Retinal Thinning Rates Increase as Sickle Cell Retinopathy Progresses

Jennifer I. Lin, MD

Retinal thinning rates might be a useful tool in identifying patients at a higher risk of sickle cell retinopathy progression.

A team, led by Jennifer I. Lim, MD, Department of Ophthalmology, University of Illinois at Chicago, assessed the rates of macular thinning in adults with and without sickle cell retinopathy and identified ocular and systemic risk factors associated with retinal thinning.

The investigators used spectral-domain optical coherence tomography (OCT) to identify macular thinning in the study patients.

In the longitudinal prospective case-control study, the investigators enrolled adult patients from a university-based retina subspeciality clinic between February 2009 and July 2019.

Matching Patients

Each patient with sickle cell retinopathy was matched by age and race with patients without sickle cell retinopathy.

The patients also received an annual spectral domain OCT and clinical examinations.

The final analysis included patients who received at least 1 year of follow-up.

The investigators sought primary outcomes of 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.

They also sought secondary outcomes of the identification of ocular and systemic risk factors associated with rates of retinal thinning.

Patient Population

The study included 370 adults (711 eyes examined), 310 of which (606 eyes) had sickle cell retinopathy and 60 individuals (105 eyes) who did not. A total of 175 of the 310 sickle cell retinopathy patients and 31 participants in the control group had at least 1 year of clinical and spectral-domain OCT follow-up data from baseline.

The mean follow-up was 53.7 months for the target group and 54.6 months for the control group.

The rates of macular thinning in the sickle cell group were substantially higher than the control group for the inner nasal (difference, −1.18 μm per year; 95% CI, −1.71 to −0.65 μm per year), inner superior (difference, −1.03 μm per year; 95% CI, −1.78 to −0.29 μm per year), inner temporal (difference, −0.61 μm per year; 95% CI, −1.16 to −0.07 μm per year), and outer nasal (difference, −0.41 μm per year; 95% CI, −0.80 to −0.03 μm per year) quadrants.

What Was Learned

In addition, 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.

Risk factors linked to greater rates of retinal thinning include age, stage of retinopathy, previous stroke status, and presence of hypertension, acute chest syndrome, or diabetes.In addition, hydroxyurea therapy was associated with decreased rates of retinal thinning, which could be a protective factor.

“In this study, rates of retinal thinning were higher among participants with sickle cell retinopathy compared with those without sickle cell retinopathy, and thinning rates increased with participant age and stage of retinopathy,” the authors wrote. “These findings suggest that identifying anatomic worsening of sickle cell maculopathy through spectral-domain OCT may be a useful parameter to evaluate the progression of sickle cell retinopathy.”

The study, “Longitudinal Assessment of Retinal Thinning in Adults With and Without Sickle Cell Retinopathy Using Spectral-Domain Optical Coherence Tomography,” was published online in JAMA Ophthalmology.