Abstract
Purpose: :
Studies have shown that patients with sickle cell hemoglobinopathies (SCH) have focal macular thinning in over 50% of eyes. However, knowledge about peripapillary RNFL changes in SCH is limited. The aim of this study is to determine whether sickle cell patients have RNFL thickness abnormalities, which could impact glaucoma evaluations.
Methods: :
In this prospective study, SCH (SS, SC, and S-Thalassemia) patients and age similar, race-matched controls underwent SDOCT of the macula and optic nerve head (ONH) using the Heidelberg Spectralis. Patients with prior retinal treatments (laser or surgery), diabetes mellitus, or other ocular diseases were excluded. RNFL thickness measurements within each of the 7 subfields of the ONH as displayed on the SDOCT report were recorded. The sickle patients were further grouped into those with focal macular thinning (Group 1) and those without (Group 2). ANOVA testing and post hoc analysis with the Tukey test were performed to assess for RNFL thickness differences among Group 1, Group 2 and controls.
Results: :
SDOCT images from 73 eyes of 42 sickle cell patients and 24 eyes of 13 control patients were analyzed. Of the 73 eyes from sickle cell patients, 31 represented Group 1 and 42 represented Group 2. Mean ages among each group were not statistically different (p = 0.28). Mean RNFL thicknesses were significantly different among the 3 groups in 4 of 7 (57%) ONH subfields. Group 1 had significantly thinner RNFL in the nasal, (66 vs. 85 µm, p=.0001), inferotemporal (140 vs. 157 µm, p=.0206), superonasal (105 vs. 123 µm, p=.0388), and central (95 vs. 109 µm, p=.0005) ONH subfields when compared with controls; and significantly thinner RNFL in the nasal (66 vs. 76 µm, p = .0293) and central (95 vs. 103 µm, p = .0179) ONH subfields when compared with Group 2. There were no significant differences in any ONH subfields between Group 2 and controls.
Conclusions: :
Sickle cell patients with focal macular thinning on SDOCT have significantly thinner RNFL on SDOCT than those without macular thinning and controls. These patients may require different RNFL thickness thresholds for future glaucoma evaluations. Further studies using perimetry will help determine whether these RNFL changes are visually significant and whether they would affect glaucoma evaluations.
Keywords: nerve fiber layer • retina • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)