Abstract
Purpose :
Sickle cell retinopathy can result in macular changes detectable on spectral domain optical coherence tomography (SD-OCT), including inner retinal thinning in the temporal macula. However, little is known about longitudinal macular changes in how these areas of thinning progress over time. This study evaluates the rate of retinal thinning as quantified by SD-OCT in patients with sickle cell disease.
Methods :
Sickle cell disease patients seen at the Wilmer Eye Institute with visits separated by at least 10 months were identified for retrospective review. SD-OCT volume scans centered on the fovea were obtained with the Spectralis HRA+OCT (Heidelberg Engineering). Automated segmentation of the individual retinal layers was performed using the Iowa Reference Algorithms (Retinal Image Analysis Lab, Iowa Institute for Biomedical Imaging, Iowa City, IA). The thicknesses of the inner retina (retinal nerve fiber layer and ganglion cell layer), middle retina (inner plexiform layer and inner nuclear layer), and outer retina (outer plexiform layer to the retinal pigment epithelium) were recorded for each of the 9 ETDRS subfields. The rates of retinal thickness change in the various subfields were calculated and compared across the various retinal layers using a multilevel mixed effects model.
Results :
Thirty-five eyes of 23 patients (genotype: 9 HbSS, 11 HbSC, 3 unspecified; gender: 10 male, 13 female) were included. Average age was 38 years (range 18 to 67 years). Mean follow up was 25 months (range 10 to 57 months). Thirteen eyes had discrete areas of pathologic thinning on OCT (genotype: 6 HbSS, 6 HbSC, 1 unspecified). There was loss of inner, middle, and outer retinal thickness at an average of 0.78 µm/year, 0.12 µm/year, and 0.59 µm/year, respectively. There was a statistically-significant decline in inner retinal thickness over the period of follow-up in the nasal and temporal inner subfields (P<0.02). When comparing the rate of retinal thinning across the retinal layers (inner, middle, and outer), no statistically-significant differences were found.
Conclusions :
Patients with sickle cell disease experience progressive thinning of the inner retina, especially in the horizontal subfields, that can be quantified over time using SD-OCT. Further study is needed to explore the clinical significance of the thinning and the role of factors such as sickle cell genotype on the rates of retinal thinning.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.