[Evaluation of macular thickness by optical coherence tomography in homozygous SS sickle cell subjects in Yaoundé]

To describe tomographic macular changes in homozygous SS sickle cell patients.

In this cross-sectional study, the macular thickness of 42 patients (77 eyes) with sickle cell SS was compared quadrant by quadrant with that of 82 subjects (148 eyes) without sickle cell disease. The measurements were performed using the Topcon Maestro SD-OCT 3D and then mapped onto the 9 quadrants of the macular grid established by the Early Treatment Diabetic Retinopathy Study. The studied variables were: age, gender, number of annual vaso-occlusive events; prophylactic treatment, visual acuity corrected for distance and near, sickle cell retinopathy; mean macular thickness, mean central (foveolar), and mean temporal inner, nasal inner, superior inner, inferior inner, superior outer, inferior outer, nasal outer, and temporal outer retinal thicknesses. The differences were considered statistically significant for P values < 0.05.

Mean macular thickness was 271.3±20.9μm in homozygous SS sickle cell patients versus 272.4±20.9μm in non-sickle cell patients (P=0.891). This decreases with age; for each year, the macula thins by 0.72μm. The central macular thinning rate was 40.26%. There was significant thinning in sickle cell patients in the nasal outer (P=0.05), temporal outer (P=0.002) and inferior inner (P=0.02) quadrants and non-significant thickening in the inferior outer quadrant. The number of vaso-occlusive events was not significantly associated with thinning of these parameters.

Optical coherence tomography has made it possible to objectify subclinical macular involvement in homozygous SS sickle cell disease.