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Biomedical subjects

H Hamard

Publications and source records attributed to H Hamard.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Unexplained bilateral optic disk edema. So-called idiopathic intracranial hypertension of drug origin should be suspected].

In 2 clinical cases of bilateral optic disk oedema, the optic disk oedema was part of a so-called benign, or rather idiopathic, intracranial hypertension. Aetiological investigations were unable to detect any intracranial or systemic anomaly, except the fact that both patients had been on a long-term treatment. The first, a 35-year-old man, was taking Roaccutane (isotretinoin) for acne, for at least 5 years, Supradyne (containing vitamin A) minimum 1 pill per day. The second patient, aged 16 years, had also been treated for acne with Roaccutane and Mynocine (minocyclin) for several months. Minocyclin and vitamin A, contained in these substances, are likely to have induced the idiopathic intracranial hypertension, and consequently the optic disk oedema. Indeed, discontinuing the treatment and rachicentesis led to a significant resolution of symptoms. A good history of the clinical cases thus remains a key-element in the process of diagnosis-making and should be strictly conducted in cases with bilateral optic disk oedema, particularly when seen in young patients.

Adolescent↗
PubMed1994

Blood flow rate in the microvasculature of the optic nerve head in primary open angle glaucoma. A new approach.

In order to evaluate the optic nerve head perfusion in patients with primary open-angle glaucoma (POAG), we measured the velocity of the red blood cells (RBCs) in the capillaries of the optic nerve head with a laser-Doppler velocimeter and evaluated the blood viscosity by determining the capacity of the RBCs to disaggregate with an erythroaggregameter. Our results showed that in POAG patients optic nerve blood velocity was reduced and that the aggregability of the RBCs was increased. The two parameters were not significantly correlated, possibly because of local papillary autoregulation and anatomical variability in the papilla vessels. These two factors could explain why the same rheological anomaly in two subjects could lead to different responses in blood velocity. The RBC hyperaggregability cannot be explained by quantitative modifications of the plasma proteins. Modifications in the membrane of the RBCs could indeed be responsible for hyperaggregability, since our data suggest that deformability of the RBCs is impaired in glaucoma.

Adult↗
PubMed1994

Optic nerve head blood flow using a laser Doppler velocimeter and haemorheology in primary open angle glaucoma and normal pressure glaucoma.

Optic disc blood flow velocity was measured in healthy patients, those with primary open angle glaucoma (POAG), and patients with normal pressure glaucoma (NPG). The velocity of the red blood cells (RBCs) in the capillaries of the optic nerve head (ONH) has been measured with a laser Doppler velocimeter (LDV), and blood viscosity has been evaluated notably by determining the aggregability of the RBCs with an erythroaggregameter. Our results in POAG patients and NPG patients showed that their optic nerve blood flow velocity was reduced and that the aggregability of the RBCs was increased. The hyperaggregability of the erythrocytes is responsible for the increase of the local viscosity in the papillary capillary network. These haemodynamic modifications observed in patients with glaucoma support the hypothesis of a vasogenic mechanism that could impair the optic nerve in glaucoma patients.

Adult↗
PubMed1994

[Prevention of postoperative inverse astigmatism during radial keratotomy].

Seventy eight patients (156 eyes) were treated by radial keratotomy. Patients with spherical axial myopia were selected (including 39% of physiological astigmatism cases). After radial conventional technique the against-the-rule astigmatism > 1.0 D is 31.6% and between 1.0 and 2.0 D is 3.4% versus 0.6% (< 1.0 D) and 0.1% (1.0-2.0 D) with the modified technique. To decrease the frequency of the against-the-rule postoperative astigmatism after RK procedure we performed 1 or 2 vertical additional flag-incisions on the horizontal meridian to counteract the effect of the corneal oedema on the superior incisions.

Astigmatism↗
PubMed1994

[Ocular myasthenia: an etiology to consider in unexplained oculomotor paralysis].

Three cases of ocular myasthenia gravis were observed. The first patient, a 74-year-old man was found to have complete left ophthalmoplegia and ptosis unchanged at examination on month after onset. The second patient, a 42-year-old man, developed incomplete right ophthalmoplegia with pseudoanterior internuclearis ophthalmoplegia, then ptosis two days later. The third patient, a 70-year-old man, presented with sudden onset complete right palsy of the third nerve. Diabetes mellitus or intra-cranial lesions were suspected in all three patients although laboratory tests, tomodensitometry, nuclear magnetic resonance imaging, or arteriography gave no confirmation. Ptosis was relieved and eye movement was improved after the intravenous edrophonium test, but electromyography was negative. The three patients were treated with anticholinesterase agents and showed unequivocal improvement. The second patient underwent thymectomy. Clinicians should inform patients of the contraindications of drugs in this disease. The diagnosis of pure oculomotor forms of myasthenia gravis is sometimes difficult to establish and should be suspected in cases of unexplained oculomotor palsy.

Adult↗
PubMed1994

[Leber's idiopathic stellate neuroretinitis. Apropos of 9 cases].

Leber's optic neuroretinitis is a particular form of optic neuropathy characterized by swelling of the optic disc and a stellate pattern of exsudative deposits in the macula. It occurs most often in healthy young subjects who have acute monolateral visual loss, often preceded by presumed viral illness. The etiology is unknown and viral infection has been suggested in the pathogenesis of this condition. The prognosis for visual recovery is reported to be excellent, but late visual sequelae have been described: loss of vision or visual field loss. This entity should be recognized and distinguished from more serious diseases causing septic neuroretinitis or papillitis.

Adolescent↗
PubMed1993

[Cataract and implantation in the vitrectomized eyes].

Cataract is a frequent complication of vitreous surgery after some months or years. In these cases cataract extraction is somewhat difficult. We performed cataract surgery with implantation in 38 eyes from 37 patients between 1986 and 1991. Twenty patients underwent vitreous or vitreoretinal surgery with or without internal tamponade by gas, 17 underwent silicone oil tamponade and silicone oil removal, prior to cataract surgery. Timing of surgery, number of surgical procedures and complications previous to cataract surgery are detailed in the paper. Cataract extraction was extracapsular in 7 cases, intracapsular in 6 cases; phako was performed in 24 cases and phacophagy in one case. A posterior IOL was inserted in 31 cases, an anterior chamber IOL in 7 cases. Anatomical and visual results were satisfying. Visual acuity improved postoperatively in 29 cases (up to 20/20 in 4 cases), was unchanged in 6 cases, decreased in 3 cases. Among these, loss of vision occurred in 5 cases due to retinal detachment or redetachment. For anatomical reasons, lack of vitreous support and the frequent zonular weakness of these eyes, account for surgical difficulties. Thus, phakoemulsification appears the best way to manage cataract in vitrectomized eyes.

Adult↗
PubMed1992

[Hemo-rheology of glaucomatous neuropathy].

The vascular participation to the optic nerve pathogenesis has been contradicted. The red blood cell velocity in the optic nerve capillary with a laser Doppler velocimeter, an atraumatic and reliable method, and the aggregability was determined with an erythroaggregameter to know whether an erythrocyte hyperaggregability could slow down the optic nerve blood flow as it has been previously demonstrated in an experimental study. The experiment on the open angle glaucoma patients showed that their optic nerve blood flow was reduced, and their erythrocyte aggregability significantly increased. The two parameters were not significantly correlated, certainly because of a local papillary autoregulation and of the papilla vessels variability, those two factors could modulate the blood flow response to blood qualitative changes. The erythrocyte hyperaggregability could be explained by erythrocyte membrane modifications that could agree with the glaucoma heredity.

Animals↗
PubMed1990

[Cyclodiathermy: is it effective in the treatment of glaucoma?].

The authors describe the non penetrating technique of cyclodiathermy in the treatment of different types of glaucoma and publish the results and the complications of the application of this technique on thirty three eyes among their patients. These eyes included congenital glaucoma (8 eyes), aphakic glaucoma (5 eyes), after silicone surgery (5 eyes), neovascular glaucoma (4 eyes), traumatic glaucoma (4 eyes), secondary glaucoma (3 eyes), Sturge-Weber-Krabbe (2 eyes) and open angle glaucoma (2 eyes). Their study with a mean follow up of 2.5 years shows an overall success rate of 60%. The success is defined as an ocular tension less than or equal to 22 mmHg in the absence of serious complications. All the encountered complications are mentioned. Phtysis occurred in not more than 3% of cases (1 eye). They establish a comparison with the published results and complications of the other cyclodestructive procedures: Sonocare, transcleral laser Yag, transcleral laser Ruby and cyclocryotherapy. This comparison does not prove the superiority of these other procedures with regard to the non penetrating cyclodiathermy. They conclude that this non penetrating cyclodiathermy is a non expensive procedure which still have its good therapeutic value.

Electrocoagulation↗
PubMed1990

[Diagnostic procedures in optic neuropathies].

Functional disturbance and ophthalmoscopic feature are the most important parameters to diagnose optic neuropathy. Swelling of the optic disc is produced by 2 aetiologies: inflammation and ischaemia. The most frequent cause of retrobulbar neuritis remains multiple sclerosis.

Fluorescein Angiography↗
PubMed1990

[Toxicity of ethylene oxide on the crystalline lense in an occupational milieu. Difficulty of epidemiologic surveys of cataract].

Ethylene oxide is a sterilizing gas for heat-sensitive materials. Eight cases of subcapsular cataract were attributed to this compound from 1982 to 1985. This epidemiological study was conducted in 55 persons to determine the prevalence of lens opacities and cataracts in workers exposed to this gas. The 21 persons of more than 45 years of age were then compared to 16 non-exposed persons matched for age and gender. Lens opacities (independently of visual acuity) were observed in 19 of the 55 exposed. Among exposed and non-exposed persons of more than 45 years of age, there were no significantly differences with regard to the following characteristics of lens opacities: prevalence (13 in the 21 exposed; 10 in the 16 non-exposed), distribution of the localisations, morphology and importance of the cortical opacities. No link was found between the characteristics of the lens opacities and the characteristics of the exposure: habitual exposure and accidental overexposures. For cataracts, defined by the association of lens opacities and a visual acuity less than 20/25 (this loss not being attributable to another cause), their prevalence differed significantly (p less than 0.05) between the exposed (6 of 21) and the non-exposed (0 of 16). There was no relation between their existence and accidental overexposures. The risk of lens opacification by ethylene oxide, established in cases of massive exposures as previously described, could also exist during chronic exposure to low concentrations, but is to be confirmed by other studies. It could be explained by saturation of the protective mechanisms against alkylating action of this product. This study prompted us to discuss the epidemiological difficulties in studies of cataracts.

Animals↗
PubMed1990

[Effects and complications of Nd YAG laser posterior capsulotomy after ECA + PCI (extracapsular extraction and posterior chamber implantation)].

264 consecutive cases of ECCE are reviewed. In this series 28 cases of Nd YAG laser capsulotomy have been performed. Visual results are excellent: visual acuity is improved in 90% of cases. The rate of complications is low: 1 case of retinal detachment, 2 cases of IOP raise, no clinical CME. Laser therapy is performed when visual acuity decreases, prior to other extra clinical examination.

Aged↗
PubMed1989

[A case of MEWDS. "The multiple evanescent white-dot syndrome"].

A young white man developed acute bilateral visual loss with no previous general illness. Ophthalmoscopic examination showed multiple small yellow-white lesions scattered throughout the posterior poles and mild periphery fundus. There was also fine granularity of two foveal areas and one optic disc margin was blurred. Fluorescein angiography showed early hyperfluorescence of the lesions and late staining of the retinal pigment epithelium. Electrophysiologic abnormalities were transient, asymmetric, more marked in photopic than in scotopic. The origin could be in retinal bipolar cells. These lesions regressed, with return of normal visual function within several weeks. These clinical findings are different from others acute inflammatory diseases primarily involving retinal pigment epithelium and photoreceptors. This aspect is usually described as "multiple evanescent white dot syndrome". The etiology of this syndrome remains unknown with no evidence of systemic disease. A history of flulike illness is rare.

Adult↗
PubMed1988

[Histiocytofibroma of the sclerocorneal limbus].

A case of epibulbar benign fibrous histiocytoma is presented, with an optical microscopic study. A greyish vascularised nodule developed at the corneoscleral limbus in a 65 year-old male. The clinical diagnosis was confirmed by histopathologic evaluation. Complete surgical excision had a curative effect.

Aged↗