Corneal Endothelial Surface Research Articles

Noninvasive Diagnosis of Viral Keratouveitis with Retro-corneal Endothelial Plaques: A Case Series

ABSTRACT Purpose The aim of this study was to evaluate the noninvasive diagnostic methods in managing the herpetic keratouveitis with retro-corneal endothelial plaques. Methods 12 patients suspected to have unilateral herpetic keratouveitis with retro-corneal endothelial plaques were included. Slit lamp photos, AS-OCT, IVCM and corneal scraping culture were taken in all cases to help diagnosing and managing the disease. All patients received systemic and topical anti-viral treatment immediately and combined with topical steroids three days later. Results Corneal scraping culture ruled out bacterial and fungal infection. AS-OCT showed that the boundaries between the corneal endothelial surface were clear in all patients. Corneal endothelial density and subbasal nerve plexus significantly decreased in all patients. Endothelial plaques reduced or disappeared in all patients with the treatment. Conclusions Retro-corneal endothelial plaques and hypopyon are associated clinical manifestations of viral keratouveitis. AS-OCT and IVCM enhanced early detection and assessment during the follow-ups of the disease.

Correlation between Corneal Endothelial Cell Density and Central Ocular Surface Temperature in Normal and Keratoconus Eyes

ABSTRACT Purpose In keratoconus (KC), an increase of the corneal back surface area may result in endothelial cell density (ECD) decrease and an increase of the corneal front surface area in ocular surface temperature (OST) decrease due to increased heat dissipation. Along with these hypotheses, we aimed to analyse the correlation between ECD and central corneal OST in patients with KC and healthy controls. Patients and methods A total of 154 eyes with KC (mean age 36.1 ± 12.5 years) and 92 healthy eyes (mean age 36.4 ± 12.8 years) were examined. Corneal front and back surface area at the central 5 mm corneal diameter (FSA and BSA) were calculated based on Pentacam measurement data: FSA or BSA = 2×3.14×R(R-√R2-D/2)2, where R referred to corneal front or back surface radius of curvature and D to the corneal front or back surface diameter (5 mm for the present study), respectively. ECD was determined by specular microscopy (EM-3000) and central corneal OST by thermography (TG-1000). Results ECD was significantly lower in KC (2498 ± 356/mm2) patients than in controls (2638 ± 294/mm2; p < .001). FSA (20.35 ± 0.26 mm2 vs. 20.17 ± 0.03 mm2) and BSA (20.84 ± 0.58 mm2 vs. 20.45 ± 0.08 mm2) were significantly higher in KC patients than in controls (p = .001; p < .001), but the average central corneal OST did not differ significantly between both groups (34.2 ± 0.6°C vs.34.3 ± 0.7°C; p = .62). OST at the corneal centre correlated weakly, positively with ECD (r = 0.2; p < .05), but OST did not correlate with FSA (r = 0.045) or BSA (r = 0.064). Conclusions Endothelial cell density seems to have a mild impact on central ocular surface temperature in keratoconus and normal subjects. This effect is not correlated to the corneal front or back surface area.

Evaluation and grading of Kayser–Fleischer ring in Wilson disease by Scheimpflug camera

Evaluation the anterior segment parameters of Wilson disease patients with Kayser-Fleischer ring, the diagnostic power of Scheimpflug imaging for Kayser-Fleischer ring and suggest a scoring system. A total of 44 eyes of 22 Wilson disease patients with Kayser-Fleischer ring and 40 right eyes of 40 healthy age matched subjects were enrolled to the study. Serum ceruloplasmin and urine copper/24 hours levels were recorded. Anterior segment parameters including steep and flat keratometry, corneal thickness at central, 2, 4, 6, 8 and 10 mm, anterior chamber angle width, volume and depth, corneal volume, pupillary diameter were evaluated by Scheimpflug imaging. Images of cornea were scored according to Kayser-Fleischer ring size. Serum ceruloplasmin level was below 10 mg/dL in 17 patients and was 12, 18.5, 20, 22, 37 mg/dl in the remaining five patients. Urinary copper/24 hours was 249.55 ± 304.14 (23-1050) µg/day. Central corneal thickness and corneal thickness at 2 mm were statistically different (p values 0.02, 0.04, respectively). Scheimpflug images apparently showed Kayser-Fleischer ring as a hyper-reflective band at the corneal endothelial surface. Kayser-Fleischer ring in 24 eyes was grade 1, 16 eyes were grade 2 and 4 eyes were grade 3. Scheimpflug imaging seems to be a helpful diagnostic tool for detecting and grading the Kayser-Fleischer ring. Corneal thickness in Wilson disease patients with Kayser-Fleischer ring tends to be higher, so that the possible affection in corneal thickness should be kept in mind for clinical evaluation of these patients.

Clinical observation of ocular injury caused by chestnut burr

Objective: To analyze the clinical characteristics and treatment of ocular injury caused by chestnut burr. Methods: Retrospective case series study. Data of 48 patients (48 eyes) with ocular injuries caused by chestnut burrs hospitalized in Qingdao Eye Hospital were collected from January 2013 to March 2019. All patients were followed up for at least 3 months. The time of seeking medical advice, lesion region, and characteristics and treatment methods were analyzed. Results: There were 48 patients, including 33 males and 15 females, aged 19 to 74 years [mean, (56±10) years]. The time of injury was late September (25 cases) and early October (23 cases). The shortest time to visit our hospital was 3 hours after injury, and the longest was 8 months after injury. There were 13 cases (27.1%, 13/48) with corneal and/or scleral foreign bodies. All patients were treated with corneal or scleral foreign body extraction. Twenty-four patients (50.0%, 24/48) developed fungal keratitis. Among them, 18 patients had a corneal ulcer, and the infection involved the superficial or full-thickness corneal layer. Six patients had no corneal ulcer, and the infection involved the deep stroma and corneal endothelial surface. The positive rate of fungal examination by confocal microscopy was 87.5% (21/24). Antifungal drugs (2 cases), corneal debridement (5 cases), conjunctival flap covering (2 cases), corneal stroma injection (1 case), and penetrating keratoplasty(14 cases) were given according to the depth of fungal infection. Most of the pathogens were Alternaria spp. Eleven patients (22.9%, 11/48) with necrotizing scleritis were treated with exploration of the sclera. Three patients had scleral foreign body residues on ultrasound biomicroscopy examination, which were removed by operation. Four patients were found to have fungi at the necrotic site of the sclera. Conclusions: The main types of ocular injuries caused by chestnut burrs are corneal and/or scleral foreign bodies, fungal keratitis, and necrotizing scleritis. Chestnut burr foreign bodies should be removed as soon as possible. In the case of fungal keratitis, a drug or surgical intervention should be carried out as early as possible. Necrotizing scleritis is often induced by long-term foreign body retention. Scleral incision and exploration is an effective form of treatment. (Chin J Ophthalmol, 2020, 56: 370-375).

Evaluation of equine corneal endothelium after exposure to 0.05% brilliant blue - an in vitro study

ABSTRACT The aim of this study was to evaluate the immediate effects of 0.05% brilliant blue on corneal endothelium of horses. Thirty-eight corneas of 19 horses, male or female, of different ages were studied. Corneas were randomly divided into two groups. Group 1: Corneal endothelium was covered with 0.3mL of brilliant blue 0.05% for 60 seconds followed by rinsing with a balanced salt solution. Group 2: Corneal endothelium was covered with BSS for 60 seconds. The corneas were excised with an 8mm trephine and prepared to analyze posterior endothelial surface using a light microscope (24 corneas) and a scanning electron microscope (14 corneas). The equine posterior corneal endothelium surface observed by optical microscopy and scanning electron microscopy revealed a continuous layer of polygonal cells of uniform size and shape in both the control and treatment groups. Due to non-normal residuals at ANOVA mean comparison, a generalized linear model was utilized at 5% level of significance. The chi-square test stated that treatment and control group were not different statistically. The 0.05% brilliant blue did not cause damage to equine corneal endothelium.

A Rabbit Corneal Endothelial Dysfunction Model Using Endothelial-Mesenchymal Transformed Cells

Unlike humans, rabbit corneal endothelial wounds are known to spontaneously heal. The current study was aimed to develop a new rabbit bullous keratopathy model using corneal endothelial cells that were induced to undergo endothelial-mesenchymal transformation (EMT). EMT was induced in rabbit corneal endothelial cells (RCECs) by culturing with TGFβ and basic FGF Supplemented Medium. The corneal endothelia in recipient rabbits were mechanically scraped from the corneal endothelial surface inside an 8 mm mark. Then, a suspension of EMT-induced RCECs (EMT-RCECs) was injected into the anterior chamber. Eyes injected with freshly isolated RCECs (Fresh RCECs group) and eyes that were scraped without injection of cells (Scrape group) were used as controls. Immediately following operation, subepithelial and stromal edema was observed with increased central corneal thickness and corneal opacity in all groups. In the EMT-RCECs group, bullous keratopathy persisted for 42 days up to the end of the study. In the Fresh-RCECs and Scrape groups, corneal transparency and thickness recovered by 7 days after treatment and was maintained up to 42 days. The activated fibroblast marker, α-SMA, was observed spanning from corneal endothelium to corneal stroma in the EMT-RCECs group. Interestingly, α-SMA was upregulated in the Scrape-group as well. In all groups, there was no damage to other intraocular structures, and intraocular pressure was normal throughout the observation period. Transplanting a fresh donor cornea effectively treated corneal edema due to bullous keratopathy. This model is a promising tool for pre-clinical trials in the development of new therapies against corneal endothelial dysfunction.

Ultrastructure observation of rhesus bone marrow mesenchymal stem cell after transplantation of cornea

Background The quest to look for seed cells is a hot spot of cornea transplant research in solving the problem of the lack of donor. Bone marrow mesenchymal stem cells(BMSCs) have been successfully induced into retinal ganglion cells(RGCs) in vivo,but the successful induction of BMSCs into corneal endothelial cells has not been reported.Objective This experiment was to study the transplantation of BMSCs on corneal endothelial surface using the splitting Descemet's membrane. Methods Four healthy adult rhesus monkeys were divided into the experimental group ( 3 monkeys) and control group ( 1 monkey). Mesenchymal stem cells (MSCs) were isolated from bone marrow by density gradient centrifugation combined with adhering means. The cultured cells were identified by flow cytometry and its ability to differentiate was determined by allowing them to differentiate into adipocytes in vitro and labeled by 5-bromodeoxyuridine ( BrdU ) for subsequent identification. Corneal grafts of 7 mm in size with tearing of the Descemet' s membrane were prepared in the experimental group and control group. After labeling by 5-bromodeoxyuridine( BrdU ) ,cultured cells were transplanted onto the endothelial surface of cornea grafts in the experimental group, but no cultured cells were seeded in the graft of the control group. The corneal grafts were then sutured in situ, and were removed 1,2 or 3 months after operation to examine the distribution and connection between transplanted cells and their morphologic changes under the electron microscope. Results High purity MSCs were harvested by density gradient centrifugation combined with adhering method. Cultured cells reached confluency after 12 to 16 days, presenting with a spindle shape and parallel or swirling arrangement. Flow cytometry analysis showed that 94.26％ of cells were positive for CD29,7. 51％ for CD34 and 4. 02％ for CD45. Larger nuclei filled with plastosomes, golgiosomes and rough endoplasmic reticula were found on the graft under the transmission electron microscope( TEM ). After 3 weeks, MSCs were differentiated into adipocytes where Oil Red O staining resulted in an orange-red staining in the cytoplasm and blue staining in the nuclei. The transplanted cells attached loosely on the endothelial surface of the corneal graft and came in contact with each other in one month. The shape of the cells appeared as spindle-shaped and polygonal after 2 months and became tightly packed after 3 months. The positive cells retained the BrdU label and presented with brown nuclei. No endothelia cells grew in the cornea graft in the control group, with an absence of BrdU labeling. Conclusions Mesenchymal stem cells can be transplanted onto the corneal endothelial surface successfully and form a monolayer using the centrifugation method, and present with good survival and proliferation ability. Key words: Bone marrow mesenchymal stem cell; Corneal transplantation; Rhesus; Ultramicrostructure

Knockdown of NBCe1 In Vivo Compromises the Corneal Endothelial Pump

To evaluate the role of the sodium bicarbonate cotransporter (NBCe1) as a component of the corneal endothelial pump in the in vivo rabbit eye. Lentiviruses with NBCe1 shRNA and GFP expression cassettes were injected intracamerally. Knockdown efficacy was determined 1 week to 4 weeks later by immunofluorescence, Western blot analysis, and PCR. Functional effects were monitored by corneal thickness (CT) and brinzolamide sensitivity. Within 24 hours there was a modest anterior chamber inflammation that resolved within 48 hours. At 4 × 10(6) IFU, more than 95% of the corneal endothelial surface showed GFP fluorescence above background within 7 days. At 14 to 21 days, signs of anterior chamber inflammation reemerged, and endothelial cell GFP fluorescence disappeared within 40 days after injection. The second phase of inflammation could be avoided by using GFP-less viruses. There was no significant difference in CT between scrambled sequence and NBCe1 shRNA-injected eyes over 3 weeks. Two drops of 1% brinzolamide produced 7.85% ± 3.3% corneal swelling within 5 hours of topical instillation. However, in corneas showing more than 25% NBCe1 knockdown (30 of 42 rabbits; 59% ± 15% knockdown), corneal swelling was significantly higher (10.1% ± 2.9%) relative to control eyes. FIV-based lentiviral vectors can transfect CE with shRNA in rabbits. The response to GFP is consistent, with previous studies showing the production of anti-GFP antibodies. Partial knockdown of NBCe1 did not affect baseline CT, which is consistent with the corneal endothelium having a substantial functional reserve. Provocative testing using, brinzolamide, however, revealed an underlying deficiency, confirming the importance of NBCe1 bicarbonate transport and demonstrating the concerted action between NBCe1 and carbonic anhydrases.

Aquaporins in endothelia

Aquaporin-1 (AQP1) water channels are expressed widely in microvascular endothelia outside of the central nervous system, including renal vasa recta and tumor microvessels, as well as in non-vascular endothelia in pleura, peritoneum, cornea, and lymphatics. In kidney, AQP1-facilitated water transport in outer medullary descending vasa recta is likely an important component of the urinary concentrating mechanism. However, in most vascular endothelia outside of kidney, it remains uncertain whether AQP1 expression and high water permeability are physiologically important. AQP1 in non-vascular endothelia at the inner corneal surface is involved in the maintenance of corneal transparency. Recently, a new role of AQP1 in endothelial cell migration was discovered in analyzing the cause of defective tumor angiogenesis in AQP1-deficient mice. AQP1 facilitates endothelial cell migration by a mechanism that may involve facilitated water transport across cell protrusions (lamellipodia). AQP1 inhibitors may thus have aquaretic and antiangiogenic activity.

Induction of Replication in Human Corneal Endothelial Cells by E2F2 Transcription Factor cDNA Transfer

Corneal endothelial cells in humans do not replicate to any meaningful extent. Diminishing density of the cell monolayer with age and in the disease states is a major cause of loss of corneal transparency. This study was conducted to test the hypothesis that overexpression of the transcription factor E2F2 results in replication in nonproliferating human corneal endothelial cells. Whole human corneas were incubated for 2 hours in a solution of recombinant E1(-)/E3(-) adenovirus incorporating cDNA encoding E2F2 and green fluorescent protein (GFP) under control of a bidirectional promoter and subsequently maintained in ex vivo culture. Control specimens were incubated with an identical virus bearing the GFP sequence only, or virus-free medium. Efficiency of gene transfer and localization was examined by fluorescence microscopy. En face confocal microscopy of the corneal endothelial surface was used to image recombinant E2F2 expression. 5-bromodeoxyuridine (BrdU) incorporation was used to examine progression to the S phase. Changes in density of the corneal endothelium were quantified by specular microscopy and counting of trypan-blue-stained cells. Apoptosis was tested with a TUNEL assay. Recombinant proteins were expressed predominantly in the endothelium and in a high proportion of endothelial cells in the first week after exposure to virus, diminishing thereafter. Compared with the control, transduction with E2F2 resulted in progression from the G(1) to the S phase in a significant number of cells and in increased cell density. Apoptosis was not found to any significant extent. Overexpression of the transcription factor E2F2 in nonmitotic human corneal endothelial cells results in short-term expression, cell-cycle progression, and increased monolayer cell density.

Confocal Microscopy of Posterior Polymorphous Endothelial Dystrophy

To report the in vivo confocal microscopic findings of posterior polymorphous endothelial dystrophy (PPED). Four patients with PPED from 2 unrelated families and 2 asymptomatic children of an index patient were included in this observational case series. The eyes of the 6 subjects were examined by confocal light microscopy. Confocal microscopy demonstrated craters, streaks, and cracks over the corneal endothelium surface. Pleomorphism and polymegathism were present in eyes with PPED. Guttae and clusters of abnormal endothelial cells were also identified in corneas of these PPED patients. These findings were absent in eyes without clinical manifestations of PPED. In vivo confocal microscopy is potentially useful for excluding suspected cases of subclinical PPED. Abnormalities in the Descemet membrane and endothelium were observed.

Observation of the posterior endothelial surface of the rabbit cornea using atomic force microscopy.

To study the surface of normal corneal endothelium by means of atomic force microscopy (AFM). The central corneal endothelial posterior surface of New Zealand white rabbits was examined. Specimens were observed in Balanced Salt Solution using the contact mode of the AFM either fresh or after fixation in cacodylate-buffered glutaraldehyde solution. Removal of sialic acid residues and hyaluronic acid was achieved by means of enzymatic treatment with neuraminidase and hyaluronidase. Observation of the fresh specimens revealed the presence of an apical endothelial surface coating material (glycocalyx). Removal of sialic acid residues and hyaluronic acid after enzymatic treatment using neuraminidase and hyaluronidase, respectively, permitted the elucidation of the structure of the nondigested coating material. Fixation of the samples resulted in removal of the surface coating material. The imaging of the fixed endothelium surface revealed the mosaic of polygonal cells with the apical flaps of cell junctions emerging over the cell surface. The cell shape and the other characteristics of the posterior surface fixed endothelium were comparable to those described in the literature using scanning electron microscopy. The scanning of very small ranges has provided high-resolution images at the nanometer level in fixed and fresh corneal endothelial surfaces. The atomic force microscope represents a new powerful imaging tool permitting high-resolution observation of corneal endothelium surface in fresh and minimally prepared fixed specimens.

Corneal endothelial response to induced myopia in the chicken.

To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. 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. 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. 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.

Epithelial ingrowth following penetrating keratoplasty: a clinical, ultrasound biomicroscopic and histopathological correlation

E pithelial ingrowth is a serious complication of intraocular surgery and penetrating ocular trauma. It rarely occurs after penetrating keratoplasty. 1•2 The surface epithelium proliferates inside the eye, forming epithelial cysts or sheetlike anterior segment ingrowth. Clinically the epithelial ingrowth appears as a hazy membrane with a distinct, greyish border representing the leading edge of the epithelial sheet. The membrane may extend posteriorly over an intraocular lens, ante­ rior vitreous, ciliary body and retina. The diagnosis of epithelial ingrowth may be difficult, particularly in cases with complete or near complete growth of epithelium over the corneal endothelial surface. The posterior extent of the ingrowth may also be difficult to determine preoperatively. In this report we describe the clinical and patholog­ ical features of a patient with epithelial ingrowth fol­ lowing penetrating keratoplasty. Our case demon­ strates the possible role of ultrasound biomicroscopy (UBM) in determining the posterior extent of the membrane.

New method to measure the retention of viscoelastic agents on a rabbit corneal endothelial cell line after irrigation and aspiration

Purpose: To quantify the surface retention of several ophthalmic viscoelastic agents following irrigation and aspiration (I/A) using a new in vitro method.Setting: Alcon Laboratories, Inc., Fort Worth, Texas, USA.Methods: A rabbit corneal endothelial cell line was cultured to confluency in 24-well plates, and the cells were labeled quantitatively with internalized neutral red dye. Five ophthalmic viscoelastic agents were applied to cover the monolayer of cells: sodium hyaluronate (Healon®, Provis®, and Amvisc Plus®), Formulation A (a dispersive, nonproteinaceous, synthetic polymer), and sodium chondroitin sulfate, sodium hyaluronate (Viscoat®). Irrigation and aspiration (with fluid turbulence similar to that encountered in phacoemulsification surgery) were performed on each well for 3 minutes, using 120 mL of balanced salt solution with bicarbonate, dextrose, and glutathione (BSS Plus®). The cells were treated with an acidified ethanol solution to extract the dye from the cells left without a viscoelastic cover. The extracted dye was measured by spectrophotometry and compared with the total dye recovered from control cells.Results: The retention value, which represented the percentage of cells with viscoelastic retained on the surface, was calculated as follows: Healon, 7; Provisc, 16; Amvisc Plus, 17; Formulation A, 55; Viscoat, 90. On a nonadsorptive, non-cell surface, the retention values of the five viscoelastics were significantly less than those on cells.Conclusion: The results of this experimental model suggest that cohesive viscoelastics are readily removed from the cells, while dispersive viscoelastics are highly retained. In addition, mutual surface interaction (electrical charge and other properties) plays a significant role in determining the retention of viscoelastics on the corneal endothelial cell surface following I/A.

Isolation and characterization of a unique natural killer cell inhibitory factor present in the anterior chamber of the eye.

The eye is a classic example of an immunologically privileged organ. Immune privilege in the anterior chamber is a multifaceted phenomenon that may have evolved to protect delicate ocular tissues from immune-mediated damage. The anterior chamber of the eye is lined with corneal endothelial cells, which are terminally differentiated cells that are incapable of regeneration. Since corneal endothelial cells are crucial for maintaining corneal clarity, damage to these cells leads to impairment of vision and, in some cases, blindness. The absence of constitutive expression of MHC class I molecules on corneal endothelial cells makes them potential targets for NK cell-mediated cytolysis. The aqueous humor (AH) that fills the anterior chamber of the eye and bathes the corneal endothelial surface contains numerous immunomodulatory molecules, such as TGF-beta, which may protect the corneal endothelium from NK cell-mediated damage. Functionally significant levels of TGF-beta are present in AH. In this study, we demonstrate that AH inhibits NK cell-mediated cytotoxicity in vitro, but does not affect cytotoxic T lymphocyte-mediated lysis. The inhibitory effect was immediate and occurred without preincubation of NK cells with aqueous humor. The inhibitory factor could not be neutralized by Abs to TGF-beta, but was abrogated by treating AH with proteases. Inhibition was not simply due to lysis of NK cells, since AH did not alter NK cell viability. Initial purification using gel filtration chromatography showed that the activity was restricted to a single elution peak. Analysis of the active fractions by gel electrophoresis indicated that the inhibitory factor was a single protein of approximately 10 kilodaltons. The NK inhibitory factor might be an important modulator for protecting the corneal endothelium from unbridled NK cell-mediated injury and, thus, might be instrumental in preserving vision.

Temperature measurements during phacoemulsification and erbium:YAG laser phacoablation in model systems

Purpose: To compare the potential for thermal injury to ocular structures resulting from phacoemulsification ultrasound energy and erbium:YAG (Er:YAG) laser output.Setting: Morse Laser Laboratory, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.Methods: Ultrasonic phacoemulsification energy and Er:YAG laser output (10 J/cm2, 10 Hz, 0.3 watts) sufficient for lens removal were applied to model systems and human cadaver eyes. Temperatures were measured with ultrafine thermocouples interfaced to a microcomputer data acquisition system.Results: Although greater than 95% of energy from laser output is converted to thermal energy, temperature rise in model systems and cadaver eyes was 10 to 15 times greater after pulsed application of ultrasound energy than after Er:YAG laser application. At 100% power, ∼4 watts of ultrasound power is converted to heat. Temperature rise following both laser and ultrasound applications decreased with irrigation in cadaver eyes and increasing volume in a model system. With continuous irrigation (20 cc/min), the temperature rise at 2 minutes measured at the corneal endothelial surface, within the corneal stroma, and in the anterior chamber angle of cadaver eyes was ∼0.5 degrees Celsius (°C) after laser application and 7.0°C after ultrasound application. Without irrigation, temperatures rose 2.5°C after laser application and 35.0°C after ultrasound application.Conclusion: At operating parameters sufficient for lens removal, the Er:YAG laser imparted less thermal energy to whole eyes and model systems than ultrasonic phacoemulsification.

Corneal Endothelial Polymerization of Histoacryl Adhesive: A Report of a New Intraocular Complication

Tissue adhesive are commonly used in ophthalmology to seal small corneal perforations. We report a case of inadvertent instillation of cyanoacrylate adhesive (Histoacryl) in the anterior chamber resulting in polymerization of the glue on the corneal endothelial surface, with iridocorneal and iridolenticular adhesion.

Receptors for Hyaluronan on Corneal Endothelial Cells

Previous investigations suggest that the corneal endothelium has specific binding sites for hyaluronan (HYA). In the present study, biochemical and immunological techniques were used to characterize these binding sites and to compare them with the liver endothelial cell (LEC) HYA receptor. Affinity chromatography of solubilised. 125I-labelled corneal endothelial cell surface proteins on immobilised HYA proved that there were molecules that were strongly bound to the polysaccharide. A part of these molecules formed a 100-kDa band when analysed by autoradiography after SDS polyacrylamide electrophoresis (PAGE). A specific antibody against the rat LEC HYA receptor was used for immunohistochemical studies of monkey and human corneas. There was a specific staining of the corneal endothelium of both species, and hyaluronan treatment before isolation of the human eyes reduced the staining intensity. Hyaluronidase treatment of the tissue sections before receptor staining strikingly increased the specific staining of the corneal endothelial cells (CEC). Immunoblotting of human corneal proteins, separated by SDS-PAGE, showed staining at 200, 150-160 and 55 kDa. Uptake experiments of tritiated HYA in cultured monkey CEC showed only a slight increase in cell associated radioactivity over 2-6 hr. The results make it unlikely that the corneal endothelial receptor, like its liver endothelial counterpart, is actively involved in receptor-mediated endocytosis. Our studies suggest that CEC carry receptors for HYA that are immunologically similar to the LEC receptors. CEC receptors might act as binding structures increasing the concentration of HYA close to the CEC as a protection of these vulnerable cells from physicochemical damage.

A gel of glycosaminoglycans lining the anterior and posterior chambers in man: histochemical evidence at light and electron microscopy levels.

A thin mucous layer covers the ciliary body and iris epithelium and becomes thicker in the anterior chamber where it covers the anterior surface of the iris, the chamber angle and corneal endothelial surface. It is especially thick at the chamber angle, where it adopts a meniscus shape with the concavity towards the anterior chamber. Cetylpiridinium chloride along with glutaraldehyde was used to precipitate this layer of mucous substance lining the anterior and posterior chambers of the human eye. The staining of the precipitate by cationic dyes suggests that glycosaminoglycans are main components. The specific characterisation with anti-hyaluronic acid monoclonal antibody labelled with colloidal gold reveals the presence of hyaluronic acid in the precipitate. Long unbranched hyaluronic acid molecules may form the skeleton of a gel able to trap and hold virtually any other macromolecule suspended in the aqueous humour. A possible role of such a gel in the regulation of aqueous humour outflow is discussed.