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Biomedical subjects

A C Bird

Publications and source records attributed to A C Bird.

At least 289 records · Page 16Linked to original sources
PubMed1982

Sickle cell retinopathy in young children in Jamaica.

Ophthalmological examinations were performed on 59 of the 74 (80%) children with homozygous sickle cell (SS) disease and on 37 of the 54 (69%) children with sickle cell-haemoglobin C (SC) disease, aged 5-7.5 years, within the cohort study of sickle cell disease. Arteriolar sheathing was the commonest retinal vessel abnormality, occurring in 30/59 (51%) SS children and in 11/37 (30%) SC children. Peripheral arteriolar closure was observed in 14 (24%) SS children and in 6 (16%) SC children. Arteriovenous anastomoses were seen in 3 children, but proliferative retinopathy was not identified. Capillary changes often occurred in patients without confluent closure, suggesting that complex remodelling of the capillary bed may precede retinal non-perfusion. Discrete retinal patches similar to schisis cavities resulting intraretinal haemorrhages were found in 22 (37%) SS children and in 9 (24%) SC children, but haemorrhages were observed in only 2 patients (1 SS, 1 SC). Vitreous opacities were common and were generally associated with retinal vessel disease. Retinal changes were consistently more common in children with SS disease, though the differences failed to reach statistical significance. The prevalence of peripheral vascular closure and retinal patches showed a significant upward trend with age. These observations contrast with the greater prevalence of proliferative retinopathy characterising SC disease in adults.

Anemia, Sickle Cell↗
PubMed1981

Sorsby's pseudoinflammatory macular dystrophy.

Forty-three additional members of a family described originally by Sorsby and Mason have been examined in order to typify pseudoinflammatory macular dystrophy more accurately. Six new affected members were identified by history alone and a further 7 were examined. Vision is lost from disciform macular degeneration generally during the 5th decade of life. Thereafter peripheral degeneration occurs in some affected members. Before loss of vision the fundus changes include fine drusen-like deposits at the level of Bruch's membrane, angioid streaks, and plaque-like deposits of yellow subretinal material in the macular region. These changes are different from those seen in dominant drusen.

Adult↗
PubMed1981

The dark choroid in posterior retinal dystrophies.

Many patients with heredomacular degeneration exhibit a peculiar fluorescein angiographic finding of absence of the normal background fluorescence (a dark choroid). The cause of this is unknown but may relate to the deposition of an abnormal material in the retinal pigment epithelial cells. The finding does not correlate with severity or duration of disease but is more frequent in patients with flecks. The finding may be useful in subdividing heredomacular degenerations into more specific disease groups.

Capillaries↗
PubMed1981

Tears of detached retinal pigment epithelium.

Ripping of detached pigment epithelium appears to be a common sight-threatening complication of pigment epithelial detachments and occurs at the junction of the detachment and flat pigment epithelium. The characteristics of the detachment prior to the rip suggest that the tear occurs in pigment epithelium which is detached without its basement membrane. The tear is followed by retraction of the pigment epithelium, revealing bare Bruch's membrane. The defect may remain apparently unaltered, or may be recovered by normal looking pigment epithelium, but most commonly is replaced by a fibrous plaque. Most patients had a profound reduction in visual acuity.

Aged↗
PubMed1980

PIgment epithelial diseases with abnormal choroidal perfusion.

Sixteen patients, seen during the first week of their disease, had swelling of the retinal pigment epithelium and angiographic evidence of a widespread abnormality of choroidal filling. The patients fell into three groups: In Group 1 there were multifocal pigment epithelial lesions identical to those of acute posterior multifocal placoid pigment epitheliopathy. In Group 2 the pigment epithelial lesions were confluent. The retina was not detached in either of the these groups. In Group 3, multifocal lesions of the pigment epithelium were associated with retinal detachment. We postulated that all patients had diffuse choroidal hypoperfusion and focal pigment epithelial infarct which, in turn, may have been caused by a variety of basic disorders. We detected no relevant systemic abnormalities in any of the patients.

Adolescent↗
PubMed1980

Autosomal dominant exudative vitreoretinopathy.

Twelve affected members from 3 families with autosomal dominant exudative vitreouretinopathy were examined, and the following conclusions were drawn: (1) There is great variability in the phenotypic expression of the abnormal gene, such that many patients have very mild disease which can be detected with certainty only by fluorescein angiography. (2) Gene penetrance is close to 100%. (3) Progress of fundus changes and visual threat is rare after 20 years of age.

Adolescent↗
PubMed1980

Changes in visual function and in the posterior segment of the eye during treatment of onchocerciasis with diethylcarbamazine citrate.

Eighteen patients, moderately to heavily infected with onchocerciasis, were treated with a standard course of diethylcarbamazine citrate (DEC-C). In addition to the well recognised systemic reactions to treatment, the following ocular changes occurred during therapy: (1) Transient pigment epithelial lesions were detected in 7 patients by fluorescein angiography. (2) Optic disc leakage, as shown by fluorescein angiography, developed in 9 patients, and increase of pre-existing leakage was demonstrated in 3 further patients. (3) Visual field loss was documented in 5 patients. These observations have grave implications for DEC-C therapy in onchocerciasis. They emphasise the need for great caution in its use in the treatment of onchocerciasis in heavily infected patients and for close supervision of ocular function during therapy.

Adolescent↗
PubMed1979

A comparative histopathological study of argon and krypton laser irradiations of the human retina.

A series of comparative exposures to both argon and krypton lasers have been made at 3 locations in a human retina--the fovea, the macula, and intraretinal vessels. In the fovea argon irradiations resulted in damage to both the inner and outer retinal layers as a result of absorption within the pigment epithelium and the macular pigment, while krypton exposures damaged the outer retina and the choroid. In the macula both systems resulted in damage to the outer retina, and again sufficient krypton radiation passed into the choroid to induce blood vessel occlusion, haemorrhage, and oedema. When intraretinal vessels were irradiated, only with argon was sufficient energy absorbed within the vessels to damage them or their surroundings in the inner retina. The implications of these findings are discussed in relation to the therapeutic uses of lasers.

Argon↗
PubMed1979

Photocoagulation of disciform macular lesions with krypton laser.

Ten vascular disciform mucular lesions were treated by krypton laser photocoagulation. In 8 the lesion resolved after therapy, and in 7 the retina remained flat for 6 months. On those patients treated successfully 6 had a visual acuity of 6/12 or better. The morphology of the laser lesion differed from that of the argon lesion in that there is no evidence of thermal coagulation of the inner retina near the foveola.

Adult↗
PubMed1979

Senile disciform macular degeneration: features indicating suitability for photocoagulation.

During a 1-year period 398 new patients were seen with disciform macular degeneration (530 eyes). The lesions were studied retrospectively, and those in which the neovascular tissue did not underlie the fovea, and therefore were treatable, were identified. The following conclusions were drawn: (1) Treatment is possible in most patients with good acuity and few with poor acuity. (2) Treatment is possible in a large proportion of patients with a short history and few with a long history of visual loss. (3) As many as 50% of all patients with senile disciform macular degeneration may be amenable to treatment if seen early enough in the course of their disease. (4) Over one-third of eyes with lesions that are untreated have a visual acuity of 6/60 or better 3 years after the onset of symptoms. (5) If a controlled trial proves that treatment is beneficial, these results emphasise the need for rapid referral and show that these patients will generate a large additional clinical load.

Humans↗
PubMed1979

Experimental retinal branch vein occlusion in rhesus monkeys. I. Clinical appearances.

Branch and hemisphere vein occlusion were produced in rhesus monkeys by argon laser photocoagulation. The following observations were made: (1) Immediately after occlusion there was venous dilatation, delayed filling of the artery, delayed drainage by the occluded vein, and capillary leakage. (2) Two patterns of evolution were identified within the first week. In some animals the fundus changes resolved and the retina returned to normal, while in others there was progressive retinal capillary closure. (3) Those animals destined to have capillary closure had diffuse or cluster retinal haemorrhages at 24 hours. (4) Capillary closure took place over 1 week and was usually complete over large areas of retina. (5) Retinal atrophy and major vessel changes occurred over several weeks. (6) Retinal revascularisation occurred in those areas of closure, though this was often limited. It was concluded that the early changes mimicked those seen in human retinal vein occlusion, though persistent retinal oedema and preretinal neovascularisation were not identified.

Animals↗
PubMed1978

Retinitis pigmentosa and retinal oedema.

Twenty-five patients with retinitis pigmentosa and retinal leakage were investigated. Oedema was present in dominant and X-linked inherited disease and is likely to be present in recessive disease as well. We suggest that this might be a general response seen in many types of tapeto-retinal degeneration to actively degenerating photoreceptors or pigment epithelium.

Adult↗