Corneal Changes Research Articles

Corneal Refractive Surgery Considerations in Patients With History of Orthokeratology

Objective: To review the current literature describing corneal changes observed with orthokeratology (ortho-k) use and to formulate preliminary recommendations for these patients seeking corneal refractive surgery. Methods: The literature search was conducted through the PubMed, Scopus, and Ovid databases through June 4, 2024, for articles regarding corneal physiological, tomographic, and biomechanical changes secondary to ortho-k use. Results: Forty-one articles were found describing several changes associated with ortho-k use, including higher corneal staining, central corneal epithelial thinning and midperipheral thickening, increased higher-order aberrations, decreased contrast sensitivity, reduced corneal hysteresis and corneal resistance factor, and alterations in the tear proteome. The majority of these parameters returned to baseline after ortho-k lens discontinuation, with timing potentially dependent on the amount of myopic correction, duration of ortho-k use, and age of lens fitting. Conclusions: Despite the paucity of articles describing prior ortho-k patients undergoing corneal refractive surgery, it is evident that ortho-k use may potentially cause various corneal physiological, tomographic, and biomechanical changes in patients. Therefore, clinicians are advised to serially monitor ortho-k patients' refraction, tomography, pachymetry, and corneal biomechanics until stability is achieved before considering surgery.

Determining the Relationship Between Corneal Stiffening and Tissue Dehydration After Corneal Cross-Linking.

To quantify corneal cross-linking (CXL)-induced stiffening via mechanical testing to estimate the impact of changes in hydration levels (H) and evaluate depth-dependent tissue hydration after CXL. Eighty-three porcine corneal buttons were divided into three groups: Standard protocol CXL (S-CXL), accelerated CXL (A-CXL), and untreated (nonirradiated riboflavin-only) controls. Samples were hydrated or dehydrated to modulate H and dynamic mechanical analyzer compression tests were performed to measure Young's modulus (E). To extract the solid tissue network modulus, the cornea was modeled as a biphasic material after measuring E at different H. Corneal hydration was correlated with depth-dependent tissue thickness characterized by confocal reflection microscopy (CRM). Young's modulus increased fourfold after S-CXL (0.72 ± 0.1 MPa) and threefold after A-CXL E (0.53 ± 0.12 MPa) versus controls (0.17 ± 0.045 MPa). However, H decreased from 4.07 ± 0.35 in controls to 2.06 ± 0.2 after S-CXL and 2.79 ± 0.12 after A-CXL. After H modulation and biphasic mechanical modeling, Young's modulus for corneal solid tissue network showed only a 1.8-fold increase after S-CXL (2.25 MPa) and 1.5-fold increase after A-CXL (1.85 MPa) versus controls (1.22 MPa). With CRM, the overall thickness of the corneal tissue was found to linearly correlate to hydration H as expected. No appreciable depth dependence of hydration-induced thickness changes throughout the corneal buttons were observed. Corneal tissue hydration changes significantly impact measured corneal stiffness after CXL using mechanical testing. Not considering H leads to major overestimation of the stiffening effect of the CXL procedure. Depth-dependence of corneal thickness because of changing hydration is strongly dependent on the integrity of the tissue.

Corneal Artificial Endothelial Layer (EndoArt): Literature Review and Our Experience

Background/Objectives: The objective of this study was to examine the morphological corneal changes and outcomes following the implantation of an artificial endothelial layer (EndoArt) in patients with chronic corneal oedema. Methods: A systematic review of the literature was conducted alongside a detailed analysis of two clinical cases with chronic corneal oedema that were treated using EndoArt. Our experience with these two cases is included to provide practical insights and real-world outcomes. Results: Across the 24 cases reported (including the two presented here), an analysis was possible in 23 cases. Notably, 82% of patients had undergone at least one previous corneal transplant, with 39% having undergone three or more transplants. Additionally, 78% of cases had ocular comorbidities, with glaucoma surgery being the most prevalent (83%), which could have impacted visual outcomes. The follow-up period ranged from 3 to 17 months with a median of 3 months. After EndoArt implantation, the average reduction in the central corneal thickness (CCT) was 29%, and the rebubbling rate was 47.8%, with some cases requiring no rebubbling, while others required it up to 100% of the time. Visual acuity significantly improved from a mean best-corrected visual acuity (BCVA) value of 1.61 ± 0.5 logMAR to 1.07 ± 0.59 logMAR (p < 0.001). The CCT decreased from 771 ± 146 µm to 580 ± 134 µm (p < 0.001). These findings are consistent with our experience. Conclusions: EndoArt shows promise as an alternative treatment for chronic corneal oedema in complex cases where conventional corneal transplantation has failed or carries a high risk of failure. The morphological changes observed using anterior segment optical coherence tomography (OCT) and in vivo confocal microscopy (IVCM) were similar to those reported after endothelial keratoplasty, with the notable exception of the absence of the hyper-reflective donor–host interface.

The Role of Eye Movements in the Process of Silicone Oil Emulsification After Vitreoretinal Surgery

Emulsification is a feared and common complication of the use of silicone oil (SO) as tamponade fluid after vitrectomy as it potentially associated with significant risks to ocular health, including elevated intraocular pressure (IOP), glaucoma, corneal and retinal changes. The aim of this study was to investigate the role and interplay of physical factors on the formation of SO emulsion. Experiments were performed in a model of the vitreous chamber with a realistic shape, filled with SO and an aqueous solution containing different concentrations of albumin, an endogenous protein known to modify the interfacial properties between SO and aqueous solutions. The model was subjected to harmonic and saccadic rotations and kept at body temperature. Results indicated that no emulsions were detected in the absence of albumin in the aqueous solution, while the presence of the protein facilitated emulsion formation, acting as a surfactant. Mechanical energy from eye movements was also found to be a key mechanism to produce emulsification, with higher mechanical energy provided to the system leading to smaller droplet sizes. The emulsions formed were stable over extended times. This study highlights the complex interplay of factors influencing SO emulsification in the vitreous chamber. A better understanding of the mechanisms underlying SO emulsification is crucial for developing strategies to mitigate SO emulsion and the related complications.

Chemotherapy Induced Corneal Changes Assessed by Corneal Confocal Microscopy: A Review

The eye, and the cornea in particular, is a common site of chemotherapy induced toxicity, and ocular side effects of both traditional and novel agents have been reported. Corneal confocal microscopy (CCM) is an in vivo technique that allows for the study of all the corneal layers in an easy, non-invasive and reproducible way via the direct visualization of corneal cell morphologies as well as of sub-basal nerve plexus. Thus, it represents a useful way to identify and monitor chemotherapy induced corneal alterations. This work aims to review the use of CCM in identifying corneal toxicity secondary to chemotherapy treatment, as regards both corneal nerves alterations in the setting of chemotherapy induced peripheral neuropathy (CIPN) and other corneal structure changes, particularly involving the corneal epithelium.

Findings in Corneal Endothelium by Confocal and Specular Microscopy in Patients with Fuchs Uveitis Syndrome Undergoing Phacoemulsification

ABSTRACT Purpose To compare corneal endothelial changes in patients with Fuchs Uveitis Syndrome (FUS) undergoing phacoemulsification surgery using confocal and specular microscopy. Methods We included 14 patients with unilateral FUS and cataracts who underwent phacoemulsification surgery in a Mexican referral center for inflammatory eye diseases. Preoperative confocal and specular microscopies were conducted, establishing baseline images for subsequent analyses. Surgery on the FUS eye was performed by a single surgeon and an intraocular lens was implanted in all cases. Both specular and confocal microscopy were repeated 6 months after FUS eye surgery and compared with baseline images. We used Image J to do a manual segmentation of KP and determine their density for further analysis hence developing a new tool for confocal microscopy image analysis. Results All patients underwent uneventful phacoemulsification surgery in the FUS eye. There was no significant change in endothelial cell density (ECD) from 2257 (±508.2) cells/mm2 preoperatively to 2214 (±535.1) cells/mm2 postoperatively (p = 0.809). Confocal microscopy revealed a decrease in Keratic Precipitate Density (KPD) from a median of 1413 (±2809.7) KPs/mm2 preoperatively to a median of 685.5 (1527.9) KPs/mm2 postoperatively (p = 0.036). Conclusions Phacoemulsification surgery in patients with FUS produces no significant loss of endothelial cells and morphological changes that can be detected by confocal and specular microscopy. We found a reduction in KPD 6 months after surgery on confocal microscopy. Additionally, our manual segmentation technique for KPs utilizing Image J offers a novel and practical approach for confocal microscopy image analysis.

Corneal and intraocular pressure changes associated to the circadian rhythms: a narrative review.

To synthesize the current body of research regarding the diurnal variations in intraocular pressure (IOP) and corneal biomechanical and morphological parameters, highlighting their significance in various eye conditions. A comprehensive review of studies on the diurnal variations of IOP and corneal parameters was conducted. Tonometry findings from various studies were assessed, including the Goldmann applanation tonometry (GAT) and non-contact tonometers. Data on the variations in central corneal thickness (CCT), corneal curvature, and corneal biomechanics measured by the Ocular Response Analyzer system across different population groups was extracted and analyzed. In both healthy subjects and those with Fuchs dystrophy, IOP and CCT demonstrate marked diurnal declines. GAT remains the gold standard for tonometry, with the highest reliability. However, its measurements are influenced by CCT. Keratoconus patients and those with pseudoexfoliation showed significant diurnal variations in IOP. The biomechanical parameters, especially corneal hysteresis (CH) and the corneal resistance factor (CRF), largely remain stable throughout the day for most of eye conditions, with some exceptions. Notably, the corneal morphology diurnal variation, particularly curvature, yielded mixed conclusions across studies. Circadian rhythms significantly influence various corneal parameters, most notably IOP and CCT. Further studies should emphasize standardized approaches larger sample sizes, and delve deeper into less-explored areas, such as the effects of orthokeratology lenses on diurnal biomechanical shifts.

Corneal Endothelial Changes in Chinese Patients with Fuchs’ Uveitis Syndrome

ABSTRACT Purpose To analyze the changes of corneal endothelial cells in Chinese patients with unilateral Fuchs’ uveitis syndrome (FUS) and investigate the factors relevant to these changes. Methods Bilateral specular microscopic examination was performed in 459 Chinese patients with unilateral FUS from April 2008 to April 2023. The affected eyes constituted the study group, while the contralateral eyes served as controls. Results The median values of endothelial cell density (ECD), cell count, total cell size, and hexagonality were significantly lower in the FUS eyes compared to the control eyes (p < 0.001). The median values of average cell size, maximum cell size, SD of cell size, and CV were significantly higher in the FUS eyes compared to the control eyes (p < 0.001). Central ECD showed a negative correlation with age (r = −0.339; p < 0.001), maximum IOP (r = −0.127; p = 0.006), and the interval since symptom onset (r = −0.172; p < 0.001). The ECD was lower in eyes with ocular hypertension compared to those without ocular hypertension (p < 0.001). Eyes with KPs distributed on the central corneal endothelium had a significantly lower ECD than those with KPs distributed diffusely or KPs distributed triangularly on the inferior corneal endothelium (p = 0.006). Conclusion Our findings suggest decreased ECD, increased cell size, and morphological alterations in the affected eyes of Chinese patients with FUS. The reduction in ECD is correlated with age, elevated IOP, the interval since symptom onset, and the distribution of KPs.

Quantitative Evaluation of the Effects of Blepharoplasty on Visual Field, Corneal Changes, and Cosmetic Appearance.

Blepharoplasty is an important eyelid surgical procedure, involving aesthetic and functional changes to the eyelids. The aim of this study is to investigate the effects of upper eyelid blepharoplasty on changes in the visual field, corneal changes, and cosmetic appearance. This study was performed with preoperative and postoperative facial photographs of 32 patients who underwent bilateral blepharoplasty. Marginal reflex distance (MRD1), percentage of corneal exposure area (CEA), and brow height (BH) were obtained from photographs. intraocular pressure (IOP) and ocular biometric parameters were also obtained. The morphometric and ocular parameters obtained from preoperative, postoperative first-month, and postoperative third-month patients were compared using repeated measures ANOVA test. Significant differences in MRD1, CEA, and BH were observed between preoperative, postoperative first-month, and postoperative third-month patients. Improvements were observed in left axis and right corneal astigmatism axis measurements in the postoperative third month compared with preoperative measurements, and the positive change was statistically significant (P=0.020, P=0.036). Upper eyelid blepharoplasty could provide satisfactory functional and aesthetic outcomes by contributing to the improvement of pseudoptosis and reduction in eyebrow height postoperatively.

Corneal topographic changes in thyroid eye disease

Background Thyroid eye disease (TED) causes lid retraction, extraocular muscle enlargement, and tear film changes, which can affect corneal topography. Aim To assess the corneal topographic changes associated with TED and relate these changes to disease activity and severity. Patients and methods This prospective cross-sectional case-control study was carried out on 50 eyes of 25 patients aged less than or equal to 50 years old, both sexes, diagnosed with TED and present or past serological evidence for thyroid disease (TED group). Patients were divided into two groups: the TED group: 30 eyes of 15 patients with TED and the control group: 20 eyes of 10 patients with age-matched and sex-matched without TED. Results In the TED group, axial proptosis was negatively correlated with minimal corneal thickness. Both upper and lower lid infrared meibography showed a positive correlation with axial proptosis. Active patients had considerably greater Baiocchi-Calossi-Versaci front and upper lid meibomian glands loss than inactive cases. In moderate to severe instances, upper and lower lid meibomian gland loss was much greater than in mild cases. Baiocchi-Calossi-Versaci front, Baiocchi-Calossi-Versaci back, Baiocchi-Calossi-Versaci total, and meibomian glands loss were considerably greater in TED than the control group. The TED group had significantly lower flat, steep, and average keratometry than the control group. Conclusion Corneal anterior surface flattening is the most characteristic topographic change in TED not related to disease activity or severity. TED increases meibomian gland loss, which is a major factor of ocular surface alteration in TED.

Corneal nerve changes by anti-glaucoma medications examined by in vivo confocal microscopy.

To evaluate the effects of antiglaucoma eye drops on corneal nerves by in vivo confocal microscopy (IVCM). This study comprised 79 patients diagnosed with glaucoma and 16 healthy control individuals. Among the glaucoma patients, 54 were treated with medication, while 25 remained untreated. Central corneal images were evaluated by IVCM, and then ACCMetrics was used to calculate the following parameters: corneal nerve fiber density (CNFD), branch density (CNBD), fiber length (CNFL), total branch density (CTBD), fiber area (CNFA), fiber width (CNFW), and fractal dimension (CNFrD). The correlation between IVCM parameters and drugs was evaluated using non-parametric measurements of Spearman's rank correlation coefficient. The CNFD was reduced in glaucoma groups compared to healthy subjects (P<0.01). Patients using anti-glaucoma medications exhibited poorer confocal parameters compared to untreated patients. As the number of medications and usage count increased, CNFD, CNBD, CNFL, CTBD, CNFA, and CNFrD experienced a decline, while CNFW increased (all P<0.01). For the brinzolamide-therapy group, there was a significant decrease in CNFD and CNFL compared to the other monotherapy groups (P<0.001). In the absence of medication, CNFD in males was lower than that in females (P<0.05). Among patients under medication therapy, CNFD remained consistent between males and females. Antiglaucoma eye drops affect the microstructure of corneal nerves. IVCM and ACCMetrics are useful tools that could be used to evaluate the corneal nerve changes.

Corneal microstructural changes of precise CHST6 gene mutation: a case series

BackgroundMacular corneal dystrophy (MCD) is an inherited, autosomal recessive disorder of defective keratan sulfate (KS) metabolism. It is caused by the mutations in carbohydrate sulfotransferase 6 gene (CHST6) which is essential for the sulfation of KS. Unlike the western world, MCD is the most common corneal stromal dystrophy in India, especially in south Indian population; it could be due to high frequency of consanguineous marriages.Case presentationThis study presents the clinical findings of one North Indian MCD family, including 6 patients and 3 unaffected relatives. We used slit lamp examination and in vivo confocal microscopy for assessment. Mutation screening was performed with Sanger sequencing, and corneal structure was analyzed through histochemistry and immunohistochemistry. Our comparative findings revealed that all the patients identified with the deletion of major portion of CHST6 that included the Open Reading Frame (ORF). Although all the patients showed significantly reduced central corneal thickness (CCT-250 μm), a drastic decrease in stromal keratocyte count, and depletion of Bowman’s layer compared to controls.ConclusionsThis study first time revealed that MCD patients from one family with a deletion of major portion of CHST6 that included ORF leads to severe corneal morphological changes.

A comparative study on the phaco time and corneal endothelial count in phacoemulsification using the stop &amp; chop and divide &amp; conquer techniques in Indian eyes

Cataract, a leading cause of curable blindness requires surgical management. Endothelium which is crucial for corneal transparency gets injured during intraocular surgeries like phacoemulsification. Various studies have compared the impact of different techniques of phacoemulsification on endothelium. But few studies conclude that Phaco time &amp; endothelial loss is lesser in Stop &amp; Chop than Divide &amp; Conquer technique. An Interventional study involving 30 eyes in Group A (Stop &amp; Chop) and 30 in Group B (Divide &amp; Conquer) with Nuclear sclerosis grade II and III, excluding any pre-existing corneal diseases and Glaucoma was conducted in a tertiary care teaching hospital. All pre-operative parameters were similar in both groups. Post-operative values of best corrected visual acuity (BCVA), intra ocular pressure (IOP), endothelial cell count, central corneal thickness (CCT), Absolute Phaco time were recorded. Data entered in Excel sheets and analysed with SPSS. Paired, Unpaired t tests were used. P value &amp;#60;0.05 was statistically significant. Mean Absolute Phaco time for Group A was shorter (25.10±10.54 s) than that for Group B (44.20± 6.94 s) with statistical significance (p&amp;#60;0.05). Mean cell loss &amp; changes in endothelium were higher in Group B than Group A (p&amp;#60;0.05). Absolute Phaco time was shorter in Stop &amp; Chop than Divide &amp; conquer as well as the corneal endothelial damage and changes were lesser in Group A. Hence Stop &amp; Chop technique of phacoemulsification is recommended for less corneal morbidity.

Longitudinal Analysis of Tear Cytokine Ratios in Association with Dry Eye Signs and Symptoms in the Dry Eye Assessment and Management (DREAM) Study

Purpose To extend cross-sectional data on cytokine ratios (CRs) in dry eye disease (DED) signs by investigating longitudinal change in pro- to anti-inflammatory CRs and associations with change in DED signs and symptoms. Methods Secondary analysis of fifty-four subjects [mean age 57.3 (SD 13.2) years, 85.2% female; 68.5% white] with ≥ 4 uL pooled tear volumes at months 0, 6, and 12. Pro-inflammatory (IL-1b, IL-6, IL-8, IL-17A, IFN-g, and TNF-a) to anti-inflammatory (IL-6, IL-10) cytokine ratios (CR) were calculated. DED signs (corneal and conjunctival staining scores, tear break-up time, Schirmer test, Meibomian gland plugging, tear osmolarity, composite sign severity score) and symptoms [Ocular Surface Disease Index (OSDI)] were measured. Changes over time in DED signs, symptoms, and CRs were evaluated using longitudinal models. Correlations between changes in CR and changes in DED signs and symptoms were evaluated using Spearman correlation coefficients (rho). Results DED signs which improved over time (p < 0.001) included corneal and conjunctival staining score, tear break-up time, tear osmolarity, and composite sign severity score. Using IL-10 as anti-inflammatory, changes in corneal and conjunctival staining and composite severity score significantly correlated with changes in pro- to anti-inflammatory CRs from month 0 to 6 (|rho|: 0.29-0.45, p: 0.003-0.04) but not between month 0 to 12 (|rho|: 0.01 to 0.24, all p > 0.08). DED symptoms decreased across one year (p < = 0.001) for all OSDI measures; these changes did not correlate with changes in CRs (|rho|: 0.00 to 0.29, all p > 0.04). Conclusions Improvement in some DED signs across one year correlated weakly with decreases in pro- to anti-inflammatory CRs, in alignment with the understanding of DED as inflammatory. CRs may provide greater insight than absolute tear cytokine concentrations as possible DED biomarkers. Additional studies that provide standardized clinical information and tear collection and analysis are needed to validate CRs in DED.

Corneal vascularisation and haemorrhage associated with netarsudil drops

ABSTRACT We report an interesting case of superficial corneal vascularization along with haemorrhages and microcystic edema confined to the inferior cornea in a female patient that are clearly attributed to netarsudil eye drops which she had been instilling for the last 8 weeks . Complete regression of all these corneal changes was noted after 3 months of discontinuation of this Rho kinase inhibitor. This is a unique finding and to our knowledge ; has not been reported so far.

Corneal changes after large (9mm) lateral rectus muscle recession measured with Pentacam®

ABSTRACT Introduction: The aim of this study was to evaluate alterations in corneal astigmatism, axial anterior corneal curvature, anterior chamber depth, and central corneal thickness (CCT) two months after the unilateral recession of lateral rectus muscle in children. Methods: This prospective study included 37 children with intermittent exotropia who would undergo unilateral lateral rectus muscle recession. All measurements were performed using Pentacam®. Comparisons were made between the operated and fellow unoperated eyes, pre- and post-operatively. The assessment was made for changes in the radius of axial curvature on major meridians at 3 and 3.5 mm from the optical corneal center in the mid-peripheral zone. Astigmatism changes of the anterior and posterior corneal surface were calculated using vector analysis software (astigMATIC®). The interaction between age or CCT and postoperative changes in anterior and posterior surface corneal astigmatism were examined with ANOVA model. Results: In the intervention group, changes in anterior and posterior corneal surface astigmatism were statistically significant, with a mean increase of 0.56Dx90 and 0.08Dx87, respectively. In the mid-peripheral corneal zone, an increase was observed in the radius of anterior corneal axial curvature, more evident temporal 3 and 3.5 mm from the corneal center on the horizontal meridian, with corresponding decrease superiorly and inferiorly at 3 and 3.5 mm from the corneal center on the vertical meridian. Discussion: The changes in total astigmatism of the operated eyes are mainly attributed to the anterior corneal surface. These changes are associated with flattening in the 180 meridian of the cornea, leading to a shift to “with-the-rule” astigmatism.

Corneal densitometry changes post-CXL for keratoconus: Comparative evaluation of epithelium-off, contact lens-assisted, and transepithelial techniques.

To evaluate changes in corneal backscattering after collagen cross-linking (CXL) for progressive keratoconus and compare its course with different techniques - standard epithelium-off CXL (SCXL), contact lens-assisted CXL (CACXL), and transepithelial CXL (TECXL). Advanced Eye Center, Post Graduate Institute of Medical Education and Research, Chandigarh, India. Retrospective comparative study. Ninety-four eyes (SCXL: 47, CACXL: 30, and TECXL: 17) were compared. Corneal haze was quantified using Scheimpflug tomography, pre- and post-CXL at 1, 3, 6, and 12 months. The baseline mean density score of the central anterior stromal layer was 16.14 ± 7.07, 15.85 ± 7.89 and 15.89 ± 7.21 in SCXL, CACXL, and TECXL groups, respectively (P 0.93). After SCXL, the score increased to 28.83 and 31.34 at 1 and 3 months, respectively (both P < 0.001) and dropped at 6 months (28.66, P < 0.001) and 12 months (23.72, P 0.003). Post-CACXL, the mean densitometry peaked at 3 months (20.35, P 0.14) and returned toward baseline at 6 months (18.82, P 0.15). After TECXL, it increased slightly at 1 month (18.47, P 0.17), decreased at 3 months (14.88, P 0.7), and plateaued over 1 year. No correlation with visual acuity was seen. Corneal haze increased significantly after SCXL, peaking at 3 months, declining over 6-12 months, and returning to baseline at 12 months. In contrast, post-TECXL and -CACXL, there was an insignificant increase in anterior corneal haze, which returned to baseline within 3-6 months.

Corneal Biomechanical Changes in Patients with Inherited Retinal Diseases.

Inherited retinal diseases (IRDs) are a group of degenerative disorders of the retina, that can be potentially associated with changes in the anterior segment, but their prevalence and impact are not known. Exploring these concomitant ophthalmologic changes with biomechanical assessment may help identify other non-retina causes of vision loss in these patients, such as corneal ectasia or susceptibility to glaucoma. This study aimed to measure and compare corneal biomechanics in patients with and without IRDs. A total of 77 patients (154 eyes) with IRD were recruited as the study group. The control group consisted of 77healthy adults (154 eyes) with matched age and sphere equivalents. All participants underwent a comprehensive assessment including corneal tomography (Pentacam®) and biomechanical assessment (Corvis ST®). A total of 4 second-generation biomechanical parameters and 3 indexes were collected: Ambrosio Relational Thickness (ARTh), Deflection Amplitude Ratio Max (DARM), Integrated Radius (IR) and Stiffness Parameter at Applanation (SP-A1), the final deviation value D of the Belin/Ambrosio Enhanced Ectasia Display (BAD-D), Corvis Biomechanical Index (CBI) and Tomographic Biomechanical Index (TBI). For IRD patients, there was a higher DARM (p < 0.001), lower ARTh (p < 0.001), higher CBI (p < 0.001), higher TBI (p<0.001), and higher BAD-D (p < 0.001) compared to the control group. Regarding discrimination of healthy subjects and IRD patients, ARTh was the most sensitive parameter. The results showed that IRD patients tend to have softer corneal behaviour, compared to eyes without pathology, which may predispose patients to corneal ectasia or glaucoma development. ARTh could be used to screen IRD patients if a non-retina cause of vision loss is suspected.

The Necroptosis Pathway Is Upregulated in the Cornea in Mice With Ocular Graft-Versus-Host Disease.

To identify molecular signatures specific for ocular graft-versus-host disease (GVHD) by proteomic analysis of corneas from mice with GVHD. We identified differentially expressed proteins (DEPs) in corneal samples from GVHD model mice and syngeneic control mice 4 weeks after bone marrow transplantation. Data-independent acquisition analysis was performed on individual samples, and the roles of DEPs in biological pathways related to GVHD were evaluated via bioinformatics and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Three important signaling pathways were upregulated in the cornea in mice with GVHD: (1) the necroptosis pathway, (2) the mitogen-activated protein kinase (MAPK) pathway, and (3) as previously reported, the neutrophil extracellular trap (NET) pathway. In those signaling pathways, we identified new upregulated molecules, including (1) receptor-interacting protein kinase 1 (RIPK1), RIPK3, interferon regulatory factor 9, the interferon-induced double-stranded RNA-activated protein kinase lipoxygenase, and high mobility group box1 (HMGB1) which are damage-associated molecular patterns (DAMPs) in the necroptosis pathway; (2) the sequentially upregulated interleukin 1 (IL-1) receptor-associated kinase (IRAK), an evolutionarily conserved signaling intermediate in the Toll pathway (ECSIT), and p38, which is downstream of the IL-1 receptor and increased CDC42/Rac (Rac2), a Rho family GTPase in the MAPK pathway; and (3) the integrin components CR3 and macrophage-1 antigen (MAC-1), which are DAMPs, and the pyroptosis-related protein gasdermin D (GSDMD) in the NET pathway. These novel molecules may help researchers elucidate the pathogenesis of GVHD and identify new therapeutic targets for corneal changes in patients with ocular GVHD.

A Review on current developments in early ectasia detection – the corneal biomechanical analysis

Purpose. Topographic and tomographic parameters are often not sufficient for early diagnosis of corneal changes. Pathological processes begin in the microstructure before topographic/tomographic abnormalities become apparent. Biomechanical parameters correlate strongly with microscopic structural parameters, while they can be used for early detection of ectasia. Material and Methods. This review summarizes the biomechanical properties of the cornea with regard to the detection of early ectasia and keratoconus. Air-puff tonometry is used to record the deformation behavior of the cornea and to derive corneal deformation parameters and biomechanical indices for ectasia detection. Results. The biomechanical parameters in keratoconus differ significantly from those of healthy eyes. Changes in the cornea can be detected even before topographic or tomographic changes. Artificial intelligence approaches support the merging of the numerous available data on single parameters for appropriate handling in clinical practice. Conclusion. Examination of corneal biomechanics using air-puff tonometry is a new method to detect possible early changes in the tissue. The biomechanical parameters, especially those of Scheimpflug-based air-puff tonometry, reveal changes before they are visible on topography or tomography. This is of great importance in refractive surgery, but also in the management of keratoconus.