New classification of peripheral retinal vascular changes in sickle cell disease

The systemic complications of homozygous sickle cell disease (SS) are more severe than in sickle cell haemoglobin C (SC) disease, and yet visual loss due to proliferative retinopathy is more common in the latter. This anomaly is unexplained. It is believed that proliferative disease occurs in response to closure of the peripheral retinal vasculature, yet a systematic longitudinal survey of the peripheral retinal vascular bed has not been undertaken. In the Jamaica Sickle Cohort study all subjects are scheduled to receive annual ocular examination and fluorescein angiography. The results have now been analysed in subjects with SS and SC disease using a new classificaton system based on a comparison of the peripheral retinal vascular bed with that recorded in the cohort with normal haemoglobin (AA) genotype. The vascular patterns could be classified as qualitatively normal (type I) or abnormal (type II). An abnormal vascular pattern was identified more commonly with age, in a significantly larger proportion of subjects with SC than SS disease, and was associated with the development of proliferative disease. In order to establish the dynamics of change, the angiograms were analysed in the 18 subjects (24 eyes) who developed proliferative disease. It is shown that qualitatively normal vascular pattern may be retained despited loss of capillary bed and posterior displacement of the vascular border. A border which is qualitatively abnormal does not revert to normal, and once abnormal, continuous evolution may occur before development of proliferative lesions. The peripheral border of the retinal vasculature was too peripheral to photographed in 13 of the 24 eyes before it becoming qualitatively abnormal. It is concluded that a normal border, if posterior, results from gradual modification of the capillary bed and indicated low risk of proliferative disease. A qualitatively abnormal vascular border occurs as a radical alteration of retinal perfusion in subjects in whom little modification of the vascular bed occurred before the event, and signal risk of proliferative disease. This classification system is useful in identifying the likelihood of threat to vision in young Jamaicans with sickle cell disease, and the higher frequency of proliferative retinopathy in SC can be explained by the higher prevalence of a qualitatively abnormal peripheral retinal vasculture (AU)

Peripheral retinal vasculature in normal Jamaican children

A prospective study of the peripheral retinal vasculature in a Jamaican cohort of subjects with sickle cell disease has been in progress over a period of 12 years using flourescein angiograpphy. Various vascular patterns were identified but their significance was unclear since no comparable records were available in subjects of a similar age with normal (AA) haemoglobin genotype. Fluorescein retinal angioscopy and angiography have been performed in 76 heamoglobin AA controls participating in the cohort study. The peripheral retinal capillary bed could be seen and photographed in a limited portion of the temporal peripheral fundus in a majority of this group, and there was considerable variation in the vascular pattern which could be characterised. These observations allow deviations from normal to be identified in the retinal vasculature in subjects with sickle cell disease (AU)

Screening for opthalmic manifestations of sickle cell disease in the United Kingdom

There are marked variations in the manifestations of sickle cell disease in different populations. The occular complications of this condition amongst the Afro-Caribbeans living in the United Kingdom have not previously been reported. We present the preliminary results of an opthalmic screening programme at King's College Hospital, London. One hundred eyes of 50 patients with sickle cell disease were assessed. Full ocular examination was performed including fundus fluorescein angiography. We have looked at the haemotological and clinical profile of the patients involved as well as the number of days spent in the hospital during the year preceding the examination. The incidence of Grade 11 retinopathy was found to be significantly higher than grade 1 in SC disease. This concurs with the results of the Jamaican screening and confirms that the patients are at higher risk of visual impairment than those wuth the SS disease. Our results also agrees with the Jamaican experience which suggests that visual morbidity is mostly due to complications of proliferative sickle cell retinopathy (PSR). However, the findings in patients without proliferative changes are different; in particular, angloid streaks leading to disciforms are an important cause of visual loss in Jamaica, but were not seen in any of the 98 eyes examined in this study. No correlation was found between the grade of retinopathy and age, sex, systemic complications and various haematological parameters except for the percentage of haemoglobin F, which was significantly higher in patients with grade I (7.6) compared with grade II (4.2) retinopathy (p=0.0127)(AU)

Recurrent visual loss in homozygous sickle cell disease

In sickle cell retinopathy vascular involvement is most frequently recognised at the retinal periphery but obstruction of perimacular arterioles and of major retinal vessels may also occur. This report describes a patient with homozygous sickle cell (SS) disease with recurrent occlusion of major retinal vessels associated with recurring transient impairment of visual function. (Summary)

Retinal changes in sickle cell/hereditary persistence of fetal haemoglobin syndrome

We describe for the first time retinal changes in sickle cell/hereditary persistence of fetal haemoglobin syndrome, which is a rare and benign disorder. The changes are qualitively similar to retinal disease seen with sickle haemoglobin and sickle C haemoglobin, but are mild (AU)

Sickle cell retinopathy in young children in Jamaica

Ophthalmological examinations were performed on 59 of the 74 (80 percent) children with homozygous sickle cell (SS) disease and on 37 of the 54 (69 percent) children with sickle cell-haemoglobin C(SC) disease, aged 5-7.5 years, within the cohort study of sickle cell disease. Arteriolar sheathing was the commonest retinal vessel abnormality, occurring in 30/59 (51 percent) SS children and in 11/37 (30 percent) SC children. Peripheral arteriolar closure was observed in 14 (24 percent) SS children and in 6 (16 percent) SC children. Arteriovenous anastomoses were seen in 3 children, but proliferative retinopathy was not identified. Capillary changes often occurred in patients without confluent closure, suggesting that complex remodelling of the capillary bed may precede retinal nonperfusion. Discrete retinal patches similar to schisis cavities resulting from intraretinal haemorrhages were found in 22 (37 percent) SS children and in 9 (24 percent) SC children, but haemorrhages were observed in only 2 patients (1 SS, 1SC). Vitreous opacities were common and were generally associated with retinal vessel disease. Retinal changes were consistently more common in children with SS disease, though the differences failed to reach statistical significance. The prevalence of peripheral vascular closure and retinal patches showed a significant upward trend with age. These observations contrast with the greater prevalence of proliferative retinopathy characterising SC disease in adults.(AU)

Retinal and choroidal neovascularization in sickle cell disease.

Small vessel obstruction characterizes sickle cell disease and when occurring in the peripheral retinal vessels, initiates a sequence of vascular events which may culminate in the development of proliferative sickle retinopathy (PSR). Repeated examinations of the retinal vasculature of patients with different genotypes of sickle cell disease over the last 10 years (Condon and Serjeant,1972a,b,c; 1975; 1980a) have allowed observations on the natural history of PSR and on factors related to its development. Choroidal neovascularization has been a common complication of a trial of xenon arc photo-coagulation in PSR. Observations on the aetiology and natural history of both retinal and choroidal neovascularization are presented in this report. (AU)

Photocoagulation and diathermy in the treatment of proliferative sickle retinopathy

The O'Malley Log II portable photocoagulator was used to treat the worse eye of 36 patients with proliferative sickle cell retinopathy flat on the retinal surface. The technique involved direct coagulation of the feeder arterioles before treatment of the new vessels themselves. The photocoagulator was most successful in treating the lesions and 131 of 137 retinitis proliferans (RP) lesions were occluded. In only one RP lesion did the photocoagulator have insufficient power to occlude the lesion. Vitreous haemorrhage occurred in only one patient and small round localized retinal haemorrhages in five. The Manchester portable diathermy machine successfully occluded all 29 raised RP lesions and fifty feeder arterioles in thirteen patients. Anterior segment ischaemia occurred in only one patient who had advanced traction retinopathy involving 360 degrees of arc of the retinal circumference before treatment. No recurrence of retinopathy over a 2-year follow-up period was seen in seven patients and in the remainder there was no recurrence in the 2 months after treatment. (Summary)

Ocular findings in children with sickle cell haemoglobin C disease in Jamaica

The ophthalmological findings in 54 Jamaican children with SC disease are reported. Evidence of peripheral retinal vessel disease was present in 94 percent and retinitis proliferans in 11 percent. Retinitis proliferans was noted as early as 7 years of age and was more common in patients with high haemoglobin levels. There was an unequivocal progression in severity of retinopathy in eight out of eleven children examined 2 years previously. The pathological processes leading to sickle cell proliferative retinopathy are well established in childhood and attempts at prophylactic therapy should be instituted at an early age. (Summary)

Ocular findings in homozygous sickle cell anemia in Jamaica

Retinal detachment, brown mottled areas and microcapillary abnormalities at the posterior pole are previous undescribed retinal features of sickle cell anemia that were found in a series of 76 Jamaicans with homozygous sickle cell anemia. These subjects were consecutive patients in a sickle cell clinic during a one-month period; thus, the series is unique in that bias in selective inclusion of cases with ocular pathology was avoided. Tortuosity of the major retinal vessels, previously reported as a major feature of the retinopathy was found in unaffected relatives of SS patients in the same family with normal hemoglobin genotype. Angioid streaks were not seen in this series. (AU)