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G Coscas

Publications and source records attributed to G Coscas.

At least 91 records · Page 5Linked to original sources
PubMed1994

Antiphospholipid antibodies in retinal vascular occlusions. A prospective study of 75 patients.

OBJECTIVE: To assess the prevalence of antiphospholipid antibodies in patients with occlusive retinal vascular disorders. PATIENTS: Seventy-five consecutive patients (44 with central retinal vein occlusions, 24 with branch venous occlusions, five with vasculitis plus branch venous occlusion, and two with arterial occlusions) were screened for antiphospholipid antibodies and compared with a control group composed of outpatients with similar systemic vascular disorders. RESULTS: The antibody assay for one patient was positive for lupus anticoagulant and the antibody assay for three other patients was positive for anticardiolipin antibodies. These four patients had central or branch retinal vein occlusion and presented with several vascular risk factors. Comparison of the retinal vascular occlusion and the control groups showed no difference in the levels of anticardiolipin antibodies or lupus anticoagulant. CONCLUSIONS: Antiphospholipid antibodies did not seem to be a feature of retinal vein occlusion, but in rare cases (5%) they may contribute to the occlusive phenomenon. A systematic screening does not seem to be justified, but it may be valuable to test for antiphospholipid antibodies in patients without conventional risk factors and in patients with clotting screen abnormalities, particularly if associated with lupus-like syndrome or other elements of the primary antiphospholipid syndrome.

Adult↗
PubMed1994

Superoxide inhibits proliferation and phagocytic internalization of photoreceptor outer segments by bovine retinal pigment epithelium in vitro.

Experiments were performed to investigate the effect of free radical damage on two aspects of retinal pigmented epithelium (RPE) metabolism, namely, proliferation and phagocytosis. Bovine RPE cells were maintained in monolayer cultures, either as passaged (for proliferation and lysosomal activity assays) or primary cultures (for phagocytosis measurements). Free radicals (superoxide anions) were generated by a xanthine oxidase (XO)-hypoxanthine (HX) reaction. Total phagocytosis (binding plus ingestion of rod outer segments (ROS)) was quantitated by radioimmunoassay using a specific anti-opsin antibody and iodinated secondary antibody. In some cases, agents with known or possible protective influences against oxidative damage, i.e., superoxide dismutase (SOD), vitamin E, and basic fibroblast growth factor (bFGF), were tested for their activity in this model system. RPE cell proliferation was inhibited in a HX-XO dose-dependent manner, in the absence of cell toxicity. Modifications of cell morphology were also noticed. Either simultaneous exposure of RPE cells to ROS membranes and HX-XO or pretreatment of ROS membranes with HX-XO prior to their addition to RPE monolayers led to a statistically significant 20-30% decrease in phagocytosis relative to control values. This decrease was essentially observed in the binding phase of phagocytosis, indicating damage to ROS surface molecules as the primary event. Addition of SOD or vitamin E prevented this loss of phagocytic activity, whereas bFGF had no effect. Superoxide radicals did not, however, affect phagocytosis when RPE cells were exposed to them alone, prior to incubation with ROS; nor did they alter a later stage in the phagocytic process, acid phosphatase activity. This tissue culture model represents a convenient system for analyzing free radical damage in different aspects of RPE-photoreceptor behavior and may be useful in studying this phenomenon in several retinal disorders.

Acid Phosphatase↗
PubMed1994

Spontaneous evolution and photocoagulation of diabetic cystoid macular edema.

Cystoid macular edema (CME) causes progressive visual impairment in diabetic patients and its treatment by photocoagulation remains unsatisfactory. We observed its spontaneous evolution for 3 years in 31 eyes. CME resolved in 9 eyes, was fluctuant in 16 and worsened in 7. Mean group visual acuity (VA) remained unchanged. Two modalities of photocoagulation were studied. In 27 eyes exhibiting CME combined with circinate exudates (group 1), extramacular focal photocoagulation was applied to the center of the exudates. Exudates disappeared from 23 eyes and CME from 12 eyes. Mean group VA remained unchanged. In 24 eyes with CME but without exudates (group 2), perifoveolar grid photocoagulation was applied over the CME area. CME disappeared from 15 eyes. Mean VA remained unchanged. These results show that CME with exudates requires a two-step treatment, comprising first focal photocoagulation, which clears exudates and often improves CME, and second--but only if CME persists and VA is below 0.5- perifoveolar grid photocoagulation, which often clears CME and stabilizes VA.

Adult↗
PubMed1994

Biomicroscopy and fluorescein angiography of pigmented iris tumors. A retrospective study on 44 cases.

The classification of pigmented iris tumors is a difficult clinical problem. Based on the retrospective observation of colour photographs and iris angiograms of 44 pigmented iris tumors observed over 19 years, the authors present an original grading scheme with scores depending on both the biomicroscopical and the fluoroiridographic patterns of the tumors. The biomicroscopical parameters considered were: thickening of the iris in the area of tumor, pupillary distortion and/or ectropion uveae and uneven pigment density. The fluoroiridographic parameters were: early visibility of the anomalous tumoral network, hyperfluorescence inside or around the tumor, and dye leakage at sites remote from the mass. Based on the score of each tumor, the 44 cases were divided into 3 groups with the different degrees of malignancy confirmed by either histological examination or by follow-up behaviour. The authors suggest that routine use of biomicroscopic-fluoroiridographic classification of pigmented iris tumors would be useful.

Female↗
PubMed1994

Elevated erythrocyte aggregation in patients with central retinal vein occlusion and without conventional risk factors.

BACKGROUND: Retinal venous circulation is characterized by the combination of a low flow state and a high vascular resistance, which would make it particularly dependent on blood viscosity. Erythrocyte aggregation is the chief determinant of blood viscosity at low shear rates. Recent studies have demonstrated increased erythrocyte aggregation in many systemic vascular disorders and also in retinal vein occlusion. METHODS: To assess the possible role of abnormal hemorheologic findings in the pathogenesis of central retinal vein occlusion (CRVO), the authors retrospectively studied erythrocyte aggregation and hematocrit and fibrinogen levels in 33 patients with CRVO and without any known risk factors (diabetes, hypertension, smoking, hyperlipidemia, cardiovascular disease, glaucoma). Erythrocyte aggregation was assessed with a light back-scattering method. Results were compared with those of a group of 33 age- and sex-matched controls. RESULTS: Eleven (33%) of the 33 patients with CRVO had abnormal hemorheologic findings. Erythrocyte aggregation was highly significantly increased in the CRVO group when compared with the control group (P < 0.0001), as was the hematocrit level (P < 0.05). In addition, the proportion of patients with abnormal blood rheologic tests was greater (50%) in the subgroup of patients who initially had nonischemic CRVO that worsened into an ischemic CRVO during the follow-up. CONCLUSION: These data suggest that abnormal hemorheologic findings could affect the pathogenesis of CRVO, and perhaps be predictive of an aggravation. The latter hypothesis needs to be confirmed in a larger, prospective study.

Adult↗
PubMed1994

[Albinism].

Explore the source record for details and available documents.

Adolescent↗
PubMed1994

[Viral vasculitis and disseminated white spots].

A case of retinal vasculitis is reported, unusual because of its occurrence in a young healthy man, and especially because of the presence of a turn-over of white spots in the mid-peripheral retina, which faded and turned into areas of pigment epithelium changes. The patient presented with anterior uveitis with raised intraocular pressure, and then with vitritis, retinitis in the peripapillary area with involvement of the optic disc, vasculitis with perivascular sheathing and vascular occlusion. Clinical and laboratory investigations remained negative. The lesions regressed with antiviral treatment (Ganciclovir) and steroids. Final visual acuity was 20/400 due to optic disc atrophy and the development of an epimacular membrane. The authors discuss the differential diagnosis of retinal vasculitis related to immunological diseases or viral infection. In conclusion, this case may constitute a mild type of acute retinal necrosis syndrome.

Fluorescein Angiography↗
PubMed1993

[Severe myopia or myopia-disease?].

An increased axial length over 26 mm is one of the characteristics of highly myopic eyes. High myopia represents a marked type of the refraction disorders in which distance vision is impaired and leads to wear glasses in childhood. But this high myopia is also a degenerative myopia due to the distension of the whole envelopes of the ocular bulb mainly at the posterior part of it. Prevalence of high myopia in the general population ranges from 1 to 4%. The disease is usually inherited and transmitted in a dominant fashion. Degenerative myopic eyes are potentially blind eyes due to many complications occurring during lifetime at the choroidal or retinal level. Vision threatening retinal detachments are frequent and severe, and are sometimes related to a macular hole. Other diseases including glaucoma and cataract are more frequently encountered in those eyes but may be managed with higher success. Specific oculo-motor disturbances and strabismus are also encountered. At present, the main risk threatening central vision is macular disease with lacquer cracks and hemorrhages associated with subretinal new vessels growth. Only laser photocoagulation can halt the progression of the disease and avoid or delay severe loss of central vision.

Adolescent↗
PubMed1993

[The macula lutea in myopia].

High or degenerative myopia is associated to abnormalities of the posterior pole of the eye. Their expansion with time progresses to the occurrence of complications, especially neovascular ingrowth in the central macular area. The natural evolution of these new vessels results in loss of central vision at long term. Photocoagulation of the new vessels, sparing initially the center, has delayed the loss of central vision at 2 years in our randomized clinical trial. Only treated eyes retained useful acuity at 5 years. New therapeutic modalities will be possible when the mechanisms of occurrence of degenerative myopia are elucidated.

Humans↗
PubMed1993

[Surgery of macular neovascular subretinal membranes].

Vitreoretinal surgical techniques were recently used to eradicate subfoveal choroidal neovascularization which is usually associated with a poor visual prognosis. A series of 102 patients who underwent this surgery with a small retinotomy was reviewed. There were 62 eyes with age-related macular degeneration, 35 eyes with presumed ocular histoplasmosis, and five eyes with other etiologies. Retinal pigment epithelium patches were associated in seven eyes. Significant improvement in vision was achieved in 33% of eyes with age-related macular degeneration. Final visual acuity was 20/200 or worse in 84% of eyes. Visual prognosis was unchanged in eyes with retinal epithelium patches. In presumed ocular histoplasmosis, response to surgery seemed better: visual improvement was achieved in 44% of eyes and final visual acuity was 20/70 or more in 33% of eyes. During a one year follow-up, recurrent choroidal neovascularization, macular pucker and retinal detachment were observed in 27%, 11% and 5.6% of eyes respectively. Long term follow-up and randomized clinical trials comparing laser and surgical treatments are required for evaluation of surgical removal. At present, surgical removal does not reduce rates of choroidal neovascularization recurrence.

Aged↗
PubMed1993

[HERETAIN: a computer-assisted diagnosis system for hereditary retinal syndromes].

The diagnosis of hereditary retinal syndromes may be difficult for a physician because of their number and variability. A computer assisted diagnosis of these syndromes can be useful in such cases. We used an identification software (XPER) for this purpose. The data base contains more than 67,000 elementary data that enable us to define 115 hereditary retinal syndromes. The knowledge is not represented by description of typical cases or diagnostic procedure rules but by structured description of syndromes defined by the group of experts. This CAI software is characterised by specific optimising procedures, deductive algorithms and dissimilarities calculus and enables very fast diagnoses by limiting the number of complementary analyses and thus the cost of this research. This system is extensible and justifies all its conclusions, its user-friendly data representation makes it accessible for any physician even if he does not master computers. The selected pathology field seems very suitable to developing a computer assisted diagnosis system: many low frequency syndromes, meaningful precise diagnosis for genetic and professional counseling, therapeutic expectations due to progress in molecular genetics. According to the authors, HERETAIN is one of the largest computer assisted decision support systems in ophthalmology.

Diagnosis, Computer-Assisted↗
PubMed1993

[Corneal crystalline deposits in benign monoclonal gammopathies. Apropos of 3 cases].

Unusual corneal crystalline opacities at the level of Bowman's membrane and superficial stroma were observed in 3 patients with benign monoclonal gammopathy. Corneal immunohistochemical examination showed that the deposits consisted of immunoglobulin crystals identical to the paraprotein found in the serum (with the same light chain: Kappa in 2 cases and Lambda in the third case). The factors and mechanisms governing intracorneal immunoglobulin deposition in the cornea are discussed.

Adult↗
PubMed1993

[Retinal detachment following posterior capsulotomy using Nd:YAG laser. Retrospective study of 144 capsulotomies].

Nd:YAG capsulotomy is currently performed after extracapsular cataract surgery and seems to increase the risk of postoperative retinal detachment. In order to evaluate the incidence of this complication in our experience, we retrospectively studied 144 patients who underwent Nd:YAG laser posterior capsulotomy with at least a six-month follow-up. Six patients out of 144 (4.16%) subsequently developed rhegmatogenous retinal detachment. The average time from extracapsular cataract surgery to YAG capsulotomy was 21 months (11 to 26 months). The average time from capsulotomy to retinal detachment was 3.6 months (1 to 8 months). In 4 out of 6 eyes, at least one risk factor for retinal detachment was present (myopia, lattice degeneration, retinal detachment in the fellow eye). Vitreous cells were observed in 4 patients after capsulotomy. In 2 patients, a prophylactic laser photocoagulation had been previously performed. These retinal detachments were not different from aphakic or pseudophakic detachment, but the examination of retinal periphery was particularly difficult because of the peripheral capsular fibrosis, hiding retinal tears in 4 eyes. Two cases of moderate proliferative vitreoretinopathy were observed. Retinal reattachment surgery was successful in all cases with one procedure. The YAG laser energy required to create a capsulotomy was less than that reported in the literature, and no relationship could be established with the total energy applied. Nd:YAG capsulotomy seems to moderately increase the risk of retinal detachment, especially in myopic patients. The mechanisms of vitreous and retinal damage after Nd:YAG capsulotomy are discussed.

Aged↗