Purpose: To determine the rate of retinal thinning on spectral-domain (SD) OCT in patients with sickle cell compared with controls. Design: Retrospective, longitudinal study. Participants: Patients with sickle cell and age-similar control patients with SD-OCT macula volume scans at least 10 months apart were reviewed. Methods: Automated segmentation of the SD-OCT macula volume scans was performed using the Iowa Reference Algorithms to divide the retina into 3 combined retina layers: superficial (retinal nerve fiber layer and ganglion cell layer), middle (inner plexiform layer and inner nuclear layer), and outer (outer plexiform layer to retinal pigment epithelium). The mean retinal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield was recorded. The rate of retinal thickness change was calculated using a multilevel mixed-effects model. Main Outcome Measures: The rate of retinal thickness change in the superficial, middle, and outer retina. Results: Thirty-eight eyes of 24 patients with sickle cell (age: mean 40 years, range 18–67 years; genotype: 12 hemoglobin SS, 11 hemoglobin SC, 1 not available) and 30 eyes of 30 control patients were followed on average for 25.5 months. The mean initial retinal thickness was thinner in the sickle cell group compared with the control group (superficial: 69.95 vs. 72.22 μm; middle: 65.24 vs. 71.22 μm; outer: 171.37 vs. 175.55 μm). The mean rate of retinal thinning was greater for the sickle cell group than the control group (superficial: −0.89 vs. −0.41 μm/year; middle: −0.45 vs. +0.18 μm/year; outer: −0.50 vs. −0.02 μm/year). The rate of thinning in patients with sickle cell was statistically significant (P < 0.05) for the superficial retina in the center subfield and nasal and temporal inner subfields, as well as the middle retina in the temporal inner subfield. Compared with controls, there was a faster rate of retinal thinning for the middle retina in the temporal inner subfield. Rates of retinal thinning were similar regardless of whether qualitative areas of focal retinal thinning were seen on initial imaging. Conclusions: Patients with sickle cell exhibit a progressive retinal thinning predominantly affecting the superficial and middle retina that may represent chronic microvascular insult.
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