Central macular splaying and outer retinal thinning in asymptomatic sickle cell patients by spectral-domain optical coherence tomography

Abstract

Purpose: To investigate the prevalence and degree of macular thinning on optical coherence tomography (SDOCT) in African-American female patients with asymptomatic sickle cell disease.

Design: Prospective comparative case series.

Methods: Twenty-one sickle cell patients (42 eyes) without other systemic or ocular diseases and 18 healthy control patients (33 eyes) underwent SD-OCT. Images were manually segmented to measure inner retinal thickness (IRT) and outer retinal thickness (ORT). Central macular (central 1 mm), parafoveal (0.5-1.5 mm eccentricity), and perifoveal (1.5-3 mm eccentricity) thickness measurements were obtained in sickle cell patients and age/gender/race-matched healthy control subjects.

Results: Central macular total thickness (CMT) in sickle cell patients was 220 ± 3 μm (mean ± SEM), which was significantly lower (P < .05) than controls (228 ± 3 μm). Parafoveal regions had thickness measurements of 314 ± 5 μm (nasal) and 304 ± 2 μm (temporal), which were significantly lower than controls (327 ± 2 μm and 311 ± 2 μm nasally and temporally, respectively) (P < .03, P < .043). There was also no significant difference in IRT in central macula, parafoveal, and perifoveal regions. Central macular ORT was 175 ± 2 μm vs 185 ± 1 μm in controls (P < .0002). ORT in temporal parafoveal and perifoveal regions was 142 ± 2 μm and 120 ± 1 μm, respectively, vs 150 ± 1 μm and 122 ± 1 μm in controls (P < .001 and P = .16, respectively).

Conclusions: Manual segmentation of SD-OCT images revealed significant total retinal thinning in the central macula and splaying in asymptomatic sickle cell patients. Retinal thinning was predominately in outer retinal layers in central macula and parafoveal regions.

Figure 1

Spectralis OCT scan of a healthy control patient (Top Panel) displaying manually drawn boundary lines (Bottom Panel), at the inner limiting membrane (ILM), posterior nerve fiber layer (NFL), posterior outer plexiform layer (OPL) and at the retinal pigment epithelium (RPE) interface. The inner retinal thickness (IRT) and outer retinal thickness (ORT) are as labeled. The central subfield (central 1 mm diameter), parafoveal region (0.5 to 1.5 mm eccentricity) and perifoveal region (1.5 mm to 3 mm eccentricity) are labeled (Top Panel).

Figure 2

Spectralis OCT scan of a sickle cell patient (Top Panel) displaying manually drawn boundary lines (Bottom Panel). Note the presence of foveal splaying (outlined by asterisks) as well as focal thinning in the temporal macula (arrow).

Figure 3

Mean total retinal thickness in healthy control subjects (white bar) and sickle cell patients (gray bar). Thickness was averaged among the central subfield (central 1mm diameter), parafoveal (0.5 to 1.5 mm eccentricity) and perifoveal (1.5 mm to 3 mm eccentricity) regions. Error bars represent standard error of the means. (*) denotes p < 0.05.

Figure 4

Mean inner retinal thickness (IRT) in healthy control subjects (white bar) and sickle cell patients (gray bar). Thickness was averaged among the central subfield (central 1 mm diameter), parafoveal (0.5 to 3 mm eccentricity) and perifoveal (3 mm to 6mm eccentricity) regions. Error bars represent standard error of the means.

Figure 5

Mean outer retinal thickness (ORT) in healthy control subjects (white bar) and sickle cell patients (gray bar). Thickness was averaged among the central subfield (central 1mm diameter), parafoveal (0.5 to 3 mm eccentricity) and perifoveal (3 mm to 6 mm eccentricity) regions. Error bars represent standard error of the means. (**) denotes p < 0.01.