Retinal thinning rates are highest among people with sickle cell retinopathy, compared with those without the sickle cell disease complication, while thinning rates are increased by age and stage of retinopathy, according to a study in JAMA Ophthalmology.

“These findings suggest that identifying anatomic worsening of sickle cell maculopathy through spectral-domain optical coherence tomography (OCT) may be a useful parameter to evaluate the progression of sickle cell retinopathy,” researchers explain.

The longitudinal prospective case-control study looked at 370 adults (711 eyes), and of those, 310 participants (606 eyes) had sickle cell retinopathy, and 60 participants (105 eyes) did not. Researchers sought to determine if examining retinal thinning rates might assist in learning which patients are at risk for sickle cell retinopathy progression. Patients were matched by age and race in both groups. 

Investigators assessed the rates of macular thinning in patients with annual spectral-domain OCT and clinical examinations, identifying ocular and systemic risk factors associated with retinal thinning. Patients with at least 1-year follow-up were studied. Primary outcome was the “comparison of spectral-domain OCT measurements from early-treatment diabetic retinopathy study subfield rates of retinal thinning between eyes with and without sickle cell retinopathy and between different sickle cell hemoglobin subtypes.” A secondary outcome was the identification of ocular and systemic risk factors associated with rates of retinal thinning.


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A total of 344 eyes (56.8%) in the sickle cell group and 46 eyes (43.8%) in the control group had at least 1 year of clinical and spectral-domain OCT follow-up data from baseline. Mean (SD) follow-up was 53.7 months for the sickle cell group and 54.6 months for the control group.

Rates of macular thinning in the sickle cell group were significantly higher than those in the control group in 3 inner quadrants and 1 outer quadrant.

“Patients with sickle cell hemoglobin SC and sickle cell hemoglobin β-thalassemia subtypes had higher rates of retinal thinning than those with the sickle cell hemoglobin SS subtype,” investigators conclude. “Risk factors associated with greater rates of retinal thinning included participant age, stage of retinopathy, previous stroke, and presence of hypertension, acute chest syndrome, or diabetes.” 

They report that hydroxyurea therapy was associated with decreased rates of retinal thinning—and it might be a protective factor.

The study’s limitations included that Goldberg staging for the condition was “based on clinical examination without fluorescein angiography. Fluorescein angiography has been reported to allow greater detection of more advanced stages of sickle cell retinopathy, although clinical examination reliably detected stage 3 retinopathy, and widefield angiographic results did not change clinical management.”

Disclosure: Several study authors declared affiliations with the biotech of pharmaceutical industries. Please see the original reference for a full list of authors’ disclosures.

Reference

Lim J, Niec M, Sun J, Cao D. Longitudinal assessment of retinal thinning in adults with and without sickle cell retinopathy using spectral-domain optical coherence tomography. JAMA Ophthalmol. Published online February 4, 2021. doi:10.1001/jamaophthalmol.2020.6525