Effect of α2-macroglobulin on retinal glial cell proliferation

Background Activation of the receptor for 2-macroglobulin (2M), the low-density lipoprotein-related protein (LRP1; CD91), has been suggested to represent a possible strategy for the inhibition of uncontrolled retinal cell proliferation via stimulation of the clearance of 2M-bound growth factors and proteinases from the extracellular space. In order to prove this assumption, we investigated the effect of 2M on the proliferation of Müller glial cells in vitro.Methods Proliferation assays using bromodeoxyuridine were carried out on cultured Müller glial cells of the guinea pig in the absence and presence of 2M.Results Activated 2M evoked a slight increase of the cell proliferation at control conditions. Addition of 2M to the culture medium inhibited the proliferation evoked by agonists of G-protein-coupled receptors [adenosine 5-triphosphate (ATP), neuropeptide Y]. However, 2M did not diminish the proliferation evoked by agonists of receptor tyrosine kinases (epidermal and platelet-derived growth factors) and by serum, respectively. Inhibition of LRP1 by a neutralizing antibody did not alter the ATP-evoked proliferation while it increased the proliferation in the presence of 2M.Conclusion It is concluded that 2M inhibits the proliferation evoked by agonists of G-protein-coupled receptors, possibly via enhanced growth factor clearance by LRP.     

A comparison of colour Doppler imaging of orbital vessels and other methods of blood flow assessment

Background: Comparison of the haemodynamic measurements obtained by colour Doppler imaging and other methods of ocular blood flow measurements was desired. Methods: The blood velocity findings from colour Doppler imaging of patients with central retinal vein occlusion were compared to the results of fluorescein video-angiography, continuous tonography and ophthalmodynamometry. Results: Patients with low or undetectable blood velocities in the central retinal vein had longer retinal dye transit times on fluorescein video-angiography. Tonography showed a positive correlation with the velocities in the ophthalmic artery, but ophthalmo-dynamometry showed a negative correlation with these velocities. Conclusion: The relationships between the blood velocities in orbital vessels and other blood flow measurements emphasise that there is a complex interaction of the blood flow parameters. Care must therefore be taken when interpreting the results of studies.     

Galactose-containing glycoconjugates of the iris,the aqueous outflow passages and the cornea in capsular glaucoma

Background: The aim of the study was to compare galactose-containing glycoconjugates of the iris, the aqueous outflow pas sages and the cornea with exfoliation material in capsular glaucoma. Methods: Six formalinfixed, paraffin-embedded human eyes with capsular glaucoma and six control eyes were studied by using a panel of 11 biotinylated lectins to galactose- and N-acetylgalactosamine-containing glycoconjugates. Results: The Gal ( 3) GaINAc-reactive lectins peanut agglutinin (PNA) and Bauhinia purpurea alba agglutinin (BPA) and the Gal (14)GlcNAc-reactive lectins Ricinus communis agglutinin (RCA-I) and Phaseolus vulgaris erythroagglutinin (PHA-E) gave the strongest label with exfoliation material. Lectin binding to the iris was variable. The binding of PNA, BPA, RCA-I, Erythrina cristagalli agglutinin (ECA), PHA-E and Glycine max agglutinin (SBA) to the subendothelial region of iris blood vessels closely resembled their binding to exfoliation material. RCA-I and PHA-E bound moderately to the aqueous outflow passages. The surface of the corneal epithelium showed positive reaction with most lectins studied, but the keratocytes reacted with RCA-I and PHA-E only. Neuraminidase pretreatment generally increased the reaction intensity. Conclusions: The findings suggest that the glycoconjugate composition of exfoliation material in the classical locations along the anterior and posterior chamber closely resembles that in the subendothelial region of iris blood vessels.The authors have no financial interest in any product or process mentioned herein     

Tolerance of human fetal retinal pigment epithelium xenografts in monkey retina

Background: RPE transplantation offers the possibility of treating certain forms of retinal degeneration. Understanding how to optimize the surgical technique for performing RPE transplantation, especially in primates, is therefore of considerable interest. Methods: Fifteen patch RPE transplants were performed in six monkeys. The transplant sites were examined at follow-up by ophthalmoscopy, biomicroscopy, fluorescein angiography and histology. Foveal and peripheral retinal transplants were compared. Results: Human fetal RPE xenografts can survive without rejection for at least 6 months after transplantation in monkey retina. Such grafts form a basal lamina and make intimate contacts with the outer segments of the host. Both rods and cones retain a normal appearance when in contact with unrejected transplants. Rejection occurred in only 30% (3/10) of the peripheral but in 60% (3/5) of the foveal transplants. Conclusions: Cultured human fetal RPE patch transplants can survive and maintain local photoreceptor integrity for relatively long periods of time in monkey subretinal space without immunosuppression. Rejection, when it occurs, is more frequent near the fovea.     

Influence of oxygen free radicals and free radical scavengers on the growth behaviour and oxidative tissue damage of bovine retinal pigment epithelium cells in vitro

Purpose: This investigation was carried out to ascertain whether oxygen free radicals can influence the growth behaviour and consecutive lipid peroxidation of retinal pigment epithelium (RPE) cells in vitro and whether scavengers can counteract these effects. Methods: The experimental model was based on calf RPE cells. Hypoxanthine/xanthine oxidase (HX/XO) and superoxide dismutase/catalase (SOD/CAT) served as the radical generating system and scavengers, respectively. The components were tested alone and in combination. Lipid peroxides were determined in culture supernatants by a thiobarbituric acid assay. Results: Concentrations of up to 100 mol/1 of HX alone and 500/1000 U of XO alone, as well as the application of the scavengers without the radical generating system (HX/XO), had no effect. Doserelated reduction of cell growth and increase of lipid peroxidation were found with HX/XO treatment (single dose of 500 and 1000 U/ml 24 h after seeding). After application of 500 or 1000 U/ml of XO, CAT, when given alone (1200 U/ ml), counteracted the effect of the radicals on cell growth and lipid peroxidation; SOD (300 U/ml) had no effect. A combination of SOD and CAT was no better than the effect of CAT alone. Conclusion: The prevention of radical-induced reduction of cell growth and lipid peroxidation by scavengers supports trials of therapy using antioxidants and/or free radical scavengers for various ocular syndromes with RPE involvement.     

Integrins in human anterior chamber angle

Background: Integrins, which are composed of an and subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation.Methods: The distribution of the integrin (₁, ₃-₅) and (_1–6 and _v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique.Results: Immunoreaction for the ₁ subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the ₃ subunit was found in the TM and the cribriform layer only. In infant eyes the ₅ subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The ₆ subunit was localized to the endothelium of SC only. Immunoreaction for the _v subunit was present in the TM and the cribriform layer of infants and young adults.Conclusion: The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.     

Adhesion molecules in normal and pathological corneas

Background: Adhesion molecules are cell surface receptors that are probably important in various cell-cell and cell-extracellular matrix interactions of the cornea. Method: In this immunohistochemical light-microscopic study we analyzed the expression pattern of adhesion molecules in normal and pathological human corneas (cases of corneal inflammation and degenerative disorders). The analyzed molecules included the 1 integrin or VLA family VLA-1-6, the 2 integrins or leukocyte integrins LFA-1, Mac-1, and p150,95, the immunoglobulins LFA-3, CD2, ICAM-1 and VCAM-1 and the selectins ELAM-1 and GMP-140. Results: Inflamed cornea (in contrast to normal cornea). On corneal epithelium, increased expression of the 2 subunit of VLA-2 was detected and ICAM-1 was induced on the basal epithelial cells. On corneal stromal keratocytes, LFA-3 was induced and expression of the subunits of VLA-1-6 and ICAM-1 was increased. On vascular endothelium, VCAM-1 and ELAM-1 were induced and ICAM-1 and GMP-140 expression was increased. On corneal endothelium, ELAM-1 was induced and increased levels of the 1 subunit of VLA-1 and GMP-140 were expressed. Degenerative disorders (in contrast to normal cornea): In corneas with degenerative disorders we found decreased expression of adhesion molecules. Conclusion: Inflammatory cytokines increase the expression of the adhesion molecules. Increased expression of the VLAs probably promotes cell-extracellular matrix and cell-cell interactions. ICAM-1, VCAM-1, LFA-3, ELAM-1 and GMP-140 expression was increased on vascular endothelium in inflamed corneas. Corresponding receptors on leukocytes probably enable a selective recruitment of different leukocyte populations in inflammatory corneal diseases. The decreased expression of adhesion molecules in corneal degenerative disorders is probably a sign of reduced cell-cell and cell-extracellular matrix interactions.     

Optic disc histomorphometry in normal eyes and eyes with secondary angle-closure glaucoma

Parapapillary atrophy has been reported to occur in glaucoma eyes. Seeking the microscopical equivalent, we evaluated histomorphometrically serial sections of 21 human eyes enucleated due to secondary angle-closure glaucoma and 28 nonglaucomatous eyes with malignant choroidal melanoma. In the parapapillary region two zones were differentiated: in zone B adjacent to the optic disc, Bruch's membrane was denuded of retinal pigment epithelium cells; zone A peripheral to zone B showed pigment irregularities in the retinal pigment epithelium. Both zones B and A were significantly larger and zone B occurred more frequently in glaucomatous eyes than in the control group. Additionally, the outer and inner retinal layers and the parapapillary retina as a whole were significantly thinner in the glaucoma eyes than in the control eyes. Photoreceptors were completely lost or markedly decreased in number in zone B The findings may indicate that zones B and A represent the histological correlate of the glaucomatous parapapillary chorioretinal atrophy. Offprint requests to: J. JonasSupported by Deutsche Forschungsgemeinschaft DFG Nan 55/61/Jo, and Förderverein Augenheilkunde Erlangen     

Retinal pigment epithelial cells: autocrine and paracrine stimulation of extracellular matrix contraction

Background: This study was carried out to examine the biological activity of contraction promoters produced by dedifferentiating retinal pigment epithelial cells (RPE) and to evaluate the importance of autocrine and paracrine effects within a semi-closed environment like the vitreal cavity. Methods: RPE at different stages of dedifferentiation in culture were examined for their ability (a) to generate tractional forces in vitro, with and without serum stimulation, and (b) to produce and release contraction-stimulating proteins. Autocrine versus paracrine effects of cell-secreted promoters were tested by using RPE or human dermal fibroblasts (HDF) as target cells. The contraction-stimulating activity of the cell-secreted promoters was partially characterized and compared to the activity of defined promoters. Results: Our study confirmed that RPE can synthesize and secrete cell-contraction-promoting factor(s) active in stimulating the development of tractional forces by RPE as well as HDF. The quantity of biological activity secreted per cell decreases with progressive dedifferentiation, yet the responsiveness of the cell to contraction promoters increases. The contraction promoter(s) synthesized by RPE is partially distinct from the promote rs in serum, TGF-1 and 2, IGF-1, ET-1 and PDGF. The contraction-promoting effects of the RPE product(s) can be completely blocked by staurosporine. Conclusion: Dedifferentiation of RPE is characterized by increasing capacity to generate tractional forces and decreasing synthetic capacity. RPE within a semi-closed system like the vitreal cavity can, theoretically, act both as promoting and active component of traction-related events (tractional retinal detachment).     

Transforming growth factor-β regulates human retinal pigment epithelial cell phagocytosis by influencing a protein kinase C-dependent pathway

Background: Transforming growth factor- (TGF-) plays an important role in the pathogenesis of many ocular diseases, including proliferative vitreoretinopathy. We examined the effect of TGF- on the phagocytosis of rod outer segments by retinal pigment epithelium (RPE), which is a major function of RPE, and investigated the dependence of this effect on the protein kinase C (PKC) pathway. Methods: Phagocytotic uptake of fluoresceinated bovine rod outer segments was determined by flow cytometry. RPE cells were treated with TGF-1 or TGF-2 and their effects on phagocytosis were examined. The effects of various PKC inhibitors (calphostin C, staurosporine, and extended exposure to phorbol 12-myristate 13-acetate, PMA) and a stimulator (brief exposure to PMA) on RPE phagocytosis was evaluated. Results: Both TGF-1 and TGF-2 up-regulated RPE phagocytosis and PMA abolished the upregulating effect of TGF-. In contrast, PKC inhibition by staurosporine and calphostin C resulted in increased phagocytosis. A combination of TGF- and PKC inhibitor treatment did not produced any additive effect on phagocytosis. Conclusion: We concluded that TGF- up-regulates human RPE phagocytosis, but that this effect is counteracted by PKC activation. It is possible that this TGF--induced effect is due, in part, to a negative modulation of the PKC-dependent pathway.     

Effects of norfloxacin on the retina in rabbits

Background: Fluoroquinolones have a strong affinity with melanin, and their ocular effects have been reevaluated. Norfloxacin, one of the fluoroquinolones, has broad-spectrum activity against aerobic gram-positive and gram-negative bacteria. We examined the retinal toxicity and intraocular pharmacokinetics of intravitreal norfloxacin in rabbits. Methods: Twenty-three albino and 23 pigmented rabbits were divided into three groups to evaluate retinal toxicity and two groups to investigate the intraocular pharmacokinetics. Each of these five groups was further divided into two subgroups (albino rabbits and pigmented rabbits). Results: With 500 Etg norfloxacin, the oscillatory potential of the electroretinogram was transiently and selectively deteriorated in albino and pigmented rabbits, whereas the electroretinogram remained unchanged with 50 g in pigmented rabbits. No changes were observed in the visual evoked potential or on histology of the retina 7 days after an intravitreal injection of 50 or 500 ltg norfloxacin. The electroretinogram and the retinal histology became abnormal 7 days after four intravitreal injections of 500 g norfloxacin at 7-day intervals. As regards the intraocular pharmacokinetics after an intravitreal injection, the norfloxacin concentration in the chorioretina was as high as that in the vitreous 3 h after injection and was much higher than that in the vitreous 7 days after injection. Similar results were obtained after multiple injections. Conclusion: These results indicate a high concentration of norfloxacin in the melanin-containing ocular tissues.     

Some aspects of cataract morphology: A SEM-study

Two lenses from patients of very advanced age with senile cataracts were processed for SEM, fractured equatorially, sputtered with Au and examined by SEM. In the cross-fracture various areas could be observed. Although the overall structure of the lens-fibres appeared to be intact, higher magnifications showed that the len-fibre material had changed into a brittle structure, with either a granular appearance or a fibrillar character. At other places clearly recrystallization of lens-fibre proteins had taken place, with the formation of finger-like substructures, sometimes organized into plate-like structures or running parallel to each other in a kind of undulating pattern.Between the various areas of chemically changed lens-fibre material certain canal-like areas were found with cellular structures, the so-called waterclefts or Wasserspalten. Structures which, together with the chemical change in the lens proteins, account for the dramatic change in light dispersion.The work was carried out at the Centre for Medical Electron Microscopy, 69/2 Oostersingel, 9713 EZ Groningen.     

Woher stammen die Leukocyten in der lädierten Hornhaut?

Zusammenfassung Es wird zunächst klargestellt, daß bei einer zentralen Hornhautläsion während der ersten Stunden keiner der im Wundbereich zahlreich vorhandenen Leukocyten vom Limbus her eingewandert ist. Auf Grund verschiedener Versuchsanordnungen kann dargetan werden, daß es auch bei weitgehender Ausschaltung einer möglichen Leukocyteneinwanderung durch den Bindehautsack, in der zentralen Cornea zum Auftreten zahlreicher leukocytoider Zellen kommt. Es wird sodann der direkte Übergang der Kerne der Hornhautparenchymzellen in leukocytoide Zellen dargestellt und aufgezeigt, daß die in loco entstandenen leukocytoiden Zellen beim Kaninchen die gleichen pseudoeosinophilen Granulationen aufweisen wie die Blutleukocyten. Ferner wird auf den Prozeß der Zellumwandlung am Wundrande eingegangen: Er setzt ein mit einer, bei Silberfärbung (färberisch am besten 2–3 Tage nach der Läsion) erkennbaren, deutlichen Vergrößerung und eventuellen Vermehrung der (fünf) Chromatinkörperchen, die zu neuen Kernen werden, während die übrige Kernsubstanz als neues Cytoplasma in Erscheinung tritt. Etunden nach der Läsion) der Verlauf aber auch so darstellen, daß es zunächst zu einem weitgehenden Verlust der Kernfärbbarkeit (genau so auch mit anderen Färbungen: H.E., Feulgen usw.) kommt unter gleichzeitiger Auflockerung der Kern-und Cytoplasm-Struktur. Es folgt die Bildung eines unregelmäßigen und sich fleckig anfärbenden Areals (häufig an Stelle der alten Zelle), dann die Verdichtung der dunkleren Stellen dieses Areals zu neuen leukocytoiden Kernen, die in ihrer Form jetzt den schon beschriebenen vergrößerten Chromatinköperchen entsprechen. Die Entstehung zahlreicher neuer Zellen in loco kann auch sehr schön nach Injektion eines artfremden Serums in die Hornhautmitte verfolgt werden (Wesselysches Phänomen). Nach 12–14 Tagen tritt bei einer Anzahl von Kaninchen dann ein konzentrischer im Hornhautparenchym liegender grauer Ring auf, in dem histologisch—je nach der verstrichenen Zeit—die Entstehung der verschiedensten Zellformen zu beobachten ist (von kleinsten Chromatinbröckeln, präleukocytoiden Zellen bis zu zahlreichen fertigen Leukocyten). Sodann wird die Reaktion von Hornhautepithelzellen (auf eine Verbrennung hin) und deren Umwandlung in Entzündungszellen gezeigt. Auf Grund der Ergebnisse der verschiedenen Versuchsanordnungen und der morphologischen Befunde wird der Schluß gezogen, daß die bei rein zentraler Hornhautschädigung zu beobachtenden Leukocyten zum großen Teil (wahrscheinlich die meisten) in loco durch Umwandlung von Hornhautepithel- und Hornhautstromazellen (sowie von Grundsubstanz?) entstanden sind.Mit 4 Textabbildungen     

Vitamin E succinate inhibits proliferation and migration of retinal pigment epithelial cells in vitro: therapeutic implication for proliferative vitreoretinopathy

Background Retinal pigment epithelial (RPE) cells play an important role in proliferative vitreoretinopathy (PVR). Vitamin E succinate is an ester form of a potent biological antioxidant, vitamin E, and has unique effects on various cells. We examined the effect of vitamin E succinate on proliferation and migration of cultured bovine RPE cells, since these are critical steps in the development of PVR. Methods Bovine RPE cells were cultured in minimal essential medium (MEM) containing 10% fetal calf serum (MEM-10). Cells were incubated with MEM-10 containing 25 M vitamin E, vitamin E succinate, butylated hydroxytoluene BHT) or d-mannitol. Cell proliferation was assessed by counting cell numbers on days 2, 4 and 6. ³H-Thymidine uptake was also examined in RPE cells incubated with various forms of vitamin E — vitamin E, vitamin E succinate, Trolox, -tocopherol, vitamin E acetate, vitamin E phosphate, vitamin E nicotinate — or antioxidants — BHT or d-mannitol (25 M each). RPE cell migration was studied as follows: small area (5×15 mm) of confluent cultured RPE cells was denuded using a straight razor blade and incubation was continued for 20 h with MEM-10 containing vitamin E, vitamin E succinate, -tocopherol or BHT. The number of cells that migrated into the denuded area from the wound edge in each microscopic field (×20) was counted and expressed as a percentage of control (MEM-10 alone). Results The antioxidants, vitamin E and BHT, stimulated RPE cell proliferation and ³H-thymidine incorporation compared with the control, while vitamin E succinate significantly inhibited both proliferation and ³H-thymidine uptake (IC₅₀, 23 M Other forms of vitamin E or d-mannitol had no effect. Neither vitamin E nor BHT had a significant effect on RPE cell migration (108.2% and 112.6% of control, respectively), but vitamin E succinate inhibited migration (58.3%). Cell viability, assessed by the trypan blue dye exclusion test, was not impaired by a 3-day incubation with 50 M of vitamin E succinate. Conclusions An ester form of a physiological antioxidant, vitamin E succinate, inhibits RPE cell proliferation and migration without causing cellular toxicity. These findings suggest its therapeutic potential for the pharmacological treatment of PVR.     

Toxicity of 1-(β-d-arabinofuranosyl)cytosine after intravitreal injection in the rabbit eye

The retinal toxicity of intravitreally injected 1-(-d-arabinofuranosyl)cytosine (cytarabine) was examined in 7 chinchilla rabbits to determine if cytarabine can be used as local therapy for vitreoretinal non-Hodgkin's lymphoma. Fractionated dose of 600 g, 1500 g, and 2700 g cytarabine in stabilized saline were given intravitreally in one eye (2 × 300 g, 5 × 300 g, and 3 × 900 g, respectively, with an interval time of 24 h) and stabilized saline in the other eye as control. Toxic effects were evaluated with biomicroscopy, direct ophthalmoscopy, fluorophotometry, electroretinography, light, and electron microscopy. Toxic effects were found with the 1500 g and 2700 g doses only. They consisted of a temporary impairment of the blood retina barrier function for fluorescein as measured by fluorophotometry and an irreversible change of the b-wave in the electroretinograms. No histopathologic changes were seen under the light microscope. Electron microscopic examination showed aberrations in the synaptic pedicles of the photoreceptor cells at a dose of 1500 g cytarabine. The results suggest that the cytarabine dose that is expected to be therapeutic for vitreoretinal non-Hodgkin's lymphoma (about 90 g given in three doses of 30 g) is non-toxic for ocular structures.Correspondence to: J.A. van Best     

β-Galactosidase transgene expression in transplanted rabbit retinal pigment epithelial cells in vivo

Background: Intraocular transplantation of genetically modified cells that release a particular substance could have a major impact on the treatment of various ocular diseases. We studied the expression of the reporter gene -galactosidase (lacZ) in transplanted retinal pigment epithelial (RPE) cells in vivo Methods: RPE cells from pigmented rabbits were transduced with the -galactosidase gene in a retroviral vector. Cells were then assayed for gene expression and transplanted subretinally into the eyes of New Zealand White rabbits. RPE cells that were transduced with a similar vector without the -galactosidase gene were used as controls. Rabbits were killed on days 1, 7, and 21 and the eyes processed for transmission electron microscopy Results: Neomycin-resistant rabbit RPE cells that showed -galactosidase activity were generated within 2–5 weeks. After transplantation, viable RPE cells that expressed the transgene and that phagocytosed rod outer segments were observed on days 1, 7, and 21 Conclusions: The results show that generation of genetically modified RPE cells is feasible and that the transplanted cells remain viable and continue to express the transgene in the subretinal space of the host animal for at least 21 days. Transplantation of such genetically modified RPE cells could provide a new tool for studying retinal diseases and, potentially, for correcting metabolic abnormalities in retinal degenerations and dystrophies.     

Bemerkungen zuW. Burkl undF. Schwabs Arbeit: „Histologischer und immunhistologischer Nachweis der lokalen Antikörperbildung in der Hornhaut”

Zusammenfassung Die Bezeichnungen Wanderzellen und Leukocyten für die Entzündungszellen der Hornhaut sind falsch und experimentell widerlegt.Dem örtlichen Charakter der Keratitiden entspricht die vonBurkl undSchwab nachgewiesene örtliche Entstehung von Antikörpern in der Hornhaut.Albrecht v. Graefes Arch. Ophthal.161, 168–184 (1959).     

Electrophysiological evidence that early glaucoma affects foveal vision

The pattern electroretinogram (PERG) and visual evoked potential (PVEP) were recorded simultaneously using a 1.1 cpd pattern which was counterphase modulated at 1 Hz. The responses of ocular hypertensive (OHT) eyes (with normal visual fields) and eyes with early glaucoma (with early visual field defects and/or early cupping of the optic nervehead) were compared to age-matched normal observers. All patients (26 eyes) and normal observers (14 eyes) had normal transient flash electroretinograms. Delays were seen in mean PERG latency in both OHT and early glaucoma eyes, while mean PERG amplitude was significantly reduced only in the early glaucoma eyes. The PVEP responses were unmeasurable in 11/26 patient eyes because the waveforms were grossly abnormal in shape, making it impossible to identify the N- and P-components. The data were categorized in this manner: a patient response was considered abnormal if latency or amplitude exceeded normal limits (PERG or PVEP) or if the waveform was unmeasurable due to its shape (PVEP only). Of the 26 patient eyes, we found that 8 eyes had normal PERG and PVEP, 11 eyes had abnormal PERG and PVEP, one eye had an abnormal PERG and a normal PVEP, and 6 eyes (3 patients) had a normal PERG and an abnormal PVEP. These data support the proposition that foveal vision (as assessed by the PVEP) may be affected by early glaucomatous damage. The relationship between the PERG and PVEP also was evaluated using a new measurement which we call the latency window. Using this measurement, 15/26 patient eyes were abnormal - 9 of these had unmeasurable PVEPs. This measurement could be useful in classifying W-shaped PVEPs as normal or abnormal.This study was supported in part by Grants EY01708 and EY01867 from the National Eye Institute, Bethesda, MD, by Fight For Sight Grant-in-Aid G-274, and by an unrestricted grant from Research to Prevent Blindness, Inc., New York, NY.     

Eye references in the Homeric Epics

After a short introduction to the Homeric Epics, the name of Homer and the time and place where the poems were written, the authors refer to the terms of the eyes and to the verses where they are found. Among these terms, the most important is the term oaó, the first term for the eye in ophthalmology, which has remained throughout the years unchanged.Finally, they refer to the injuries of the eyes, the participation of the two sons of Asclepios in the Trojan campaign and to the verses including the classical paragraph ... a doctor is more capable than the other men ...Both Epics relating to the cardinal human values: prudence, temperance, fortitude and justice, contain the lofty ideal of human excellence, called by the Greeks a.     

Orthotopic corneal transplantation in the mouse — a new surgical technique with minimal endothelial cell loss

Background: The murine model of orthotopic perforating keratoplasty is important for studying the allograft reaction, but the small dimensions cause technical difficulties. Methods: The anterior chamber of the eye of the BALB/c mouse was measured with the confocal microscope and with histological methods. Ten C3H mouse donor corneas each were separated by the conventional technique and by the newly developed underwater technique, where the opened donor eye did not lose its shape under water. The corneal endothelium was stained with trypan blue and alizarin red S. Ten BALB/c (H-2d) mice received a corneal graft taken from a C3H (H-2k) mouse by the underwater technique. Results: The 3.7-mm eye of the BALB/c mouse has a corneal diameter of 3.5 mm. The cornea has a central thickness of 170 m, the epithelium comprising 30% and the stroma 70%. While none of the corneas separated by the new underwater technique evidenced endothelial damage, a 28 ± 17.0% defect of the endothelial surface was found with the conventional technique. All transplanted corneas were clear when the lids were opened on the 2 post-operative day and clouded between the 7th and 30th days (mean 16.5 days) due to an allograft reaction. Conclusion: The newly developed underwater technique is superior to the conventional technique, since floating of the very thin donor cornea during the separation procedure prevents endothelial defects by guarding against folds. By enabling reliable keratoplasty in the mouse, this technique facilitates studies on the experimental allograft reaction.