Proliferative retinopathy in sickle cell trait. Report of seven cases.

Seven patients had sickle cell trait (hemoglobin AS) and vasoproliferative retinopathy. The retinal abnormalities in these seven patients were indistinguishable from those seen in patients with clinically significant sickling hemoglobinopathies (sickle cell-hemoglobin C disease, hemoglobin S-thalassemia disease, and sickle cell anemia). All seven patients also had some evidence of associated systemic disease such as diabetes, syphilis, tuberculosis, or sarcoidosis. In the presence of an associated systemic disease, marked retinopathy can occur in the ordinarily benign condition of sickle cell trait.

The angiographic pattern of the peripheral retinal vasculature.

Various diseases of the peripheral retinal vasculature, such as sickle cell retinopathy and Eales' disease, demonstrate vascular abnormalities. For comparative purposes, we documented angiographically the peripheral retinal vasculature in young, healthy subjects. Our findings showed the density of the capillary bed to be highest in the posterior pole and least concentrated toward the periphery. Peripheral capillaries are considerably larger than those found posteriorly and have fewer bifurcations. Our technique also detected the periarterial capillary-free zone and the zone without capillaries adjacent to the ora serrata. These aspects were consistent with findings of other investigators using in vitro techniques. By creating a standard of normalcy in vivo, the angiographic technique allows vascular abnormalities evident in diseases of the peripheral retinal vasculature to be more precisely defined and compared.

Papillopathy caused by amiodarone.

Disc swelling and hemorrhages appeared in three eyes of two men receiving amiodarone hydrochloride for cardiac arrhythmias. The initial diagnosis was ischemic optic neuropathy, but visual acuity was preserved, and visual field changes were present in only one eye. Amiodarone is a cationic amphiphilic compound, and other drugs with this property have keratopathy, retinopathy, and optic neuropathy as side effects. We believe our patients had an amiodarone-induced papillopathy.

Optic disc neovascularization of uveal (choroidal or posterior ciliary) origin.

Fluorescein angiography during the choroidal phase of perfusion has been used to study the origin of blood vessels comprising neovascular tissue of the disc. These newly formed vessels were shown to derive their blood supply primarily from the uveal circulation rather than from the retinal circulation. This is related to the observation that many normal disc blood vessels originate from the choroidal or posterior ciliary circulation.

Retinal macroaneurysms.

Five patients had macroaneurysms of the retinal arterioles. These macroaneurysms may be observed without pathologic sequelae or may be associated with circinate retinopathy, intraretinal hemorrhage, subretinal hemorrhage, or intravitreal hemorrhage. They may also evolve into more widespread vascular anomalies resembling adult Coats disease in some respects. Photocoagulation therapy is occasionally indicated.

Peripheral retinal neovascularization in sarcoidosis.

Three black patients with peripheral retinal sea fan neovascularization were found to have sarcoidosis. The periphlebitic process may be the cause of stasis, hypoxia, and a secondary vasoproliferative stimulus. We noted the peculiar finding of a vessel passing through the neovascular tissue into the peripheral retina. This feature may help in the differential diagnosis.

Evolution of neovascularization in sickle cell retinopathy. A prospective fluorescein angiographic study.

With prospective observations we have documented by fluorescein angiography the development of retinal neovascularization in the eyes of patients with sickle cell-hemoglobin C disease (hemoglobin SC). In each patient, arteriolarvenular (AV) anastomoses occurred before the development of neovascular sea fans. To our knowledge, this report constitutes the first such documentation in the literature. New sea fans from AV anastomoses appeared throughout an average interval of 18 months (range, 8 to 36 months) in approximately 21% of young adults with hemoglobin SC. Each year approximately 14% of young patients with hemoglobin SC may develop retinal neovascularization.

The conjunctival sickling sign, hemoglobin S, and irreversibly sickled erythrocytes.

Sixty-five patients with hemoglobins AS, SC, and SS were investigated in a masked fashion. We observed a statistically significant positive correlation between the severity of conjunctival sickling signs and the counts of irreversibly sickled cells in each hemoglobinopathy group. We also observed a statistically significant positive correlation between the severity of the conjunctival vasculopathy and the percentage of sickle hemoglobin in the total group of patients with hemoglobins AS, SC, and SS.

Choroido-vitreal neovascularization after argon laser photocoagulation.

Argon laser photocoagulation performed to destroy retinal neovascularization in two patients with proliferative sickle retinopathy and one patient with sarcoidosis was complicated by the development of choroidal neovascular tissue that extended through the photocoagulated retina into the vitreous. Attempts to obliterate the neovascular growth were successful in two cases. In the case that did not respond to repeated therapeutic procedures, the possibility of a direct communication with the long posterior ciliary artery was suggested by the presence of a chorioretinal defect in the vicinity of the photocoagulated area.

Acute choroidal ischemia as a complication of photocoagulation.

Acute choroidal vascular insufficiency as a complication of photocoagulation has been little noticed. In 17 eyes of 16 patients photocoagulated with either xenon or argon sources for proliferative sickle cell retinopathy, gray lesions of the fundus developed peripheral to the photocoagulation sites. Histologic examination of similar gray lesions produced in monkeys showed necrosis and atrophy of the outer half of the retina. Intense photocoagulation of the human fundus, even with smaller spot sizes, may occlude a choroidal artery, producing separate gray lesions of distinctive shape. The lesions in both the patients and the monkeys progressed to granular hyperpigmentation by two to three weeks after photocoagulation.

Spontaneous regression (autoinfarction) of proliferative sickle retinopathy.

Of 45 patients with proliferative sickle retinopathy in stages III, IV, and V, nine patients (eight with hemoglobin SC disease, one with sickle cell thalassemia) showed spontaneous regression (autoinfarction) of retinal sea fans. One mechanism involved in autoinfarction of neovascular tissue is progressive, centripetal retraction of the anterior vascular arcade of the peripheral retina. In addition, vitreous traction on feeder vessels may result in sluggish blood flow and occlusion of these vessels, or may tear the sea fan completely away from its feeder vessels. In view of the many incidences of vitreous hemorrhages that occur in patients with proliferative retinopathy, however, we recommend treatment of neovascularization rather than prolonged observation.

Spontaneous remodeling of the peripheral retinal vasculature in sickling disorders.

Periodic photographic and angiographic surveys of patients with the earliest stages of sickle retinopathy showed a number of fundus findings. In seven cases (sickle cell anemia, four; sickle cell hemoglobin C, three), these findings included: (1) a variety of vascular abnormalities in the equatorial and post-equatorial retina such as segmented dilations of the vessel walls, hairpin-shaped vascular loops, hypertrophic, tortuous A-V anastomoses, intraluminal plugs, closure and loss of capillary bed, and terminal budding of capillaries; and (2) a continuous, spontaneous remodeling of the peripheral retinal vasculature due to successive closures and reopenings of equatorial retinal vessels. A centripetal recession of the peripheral retinal vasculature usually resulted. No correlation between the ophthalmoscopic and the systemic condition of the patients could be made.

Macular and perimacular vascular remodelling sickling haemoglobinopathies.

The posterior pole vasculature of 100 patients with different sickling haemoglobinopathies was studied prospectively over a period of three years. Various abnormalities of the posterior pole vasculature were seen in 29 per cent of the patients. Continuous remodelling of the macular and perimacular vasculature occurred. Visual acuity was variably affected and sometimes remained intact.

Macular abnormalities in papilledema from pseudotumor cerebri.

Three young women with papilledema secondary to pseudotumor cerebri evolved mottled macular pigmentation with preservation of normal visual acuity. Choroidal folds or macular star figures were observed. These macular changes could represent the sequelae of either macular edema or a mechanical disruption of the retinal pigment epithelium. The mechanism of choroidal folds in papilledema remains uncertain.

Macular infarction in sickle cell B+ thalassemia.

A young black girl with sickle cell B+ thalassemia sustained macular infarction of the right eye due to multiple arteriolar occlusions. Follow-up examination revealed optic atrophy as well as microvascular abnormalities of the right macula. To the authors' knowledge, this is the first reported case of macular infarction in sickle cell B+ thalassemia.

Iris retraction syndrome after intraocular surgery.

BACKGROUND: The authors report the postoperative development of iris retraction syndrome in two individuals. This is a rare syndrome that can present with pupillary block after an unrepaired rhegmatogenous retinal detachment. PATIENTS: The authors report two patients who had the iris retraction syndrome shortly after intraocular surgery. One patient had pupillary block that developed 6 months after cataract extraction and posterior chamber intraocular lens implantation. A second patient had uveitis, hypotony, and pupillary seclusion 4 weeks after pars plana vitrectomy. RESULTS: Both patients were treated successfully with a scleral buckling procedure and peripheral iridectomy. CONCLUSION: Postoperative uveitis that occurs with iris retraction and pupillary seclusion should alert the physician of an occult retinal detachment and warrant a thorough dilated funduscopic examination. Features unique to this report include the development of iris retraction syndrome in the presence of a pseudophakos, the rapidity of onset of this disorder after retinal detachment, and its masquerade as a persistent postoperative uveitis.

Amiodarone for tachyarrhythmias: pharmacology, kinetics, and efficacy.

Amiodarone, although widely studied in Europe, is a recent addition to the investigational antiarrhythmics being used in the U.S. Pharmacologically, its primary cardiac effects are to increase coronary artery blood flow, increase the effective refractory period, and produce an atropine-resistant bradycardia. Amiodarone is incompletely (approximately 50 percent) and slowly (peak serum concentration approximately 6 h) absorbed. With chronic administration, it deposits both in adipose tissue and in organs with high blood perfusion. It has an apparent elimination half-life of 15-45 days, which presents unique dosing problems. The apparent therapeutic range is 0.6-3 microgram/ml. Amiodarone is 85-95 percent effective in the treatment of atrial tachyarrhythmias and 70-80 percent effective in ventricular tachyarrhythmias. It appears to be of particular value in chronic atrial fibrillation/flutter because it may be able to maintain sinus rhythm after cardioversion. Side effects, although uncommon, may prevent the drug from becoming a standard of therapy. Drug interactions, particularly with warfarin and digoxin, as well as pulmonary fibrosis are of concern.

Vitrectomy in sickling retinopathy: report of five cases.

The unique problems encountered in sickle patients include the need to remove peripheral vitreous if perfusing sea fans-which can bleed after vitrectomy-are present at the time of surgery. However, peripheral vitrectomy is riskier than central vitrectomy alone. If visualization of the sea fans is sufficient, it is safer to close the sea fans prior to vitrectomy in order to obviate the need for peripheral vitrectomy; then, only central vitrectomy is performed. When sea fans cannot be closed prior to vitrectomy, peripheral vitreous is removed to allow early photocoagulation of the sea fans before they bleed again. Four case presentations illustrate these principles. Vitrectomy relieved severe vitreous traction that complicated retinal detachment in the fifth patient, thereby eliminating the need for a tight encircling structure, which can be poorly tolerated in patients with SC hemoglobin.