Clinical associations of corneal neuromas with ocular surface diseases

Corneal neuromas,also termed microneuromas,refer to microscopic,irregula rly-shaped enlargements of terminal subbasal nerve endings at sites of nerve damage or injury.The formation of corneal neuromas results from damage to corneal nerves,such as following corneal pathology or corneal or intraocular surge ries.Initially,denervated areas of sensory nerve fibers become invaded by sprouts of intact sensory nerve fibers,and later injured axons regenerate and new sprouts called neuromas develop.In recent years,analysis of corneal nerve abnormalities including corneal neuromas which can be identified using in vivo confocal microscopy,a non-invasive imaging technique with microscopic resolution,has been used to evaluate corneal neuropathy and ocular surface dysfunction.Corneal neuromas have been shown to be associated with clinical symptoms of discomfort and dryness of eyes,and are a promising surrogate biomarker for ocular surface diseases,such as neuropathic corneal pain,dry eye disease,diabetic corneal neuropathy,neurotrophic keratopathy,Sjogren's syndrome,bullous keratopathy,post-refra ctive surgery,and others.In this review,we have summarized the current literature on the association between these ocular surface diseases and the presentation of corneal microneuromas,as well as elaborated on their pathogenesis,visualization via in vivo confocal microscopy,and utility in monitoring treatment efficacy.As current quantitative analysis on neuromas mainly relies on manual annotation and quantification,which is user-dependent and labor-intensive,future direction includes the development of artificial intelligence software to identify and quantify these potential imaging biomarkers in a more automated and sensitive manner,allowing it to be applied in clinical settings more efficiently.Combining imaging and molecular biomarkers may also help elucidate the associations between corneal neuromas and ocular surface diseases.

Knockout of TMEM206 in mice associated with a loss of corneal transparency

AIM:To investigate the role of transmembrane protein 206(TMEM206)in corneal edema in mice by knockout the TMEM206 gene using CRISPR/Cas9 editing technology.METHODS:TMEM206-knockout mice were generated using the CRISPR-Cas9 system.Variations in ophthalmic pathology were observed using slit lamp microscope and optical coherence tomography(OCT),intraocular pressure(IOP)was measured using a TonoLab Rebound Tonometer,and the ultrastructure of the corneal was observed using a transmission electron microscope.RESULTS:Corneal opacity was observed in 4/18 homozygous TMEM206^(-/-)mice whereas a similar change was not observed in heterozygous TMEM206^(+/-)mice and wild-type littermates.OCT examination showed that the mean central cornea thickness was 125±5.4μm in 4 homozygous TMEM206^(-/-)mice developed corneal edema and 115±1.2μm in wild-type mice(t=3.468,P<0.05)at 43wk.The mean IOP was 12.08±0.07 mm Hg in four right eyes with corneal edema and 12.03±0.03 mm Hg in three normal left eyes(P>0.05).Transmission electron microscopy revealed a disruption in the organization of the collagen fibrils in the central part of the cornea in homozygous TMEM206^(-/-)mice.CONCLUSION:TMEM206 is associated with corneal edema which caused organizational disruption of collagen fibrils in corneas of mice.

Interconnections between diabetic corneal neuropathy and diabetic retinopathy:diagnostic and therapeutic implications

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.

Double intrastromal corneal ring segment implantation: a new approach for improved clinical outcomes in keratoconus patients

AIM:To evaluate the clinical outcomes after subsequent implantation of a new intrastromal corneal ring segment(ICRS)model followed by an additional short-arc ICRS implant in keratoconus patients.METHODS:This retrospective single-arm cohort study evaluated 25 eyes of 21 keratoconus patients implanted with the new ICRS followed by 140-arch length ICRS(140-ICRS)implantation.Uncorrected distance visual acuity(UDVA,logMAR),corrected distance visual acuity(CDVA,logMAR),sphere,astigmatism,keratometry,spherical equivalent(SE),and asphericity were compared preoperatively and postoperatively after both ICRS implantation.RESULTS:The average follow-up time after 140-ICRS implantation was 6.40±2.20mo.The mean preoperative UDVA improved from 1.27±0.14 preoperative to 0.52±0.26 after both ICRS implantation(P=0.03).The mean sphere value reduced from-5.34±2.74 preoperatively to-2.06±1.84 postoperatively(P<0.001)after the first ICRS implantation and decreased to-0.59±1.54 postoperatively(P<0.001)after 140-ICRS implantation.The mean preoperative astigmatism was-3.72±1.56 and improved to-2.82±1.08 after the first ICRS implantation,and following the 140-ICRS implantation,the mean astigmatism was-1.37±0.67(P=0.001).The SE and asphericity changes were statistically significant(P<0.001).The researchers did not find intraoperative or postoperative complications for both procedures.CONCLUSION:The combination of 2 different ICRSs can efficiently regularize the cornea,reduce the SE,and improve visual acuity in selected keratoconus patients.

The Limbal Niche and Its Role in Maintaining Corneal Regeneration

In recent years, stem cells have been a focal point in research designed to evaluate the efficacy of ophthalmologic therapies, specifically those for corneal conditions. The corneal epithelium is one of the few regions of the body that maintains itself using a residual stem cell population within the adjacent limbus. Stem cell movement has additionally captivated the minds of researchers due to its potential application in different body regions. The cornea is a viable model for varying methods to track stem cell migratory patterns, such as lineage tracing and live imaging from the limbus. These developments have the potential to pave the way for future therapies designed to ensure the continuous regeneration of the corneal epithelium following injury via the limbal stem cell niche. This literature review aims to analyze the various methods of imaging used to understand the limbal stem cell niche and possible future directions that might be useful to consider for the better treatment and prevention of disorders of the cornea and corneal epithelium. .

Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.

Thiel-Behnke Corneal Dystrophy in a Young Man in Denmark—A Case Report

Background: This case report presents a case of bilateral Thiel-Behnke corneal dystrophy in Denmark. Thiel-Behnke is an autosomal dominant inherited epithelial-stromal TGFBI dystrophy causing visual impairment. Methods and Results: This case study presents a 24-year-old Lithuanian man, with no previous ocular history, who had experienced slowly progressive visual impairment since his childhood. He was examined at the Department of Ophthalmology at Vejle Hospital and Aarhus University Hospital, where he was diagnosed with bilateral Thiel-Behnke corneal dystrophy. Histology confirmed the diagnosis. A lamellar corneal transplantation was performed in the right eye;however, due to epithelial growth under the corneal graft, it was later decided to redo the operation. Following the operations, the patient experienced a visual improvement in best corrected visual acuity (BCVA) from 0.1 (20/25 Snellen equivalent) to 0.3 (20/40 Snellen equivalent) in his right eye. Conclusions: This case of Thiel-Behnke corneal dystrophy is to our knowledge the first reported case in Denmark.

Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

AIM： To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty.·METHODS： The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups,Group A（16 eyes） with femtosecond laser-assisted deep lamellar keratoplasty 24 h after burn and Group B（16 eyes）without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy（TEM） at 1, 2, 3,and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology.· RESULTS： The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached.· CONCLUSION： Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

COMPARATIVE STUDIES ON THE CORNEAL STRUCTURE OF MAMMAL ANIMALS:I.ULTRASTRUCTURE OF THE CORNEAL SUBSTANTIA PROPRIA IN GUINEA PIG

The corneal sutotantia propria in guinea pig is composed of the fibroblasts,fibers andintercelular maxtrix.Tab fibers belong to collagen fibrils.The fibrils are fine(about 37nm in diameter)and form lamelae being parallel to one another.The lamelae are approximately 0.75￣1.5μmthick. The fibrils in adjacent lamelae run across each other at right angles and parallel to the cornealsurface.in fibroblasts are dispersed between the fibril lamelae. Their appearances are extremelyflat. The nucleus is large and located at the canter of the cell.The cytoplasm is abundant in roughendoplasmic reticulum.The corned fibroblasts give out very long processes extended between thelamelae.The cytoplasmic brocades of a cell are in able contant with these of neighboring cells.Thecontant surfaces show irregular and interdigital forms. In some of the intercellular contant regionsthere are gap junctions.

Research progress on animal models of corneal epithelial-stromal injury

A corneal epithelial-stromal defect is recognized as a major contributor to corneal scarring.Given the rising prevalence of blindness caused by corneal scarring,increasing attention has been focused on corneal epithelialstromal defects.Currently,the etiology and pathogenesis of these defects remain inadequately understood,necessitating further investigation through experimental research.Various modeling methods exist both domestically and internationally,each with distinct adaptive conditions,advantages,and disadvantages.This review primarily aims to summarize the techniques used to establish optimal animal models of corneal epithelial-stromal injury,including mechanical modeling,chemical alkali burns,post-refractive surgery infections,and genetic engineering.The intention is to provide valuable insights for studying the mechanisms underlying corneal epithelial-stromal injury and the development of corresponding therapeutic interventions.

A HISTOPATHOLOGIC IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL STUDY OF RABBIT CORNEA AFTER EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY

Objective To evaluate the corneal healing of non-epuality diopter response histopathologically, immunohistochemically and ultrastructurally after excimer laser photorefractive keratectomy(PRK) with SVS APEX PLUS(Summit Technology Inc. USA) excimer laser, and the effects of corticosteroid on the healing. Methods PRK on 6 white rabbits(12 eyes) was performed on right eye or the rabbit for an attampted correction or -4.00 diopter and on left eye for an attempted correction of -8.00 diopter. The rabbits were divided into 2 groups randomly and each group included 6 eyes: Group FLM (3 rabbits, 6 eyes) and group CM (3 rabbits, 6 eyes). Fluoromethalone was given to group FLM,and chloromycetin to group CM. On 10d, 30d and 100d,the eyes of one rabbit in each group were enucleated randomly. Half of each cornea was prepared for electron microscope observation (SEM and TEM) and the rest embedded in OCT compound for immunohistochemical study to examine Ⅲ-C and FN. Results All eyes were reepithelialized within 3d after PRK. Subepithelial corneal haze was observed on 15d,which was dominant on 30 or 60d. On 100d postoperatively,corneal hazes of 11 eyes were grades 0 or 0.5,only 1 eye(the left eye or group CM) was denser haze (grade 1). On 3d postoperatively, one or two layers of corneal epithelial cell covered the ablation zone. On 30d after PRK,the epithelial cells showed hyperplastic changes. The cells were larger and increased from normal 5 or 6 layers to 7 or 8 layers of cells on l00d after PRK,epithelium was clear with more bright epithelium. Mi- croplicae and microvilli were less than before. The expression of Ⅲ-C and FN in group CM was significantly more evi- dent than that in group FLM. Conclusion The study show that despite recovery of a continuous and smooth epithelial layer and nearly normal corneal tissues on 100d after PRK,abnormalities of both epithelium and superficial stroma can be detected in the area of ablation. The ablation depth of stroma can influence the appearance of corneal haze af- ter PRK. The microplicae and microvilli of rabbit cornea epithelium become less after PRK,which can be one of cause leading to ocular dry sensation in some patients.

Single-cell RNA sequencing in cornea research:Insights into limbal stem cells and their niche regulation

The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye,which acts as a protective barrier and is critical for clear and stable vision.Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells(LSCs),a cell population that resides at the limbus in a highly regulated niche.Dysfunction of LSCs or their niche can cause limbal stem cell deficiency,a disease that is manifested by failed epithelial wound healing or even blindness.Nevertheless,compared to stem cells in other tissues,little is known about the LSCs and their niche.With the advent of single-cell RNA sequencing,our understanding of LSC characteristics and their microenvironment has grown considerably.In this review,we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology,including the heterogeneity of the LSC population,novel LSC markers and regulation of the LSC niche,which will provide a reference for clinical issues such as corneal epithelial wound healing,ocular surface reconstruction and interventions for related diseases.

Corneal Blindness Caused by Accidental Ocular Use of Chlorhexidine (Hexz) Gel in Two Newborn Born in the Health District of Kati in Mali

Introduction: Corneal opacities in children are relatively common. In children, it is urgent because of the risk of irreversible amblyopia. The causes of these blindnesses vary considerably according to the regions of the world. Chlorhexidine digluconate is a broad-spectrum antiseptic directed against gram-positive and gram-negative bacteria. It has been used as an antiseptic for more than 50 years, both in humans and in animals. However, despite these benefits, it can cause serious damage if applied to the eyes. Incidents of eye damage with 7.1% chlorhexidine have been reported to WHO across Africa. Observation: We report and write two cases of bilateral corneal blindness caused by accidental ocular use of chlorhexidine (HEXZ) GEL 7.1% in two newborns in the health district of Kati in MALI. The ophthalmological examination had revealed corneal opacity, conjunctival hyperaemia and limbic ischemia greater than 50% in 1 eye out of 4, corresponding to stage IV of the ROPPER HALL classification;2 eyes out of 4 were at stage III and 1 eye out of 4 was at stage I of the same classification. Conclusion: It is essential to ensure correct use of chlorhexidine digluconate gel 7%. It is an antiseptic which should not be used on the ocular and auditory mucous membranes, at the risk of most often permanent burns.

The Mean Central Cornea Thickness and Associated Factors among Adult Patients Attending Mulago Hospital Eye Clinic Kampala, Uganda

Background: The mean central corneal thickness (CCT) values are known to have an influence on intraocular pressure measurement and vary widely with age, sex and ethnicity. Little is known about the pattern of CCT in central Uganda. Aim: To determine the mean central corneal thickness and its associated factors among adult patients attending Mulago Hospital eye clinic, Kampala Uganda. Design and Method: A cross sectional study was done from August to October 2016 on 270 adult patients selected by systemic random sampling. The study included all adult patients who attended the eye clinic during the study period and consented to the study excluding those who had conditions causing abnormal thinning, thickening or irregularity of the cornea. The participants were evaluated by history taking and ocular examination including visual acuity assessment, slit lamp examination, central cornea thickness measurement, intraocular pressure measurement and funduscopy. Data were collected using a pretested questionnaire, entered using Epidata and analyzed by STATA11.0. Results: Of the 270 patients examined, 61% were female, 39% male, the mean age being 42 years ranging from 18 to 96 years. The mean central corneal thickness for both eyes was 539.3 (SD ± 41.65 μm) ranging from 332 μm to 701 μm and mean intraocular pressure was 15 (SD ± 5.34) mmHg. Gender, ethnicity, IOP, glaucoma, hypertension, diabetes, refractive error, were not statistically significantly associated with central cornea thickness. However central cornea thickness was statistically significantly associated with systolic blood pressure (r = -0.24, p = 0.025) and age (p = 0.002). A one-year increase in age reduced the mean central cornea thickness by 0.54 μm. Conclusion: The average CCT of Ugandan adult population was 539.3 ± 41.65 μm which falls in the category of normal central cornea thickness. Central corneal thickness reduced with increasing age and increasing systolic blood pressure.

Central Corneal Thickness of Diabetic Patients in Yaoundé: Case Control Study

Background: To compare central corneal thickness (CCT) values measured in diabetic eyes and compare the CCT values in normal patients without diabetes. Methods: A total of 83 diabetic patients and 83 non-diabetic patients were prospectively enrolled in this comparative case series. CCT was measured using a Topcon CT-1P non-contact automated pachymeter, and values were compared. Results: Mean age was 57 ± 11 years, with a range of 23 and 80 years. The mean CCT was 508.87 ± 35.83 μm for diabetic patients and 513.41 ± 37.22 μm for non-diabetic patients. There was no statistically significant difference between the CCT of diabetic patients compared to non-diabetic patients (p = 0.260). We did not find a significant correlation between the CCT of diabetic patients and clinical characteristics of diabetes. However, there was a positive and statistically significant linear correlation between the CCT of diabetic patients and intra ocular pressure (IOP). Conclusion: The mean CCT in diabetic patients was lower than in non-diabetic control patients, although there was no statistically significant difference.

Corneal neurotization: a narrative review of techniques, outcomes, and surgical considerations

Background and Objective:Corneal neurotization is a novel surgical technique used to restore corneal sensation in patients with neurotrophic keratopathy.Neurotrophic keratopathy is a disorder characterized by dysfunction of the ophthalmic division of the trigeminal nerve,which provides sensory innervation to the cornea.Without sensation,the cornea is at risk of infection,ulceration,perforation,and ultimately,vision loss.Corneal neurotization has emerged as an innovative technique to reinnervate anesthetized corneas by transferring a healthy donor nerve to the affected eye around the corneoscleral limbus.As the field of corneal neurotization rapidly grows,there is a need to synthesize the existing body of literature on corneal neurotization and identify important areas for further research.In this review,we will discuss neurotrophic keratopathy and its current management strategies,followed by an overview of corneal neurotization techniques,outcomes,surgical considerations,and future directions.Methods:PubMed and Google Scholar searches were conducted to retrieve and analyze relevant original papers and reviews on neurotrophic keratopathy and corneal neurotization up until April 2022.Key Content and Findings:Currently,numerous techniques for corneal neurotization exist,including direct nerve transfers,as well as indirect neurotization via interposition nerve grafts.So far,corneal neurotization has been shown to be highly successful in restoring corneal sensation,improving visual acuity,and improving corneal epithelial health.To date,there have been no significant differences in outcomes between direct versus indirect neurotization techniques,different donor nerves,or autologous versus allogeneic interposition grafts.However,there is some evidence that corneal neurotization procedures may be more successful in pediatric patients.Conclusions:Corneal neurotization shows great promise in treating neurotrophic corneas and represents the first management option to date that addresses the underlying pathophysiological mechanism of neurotrophic keratopathy by restoring corneal sensation.As the use of corneal neurotization continues to broaden,additional studies will become important to compare techniques in a systematic manner,with larger sample sizes,as well as standardized outcome measures and follow-up time.

角巩膜缘与角膜切口超声乳化术治疗老年白内障疗效对比

目的 对比角巩膜缘与角膜切口超声乳化术治疗老年白内障的临床疗效。方法 随机将80例老年白内障患者分为2组。2组均行超声乳化术,对照组采用角膜切口,观察组采用角巩膜缘切口。比较2组上皮修复时间、切口修复时间、裸眼视力、最佳矫正视力(BCVA)、角膜散光度、手术源性角膜散光度、泪囊破裂时间(BUT)、角膜荧光素染色评分(FLCs)、泪液分泌试验(SIt)水平以及术后并发症发生率。结果 观察组上皮修复、切口修复时间均早于对照组(P<0.05);观察组术后1周、2周、4周时裸眼视力、BCVA水平以及BUT、Sit水平均高于对照组(P<0.05);观察组术后1周、2周、4周时角膜散光度、手术源性角膜散光度以及FLCs水平水平均低于对照组(P<0.05);2组术后并发症发生率(18%与12%)差异无统计学意义(P>0.05)。结论 角巩膜缘切口超声乳化术治疗老年白内障临床疗效较好,患者术后角膜散光度较低,且视力、泪膜功能稳定性恢复较好。

生物工程角膜板层角膜移植在真菌性角膜溃疡患者中的应用

目的探讨生物工程角膜板层角膜移植在真菌性角膜溃疡患者中的有效性及安全性。方法选取44例真菌性角膜溃疡患者为研究对象,根据使用的角膜材料分为生物工程组[采用脱细胞猪角膜基质(APCM)进行板层角膜移植,20例]和人供体组(采用人供体角膜材料进行板层角膜移植,24例)。比较两组术后不同时间角膜植片透明度评分、最佳矫正视力(BCVA)和术后角膜上皮愈合时间、术后并发症及复发率。结果术后1、3、6、12个月,随着时间的延长两组角膜植片透明度评分均逐渐降低,术后1、3、6个月生物工程组角膜植片透明度评分高于人供体组(P<0.05),但术后12个月两组角膜植片透明度评分比较,差异无统计学意义(P>0.05)。术后3、6、12个月,随着时间的延长两组患眼BCVA均逐渐增加,但生物工程组患眼术后3、6、12个月的BCVA均低于人供体组(P<0.05);两组角膜上皮愈合时间及术后角膜上皮愈合延迟、角膜植片排斥、角膜植片溶解、新生血管长入角膜植片4项并发症发生率和术后复发率比较,差异无统计学意义(P>0.05)。结论以APCM为材料进行板层角膜移植治疗真菌性角膜溃疡临床效果好,安全性高,可作为生物工程角膜应用于角膜病致盲的治疗。

天然高分子基角膜修复材料力学性能研究进展

由于盲人数量庞大、可供移植的捐赠角膜供不应求,人工角膜逐渐成为研究热点,但人工角膜常因力学性能不足而发生植片撕裂,为克服这一问题,国内外研究者开展了一系列研究工作尝试改善人工角膜的力学性能。文章针对胶原蛋白、明胶、丝素蛋白以及壳聚糖这4类常见的天然高分子基角膜修复材料的力学性能相关进展进行了总结。结果发现,通过光交联、热交联等物理方法,1-乙基-3-(3-二甲基氨基丙基)碳二亚胺(EDC)/N-羟基琥珀酰亚胺(NHS)交联、京尼平或戊二醛交联等化学方法以及其他复合方法都可以显著提升角膜材料的力学性能,但这些方法仍存在一些不足之处。因此,进一步开发高质量人工角膜至关重要,文章通过归纳总结希望能够为角膜修复材料的力学性能提升研究提供一些参考和思路。

角膜塑形镜矫正效果影响因素的数值模拟

【目的】角膜形态以及角膜和塑形镜材料的力学性能对塑形镜矫正效果存在一定的影响。【方法】使用超弹性本构建立角膜配戴塑形镜的有限元模型,通过改变角膜的形态(不同曲率和厚度)以及角膜和塑形镜的材料参数,分析戴镜后角膜的生物力学响应。【结果】结果表明:角膜曲率变化4 m-1时,角膜中央区顶点处位移差值变化了15.7μm;角膜厚度变化75μm时,中央区顶点处位移差值变化了12.3μm;角膜材料参数k1值变化3倍时,角膜中央区顶点处位移差值的变化量为39.2μm,C10值变化4倍时位移差值的变化量为55.5μm,而塑形镜材料参数E值变化3倍时,位移差值的变化量仅为0.2μm.【结论】临床上采用角膜塑形镜矫正近视时,需要充分考虑角膜形态和角膜本身的力学性能对矫正效果的影响。