Abstract
Purpose:
Macular thinning has been described in patients with sickle cell disease. We aimed to compare central retinal thickness measurements between patients with HbSS and HbSC genotypes.
Methods:
Spectral domain OCT scans were retrospectively reviewed. Scans were excluded if other macular pathology was present (such as diabetic maculopathy or epiretinal membrane) or if the central 3 mm diameter foveal area was not included or was contaminated by motion artefact. One eye was included per patient: if both eyes were eligible for inclusion, the right eye was chosen; if multiple scans at different times were present, the most recent time point with eligible scans (for both eyes) was selected. If the scan centre did not correspond to the foveal centre, the measurement grid was re-centred manually. The observer was blinded to patient genotype when analysing the images. Comparison was made between macular thickness measurements in the central 1 mm subfield and in the superior, nasal, inferior and temporal subfields (extending out to 3 mm), corresponding to the central Early Treatment of Diabetic Retinopathy Study macular map sectors.
Results:
41 eyes from 41 patients were included (24 HbSC, 17 HbSS). Mean ages (SD) were 44.2 (13.7) and 43.2 (11.3) for HbSC and HbSS groups respectively, and did not differ significantly between the two groups. 71% of patients in each group were female. Mean central (1 mm) thickness measurements (SD) were 212 (30) microns for the HbSC group and 205 (22) microns for HbSS patients. Mean (SD) superior, nasal, inferior, temporal subfield thicknesses were, respectively, 297 (28), 294 (27), 287 (31), 273 (27) microns for HbSC patients, and were 268 (32), 277 (39) 269 (45) and 240 (41) microns for HbSS patients. Differences between groups were very significant for the superior subfield (p = 0.0038, unpaired t test) and for the temporal subfield (p = 0.0041).
Conclusions:
In our study, all mean macular thickness measurements were lower in HbSS patients compared to HBSC patients, and comparisons were significant for superior and temporal subfields. Whilst several studies have shown that HbSC patients are more likely to develop proliferative disease, HbSS patients appear to demonstrate more marked macular thinning.
Keywords: 585 macula/fovea •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)