外泌体在糖尿病视网膜病变的机制研究进展

外泌体是广泛存在于人体,由机体细胞产生并分泌的纳米级细胞外囊泡,能相对稳定地存在于各种生物组织和体液中,并携带特定的miRNA、蛋白质、转录因子等多种信息分子,参与调控体内多种疾病的病理生理过程。近年来随着外泌体在各学科研究的不断深入,其在眼科学领域的研究也迅速开展,目前发现外泌体在糖尿病视网膜病变、年龄相关性黄斑变性、自身免疫性葡萄膜炎、角膜病及青光眼等多种疾病中发挥重要作用。随着生活水平的提高,全世界糖尿病视网膜病变致盲人数逐年增加,而糖尿病视网膜病变机制研究未明,近年许多研究发现外泌体在其中发挥着重要作用,本文对外泌体在糖尿病视网膜病变的发生、发展机制的最新研究进展进行综述。

Comparison of anterior section parameters using anterior segment optical coherence tomography and ultrasound biomicroscopy in myopic patients after ICL implantation

AIM：To compare the agreement of anterior chamber depth（ACD）and central vault measurements obtained by anterior segment optical coherence tomography（AS-OCT）and ultrasound biomicroscopy（UBM）of post surgical high myopic eyes with posterior chamber phakic intraocular lens（Visian ICL;STAAR Surgical）implantation.·METHODS：Fifty-two phakic eyes of 28 high myopic patients who underwent implantable Collamer lens（ICL）surgery for the correction of high myopia were studied.The postoperative ACD,the distance between the corneal endothelium and the anterior surface of ICL（cornea-ICL）and the central vault were measured with the AS-OCT system and the UBM system.Intraclass correlation coefficient（ICC）and the Bland-Altman plot were used to evaluate the repeatability and agreement of two devices.·R ESULTS：The mean ACD,cornea-ICL and central vault in the 52 phakic eyes after ICL surgery was 3.19±0.28 mm,2.47±0.28 mm,0.50±0.19 mm by AS-OCT and3.13±0.25 mm,2.49±0.25 mm,0.44±0.19 mm by UBM,respectively.Pairwise comparison of ACD and central vault measurements showed significant differences between AS-OCT and UBM（〈0.05）.However,no statistically significant difference was found between these imaging techniques in cornea-ICL（〉0.05）.The Pearson correlation coefficient（）between AS-OCT and UBM measurements for ACD,cornea-ICL and vault was0.88,0.80 and 0.89,respectively（〈0.001）.The ICC was0.89-0.94 for the measurements of AS-OCT and UBM.Bland-Altman analysis showed the 95%limits of agreement of ACD,cornea-ICL,central vault measurements between these two devices were-0.20 to 0.32 mm,-0.36to 0.32 mm and-0.12 to 0.24 mm,respectively.58·CONCLUSION：Central ACD and vault measurements using AS-OCT demonstrated a slight significantly higher value than using UBM in phakic eyes after ICL surgery.These two devices should not be used interchangeably for measurements of central ACD and vault in patients after phakic intraocular lens implantation.

Corneal flap morphological analysis using anterior segment optical coherence tomography in laser in situ keratomileusis with femtosecond lasers versus mechanical microkeratome

AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intendedfiap thickness was 110 mu m and 160 mu m respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45 degrees and 135 degrees meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43 +/- 4.70 mu m, while 125.90 +/- 17.50 mu m in the Hansatome group. The difference between the actual and the expectedfiap thickness was 5.61 +/- 3.84 mu m and 31.52 +/- 12.27 mu m, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.

Phakic posterior chamber intraocular lens for unilateral high myopic amblyopia in Chinese pediatric patients

AIM： To assess the outcomes of posterior chamber implantable collamer lens （ICL） implantation in Chinese pediatric patients with unilateral high myopic amblyopia.METHODS： Eleven eyes of 11 amblyopic patients aged 11.02±3.34y underwent ICL （model V4, Staar Surgical Inc.） implantation to treat unilateral anisometropia were studied. Visual acuity, cycloplegic refraction, contrast sensitivity, stereopsis, intraocular pressure （IOP）, vaulting, corneal endothelial cell count and complications were evaluated. Patients completed follow-up at 3d, 1, 3mo and the last follow-up time （mean 8.18±2.82mo） after surgery.RESULTS： The mean myopic anisometropia was -13.70±3.25 D preoperatively and ＋0.69±2.63 D at 8mo postoperatively. The logMAR corrected distance visual acuity （CDVA） of the amblyopic eye was 1.51±0.72 preoperatively and 0.75±0.40 at 8mo postoperatively. The logMAR CDVA at 3d, 1, 3 and 8mo postoperatively improved by a mean of 0.64, 1.55, 1.82 and 2.64 lines and gained more than 2 lines accounted for 18%, 45%, 45%, 64%, respectively. The contrast sensitivity of 0.5, 1 and 2 cpd in amblyopic eyes was significantly increased after surgery. No patient had near stereopsis recovery. The vaulting at 3 and 8mo was significantly lower than that at 1mo postoperatively. No other intraoperative or postoperative complications were observed, except an acute pupillary block glaucoma happened in a patient at two weeks postoperatively.CONCLUSION： This short-term results indicate that ICL implantation can be a promising alternative therapy for high myopic anisometropic amblyopia in pediatric patients who have failed with conventional treatments and not suitable to corneal refraction surgery.

Posterior chamber phakic intraocular lens for the correction of high myopic anisometropic amblyopia in adults

This study aims to evaluate the clinical results of posterior chamber implantable collamer lens（ICL） implantation in adults with high myopic anisometropic amblyopia. Thirteen patients aged 27.04±7.24 y（range 19.2 to 42.5） were studied. ICL implantation was performed in 13 amblyopic eyes. The mean myopic anisometropia was significantly dropped from-10.70±3.02 D preoperatively to ＋0.09±1.67 D at 1 mo postoperatively. The logMAR CDVA at 3 d, 1, 3 and mean 9 mo postoperatively improved by a mean of 1.69, 2.50, 3.01 and 3.00 lines and gained more than 2 lines accounted for 23.08%（3 eyes）, 41.67%（5 eyes）, 63.63%（7 eyes） and 55.56%（5 eyes）, respectively. The contrast sensitivity of amblyopic eyes was significantly increased after surgery. Four patients partially recovered near stereopsis（400＂ to 100＂）. There was no severe complications were observed. ICL implantation alone can improve vision, contrast sensitivity, and partial restoration of binocular vision in adult patients with high myopic anisometropia.

Investigation of children’s habits of smartphone usage and parental awareness of myopia control in underdeveloped areas of China

AIM: To investigate the behaviors of smartphone usage and parental knowledge of vision health among primary students in the rural areas of China. METHODS: In this school-based, cross-sectional study, a total of 52 606 parents of students from 30 primary schools in the Xingguo County were investigated through an online questionnaire from July 2020 to August 2020. The self-designed questionnaire contained three parts: the demographic factors of both children and parents, parental knowledge and attitude toward myopia, and the preventive treatment of myopia.RESULTS: A total of 52 485 appropriately answered questionnaires were received, showing an effective response rate of 95.1%. The average age of the primary students was 10.1±0.98 y and the prevalence of myopia among the primary students was 40.3%. The age of myopia occurrence in elementary students was significantly correlated with the parents’ educational level(95%CI: 0.82-0.98, P=0.013), children’s gender(95%CI: 1.08-1.20, P<0.001), school location(county or countryside)(95%CI: 0.59-0.66, P<0.001), children’s smartphone ownership(95%CI: 1.09-1.26, P<0.001), and the average time spent on smartphone per day(95%CI: 0.78-0.88, P<0.001). School location in the county town, high family income, and high parents’educational level significantly affected both parents’ myopia awareness and children’s vision-threatening behaviors(P<0.01). Left-behind children showed a higher incidence of vision-threatening habits than those who lived with their parents(P<0.01).CONCLUSION: The results reveal the current situation of myopia development among rural primary school students and their parents. This survey will serve as a guidance for designing myopic prevention policies in the rural areas of China.

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.

Composite Hierachical Linear Quantile Regression

Multilevel （hierarchical） modeling is a generalization of linear and generalized linear modeling in which regression coefficients are modeled through a model, whose parameters are also estimated from data. Multilevel model fails to fit well typically by the use of the EM algorithm once one of level error variance （like Cauchy distribution） tends to infinity. This paper proposes a composite multilevel to combine the nested structure of multilevel data and the robustness of the composite quantile regression, which greatly improves the efficiency and precision of the estimation. The new approach, which is based on the Gauss-Seidel iteration and takes a full advantage of the composite quantile regression and multilevel models, still works well when the error variance tends to infinity, We show that even the error distribution is normal, the MSE of the estimation of composite multilevel quantile regression models nearly equals to mean regression. When the error distribution is not normal, our method still enjoys great advantages in terms of estimation efficiency.