LDV as the observation group， and 104 eyes of 52 patients were treated with Hansatome as the control group. Wavefront-guided LASIK （Zyoptix） was performed on each of these eyes after the flap preparation. HOA， CS and CS under the glare were evaluated before surgery and 1 week， 1 month， 3 months after treatment. Data were analyzed using chi-square test， ANOVA， independent t test. Results At 1 week after the surgery， 59/92（64.1%） patients in the observation group had uncorrected visual acuity （UCVA） levels reaching or surpassing the preoperative best corrected visual acuity （BCVA）， while in the control group， this rate was 76/104（73.1%）. At 1 month after the surgery， the rate of UCVA≥preoperative BCVA was 82/92（89.1％） in observation group and 96/104（92.3%） in control group. At 3 months after the surgery， the rate of UCVA≥preoperative BCVA was 86/92（93.5%） in observation group and 96/104（92.3%） in control group. The two groups were not significantly different after the surgery （x²=1.423， 1.112， 0.183， P＞0.05）. The refraction was +0.49±0.24 D in the observation group and +0.35±0.32 D in the control group at 1 week after surgery， while at 3 months， it was +0.10±0.18 D in the observation group and -0.14±0.22 D in the control group. The differences between the 2 groups were insignificant （t=0.566， 1.178， P>0.05）. Higher-order aberration. At 1 week and 3 months， the HOA and coma in the observation group were all lower than in the control group （t1 w=-2.422， -2.295， t3 m=-1.957， -1.926， P＜0.05）. There were no difference in spherical aberration and trefoil between the 2 groups （t1 w=-1.395， -0.779， t3 m=-1.205， -0.922， P＞0.05）. The 2 groups photopic CS was not significantly different after the surgery. The observation group mesopic CS decreased to the lowest level at 1 week postoperation， and returned to preoperative level at 1 month after operation. At 1 month and 3 months， the CS were higher than preoperation at 3.0， 18.0 c/d （F=3.602， 3.216， P＜0.05）. At 1 week after surgery， the mesopic CS of the observation group was better than the control group at 6.0 c/d （t=2.326， P＜0.05）. The 2 groups mesopic CS was not significantly different at 1 month and 3 months after operation. At 1 week after surgery， the photopic CS under the glare stimulus of the observation group was significantly higher than the control group at 3.0， 12.0 c/d （t=2.173， 2.327， P＜0.05）. At 3 months， the medium to low spatial frequencies （1.5， 3.0， 6.0 c/d） the mesopic CS of observation group was higher than the control group （t=2.428， 2.416， 2.507， P＜0.05）. Conclusion Patients undergoing femtosecond laser-assisted LASIK have better quality of vision after surgery than hansatome patients.

Objective To evaluate the safety and efficacy of topography-guided transepithelial photorefractive keratectomy （T-PRK） in the treatment of high and irregular astigmatism after penetrating keratoplasty （PKP）. Methods In this non-randomized retrospective study， 18 patients （20 eyes） with high or irregular astigmatism after PKP were treated with topography-guided T-PRK. Uncorrected distance visual acuity （UDVA）， corrected distance visual acuity （CDVA）， refraction， corneal topography， and subjective evaluation of visual symptoms were recorded and analyzed both preoperatively and at the last follow-up visit during this study. A Wilcoxon signed-rank test was used for the statistical analysis of UDVA， CDVA， refraction and corneal topography. Results At a mean follow-up time of 12.15±2.06 months postoperatively， mean UDVA and CDVA improved from 1.36±0.42 to 0.65±0.40 （Z=-3.727， P＜0.01）， and from 0.34±0.22 to 0.17±0.14 （Z=-3.607，P＜0.01）， respectively， with 10 eyes gaining two or more lines of CDVA. Moreover， mean sphere decreased from 1.48±3.14 D to -0.19±2.11 D （Z=-2.373， P＜0.05）； mean cylinder was reduced from -7.81±3.43 D to -3.06±1.99 D （Z=-3.792， P＜0.01）； the mean postoperative spherical equivalent （SE） refraction adjusted by intended SE was -1.72±2.55 D. Of all eyes， 3 eyes were within ±0.50 D of the intended refraction， 9 eyes were within ±1.00 D of the intended refraction. The mean corneal irregularity index （IRI） and orthogonal curvature asymmetry decreased from 66.33±22.03 μm to 59.11±14.66 μm （Z=-0.831， P＞0.05）， and from 8.96±4.36 D to 7.44±3.56 D （Z=-2.576， P＜0.05） respectively. All patients reported visual symptoms had improved or remained unchanged. Conclusion Topography-guided T-PRK appears to be a safe and effective treatment for post-PKP high and irregular astigmatism.

Objective To evaluate the morphologic characteristics around the blood vessels of the retinal vascular arcade with spectral-domain optical coherence tomography （SD-OCT） in eyes with high myopia. Methods One eye of 177 patients with binocular high myopia （refractive error ≥-8.00 diopters or axial length ＞26.5 mm） was randomly selected to undergo detailed SD-OCT scans along the entire posterior vascular arcade. High myopic eyes with paravascular retinal abnormalities were classified as the positive group and those eyes without paravascular retinal abnormalities were considered as the negative group. A independent t test was used to compare the age of patients， refractive error and the axial length of myopic eyes in these 2 groups. A chi-square test was used to compare the cases of staphyloma in 2 groups. Results Among 177 high myopia patients， paravascular retinal abnormalities were detected in 108 patients （61.0%） by SD-OCT. The mean age of patients in the positive group was 59.3±6.2 years， the mean refractive error of the 108 eyes was -13.55±3.43 D， and mean axial length was 29.57±2.06 mm. The mean age of the 69 patients in the negative group was 34.8±13.1 years， the mean refractive error was -9.50±3.07 D， and mean axial length was 27.02±1.02 mm. The differences in the age of the patients （t=10.466）， refractive error （t=7.454） and axial length （t=10.979） of myopic eyes between these two groups were statistically significant （P<0.05）. In the positive group， paravascular retinal cysts and microfolds were detected in all of the 108 eyes （100.0%）， paravascular lamellar holes in 65 eyes （60.2%）， paravascular retinoschisis in 53 eyes （49.1%）， and tractional detachment of the retina in 1 eye （0.9%）. All of the paravascular retinal abnormalities were located within staphyloma area of 2 to 3 PD from the optic disc. There were 101 eyes with staphyloma in the positive group and 48 eyes with staphyloma in the negative group. The difference between the 2 groups was statistically significant （x²=16.999， P<0.05）. Conclusion The present study illustrates that subtle but relatively common structural abnormalities occur in highly myopic eyes. Pathologic alterations in the vitreous cortex and staphyloma may be responsible for a variety of paravascular retina abnormalities. SD-OCT is necessary to diagnose and investigate paravascular retinal changes in highly myopic eyes.

Objective To observe the clinical outcome of the Rose K rigid gas permeable contact lens （RGPCL） used to correct advanced keratoconus with refractive errors. Methods Fifty-nine eyes of 55 patients with advanced keratoconus who were fitted at the Shandong Eye Hospital with a Rose K RGPCL between February 2011 and May 2012 were included in this retrospective study. Fluoresein staining was used to fit the contacts lenses. Differences in mean values among groups were compared with a one-way ANOVA. The corneal curvature values of a 9 mm diameter centered on the apex of the topographic map were compared for the 4 meridians of 0°， 90°， 180°， 270°. Uncorrected visual acuity （UCVA）， best spectacle-corrected visual acuity （BSCVA） and best-corrected RGPCL visual acuity （RGPCLVA） were compared. Visual acuity under the same contrast were compared for UCVA， BSCVA and RGPCLVA. The curvature radius of the flat meridian （Sim K1）， steep meridian （Sim K2）， and mean K were compared with the base curve （BC） of the RGPCL. Results There were significant differences between the corneal curvature values of the 4 peripheral points and the apex on the topographic map （P<0.01）. The Rose K RGPCL reached an ideal fit by fluoresein staining. There were statistically significant differences between RGPCLVA and UCVA or BSCVA （P<0.01）. And the same outcomes were found for the 100%， 25%， 10% and 5% contrast visual acuity charts. There were no significant differences in the relationship between the BC of RGPCL and the residual Sim K1 or mean K. Conclusion The Rose K RGPCL lenses provide ideal fitting， good visual acuity and contrast vision for advanced keratoconus. The trial Rose K RGPCL was chosen based on the Sim K1 or mean K.

Objective To investigate the clinical effect of mitomycin C （MMC） on the corneal endothelium and corneal posterior surface after laser subepithelial keratomileusis （LASEK）. Methods In a continuity prospective double-blind study， 0.02% MMC was used topically for 20 seconds in 33 eyes of 33 patients who had undergone LASEK after excimer laser ablation in the Fudan EENT Hospital. The other eye of these patients without MMC treatment was used as the control. Three and 6 months after surgery， the changes in the curve and elevation of the corneal posterior surface， and the density and variation coefficient of corneal endothelial cells were observed to evaluate the MMC toxicity． Data were analyzed using a paired t test. Results In the MMC-treated eyes， 3 and 6 months after the operation， the average corneal endothelium cell density was 3353.3±290.3 cells/mm2 and 3407.6±298.4 cells/mm2； the variation coefficient was 13.36%±6.29% and 13.48±4.34%. In the control eyes 3 and 6 months after the operation， the average corneal endothelium cell density was 3258.7±284.6 cells/mm2 and 3339.2±213.4 cells/mm2； the variation coefficient was 14.52%±7.85% and 14.06%±6.50%. The changes in the elevation and curve of the corneal posterior surface in the MMC treated eyes were -0.67±2.26 μm and -0.52±2.67 μm and 0.01±0.20 D and 0.01±0.21 D， 3 and 6 months after the operation. The changes in the control eyes were -0.85±2.31 μm and -0.15±3.00 μm and -0.01±0.22 D and 0.05±0.17 D at the respective time points after the operation. There were no significant differences in the above parameters either between preoperative or postoperative data or between these two groups. Conclusion The study showed that the application of 0.02% mitomycin C in LASEK is safe.

Objective To evaluate the effect of posterior capsular opacification and Nd∶YAG laser capsulotomy on the accommodative function of the 1CU accommodative intraocular lens （1CU AIOL）. Methods This was a retrospective study. Twenty patients （24 eyes） with posterior capsular opacification after phacoemulsification and implantation of an 1CU AIOL were included in the study. Uncorrected distance visual acuity， best corrected distance visual acuity （5 m）， distance corrected intermediate visual acuity （50 cm）， distance corrected near visual acuity （33 cm）， and amplitude of accommodation with subjective techniques of near point and defocusing were measured at 3 months after ICU AIOL surgery， 1 day before Nd∶YAG laser capsulotomy and 3 months after Nd∶YAG laser capsulotomy. All data were statistically analyzed with repeated measure analysis of variance （ANOVA）. Results Compared to 3 months after ICU AIOL surgery， uncorrected distance visual acuity （F=108.87， P＜0.01）， best corrected distance visual acuity （5 m） （F=116.97， P＜0.01）， distance corrected intermediate visual acuity （50 cm） （F=79.89， P＜0.01）， distance corrected near visual acuity （33 cm） （F=118.84， P＜0.01）， and amplitude of accommodation （F=81.78， P＜0.01） with subjective techniques of near point and defocusing had all decreased at 1 day before Nd∶YAG laser capsulotomy， and had increased by 3 months after Nd∶YAG laser capsulotomy. The differences were statistically significant. There was no statistically significant difference between the two methods for measuring amplitudes of accommodation （F=0.272， P＞0.05）. Conclusion Conclusion The accommodative function of the 1CU AIOL had obviously decreased because of the presence of posterior capsular opacification and recovered after Nd∶YAG laser capsulotomy 3 months after surgery.

Objective To study the correlation between the stimulus and response AC/A ratios by measuring a patient′s accommodative lag and eye position using different stimuli to induce accommodation. Methods A cross-sectional study was used. Twenty-nine myopic college students（average age 23.3±3.8） were randomly selected for the study. Phoria was measured at distances of 40 cm and 5 m by prism separation when wearing full correction. Phoria was measured again at a distance of 40 cm after adding spherical lenses of +1.00 D， +1.50 D， -1.00 D and -2.00 D. Accommodative lag was then measured with each lens power by the monocular estimation method using dynamic retionscopy. Finally， the data were analyzed by a rank-sum test. Results There were statistically significant differences between accommodative lag and gradient response and stimulus AC/A ratios when different accommodative stimuli were used （x²=116.85， 8.992， 17.319， P<0.05）. The correlation coefficients between response and stimulus AC/A ratios based on the gradient method were 0.542（P<0.01）， 0.789（P<0.01），and 0.812（P<0.01） with added lenses of +1.00 D， -1.00 D， -2.00 D. And the correlation coefficient between response and stimulus AC/A ratios based on the calculation method was 0.859（P<0.01）. Conclusion A subject has less accommodative response and more accommodative lag with minus spherical addition than with a plus spherical addition lens. The correlation between stimulus and response AC/A ratios is highest when using a calculation method.

Axial length （AL） elongation is the major factor in the development of myopia so it is of great importance to study its growth pattern and mechanism. Factors like age， gender， height， parental myopia， and near work were found to have an influence on AL growth. AL combined with the above factors and other ocular parameters could be of value in predicting the onset of myopia. This article summarizes the risk factors for AL and the predictive value of AL for myopia.

Dendritic cells， having two distinct functional states， are professional antigen-presenting cells. Immature dendritic cells induce immunity tolerance but mature dendritic cells are uniquely able to efficiently stimulate naive T-cell responses. While the peripheral cornea contains mature and immature dendritic cells， the central cornea is endowed exclusively with highly immature dendritic cells. The role of dendritic cells in corneal-associated diseases is reviewed in this article.