Safety and satisfaction of myopic small-incision lenticule extraction combined with monovision.

BACKGROUND: To investigate the safety and optical quality of small-incision lenticule extraction (SMILE) combined with monovision, and patient satisfaction with the procedure. METHODS: The present study assessed a non-random case series involving 60 eyes of 30 patients (mean age 45.53 ± 3.20 years [range 41 to 52 years]) treated bilaterally using the VisuMax 500 system (Carl Zeiss Meditec, Jena, Germany) between January and July 2016. The target refraction was plano for the distance eye, and between - 0.5 and - 1.75 diopters (D) for the near eye. Visual acuity, refraction errors, ocular aberrations, and satisfaction questionnaire scores were calculated 1 year after surgery. RESULTS: All surgeries were uneventful, with a mean safety index of 1.03 and 1.04 in dominant and nondominant eyes, respectively. Binocular uncorrected distance visual acuity of all patients was ≥20/32, while binocular uncorrected near visual acuity was ≥20/40 1 year postoperatively. Higher-order aberration (0.45 ± 0.14, 0.51 ± 0.15 µm), spherical (0.18 ± 0.15, 0.21 ± 0.14 µm) and coma aberration (0.31 ± 0.16, 0.27 ± 0.17 µm) were identical between dominant and nondominant eyes after surgery. The overall satisfaction rate was 86.7% (26/30), with large contributions from age (OR = 1.76 95% CI: 1.03-2.53; P = 0.036). Binocular uncorrected distance visual acuity was related to preoperative spherical diopter (r = - 0.500; P = 0.005). CONCLUSIONS: Monovision appears to be a safe and effective option for myopia patients with presbyopia who are considering the SMILE procedure. Patients with younger age were more satisfied with the procedure.

Refractive change in the adult rabbit eye after corneal relaxation with the femtosecond laser.

BACKGROUND: A new procedure to correct myopia that does not disturb the cornea in the optical zone and avoids injuring the corneal epithelium could be a key advance in corneal refractive surgery. The aim of this study is to observe the refractive change in the adult rabbits undergoing femtosecond laser-assisted multilayer intrastromal ablation in the mid-periphery of the cornea without injury of epithelium. METHOD: The right eyes of 8 New Zealand White adult rabbits were used for the experiments. A 60-kHz femtosecond laser delivery system was used, and three lamellar layers of laser pulses were focused starting at a corneal depth of 180 µm and ending at 90 µm from the surface, with each successive layer placed 45 µm anterior to the previous layer. In the interface of the applanation contact lens cone, a 6-mm diameter aluminum circle was placed at the center to block the laser, limiting ablation to the mid-periphery of the cornea. The laser settings were as follows: spot/line separation, 10 µm; diameter, 8.0 mm; energy for ablating the stroma, 1.3 µJ. An authorefractor was used to assess the manifest refraction. RESULTS: Mean spherical equivalent (SE) (mean ± SD, SD: standard deviation) was significantly increased at postoperative week 1 (1.67 ± 0.26 D, p < 0.0001), month 1 (1.65 ± 0.23 D, p < 0.0001), and month 3 (1.60 ± 0.22 D, p < 0.0001) compared to baseline (0.68 ± 0.27 D). Mean spherical equivalent showed no significant change between postoperative week 1 and month 3 (p = 0.1168). CONCLUSION: Femtosecond laser-assisted multilayer corneal intrastromal ablation in the mid-periphery may cause a consequent hyperopic shift with no refractive regression.

Recent advances in the biosynthesis of fungal glucan structural diversity.

Glucans are the most abundant class of macromolecule polymers in fungi, which are commonly found in Ascomycota and Basidiomycota. Fungal glucans are not only essential for cell integrity and function but also crucial for the immense industrial interest in high value applications. They present a variety of structural characteristics at the nanoscale due to the high regulation of genes and the involvement of stochastic processes in synthesis. However, although recent findings have demonstrated the genes of glucans synthesis are relatively conserved across diverse fungi, the formation and organization of diverse glucan structures is still unclear in fungi. Here, we summarize the structural features of fungal glucans and the recent developments in the mechanisms of glucans biosynthesis. Furthermore, we propose the engineering strategies of targeted glucan synthesis and point out the remaining challenges in the synthetic process. Understanding the synthesis process of diverse glucans is necessary for tailoring high value glucan towards specific applications. This engineering strategy contributes to enable the sustainable and efficient production of glucan diversity.

Ten-year observation of corneal densitometry and associated factors following small incision lenticule extraction.

AIM: To investigate the long-term changes of corneal densitometry (CD) and its contributing elements after small incision lenticule extraction (SMILE). METHODS: Totally 31 eyes of 31 patients with mean spherical equivalent of -6.46±1.50 D and mean age 28.23±7.38y were enrolled. Full-scale examinations were conducted on all patients preoperatively and during follow-up. Visual acuity, manifest refraction, axial length, corneal thickness, corneal higher-order aberrations, and CD were evaluated. RESULTS: All surgeries were completed successfully without complications or adverse events. Ten-year safety index was 1.17±0.20 and efficacy 1.04±0.28. CD value of 0-6 mm zones in central layer was statistically significantly lower 10y postoperatively, compared with preoperative values (0-2 mmΔ=-1.62, 2-6 mmΔ=-1.24, P<0.01). There were no correlations between CD values and factors evaluated. CONCLUSION: SMILE is a safe and efficient procedure for myopia on a long-term basis. CD values get lower 10y postoperatively, whose mechanism is to be further discussed.

Accurate prediction of myopic progression and high myopia by machine learning.

Background: Myopia is a leading cause of visual impairment in Asia and worldwide. However, accurately predicting the progression of myopia and the high risk of myopia remains a challenge. This study aims to develop a predictive model for the development of myopia. Methods: We first retrospectively gathered 612 530 medical records from five independent cohorts, encompassing 227 543 patients ranging from infants to young adults. Subsequently, we developed a multivariate linear regression algorithm model to predict the progression of myopia and the risk of high myopia. Result: The model to predict the progression of myopia achieved an R2 value of 0.964 vs a mean absolute error (MAE) of 0.119D [95% confidence interval (CI): 0.119, 1.146] in the internal validation set. It demonstrated strong generalizability, maintaining consistent performance across external validation sets: R2 = 0.950 vs MAE = 0.119D (95% CI: 0.119, 1.136) in validation study 1, R2 = 0.950 vs MAE = 0.121D (95% CI: 0.121, 1.144) in validation study 2, and R2 = 0.806 vs MAE = -0.066D (95% CI: -0.066, 0.569) in the Shanghai Children Myopia Study. In the Beijing Children Eye Study, the model achieved an R2 of 0.749 vs a MAE of 0.178D (95% CI: 0.178, 1.557). The model to predict the risk of high myopia achieved an area under the curve (AUC) of 0.99 in the internal validation set and consistently high area under the curve values of 0.99, 0.99, 0.96 and 0.99 in the respective external validation sets. Conclusion: Our study demonstrates accurate prediction of myopia progression and risk of high myopia providing valuable insights for tailoring strategies to personalize and optimize the clinical management of myopia in children.

Transfer from blue light or green light to white light partially reverses changes in ocular refraction and anatomy of developing guinea pigs.

Relative to the broadband white light (BL), postnatal guinea pigs develop myopia in a monochromic middle-wavelength light (ML, 530 nm) environment and develop hyperopia in a monochromic short-wavelength light (SL, 430 nm) environment. We investigated whether transfer from SL or ML to BL leads to recuperation of ocular refraction and anatomy of developing guinea pigs. Two-week-old guinea pigs were given (a) SL for 20 weeks, (b) SL recuperation (SLR, SL for 10 weeks then BL for 10 weeks), (c) ML for 20 weeks, (d) ML recuperation (MLR, ML for 10 weeks then BL for 10 weeks), or (e) BL for 20 weeks. Two weeks after transfer from ML to BL (MLR group), ocular refraction increased from 1.95 ± 0.35 D to 2.58 ± 0.24 D, and vitreous length decreased from 3.48 ± 0.06 mm to 3.41 ± 0.06 mm. Two weeks after transfer from SL to BL (SLR group), ocular refraction decreased from 5.65 ± 0.61 D to 4.33 ± 0.49 D, and vitreous length increased from 3.18 ± 0.07 mm to 3.26 ± 0.11 mm. The MLR and SLR groups had final ocular refractions that were significantly different from those of the ML and SL groups at 20 weeks (ML vs. MLR: p < 0.0001; SL vs. SLR: p < 0.0001) but were still significantly different from the BL group (BL vs. MLR: p = 0.0120; BL vs. SLR: p = 0.0010). These results suggest that recuperation was not complete after return to BL for 10 weeks.

[Partial rectus muscle transposition for strabismus with lateral rectus muscles paralysis].

OBJECTIVE: To investigate surgical approach for paralytic strabismus with lateral rectus muscles paralysis and evaluate its clinical effects. METHODS: Design retrospective, observational case series. 28 patients (31 eyes) who underwent augmented partial rectus muscle transposition (APRMT) in the treatment of paralytic strabismus with lateral rectus muscles paralysis from May 2009 to May 2011 at Eye & ENT Hospital of Fudan University were included in this study. The following data were analyzed: (1) The procedure that was performed, (2) The angle of deviation of primary position, (3) The presence of compensatory head posture, (4) The presence of diploma in the primary position, (5) The binocular single visual fields, (6) The motility of the affected eye. RESULTS: According to the results of rectus muscle forced traction test and examination before and after operation, among 31 eyes in 28 patients, 8 eyes were treated with APRMT, 10 eyes were treated with recession of antagonistic muscle of paralytic rectus muscle combined with APRMT, 7 eyes were treated with APRMT and recession of yoke muscle, 6 eyes were treated with APRMT and recession of yoke muscle combined with recession of antagonistic muscle. 17 among 28 patients were orthotopic in the primary position while others were in mild under correction with deviation no more than 10 prism degrees during 5 months (range: 3-8 months) follow-up in average. The diploma and abnormal head posture were eliminated in 26 patients except one patient who was appeared with 10 prism degrees under correction postoperatively and was resolved by wearing prisms thereafter. Binocular single visual fields were extended from 27.0° ± 6.4 ° preoperatively to 40.5° ± 4.8 ° postoperatively (t = -34.692, P < 0.001). Ocular movement was improved from -4.9 ± 0.4 to -2.9 ± 0.9 postoperatively (t = -13.418, P < 0.001). CONCLUSIONS: APRMT can safely and effectively correct the primary position in paralytic strabismus with lateral rectus muscles paralysis, eliminate the presence of diploma in primary position and abnormal head posture, and improve the ability of the ocular movement, furthermore, significantly expand the scope of binocular single visual fields. The results also demonstrate that rectus muscle forced traction test is a key measurement to determine the surgical procedure.

Electroacupuncture for mild-to-moderate dry eye: study protocol for a multicentre, randomised, single-blind, sham-controlled trial.

INTRODUCTION: Dry eye (DE) is a multifactorial ocular surface disease causing considerable medical, social and financial implications. Currently, there is no recognised long-term, effective treatment to alleviate DE. Clinical evidence shows that electroacupuncture (EA) can improve DE symptoms, tear secretion and tear film stability, but it remains controversial whether it is just a placebo effect. We aim to provide solid clinical evidence for the EA treatment of DE. METHODS AND ANALYSIS: This is a multicentre, randomised, sham-controlled trial. A total of 168 patients with DE will be enrolled and randomly assigned to EA or sham EA groups to receive 4-week consecutive treatments and follow-up for 24 weeks. The primary outcome is the change in the non-invasive tear break-up time (NIBUT) from baseline to week 4. The secondary outcomes include tear meniscus height, the Schirmer I test, corneal and conjunctival sensation, the ocular surface disease index, corneal fluorescein staining, the numerical rating scale and the Chinese DE-related quality of life scale. ETHICS AND DISSEMINATION: The trial protocol and informed consent were approved by the Ethics Committee of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine (identifier: 2021-119), Shanghai Eye Disease Prevention and Treatment Center (identifier: 2022SQ003) and Eye and ENT Hospital of Fudan University (identifier: 2022014). TRIAL REGISTRATION NUMBER: NCT05552820.

[Advances in biomechanical effects of laser corneal refractive surgery].

Corneal biomechanical properties will change after laser refractive surgery, which can be evaluated by several biomechanical parameters. The biomechanical stress will decrease remarkably after LASIK, but thin flap is helpful to maintain its stress. Excimer laser surface ablation has biomechanical advantages over LASIK procedure. The femtosecond laser technology can achieve smooth and regular incision and make the angle design. Flap adhesion is stronger when completed by a femtosecond laser. Laser refractive surgery will become safer and achieve more stable outcomes with the emphasis on biomechanical effects.

[The progress of fixation eye movement research].

When eyeball fixes targets, it will produce one frequent and regular movement which is difficult to detect. Such movements is called fixation eye motion. This motion can be further divided into drift, tremor and microsaccades. In recent years, research in this field is strikingly increasing. Due to the significant role on the control of fixation positron, maintaining continuous sense of perception, keeping bistable condition, clear vision, spatial orientation and attention, research in this field is maybe a worthwhile myopia research direction.

Refractive outcomes and optical quality of PRESBYOND laser-blended vision for presbyopia correction.

AIM: To investigate the one-year refractive outcomes and optical quality following PRESBYOND laser-blended vision (LBV). METHODS: This retrospective study included 20 patients who underwent PRESBYOND treatment between Jan 2019 and Aug 2020. The patients were asked to attend a follow-up outpatient visit one year after surgery. Distance and near visual acuity as well as subjective refraction were examined. Optical quality was assessed using wavefront-supported custom ablation. A questionnaire evaluating optical quality and satisfaction was completed at the last visit. RESULTS: The average patient age was 48.1±7.4y (range, 41 to 58y). The mean preoperative spherical equivalent was -7.59±2.39 D. At the one-year follow-up, two eyes (both dominant eyes) lost one line of corrected distance visual acuity (CDVA), while the remaining eyes (38/40) maintained or gained lines of CDVA. The average binocular uncorrected distance visual acuity improved from 0.15±0.03 to 0.90±0.26 (decimal vision; P<0.001). The average binocular uncorrected near visual acuity increased from 0.34±0.28 to 0.97±0.07 (P<0.001). The spherical aberration was 0.04±0.06 µm in the nondominant eye and 0.09±0.09 µm in the dominant eye (P=0.02). All patients were satisfied with or accepted the outcomes of the surgery. The primary complaints were related to disturbances in night vision and relatively inferior near vision. CONCLUSION: Over the one-year observation period, PRESBYOND is a safe and effective option for presbyopia correction. The optical quality and near vision deserve further investigation.

Corneal histomorphology and electron microscopic observation of R124L mutated corneal dystrophy in a relapsed pedigree.

AIM: To investigate the histological characteristics and ultrastructure of recurrent Chinese R124L mutated corneal dystrophy after keratoplasty. METHODS: The subjects were enrolled from a Chinese family of corneal dystrophy with R124L heterozygous gene mutation and with a history of consanguineous marriage. Normal corneal samples were used as controls. RESULTS: In this family, 2 patients (3 eyes) underwent penetrating keratoplasty (PKP) and 2 patients (4 eyes) underwent lamellar keratoplasty (LKP). They had recurrence at 33.5±3.0 (range 30-36)mo after keratoplasty. Among them, 1 patient (1 eye) underwent PKP again and 1 patient (2 eyes) underwent LKP again. In the R124L mutated recurrent corneal dystrophy, the corneal turbidity was mainly distributed from the upper corneal cortex to the anterior stroma; the corneal epithelium surface was rougher and more uneven; and, the corneal erosions were larger. Hematoxylin-eosin staining showed that the thickness of the corneal epithelium was uneven; the arrangement of the epithelial cells was disordered; and, some corneal epithelial cells were swollen. The results of Congo red staining, Masson's trichrome staining and Periodic acid-Schiff staining were positive, while that of Alcian blue staining was negative. Under a transmission electron microscope, deposition of high electron density substances between epithelial and basal cells, and, apoptosis of basal cells were observed. Many high electron density depositions were observed in the sub-epithelial and anterior corneal matrix. CONCLUSION: In the Chinese family of recurrent corneal dystrophy with R124L gene mutation, the corneal epithelia of the recurrent cases are rougher, and the corneal depositions are extracellular amyloid fibrin.

The role of eIF5A in epidermal growth factor-induced proliferation of corneal epithelial cell association with PI3-k/Akt activation.

PURPOSE: After excimer laser surgery, epidermal growth factor (EGF) plays an important role in injured corneal epithelial cell on myofibroblastic cell formation in corneal stroma. The purpose of the study is to investigate the precise mechanism of EGF on corneal wound healing, particularly on epithelial proliferation and migration. METHODS: In this study we applied small interference RNA (siRNA) to knock down the expression of eukaryotic translation initiation factor 5A (eIF5A) in corneal epithelial cells. The relative mRNA and protein expression of matrix metallopeptidase 9 (MMP9) and proliferating cell nuclear antigen (PCNA) was determined via real-time PCR and western blot analysis. The proliferative potential of EGF was evaluated via a proliferation assay using the measurement of (3)H-thymidine incorporation ((3)H-TdR). HCEpiC apoptosis was subjected to flow cytometric analysis. RESULTS: The results showed eIF5A expression was enhanced and there was a statistically significant increase in EGF treatment compared to the control group. Real-time PCR, western blot analysis, and the proliferation assay demonstrated significantly lower MMP9 and PCNA expression and proliferation cell counts in eIF5A siRNA-treated groups versus significantly higher levels in EGF plus eIF5A siRNA-treated groups. The data analysis showed that eIF5A, MMP9, and PCNA expression decreased as a result of the inhibitor LY294002. Apoptotic cells were increased in the EGF plus eIF5A siRNA, EGF plus LY294002, and EGF plus eIF5A siRNA plus LY294002 groups as compared with the EGF siRNA group. CONCLUSIONS: These results indicate that EGF-induced upregulation of eIF5A stimulates corneal epithelial cell proliferation in vitro. EGF stimulation of corneal epithelial proliferation was through the phosphatidylinositol 3-kinase (PI3-k)/protein kinase B (Akt) signaling pathway.

Effects of different monochromatic lights on refractive development and eye growth in guinea pigs.

We investigated whether different monochromatic lights with similar luminance or identical light quantum number produce predictable changes in refractive state and eye growth in early eye development in guinea pigs. In experiment I, three groups of guinea pigs (two weeks of age, n=18 in each group) were reared for 12 weeks under LED lighting of 430 nm (short-wavelength light, SL), 530 nm (middle-wavelength light, ML), and broad-band light (BL). The lighting conditions were set to provide equal levels of luminance. All animals underwent refraction and biometric measurements every 2 weeks. In experiment II, the lighting conditions were set at equal quantum number and another three groups of guinea pigs were raised and tested for 20 weeks. In experiment I, compared to the BL group, refraction of the ML group was less hyperopic (P<0.001) with a faster vitreous extension (P<0.001), while the SL group was more hyperopic with a slower vitreous elongation (P<0.001). The mean difference in refraction between the SL and ML groups reached about 4.5 D at maximum. The refractive changes and eye growth in experiment II were very similar to experiment I during the first 12 weeks, but the difference in refraction between the SL and ML groups reached 6.05 D after 20 weeks of treatment, which was greater than the longitudinal chromatic aberration (approximately 1.5 D) in the guinea pigs eyes. The results suggest that the guinea pigs' eyes overcompensated in response to narrow-band light, which resulted in an exaggerated and inaccurate refractive growth.

Influence of internal optical astigmatism on the correction of myopic astigmatism by LASIK.

PURPOSE: To investigate the influence of the origin of astigmatism on the correction of myopic astigmatism by LASIK. METHODS: A retrospective study was conducted of the records of 192 patients (192 eyes) undergoing LASIK for correction of myopia and myopic astigmatism from January to September 2010. Ocular residual astigmatism (ORA) and lenticular astigmatism (LA) were determined by vector analysis using objective refraction and Pentacam (Oculus Optikgeräte GmbH) imaging of both corneal surfaces. Patients were divided into two groups according to ORA (high ORA group: ORA/preoperative refractive astigmatism >1; normal ORA group: ORA/preoperative refractive astigmatism ≤ 1) and LA (high LA group: LA/preoperative refractive astigmatism >1; normal LA group: LA/preoperative refractive astigmatism ≤ 1). Procedural efficacy was compared between those eyes with and without a significant amount of internal optical astigmatism using index of success. RESULTS: Mean preoperative vectors for the astigmatism of the anterior cornea, posterior cornea, and lens were -1.33 × 3.0°, -0.33 × 95.3°, and -0.27 × 103.3°, respectively. Mean indices of success in the high and low ORA groups were 1.75 and 0.59, respectively (t=7.81, P<.001). Mean indices of success in the high and low LA groups were 2.07 and 0.70, respectively (t=12.36, P<.001). The higher indices of success in the high ORA and high LA groups suggest a lower efficacy of LASIK in treating astigmatism primarily located intraocularly. CONCLUSIONS: Myopic LASIK is less effective in correcting astigmatism when astigmatism is mainly located at the internal optics. Topography and refractive value should be incorporated in the treatment of patients when a significant amount of internal optical astigmatism is detected preoperatively.

[The effects of protein-free calf blood extract for recovery of corneal nerve after LASEK and LASIK].

OBJECTIVE: To evaluate the effects of protein-free calf blood extract for recovery of corneal nerve after LASEK and LSEIK. METHODS: A prospective, randomized, control and double-blind study was carried out from January through February 2009 at Department of Ophthalmology, Eye Ear Nose and Throat Hospital of Fudan University. Forty-nine eyes of 25 patients who underwent LASEK were randomly divided into two groups. One group with 16 patients (32 eyes) was treated by protein-free calf blood extract eye gel which was defined as drug treated group and the other group with 9 patients (17 eyes) was not treated by protein-free calf blood extract eye gel which was defined as no drug treated group. Forty-four eyes of 23 patients who underwent LASIK were also randomly divided into two groups. One group with 13 patients (24 eyes) was treated by protein-free calf blood extract eye gel which was defined as drug treated group and the other group with 10 patients (20 eyes) was not treated by protein-free calf blood extract eye gel which was defined as no drug treated group. Protein-free calf blood extract eye gel was delivered in both drug treated groups 3 times per day for three months after surgery. Laser scanning confocal microscopic examinations were performed on 48 eyes in vivo. Central corneal sensitivity and tear break-up time (BUT) were tested on 93 eyes preoperatively and 1, 3, 6 months, and 1 year after surgery. The obtained dates in the study were analyzed using independent samples t-test, paired t-test and Mann-Whitney Test. RESULTS: The morphology observed by confocal microscope of sub-basal nerve fibers was not different between drug treated group and no drug treated group until the last follow up after LASIK or LASEK (Z = 0.0000, P = 1.00) and (Z = 0.0000, P = 1.00). Nerve fibers with interconnections were observed in drug treated group at 3 months after LASEK. The morphology of sub-basal nerve fibers had not recovered completely until 1 year after surgery. The central corneal sensitivity was better in drug treated group than in no drug treated group at 1 month after LASEK [(4.95 ± 0.84) µm, (3.62 ± 1.38) µm; t = 4.23, P < 0.01] and at 1 and 3 months after LASIK [(3.29 ± 1.40)µm, (2.35 ± 1.51) µm; t = 2.10, P < 0.05], [(4.31 ± 1.61) µm, (3.18 ± 1.62) µm; t = 2.31, P < 0.05]. At 6 months postoperatively, the central corneal sensitivity of both drug treated group and no drug treated group which underwent LASEK was not significantly different from pre-operation [(5.81 ± 0.35) µm; t = -1.26, P > 0.05], [(5.79 ± 0.36) µm; t = -0.70, P > 0.05]. At 6 months postoperatively, the central corneal sensitivity of drug treated group which underwent LASIK was not significantly different from pre-operation [(5.25 ± 0.91) µm; t = -1.87, P > 0.05]. No significant difference was seen in BUT between drug treated group and no drug treated group after LASEK or LASIK until 1 year after surgery [(8.13 ± 2.18) µm, (8.76 ± 1.64) µm; t = -0.90, P > 0.05], [(7.71 ± 2.14) µm, (7.45 ± 2.37) µm; t = 0.30, P > 0.05]. CONCLUSION: Protein-free calf blood extract could significantly promote the recovery of corneal nerve in the early period after LASEK and LASIK.

[The clinical study of femtosecond lenticule extraction for myopia].

OBJECTIVE: To evaluate the clinical efficacy, safety and predictability of femtosecond lenticule extraction (FLEx) for myopia. METHODS: This is a prospective Clinical trial involved 10 cases (10 eyes). The patients aged from 18 years old to 53 years old, an average of (34 ± 11) years old. Femtosecond lenticule extraction (FLEx) was used to treat myopia from -4.88 DS to -9.25 DS, an average of (-6.94 ± 1.50) DS with cylinder from 0.50 DC to 3.0 µm DC an average of (1.28 ± 0.73)DC. Their corneal thickness were (527.10 ± 29.05) µm in an average. The patients were followed up for 6 to 10 months with visual acuity, manifest refraction, intraocular pressure, wavefront aberration, corneal topography and optical coherence tomography (OCT). SPSS software was used to analysis. RESULTS: FLEx procedure was done well in every patients without any scanning problem. No infection happened to in the trial. The patients' UCVA improved to 0.6 - 1.2 while BCVA improved 0.7 - 1.2 postoperatively. BCVA improved more than 2 lines in 2 eyes whereas 1 line in 2 eyes. No eye lost BCVA. The difference between pre-and postoperative refraction was within ± 0.75 DS, an average of SE (-0.25 ± 0.33) DS. No epicenter showed in topography. Spherical aberration increased slightly in 8 eyes but decreased in 2 eyes. OCT showed that stroma bed fit to each other very well. CONCLUSION: Femtosecond lenticule extraction appears to be efficiency, safety and predictable for myopia. Femtosecond lenticule extraction could have a good stroma fit. Its wavefront aberration changes need to further investigation.

[Relationship between best corrected visual acuity and refraction parameters in myopia].

OBJECTIVE: To explore the relationship between best corrected visual acuity (BCVA) and refraction parameters in myopia. METHODS: Two thousand two hundred and seventy-four patients (4245 eyes) with different degrees of myopia were collected. Their BCVA, diopter of spherical (DS), diopter of cylinder (DC), astigmatism axis, axial length (AL) and corneal thickness were detected. The influence of those parameters on BCVA was studied and the mathematical model of the relationship between BCVA and other parameters including the age and gender of patients was established. RESULTS: The logistic regression analysis showed that there were correlations between the BCVA (y) and DS (x1), DC (x2), gender (x3), AL (x4), corneal thickness (x5), astigmatism axis (x6) and age (x7) (P<0.05): y=0.580 6-0.034 0 x1-0.046 8 x2+0.056 5 x3+0.016 5 x4+ 0.0007 x5+0.000 2 x6-0.005 8 x7. CONCLUSION: For people with myopia, age, gender and corneal thickness have small effect on BCVA, while the DS, DC, AL and astigmatism axis have significant effect on BCVA. The BCVA would decline following the extension of DS, DC and AL. It is helpful to assess the vision of myopia by analyzing the refraction parameters comprehensively.

One-step viscoelastic agent technique for ICL V4c implantation for myopia.

AIM: To investigate the safety and efficacy of using a one-step viscoelastic agent technique for posterior chamber phakic implantable collamer lens with a central hole (ICL V4c) implantation for myopia correction. METHODS: The one-step viscoelastic agent technique for ICL V4c implantation was used in 100 eyes of 52 patients. Refractive outcomes, intraocular pressure (IOP), corneal endothelial cell, and corneal densitometry values were evaluated at 1d, 1wk, 1 and 3mo postoperatively. RESULTS: All the surgeries were uneventful. No corrected distance visual acuity was lost after 3mo. IOP was 16.12±3.18 mm Hg before surgery, and 14.74±3.08 mm Hg at 1d and 14.50±2.56 mm Hg at 3mo after surgery (P<0.05). Corneal endothelial cell density was 2580±242 cell/mm2, the coefficient of variation in cell size was 42.11%±7.92%, and the percentage of hexagonal cells was 40.98%±9.46% before surgery. No significant difference was found when these outcomes were compared between the studied time points (P>0.05). The corneal densitometry values of the central 2 mm and 2 to 6 mm areas showed similar regularities. After surgery, the values significantly increased at 1d, then decreased to the preoperative values at 1wk, and then continued to decrease at 3mo (P<0.05). CONCLUSION: The one-step viscoelastic agent technique for ICL V4c implantation is found to be safe and effective for myopia correction and causes little disturbance to the cornea.

A Randomized Controlled Trial of the Effect of 0.01% Atropine Eye Drops Combined with Auricular Acupoint Stimulation on Myopia Progression.

BACKGROUND: Use of 0.01% atropine eye drops (0.01% A) is one of the most common treatments for myopia control for children in Asia. Auricular acupoint stimulation (AAS) was reported to enhance the effect of higher-concentration atropine (0.25%, 0.125%) on myopia control. This study was designed to compare the effect of 0.01% A combined with AAS and 0.01% A alone on myopia progression and choroidal thickness in children. METHODS: A total of 104 children were stratified by age and randomly assigned at 1 : 1 to receive 0.01% A or 0.01% A + AAS treatment for 6 months. Repeated measurements of cycloplegic spherical equivalent (SE) autorefraction, axial length (AL), and choroidal thickness were performed at baseline, 1 month, 3 months, and 6 months. RESULTS: The adjusted mean SE change over the 6 months was -0.38 ± 0.04 D in the 0.01% A group (n = 50) and -0.25 ± 0.04 D in the 0.01% A + AAS group (n = 50), demonstrating a significant between-group difference (P = 0.02). There was no statistically significant difference in the change of AL and choroidal thickness between the two groups (both P > 0.05). CONCLUSIONS: Adjunctive AAS compared with 0.01% A monotherapy slowed myopic progression in Chinese children by a statistically small amount, but had no effect on axial elongation and choroidal thickness during this 6-month observation. The trial is registered with ChiCTR1900021316.