AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopi...AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.展开更多
Dry eye disease(DED)is a multifactorial disorder that disturbs ocular surface equilibrium,considerably diminishing quality of life.Present therapies only offer symptomatic alleviation.Stem cell treatment,especially me...Dry eye disease(DED)is a multifactorial disorder that disturbs ocular surface equilibrium,considerably diminishing quality of life.Present therapies only offer symptomatic alleviation.Stem cell treatment,especially mesenchymal stem cells(MSCs),has surfaced as a viable approach for tissue regeneration and immunological regulation in DED.Preclinical and early clinical investigations indicate that MSCs can improve lacrimal gland functionality,diminish inflammation,and facilitate corneal regeneration.Nonetheless,obstacles persist in enhancing MSC viability,determining the optimal MSC source,and guaranteeing sustained therapeutic effectiveness.Additional extensive randomized clinical trials are required to confirm the efficacy of MSC-based therapies for severe DED.展开更多
Diabetic corneal neuropathy and diabetic retinopathy are ocular complications occurring in the context of diabetes mellitus.Diabetic corneal neuropathy refers to the progressive damage of corneal nerves.Diabetic retin...Diabetic corneal neuropathy and diabetic retinopathy are ocular complications occurring in the context of diabetes mellitus.Diabetic corneal neuropathy refers to the progressive damage of corneal nerves.Diabetic retinopathy has traditionally been considered as damage to the retinal microvasculature.However,growing evidence suggests that diabetic retinopathy is a complex neurovascular disorder resulting from dysfunction of the neurovascular unit,which includes both the retinal vascular structures and neural tissues.Diabetic retinopathy is one of the leading causes of blindness and is frequently screened for as part of diabetic ocular screening.However,diabetic corneal neuropathy is commonly overlooked and underdiagnosed,leading to severe ocular surface impairment.Several studies have found that these two conditions tend to occur together,and they share similarities in their pathogenesis pathways,being triggered by a status of chronic hyperglycemia.This review aims to discuss the interconnection between diabetic corneal neuropathy and diabetic retinopathy,whether diabetic corneal neuropathy precedes diabetic retinopathy,as well as the relation between the stage of diabetic retinopathy and the severity of corneal neuropathy.We also endeavor to explore the relevance of a corneal screening in diabetic eyes and the possibility of using corneal nerve measurements to monitor the progression of diabetic retinopathy.展开更多
The cornea is a transparent tissue that serves as the main refractive element of the eye ball.Limbal epithelial stem cells(LESCs),residing in the basal epithelial layer of the Palisades of Vogt located in the corneal ...The cornea is a transparent tissue that serves as the main refractive element of the eye ball.Limbal epithelial stem cells(LESCs),residing in the basal epithelial layer of the Palisades of Vogt located in the corneal limbus between cornea and scleral,are believed to be crucial for the continuous turnover of the corneal epithelium.The proliferation,migration,and differentiation of the LESCs are modulated by unique physical and chemical futures contained within the microenvironment known as the limbal niche.This niche,composed of nerve terminals,cells,extracellular matrix,vasculature,and signaling molecules,is the home for processes such as proliferation,migration and differentiation.Corneal nerve terminals possess special anatomical structures in the limbal region and basal epithelial cells,and they demonstrate pivotal biological effects in the regulation of the LESC function and corneal epithelium homeostasis.Biological molecules such as neuropeptides,neurotransmitters,and neurotrophic factors play a crucial role in modulating the LESCs phenotype responsible for corneal epithelium homeostasis.This paper will review recent studies on how these nerve derived molecules function in this process and provide clear orientations for future research.展开更多
Background:Fluorescein is commonly used in ophthalmology for the assessment of ocular surface integrity.There have been limited studies on the effects of fluorescein on corneal endothelial cells.This study aims to ass...Background:Fluorescein is commonly used in ophthalmology for the assessment of ocular surface integrity.There have been limited studies on the effects of fluorescein on corneal endothelial cells.This study aims to assess the effect of the widely used fluorescein dye on human corneal endothelial cells(HCEnCs)in vitro at different concentrations and exposure times.Methods:B4G12,an immortalized human corneal endothelium cell line was cultured on pre-coated tissue culture flask with human endothelial-serum free medium(SFM)supplemented with 10 ng/mL basic fibroblast growth factor(bFGF).The fully confluent B4G12 cell monolayers in 96 well plates were treated with water as control,or fluorescein at various concentrations and exposure times.Cell viability was assessed using two techniques:Alamar Blue assay and cell morphology assessment with an inverted phase-contrast microscopy.Results:Short-term exposure to fluorescein(0.01-0.2%)for up to 30 minutes did not affect cell viability.Continuous fluorescein exposure however significantly reduced the viability of the cells with a notable reduction in cell metabolic activity with fluorescein treatments of 0.001%,0.01% and 0.05% for 1 day(and up to 4 days).Conclusions:Short-term exposure to fluorescein for up to 30 minutes in concentrations commonly used in clinical practice did not affect HCEnC viability.However,fluorescein exposure for longer durations can be detrimental to corneal endothelial cell health.Future studies should evaluate the effects of longer-term fluorescein exposure on endothelial function especially in susceptible patients including the elderly and patients with epithelial defects that enable diffusion of fluorescein towards the endothelium.展开更多
AIM:To assess tomographic changes and subclinical edema detection in Fuchs’endothelial corneal dystrophy(FECD)through Scheimpflug tomography in a group of phakic patients contemplating cataract surgery.METHODS:A retr...AIM:To assess tomographic changes and subclinical edema detection in Fuchs’endothelial corneal dystrophy(FECD)through Scheimpflug tomography in a group of phakic patients contemplating cataract surgery.METHODS:A retrospective study was conducted on 30 phakic eyes from patients diagnosed with FECD but without clinical edema,and 59 phakic eyes from a control group without corneal alterations.Comprehensive ophthalmic examinations were conducted,including slitlamp biomicroscopy,corneal specular microscopy(CSM),and Scheimpflug tomography.RESULTS:The study encompassed 30 phakic eyes with FECD(mean age 59.8±13.1y)and 59 control eyes(mean age 61.3±7.7y).The best-corrected visual acuity was higher in the control group compared to the FECD group[0(0,0.08)vs 0.05(0,0.15)logMAR;P=0.042].CSM revealed significant differences between the FECD and control groups in several parameters:number of analyzed cells(26±13 vs 135±42,P<0.001),cell density(2049±376 vs 2479±225 cells/mm2,P<0.001),mean cell area[463(434,544)vs 397(383,431)μm2;P<0.001],coefficient of variation(54.8%±18.7%vs 41.0%±7.2%,P<0.001),and hexagonal cells[0(0,47%)vs 47%(40%,53%),P<0.001].Although often used as a clinical parameter for detecting edema,central corneal thickness measured by CSM showed no significant difference between the FECD and control groups(530±57 vs 546±30μm,P=0.179).Significant differences were noted in various Pentacam measurements between the groups.Specifically,parameters like loss of parallel isopachs(13 vs 0 eyes,P<0.001),displacement of the thinnest point(11 vs 0 eyes,P<0.001),posterior focal depression(25 vs 7 eyes,P<0.001),and increased light scatter[21.4(17.6;23.9)vs 18.0(16.8,21.8),P=0.01]were significantly more prevalent in FECD eyes,reflecting the presence of subclinical edema and loss of corneal transparency.CONCLUSION:Scheimpflug tomography allows for an objective assessment of FECD,offering the capability to detect subclinical edema at an early stage,monitor disease progression,and serve as a predictor of corneal decompensation following cataract surgery.展开更多
AIM:To investigate the changes in posterior corneal elevation within 6mo after small incision lenticule extraction(SMILE)surgery for myopia and myopic astigmatism in patients with thin corneas.METHODS:A prospective st...AIM:To investigate the changes in posterior corneal elevation within 6mo after small incision lenticule extraction(SMILE)surgery for myopia and myopic astigmatism in patients with thin corneas.METHODS:A prospective study included patients with thin corneas(preoperative thinnest corneal thickness ranging from 480 to 520μm)who underwent SMILE for myopia or myopic astigmatism.Corneal topography and posterior corneal elevation were assessed using Pentacam HR at three time points:preoperatively,1mo,and 6mo postoperatively.The measured parameters included thinnest point elevation(PTE),posterior maximal elevation(PME),posterior central elevation(PCE),and 24 additional reference points.RESULTS:A total of 106 eyes from 106 patients(age range:18-34)were included in the study.Uncorrected distance visual acuity(UDVA)improved significantly,with a mean logMAR value of-0.07±0.06 at the final follow-up visit.Measurements of posterior corneal elevation showed no significant changes in most points,hemispheres,and meridians at 6mo postoperatively.Notably,only two points,ΔE_(2mm-45°)andΔE_(2mm-90°),exhibited statistically significant elevation changes:the elevation ofΔE_(2mm-45°)increased from-2.3±4.99 to-1.0±5.9μm(P=0.0037),and that ofΔE_(2mm-90°)increased from-16±7.53 to-15±7.4μm(P=0.016).However,these changes were within the measurement error range of the Pentacam HR(±5μm in a 5 mm area).CONCLUSION:SMILE surgery is a safe and stable procedure for correcting myopia or myopic astigmatism in patients with thin corneas,as evidenced by the stability of posterior corneal elevation.展开更多
AIM:To assess early visual outcomes and corneal stability following small incision lenticule extraction(SMILE)in eyes with a pre-planned residual stromal thickness(RST)ranging from 280 to 300μm.METHODS:This retrospec...AIM:To assess early visual outcomes and corneal stability following small incision lenticule extraction(SMILE)in eyes with a pre-planned residual stromal thickness(RST)ranging from 280 to 300μm.METHODS:This retrospective study was designed to evaluate 82 eyes from 82 patients,all of whom had a pre-planned RST of 280 to 300μm and normal corneal topography prior to undergoing SMILE surgery.The mean preoperative spherical equivalent(SE)was-4.82±1.30 D.A standard follow-up protocol was conducted between 1 to 6mo postoperatively.Visual outcomes were recorded using uncorrected visual acuity(UCVA)and subjective refraction.The curvature of the anterior and posterior corneal surfaces,as well as the posterior elevation at the thinnest point(PTE)were derived from the Pentacam system.RESULTS:At the final follow-up,the efficacy index was 1.14±0.15,the safety index was 1.20±0.13.The mean preoperative UDVA was 0.78±0.16 logMAR,which improved significantly to-0.07±0.06 logMAR postoperatively(P<0.001).The preoperative mean SE was-4.82±1.30 D,which decreased to-0.14±0.30 D by the last visit.The curvature of the anterior cornea at the flat meridian(AK1)were 42.62±1.02 D preoperatively,38.56±1.37 D and 38.59±1.39 D at 1 and 6mo after operation,respectively.Corresponding measurements at the steep meridian(AK2)were 43.55±1.14 D preoperatively,39.18±1.46 D and 39.22±1.50 D at 1 and 6mo after operation,respectively.Both AK1 and AK2 remained stable at 1 and 6-mo postoperative intervals(P=0.126 and 0.082,respectively).There were no observed changes in the curvature of the posterior cornea at the flat meridian or at the steep meridian,or the PTE before and after surgery.CONCLUSION:SMILE represents a safe and effective procedure for the correction of myopia and astigmatism in eyes featuring a pre-planned RST ranging from 280 to 300μm accompanied by normal corneal topography,on the premise of strict control of surgical indications.展开更多
Background:Traditional imaging approaches to keratoconus(KCN)have thus far failed to produce a standardized approach for diagnosis.While many diagnostic modalities and metrics exist,none have proven robust enough to b...Background:Traditional imaging approaches to keratoconus(KCN)have thus far failed to produce a standardized approach for diagnosis.While many diagnostic modalities and metrics exist,none have proven robust enough to be considered a gold standard.This study aims to introduce novel metrics to differentiate between KCN and healthy corneas using three-dimensional(3D)measurements of surface area and volume.Methods:This retrospective observational study examined KCN patients along with healthy control patients between the ages of 20 and 79 years old at the University of Maryland,Baltimore.The selected patients underwent a nine-line raster scan anterior segment optical coherence tomography(AS-OCT).ImageJ was used to determine the central 6 mm of each image and each corneal image was then divided into six 1 mm segments.Free-D software was then used to render the nine different images into a 3D model to calculate corneal surface area and volume.A two-tailed Mann-Whitney test was used to assess statistical significance when comparing these subsets.Results:Thirty-three eyes with KCN,along with 33 healthy control,were enrolled.There were statistically significant differences between the healthy and KCN groups in the metric of anterior corneal surface area(13.927 vs.13.991 mm^(2),P=0.046),posterior corneal surface area(14.045 vs.14.173 mm^(2),P<0.001),and volume(8.430 vs.7.773 mm3,P<0.001)within the central 6 mm.Conclusions:3D corneal models derived from AS-OCT can be used to measure anterior corneal surface area,posterior corneal surface area,and corneal volume.All three parameters are statistically different between corneas with KCN and healthy corneas.Further study and application of these parameters may yield new methodologies for the detection of KCN.展开更多
[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and ...[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and a new method termed＆quot;opening a window on cornea and refixation＆quot; was used to prepare paraffin sections for cattle eyebal s in the treatment group. [Result] After the prepared specimens in the treatment group were fixed, it could be macroscopical y observed that retina and choroid were closely connected, with detachment occurring at a smal portion be-tween the two. According to the paraffin sections, it was microscopical y observed that the continuity of trabecular meshwork was intact, as wel as the continuity be-tween different layers of eyebal wal , without detachment between them, no retinal detachment, no shrinkage of each layer of tissue cells. [Conclusion] This study pro-vides a foundation for the basic research and pathological study of eyebal s.展开更多
Dipivefrin hydrochloride ophthalmic gel was prepared and the release test and the isolated cornea permeation test of the formulation in vitro were investigated. The release test of the formulation was studied by using...Dipivefrin hydrochloride ophthalmic gel was prepared and the release test and the isolated cornea permeation test of the formulation in vitro were investigated. The release test of the formulation was studied by using permeable membrane. The content and the release amount of Dipivefrin hydrochloride from the gel base were measured by high performance liquid chromatography. The cornea permeation test of the formulation was studied by using isolated rabbit corneas. The formulation release behavior in vitro followed the first-order kinetic equation. The release amount of Dipivefrin hydrochloride raised significantly with less polymer in the formulation. The cornea permeation behavior of the drug in vitro followed the first-order kinetic equation. The eye irritancy of Dipivefrin hydrochloride gel is lower than that of eyedrops.展开更多
AIM:To develop a new decellularization method depended upon the natural corneal structure and to harvest an ideal scaffold with good biocompatibilities for corneal reconstruction.METHODS:The acellular cornea matrix (A...AIM:To develop a new decellularization method depended upon the natural corneal structure and to harvest an ideal scaffold with good biocompatibilities for corneal reconstruction.METHODS:The acellular cornea matrix (ACM) were prepared from de-epithelium fresh porcine corneas (DFPCs) by incubation with 100% fresh human sera and additional electrophoresis at 4℃. Human corneal epithelial cells (HCEs) were used for the cytotoxicity tests of ACM. ACM were implanted into the Enhanced Green Fluorecence Protein (eGFP) transgenic mouse anterior chamber for evaluation of histocompatibility.RESULTS:HE and GSIB4 results showed fresh porcine cornea matrix with 100% human sera and electrophoresis could entirely decellularize stromal cell without reducing its transparency. ACM has no cytotoxic effect ex vivo. Animal test showed there was no rejection for one month after surgery.CONCLUSION:These results provide a decellularizing approach for the study of corneal tissue engineering and had the broader implications for the field of biological tissue engineering in other engineered organ or tissue matrix.展开更多
A large subset of corneal pathologies involves the formation of new vessels(neovascularization), leading to compromised visual acuity. This article aims to review the clinical causes and presentations of corneal neova...A large subset of corneal pathologies involves the formation of new vessels(neovascularization), leading to compromised visual acuity. This article aims to review the clinical causes and presentations of corneal neovascularization(CNV) by examining the mechanisms behind common CNV-related corneal pathologies, with a particular focus on herpes simplex stromal keratitis,contact lenses-induced keratitis and CNV secondary to keratoplasty. Moreover, we reviewed CNV in the context of different types of corneal transplantation and keratoprosthesis, and summarized the most relevant treatment available so far.展开更多
AIM:To reconstruct the lamellar cornea using human amniotic epithelial(HAE) cells and rabbit cornea stroma in vitro using tissue engineering technology.·METHODS:Human amnia taken from uncomplicated caesarean sect...AIM:To reconstruct the lamellar cornea using human amniotic epithelial(HAE) cells and rabbit cornea stroma in vitro using tissue engineering technology.·METHODS:Human amnia taken from uncomplicated caesarean sections were digested by collagenase to obtain HAE cells,and the cells were cultured to proliferate.Rabbit corneal epithelial cells were removed by n-heptanol to make lamellar matrix sheets.The second passage of HAE cells were cultured on the corneal stroma sheets for 1 or 2 days,then transferred to an air-liquid interface environment to culture for 2weeks.Tissue engineered lamellar cornea(TELC)morphology was observed by Hematoxylin-eosin(HE)staining;its ultrastructure was observed by transmission electron microscopy(TEM) and scanning electron microscopy(SEM);corneal epithelial cell-specific keratin3 and keratin 12 were detected with immunofluorescence microscopy.·RESULTS:HAE cells grew on the rabbit corneal stroma,forming a monolayer after 1-2 days.About 4-5 layers of epithelial cells developed after 2 weeks of air-liquid interface cultivation,a result similar to normal corneal epithelium.Rabbit corneal stromal cells were significantly reduced after one week,then almost completely disappeared after 2 weeks.TEM showed desmosomes between the epithelial cells;hemidesmosomes formed between the epithelial cells and the basement membrane.SEM revealed that the HAE cells which grew on the lamellar cornea had abundant microvilli.The tissue-engineered cornea expressed keratin 3 and keratin 12,as detected by immunofluorescence assay.·CONCLUSION:Functional tissue-engineered lamellar corneal grafts can be constructed in vitro using HAE cells and rabbit corneal stroma.展开更多
·AIM: To investigate whether decellularization using different techniques can reduce immunogenicity of the cornea, and to explore the decellularized cornea as a scaffold for cultured corneal endothelial cells(CEC...·AIM: To investigate whether decellularization using different techniques can reduce immunogenicity of the cornea, and to explore the decellularized cornea as a scaffold for cultured corneal endothelial cells(CECs).Transplantation of decellularized porcine corneas increases graft transparency and survival for longer periods compared with fresh grafts.·METHODS: Six-month-old wild-type pig corneas were cut into 100-200 μm thickness, and then decellularized by three different methods: 1) 0.1% sodium dodecyl sulfate(SDS); 2) hypoxic nitrogen(N2); and 3) hypertonic NaCl. Thickness and transparency were assessed visually. Fresh and decellularized corneas were stained with hematoxylin/eosin(H&E), and for the presence of galactose-α1,3-galactose(Gal) and N-glycolylneuraminic acid(NeuGc, a nonGal antigen). Also, a human IgM/IgG binding assay was performed. Cultured porcine CECs were seeded on the surface of the decellularized cornea and examined after H&E staining.· RESULTS: All three methods of decellularization reduced the number of keratocytes in the stromal tissue by 】80% while the collagen structure remained preserved. No remaining nuclei stained positive for Gal or NeuGc, and expression of these oligosaccharides on collagen was also greatly decreased compared to expression on fresh corneas. Human IgM/IgG binding to decellularized corneal tissue was considerably reduced compared to fresh corneal tissue. The cultured CECs formed a confluent monolayer on the surface of decellularized tissue.· CONCLUSION: Though incomplete, the significant reduction in the cellular component of the decellularized cornea should be associated with a significantly reduced in vivo immune response compared to fresh corneas.展开更多
基金Supported by National Natural Science Foundation of Guangdong,China(No.2020A1515010829,No.2023A1515011652,No.2025A1515012389)Science and Technology Program of Guangzhou,China(No.2025A03J4033).
文摘AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.
文摘Dry eye disease(DED)is a multifactorial disorder that disturbs ocular surface equilibrium,considerably diminishing quality of life.Present therapies only offer symptomatic alleviation.Stem cell treatment,especially mesenchymal stem cells(MSCs),has surfaced as a viable approach for tissue regeneration and immunological regulation in DED.Preclinical and early clinical investigations indicate that MSCs can improve lacrimal gland functionality,diminish inflammation,and facilitate corneal regeneration.Nonetheless,obstacles persist in enhancing MSC viability,determining the optimal MSC source,and guaranteeing sustained therapeutic effectiveness.Additional extensive randomized clinical trials are required to confirm the efficacy of MSC-based therapies for severe DED.
文摘Diabetic corneal neuropathy and diabetic retinopathy are ocular complications occurring in the context of diabetes mellitus.Diabetic corneal neuropathy refers to the progressive damage of corneal nerves.Diabetic retinopathy has traditionally been considered as damage to the retinal microvasculature.However,growing evidence suggests that diabetic retinopathy is a complex neurovascular disorder resulting from dysfunction of the neurovascular unit,which includes both the retinal vascular structures and neural tissues.Diabetic retinopathy is one of the leading causes of blindness and is frequently screened for as part of diabetic ocular screening.However,diabetic corneal neuropathy is commonly overlooked and underdiagnosed,leading to severe ocular surface impairment.Several studies have found that these two conditions tend to occur together,and they share similarities in their pathogenesis pathways,being triggered by a status of chronic hyperglycemia.This review aims to discuss the interconnection between diabetic corneal neuropathy and diabetic retinopathy,whether diabetic corneal neuropathy precedes diabetic retinopathy,as well as the relation between the stage of diabetic retinopathy and the severity of corneal neuropathy.We also endeavor to explore the relevance of a corneal screening in diabetic eyes and the possibility of using corneal nerve measurements to monitor the progression of diabetic retinopathy.
文摘The cornea is a transparent tissue that serves as the main refractive element of the eye ball.Limbal epithelial stem cells(LESCs),residing in the basal epithelial layer of the Palisades of Vogt located in the corneal limbus between cornea and scleral,are believed to be crucial for the continuous turnover of the corneal epithelium.The proliferation,migration,and differentiation of the LESCs are modulated by unique physical and chemical futures contained within the microenvironment known as the limbal niche.This niche,composed of nerve terminals,cells,extracellular matrix,vasculature,and signaling molecules,is the home for processes such as proliferation,migration and differentiation.Corneal nerve terminals possess special anatomical structures in the limbal region and basal epithelial cells,and they demonstrate pivotal biological effects in the regulation of the LESC function and corneal epithelium homeostasis.Biological molecules such as neuropeptides,neurotransmitters,and neurotrophic factors play a crucial role in modulating the LESCs phenotype responsible for corneal epithelium homeostasis.This paper will review recent studies on how these nerve derived molecules function in this process and provide clear orientations for future research.
文摘Background:Fluorescein is commonly used in ophthalmology for the assessment of ocular surface integrity.There have been limited studies on the effects of fluorescein on corneal endothelial cells.This study aims to assess the effect of the widely used fluorescein dye on human corneal endothelial cells(HCEnCs)in vitro at different concentrations and exposure times.Methods:B4G12,an immortalized human corneal endothelium cell line was cultured on pre-coated tissue culture flask with human endothelial-serum free medium(SFM)supplemented with 10 ng/mL basic fibroblast growth factor(bFGF).The fully confluent B4G12 cell monolayers in 96 well plates were treated with water as control,or fluorescein at various concentrations and exposure times.Cell viability was assessed using two techniques:Alamar Blue assay and cell morphology assessment with an inverted phase-contrast microscopy.Results:Short-term exposure to fluorescein(0.01-0.2%)for up to 30 minutes did not affect cell viability.Continuous fluorescein exposure however significantly reduced the viability of the cells with a notable reduction in cell metabolic activity with fluorescein treatments of 0.001%,0.01% and 0.05% for 1 day(and up to 4 days).Conclusions:Short-term exposure to fluorescein for up to 30 minutes in concentrations commonly used in clinical practice did not affect HCEnC viability.However,fluorescein exposure for longer durations can be detrimental to corneal endothelial cell health.Future studies should evaluate the effects of longer-term fluorescein exposure on endothelial function especially in susceptible patients including the elderly and patients with epithelial defects that enable diffusion of fluorescein towards the endothelium.
文摘AIM:To assess tomographic changes and subclinical edema detection in Fuchs’endothelial corneal dystrophy(FECD)through Scheimpflug tomography in a group of phakic patients contemplating cataract surgery.METHODS:A retrospective study was conducted on 30 phakic eyes from patients diagnosed with FECD but without clinical edema,and 59 phakic eyes from a control group without corneal alterations.Comprehensive ophthalmic examinations were conducted,including slitlamp biomicroscopy,corneal specular microscopy(CSM),and Scheimpflug tomography.RESULTS:The study encompassed 30 phakic eyes with FECD(mean age 59.8±13.1y)and 59 control eyes(mean age 61.3±7.7y).The best-corrected visual acuity was higher in the control group compared to the FECD group[0(0,0.08)vs 0.05(0,0.15)logMAR;P=0.042].CSM revealed significant differences between the FECD and control groups in several parameters:number of analyzed cells(26±13 vs 135±42,P<0.001),cell density(2049±376 vs 2479±225 cells/mm2,P<0.001),mean cell area[463(434,544)vs 397(383,431)μm2;P<0.001],coefficient of variation(54.8%±18.7%vs 41.0%±7.2%,P<0.001),and hexagonal cells[0(0,47%)vs 47%(40%,53%),P<0.001].Although often used as a clinical parameter for detecting edema,central corneal thickness measured by CSM showed no significant difference between the FECD and control groups(530±57 vs 546±30μm,P=0.179).Significant differences were noted in various Pentacam measurements between the groups.Specifically,parameters like loss of parallel isopachs(13 vs 0 eyes,P<0.001),displacement of the thinnest point(11 vs 0 eyes,P<0.001),posterior focal depression(25 vs 7 eyes,P<0.001),and increased light scatter[21.4(17.6;23.9)vs 18.0(16.8,21.8),P=0.01]were significantly more prevalent in FECD eyes,reflecting the presence of subclinical edema and loss of corneal transparency.CONCLUSION:Scheimpflug tomography allows for an objective assessment of FECD,offering the capability to detect subclinical edema at an early stage,monitor disease progression,and serve as a predictor of corneal decompensation following cataract surgery.
文摘AIM:To investigate the changes in posterior corneal elevation within 6mo after small incision lenticule extraction(SMILE)surgery for myopia and myopic astigmatism in patients with thin corneas.METHODS:A prospective study included patients with thin corneas(preoperative thinnest corneal thickness ranging from 480 to 520μm)who underwent SMILE for myopia or myopic astigmatism.Corneal topography and posterior corneal elevation were assessed using Pentacam HR at three time points:preoperatively,1mo,and 6mo postoperatively.The measured parameters included thinnest point elevation(PTE),posterior maximal elevation(PME),posterior central elevation(PCE),and 24 additional reference points.RESULTS:A total of 106 eyes from 106 patients(age range:18-34)were included in the study.Uncorrected distance visual acuity(UDVA)improved significantly,with a mean logMAR value of-0.07±0.06 at the final follow-up visit.Measurements of posterior corneal elevation showed no significant changes in most points,hemispheres,and meridians at 6mo postoperatively.Notably,only two points,ΔE_(2mm-45°)andΔE_(2mm-90°),exhibited statistically significant elevation changes:the elevation ofΔE_(2mm-45°)increased from-2.3±4.99 to-1.0±5.9μm(P=0.0037),and that ofΔE_(2mm-90°)increased from-16±7.53 to-15±7.4μm(P=0.016).However,these changes were within the measurement error range of the Pentacam HR(±5μm in a 5 mm area).CONCLUSION:SMILE surgery is a safe and stable procedure for correcting myopia or myopic astigmatism in patients with thin corneas,as evidenced by the stability of posterior corneal elevation.
文摘AIM:To assess early visual outcomes and corneal stability following small incision lenticule extraction(SMILE)in eyes with a pre-planned residual stromal thickness(RST)ranging from 280 to 300μm.METHODS:This retrospective study was designed to evaluate 82 eyes from 82 patients,all of whom had a pre-planned RST of 280 to 300μm and normal corneal topography prior to undergoing SMILE surgery.The mean preoperative spherical equivalent(SE)was-4.82±1.30 D.A standard follow-up protocol was conducted between 1 to 6mo postoperatively.Visual outcomes were recorded using uncorrected visual acuity(UCVA)and subjective refraction.The curvature of the anterior and posterior corneal surfaces,as well as the posterior elevation at the thinnest point(PTE)were derived from the Pentacam system.RESULTS:At the final follow-up,the efficacy index was 1.14±0.15,the safety index was 1.20±0.13.The mean preoperative UDVA was 0.78±0.16 logMAR,which improved significantly to-0.07±0.06 logMAR postoperatively(P<0.001).The preoperative mean SE was-4.82±1.30 D,which decreased to-0.14±0.30 D by the last visit.The curvature of the anterior cornea at the flat meridian(AK1)were 42.62±1.02 D preoperatively,38.56±1.37 D and 38.59±1.39 D at 1 and 6mo after operation,respectively.Corresponding measurements at the steep meridian(AK2)were 43.55±1.14 D preoperatively,39.18±1.46 D and 39.22±1.50 D at 1 and 6mo after operation,respectively.Both AK1 and AK2 remained stable at 1 and 6-mo postoperative intervals(P=0.126 and 0.082,respectively).There were no observed changes in the curvature of the posterior cornea at the flat meridian or at the steep meridian,or the PTE before and after surgery.CONCLUSION:SMILE represents a safe and effective procedure for the correction of myopia and astigmatism in eyes featuring a pre-planned RST ranging from 280 to 300μm accompanied by normal corneal topography,on the premise of strict control of surgical indications.
文摘Background:Traditional imaging approaches to keratoconus(KCN)have thus far failed to produce a standardized approach for diagnosis.While many diagnostic modalities and metrics exist,none have proven robust enough to be considered a gold standard.This study aims to introduce novel metrics to differentiate between KCN and healthy corneas using three-dimensional(3D)measurements of surface area and volume.Methods:This retrospective observational study examined KCN patients along with healthy control patients between the ages of 20 and 79 years old at the University of Maryland,Baltimore.The selected patients underwent a nine-line raster scan anterior segment optical coherence tomography(AS-OCT).ImageJ was used to determine the central 6 mm of each image and each corneal image was then divided into six 1 mm segments.Free-D software was then used to render the nine different images into a 3D model to calculate corneal surface area and volume.A two-tailed Mann-Whitney test was used to assess statistical significance when comparing these subsets.Results:Thirty-three eyes with KCN,along with 33 healthy control,were enrolled.There were statistically significant differences between the healthy and KCN groups in the metric of anterior corneal surface area(13.927 vs.13.991 mm^(2),P=0.046),posterior corneal surface area(14.045 vs.14.173 mm^(2),P<0.001),and volume(8.430 vs.7.773 mm3,P<0.001)within the central 6 mm.Conclusions:3D corneal models derived from AS-OCT can be used to measure anterior corneal surface area,posterior corneal surface area,and corneal volume.All three parameters are statistically different between corneas with KCN and healthy corneas.Further study and application of these parameters may yield new methodologies for the detection of KCN.
基金Supported by China Agriculture Research System(CARS-38)~~
文摘[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and a new method termed＆quot;opening a window on cornea and refixation＆quot; was used to prepare paraffin sections for cattle eyebal s in the treatment group. [Result] After the prepared specimens in the treatment group were fixed, it could be macroscopical y observed that retina and choroid were closely connected, with detachment occurring at a smal portion be-tween the two. According to the paraffin sections, it was microscopical y observed that the continuity of trabecular meshwork was intact, as wel as the continuity be-tween different layers of eyebal wal , without detachment between them, no retinal detachment, no shrinkage of each layer of tissue cells. [Conclusion] This study pro-vides a foundation for the basic research and pathological study of eyebal s.
文摘Dipivefrin hydrochloride ophthalmic gel was prepared and the release test and the isolated cornea permeation test of the formulation in vitro were investigated. The release test of the formulation was studied by using permeable membrane. The content and the release amount of Dipivefrin hydrochloride from the gel base were measured by high performance liquid chromatography. The cornea permeation test of the formulation was studied by using isolated rabbit corneas. The formulation release behavior in vitro followed the first-order kinetic equation. The release amount of Dipivefrin hydrochloride raised significantly with less polymer in the formulation. The cornea permeation behavior of the drug in vitro followed the first-order kinetic equation. The eye irritancy of Dipivefrin hydrochloride gel is lower than that of eyedrops.
基金National Natural Science Foundation of China (No.81160118,81100648,81101858,81100649)Natural Science Foundation of Jiangxi Province,China (No.20114BAB215029)+3 种基金Technology Foundation of Jiangxi Province,China (No.20111BBG70026-2)Health Department Science and Technology Foundation,China (No.20121026)Education Department Youth Scientific Research Foundation,China (No.JJJ12158)National High Technology Research of China (863 project)(No.2006AA02A131)
文摘AIM:To develop a new decellularization method depended upon the natural corneal structure and to harvest an ideal scaffold with good biocompatibilities for corneal reconstruction.METHODS:The acellular cornea matrix (ACM) were prepared from de-epithelium fresh porcine corneas (DFPCs) by incubation with 100% fresh human sera and additional electrophoresis at 4℃. Human corneal epithelial cells (HCEs) were used for the cytotoxicity tests of ACM. ACM were implanted into the Enhanced Green Fluorecence Protein (eGFP) transgenic mouse anterior chamber for evaluation of histocompatibility.RESULTS:HE and GSIB4 results showed fresh porcine cornea matrix with 100% human sera and electrophoresis could entirely decellularize stromal cell without reducing its transparency. ACM has no cytotoxic effect ex vivo. Animal test showed there was no rejection for one month after surgery.CONCLUSION:These results provide a decellularizing approach for the study of corneal tissue engineering and had the broader implications for the field of biological tissue engineering in other engineered organ or tissue matrix.
文摘A large subset of corneal pathologies involves the formation of new vessels(neovascularization), leading to compromised visual acuity. This article aims to review the clinical causes and presentations of corneal neovascularization(CNV) by examining the mechanisms behind common CNV-related corneal pathologies, with a particular focus on herpes simplex stromal keratitis,contact lenses-induced keratitis and CNV secondary to keratoplasty. Moreover, we reviewed CNV in the context of different types of corneal transplantation and keratoprosthesis, and summarized the most relevant treatment available so far.
基金National Natural Science Foundation of China (No.30872808No.81100637)
文摘AIM:To reconstruct the lamellar cornea using human amniotic epithelial(HAE) cells and rabbit cornea stroma in vitro using tissue engineering technology.·METHODS:Human amnia taken from uncomplicated caesarean sections were digested by collagenase to obtain HAE cells,and the cells were cultured to proliferate.Rabbit corneal epithelial cells were removed by n-heptanol to make lamellar matrix sheets.The second passage of HAE cells were cultured on the corneal stroma sheets for 1 or 2 days,then transferred to an air-liquid interface environment to culture for 2weeks.Tissue engineered lamellar cornea(TELC)morphology was observed by Hematoxylin-eosin(HE)staining;its ultrastructure was observed by transmission electron microscopy(TEM) and scanning electron microscopy(SEM);corneal epithelial cell-specific keratin3 and keratin 12 were detected with immunofluorescence microscopy.·RESULTS:HAE cells grew on the rabbit corneal stroma,forming a monolayer after 1-2 days.About 4-5 layers of epithelial cells developed after 2 weeks of air-liquid interface cultivation,a result similar to normal corneal epithelium.Rabbit corneal stromal cells were significantly reduced after one week,then almost completely disappeared after 2 weeks.TEM showed desmosomes between the epithelial cells;hemidesmosomes formed between the epithelial cells and the basement membrane.SEM revealed that the HAE cells which grew on the lamellar cornea had abundant microvilli.The tissue-engineered cornea expressed keratin 3 and keratin 12,as detected by immunofluorescence assay.·CONCLUSION:Functional tissue-engineered lamellar corneal grafts can be constructed in vitro using HAE cells and rabbit corneal stroma.
基金Supported in part by NIH Grants#1RO3A 1096296-01 (HH), #IU19A1090959-01 (DKCC), #U01A 1066331 (DKCC), and #5P01 HL107152-02 (DKCC)Ocular Tissue Engineering and Regenerative Ophthalmology (OTERO) Postdoctoral Fellowship (WL)Sponsored Research Agreements Between the University of Pittsburgh and Revivicor, Blacksburg, VA
文摘·AIM: To investigate whether decellularization using different techniques can reduce immunogenicity of the cornea, and to explore the decellularized cornea as a scaffold for cultured corneal endothelial cells(CECs).Transplantation of decellularized porcine corneas increases graft transparency and survival for longer periods compared with fresh grafts.·METHODS: Six-month-old wild-type pig corneas were cut into 100-200 μm thickness, and then decellularized by three different methods: 1) 0.1% sodium dodecyl sulfate(SDS); 2) hypoxic nitrogen(N2); and 3) hypertonic NaCl. Thickness and transparency were assessed visually. Fresh and decellularized corneas were stained with hematoxylin/eosin(H&E), and for the presence of galactose-α1,3-galactose(Gal) and N-glycolylneuraminic acid(NeuGc, a nonGal antigen). Also, a human IgM/IgG binding assay was performed. Cultured porcine CECs were seeded on the surface of the decellularized cornea and examined after H&E staining.· RESULTS: All three methods of decellularization reduced the number of keratocytes in the stromal tissue by 】80% while the collagen structure remained preserved. No remaining nuclei stained positive for Gal or NeuGc, and expression of these oligosaccharides on collagen was also greatly decreased compared to expression on fresh corneas. Human IgM/IgG binding to decellularized corneal tissue was considerably reduced compared to fresh corneal tissue. The cultured CECs formed a confluent monolayer on the surface of decellularized tissue.· CONCLUSION: Though incomplete, the significant reduction in the cellular component of the decellularized cornea should be associated with a significantly reduced in vivo immune response compared to fresh corneas.
