Biomedical subjects
Publications and source records attributed to Z J Gregor.
Anterior migration of an extrascleral explant is an uncommon complication following buckling procedures. We report five patients where the explant cheesewired through the rectus muscle insertion following retinal detachment surgery. Muscles were not disinserted at the time of surgery in any case. Ocular motility problems were only seen in two patients. The probable mechanisms of this hitherto unreported complication are discussed.
An 18-year-old woman with retinal vasculitis developed multiple retinal arterial aneurysms over a period of 3 years. Subsequently she developed macular oedema, peripheral neovascularisation, and vitreous haemorrhage and was treated with systemic steroids, laser photocoagulation, and vitreoretinal surgery. No systemic cause for vasculitis was found. Serial fluorescein angiography demonstrated gradual resolution of the arterial aneurysms over the subsequent 7 years.
This study compared the effects of vitreous gel, retrohyaloid fluid and subretinal fluid from diabetic and non-diabetic eyes on the proliferation and migration of retinal microvascular cells in vitro. Intraocular fluids were obtained from eyes undergoing repair of retinal detachment, due either to proliferative diabetic retinopathy or rhegmatogenous retinal detachment associated with a degree of proliferative vitreoretinopathy. The results demonstrated that the intraocular stimulatory activity for the proliferation of retinal microvascular endothelial cells varied between the different ocular compartments. The mitogenic and migrational activity in vitreous gel was greater than that of either the subretinal or retrohyaloid fluids of the same eye, and the activity of subretinal fluid was intermediate between that of the vitreous gel and the retrohyaloid fluid. There was no significant difference between the activities of the samples from diabetic and non-diabetic eyes.
The size of the final macular scar in subretinal neovascularisation (SRNV) is one of the most important determinants of final visual function in patients with subfoveal disease. We studied patients with bilateral macular scars from age-related subretinal neovascular membranes retrospectively in order to determine whether or not fellow eyes behave similarly. We found a significant correlation between eyes in terms of final scar size (r = 0.50, p less than 0.01). We found that 50% of fellow eyes with large macular scars (greater than 3 x 10(6) microns2) had similar sized lesions, while only 16% of fellow eyes with small macular scars (less than 0.5 x 10(6) microns2) had large scars (p less than 0.01). We discuss the significance of these findings in relation to the pathogenesis of subretinal neovascular membranes, and their implications for treatment.
We report the results of a randomised treatment trial of macular grid photocoagulation in 91 eyes with diffuse diabetic macular oedema followed up for at least two years comparing Krypton red with Argon blue/green lasers. At two years, macular oedema had improved equally in both groups, and the visual acuity was unchanged or better in 85% of eyes treated with Argon and in 79.5% of eyes treated with Krypton laser. No statistically significant differences were observed between the two groups in terms of visual acuity or the degree of oedema. We conclude that the observed effect of grid laser treatment in diffuse diabetic macular oedema did not depend on the wavelength of the laser light used in this study.
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Delayed suprachoroidal haemorrhage occurred in 13 eyes in a consecutive series of 432 cases undergoing trabeculectomy or anterior chamber (A/C) tube drainage operations. Aphakia and vitrectomy were associated with an increased risk of haemorrhage, whilst advanced age, myopia, systemic hypertension and high preoperative intraocular pressure were not. Haemorrhage occurred more often after A/C tube drainage operations than after trabeculectomy. An explanation for this may be that eyes requiring A/C tube drainage operations have had multiple previous operations including lens extraction and vitrectomy, have a higher pre-operative intraocular pressure and a greater fall in pressure after operation when compared to eyes undergoing trabeculectomy. Post-operative hypotony should be avoided in high-risk eyes.
We have treated 26 retinal angiomas of less than 4.5 mm in size in 15 eyes using repeated applications of contiguous argon blue green laser burns. All except one of the angiomas regressed without a massive exudative response of treatment. Haemorrhage occurred in two cases but only affected the visual outcome in one eye. Traction retinal detachment persisted in 50% of the large angiomas, despite regression of the tumour.
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The appearance of large silicone oil globules in the anterior chamber of phakic eyes leads to serious intraoperative and postoperative problems. Using hyaluronate sodium, the silicone can be safely removed from the anterior chamber, the crystalline lens may be saved, and the posterior segment procedure can be completed.
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.
The results of a retrospective study of the effects of silicone oil removal from 85 eyes in 85 patients are reported. Pars plana vitrectomy and fluid/silicone oil exchange had been undertaken for retinal detachments associated with giant retinal tears or with proliferative vitreoretinopathy in all cases. Clinically significant cataract developed in 60% of lenses that were clear at the time of oil removal, and 85% of pre-existing lens opacities progressed. Removal of oil from 19 eyes with uncontrollable glaucoma was combined with drainage surgery in 14 eyes. Postoperatively the intraocular pressure was controlled in 13. Corneal decompensation either improved or was unchanged in eight out of nine patients after silicone oil removal, and three patients had penetrating keratoplasty and maintained a clear corneal graft. Patients who did not have glaucoma or keratopathy at the time of silicone oil removal did not develop these complications.
A retrospective study of the effects of silicone oil removal was carried out on 85 patients who had undergone pars plana vitrectomy and silicone oil exchange for giant retinal tears or proliferative vitreoretinopathy. Silicone oil was removed either as part of the treatment of anterior segment complications such as glaucoma and keratopathy (25 patients) or in order to prevent these complications (60 patients). The major complications of the removal of silicone oil were retinal redetachment (25%), hypotony (16%), and expulsive haemorrhage (1%). The length of time that the oil remained in the eye and the presence of anterior segment complications did not appear to have an effect on the rate of retinal redetachment or hypotony.
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.
The changes in corneal curvature in the first six months after cataract extraction were studied by performing sequential keratometry on a group of 57 patients. 8/0 Virgin silk interrupted sutures were used for the closure of corneoscleral incisions, and 10/0 monofilament tied in double running (bootlace) or single running (continuous) fashion was used for corneal wound closure. A high degree of with-the-rule astigmatism was evident in all patients two weeks postoperatively, but thereafter the character of the astigmatism produced by 8/0 virgin silk and 10/0 monofilament closure was quite different: in the 8/0 virgin silk group there was an early and pronounced shift in the axis of astigmatism to against-the-rule, whereas in the 10/0 monofilament group there was little further change in the astigmatism unless the sutures were removed. Wound compression and wound gape as factors responsible for these changes are discussed.
A case of inadvertent intraocular injection of Depomedrone (methylprednisolone acetate) and its management by vitrectomy is discussed, with a review of previously reported cases.
Results and complications of surgical treatment for retinal detachment in thirteen patients with proliferative sickle cell retinopathy are reported. Eleven had maintained or improved visual acuity after treatment. Methods and complications of exchange transfusion in eight patients are described. The pathogenesis and methods of treatment of these retinal detachments and the benefits of exchange transfusion are discussed.
The clinical findings of 20 patients with an isolated peripheral retinal mass secondary to retinal telangiectasis were reviewed. The important clinical features were subretinal exudation, vitreous haemorrhage and retinal detachment. No associated systemic abnormalities were identified. Early results suggest that cryotherapy is effective for the reduction of subretinal exudation but not for macular oedema. Patients with extensive retinal detachment complicated by vitreous haemorrhage and epiretinal membrane formation were treated with vitreoretinal surgery.