High-resolution 1H NMR spectroscopy of aqueous humour from rabbits

Background: Detection of different substances in aqueous humour is important for evaluation of the disorders affecting the eye. The purpose of the present study was to apply highresolution proton (¹H) nuclear magnetic resonance (NMR) spectroscopy for extensive characterisation of the metabolites in the aqueous humour from rabbits. Methods: High-resolution ¹H NMR spectroscopy, including two-dimensional shift correlated (COSY) technique, was performed on aqueous humour from rabbits. Results: More than 20 metabolites were simultaneously detected and identified in high-resolution ¹H NMR spectra of aqueous humour from rabbits. Some of these were also quantified. Conclusion: High-resolution ¹H NMR spectroscopy is a valuable method for simultaneous detection of many different metabolites in aqueous humour.     

Prolyl hydroxylase inhibitor and lysyl hydroxylase inhibitor inhibit spreading of corneal epithelium

Background: The spreading of epithelium is critical in the healing of corneal wounds. Such epithelial spreading requires the continuous production of protein and glycoprotein. To determine whether collagen production is required for the spreading of corneal epithelium, we studied the effects of inhibitors for collagen production on spreading of corneal epithelium in vitro. Methods: We examined the effect of two proline analogs, l-azetidine 2-carboxylic acid and cis-hydroxyproline, a prolyl hydroxylase inhibitor, ethyl-3,4-dihydroxybenzoate, and a lysyl hydroxylase inhibitor, minoxidil, on the spreading of epithelium of organ-cultured rabbit cornea. Results: Both analogs and inhibitors inhibited epithelial spreading in a dose-dependent manner. Conclusion: These observations indicate that collagen production may be involved in the spreading of corneal epithelium.     

The effect of normal childbirth on eyes with abnormalities predisposing to rhegmatogenous retinal detachment

Background: Pregnant women who have high myopia, a history of retinal detachment or retinal holes, or have known lattice degeneration are frequently referred to an ophthalmologist for advice concerning the management of pregnancy and labor, i.e. whether a spontaneous vaginal delivery can be allowed and whether prophylaxis for high-risk retinal pathology is indicated. Many obstetricians still believe that pregnant women with ocular abnormalities predisposing to rhegmatogenous retinal detachment should have an instrumental delivery, and a few even advocate cesarian section. Very little has been written about the management of pregnant women with high-risk retinal pathology, and opinions differ considerably. Patient data on this subject are scarce. Methods: We studied 10 women who had 19 deliveries (10 prospective and 9 retrospective) and who had a history of retinal detachment, had been diagnosed as having extensive lattice degeneration, or had been treated for symptomatic retinal holes or breaks. The women were followed from the third trimester of pregnancy through labor and delivery into the postpartum period, looking for changes in the retinal status. Results: We found no changes in the retinal status in the postpartum examination. Conclusion: We conclude that prenatal treatment of asymptomatic retinal pathology is not indicated and that spontaneous vaginal delivery may be allowed to take place in women with high-risk retinal pathology.     

Proteinases in subretinal fluid

Background: Degradation of the extracellular matrix by secreted proteases is connected to cell migration and proliferation in invasive growth and in scar tissue formation. In retinal detachment, retinal pigment epithelium (RPE) cells loosened from their monolayer are often seen in the subretinal fluid (SRF) and the vitreous, where they may participate in the scar tissue formation of proliferative vitreoretinopathy. To evaluate the role of SRF constituents on the release of RPE cells, we analyzed SRF in patients with retinal detachment for the presence of enzymes able to degrade extracellular matrix. Methods: SRF was collected altogether from 16 patients undergoing retinal reattachment surgery and analyzed for activities against some of the key enzymes in extracellular proteolysis, namely collagenases, gelatinases, elastase and cathepsin G. Results: Seventy-two-kilodalton gelatinase was found in all SRF samples studied, whereas the neurophil-type 92-kDa gelatinase could not be detected. Low collagenase, elastase and cathepsin G activities could also be detected in some samples. Conclusions: The predominant type of matrix metalloproteinase present in SRF is the 72-kDa MMP-2. The proteolytic activity in SRF may be connected to the release of RPE cells into SRF and to degradation of components of the vitreous exposed to SRF.     

Alterations in anterior segment dimensions in eyes with retinitis pigmentosa

Background: In visually deprived primate eyes there is a correlation between alterations in growth parameters and changes in retinal neurotransmitters. Progressive retinal degeneration also leads to alterations in retinal neurotransmitters. In this study we wanted to investigate whether alterations in the dimensions of the anterior eye segment are also present in human donor eyes of patients with hereditary retinal degeneration. Methods: Sagittal sections through anterior segments of 47 eyes from donors with different types of retinitis pigmentosa (RP) and of 59 eyes from normal donors were investigated morphometrically using a PC-based morphometric system. Results:. In the RP eyes there was a significant shortening of the distance between the peripheral end of Descemet's membrane and the posterior end of Schlemm's canal and of the length of the pars plana of the ciliary body. These changes varied markedly among the different types of RP. The most pronounced shortenings were found in eyes of men with X-linked recessive RP, which had the most severe retinal changes. RP eyes showed, in contrast to normal eyes, significant age-related elongation of the ciliary body and the chamber angle. A significant increase of the axial diameter with age was also found in RP eyes. Conclusion: Our study reveals for the first time that there are changes in the anterior segment dimensions in human eyes with hereditary retinal degeneration. Measurements of anterior eye segment parameters might provide additional indices for the severity of RP and for the diagnosis of RP subtypes.     

Midline granuloma presenting as orbital cellulitis

Background: Lethal midline granuloma usually presents with rhinorrhoea and redness of the skin above the nose. Early ocular symptoms are very rare. We here describe a patient who presented with acute orbital cellulitis. Patient: A 73-year-old woman had a 24-h history of severe pain around her left eye. We saw the typical clinical picture of orbital cellulitis. A CT scan revealed a diffuse infiltration of the left upper and lower lid, the anterior orbit and the ethmoidal sinuses. Result: On surgical exploration we found a granular, partly necrotic tumour. Histological examination revealed an angiocentric nasal T-cell lymphoma (midline granuloma). Conclusion: Midline granuloma should be included in the differential diagnosis of acute orbital cellulitis.     

Pyogenic granuloma of the cornea: report of a case and review of the literature

Background: Pyogenic granulomas are ulcerated vascular proliferations, often accompanied by inflammatory infiltrates, which rarely affect the eye. Only few reports on pyogenic granulomas of the cornea have been presented. Methods: The enucleated globe containing the corneal tumor was examined histopathologically, and special immunohistochemical stains were performed. Results: The lesion had a yellowish appearance with marked vascularization. The inflammatory infiltrate was mainly composed of mononuclear cells, with no multinucleated giant cells, and was located anterior to Bowman's layer, leaving the corneal stroma unaffected. Immunohistochemical studies outlined the high vascular content, even in dense cellular areas, and confirmed the inflammatory nature of the mononuclear infiltrates. Conclusions: Pyogenic granuloma of the cornea represents a clinical and morphological entity developing in a traumatized eye with corneal vascularization. Although the origin of these lesions remains obscure, there have been no signs of malignancy. Therefore, enucleation of an eye with a pyogenic granuloma should be avoided.     

Functional neuroanatomy of visual object naming: a PET study

Background: The ability to name objects depends partly on visual perception. We used positron emission tomography (PET) to measure activity-related changes in regional cerebral blood flow (r-CBF) in order to identify regions of the brain activated during visual object naming. Methods: Four right-handed volunteers were recruited. Following an intravenous injection of¹⁵O-labeled water, r-CBF was measured during visual object naming, counting numbers, and resting. PET and MRI images were coregistered, the size of the brain was proportionally adjusted in each axis to Talairach's and Tournoux's atlas, and the comparison of stimulated versus resting blood flow images revealed activated brain regions. Results: In the subtraction of resting from naming, activation was observed in the bilateral primary visual cortex, bilateral fusiform gyrus, left lingual gyrus, bilateral inferotemporal cortex, bilateral inferior frontal gyrus, bilateral precentral gyrus, anterior cingulate gyrus, left parietal operculum, and left putamen. In the subtraction of counting from naming, most of the those areas were activated, but no significant activity was observed in the left lingual gyrus, left parietal operculum, or bilateral precentral gyrus (motor cortex). The areas activated with the paradigm included those dedicated to visual perception (primary and associate visual cortex), visual recognition (inferior temporal cortex), and phonological output (Broca's area). Conclusion: Our results indicated that the major neural network from occipital lobe to frontal cortex, which is mainly involved in the ventral visual pathway, demonstrated activation in these tasks. Result of this study will serve as base line data for analyzing the findings in patients with impaired visual perception.     

Therapeutic intervention with chicken egg white ovomacroglobulin and a new quinolone on experimental Pseudomonas keratitis

Background: Chicken egg white ovomacroglobulin (ovoM) is a potent protease inhibitor with broad-spectrum activity against various proteases. The combined effects of ovoM and the new quinolone, ofloxacin (OFLX) on experimental Pseudomonas aeruginosa keratitis were investigated. Methods: The in vitro inhibitory effects of ovoM on protease activity in culture fluid of clinically isolated P. aeruginosa and on activity of human neutrophil elastase and cathepsin G were assayed using azo-casein as substrate. Albino rabbits received intrastromal injection of the isolated Pseudomonas strain (1 × 10⁵ colony-forming units). At 16 h after inoculation, three treatment groups -0.1% ovoM alone, 0.3% OFLX alone, and a combination of both —and a non-treatment control group were tested. Results: Protease activity in the culture solution and human neutrophil elastase was inhibited by ovoM, whereas cathepsin G was not inhibited effectively. In vivo additive therapeutic effects of ovoM and OFLX were observed at 96 h (P < 0.05 compared with OFLX alone). Conclusion: The results indicate that inhibition of proteolytic activity with ovoM is useful in preventing stromal degradation in P. aeruginosa keratitis.     

Indirect immunofluorescence study of the cornea and the conjunctiva in a xenogeneic system: analysis of humoral reactivity in patients with Wegener's granulomatosis

Background: Ocular involvement in patients with Wegener's granulomatosis (WG) can cause progressive loss of vision. The pathophysiological events leading to the WG-specific ocular inflammation are unknown. Methods: A method involving indirect immunofluorescence on bovine and porcine corneoconjunctival frozen sections was used to detect antibodies to corneal and conjunctival epithelium in serum samples from patients suffering from WG with ophthalmic involvement (orbital granuloma or ocular vasculitis, both active and inactive phase). Normal persons and WG patients without ophthalmic involvement served as control groups. Anti-human IgG, IgA and IgM were tested. Results: Five different immunofluorescence patterns could be distinguished in each species. There were differences in the reactivity with bovine and porcine tissue. Every pattern was caused mainly by human IgG. The antibodies were directed to the cell nuclei or to extranuclear structures. All patterns also occurred frequently in normal sera. No pattern was found that occurred specifically in the serum of patients with WG and ocular inflammation. Conclusions: The results indicate that this immunofluorescence system does not detect a characteristic antibody profile that could be attributed to the serum of WG patients. Hence the approach lacks clinical usefulness as a diagnostic procedure.     

Vasoactive intestinal peptide- and nitric oxide synthase-containing nerve fibers in the rat ophthalmic artery have different origins

Background: Neuropeptides are important in the regulation of vascular functions. The purpose of the present study was to investigate the distribution of perivascular nerve fibers containing neuropeptides and nitric oxide synthase (NOS) in the rat ophthalmic artery. Methods: Neuropeptide-and NOS-containing nerve fibers in the rat ophthalmic artery were identified using immunocytochemistry following unilateral parasympathectomy (electrocoagulation of the sphenopalatine ganglion) and sympathectomy (superior cervical ganglionectomy). The contralateral artery was used as control. Results: Nerve fibers containing vasoactive intestinal peptide (VIP), neuropeptide Y (NPY) and NOS were abundant in the wall of the ophthalmic artery. Nerve fibers containing calcitonin gene-related peptide and substance P were scarcer. Following destruction of the sphenopalatine ganglion there was no discernible change in the density of VIP- and NPY-immunoreactive fibers, while the majority of the NOS-containing fibers disappeared. Following sympathectomy the NPY-containing nerve fibers were almost completely eliminated, whereas VIP- and NOS-containing fibers were unaffected. Conclusion: The present study demonstrates that the sphenopalatine ganglion is the main contributor of NOS-containing nerve fibers to the rat ophthalmic artery. In contrast, this ganglion apparently is of little importance as a source of VIP-immunoreactive nerve fibers to the artery, demonstrating different origins of the majority of the VIP-and NOS-containing fibers to this artery. The NPY-containing nerve fibers in the rat ophthalmic artery emanate mainly from the superior cervical ganglion.     

Retinal and disc neovascularization in Behçet's disease and efficacy of laser photocoagulation

Background: The vasoocclusive episodes resulting from Behçet's disease can cause capillary dropout and vascular remodeling. Retinal and disc neovascularizations, which occur as a result of occlusive vasculitis, can cause recurrent vitreal hemorrhages and neovascular glaucoma leading to severe visual impairment. Methods: 1080 eyes of 540 patients with Behçet's disease were examined between 1973 and 1993. Of the 912 eyes with posterior segment involvement, laser photocoagulation could be performed in 13 of 25 eyes with disc neovascularization (NVD), 12 of 22 eyes with retinal neovascularization (NVE), and 4 of 6 eyes with NVD and NVE. Laser was directed at areas of NVE and retinal capillary nonperfusion. In cases of NVD, panretinal photocoagulation was performed. Results: The rate of regression of NVD was significantly greater in laser-treated eyes than in the untreated group. The results were similar in cases of NVD with NVE. In eyes with NVE which underwent laser photocoagulation, the NVE regressed. None of the treated eyes developed neovascular glaucoma during the follow-up period. Vitreous hemorrhage occurred in two laser-treated eyes. Conclusion: Laser photocoagulation is successful in preventing complications of retinal and disc neovascularizations. Thus, in cases of occlusive vasculitis associated with Behçet's disease, laser photocoagulation should be considered for prevention of complications such as vitreous hemorrhage and neovascular glaucoma.Presented at the meeting of the Club Jules Gonin, Versaille, France, 8-13 September 1994     

Experimental use of space-retaining substances with extended duration: functional and morphological results

Background: In glaucoma surgery, e.g. cyclodialysis ab interno, to date no viscous substances have been available that stay in the cyclodialysis cleft long enough to prevent scarring. We examined the qualities of two different viscoelastic substances that stay longer in the place of instillation than hyaluronic acid. Methods: We performed cyclodialysis ab interno in 12 eyes of six owl monkeys. The right eyes were treated with the gel with the higher molecular weight, the left eyes using the gel with the lower molecular weight. The baseline data of intraocular pressure and outflow facility were compared to the values measured postoperatively up to the 140th day. Histological examination of the eyes followed. Results: There was no statistically significant difference between the two substances. The mean intraocular pressure decrease was 7.9 (±2.9) mmHg in the right eyes and 4.8 (±2.7) mmHg in the left eyes. The histological examination showed that the gel had remained in the cyclodialysis cleft without signs of inflammation. In contrast to other viscoelastic substances studied previously, the substances in this study performed their space-retaining function without decreasing outflow facility. Conclusion: Both substances are suitable means of improving the rate of success of cyclodialysis ab interno, as they remain where they are instilled long enough to prevent wound scarring in the cyclodialysis cleft.     

Corneal endothelial permeability and aqueous humor flow using a standard protocol

Background: The study was carried out to compare corneal endothelial permeability and aqueous flow values of healthy volunteers measured in different countries with identical fluorophotometers using a standardized protocol. Method: Healthy volunteers aged between 20 and 70 years were studied in five European cities. Fluorescence scans of the anterior segment of both eyes were made using a commercial fluorophotometer. Beginning 4 h after instillation of four drops of fluorescein 10%, 12 scans of the anterior segment of each eye were performed in 2 h. The values of corneal endothelial permeability and aqueous flow were calculated with standardized software from the decay of the fluorescein concentration in the cornea and anterior chamber. Results: The mean permeability values (× 10^–4 cm·min^–1)±SD were 3.7-1.6 (n=19; Coimbra, Portugal), 4.3-1.1 (n=19; Frankfurt, Germany), 3.9±0.9 (n=19; Leiden, The Netherlands) and 5.4±1.2 (n=10; Milan, Italy). The values were not significantly different (ANOVA, P>0.3), except those in Milan. The mean flow values (l·min^–1) ±SD were 2.3±0.9 (n=17; Coimbra), 1.9±0.7 (n=10; Cologne, Germany), 2.6±1.2 (n=19; Frankfurt), 2.0±0.6 (n=19; Leiden) and 1.7±0.8 (n=10; Milan). The values were not significantly different (Kruskal-Wallis test, P>0.1). Conclusions: Permeability and flow values in the different cities had similar values and standard deviations. The Concerted Action demonstrated the usefulness of a standardized protocol.Concerted Action supported in part by the European Commission, on Ocular Fluorometry: Standardization and Instrumentation Development of the 4th European Community Medical and Health Research Programme (No. MR 4^*/0314/P).     

Immunoscintigraphy for ocular melanoma: a reliable diagnostic technique?

Background: Immunoscintigraphy (IS) has recently been used as a diagnostic tool for ocular melanoma. We wanted to re-evaluate published data in our own patients and to correlate immunoscintigraphic results with histologic findings and immunohistochemical characteristics of the tumour tissue. Methods: During a 4-year period, IS was performed on 35 patients (average age 64 years) with suspected ocular melanoma by i.v. injection of 225.28S, a monoclonal antibody against high-molecular-weight melanoma-associated antigen. Histology was available in 22 cases. Tumour tissue was evaluated for cell type, vascularization, necrosis, pigmentation, and lymphocytic infiltration, and immunohistochemistry was performed with 225.28S and antibodies against HMB-45, S-100 and vimentin. One hundred and two patients with metastasizing cutaneous melanoma served as controls. In these patients the identical immunoscintigraphic technique was applied. Results: IS yielded a positive result in about 50% of our patients with ocular melanoma, while in patients with cutaneous melanoma sensitivity was 89%. In five patients who turned out not to have melanoma, two false-positive results were obtained (one subretinal hemorrhage and one Wegener's granulomatosis). No correlation was found between any of the histological features or the immunoreactivity pattern and the immunoscintigraphic outcome. However, antigenic differences between ocular and cutaneous melanoma were evident. Conclusion: We conclude that IS, using the antibody applied in this study, is of only limited value in patients with ocular melanoma. Our results suggest that antigenic differences, rather than histological characteristics or technical problems, are responsible for the low sensitivity in ocular melanoma compared to cutaneous melanoma.Presented in part at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Sarasota, Florida, 1–6 May, 1994     

The influence of penetrating keratoplasty and cyclosporin A therapy on MHC class II (Ia)-positive cells in the rat iris and choroid

Background: The presence of Ia-positive cells (MHC class II equivalent) has been previously reported in the iris and choroid of various species. They have been reported to have both round and dendritic morphologies; the latter may represent classic dendritic cells, potent antigen-presenting cells (APCs). It is possible that the dendritic-like cells play a important role in (auto)immune processes of uveal and other ocular tissues. Using the flat or whole mount technique, the distribution of Ia-positive cells in the rat iris and choroid was investigated following penetrating Keratoplasty (PKP) and following treatment with cyclosporin A (CsA). Methods: Lewis (LW) rats received corneal buttons from Lewis-Brown Norway (LW-BN) donors and were randomly assigned to the following groups: (i) operated, untreated (n=24); (ii) operated, CsA-treated (10 mg/kg i.m.;n=22). Controls were groups (iii) normal LW rats (n=13); (iv) unopcrated, CsA-treated (16 days' treatment;n=8); (v) anterior perforation of the anterior chamber (n=3); (vi) eight corneal sutures only (n=4); (vii) syngeneic operated (LW to LW;n=4). Animals of groups (i) and (ii) were killed on the 5th, 9th and 13th postoperative days and on appearance of the corneal rejection (group i, day 13; group ii, day 16). Both eyes were enucleated, immediately fixed, and iris-choroid flat mounts were examined for Ia-positive cells using APAAP immunohistochemistry. Results: In the normal Lewis rat iris, scattered Ia-positive cells of both nondendritic and dendritic morphology were observed. CsA treatment in the unoperated rat did not result in a significant decrease in the percentage of dendritic cells in the iris or choroid. Anterior chamber perforation, the placement of sutures in the cornea and syngeneic PKP resulted in a moderate increase in iris Ia-positive cells. Allogeneic transplantation resulted in a large increase in both types of Ia-positive cells, particularly on day 13 with corneal rejection. In group ii, an initial decrease in Ia-positive cells until day 13 was observed; upon rejection (day 16), the histological picture was similar to that of untreated animals. Alterations in the operated choroid were also apparent following CsA treatment. Conclusion: Corneal transplantation in the Lewis rat results in an increase in Ia-positive cells in the iris; CsA therapy can delay but not prevent this reaction. Changes in choroidal Ia-positive cells following PKP were not apparent, their numbers being affected only by CsA treatment following grafting.     

The influence of δ9-Tetrahydrocannabinol on intraocular pressure in the anaesthetized cat

⁹-Tetrahydrocannabinol (⁹-THC) was injected both intravenously and into the brain stem via the left vertebral artery. Contrary to results obtained with clonidine, neither the fall in intraocular pressure (IOP), nor the arterial hypotension induced by ⁹-THC, were enhanced after the central administration of the drug. For clonidine, a central mechanism underlying the ocular hypotensive effect has recently been proposed. This suggestion is based upon the enhanced fall in IOP after central administration of clonidine. The pontomedullary area is considered to be the main initial target of this drug. Obviously, the IOP-lavering mechanism of ⁹-THC is different from that of clonidine.     

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.     

Cyclosporine-A in the treatment of serpiginous choroiditis

Summary Seven patients affected by bilateral inflammatory serpiginous choroiditis have been treated with Cyclosporine-A for 6-21 months. Nine outof the fourteen eyes showed a significant improvement in their visual acuity; five eyes did not change.Cyclosporine-A may, therefore, be considered effective in the treatment of this disease.Its usefulness seems to be greater when the serpiginous choroiditis is in its acute stage; chronic stages, however, also seem to improve under treatment.Its main indication is, in our opinion, the involvement of the macular region of the second eye, when the first eye is already damaged. We consider Cyclosporine-A, in these situations, to be a first choice treatment.     

Quantitative analysis of immunogold labellings of collagen types I,III, IV and VI in healthy and pathological human corneas

Background: We studied the distribution of collagen types I, III, IV and VI in one healthy human cornea and in seven pathological human corneas, in which the disorders were three cases of pseudophakic bullous keratopathy (two severe, one moderate) and one case each of stage IV keratoconus, chronic ulcer, vascularized cornea and disciform keratitis. Methods: Transmission electron microscopy examinations were performed on post-embedding immunogold-labelled sections. The staining was evaluated by gold particle count in the different tissues. The presence or absence of a given antigen was determined by statistical analysis, using a d-value test. Results: Our results on healthy corneal tissues corroborate the data available from previous studies, except for collagen type VI, which we found to be absent in Bowman's layer. In pathological corneas with a collagenous layer posterior to Descemet's membrane, collagen types I, III and especially IV were detected in this collagenous layer. Collagen types I, III and VI were detected in the anterior healed stroma of other pathological corneas, except for the keratoconus cornea, in which intense collagen III staining was observed. Conclusion: The presence of collagen types I and III in the posterior collagenous layer of our pseudophakic bullous keratopathy corneas suggests that this layer corresponds to scar tissue secreted by stimulated endothelial cells.