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Biomedical subjects

G Chaine

Publications and source records attributed to G Chaine.

At least 73 records · Page 4Linked to original sources
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

[Hypertensive retinopathy].

Retinal blood vessels differ from most other vessels in the body (with the exception of those in the brain) in two important respects. The first is the presence of blood-retinal barriers, best illustrated by fluorescein angiography. The second important difference is that retinal vessels do not have sympathetic innervation and blood flow is modulated by autoregulation mechanisms. In 1939 Keith, Wagener and Barker proposed a classification system for hypertensive retinopathy which was innovative and of prognostic importance at that time. However, the different features of hypertensive and arteriosclerotic vasculopathies are not adequately distinguished by this classification system. Clinical features of accelerated hypertension are retinal haemorrhages, cotton wool-spots, hard exudates, papilloedema and increased vascular permeability. These must be differentiated from features associated with arteriosclerosis which are arteriovenous crossing changes and arterial constriction. The advantages of the Hogan classification system, based up on histopathologic and pathogenetic considerations are discussed. Other retinal vascular diseases associated with hypertension are also mentioned. Such as toxaemia of pregnancy, arterial macroaneurysm and anterior ischaemic optic neuropathy. Retinal branch vein occlusion is rather associated with arteriosclerosis than with hypertension.

Animals↗
PubMed1982

Ophthalmologic abnormalities in the hypereosinophilic syndrome.

Twelve patients with hypereosinophilic syndrome were studied to determine the frequency and type of eye involvement in this systemic disease. Four patients (33%) had visual symptoms, including blurred vision in one or both eyes, and one patient had an episode of complete blindness following cardiac surgery. Five patients (42%) had eye involvement by direct examination, and ten (83%) in fluorescent retinal angiograms. The principal defects noted were occlusions of major retinal vessels, choroidal infarct, and patchy or delayed choroidal filling. As these defects all occurred in patients with other severe systemic complications of the hypereosinophilic syndrome, including cardiologic disease, it is suggested that these lesions were the result of thromboembolic disease and that these patients should receive long-term anticoagulation. It was concluded that eye involvement is a frequent and important feature of the hypereosinophilic syndrome.

Adult↗
PubMed1982

[Effects of anterior chamber perfusion on the rabbit corneal endothelium: a scanning electron microscopy study (author's transl)].

The effects of intraocular irrigating solutions (TC Earle and NaCl 9%) on the rabbit corneal endothelium were evaluated utilizing scanning electron microscopy. Introcular pressure was maintained at 15 or 50 mm Hg. Rate of perfusion was between 50 microliter/min and 2 ml/min. With NaCl 9%, in eyes exposed to high pressure (50 mm Hg) for 2 hours with a rate of 50 microliter/min changes could be detected: rupture of apical junctions and minimal structural changes. Similar lesions appeared with a pressure of 15 mm Hg at a rate of ml/min. With Earle solution, no lesions were seen after 3 hours and minimal changes after 4 hours. Intraocular irrigating solution seems to be more toxic than increased intraocular pressure on the structure of endothelial cells, as seen on scanning electron microscopy. Greater sensitivity of endothelium to perfusion fluid than intraocular pressure probably explains the paradoxical appearance of corneal edema in diseased states, and suggests that endo-ocular surgical procedures require modification.

Animals↗
PubMed1979

[Treatment of diabetic retinopathy with laser photocoagulation (author's transl)].

Laser photocoagulation has changed the visual prognosis of diabetic patients affected by retinopathy. It aims to lower the risk of blindness of diabetic patients. The goal of photocoagulation is to reduce the tissue damage of microangiopathic origin expressed by nonperfusion areas and permeability abnormalities that are responsible for retinal ischemia and oedema respectively. Loss of visual acuity in the diabetic is due mainly to two causes : first, vitreous hemorrhage with its dramatic loss of vision; secondly, macular cystoid oedema, occuring more commonly and with progressive loss of central vision. The efficiency of pan-retinal photocoagulation in reducing the risk of vitreous hemorrhage and consequent blindness in patients with disc or preretinal newly formed vessels, has been ascertained by American and British randomised studies. The indications, technics and results of photocoagulation in non-proliferative diabetic retinopathy are the subject of many studies. Only photocoagulation for macular oedema due to intra-retinal microvascular abnormality has shown to be of benefit.

Diabetic Retinopathy↗
PubMedDate not supplied

[Cost of managing cataracts. Evaluation of traditional hospitalization and ambulatory surgery].

OBJECTIVE: Demonstrate eventual differences and evaluate the medical costs of treatment of a cataract in traditional hospitalisation and out-patient surgical conditions. METHODS: We conducted a study of minimisation costs in 3 ophthalmologic hospital departments. This retrospective study randomly selected the medical files of 250 patients (100 operated in the out-patient surgical department and 150 operated in traditional surgical conditions). Costs were evaluated on direct hospital costs, according to the standard costs method and the method of true costs. RESULTS: The mean total cost of a cataract is of 10,984 F in traditional hospital conditions and of 7,683 F in out-patient surgical conditions. DISCUSSION: In terms of direct hospital costs, treatment of cataracts in out-patient surgery appears more economic compared with traditional surgery. The difference in cost concerned the fixed hospital charges (structures and staff). CONCLUSION: Out-patient surgery will progress in France in the next few years, but traditional hospitalisation will still be required in ophthalmologic practice.

Ambulatory Surgical Procedures↗
PubMedDate not supplied

[Diabetic papillopathy and bilateral anterior ischemic optic neuropathy].

A 16 year old juvenile diabetic presented with a diabetic papillopathy (D.P.). Visual impairment is known to be minimal in D.P. Our patient presented with all clinical features of diabetic papillopathy (disk oedema, massive leakage). Evolution toward poor visual acuity in one eye, and visual field defect in the other eye is unusual. We discuss relationship between D.P. and anterior ischemic optic neuropathy.

Adolescent↗