Focal irradiation of perforating eye injuries.

Plaques constructed with 125I were used to irradiate the sites of perforating ocular injuries in rabbits. An approximate dose of 16Gy given over a period of 6 days was shown to significantly reduce intraocular cellular proliferation when irradiation was commenced within 24 hours after injury. If irradiation was delayed until day 5, this reduction in cellular proliferation and intraocular membrane formation did not occur. Smaller radiation doses of approximately 6Gy given within 24 hours post-injury and administered over 6 days also reduced the extent of cellular proliferation but was not as effective as the 16Gy dose.

A light microscopic and autoradiographic study of non-irradiated and irradiated ocular wounds.

Focal gamma irradiation was used to limit the intraocular extension of scar tissue which typically occurs after posterior perforating injury to the eye. Standard posterior perforating injuries were created in the right eye of forty-eight rabbits, half of which had the site of perforation focally irradiated using a Cobalt 60 ophthalmic plaque. Non-irradiated wounds healed with profuse formation of highly cellular and vascularised granulation tissue which invaded the vitreous to form contractile vitreo-retinal membranes. In irradiated eyes vitreo-retinal membrane formation was infrequent; the wounds showing only sparse granulation tissue with little or no extension into the vitreous cavity. Autoradiographic studies carried out in a second group of 40 animals showed that the episclera was the main source of the proliferating fibroblasts, and cell counts confirmed that the inflammatory and repair responses in irradiated wounds were both delayed and attenuated.

Failed retinal surgery caused by intraocular gas injection.

Four patients developed inferior retinal redetachment following initially successful surgery which included intraocular injection of air and sulphahexafluoride (SF6) mixture. In each case the intravitreal gas bubble produced vitreoretinal traction which opened inferior retinal breaks and led to retinal separation. Cautious use of intraocular gas is advised when bullous upper rhegmatogenous retinal detachments are accompanied by inferior retinal breaks.

An in-vitro study of irradiated vitreo-retinal membranes.

Standard perforating injuries were created in the right eye of 30 rabbits. Twenty of these had the site of injury irradiated using the radioactive ophthalmic 60Cobalt applicator. Vitreo-retinal membranes obtained from non-irradiated and irradiated eyes were propagated in vitro. The morphology and viability of the cells that grew as a monolayer was studied using phase, light and electron microscopy. The proportions of the different cell types that constituted the monolayer was determined using immunofluorescent staining techniques. Non-irradiated membranes elaborated an abundant outgrowth of healthy cells that were predominantly fibroblasts. Irradiated membranes developed a sparse outgrowth of cells with vacuolated cytoplasm and pyknotic nuclei indicating cell destruction. The majority of the surviving cells were glial, with fibroblasts and retinal pigment epithelial cells forming the remainder.

Experimental posterior perforating ocular injury: a controlled study of the gross effects of localised gamma irradiation.

A pilot study on the effect of localised irradiation applied to the site of a standard perforating injury in the rabbit eye, showed that gamma rays limited the formation of post-traumatic vitreoretinal membranes. A controlled study was therefore undertaken to confirm this observation. Twenty-four pairs of rabbits underwent a standard perforating injury in the right eye. One rabbit of each pair received a radioactive ophthalmic Cobalt applicator and the other a dummy applicator. Nineteen of 24 non-irradiated eyes developed vitreoretinal membranes, with associated traction retinal detachment. Only four of 24 irradiated eyes developed traction retinal detachment.

Localised gamma irradiation and experimental intraocular proliferation.

A controlled study was undertaken to assess the effect of gamma irradiation on post-traumatic intraocular cellular proliferation. A standard perforating injury in the posterior segment of the rabbit eye was used to induce intraocular cellular proliferation and vitreo-retinal membrane formation. The site of injury was irradiated with an ophthalmic Cobalt60 applicator which provided a continuous source of gamma rays. Non-irradiated eyes developed traction retinal detachments associated with post-traumatic vitreo-retinal membranes. Irradiated eyes developed attenuated membranes or atrophic retinal scars, with the retina remaining attached. The membranes in non-irradiated eyes were highly cellular with abundant collagen, while irradiated membranes had fewer cells within a sparse collagen matrix. The episcleral fibroblasts, on autoradiographic studies appeared to be the main source of the cells that formed the proliferating tissue in both non-irradiated and irradiated eyes. In irradiated eyes both the inflammatory response and division of fibroblasts were delayed and reduced.

Ocular immobilization and its role in the management of superior retinal detachment.

Twenty-eight patients with bullous superior half retinal detachments were treated by pre-operative binocular occlusion, retrobulbar Bupivicaine hydrochloride and ocular immobilization using a temporary inferior rectus suture taped to the patient's forehead. Sufficient pre-operative flattening of the retina was achieved in each case to permit successful simple detachment surgery, with release of subretinal fluid in only three eyes. Eye movements were recorded by electro-oculography in five patients during separate periods of binocular occlusion, inferior rectus suture fixation and following a retrobulbar injection of 0.5 per cent Bupivicaine hydrochloride. All three methods of ocular immobilization caused a significant reduction in frequency and amplitude of eye movements compared with periods of unrestricted eye movement.

Analysis of HLA antigen association with proliferative diabetic retinopathy.

One hundred and thirteen patients with insulin dependent diabetes mellitus for at least 15 years were typed for 22 HLA antigens of the A and B series. Fifty-six patients had severe bilateral proliferative retinopathy and 57 had no retinopathy. There was no statistical difference in frequency of HLA antigens between the 2 groups of diabetic patients. There was a significantly higher frequency of HLA B15 and a significant lower frequency of HLA B14, B17 in the combined diabetic groups than in a control population of 200 normal blood donors.

Management of superior-half-bullous retinal detachment.

We treated a selected group of patients with superior-half bullous retinal detachments by preoperative bed rest and immobilisation of the affected eye using a temporary inferior rectus suture taped to the brow. Sufficient flattening of the retina was achieved in each case to permit successful simple extrascleral detachment surgery.

Morbidity and mortality in patients with diabetic retinopathy.

Most studies indicate that diabetics have both a higher mortality rate and a higher morbidity rate secondary to generalized vascular occlusive disease than non-diabetic patients of corresponding age and sex. There is also some evidence that diabetics with proliferative retinopathy are more at risk than diabetics without retinopathy. This study was undertaken to determine and compare the morbidity and mortality rates in diabetics with: (a) No retinopathy, (b) Background retinopathy, (c) Proliferative retinopathy. The records and fundus photographs of 800 diabetics were reviewed and the data statistically analysed according to age, sex, presence and type of retinopathy, morbidity, and mortality. The mortality rates were also compared with the normal population life study data.

Progressive visual failure in acromegaly following external pituitary irradiation.

Four out of twenty-three acromegalic patients selected for treatment with external megavoltage pituitary irradiation between 1961 and 1975 developed progressive visual failure. They had received megavoltage external irradiation through multiple portals from a cobalt-60 unit over a period of 3 weeks. Visual deterioration began 2 months to 6 years after irradiation. In two patients the optic nerves were explored. In both, post-mortem later confirmed radiation damage to the optic nerves and hypothalamus. In one case there was also necrosis of the right frontal lobe with necrosis and inflammation of the bone surrounding the pituitary fossa. In the two other patients, extensive clinical and neuroradiological investigation excluded the presence of a suprasellar mass as a cause for this visual failure and a clinical diagnosis of radiation necrosis was made.

Combined simultaneous cataract glaucoma surgery.

This relatively small series supports the accumulating evidence that a combined cataract extraction and trabeculectomy procedure gives satisfactory results in both respects.