PMC8267582_01
Anterior segment photographs demonstrated mild grade corneal haze bilaterally (a). Fundus photography of the right and left eyes (b).
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The anterior segment examination demonstrated bilateral grade 2 corneal haze (Figure 1). Fundus examination was clinically normal (Figure 1).
SD-OCT horizontal and vertical scans of fovea in the right eye (a, b). It demonstrates foveal increased thickness of hyperreflective band signal at the ELM, with intact myoid, ellipsoid, and interdigitation zones, RPE, and Bruch's membrane. In the parafoveal and perifoveal region, it demonstrated a progressive loss of interdigitation and ellipsoid zones, myoid zone, and ELM and thinning of the outer nuclear layer. SD-OCT horizontal scan, close to the fovea (c), demonstrated a small cyst in ONL, INL, and GCL (arrows). SD-OCT: spectral domain optical coherence tomography; ELM: external limiting membrane; RPE: retinal pigment epithelium; ONL: outer nuclear layer; INL: inner nuclear layer; GCL: ganglion cell layer.
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The other outer retinal bands (the myoid, ellipsoid, and interdigitation zones, the retinal pigment epithelium (RPE), and Bruch's membrane) were within normal limits (Figure 2). In the parafoveal and perifoveal regions, SD-OCT displayed a loss of the interdigitation, ellipsoid, and myoid zones, loss of the ELM, and thinning and eventual loss of the outer nuclear layer (ONL) (Figure 2). The scans, close to the fovea, also revealed small cysts in the ONL, inner nuclear layer (INL), and ganglion cell layer (GCL) (Figure 2).
Fundus infrared imaging revealed hyperreflective ring centred in the fovea and hyporeflective areas in temporal parafoveal regions in both eyes (a, b). En face SD-OCT images at the level of the outer retina revealed two hyperreflective rings corresponding to the disruption of the ellipsoid zone (c, e) and ELM (d, f). SD-OCT: spectral domain optical coherence tomography; ELM: external limiting membrane.
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It also revealed hyporeflective areas in the temporal extrafoveal regions in both eyes (Figure 3). The inner ring corresponded to the limits of the disruption of the ellipsoid zone, and the external ring limits the disruption of the ELM on SD-OCT (Figure 3).
ERG findings. Absence of DA 0.01 ERG response and a DA 10.0 with a diminished a-wave and b-wave. LA 3.0 ERG with a diminished b-wave and absence of LA flicker 30 Hz ERG response. ERG: electroretinography; DA: dark-adapted; LA: light-adapted.
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The light-adapted (LA) 3.0 ERG had a diminished b-wave and absence of the LA flicker 30 Hz ERG response (Figure 4).