Abstract
Purpose: :
1) To determine the rates of focal retinal thinning in sickle hemoglobinopathy genotypes SC, SS, and SThal by SDOCT;2) To determine the relationship between focal retinal thinning detected by SDOCT and the stage of sickle retinopathy;3) To determine the pattern of macular subfield thickness changes in sickle hemoglobinopathy eyes relative to controls using SDOCT.
Methods: :
Prospective, comparative, observational study. Sickle hemoglobinopathy patients of genotypes SC, SS, and SThal and age and race similar control patients were scanned by SDOCT (Spectralis, Heidelberg Engineering). Focal retinal thinning was identified as an abrupt, asymmetric decline in total retinal thickness on SDOCT colorimetric map and confirmed on Bscan. Rates of focal retinal thinning were determined per patient genotype, eye genotype, and per eye stratified by stage of sickle retinopathy. Statistically significant differences in macular subfield thicknesses (using ETDRS-like subfields) between sickle hemoglobinopathy eyes and control eyes were calculated.
Results: :
92 sickle hemoglobinopathy patients and 28 control patients were imaged. Focal retinal thinning occurred in59% (16 of 27) of SC patients,59% (33 of 56) of SS patients,67% (6 of 9) of SThal patients and in51% (92 of 182) of all sickle hemoglobinopathy eyes.Focal retinal thinning generally increased with stage of sickle retinopathy. With all genotypes combined, focal thinning occurred in22% (4 of 18) of Stage 0 (no retinopathy) eyes,24% (4 of 17) of Stage 1 eyes,49% (48 of 97) of Stage 2 eyes,65% (24 of 37) of Stage 3 eyes,90% (9 of 10) of Stage 4 eyes, and100% (3 of 3) of Stage 5 eyes.Variable patterns of macular subfield thinning were found among the SC, SS, and SThal genotypes relative to controls. SC eyes were significantly thinner than controls in the temporal parafoveal and perifoveal subfields. SS eyes were significantly thinner than controls in all macular subfields. SThal eyes were significantly thinner than controls in all parafoveal and perifoveal subfields.
Conclusions: :
Focal retinal thinning detected by SDOCT is a common finding in sickle hemoglobinopathy patients of genotypes SC, SS, and SThal and increases in frequency with increasing stage of sickle retinopathy. Variable patterns of macular subfield thinning are seen in the different genotypes and likely reflects the variable severity of ischemia induced by each genotype as well as the watershed zones of the macula.
Keywords: vascular occlusion/vascular occlusive disease • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: prevalence/incidence