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Biomedical subjects

A C Bird

Publications and source records attributed to A C Bird.

At least 253 records · Page 14Linked to original sources
PubMed1987

The surgical management of uveal effusion syndrome.

Vortex vein decompression and/or partial thickness sclerectomies were performed on 6 eyes of 4 patients with uveal effusion syndrome. Vortex vein decompression was undertaken in 3 eyes and was followed by retinal re-attachment in two. Multiple sclerectomies were undertaken in 4 eyes of 3 patients; an initial reduction of sub-retinal fluid occurred in all eyes and retinal re-attachment followed in two. There were no complications following the procedure. The response to surgery in these eyes suggests that the approach is justified and provides further evidence that a scleral abnormality is the underlying cause of uveal effusion syndrome.

Adult↗
PubMed1987

Retinal dysfunction in central serous retinopathy.

Patients with acute and chronic central serous retinopathy (CSR) were studied by psychophysical and photochemical means to establish the extent of visual depression and to investigate the basis of rod dysfunction in this disorder. In acute disease with serous detachment of the retina, the loss of sensitivity attains 3 log units and parallels the height of retinal elevation as does its recovery with resolution of the episode. Immediately after resolution, there is a residual 0.5 log unit threshold elevation. In chronic disease, marked loss of function exists over areas of abnormal retinal pigment epithelium in the absence of clinically detectable serous detachment. Although rhodopsin levels are low in both acute and chronic CSR, this relative lack of visual pigment does not totally account for the functional deficits in either situation.

Fluorescein Angiography↗
PubMed1987

Retinal venous sheathing in optic neuritis. Its significance for the pathogenesis of multiple sclerosis.

A systematic study of the frequency of retinal vascular abnormalities and cells in the media has been made in 50 patients presenting with acute optic neuritis. Abnormalities were found in 14 (fluorescein leakage in 10, perivenous sheathing in 6, cells in the vitreous in 6 and in the anterior chamber in 4; in 2 the cells in the media were seen without vascular changes). After a mean follow up of 3.5 years multiple sclerosis (MS) had developed in 8/14 patients with vascular abnormalities and/or evidence of inflammation and in 5/32 without; the difference is significant (P less than 0.02). The occurrence of perivenular abnormalities in a region free of myelin and oligodendrocytes provides evidence that the vascular changes in MS can occur independently of contiguous demyelination, and may be the primary event in the formation of a new lesion.

Adolescent↗
PubMed1987

Retinal vascular abnormalities in facioscapulohumeral muscular dystrophy. A general association with genetic and therapeutic implications.

Because of occasional reports of exudative retinal detachment with facioscapulohumeral muscular dystrophy (FSH) and deafness, we sought to determine by fluorescein angiography whether there is any general relationship between FSH muscular dystrophy and retinal vascular disease. Peripheral retinal capillary abnormalities, comprising telangiectasis, closure, leakage and microaneurysm formation, were demonstrated by angiography in 56 out of 75 individuals with clinical or genetic evidence of FSH. Only 3 patients had relevant ophthalmoscopic abnormalities of the posterior pole and in only 1 was there consequent visual loss. This study included one FSH family in which the propositus was treated for exudative retinopathy and 13 other subjects had telangiectasis, and 8 cases (including 3 parents of apparently 'sporadic' FSH cases) in which fluorescein angiography confirmed the abnormal genotype, even though clinical examination of skeletal muscle revealed no clear abnormality. There was no correlation between the severity of the muscle disease and the extent of the retinal vascular abnormality. Visual complications of telangiectasis, although rare, may present early in life and before there is overt evidence of muscle disease. Since visual loss may be preventable, ophthalmic examination should be undertaken on infants at risk of having the abnormal gene. The findings support the hypothesis that retinal capillary abnormalities are an integral part of the FSH muscular dystrophy syndrome and raise the question as to whether analogous capillary abnormalities could be implicated in the pathogenesis of FSH muscle disease.

Adolescent↗
PubMed1987

Ocular findings in a double-blind study of ivermectin versus diethylcarbamazine versus placebo in the treatment of onchocerciasis.

The effect of ivermectin, a new microfilaricide, was assessed in a double blind trial against diethylcarbamazine citrate (DEC) and placebo. Fifty-nine adult males with moderate to heavy infection with Onchocerca volvulus and with eye involvement were recruited from an area under Onchocerciasis Control Programme (OCP) vector control in Northern Ghana. They were randomly assigned to an eight-day treatment with ivermectin as a single dose of 12 mg on day 1 followed by placebo for the remaining seven days, or DEC, total dose 1.3 g, or placebo, and ophthalmological review was undertaken over a period of one year. DEC acted quickly to eliminate microfilariae from the eye and was associated with reactive ocular changes and in a few cases functional deficit. Ivermectin eliminated microfilariae slowly from the anterior chamber of the eye over a period of six months. The ocular inflammatory reaction was minimal and no functional deficit occurred. It is postulated that the observed slow action of ivermectin on the eye may be attributed in part to its instability to cross the blood-aqueous humour barrier because of its molecular size as a macrocyclic lactone causing microfilariae to leave the eye gradually along a newly created gradient. Ivermectin is an effective microfilaricide with minimal ocular adverse effect and could therefore be suitable for widespread application without strict supervision.

Adolescent↗
PubMed1987

Linkage relationships between X-linked retinitis pigmentosa and nine short-arm markers: exclusion of the disease locus from Xp21 and localization to between DXS7 and DXS14.

Linkage data between X-linked retinitis pigmentosa (XLRP) and nine X-chromosomal markers are reported. To test the assignment of XLRP to the Xp21 region (as considered at Human Gene Mapping 8), an analysis of XLRP and six markers flanking this region was undertaken. The XLRP locus was found to be excluded from the chromosome distal to ornithine transcarbamylase (OTC) (P = 6.5 X 10(-5]. Further data were accumulated with three more probes proximal to DXS7 (L1.28), the closest linked probe. Multipoint analysis of these data suggests a posterior probability of .94 that XLRP is proximal to DXS7 (L1.28), which has been mapped to the region Xp11.3.

Chromosome Mapping↗
PubMed1986

Genetic linkage between X-linked retinitis pigmentosa and DNA probe DXS7 (L1.28): further linkage data, heterogeneity testing, and risk estimation.

Further linkage data relating X-linked retinitis pigmentosa and DNA probe DXS7 (L1.28) is presented in this paper. The current mean estimate of the recombination fraction (theta) including this and all published data, is 0.09, with confidence limits 0.04 to 0.17 (maximum Lod score of 14.01 at a theta of 0.08). There is no evidence for heterogeneity of recombination fraction between the 13 families for which data are available. However, it is argued that heterogeneity should be assumed to exist for the purposes of risk estimation. Mean estimates and variances of risk are calculated for hypothetical families each with different linkage data. In families in which no recombination has been observed, the mean and variance of risk are sufficiently small for the clinical use of this probe to be acceptable to many.

DNA↗
PubMed1986

Retinitis pigmentosa and retinal neovascularization.

Four patients with retinitis pigmentosa and either disc or peripheral retinal neovascularization with recurrent vitreous hemorrhage are described. One patient with peripheral retinal neovascularization also had rubeosis and neovascular glaucoma. The effects of relative hyperoxia on the retinal microcirculation in retinitis pigmentosa as well as intraocular inflammation may account for such changes. Laser photocoagulation appears effective in preventing vitreous hemorrhage in these patients, but systemic administration of corticosteroids did not cause the new vessels to regress.

Adult↗
PubMed1986

Paramacular telangiectasis.

Forty six patients with paramacular retinal telangiectasis were reviewed; unilateral telangiectasis was present in 26 and bilateral disease was present in 20. Patients with unilateral macular telangiectasis had the more extensive vascular involvement associated with exudation and were more likely to have peripheral telangiectasis. Bilateral macular telangiectasis was associated with pigment epithelial changes and sub-retinal scars. Visual acuity was mildly reduced in the majority of patients; severe loss of vision was most frequent in patients with bilateral macular disease. The evolution of vascular changes was very slow and only 5 patients lost vision of two lines or more during an average period of 40 months. The high incidence of peripheral changes in unilaterally involved patients implies the possibility of a primary defect of the retinal vessels in these patients. There is evidence to suggest that there may be a primary defect of the retinal pigment epithelium in some patients with bilateral involvement.

Adult↗
PubMed1986

Optic disc swelling in sympathetic ophthalmitis and Harada's disease.

In sympathetic ophthalmitis and Harada's disease the fundus appearance is characterised by pale areas of elevated retina associated with a diffuse choroidal abnormality on fluorescein angiography. Optic disc swelling, though constant, is rarely prominent. Four patients, one with sympathetic ophthalmitis and three with Harada's disease, are described, in whom optic disc swelling with visual loss was the predominent sign at one stage of the disease.

Adult↗
PubMed1985

Retinal telangiectasis in facioscapulohumeral muscular dystrophy with deafness.

A 22-year-old patient with newly diagnosed facioscapulohumeral (FSH) muscular dystrophy had a macular lesion in her right eye and poor central vision, which had been present since early childhood. Fluorescein angiographic examination revealed bilateral peripheral vessel closure, peripheral retinal telangiectasis, and hyperfluorescence in both foveae. This widespread vascular abnormality was deemed responsible for her macular disease. Her mother, brother, and sister, all of whom are affected by varying degrees of FSH muscular dystrophy and clinical deafness, also have abnormal retinal vasculature, as determined by fluorescein angiography. However, none had related visual symptoms and two showed no ophthalmoscopic evidence of vascular abnormalities. In young patients with unexplained retinal vascular lesions, the diagnosis of FSH muscular dystrophy should be considered. Similarly, young patients with FSH muscular dystrophy should be examined for sight-threatening and potentially treatable vascular retinopathy.

Adult↗
PubMed1985

A clinical, psychophysical, and electroretinographic survey of patients with autosomal dominant retinitis pigmentosa.

We have surveyed 104 patients (44 families) with autosomal dominant retinitis pigmentosa. The range of the survey includes clinical history, ocular examination, documentation of genetic history, Goldmann kinetic perimetry with IV/4 and I/4 white targets, two-colour static perimetry, and scotopic and photopic electroretinography. Comparison of interfamilial and intrafamilial patterns in the static perimetry data strongly suggests there may be at least two genetic subgroups within the disease characterised by the pattern of loss of rod function: in subgroup D (13 patients, 4 families) this is diffuse and severe, while in subgroup R (28 patients, 13 families) it is regional. In both D and R loss of cone function is regional, and in R it coincides with loss of rod function. In D patients the rod electroretinogram is absent; in all but two R cases it is present and usually substantial. All D patients were aware of night blindness before the age of 10, but most R patients not until after the age of 20. Many of the patients could not be classified because their disease was so advanced. The effect of disease duration on visual acuity and visual field area is described for all patients.

Adolescent↗
PubMed1985

Retinal pigment epithelial detachments in the elderly: classification and outcome.

Sixty-four eyes of 57 elderly patients with pigment epithelial detachments (PEDs) were studied with the aim of describing their morphological features and identifying prognostic factors. They were classified into four groups according to the following characteristics: early fluorescence, late fluorescence, shallow detachment with limited fluorescence ('drusen type'), irregular fluorescence. The following conclusions were drawn: 30% developed demonstrable subretinal new vessels; all groups except the drusen type were susceptible, the irregular group being particularly prone. 10% developed retinal pigment epithelial tears, and these occurred almost exclusively in the slow fluorescent group. Flattening of PEDs was a feature of drusen type and early fluorescent groups. Most patients lost vision. RPE tears occurred within a few months of presentation with immediate loss of vision; likewise rapid loss of vision followed the development of demonstrable new vessels, though not necessarily in those with changes thought to imply the presence of new vessels. Flattening after prolonged detachment was associated with pigment epithelial atrophy and invariable loss of vision. Visual acuity was maintained consistently only in those eyes with persistent detachment.

Aged↗
PubMed1985

Recurrent visual loss in homozygous sickle cell disease.

In sickle cell retinopathy vascular involvement is most frequently recognised at the retinal periphery, but obstruction of perimacular arterioles and of major retinal vessels may also occur. This report describes a patient with homozygous sickle cell (SS) disease with recurrent occlusion of major retinal vessels associated with recurring transient impairment of visual function.

Adult↗