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Biomedical subjects

P E Cleary

Publications and source records attributed to P E Cleary.

15 recordsLinked to original sources
PubMed1979

Method of production and natural history of experimental posterior penetrating eye injury in the rhesus monkey.

We developed an experimental model for a posterior penetrating eye injury that resulted in traction retinal detachment in 21 rhesus monkey eyes. The standard injury was an incision through the pars plana with vitreous prolapse and incarceration; the wound was then carefully closed with microsurgical techniques. At one to two weeks after injury, detachment of the posterior vitreous occurred and detachment of the retina occurred between seven and 11 weeks. The development of retinal detachment was related to traction on the peripheral retina over the vitreous base; and to the contraction of epiretinal membranes on the peripheral and equatorial retina. Our study supports clinical observations on the importance of blood in the vitreous in the development of vitreous traction and traction retinal detachment after a posterior penetrating injury.

Animals↗
PubMed1979

Histology of wound, vitreous, and retina in experimental posterior penetrating eye injury in the rhesus monkey.

We performed a histologic study to support our clinical observations on the mechanisms responsible for traction retinal detachment after a penetrating injury in the rhesus monkey eye. The monkey eyes (40 eyes; 40 monkeys) were characterized by intraocular fibrosis with the formation of a cyclitic membrane and epiretinal and subretinal membranes. The progression to a fibrous ingrowth from the wound occurred only in eyes with blood in the vitreous. The intravitreal fibroblastic proliferation had its origin mainly from the stroma of the ciliary body and choroid at the wound but probably also from the nonpigmented ciliary epithelium. A fibroblastic response was present within the vitreous as early as four days after injury, and had progressed to form a cyclitic membrane by six weeks. Epiretinal membranes were identified as early as four weeks after injury. They were most prominent over the peripheral retina anterior to the equator. It is likely that they are derived from multiple cellular sources including the fibrous ingrowth from the wound but they were also connected to the surface of the retina by bridges of tissue indicating a glial origin. The subretinal membranes appeared to be derived from both retinal pigment epithelium cells and glial cells.

Animals↗
PubMed1979

Experimental posterior penetrating eye injury in the rabbit. I. Method of production and natural history.

A technique has been developed which produces an experimental posterior penetrating eye injury that reproducibly results in traction retinal detachment in rabbit eyes. The standard injury is an incision through the pars plana with vitreous prolapse and incarceration; the wound is then carefully closed with microsurgical techniques. It appears that blood in the vitreous is an essential factor in the development of vitreous traction and of traction retinal detachment. The model, which has been successfully transferred to Rhesus monkey eyes, is considered useful for further histological, electromicroscopical, electrophysiological, and ultrasound studies of posterior penetrating injuries of the eye. Our immediate goal is to assess in a controlled experiment whether pars plana vitrectomy can interrupt the sequence of events leading to traction retinal detachment after a posterior penetrating injury.

Animals↗
PubMed1979

Experimental posterior penetrating eye injury in the rabbit. II. Histology of wound, vitreous, and retina.

The histological findings of the wound, the vitreous, and the retina in the rabbit eye with experimental posterior penetrating injury are described. Wound healing had just begun at 3 days after injury and was well established by 9 to 12 days. It involved proliferation of cells from the episclera and from the choroid. The progression to a fibrous ingrowth from the wound occurred only in eyes with blood in the vitreous. The intravitreal fibroblastic proliferation had begen at 6 days after injury and seemed to be derived from the choroid, the nonpigmented ciliary epithelium and, posteriorly, from the optic nervehead. During the development of retinal detachment the configuration of the peripheral and posterior retina, together with the orientation of vitreous strands, suggested the presence of vitreous traction. We postulate that the presence of contractile fibroblasts (myofibroblasts) in the vitreous may provide the mechanism for vitreous traction. The retinal detachments were also characterised by epiretinal and subretinal membranes, but these were not prominent. The end-stage appearance of a soft, shrunken eye with cyclitic membrane formation and retinal detachment resembles the outcome in many human eyes after severe penetrating injuries.

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↗
PubMed1978

Macular abnormalities in the reattached retina.

Sixty-six patients in whom the macula was detached before surgery were observed for at least 1 year after retinal reattachment. Macular abnormalities were recognised clinically in most patients with severely reduced vision. Failure of retinal receptor regeneration or receptor misalignment may account for visual reduction in a minority of patients but may be less important as a cause of reduced visual acuity than was previously supposed. This study confirms that the visual prognosis is related to the duration of the detachment before surgery, and patients with a macular detachment for 2 months or longer are likely to suffer persistently reduced vision.

Fluorescein Angiography↗
PubMed1978

Posterior perforating eye injury. Experimental animal model.

A technique has been developed which produces an experimental posterior perforating eye injury, that reproducibly results in traction retinal detachment. The standard injury is an incision through the pars plana with vitreous prolapse and incarceration; the wound is then carefully closed with microsurgical techniques. It appears that blood in the vitreous is an essential factor in the development of vitreous traction and of traction retinal detachment. The model is considered useful for further histological, electron microscopic, electrophysiological, and ultrasonic studies of posterior perforating eye injuries. In a controlled experiment, it will be possible to assess whether pars plana vitrectomy can interrupt the sequence of events leading to traction retinal detachment after posterior perforating injury.

Animals↗
PubMed1977

Macular morphology in the re-attached retina.

A sequential study of the macula using biomicroscopy and fluorescein angiography in patients who had undergone successful retinal re-attachment procedures is reported. The purpose of this study is to identify the morphological changes which occur at the macula following retinal re-attachment surgery, and to relate these changes to the post-operative visual function.

Humans↗
PubMed1976

Retinal vascular changes in congenital hypertrophy of the retinal pigment epithelium.

The overlying retinal blood vessels were abnormal in five cases of congenital hypertrophy of the retinal pigment epithelium. This illustrated the well-recognized association between outer retinal degeneration and obliteration of the overlying retinal vasculature. The proposed pathophysiological mechanisms, however, seem inadequate to explain completely the morphological changes of the retinal blood vessels in the presence of atrophy of the outer retina.

Adult↗
PubMed1975

Retinal macroaneurysms.

Twenty patients with retinal macroaneurysms were examined and observed for at least 9 months. All these patients were elderly and had evidence of hypertension or systemic vascular disease. Nineteen patients presented with loss of central vision and one patient was asymptomatic. Visual loss was due to macular haemorrhage in 13 patients and macular oedema in 6. Whereas the visual prognosis in patients with haemorrhage was good it was considerably poorer in the patients with macular oedema.

Age Factors↗
PubMed1975

Visual loss due to posterior segment disease in scleritis.

Exudative retinal detachment and oedema of the posterior retina are well-recognized clinical entities for which a cause is rarely found. Scleritis may cause both these clinical syndromes by a spread of inflammation from the sclera into the uveal tract. Although treatment may result in a rapid resolution of scleritis, retinal detachment and macular oedema persist and prove extremely resistant, even to high doses of systemic steroids. Recovery may be incomplete and may occur only after weeks or months of treatment.

Adrenal Cortex Hormones↗