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Introducción: La córnea constituye el elemento más importante del sistema óptico, al ser el primer medio transparente del ojo; tiene la finalidad de mejorar la calidad de la imagen que se forma en la retina, por lo que su transparencia es imprescindible para poder obtener una buena agudeza visual. Cuando sus capas están afectadas por diferentes enfermedades, se requiere sustituir este tejido dañado; este procedimiento, denominado trasplante de córnea o queratoplastia, tiene diferentes finalidades. Objetivo: Caracterizar los resultados de la cirugía de trasplante de córnea tras diez años del primer procedimiento quirúrgico en la provincia de Villa Clara. Métodos: Se realizó un estudio observacional descriptivo longitudinal retrospectivo, con una muestra de 204 pacientes operados de trasplante de córnea en el Hospital Universitario Clínico-Quirúrgico «Arnaldo Milián Castro» de Villa Clara, en el período comprendido entre 2008 y 2018. Las variables estudiadas fueron: sexo, finalidad del procedimiento, diagnóstico y complicaciones. Resultados: Predominó el sexo masculino (53,4 %); la finalidad más frecuente del trasplante tuvo fines ópticos (85,8 %); principal diagnóstico: la queratopatía bullosa (42,7 %); dentro de las complicaciones más frecuentes estuvieron: el rechazo al injerto, el defecto epitelial y el glaucoma secundario. Conclusiones: La cirugía de trasplante de córnea en la provincia de Villa Clara significa un gran avance en el desarrollo y perfeccionamiento para el tratamiento de múltiples afecciones corneales. Los diagnósticos más frecuentes fueron: la queratopatía bullosa y las opacidades corneales; las complicaciones más frecuentes, el rechazo al injerto, la aparición de defectos epiteliales y el glaucoma secundario.
Introduction: the cornea constitutes the most important element of the optical system, being the first transparent medium of the eye; its purpose is to improve the quality of the image that is formed on the retina, so its transparency is essential to obtain good visual acuity. When its layers are affected by different diseases, it is required to replace this damaged tissue; this procedure called cornea transplant or keratoplasty has different purposes. Objective: to characterize the results of corneal transplant surgery ten years after the first surgical procedure in Villa Clara province. Methods: a retrospective, longitudinal, descriptive and observational study was carried out with a sample of 204 patients who underwent corneal transplant surgery at "Arnaldo Milián Castro" Clinical and Surgical University Hospital in Villa Clara between 2008 and 2018. Age, purpose of the procedure, diagnosis and complications were the variables studied. Results: male gender predominated (53.4%); the most frequent purpose of the transplant was for optical purposes (85.8%); bullous keratopathy (42.7%) was the main diagnosis as well as, graft rejection, epithelial defect and secondary glaucoma were among the most frequent complications. Conclusions: corneal transplant surgery in Villa Clara province means a great advance in the development and improvement for the treatment of multiple corneal conditions. The most frequent diagnoses were bullous keratopathy and corneal opacities; graft rejection, the appearance of epithelial defects and secondary glaucoma were the most frequent complications.
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Cornea , Corneal Transplantation , Corneal DiseasesABSTRACT
AIM:To evaluate corrective effect and stability of corneal morphology in patients with moderate to high myopia after 2a treatment of femtosecond laser assisted laser in situ keratomileusis(FS-LASIK)Xtra.METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P<0.01), and there was no difference in UCVA and SE between the two groups(P>0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P<0.05). There were differences in corneal curvature on the surface of different diameter areas(3, 5, and 7 mm)between the two groups at 3 mo, 1, and 2 a postoperatively compared with preoperatively. After 1 and 2 a postoperatively, the corneal posterior surface curvature of the FS-LASIK Xtra group with corneal diameter of 3 and 5 mm was higher than that of the FS-LASIK group(P<0.05).CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.
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AIM: To explore the accuracy of the ratio of axial length(AL)to the average corneal radius(CR)(AL/CR value, i.e., axial ratio)in assessing myopia in children and adolescents.METHOD:Cross-sectional study. A total of 340 cases(680 eyes)of children and adolescents aged 4-16 years old were collected from the ophthalmology clinic of Shangyu People's Hospital of Shaoxing between January 2022 and October 2022. All patients were subjected to optometry after cycloplegia to obtain spherical equivalent(SE), check and record the patient's AL, average CR, and calculate the AL/CR value.RESULTS:All subjects in this study underwent optometry after cycloplegia, and a total of 609 eyes(89.6%)were found to have myopia(SE≤-0.50 D), 58 eyes(8.5%)with hyperopia(SE≥+0.50 D)and 13 eyes(1.9%)with emmetropia(-0.50 D>SE>+0.50 D). There was a statistically significant difference in SE, AL and AL/CR values among different refractive states(P<0.01), but there was no difference in CR(P>0.05). All subjects have refractive parameters: SE +8.75--8.75(average -2.25±2.38)D; AL 19.91-27.54(average 24.41±1.22)mm; CR 7.17-8.71(average 7.83±0.27); AL/CR values range from 2.50-3.50(average 3.12±0.14), correlation analysis showed a relative strong negative correlation between SE and AL/CR and AL(r=-0.891, P<0.01; r=-0.758, P<0.01), but no significant correlation between SE and CR(r=0.067, P>0.05), there was a positive correlation between AL and CR(r=0.483, P<0.01). The linear relationships between SE and AL/CR, AL were SE=45.026-15.162×AL/CR, R2=0.794, SE=33.741-1.474×AL, R2=0.574, respectively. The gold standard was based on the optometric results of cycloplegia, the sensitivity, specificity, misdiagnosis rate and missed diagnosis rate of AL/CR value for myopia were 0.962, 0.839, 0.169, 0.038, respectively, and the accuracy was 94.85%, the Kappa coefficient was 0.742, and the area under the ROC curve was 0.972.CONCLUSION:With high qualitative diagnostic value for myopia and a certain clinical significance for myopia monitoring, AL/CR value can be used to guide myopia prevention and control and other related ophthalmic clinical work.
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Corneal visualization Scheimpflug technology(Corvis ST)is currently the most commonly used clinical device for assessing in vivo corneal biomechanics. The new parameter stress-strain index(SSI)has been a hot topic of clinical research in recent years, which not only directly reflect corneal biomaterial stiffness, but also closely correlates with the progression of certain diseases. SSI was generated based on the predictions of corneal behavior using finite element(FE)numerical modeling to simulate the effects of intraocular pressure and Corvis ST jets. The SSI algorithm does not change with central corneal thickness(CCT), intraocular pressure, or biomechanically corrected intraocular pressure(BIOP), but it is clearly associated with altered collagen fibres in the corneosclera. The principles of SSI, the relationship between age and SSI, the relationship between axial length and SSI, the relationship between myopia and SSI, and the application of SSI are summarized and concluded.
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Keratoconus is a progressive blinding eye disease that characterized by corneal thinning and protrusion, which accompanied with irregular astigmatism and impaired visual acuity.The irregular astigmatism of early keratoconus can be corrected by spectacles. For the irregular astigmatism of moderate to severe keratoconus, spectacles are no longer suitable, and contact lenses are the best choice for patients to restore vision. There are various types of contact lenses, making the selection very difficult. In addition, trying on lenses for a long time will increase the discomfort and overall feeling of patients, and greatly increase the workload of doctors. Thus, the article aims to summarize and discuss the classification of contact lenses, the application of contact lenses in different types of keratoconus, the complications of contact lens, and the current status and prospect of contact lenses, with a view to understanding the management and clinical application of contact lenses in keratoconus patients and to further improving the application value of contact lenses in keratoconus.
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Neurotrophic keratitis(NK)is a degenerative corneal disease caused by impairment of trigeminal innervations. It can lead to spontaneous corneal epithelial defects, corneal ulceration and perforation. Early diagnosis of NK is crucial and requires accurate investigation of clinical history and thorough examination of ocular surface to determine clinical stage. Treatment for NK needs to be divided into stages according to disease severity. In addition to conventional treatments including artificial tears, blepharorrhaphy, and amniotic membrane transplantation, there are also emerging treatments such as targeted drug therapy and corneal neurotization. This article summarized the epidemiology, clinical manifestations and classification, etiology, diagnosis, differential diagnosis and treatment of NK, aiming to provide reference for the early diagnosis and treatment of NK in the future.
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AIM: To investigate the potential of human induced pluripotent stem cells(hiPSCs)differentiating into corneal epithelial cells in the simulated limbal stem cells(LSCs)microenvironment.METHODS: The hiPSC cell lines were established in vitro, and hiPSCs were co-cultured with corneal stromal cells in transwell system, which simulated the LSC microenvironment. Bone morphogenetic protein 4(BMP4)and a specific transforming growth factor β inhibitor(SB431542)were added to improve the differentiation efficacy. The expression of corneal epithelial cell-specific markers CK3 and CK12, corneal epithelial cell precursor CK15, and the limbal stem cell markers ABCG5 were determined by immunofluorescence staining and flow cytometry.RESULTS: The hiPSCs were actively proliferated in vitro, and immunofluorescence staining showed positive stem cell-specific markers OCT4, SOX2, TRA-1-60 and NANOG. Furthermore, hiPSCs co-cultured with corneal stromal cells exhibited LSCs markers ABCG5 and corneal epithelial cell precursor markers CK15 were positive; however, corneal epithelial cell markers CK3 and CK12 were negative. With the addition of BMP4 and SB431542, hiPSCs showed positive expression of CK3, and the CK3 expression increased over the time.CONCLUSION: With the addition of SB431542 and BMP4, hiPSCs cultured in simulated LSCs microenvironment could differentiate into corneal epithelial cells.
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AIM:To compare the differences of ocular biometric parameters of age-related cataract between Tibetan and Han ethnic groups, and to analyze the distribution characteristics of ocular biometric parameters in Tibetan cataract patients.METHODS:Retrospective cohort study. A total of 661 patients(1 030 eyes)with age-related cataract confirmed in the hospital between January 2019 and December 2020 were enrolled. The parameters of axial length, anterior chamber depth, keratometry, corneal astigmatism and astigmatic axis were measured by IOL Master 500 in 483 cases(739 eyes)of Tibetan age-related cataract patients and 178 cases(291 eyes)of Han patients.RESULTS:The axial length, anterior chamber depth and corneal astigmatism of the Tibetan patients with age-related cataract were 23.33(22.81, 23.86)mm, 3.04(2.79, 3.30)mm and 0.73(0.47, 1.07)D. The mean keratometry was 43.89±1.35 D. The results indicated that Tibetan cataract patients had shorter axial lengths and smaller keratometry compared to Han patients(all P<0.05). Age in Tibetan patients was negatively correlated with axial length and anterior chamber depth, and positively correlated with keratometry(all P<0.05). Tibetan male patients had longer axial lengths, deeper anterior chambers, and flatter corneas compared to female patients(all P<0.05).CONCLUSION:There were differences in ocular biometric parameters between age-related cataract patients of Tibetan and Han ethnicities. The distribution of ocular biometric parameters in Tibetan cataract patients varied across different age groups and gender groups.
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AIM: To explore the synthesis of thermo-sensitive poly N-isopropylacry-lamide(PNIPAAm)and the petri dish grafted with PNIPAAm hydrogels by the electron accelerator, as well as the growth conditions and the biological characteristics of rabbit corneal stromal cells on thermo-sensitive PNIPAAm hydrogels, and the cell sheets obtained from the PNIPAAm hydrogels.METHODS: NIPAAm monomer was dissolved in 2-propanol at concentrations of 55% with 0.5% N,N'-Methylenebisacry-lamide(MBA). Solution(70 μL)was added and spread uniformly over 35 mm petri dish. These dishes were immediately subjected to irradiation. After follow-up treatment, rabbit corneal stromal cells were cultured on thermo-sensitive petri dish in vitro.RESULTS: According to the monomer formula and radiation synthesis scheme in this experiment, PNIPAAm can be synthesized on the surface of the petri dish. Rabbit corneal stromal cells grew well in the thermo- sensitive surface and can be separated into sheets.CONCLUSION: The single and multilayer carrier-free cell sheets can be obtained from the use of thermo-sensitive petri dish.
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In vivo confocal microscopy of the cornea is a non-invasive, rapid, and comprehensive technique for real-time, dynamic observation of all layers of the cornea. Confocal microscopy allows the examination of the morphology and cell density in the different layers of the cornea through direct visualization. With the increasing prevalence of diabetes, ocular complications have become common and have garnered more interest and in-depth research from clinical and scientific communities. This paper provides a comprehensive review of research progress made using in vivo confocal microscopy to observe various layers of cornea tissue in diabetic patients.
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ObjectiveTo provide a reference for the establishment of an ideal corneal neovascularization （CNV） animal model by summarizing the modeling characteristics of CNV animal models. MethodWith "CVN" as the theme word， this paper searched the China National Knowledge Infrastructure （CNKI）， Wanfang， Chinese medical journals full-text database， and PubMed database and screened out relevant literature on CNV animal experiments from 2013 to 2023. The database was established by Excel 2021， and the experimental animal strain， gender， modeling method， detection index， and application category were sorted out. The characteristics of the CNV animal model were analyzed. ResultAfter comparative analysis， it was found that the animal strains were Sprague-Dawley rats （87 times， 29.49%） and New Zealand white rabbits （52 times， 17.63%）. Male animals were recommended. Most modeling methods for efficacy verification and mechanism studies were the alkali burn method. Index detection methods included apparent index observation， histopathological detection， immunohistochemistry （IHC）， Western blot， and various polymerase chain reaction （PCR） tests. Detection indexes included apparent indication， corneal histopathology， CNV regulation， etc. ConclusionThe CNV model of SD rats induced by the alkali burn method is recommended for model replication， and the indexes are mainly selected from the growth of CNV， corneal histopathological test， and vascular endothelial growth factor （VEGF）-related test. In addition， according to the demand， the corneal apparent indication and the basic indexes related to the regulation of CNV， such as vascular endothelial growth factor receptor 2 （VEGFR2）， basic fibroblast growth factor （bFGF）， and secretogranin Ⅲ （Scg3） are also selected. Clinical treatment of CNV relies on anti-inflammatory drugs and anti-VEGF drugs， and there is a lack of application of traditional Chinese medicine （TCM）， so the model needs to be improved by adding elements of TCM syndromes.
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AIM: To explore the clinical effect of small incision lenticule extraction(SMILE)on the treatment of myopic anisometropia.METHODS: Clinical data of 76 patients(146 eyes)with myopic anisometropia who received SMILE or femtosecond assisted laser in situ keratomileusis(FS-LASIK)in our hospital from January 2021 to December 2022 were retrospectively analyzed. The patients were divided into SMILE group(39 cases, 77 eyes)and FS-LASIK group(37 cases, 69 eyes)according to surgical methods. Uncorrected visual acuity(UCVA), diopter, anisometropia, corneal aberration and occurrence of postoperative complications were compared between the two groups at 1 wk, 1 and 3 mo after surgery.RESULTS: The UCVA of the two groups was improved after surgery compared with that before surgery, and the coma, trefoil, spherical aberration and total higher-order aberration were significantly increased compared to those before surgery(P<0.05), and the coma, trefoil, spherical aberration and total higher-order aberration in the FS-LASIK group were significantly higher than those in the SMILE group(P<0.05). After follow-up to 3 mo after surgery, the incidence of postoperative complications was significantly lower in the SMILE group than that in the FS-LASIK group(5.2% vs 15.9%, P<0.05).CONCLUSION: Both SMILE and FS-LASIK can effectively enhance the UCVA and improve the visual quality in patients with myopic anisometropia, but SMILE has lower corneal higher order aberrations, lower incidence of postoperative complications and better overall effect.
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AIM: To evaluate the clinical efficacy of corneal stromal lenticule-combined accelerated transepithelial corneal collagen cross-linking(SC-A-TE-CXL)in the treatment of severe keratoconus.METHODS: Prospective before-after self-control study. A total of 10 cases(14 eyes)of severe keratoconus with the thinnest corneal thickness(including epithelium)less than 400 μm were collected from March 2019 to July 2022 at the ophthalmology department of Affiliated Eye Hospital of Nanjing Medical University. Among them, 8 males(12 eyes)and 2 females(2 eyes)were treated with SC-A-TE-CXL. Corneal curvature, uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), the thinnest corneal thickness(TCT), central corneal thickness(CCT), non-contact intraocular pressure, endothelial cell density(ECD)and anterior or posterior elevations at the thinnest point before surgery and at 1, 3, 6 and 12 mo postoperatively were observed and recorded, as well as corneal cross-linking depth at 1 mo postoperatively.RESULTS: UCVA and BCVA at 1, 3, 6, and 12 mo after SC-A-TE-CXL were higher than those preoperatively, but there were no differences(F=0.793, P=0.535; F=0.783, P=0.542). K1, K2, Km and Kmax decreased at each time point postoperatively compared with those preoperatively, but there were no differences(F=0.627, P=0.574; F=1.264, P=0.296; F=0.727, P=0.520; F=1.115, P=0.359). Anterior and posterior elevations at the thinnest point both decreased compared with those preoperatively, but the differences were not statistically significant(F=1.046, P=0.359; F=1.164, P=0.337). The non-contact intraocular pressure at each time point postoperatively was higher than that preoperatively, but the differences were not statistically significant(F=0.814, P=0.522). There were no differences in CCT and TCT at any time points of the follow-ups compared with those preoperatively(F=0.931, P=0.453; F=0.782, P=0.542). There was no difference in ECD at 12 mo postoperatively versus preoperative value(t=1.266, P=0.228). At 1 mo postoperatively, anterior segment optical coherence tomography(AS-OCT)exhibited an increase of density in the anterior stroma, and there was a demarcation line with an average depth of 124.07±25.13 μm.CONCLUSION: SC-A-TE-CXL can be considered as a surgical treatment for severe keratoconus, which can delay the progression of severe keratoconus with high safety. However, the long-term efficacy of this treatment requires further observation.
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AIM:To investigate the effect of small incision lenticule extraction(SMILE)on the treatment of myopia patients, and the impact on corneal biomechanics.METHODS:Retrospective study. A total of 120 myopic patients(240 eyes)who were scheduled to undergo corneal refractive surgery in Anyang Eye Hospital from January 2020 to December 2021 were selected. The patients were divided into SMILE group(64 patients, 128 eyes)and transepithelial photorefractive keratectomy(TransPRK)group(56 patients, 112 eyes)according to the surgical treatment method. The two groups were compared in terms of uncorrected visual acuity, corneal biomechanics, corneal endothelial cell count, posterior corneal surface height and corneal surface regularity index at 1, 7 d, 1, 3, 6 mo and 1 a after surgery, and surgical complications.RESULTS:The uncorrected visual acuity of the SMILE group at 1, 7 d and 1 mo after surgery was better than that of the TransPRK group(all P<0.001), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P>0.05). Compared with preoperative values, corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in both groups showed a first decreasing and then increasing trend after surgery. The corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in the SMILE group at 1, 7 d and 1 mo after surgery were higher than those in the TransPRK group(all P<0.05), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P>0.05). There were no significant changes of corneal endothelial cell count and corneal posterior surface height in the two groups after surgery(all P>0.05). Furthermore, corneal surface regularity index of the two groups showed a first increasing and then decreasing trend after surgery, with no statistically significant difference between the groups(P>0.05), and there was no statistically significant difference in the incidence of postoperative complications between the groups(P>0.05).CONCLUSION:Compared with TransPRK, SMILE has less influence on corneal biomechanics, and better visual recovery in the early stage. There is no difference in long-term visual acuity between the two surgeries, and both have good safety and effectiveness.
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AIM: To compare the anterior and posterior corneal astigmatism and total refractive astigmatism before and after MyoRing implantation in keratoconus(KCN)patients.METHODS: In this historical cohort study, the preoperative and postoperative total refractive, anterior and posterior corneal astigmatism of KCN patients implanted with a 360-degree full-ring implant(MyoRing)were compared before and after four consecutive follow-up sessions at 3, 6, 9, and 12 mo after surgery.RESULTS: The study encompassed 79 KCN patients(85 eyes), comprising 43 males and 36 females. The mean age of the patients was 29±7.41 years, ranging from 17 to 48 years. Throughout the follow-up sessions, a gradual decrease was observed in the trend of changes for total refractive astigmatism, anterior corneal astigmatism, and posterior corneal astigmatism. Postoperatively, total refractive astigmatism measurements exhibited a significant decrease of 2.09 D at 12 mo after MyoRing implantation(4.27±3.15 vs 2.18±1.63 D, P<0.001). Additionally, post-operative measurements revealed an enhancement of approximately 3.20 D and 0.59 D for anterior and posterior corneal astigmatism, respectively [6.40±1.90 vs 3.20±1.75 D for anterior corneal astigmatism(P<0.001)and 1.30±0.55 vs 0.71±0.35 D for posterior corneal astigmatism(P<0.001)].CONCLUSION: MyoRing implantation demonstrates significant improvements in astigmatism parameters, encompassing total refractive astigmatism as well as anterior and posterior corneal astigmatism.
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Objective@#To explore the pattern of change of axial length/curvatrue radius ratio (AL/CR) and associated factors in primary and secondary school students in Yunnan, so as to provide scientific basis and prospective guidance for early myopia intervention and control.@*Methods@#A total of 685 students from grades 2 to 3 and grade 7 in 2 cities/counties in Yunnan Province were selected by multi stage stratified random cluster sampling method in 2020. All the participants were followed up twice with questionnaire of myopia related factors, uncorrected distance visual acuity, and refractive parameter measurement from October,2021 and March,2023,respectivelty. The distribution and change of AL/CR in different classes and groups were analyzed, and the influencing factos of AL/CR cumulative progression were explored using generalized linear model.@*Results@#AL/CR ratio in primary school students was (2.95±0.09) at baseline, increased to (2.99±0.11) at the first follow up and (3.04±0.12) at the second follow up. AL/CR ratio in middle school students(3.08±0.13) at baseline, increased to (3.12±0.15) at the first follow up and (3.15±0.14) at the second follow up. The generalized linear model showed that after controlling for environmental factors, ethnicity ( β =-0.017) , cumulative progression of the SE ( β =-0.027) influenced the changes of AL/CR ratio among the primary school students, whereas the changes of AL/CR ratio were associated with baseline AL ( β =-0.005), baseline corneal curvatrue radius ( β =0.032) and cumulative progression of SE( β =-0.035) among middle school students ( P <0.05).@*Conclusions@#The AL/CR ratio of primary and secondary school students in Yunnan can be used to judge different refractive status types, but its variation is not only related to SE progression, but also affected by different ethnic groups and baseline ocular biological parameters. so the value of AL/CR application in assessing the progression of myopia needs to be further confirmed.
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AIM: To evaluate the convenience and accuracy of a novel smartphone-assisted “any-point two-step method” for finding the target axial position in cataract phacoemulsification combined with intraocular lens(IOL)implantation.METHODS: Prospective observational study. A total of 62 cases(62 eyes)of patients with age-related cataracts who underwent cataract phacoemulsification combined with IOL implantation in our hospital from October 2021 to April 2022 were selected. They were randomly divided into two groups: 31 cases(31 eyes)in the control group were applied with the “traditional two-step method” using slit lamp to mark the target axial position of the IOL, and 31 cases(31 eyes)in the experimental group were applied with the smartphone-assisted “two-step method” to mark the target axial position of the IOL. The Callisto eye navigation system was used as a standard reference, and the deviation of the reference marking point(deviation-1), the deviation of the target axial marking point(deviation-total), and the deviation of the angle from the reference marking point to the target axial marking point(deviation-2)were calculated and recorded as the preoperative axial marking time.RESULTS:Both deviation-1 and deviation-total values were lower in the experimental group than those in the control group(1.06°±1.39° vs 2.48°±2.23°, 1.77°±1.54° vs 2.81°±1.58°, all P<0.01), but there was no significant difference in the deviation-2 values between the two groups(1.35°±1.40° vs 1.48°±1.79°, P>0.05). The preoperative axial marking took shorter time in the experimental group than in the control group(1.77±1.70 min vs 2.88±3.20 min, P<0.01).CONCLUSION: The smartphone-assisted “any-point two-step method” for finding the target axial position in cataract phacoemulsification combined with IOL implantation is simple, time-saving, and accurate compared with the “traditional two-step method”.
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AIM: To observe and analyze the effectiveness and safety of wearing corneal refractive therapy(CRT)and vision shaping treatment(VST)designed orthokeratology in controlling myopic progression in adolescents with low E-value corneal morphology.METHODS: This prospective study involved 100 cases(100 eyes)of adolescent myopia patients fitted with orthokeratology at our optometry clinic from January 2020 to December 2021. The data of right eye were collected for research, and they were divided into low myopia group(-1.00 to -3.00 D)and moderate myopia group(-3.25 to -5.00 D)according to spherical equivalent, with 50 cases in each group. Each group of patients was further randomly divided into the CRT group and the VST group, with 25 cases in each group. Uncorrected visual acuity, refractive error, axial length(AL), tear film break-up time(BUT), corneal endothelial cell density, corneal staining grading, lens decentration, and refractive power at 15°-30° were measured before and after wearing orthokeratology, with a follow-up duration of 1.5 a.RESULTS: The uncorrected visual acuity of CRT and VST subgroups in the low myopia group showed no statistical significance at any time point after wearing orthokeratology. However, in the moderate myopia group, CRT subgroup showed better uncorrected visual acuity than the VST subgroup, with significant differences at 1 d and 1 wk(t=-9.474, -12.067, both P<0.01); no significant differences were noted at other time points. After wearing lens for 6 mo and 1.5 a, the AL growth for the CRT subgroup in low and moderate myopia was less than the VST subgroup, with no statistically significant differences. There were no statistically significant differences in binocular BUT and corneal endothelial cell density after wearing lens for 6 mo and 1.5 a. Corneal injury was lower in the CRT subgroup than that in the VST subgroup, but the difference was not statistically significant(Z=-1.803, P=0.071). Lens decentration was significantly better in the CRT subgroup than in the VST subgroup(Z=-4.629, P<0.001). In the periphery of the retina at 15°-30°, there were no significant differences in the amount of myopic defocus between the two groups, while it was statistically significant at 1, 3, and 6 mo in the moderate myopia subgroup(t=-3.949, P=0.008; t=-5.833, P<0.001; t=-6.231, P<0.001), indicating that CRT subgroup could produce a greater amount of myopic defocus.CONCLUSION: For patients with low E-value corneal morphology, CRT, using the vector height at 8 mm on the cornea for fitting, is not limited to the corneal E-value. It shapes faster and improves uncorrected visual acuity after shaping, especially for moderate myopia, achieving better daytime vision. In terms of controlling myopia, CRT fitting elevates return zone depth(RZD), creating a small central optical zone to produce more peripheral myopic defocus. However, there was no significant difference between the two groups in controlling AL growth. Both groups showed minimal corneal damage, indicating consistent safety in myopia control.
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Corneal stroma is a significant part of the cornea and plays a significant role in the eye's refractive system. Although corneal transplantation is now the most effective treatment for corneal stromal disease, its advancement has been constrained by a shortage of donors, the need for prolonged immunosuppressive medicine to prevent rejection, and low graft survival rates. An alternate strategy is to use the corneal stroma's natural capacity for regeneration to create the ideal conditions for the collagenous extracellular matrix of the stroma to self-renew. However, it is challenging to replicate the intricate ultrastructure of the corneal stroma in vitro. Regenerative medicine has so been used to address these issues. These approaches refer to numerous disciplines, including stem cell-induced differentiation, tissue engineering and gene editing. This article provides potential directions for the future clinical applications of corneal stromal regeneration and repair while summarizing pertinent techniques, research progress, and issues.
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Keratoconus is a chronic non-inflammatory corneal disease characterized by thinning and localized protrusion of the corneal stroma in a conical shape. It often leads to irreversible irregular astigmatism and varying degrees of decline in corrected visual acuity. With the rise of femtosecond laser refractive surgery, corneal lenses were discovered as a good biological material. Corneal lens implantation of the cornea can increase the thickness of the cornea and delay the progression of keratoconus disease for further treatment. Currently, convex lenses obtained from myopic small incision lenticule extraction(SMILE)surgery and concave lenses obtained from farsighted SMILE surgery, as well as parallel lenses obtained from donors, can be implanted into the cornea with the aid of femtosecond lasers as lens materials. This article will summarize and discuss the above three lens material implantation methods to provide reference for the selection of keratoconus treatment.