Screening for Retinopathy

Background
All individuals with SCD and especially those with HbSC are at risk for retinal disease due to vaso-occlusion and its resultant ischemia. Proliferative sickle retinopathy (PSR) is of greatest concern because progression is associated with loss of visual acuity. PSR is the development of sea-fan-shaped neovascular fronds in response to local ischemia from peripheral retinal arteriolar occlusion. The fronds can lead to other complications including vitreous hemorrhage and retinal detachment. Prevalence of proliferative retinopathy reported in a contemporary retrospective study of children with SCD was 4.3 percent. In a study from Jamaica, visual acuity loss attributed to retinopathy was reported in 10 percent of untreated eyes during a 10-year observation period. Prospective clinical studies have demonstrated the benefit of laser photocoagulation in reducing rates of visual acuity loss and decreasing incidence of vitreous hemorrhage. Surgical intervention may be indicated for certain complications such as vitreous hemorrhage. The onset of sickle retinopathy is in childhood; however, screening requires a dilated eye examination and the ability to do so will vary according to the child’s ability to tolerate the exam.

Summary of the Evidence
No RCTs of retinal screening in people with SCD were found. Twelve observational studies addressed eye examinations for individuals with SCD, primarily children and adolescents. Of these, five were longitudinal and involved 1,261 individuals, and seven were cross-sectional. Genotypes involved were HbSS, HbSC, and HbSb-thalassemia. No studies have been published comparing screening for retinopathy with no screening, nor were data found to evaluate diagnostic accuracy or screening intervals. The overall quality of the screening data were considered low.

In these studies, “eye examinations” varied, and not all included dilation of the pupils. The most comprehensive report describes a 20-year prospective study of an inception cohort of 473 individuals from Jamaica. Annual eye exams including dilation were performed from age 5, and fluorescein angiography was performed from age 6 unless patients had an allergy to fluorescein. Fifty-nine of those studied developed proliferative retinopathy. The incidence of retinopathy increased with age, and by the ages of 24 to 26, PSR was present in 43 percent of those with HbSC and 14 percent of people with HbSS. In a retrospective study of 263 children with SCD, including people with HbSS, HBSC, and HbS§-thalassemia, the age of onset of retinopathy (proliferative and non proliferative) was, on average, 12.8 years.

Recommendations

1. In people with SCD, refer to an ophthalmologist for a dilated eye examination to evaluate for retinopathy beginning at age 10.
(Strong Recommendation, Low-Qualify Evidence}
2. For people having a normal dilated retinal examination, re-screen at 1—2 year intervals. (Consensus—Pane/Expertise}
3. Refer people with suspected retinopathy to a retinal specialist. (Consensus—Pane/Expertise}

Review the Anatomy

Here is a graphic edited by Dr. Rob for your review of the concepts.