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Biomedical subjects

G Coscas

Publications and source records attributed to G Coscas.

At least 217 records · Page 12Linked to original sources
PubMed1983

The effects of red krypton and green argon laser on the foveal region. A clinical and experimental study.

The destruction of senile neovascular membranes in the central avascular region of the macula by argon laser is difficult and associated with complications. Yellow pigment in this region absorbs the blue component of the conventional argon laser radiation. In this study, the authors used lasers of different wavelengths: red krypton and green argon. Optical and electron microscopic studies on nonhuman primates were performed at 1 hour and 6 weeks. Maximum damage was seen at the level of the internal choroid with krypton laser and at the level of the pigment epithelium with green argon laser. A clinical and angiographic study showed that the destruction of the juxtafoveal neovascular membranes by both lasers was possible. Our clinical experience suggests that the red krypton laser offers a better alternative for treatment of neovascular membranes located near the foveola than the green argon laser.

Animals↗
PubMed1983

Birdshot retinochoroidopathy and subretinal new vessels.

Decrease of visual acuity in birdshot retinochoroidopathy is due either to optic atrophy or to 3 types of macular involvement: cystoid macular oedema, geographic atrophy, or macular serous detachment. We describe 3 cases of juxtapapillary subretinal neovascularisation occurring in long-standing birdshot retinochoroidopathy. The mechanism of the formation of the new vessels is discussed.

Adult↗
PubMed1983

Quantitative evaluation of fluorescein angiograms: microaneurysm counts.

This study describes a method for quantifying microaneurysms (MA) from fluorescein angiograms. The method was validated by the reproducibility of the number of MA in 30 angiograms read twice each by two independent observers; and by the absolute difference in MA counts between two readings by the same observer, and difference in numbers counted by two different observers. The precise location of each MA on two readings was also studied and the reproducibility of location varied from 60 to 71%, depending on the quality of the angiograms. Clinicians and technicians working in the same or in different centers obtained similar results. The coefficient of correlation between observers and between readings was satisfactory, r greater than 0.9. The method is easy to learn and the reproducibility allows for its use in clinical trials.

Aneurysm↗
PubMed1983

[Hemorrhagic macular choroidopathy in the young subject].

In a group of 182 patients of under 50 years of age with subretinal neovascularization, the syndrome of hemorrhagic macular choroidopathy of the young adult was identified in 30 cases. This syndrome is characterized by the occurrence of a juxtafoveolar idiopathic neovascular membrane in an eye normal in all other respects. The natural course of this lesion is the production of a fibroglial scar leading to a mean final visual acuity of 0.15. The syndrome remains unilateral in 75 p. cent of cases, as shown by a mean follow-up of 23.9 months. Photocoagulation of these new vessels is possible, and in a group of 19 eyes it allowed conservation of a mean acuity of 0.6. This syndrome differs from ocular histoplasmosis where widespread uni- or bilateral involvement of the pigment epithelium and choriocapillaris is found. Hemorrhagic macular choroidopathy can also be distinguished from choroiditis associated with hemorrhages. The existence or the sequellae of uveitis, even when associated with subretinal new vessels arising from an atrophic chorioretinal scar, establishes the correct diagnosis. The etiology of hemorrhagic macular choroidopathy is unknown. It is possible that multiple etiologic agents might be responsible for different clinical syndromes in relation to endemic factors.

Adolescent↗
PubMed1983

[Preretinal neovessels in toxoplasmic uveitis].

Preretinal and prepapillary new vessels developed in a case of severe ocular toxoplasmosis. Fluorescein angiography failed to demonstrate any area of ischemic retina. Neovascularization disappeared with medical treatment and ocular inflammation resolution.

Child↗
PubMed1983

[Thrombotic microangiopathy and its ocular manifestations: an unusual complication of bone marrow graft].

The clinico-pathological aspect of an unusual case of thrombotic microangiopathy (M.A.T.) is reported in acute leukemia one year after bone marrow graft. The patient was first seen complaining of blurred vision in both eyes. Ocular findings included choriocapillaris and retinal vascular occlusions, resulting in bullous retinal detachments, massive retinal exudation and cystoid macular edema. The relationship between M.A.T. and bone marrow grafting is discussed with respect to the immunological disorders or graft-versus-host reaction and the role of irradiation.

Adult↗
PubMed1983

The induction of retinal detachment.

The induction of retinal detachment is dependent upon several factors whose relative importance remains controversial. These factors are retinal breaks, often associated with vitreous traction, inertial forces and changes in chorioretinal adhesion. Retinal breaks may be classified as holes, tears and dialyses. The relation to the vitreous base is an important prognostic indicator. Once a retinal break has occurred, inertial forces disturb the normal vitreo-retinal association. At that point, the development of a clinical detachment also depends upon loosening of the normal chorioretinal adhesion. Myopia and aphakia are important predisposing factors. The presence of preretinal membranes is a precipitating factor for recurrent retinal detachment. The high success rate of current surgical techniques (85 per cent) is mainly related to a better understanding of the mechanisms leading to retinal detachment.

Adhesiveness↗
PubMed1983

[Retinal phacomas. Apropos of 10 cases of astrocytoma].

Clinical and angiographic findings in 10 cases of retinal astrocytomas seen at the Clinique Ophtalmologique de Créteil are described. Classical features concerning onset of the disease, clinical aspects, and evolution of these tumors are confirmed. Some atypical findings are reported, including the marked proportion of isolated astrocytomas unrelated to phacomatosis, and the high frequency of complications of these lesions, usually considered to be stable.

Adolescent↗
PubMed1983

[Diffuse retinal epitheliopathy and central serous chorioretinopathy].

Follow-up examinations were conducted in 27 patients (51 eyes) affected by diffuse retinal pigment epitheliopathy (D.R.P.E.), over an average period of 37 months. This disease associates multiple subretinal foci of leakage resulting in retinal serous detachments (R.S.D.), often widespread alterations in retinal pigment epithelium, and frequent small serous detachments of retinal pigment epithelium. The course is chronic and recurrence of subretinal leakage is common. Involvement of macular pigment results in poor long-term visual prognosis. Features of these patients were compared with those of 138 patients affected by central serous choroidopathy (C.S.C.). Both D.R.E.P. and C.S.C. are more frequent in males, and demonstrate subretinal leakages and transient retinal serous detachments. Nevertheless, numerous data differentiate these two diseases, D.R.P.E. being detected at a later age (49 years) than C.S.C. (39 years). Bilaterality of the affection is more frequent in D.R.E.P. (88 p. cent) while serous detachment is less frequent in D.R.P.E. (31 p. cent) than in C.S.C. (82 p. cent). Small foci of subretinal leakage are present in both diseases but they are frequently multiple, scattered, extra-macular and mainly peripapillary in D.R.P.E.; they are chronic or recurrent and are present usually in an area of pigment epithelium depigmentation. These changes are often vertically oriented downwards towards the inferior periphery of the fundus. In D.R.P.E. there are frequently visual fields defects (70,5 p. cent) corresponding to the area of pigmentary involvement, dyschromatopsy (64 p. cent) and E.O.G. abnormalities (75 p. cent). D.R.P.E. and C.S.C. are two closely related diseases but they differ by the extent and diversity of the pigment epithelium lesions functional impairment, and visual prognosis. Photocoagulation of leaking spots resulting in macular detachment appears to be justified as in C.S.C. Long-term prognosis depends on the degree of extension of pigmentary changes into the macular area.

Adult↗
PubMed1982

Choroidal ischemia.

Nine patients, seven women and two men, ranging in age from 21 to 86 years, had generalized vascular disease and significant deficits in choroidal perfusion but no retinal vascular changes. Because these perfusion abnormalities can be identified only by fluorescein angiography and the fundus appears to be normal, choroidal ischemia may be more common than has been realized. Infarction of the choroid, retinal pigment epithelium, and outer retina are usually unassociated with retinal detachment; even ischemia severe enough to induce retinal detachment seldom produces significant atrophy.

Adult↗