Krishan C. Nagpal

Ocular manifestations of sickle hemoglobinopathies.

The ocular manifestations of sickle cell hemoglobinopathies, while often not severe enough to affect vision, may develop in proliferative stages, resulting in arteriolar-venular anastomoses, neovascular proliferations, vitreous hemorrhage and retinal detachment. The authors review the historical, biochemical, and geographic aspects of the disease, and provide detailed descriptions of findings in theconjunctiva, uvea and fundus, with particular emphasis on the retina. Pathogenesis, histopathologic and clinical appearance, and modes of treatment are discussed.

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.

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.

Angioid streaks and sickle haemoglobinopathies.

Five patients had angioid streaks associated with sickle cell haemoglobinopathy. Other diseases associated with angioid streaks were ruled out, as was elastic tissue degenegation in sickle cell patients. After studying over 350 patients, we believe the incidence of angioid streaks in sickle cell disease to be between 1 and 2 per cent.

Evolution of the retinal black sunburst in sickling haemoglobinopathies.

In a prospective study of 38 patients, who were initially selected as being at an early stage of sickling retinopathy, three developed circular black chorio-retinal scars (black sunbursts) during a period of 6 to 24 months. These lesions appear to be the sequelae of intraretinal and subretinal haemorrhage. They occur in the fundus periphery and do not interfere with vision.

Management of persistent hyperplastic primary vitreous by pars plana vitrectomy.

Two children with persistent hyperplastic primary vitreous (PHPV) underwent vitrectomy and lensectomy via the pars plana to remove the fibrovascular stalk. Postoperatively the eyes were quiet, only a slight vitreous haze obscured the fundus view in the immediate postoperative period, and the stumps of the stalks retracted. Early surgical treatment of PHPV may prevent later serious complications.

Dark-without-pressure fundus lesions.

Seven black patients had dark brown homogeneous geographical areas of the fundus. Six cases were associated with sickle cell haemoglobinopathies and one was associated with systemic hypertension. These flat lesions were uniform in colour and occurred in the posterior pole or in the midperiphery. They appeared to be transient and often disappeared leaving no residue. The cause is unknown. By analogy with white-without-pressure fundus lesions, we have called these areas dark-without-pressure.

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.

Fifty consecutive eyes with anterior segment disease treated by the pars plana approach.

Results of a pars plana approach using the Peyman vitrophage to treat various anterior segment diseases are presented in 48 patients (50 eyes). These included cases of ocular trauma, congenital cataracts, complications following unplanned and planned extracapsular cataract extractions and phacoemulsification, and dense secondary membranes. Visual acuity improved in 86%, remained unchanged in 10% and worsened in 4% of all eyes.