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Rho kinase (ROCK) inhibitors have emerged as a key therapeutic class of interest in ophthalmology over the last decade. Promising in vitro studies laid the foundations for the development of novel therapeutic agents that target the ROCK signalling pathway in ocular disease, with subsequent clinical trials supporting their use. Corneal endothelial disease, glaucoma, and vitreoretinal disease are the major pathologies in which ROCK inhibitors have been investigated to date. Ripasudil and netarsudil represent the current leaders in this pharmaceutical group, having been extensively validated and approved for use in glaucoma in some countries. Less substantial evidence exists for fasudil in ophthalmic use. ROCK inhibitors are also increasingly used in cultured endothelial cell grafting and as an adjunct to aid in endothelial cell migration and replication in Descemet's stripping procedures or Descemet's membrane injuries. This review has synthesised both established and emerging research to provide a practical guide to prescribing in this drug class. Drug efficacies, side effect profiles, and the demographic and clinical characteristics of appropriate drug candidates are discussed. [ABSTRACT FROM AUTHOR]

Purpose Posterior corneal vesicles (PCVs) have clinical features that are similar to posterior polymorphous corneal dystrophy (PPCD). To help determine whether there is a shared genetic basis, we screened 38 individuals with PCVs for changes in the three genes identified as causative for PPCD. Methods: We prospectively recruited patients for this study. We examined all individuals clinically, with their first‐degree relatives when available. We used a combination of Sanger and exome sequencing to screen regulatory regions of OVOL2 and GRHL2, and the entire ZEB1 coding sequence. Results: The median age at examination was 37.5 years (range 4.7–84.0 years), 20 (53%) were male and in 19 (50%) the PCVs were unilateral. Most individuals were discharged to optometric review, but five had follow‐up for a median of 12 years (range 5–13 years) with no evidence of progression. In cases with unilateral PCVs, there was statistically significant evidence that the change in the affected eye was associated with a lower endothelial cell density (p = 0.0003), greater central corneal thickness (p = 0.0277) and a steeper mean keratometry (p = 0.0034), but not with a higher keratometric astigmatism or a reduced LogMAR visual acuity. First‐degree relatives of 13 individuals were available for examination, and in 3 (23%), PCVs were identified. No possibly pathogenic variants were identified in the PPCD‐associated genes screened. Conclusion: We found no evidence that PCVs share the same genetic background as PPCD. In contrast to PPCD, we confirm that PCVs is a mild, non‐progressive condition with no requirement for long‐term review. However, subsequent cataract surgery can lead to corneal oedema. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of tobacco use on corneal thickness and corneal endothelial health. Methods: We searched the PubMed/MEDLINE, EMBASE, the Cochrane Central and all affiliated databases of the Web of Science on 20 July 2020. Two authors reviewed the studies and extracted the data in an independent fashion. Studies were reviewed qualitatively in the text, and central corneal thickness (CCT) and corneal endothelial characteristics (endothelial cell density, endothelial cell variability, average of endothelial cell size and endothelial cell hexagonality) were introduced for quantitative analyses. Results: Eighteen studies (2077 were smokers and 6429 non‐smokers) were identified, of which 17 studies provided data eligible for one or more of the quantitative analyses. When compared to non‐smokers, smokers had a higher CCT (+3.3 μm, 95% CI: +0.9 to +5.7 μm, p = 0.007) and a lower endothelial cell density (−140 cells/mm2, 95% CI: −30 to −250 cells/mm2, p = 0.01). Other corneal endothelial measures did not differ significantly. Conclusion: Tobacco use is associated with a higher CCT and lower corneal endothelium cell density, but the clinical impact of these findings is small. Further studies are warranted on patients with a priori poor corneal health, where smoking may constitute an important risk of further progression, for example upon anterior segment surgery. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the 3‐year surgical outcome of the sulcus fixation of Baerveldt glaucoma implant (BGI), focusing on corneal damage. Methods: This prospective observational study included 37 patients who underwent a median of two previous glaucoma surgeries and sulcus fixation of BGI for the first time. Each patient's intraocular pressure (IOP), glaucoma drug score, corneal endothelial cell density (ECD), and logMAR‐converted best‐corrected visual acuity (VA) were measured preoperatively and postoperatively until 36 months after surgery. Complete success was defined as reduced IOP (5–21 mmHg and >20% rate), without corneal damage (postoperative development of decompensation, unmeasurable ECD, or reduction in ECD of >20%), without loss of light perception, and without additional surgery requirement. Qualified success was defined by excluding the corneal criteria from complete success. Results: A total of 51% (19/37) patients experienced complete treatment success, whereas 86% (32/37) had qualified success. The median IOP (glaucoma drug score) decreased from 26 mmHg (5) to 15 mmHg (2) at three years postoperatively. The median postoperative ECD (reduction rate) decreased from 1838 cells/cm2 preoperatively to 1587 cells/mm2 (14%) at one year, 1358 cells/mm2 (26%) at two years, and 1228 cells/mm2 (33%) at three years postoperatively. One month after surgery, the VA was significantly reduced from preoperative values but did not decline after that. Conclusion: Sulcus fixation of BGI was effective for IOP reduction. However, ECD decreased over time. [ABSTRACT FROM AUTHOR]

Corneal transplantation is currently the most effective treatment to restore corneal clarity in patients with endothelial disorders. Endothelial transplantation, either by Descemet membrane endothelial keratoplasty (DMEK) or by Descemet stripping (automated) endothelial keratoplasty (DS(A)EK), is a surgical approach that replaces diseased Descemet membrane and endothelium with tissue from a healthy donor eye. Its application, however, is limited by the availability of healthy donor tissue. To increase the pool of endothelial grafts, research has focused on developing new treatment options as alternatives to conventional corneal transplantation. These treatment options can be considered as either 'surgery‐based', that is tissue‐efficient modifications of the current techniques (e.g. Descemet stripping only (DSO)/Descemetorhexis without endothelial keratoplasty (DWEK) and Quarter‐DMEK), or 'cell‐based' approaches, which rely on in vitro expansion of human corneal endothelial cells (hCEC) (i.e. cultured corneal endothelial cell sheet transplantation and cell injection). In this review, we will focus on the most recent developments in the field of the 'cell‐based' approaches. Starting with the description of aspects involved in the isolation of hCEC from donor tissue, we then describe the different natural and bioengineered carriers currently used in endothelial cell sheet transplantation, and finally, we discuss the current 'state of the art' in novel therapeutic approaches such as endothelial cell injection. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to evaluate the corneal endothelium in patients with chronic obstructive pulmonary disease (COPD) using a specular microscope. Methods: The right eyes of 64 patients with a COPD diagnosis and 65 healthy individuals were evaluated. Cell density (CD) (cell/mm2), corneal thickness (CT) (μ), hexagonal cell ratio (%), and coefficient of variation (cell area standard deviation/mean cell area, μm2) were analyzed by specular microscopy (SM). Results: The CT was significantly reduced in the COPD group compared with the control group (P = 0.021). Moreover, a significant difference was found between the COPD group and the control group in terms of corneal endothelial CD (P = 0.011), hexagonal cell ratio (P = 0.008), and coefficient of variation (P = 0.012). Conclusion: The corneal endothelial structure was significantly deteriorated in patients with COPD compared with the control group. SM is a valuable method that could be used in treatment and follow‐up of corneal endothelium in patients with COPD. [ABSTRACT FROM AUTHOR]

Cornea is an avascular and transparent tissue that focuses light on retina. Cornea is supported by the corneal‐endothelial layer through regulation of hydration homeostasis. Restoring vision in patients afflicted with corneal endothelium dysfunction‐mediated blindness most often requires corneal transplantation (CT), which faces considerable constrictions due to donor limitations. An emerging alternative to CT is corneal endothelium tissue engineering (CETE), which involves utilizing scaffold‐based methods and scaffold‐free strategies. The innovative scaffold‐free method is cell sheet engineering, which typically generates cell layers surrounded by an intact extracellular matrix, exhibiting tunable release from the stimuli‐responsive surface. In some studies, scaffold‐based or scaffold‐free technologies have been reported to achieve promising outcomes. However, yet some issues exist in translating CETE from bench to clinical practice. In this review, we compare different corneal endothelium regeneration methods and elaborate on the application of multiple cell types (stem cells, corneal endothelial cells, and endothelial precursors), signaling molecules (growth factors, cytokines, chemical compounds, and small RNAs), and natural and synthetic scaffolds for CETE. Furthermore, we discuss the importance of three‐dimensional bioprinting strategies and simulation of Descemet's membrane by biomimetic topography. Finally, we dissected the recent advances, applications, and prospects of cell sheet engineering for CETE. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine the relationship between corneal cellular structures and biomechanical deformation parameters in keratoconic (KC) and healthy eyes. Methods: In this prospective comparative study, 29 eyes of 29 KC patients were age‐ and gender‐matched with 28 eyes of 28 healthy individuals using frequency matching. Corneal parameters examined included the density of basal epithelial cells, anterior keratocytes, posterior keratocytes and endothelial cells as assessed by in vivo corneal confocal microscopy (HRT III‐RCM, Heidelberg Engineering, www.heidelbergengineering.com). Additionally, the coefficient of variation of endothelial cell size (CV) and the percentage of hexagonal endothelial cells (HEX%) were measured by specular microscopy (Konan NSP‐9900, Konan Medical, www.konanmedical.com). Further, biomechanical deformation parameters were derived from Corvis Scheimpflug Technology (Corvis ST, Oculus, www.oculus.de). All cellular and biomechanical deformation parameters in KC and normal groups were compared, and the relationship between cellular and biomechanical parameters calculated. Results: In the KC group, the highest concavity (HC) delta arc length and maximum delta arc length were associated with endothelial cell density (Beta = −0.39, p = 0.03 and Beta = −0.60, p ˂ 0.001, respectively). Furthermore, there was a significant association between HC deflection length and HEX% (Beta = −0.67, p = 0.001). In the normal group, HC delta arc length and HC deflection length were significantly associated with endothelial cell density (Beta = 0.46, p = 0.02; and Beta = −0.51, p = 0.01, respectively). HC time, HC deformation amplitude and applanation 1 delta arc length were associated with CV (Beta = 0.50, p = 0.01; Beta = 0.27, p = 0.009; and Beta = −0.57, p = 0.002, respectively). Applanation 1 and applanation 2 deformation amplitudes were associated with HEX% (Beta = −0.49, p = 0.005; and Beta = −0.46, p = 0.02). Conclusions: Biomechanical deformation parameters were significantly correlated with endothelial cell properties in both KC and normal groups, thereby indicating the importance of the integrity of endothelial cells to the biomechanical properties of both KC and normal corneas. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether excimer laser ablation of guttae is a viable strategy for removal of diseased tissue in Fuchs' endothelial corneal dystrophy (FECD) on excised human Descemet membranes and whether an excimer laser‐created wound on healthy human corneas ex vivo is recolonized with corneal endothelial cells. Methods: Descemet membranes of FECD patients and corneal endothelium of normal human corneas were ablated ex vivo using an excimer laser licensed for glaucoma surgery. Specimens were kept in cell culture medium supplemented with 10 μm of rho‐kinase inhibitor ripasudil. Corneal endothelial cell regeneration was observed using light and electron scanning microscopy. Furthermore, the whole corneal samples were evaluated by haematoxylin/eosin staining and immunohistochemical analysis using antibodies against Na+/K+‐ATPase. Results: Guttae and corneal endothelium could be ablated with an excimer laser without total ultrastructural damage to the Descemet membrane or stroma. Nearly complete endothelial wound closure was accomplished after 26–38 days in treated corneas. Light and electron scanning microscopy suggested the establishment of a layer of flat endothelial cells. Additionally, Na+/K+‐ATPase expression could only be observed on the inner side of the Descemet membrane. Conclusion: Our proof of concept study demonstrated that excimer lasers can be used to ablate diseased tissue from excised FECD Descemet membranes ex vivo. Additionally, corneal endothelial cells recolonize a previously ablated endothelial area in healthy human corneas ex vivo under treatment with ripasudil. Thus, our results are the first experimental basis to further investigate the feasibility of an excimer laser ablation as a graftless FECD treatment option. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to establish a standardized in vitro phacoemulsification damage model for future investigations of the effects of phacoemulsification, surgical devices, protective ophthalmic viscoelastic devices (OVDs), irrigation solutions and other aspects related to cataract phacoemulsification surgery on the corneal endothelium using porcine eyes. Methods: Thirty‐four porcine eyes were randomly assigned to three groups (phacoemulsification (n = 13), irrigation (n = 9), control (n = 12)). A total of 5 min of ultrasound energy with intermittent irrigation/aspiration was applied in the eyes of the phacoemulsification group. The eyes of the irrigation group received the identical treatment, but without the application of ultrasound energy. The control group was left untreated. All eyes were then prepared to split corneal buttons followed by 15 days of cultivation. Endothelial cell density (ECD) was assessed blinded on day 15. Results: Endothelial cell density declined significantly more until day 15 in the phacoemulsification group (2567 ± 317/267 cells/mm² (median ± 25%/75%‐quartiles), −32.5 ± 7.0/6.4%) compared to the irrigation (3450 ± 350/383 cells/mm², −11.8 ± 5.3/2.6%; p < 0.001) and the control group (3650 ± 288/258 cells/mm², −10.2 ± 3.2/4.6%; p < 0.001). Conclusion: The phacoemulsification damage model presented in this study is sensitive to phacoemulsification energy and may reliably be used to investigate various factors involved in phacoemulsification with regard to their influence on corneal endothelial cells. This method is able to replace animal experiments or in vitro cell culture experiments that often do not translate well to the in vivo situation in humans. [ABSTRACT FROM AUTHOR]

In previous work, we reported that plasma membrane potential depolarization (PMPD) provokes cortical F‐actin remodeling in bovine corneal endothelial (BCE) cells in culture, which eventually leads to the appearance of intercellular gaps. In kidney epithelial cells it has been shown that PMPD determines an extracellular‐signal‐regulated kinase (ERK)/Rho‐dependent increase in diphosphorylated myosin light chain (ppMLC). The present study investigated the signaling pathways involved in the response of BCE cells to PMPD. Differently to renal epithelial cells, we observed that PMPD leads to a decrease in monophosphorylated MLC (pMLC) without affecting diphosphorylated MLC. Also, that the pMLC reduction is a consequence of cyclic adenosine 3′,5′‐monophosphate (cAMP)/protein kinase A (PKA) activation. In addition, we found evidence that the cAMP increase mostly depends on soluble adenylyl cyclase activity. Inhibition of this enzyme reduces the effect of PMPD on the cAMP rise, F‐actin remodeling, and pMLC decrease. No changes in phosho‐ERK were observed, although we could determine that RhoA undergoes activation. Our results suggested that active RhoA is not involved in the intercellular gap formation. Overall, the findings of this study support the view that, differently to renal epithelial cells, in BCE cells PMPD determines cytoskeletal reorganization via activation of the cAMP/PKA pathway. [ABSTRACT FROM AUTHOR]

Background: Multipotent neural crest cells (NCC) contribute to the corneal endothelium and keratocytes during ocular development, but the molecular mechanisms that underlie this process remain poorly understood. We performed RNA‐Seq analysis on periocular neural crest (pNC), corneal endothelium, and keratocytes and validated expression of candidate genes by in situ hybridization. Results: RNA‐Seq profiling revealed enrichment of genes between pNC and neural crest‐derived corneal cells, which correspond to pathways involved in focal adhesion, ECM‐receptor interaction, cell adhesion, melanogenesis, and MAPK signaling. Comparisons of candidate NCC genes to ocular gene expression revealed that majority of the NCC genes are expressed in the pNC, but they are either differentially expressed or maintained during corneal development. Several genes involved in retinoic acid, transforming growth factor‐β, and Wnt signaling pathways and their modulators are also differentially expressed. We identified differentially expressed transcription factors as potential downstream candidates that may instruct expression of genes involved in establishing corneal endothelium and keratocyte identities. Conclusion: Combined, our data reveal novel changes in gene expression profiles as pNC differentiate into highly specialized corneal endothelial cells and keratocytes. These data serve as platform for further analyses of the molecular networks involved in NCC differentiation into corneal cells and provide insights into genes involved in corneal dysgenesis and adult diseases. Key Findings: RNA‐Seq profiling revealed enrichment of genes between periocular neural crest corneal endothelium, and keratocytes.The top KEGG pathways of the differentially express genes include focal adhesion, ECM‐receptor interaction, cell adhesion, melanogenesis, and MAPK signaling.Candidate neural crest genes are expressed in the periocular neural crest, but they are either differentially expressed or maintained during cornea development.Modulators of major signaling pathways associated with ocular development (retinoic acid, TGFß, and Wnt), transcription factors, and differentiation genes were differentially expressed. [ABSTRACT FROM AUTHOR]

Intravitreal injection (IVT) of antivascular endothelial growth factor (anti‐VEGF) agents is widely used for the treatment of retinal vascular diseases. Recently, the injection of anti‐VEGF agents in the ocular anterior chamber has been proposed for the treatment of neovascular glaucoma and potential side effects on the corneal structures have been investigated with contrasting results. Increasing evidence has demonstrated that VEGF inhibition is associated with cellular apoptotic changes and that this effect may be mediated by alterations in nerve growth factor (NGF) pathway. In this study, we demonstrated that anterior chamber injection (IC), but not IVT injection of two different anti‐VEGF agents, aflibercept and ranibizumab, affects rabbit corneal endothelium in terms of survival and apoptosis and is associated with changes in endothelial expression of NGF precursor (proNGF) and p75 neurotrophin receptor (p75NTR) receptor. We observed an increase in corneal endothelial cell incorporation of trypan blue and expression of cleaved‐caspase 3 (c‐Casp3), p75NTR, and RhoA after IC injection of both anti‐VEGF drugs when compared with the vehicle. Our results showed that apoptosis induction by aflibercept was more pronounced when compared with that of ranibizumab. Aflibercept also mediated a significant increase in endothelial expression of proNGF when compared with the vehicle. In line with these data, IC administration of both anti‐VEGF agents induced the activation of apoptotic signals in endothelial cells, including an increase in c‐Casp3, decrease in Bad Ser 112 phosphorylation, and unbalance of AKT phosphorylation. These results demonstrated that administration of anti‐VEGF in the anterior chamber of rabbit affects endothelial cell survival by inducing apoptosis through alteration of NGF pathway. [ABSTRACT FROM AUTHOR]

Abstract: Importance: Transient corneal endothelial changes are routinely noted on slit‐lamp examination immediately following selective laser trabeculoplasty (SLT). Background: To determine the mechanism of transient corneal endothelial changes observed following SLT. Design: University laboratory‐based observational study. Samples: Ten corneas from six human cadaveric donors. Methods: Corneas were treated with SLT, direct laser or peroxide, or used as controls. Haematoxylin and eosin staining and immunolabelling for zonula occludens‐1 (ZO‐1) and beta‐catenin were performed. Main Outcome Measures: Histological appearance; ZO‐1 and beta‐catenin immunostaining. Results: There were no differences in histological features between SLT‐treated and control corneas. Corneas treated with SLT or peroxide showed reduced and less regular ZO‐1 immunofluorescence along cell membranes compared with ZO‐1 expression in controls. These changes were generalized across the endothelium. There was no effect on the ZO‐1 immunostaining after direct laser. There was no difference in beta‐catenin immunostaining patterns between control, SLT and peroxide‐treated corneas. Conclusions and Relevance: Altered ZO‐1 immunostaining may represent disassembly of tight junctions between corneal endothelial cells. The similarity of our findings between SLT‐treated and peroxide‐treated corneas suggests that both conditions trigger changes at the level of endothelial tight junctions, perhaps triggered by liberation of free radicals as previously proposed. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To investigate the effect of the severity of keratoconus on the corneal endothelium using specular microscopy. Methods: Seven hundred and twelve eyes from the Homburg Keratoconus Center (HKC) database were included in this retrospective study. Corneal endothelium was evaluated using the Tomey EM‐3000 specular microscope. Keratoconus‐related topographic and tomographic data were obtained from Scheimpflug‐based tomography (Oculus Pentacam® HR). Eyes were classified into stages 0 (healthy) to 4 (severe keratoconus) according to the Topographic Keratoconus Classification (TKC). Subgroups were analysed based on contact lens (CL) type (none/rigid/soft). Results: The frequencies of keratoconus stages 0/1/2/3/4 according to TKC were 169/94/206/166/77. The endothelial cell density (ECD) for the endothelial cell area for TKC 0/1/2/3/4 was 2611/2624/2557/2487/2401 cells per mm² and the coefficient of variation (CV) was 40.9/40.0/41.6/46.2/49.0%, respectively. The more severe the keratoconus stage, the lower the endothelial cell count (p < 0.001) and the higher the CV (p < 0.001). No contact lens wearing was noted in 207 eyes (NoCL), rigid CL in 200 (RCL) and soft CL in 54 (SCL). CD for NoCL/RCL/SCL was 2523/2533/2644 per mm² and CV was 41.8/54.1/43.1%, respectively. A significant difference in CV was found between NoCL and RCL (p = 0.02), and no significant difference in CV was found between NoCL and SCL (p = 0.07). Endothelial cell density (ECD) did not differ significantly between NoCL and RCL or SCL. Conclusion: Endothelial cell density (ECD) decreases and CV increases significantly with increasing tomographic severity of keratoconus. In patients with RCL compared to eyes without CL wear, we found a statistically significantly higher CV in the endothelial cell size. [ABSTRACT FROM AUTHOR]

Purpose To identify and determine differences in lipid profile of aqueous humour (AH) in patients with Fuchs endothelial corneal dystrophy (FECD). Methods Lipidomic profile of eight AH samples of FECD patients and 10 control samples was analysed. Patients with previous history of anterior segment surgery, anterior segment pathology or intraocular injections were excluded. Topical ocular medications within the last 6 months were reported. Aqueous humour (AH) was obtained during the first step of Descemet membrane endothelial keratoplasty in FECD patients and during refractive lensectomy in the control group. Lipidomic ultra-performance liquid chromatography mass spectrometry was used to perform an optimal profiling of glycerolipids, sterol lipids, sphingolipids and glycerophospholipids. Metabolite extraction was accomplished by fractionating the samples into pools of species with similar physicochemical properties. Results The levels of 27 of 110 lipids change significantly in the AH of FECD eyes when compared to control samples. The concentration of most diacylglycerophosphocholines and 1-ether, 2-acylglycerophosphocholines increases in the AH of FECD eyes when compared to healthy controls. In addition, eight sphingomyelins and up to two long-chain highly unsaturated cholesteryl esters present higher levels in FECD samples when compared to controls. Conclusion The lipid composition of AH in FECD patients differs from that of healthy subjects. Those changes may reflect oxidative stress-related changes in the lipid metabolism of the corneal endothelial cells in FECD. [ABSTRACT FROM AUTHOR]

Importance This study is the first paper to establish a learning curve by a single technician. Background Preparation of pre-cut corneal endothelial grafts commenced at Lions New South Wales Eye Bank in December 2014. The primary objective of this study was to review the safety and reliability of the preparation method during the first year of production. Design This is a hospital-based, prospective case series. Participants There were 234 consecutive donor corneal lenticules. Methods Donor lenticules were prepared by a single operator using a linear cutting microkeratome. Immediately prior to cutting, central corneal thickness values were recorded. Measurements of the corneal bed were taken immediately following lenticule preparation. Outcomes were separated by blade sizes, and intended thickness was compared to actual thickness for each setting. Early specimens were compared to later ones to assess for a learning curve within the technique. Main Outcome Measure The main parameter measured is the mean difference from intended lamellar cut thickness. Results The mean final cut thickness was 122.36 ± 20.35 μm, and the mean difference from intended cut was 30.17 ± 37.45 μm. No significant difference was found between results achieved with early specimens versus those achieved with later specimens ( P = 0.425). Conclusions and Relevance Thin, reproducible endothelial grafts can routinely be produced by trained technicians at their respective eye banks without significant concerns for an extended learning curve. This service can reduce perioperative surgical complexity, required surgical paraphernalia and theatre times. The consistent preparation of single-pass, ultrathin pre-cut corneas may have additional advantages for surgeons seeking to introduce lamellar techniques. [ABSTRACT FROM AUTHOR]

Purpose To assess the impact of sequential and combined surgery [cataract surgery and 23-gauge pars plana vitrectomy ( PPV) with peeling] on corneal endothelium cell density (CED) and corneal biomechanical characteristics. Methods Phakic eyes with epiretinal membrane (ERM) were prospectively allocated to (i) cataract surgery and subsequent PPV ( CAT group), (ii) PPV and subsequent cataract surgery ( VIT group) or (iii) phacovitrectomy ( COMBI group). Eyes were examined at baseline, 1 month after each surgery, and at 3 and 12 months follow-up. Corneal endothelium cell density (CED) was assessed with non-contact specular microscopy. Pachymetry [central cornea thickness ( CCT)], keratometry and cornea volume ( CV) were measured with Pentacam Scheimpflug camera. Primary outcome was change in CED after 12 months; secondary outcomes were changes in CCT and CV after 12 months. Results Sixty-two eyes were enrolled and allocated to the three groups. The mean preoperative CED was 2776, 2794 and 2653 cells/mm2, which decreased significantly at 12 months by 15.3, 20.0 and 19.3% in the CAT, VIT and COMBI group. There was no significant difference in percentage cell loss between the groups at final follow-up. The CED decreased significantly after cataract surgery, but was unaffected by PPV. Central cornea thickness (CCT) increased by 10 μm (p = 0.005) and CV by 1.38 mm3 (2.3%, p < 0.001) in the COMBI group. There were no significant differences in CCT or CV between the groups at final follow-up. Conclusion Combined and sequential surgery in ERM leads to a small decrease in CED. Performing cataract surgery before, after or in combination with vitrectomy did not make any significant difference with respect to final CED, CCT or CV. [ABSTRACT FROM AUTHOR]

Purpose To verify that ocular surface irrigation with 0.025% povidone-iodine ( PI) or 0.0025% polyvinyl alcohol-iodine ( PAI) during cataract surgery minimizes bacterial contamination of the anterior chamber. Methods The study was a prospective, interventional case series. First, the bactericidal effect of PI or PAI against Staphylococcus aureus was evaluated in vitro. Next, in 400 eyes undergoing cataract surgery, the ocular surface was irrigated every 20 seconds during surgery with balanced salt solution ( BSS; 200 eyes) or BSS containing 0.025% PI (100 eyes) or 0.0025% PAI (100 eyes). At the completion of surgery, anterior chamber fluid was cultured bacteriologically. Visual acuity (VA) and corneal endothelial cell density were measured before and 7 days after surgery. Results A marked bactericidal effect was observed when S. aureus was directly exposed for 15 seconds to 0.01% PI or 0.001% PAI diluted in BSS. When the two solutions were stored at room temperature, bactericidal effect did not attenuate after 60 min. The bacterial detection rate at the completion of surgery was significantly reduced in 0.025% PI (0%, 0/100 eyes) or 0.0025% PAI group (0%, 0/100 eyes) compared to BSS group (5%, 10/200 eyes) (p = 0.0340). No differences in postoperative visual acuity and postoperative corneal endothelial cell density were observed between three groups. Conclusion In cataract surgery, irrigation every 20 seconds of the operative field with 0.025% PI or 0.0025% PAI, both of which contain 0.0025% available iodine concentration, achieved a very low bacterial contamination rate in the anterior chamber. [ABSTRACT FROM AUTHOR]

This study aims to systemically review the effect of laser iridotomy on the corneal endothelium. Searches were performed for studies that either compared corneal endothelial cell density/count, corneal thickness and morphology pre- and postiridotomy, or evaluated the postiridotomy development of corneal decompensation. There were 26 eligible studies. Our review shows that the effect of laser iridotomy on the corneal endothelium has been investigated with varying results. Although it has been demonstrated to be a relatively safe procedure, there is still the potential long-term risk of corneal decompensation, for which a corneal transplantation may be indicated eventually. The longest interval between laser iridotomy and corneal decompensation reported was 8 years. Mechanisms proposed for endothelial damage include direct focal injury, thermal damage, mechanical shock waves, iris pigment dispersion, transient rise in intraocular pressure, inflammation, turbulent aqueous flow, time-dependent shear stress on endothelium, chronic breakdown of blood-aqueous barrier and damage from bubbles that settled onto the endothelium. Inherent risk factors identified were iridotrabecular contact, current or prior acute angle closure, pigmented irides, small iris-to-endothelium distance, pre-existing endothelial disease and diabetes. Intervention-related risk factors include laser type, delivery and quantity. The significance of the risk factors and their direct association with the development of corneal decompensation remain to be determined. Understanding these risk factors may allow physicians to counsel their patients better. They may offer opportunities for preventive strategies, allowing us to ensure that a procedure performed to prevent disease progression and visual loss does not cause further morbidity. [ABSTRACT FROM AUTHOR]

The corneal endothelium ( CE) is a single layer of cells lining the posterior face of the cornea providing metabolic functions essential for maintenance of corneal transparency. Adult CE cells lack regenerative potential, and the number of CE cells decreases throughout life. To determine whether endogenous DNA damage contributes to the age-related spontaneous loss of CE, we characterized CE in Ercc1−/Δ mice, which have impaired capacity to repair DNA damage and age prematurely. Eyes from 4.5- to 6-month-old Ercc1−/Δ mice, age-matched wild-type ( WT) littermates, and old WT mice (24- to 34-month-old) were compared by spectral domain optical coherence tomography and corneal confocal microscopy. Histopathological changes in CE were further identified in paraffin tissue sections, whole-mount immunostaining, and scanning electron and transmission electron microscopy. The CE of old WT mice displayed polymorphism and polymegathism, polyploidy, decreased cell density, increased cell size, increases in Descemet's thickness, and the presence of posterior projections originating from the CE toward the anterior chamber, similar to changes documented for aging human corneas. Similar changes were observed in young adult Ercc1−/Δ mice CE, demonstrating spontaneous premature aging of the CE of these DNA repair-deficient mice. CD45+ immune cells were associated with the posterior surface of CE from Ercc1−/Δ mice and the tissue expressed increased IL-1α, Cxcl2, and TNFα, pro-inflammatory proteins associated with senescence-associated secretory phenotype. These data provide strong experimental evidence that DNA damage can promote aging of the CE and that Ercc1−/Δ mice offer a rapid and accurate model to study CE pathogenesis and therapy. [ABSTRACT FROM AUTHOR]

Background Whitish spots are sometimes noted in the corneal endothelium after selective laser trabeculoplasty. To evaluate the corneal endothelium after selective laser trabeculoplasty, corneal specular microscopy was performed. Design Prospective observational study in a private practice. Participants Fifteen consecutive patients with open-angle glaucoma undergoing selective laser trabeculoplasty in February 2012 had their corneal endothelium examined with specular microscopy before and after treatment. Methods Selective laser trabeculoplasty was done with 50 ± 5 shots to 180 degrees of meshwork using 0.3-0.9 mJ of power to achieve the reaction of a hint of microbubbles in 80% of laser shots. Main Outcome Measures Corneal specular microscopy photographs (0.25 × 0.54 mm) were taken prior to, immediately after and 1 month after selective laser trabeculoplasty. These photographs were assessed and graded. Results Of the 15 patients, three showed numerous, four showed few and eight showed no increase of dark spots after selective laser trabeculoplasty. All the dark spots resolved by 1 month. Conclusion The effect of selective laser trabeculoplasty on the corneal endothelium may be transient, and long-term effects are probably negligible in normal corneas. However, in compromised corneas and corneas with pigment deposits on endothelium, there may be a risk of corneal endothelial compromise, especially after repeated selective laser trabeculoplasty. Larger and longer term studies with histopathological evaluation would be useful to evaluate the effect of selective laser trabeculoplasty on normal and subnormal corneal endothelium. Until further studies are done, it would be wise to minimize the number and energy of laser shots. [ABSTRACT FROM AUTHOR]

. [ABSTRACT FROM AUTHOR]

In previous works we showed that the depolarization of the plasma membrane potential (PMP) determines a reorganization of the cytoskeleton of diverse epithelia in culture, consisting mainly of a reallocation of peripheral actin toward the cell center, ultimately provoking intercellular disruption. In view of this evidence, we explored in this study the possible effects of membrane potential hyperpolarization on the cytoskeletal organization and adherens junction (AJ) morphology and the stability of confluent bovine corneal endothelial cells in culture. For this purpose, hyperpolarization was achieved by substitution of extracellular sodium by nondiffusible cations or via the incorporation of valinomycin to the control solution. Actin compactness at the cell periphery was assessed by quantitative analysis of fluorescence microscopy images. The stability of the AJ was challenged by calcium deprivation or temperature decrease. Our results showed that plasma membrane hyperpolarization provokes a compaction of AJ-associated actin filaments toward the plasma membrane and an increase in the stability of the AJs. We also observed that the hyperpolarizing procedures determined similar modifications in the actin cytoskeleton of endothelial cells in whole bovine corneas. Together with our previous work, the results of this study contribute to the idea that modifications in the PMP of nonexcitable cells participate in cellular adaptive responses involving reorganization of cytoskeletal components. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Background: The use of dispersive ophthalmic viscosurgical devices (OVDs) has been shown to provide significant protection against air bubble damage to the corneal endothelium when compared with cohesive OVDs. We compared the corneal endothelial protective effects of a new dispersive OVD, Healon-D, with Viscoat. Methods: Healon-D and Viscoat were used in a randomized and masked fashion in the anterior chamber of 40 rabbit eyes during a procedure where ultrasound at 70% continuous energy was delivered for 2 min. Two millilitres of air bubbles were injected into the anterior chamber during the first minute of the procedure on each eye. Corneas were then stained with trypan blue and alizarin red and evaluated via light microscopy for endothelial injury. Both denuding of the endothelial layer, as well as damage to endothelial cells were quantified by using the Evaluation of Posterior Capsule Opacification digital imaging system. Results: The denuded area for eyes treated with Healon-D and Viscoat were not significantly different (medians of 0.004167and 0.003333, respectively, P = 0.8908). There was no significant difference in the area of endothelial cell damaged (medians of 0.02183 and 0.01433, respectively, P = 0.4565). When the denuded and damaged areas were calculated together, there was also no difference in the total injured area (medians of 0.05817 and 0.05821, respectively, P = 0.5740). Conclusion: The new dispersive OVD Healon-D is equally as effective as Viscoat in protecting the corneal endothelial layer from denuding and damage from air bubbles during anterior segment surgery. [ABSTRACT FROM AUTHOR]

The neuropeptide vasoactive intestinal peptide (VIP) is anti-inflammatory and protective in the immune and nervous systems, respectively. This study demonstrated in corneal endothelial (CE) cells injured by severe oxidative stress (1.4 mM H2O2) in bovine corneal organ cultures that VIP pre-treatment (0, 10−10, 10−8, and 10−6 M; 15 min), in a VIP concentration-dependent manner, switched the inflammation-causing necrosis to inflammation-neutral apoptosis (showing annexin V-binding, chromatin condensation, and DNA fragmentation) and upheld ATP levels in a VIP antagonist (SN)VIPhyb-sensitive manner, while up-regulated mRNA levels of the anti-apoptotic Bcl-2 and the differentiation marker N-cadherin in a kinase A inhibitor-sensitive manner. As a result, VIP, in a concentration-dependent and VIP antagonist-sensitive manners, promoted long-term CE cell survival. ATP levels, a determining factor in the choice of apoptosis versus necrosis, measured after VIP pre-treatment and 0.5 min post-H2O2 were 39.6 ± 3.3, 50.8 ± 6.2, 60.1 ± 4.8, and 53.6 ± 5.3 pmoles/μg protein (mean ± SEM), respectively ( p < 0.05,anova). VIP treatment alone concentration-dependently increased levels of N-cadherin ( Koh et al. 2008 ), the phosphorylated cAMP-responsive-element binding protein and Bcl-2, while10−8 M VIP, in a VIP antagonist (SN)VIPhyb-sensitive manner, increased ATP level by 38% ( p < 0.02) and decreased glycogen level by 32% ( p < 0.02). VPAC1 (not VPAC2) receptor was expressed in CE cells. Thus, CE cell VIP/VPAC1 signaling is both anti-inflammatory and protective in the corneal endothelium. [ABSTRACT FROM AUTHOR]

Purpose: Pseudophakic bullous keratopathy (PBK) is one of the main indications for corneal transplantation. Graft survival and visual outcome in this group are often poorer than for other indications. The aim of this study was to find risk factors for developing corneal oedema after cataract surgery and factors that influence the subsequent survival of the graft and the visual outcome. Methods: We carried out an observational, retrospective cohort study using data from the Swedish Cornea Transplant Register and patient medical records. A total of 273 patients whose indication for corneal transplantation was corneal oedema after cataract surgery were included in the study. Multiple logistic regression analysis and, where appropriate, univariate analyses were applied. Results: A total of 43% of the patients developed persistent corneal oedema immediately after cataract surgery, the main risk factors for which were phacoemulsification and pre-existing endothelial disease. Almost a third (32%) of the transplants for PBK failed within 2 years, for which rejection and other postoperative complications increased the risk. Half (50%) the patients had visual acuity ≤ 0.1 at 2 years after keratoplasty. Comorbidity, increasing duration of the bullous keratopathy and increasing age affected the visual outcome negatively. Conclusions: Phacoemulsification was a risk factor for immediate persistent corneal oedema after cataract surgery, although it did not increase the overall risk of developing PBK. However, transplants for immediate PBK had a better survival rate than those for later onset PBK. Shorter duration of PBK and intraocular lens exchange at the time of penetrating keratoplasty increased the likelihood of good visual acuity. [ABSTRACT FROM AUTHOR]

Purpose: The cytotoxicity of a range of commercial ophthalmic solutions in the presence and absence of preservatives was assessed in human corneal endothelial cells (HCECs), corneal epithelia and conjunctival epithelia using in vitro techniques. Methods: Cell survival was measured using the WST-1 assay for endothelial cells and the MTT assay for epithelial cells. Commercially available timolol, carteolol, cromoglicate, diclofenac, bromfenac and hyaluronic acid ophthalmic solutions were assessed for cytotoxicity in the presence and absence of preservatives. The preservatives benzalkonium, chlorobutanol and polysorbate were also tested. The survival of cells exposed to test ophthalmic solutions was expressed as a percentage of cell survival in the control solution (distilled water added to media) after 48 h exposure. Results: HCEC survival was 20–30% in ophthalmic solutions diluted 10-fold. The survival of HCEC was significantly greater in all solutions in the absence of preservative than in the presence of preservative. The survival of corneal and conjunctival epithelia was consistent with that of HCECs for all test ophthalmic solutions. The preservatives polysorbate and benzalkonium were highly cytotoxic with cell survival decreasing to 20% at the concentration estimated in commercial ophthalmic solutions. By comparison, the survival of cells exposed to chlorobutanol was 80% or greater. Conclusions: The cytotoxicity of ophthalmic solutions to HCEC, corneal epithelia and conjunctival epithelia decreased in the absence of preservative. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of Ahmed glaucoma valve (AGV) implantation on corneal endothelial cells. Methods: Ahmed glaucoma valves were implanted in 30 eyes of 30 patients with refractory glaucoma. Corneal endothelial cell density and shape was prospectively evaluated in both the subject and fellow eyes of each patient. Corneal specular microscopy was performed on the superior, superotemporal, superonasal and central corneal areas before and at 1, 6 and 12 months after surgery. Results: A statistically significant decrease in average corneal endothelial cell density was observed 12 months postoperatively in the subject eyes compared with the baseline value ( P = 0.001). No such changes were observed in the fellow eyes during follow-up period. The mean percentage decrease in corneal endothelial cell density in subject eyes was 3.5% at 1 month, 7.6% at 6 months and 10.5% at 12 months after surgery. The superotemporal area, which was closest to the tube, showed the greatest decrease in endothelial cell density at 1 year after surgery, while the central cornea showed the least decrease. In terms of endothelial cell morphology, polymegathism and pleomorphism increased in the early postoperative periods, and then gradually approached the preoperative status by 6 months after surgery. Conclusion: Corneal endothelial cell density progressively decreased after AGV implantation. These findings indicate that particular care should be taken during intraoperative and postoperative management of AGV implantation patients in order to minimize damage to the endothelium. [ABSTRACT FROM AUTHOR]

Endothelial cell function is essential to maintain corneal transparency, but unfortunately the regenerative capacity of the endothelium is limited. There are only a few reports describing the effect of age on morphologic appearance of corneal endothelial cells of dogs. Studies of normal corneal endothelial cells in humans and dogs have shown a decrease in endothelial cell density (ECD) and an increase in pleomorphism and polymegethism with advancing age. The purpose of this study was to investigate the effect of age on ECD and endothelial cell morphology in dogs. A total of 30 dogs were divided into three groups (10 dogs/group) based on age: group 1 (2–12 months old), group 2 (24–72 months old), and group 3 (84 months or older). Corneas were processed for light and scanning electron microscopy. Results showed only difference in cell density between group 1 and groups 2 and 3, showing an initial decrease in cell density as the animal matured. Whereas there was significantly greater variation in cell size within the dogs in group 3 than there was within the other two groups, suggesting that there was increased polymegethism and pleomorphism with advancing age. [ABSTRACT FROM AUTHOR]

Objective To illustrate a method of quantitative scanning electron microscopy (SEM) for the evaluation of the corneal endothelia of small animals by comparing two commonly used fixation methods. Animals studied Female New Zealand white rabbits, aged 10–12 weeks. Procedures The corneas were either dissected from the eye and placed in fixative (2% glutaraldehyde in 80 mm cacodylate, pH 7.4) or the whole eyeball immersed in fixative solution and the cornea dissected later. Lower (×200) and high magnification (×1000–5000) images were inspected for overall appearance. Magnification images (×500) were used to measure the areas of 100 cells, and cell density (CD) calculated from the average area. Results Both fixation protocols yielded an intact endothelial surface, but the dissect- then-fix protocol resulted in more creasing and distortion artifacts that were avoided with the whole-eyeball fixation. Overall, the CD values were higher if the dissect-then-fix method was used, and the uniformity of the cell mosaic was less. The median CD values for the central, mid-peripheral and peripheral regions following dissect-then-fix protocols were 7693, 7353, and 7071 cells/mm2 (average eight corneas at each location). If the whole-globe fixation was used, the median CD values were 6098, 5747, and 4785 cells/mm2. Conclusion Cell density values in SEM can be very different according to the fixation method used. A distinct regional difference in CD was evident, which was more pronounced if the cornea was fixed prior to being dissected from the eye. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the endothelial surface morphology and to perform morphometric analysis of the corneal endothelial cells of Yacare caiman (Caiman yacare) using scanning electron microscopy. Morphometric analysis with regard to polygonality, mean cell area, cell density and coefficient of variation of mean cell area was performed. Cell areas were measured using image analysis software. The normal corneal endothelium of Yacare caiman consisted of polygonal cells of uniform size and shape with interdigitations of the cell borders. Microvilli appeared as protrusions on the cellular surface. The average cell area was 270 ± 24 µm² and the endothelial cell density was 3704 ± 324 cells/mm². The coefficient of variation of cell area was 0.22. This study demonstrates that the Yacare caiman corneal endothelium is similar to those described in other vertebrates. [ABSTRACT FROM AUTHOR]

Purpose: To study the corneal endothelium and pachy­metry in eyes with different subtypes of primary angle closure glaucoma (PACG), as compared to controls. Methods: A cross-sectional study was conducted on 30 consecutive patients in each subtype of PACG, subacute, acute and chronic, and 30 age and refraction matched controls. The parameters recorded included gonioscopy, optic disc evaluation, applanation tonometry, specular microscopy and central ultrasonic pachymetry. Results: The mean endothelial cell counts in the four groups were as follows: subacute PACG 2396 ± 271 cells/mm2, acute PACG 1597 ± 653 cells/mm2, chronic PACG 2229 ± 655 cells/mm2 and controls 2461 ± 321 cells/mm2. The mean endothelial cell count in the fellow eyes of subacute PACG, acute PACG and chronic PACG patients was 2294 ± 305 cells/mm2, 2388 ± 226 cells/mm2 and 2108 ± 203 cells/mm2, respectively (NS). The acute PACG patients had significantly lower endothelial cell counts ( P < 0.001) as compared to the other three groups. Eyes in which the acute attack of angle closure persisted for less than 72 h had a mean endothelial cell count of 2016 ± 306 cells/mm2, as compared to 759 ± 94.4 cells/mm2 in eyes with an attack lasting for 72 h or more ( P < 0.001). The endothelial count was also significantly lower in eyes with chronic PACG as compared to control eyes ( P < 0.001). There was increased pleomorphism and polymegathism of the corneal endothelial cells seen in eyes with resolved acute and chronic PACG. The mean central corneal thickness was 531.4 ± 25.3 µm in eyes with subacute PACG, 567.9 ± 37.3 µm in eyes with acute PACG, 526.4 ± 31.9 µm in eyes with chronic PACG and 525 ± 12.6 µm in control eyes. The acute PACG eyes had a significantly higher corneal thickness ( P < 0.001) when compared to all the other groups. Conclusion: There is a significant decrease in the corneal endothelial cell density in eyes that have had an acute attack of angle closure glaucoma and in eyes with chronic PACG. The endothelial cell population in eyes with sub­acute PACG and in the fellow eyes of all subtypes of PACG is not significantly different from the normal population. [ABSTRACT FROM AUTHOR]

Abstract Objective To investigate the potential damage to the canine corneal endothelium following transcorneal iridal laser photocoagulation using a semiconductor diode laser. Animals studied Sixteen young mongrel dogs. Procedures Baseline corneal endothelial cell counts and corneal thickness were measured in the central and temporal quadrants using a noncontact specular microscope under general anesthesia. Transcorneal iridal photocoagulation was applied using a semiconductor diode laser in a continuous mode with the use of an operating microscope. Fifteen dogs were treated, and the sixteenth dog served as a control. Fifteen different treatment combinations were randomly assigned to the 30 eyes; the fellow eye was treated differently. Three treatment factors were investigated: (1) laser energy intensity, (2) target tissue to endothelial distance, and (3) laser application duration. After 3 weeks the dogs were euthanized, specular microscopy was repeated, and the cornea was examined by scanning electron microscopy. Results Dyscoria and focal iris darkening were noted in all eyes immediately following laser treatment. Focal corneal edema (n = 2) and an incipient anterior capsular cataract (n = 1) were also noted. Baseline mean corneal endothelial cell densities were 2530 cells/mm[sup 2] centrally and 2607 cells/mm[sup 2] temporally. Postlaser corneal endothelial cell densities were 2499 cells/mm[sup 2] centrally and 2523 cells/mm[sup 2] temporally. Mean prelaser corneal thickness measurements were 0.555 mm centrally and 0.549 mm temporally. Postlaser corneal thickness measurements were 0.580 mm centrally and 0.554 mm temporally. Statistical analyzes revealed no significant changes in endothelial cell densities (P > 0.05) or corneal thickness (P > 0.05) induced by any treatment combination. Aside from tissue handling and processing artifacts, scanning electron microscopy revealed no endothelial cell damage. Conclusions Our study demonstrated by specular and scanning electron microscopy that diode laser iridal photocoagulation had no significant effect on the canine corneal endothelium within the parameters described. However, one must take into consideration the young age of the dogs and the potential for corneal endothelial cell regeneration in young dogs, and the relatively short period of postoperative study. [ABSTRACT FROM AUTHOR]

ABSTRACTPurpose: Modification of a donor cornea by gene therapy has potential to modulate irreversible rejection, the major cause of corneal graft failure. The sheep is a useful model for the human in this respect, as ovine endothelial cells are amitotic. The aim of the study was to investigate the ability of various non-viral and viral agents to transfer a reporter gene to ovine corneal endothelium. Methods: The non-viral agents Transfectin-10, Transfectin-20, Transfectin-50, SuperFect, Effectene and CLONfectin were used to deliver the reporter gene, Escherichia coli lacZ, to ovine corneal endothelium in vitro. A Herpes simplex virus-1 and an adenoviral vector each encoding E. coli lacZ were similarly tested. Infected corneas were organ-cultured for up to 7 days in vitro to allow transfection efficiency, duration of gene expression and toxicity attributable to each vector to be compared. Results: Scattered single or clusters of endothelial cells expressing the reporter gene were observed after transfection with CLONfectin, Transfectin-10, Transfectin-20 and Transfectin-50. SuperFect and Effectene were virtually in-effective. At best, the absolute number of infected cells per endothelial monolayer after 3 or 7 days of organ culture was estimated as < 0.01%. The Herpes simplex virus-1 vector also failed to transduce ovine corneal endothelium efficiently. In contrast, transfection rates of up to 70% of endothelial cells were observed with the adenoviral vector. Conclusion: Non-viral vectors and Herpes simplex virus-1 are unlikely to be suitable for gene therapy of corneal endothelium, because the efficiency of transfection is low compared with the rates achieved with adenoviral vectors. [ABSTRACT FROM AUTHOR]

ABSTRACTPurpose: To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. Methods: Lid suture was performed on one eye of 1-day-old cockerels. Five chickens were killed at 1 week, and four chickens killed at each of 3 weeks, 6 weeks, and 10 weeks postnatal. The endothelial morphology was obtained by flat mounting the endothelial surface and the subsequent digitisation. Comparisons were undertaken between the control unsutured eye and the lid-sutured eye endothelium, and between the central endothelial areas compared to the peripheral endothelial areas in both the myopic and the normal corneas. Calculation of the contribution to the endothelial change by hypertrophy and mitosis were calculated using Bahn’s formula. Results: Total endothelial surface area increased significantly over time in the myopic model compared to control eyes but the mean cell area of endothelial cells remained the same for both the enlarged myopic endothelial surface area and in the normal controls. Sampling from the central and the peripheral corneal endothelial surface also disclosed no difference. The mean cell area did increase steadily with age but was the same for both normal and myopic corneas. Conclusions: It would appear that there are equal contributions from hypertrophy and mitosis in the myopic group and the normal corneal group with a slightly increasing trend towards mitotic activity in the myopic corneal endothelial layer. [ABSTRACT FROM AUTHOR]

Corneal oedema and bullous keratopathy may occur following intraocular surgery or arise spontaneously in nonguttate eyes. In some patients the fellow eye shows a relatively normal endothelial cell count with abnormal pleomorphism and polymegathism of the endothelial cells, while in others it shows a markedly lowered endothelial cell count with no evidence of corneal guttae. A survey of 17 such patients suggested the following classification. 1. Nonguttate corneal endothelial dystrophy with irregular endothelial cell morphology but a relatively normal endothelial cell count occurring following surgery (eight patients) or spontaneously (four patients). 2. Nonguttate corneal endothelial dystrophy with grossly reduced endothelial cell count occurring spontaneously (two patients). Three additional post-surgical patients showed a relatively normal endothelial cell count and only mild changes in the morphology of the corneal endothelium. These findings support the presence of a nonguttate corneal endothelial dystrophy in both the spontaneous and some of the post-surgical cases. [ABSTRACT FROM AUTHOR]

The corneal endothelium was assessed following penetrating keratoplasty in a series of 50 patients and eight illustrative cases are described. Assessment disclosed a wide variation in the endothelial cell count and morphology following keratoplasty. In some patients the endothelial cell count was so low and the morphology so abnormal that long-term survival of the graft was doubtful. In cases with such a low count it is very doubtful, whether the graft will survive a secondary procedure such as cataract extraction or, intraocular lens implantation. Some donor material may carry corneal guttae and the use of such material should be avoided. If the material is good it will withstand inflammatory episodes including graft rejection if treatment is prompt and appropriate. Satisfactory material may be obtained from elderly donors while a young donor does not guarantee suitable material. It is desirable to assess the corneal endothelium of donor material carefully before use. [ABSTRACT FROM AUTHOR]

A series of patients is presented showing the widely variable clinical behaviour of different groups of patients who share the common features of cyclitic glaucoma. These cyclitic glaucomas may be classified: 1. Glaucomatocyclitic crises: unilateral or bilateral. This condition presents acutely, almost always in males with a strong tendency to spontaneous resolution but a liability to subsequent recurrence. Some cases are slow to resolve and may recur frequently. 2. Heterochromic cyclitis: glaucoma infrequently complicates heterochromic cyclitis and then with only a mild rise in intraocular pressure (IOP). 3. Chronic cyclitis: unilateral or bilateral. This is more common in females often presenting with a high rise in IOP which may be difficult to control medically. An insidious form of chronic cyclitis occurs in middle-aged, blue-eyed females, often with sarcoid, and is likely to progress to profound visual loss if unrecognised. [ABSTRACT FROM AUTHOR]

The ability of the cornea to maintain its transparency after surgery depends primarily upon the integrity of the corneal endothelium and in corneal grafting this is important for both donor and recipient eyes. The corneal endothelium may be significantly affected in various conditions of the anterior segment, especially if these exist over a considerable period of time. These conditions include superficial keratopathy, long-term contact lens wear, cornea guttata and low-grade anterior uveitis, especially chronic cyclitis which may be almost imperceptible clinically. The suitability of such corneas for use as donor material as well as the response of the eyes to anterior segment surgery can be assessed by specular microscopy and this may become even more important in the future as long-term contact lens wearers become more numerous in the community. [ABSTRACT FROM AUTHOR]

The use of specular microscopy is not confined to the corneal endothelial mosaic, but may be used at any level through the corneal stroma to the posterior endothelial surface. In the stroma the not very dense, irregularly rounded deposits of corneal dystrophies may be differentiated from the dense, geometric shapes of crystalline deposits. At the level of Descemet's membrane the fine parallel lines of tears in Descemet's are distinct from the multiple fine vertical deep stromal lines seen in advanced keratoconus. At the level of the endothelial mosaic the cells may be counted and their morphology examined, while blebs may also be seen in a wide variety of pathological conditions including superficial keratopathies, contact lens wearers, deep keratopathies, anterior uveitis and contusion injury. These blebs vary in size in different conditions and are often transient. They must be distinguished from guttae which are permanent and although an occasional finding in normal corneas are a constant feature of cornea gutatta and Fuchs' dystrophy. On the posterior endothelial surface the relief mode enables the examination of numerous deposits including red blood cells, white blood cells, keratitic precipitates, pigment granules and pseudoexfoliative KP. The morphology of these various findings is discussed. [ABSTRACT FROM AUTHOR]

Changes on corneal endothelial specular microscopy were compared in 14 patients with cornea guttata, 4 patients with Fuchs' corneal dystrophy and 19 patients with various forms of bullous keratopathy. The patients with cornea guttata showed well marked guttae 1 to 6 endothelial cells in diameter in the endothelial mosaic and in the relief mode while the endothelial mosaic was usually otherwise within normal limits. In 2 patients with Fuchs' dystrophy the endothelium could be examined, showing gross guttae but a few areas of relatively normal endothelial cells. The unaffected eye of 3 other patients snowed findings similar to cornea guttata, but with some reduction in endothelial cell count in 2 patients. The patients with bullous keratopathy fell into 2 groups, one with gross reduction in cell count in a markedly abnormal endothelial cell mosaic, the other a mixed group with moderate reduction in cell count and numerous guttae. Some miscellaneous cases included one of aphakic peripheral bullous keratopathy, one associated with cyclitis and aphakia and 2 with idiopathic non-surgical bullous keratopathy. We believe the corneal endothelium is not grossly abnormal away from the guttae in Fuchs' dystrophy, but the gross guttata formation determines the endothelial dysfunction. [ABSTRACT FROM AUTHOR]

In order to differentiate clearly red blood cells and their relationship to the corneal endothelium, specular microscopy was performed in patients with hyphaema due to contusion injury. This enabled the clear identification of red blood cells as rounded, umbilicated or flattened spheroidal structures depending on whether they were seen side on or end on. They were seen best in the relief mode lying on the posterior endothelial surface and not infiltrating the corneal endothelium. It also disclosed the presence of subendohelial blebs one to three cells in diameter seen at the level of the corneal mosaic and not in the relief mode. These are probably due to mild oedema following the contusion injury and were distinct from the red blood cells. The corneal endothelial cell count and morphology were similar to that in the other eye when the changes resolved a week or so after the injury. [ABSTRACT FROM AUTHOR]

Examination of the corneal mosaic by the direct mode of specular microscopy and of its posterior surface by the relief mode in three cases of localized keratitis with adjacent clear cornea has enabled us to identify small round white cells. Comparison with the morphology of red blood cells seen in hyphaema indicates that these small round cells are probably lymphocytes since they are fairly uniform in size, spherical but not flattened spheroids and about the same size as or a little larger than red blood cells. These cells are present on the posterior surface of the corneal endothelium but could not be seen infiltrating beneath or between the endothelial cells. They were quite distinct from larger, numerous rounded blebs two to four endothelial cells in diameter tying beneath the endothelium which have previously been described. [ABSTRACT FROM AUTHOR]

In this study, vitamin E (alpha-tocopherol), a powerful antioxidant, is shown to double the survival time of isolated perfused rabbit corneal endothelium. The results are discussed and evidence concerning vitamin E in ocular tissue function is reviewed. [ABSTRACT FROM AUTHOR]

Recent work has shown changes in the corneal endothelium accompanying corneal epithelial disease and anterior uveitis. It is important to differentiate these acute changes from other changes such as guttatae or corneal pigment deposition and to assess the magnitude of their effect upon the corneal endothelium. We have used specular microscopy to study changes in the corneal endothelium and Descemet's membrane and to study deposits on the back of the corneal endothelium and correlate them with changes in the endothelium by the use of conventional specular microscopy and by relief images which give a three dimensional view of the area concerned. This has particularly been applied to the conditions of superficial punctate keratopathy, keratoconjunctivitis sicca, corneal abrasions and exposure keratopathy, iritis and cyclitis, pseudoexfoliation of the lens capsule, anterior sement pigment dispersal syndrome, bullous keratopathy as well as corneal guttatae and pigment granuis on the posterior cornea. freendothelial lesions have been distinguished from endothelial and retrocorneal lesions by this technique aiding elucidation of the state of the endothelium. The changes which we noted occurred either at the level of Descemet's membrane (including formation of small rounded dark blebs less than one cell in diameter, larger blebs one to three cells in diameter, and guttatae, usually larger than the foregoing and sometimes very numerous), or at the level of the posterior endothelial surface (including small shiny nodular deposits, often numerous. due to pigment granules, and keratitic precipitates and inflammatory debris, the former usually large and the latter smaller, more irregular and somethimes very numeroug The differentiation and assessment of these various changes are discussed. [ABSTRACT FROM AUTHOR]

Fluorescein angiography of the iris vasculature and specular microscopy of the corneal endothelium were used to examine two important anterior chamber tissues in cases of heterochromic cyclitis, classical chronic cyclitis and some cases of iridocyclitis. The 13 cases of heterochromic cyclitis and eight cases of classical chronic cyclitis all showed vascular hypoperfusion of the iris, except for two young females with heterochromia. In these cyclitis eyes there was pupillary leakage of dye and all but one young female with heterochromia showed evidence of microneovascularization of the iris. Most patients showed evidence of abnormalities of the corneal endothelium, but this was most marked in elderly patients with heterochromic cychtis, probably due to the long duration of the condition. Six of the patients with chronic cyclitis had bilateral disease and five of these were elderly women with glaucoma and grey irides, the group being distinct enough to form a discrete clinical entity. Seventeen of the patients with chronic cyclitis were females with grey irides suggesting that this type of patient is more susceptible to cyclitis. Patients with acute iridocyclitis showed little abnormality on fluorescein angiography, while those with recurrent or chronic disease showed vascular hypoperfusion and microneovascularization suggesting that these changes in the iris contribute to the chronicity of the condition. It is suggested that hypoperfusion and microneovascularization of the iris and abnormal permeability are important factors in the production of chronic cyclitis, and that the integrity of the corneal endothelium is affected by these changes if they operate over a long period of time. [ABSTRACT FROM AUTHOR]

A series of five cases is described in which superficial punctate keratopathy was associated with endothelial cell changes. The most striking change was the presence of dark areas or blebs, usually two to four cell diameters in extent. There was also distortion and crumpling of the corneal endothelium, mild pleomorphism and polymegathism of the endothelial cells, with a reduced cell count in some cases. These blebs have previously been reported in hard and soft contact lens wearers and are due to intercellular oedema with separation of endothelial cells from Descemet's membrane. Anoxia and interference with osmosis have been proposed as possible mechanisms for the production of these blebs, but our cases demonstrate that fine disruption of the corneal epithelium can affect the integrity of the corneal endothelium and may lead to significant damage over a Ion period of time. [ABSTRACT FROM AUTHOR]

A clinical study of posterior corneal rings in human eyes was undertaken using the Pocklington (Keeler-Konan) contact wide field specular microscope designed by Sherrard. The method used to reproduce identical posterior corneal rings in the same human cornea, in vivo, using the contact wide field specular microscope camera, without the aid of a contact lens, is described. The technique enables the clinician to relocate and evaluate a selected area of human endothelial cells in the same eye. [ABSTRACT FROM AUTHOR]

Background: Recently, many patients with corneal blindness caused by endothelial dysfunction have no opportunity to receive keratoplasty therapy because of the extremely limited number of donor corneas. Corneal tissue engineering opens a new path for in vitro reconstruction of tissue‐engineered HCE which will cure the corneal endotheliopathy by clinical corneal transplantation. In this study, we construct a human corneal endothelium (HCE) equivalent with non‐transfected monoclonal HCE (mcHCE) cells and modified denuded amniotic membrane (mdAM), and evaluate its functions in monkey models. Methods: Tissue‐engineered HCE (TE‐HCE) was constructed by culturing DiI‐labeled mcHCE cells on mdAMs in 20% fetal bovine serum‐containing DMEM/Ham's Nutrient Mixture F12 (1:1) medium and 5% CO2 at 37°C on a 24‐well culture plate. The constructed TE‐HCE was transplanted into monkey corneas via penetrating keratoplasty with Descemet's membrane and endothelium stripped. The corneal transparency, thickness, and intraocular pressure were monitored in vivo, and the corneal morphology and histological structure were examined ex vivo 181 days after surgery. Results: The constructed TE‐HCE, with an average density of 3602.22 ± 45.22 cells/mm2, mimicked its natural counterpart both in morphology and histological structure. In vivo, corneal transparency was maintained, and the corneal thickness gradually decreased to 567.33 ± 72.77 μm at day 181 after TE‐HCE transplanted into monkey eyes, while intense corneal edema and turbid were found in mdAM‐transplanted eyes with their corneal thicknesses maintained over 1000 μm during the monitoring period. Ex vivo, a monolayer of corneal endothelium, consisting of mcHCE cells at a density of 2795.65 ± 156.83 cells/mm2, was reconstructed in transplanted monkey eyes. The cells in the transplanted area had the hexagonal or polygonal morphology and normal ultrastructure, and established plenty of cell‐cell and cell‐stromal matrix junctions. Besides, huge membrane‐bounded flat stacks with electric dense inclusions were found in mcHCE cells beneath the plasma membrane at the stromal side. Conclusions: The constructed TE‐HCE has normal histological property and functions well in monkey models. The TE‐HCE could be used as a promising HCE equivalent in therapy of corneal endothelium dysfunction and corneal regenerative medicine. [ABSTRACT FROM AUTHOR]