Intraretinal hyperreflective foci on spectral-domain optical coherence tomographic images of patients with retinitis pigmentosa

Background: The purpose of this study was to observe the characteristic findings of spectral-domain optical coherence tomography (SD-OCT) images in the retinas of patients with retinitis pigmentosa and to evaluate their distribution patterns in the early and advanced stages of the disease. Methods: A total of 184 patients (368 eyes) with retinitis pigmentosa were observed using SDOCT. We studied the presence or absence of continuous inner/outer segment (IS/OS) lines, presence of thinning of the retinal pigment epithelium-Bruch's membrane complex, and distribution patterns of hyperreflective foci in the inner and outer nuclear layers (INL and ONL). Results: The IS/OS junction had partially disappeared in 275 eyes, which were at the early stage of retinitis pigmentosa (group X), whereas the junction had totally disappeared in 93, which were at the advanced stage of retinitis pigmentosa (group Y). Hyperreflective foci in the INL were observed in a significantly larger proportion of the eyes in group X than in group Y (90% versus 61%, P<0.001), but hyperreflective foci in the ONL were observed in a significantly larger proportion of eyes in group Y than in group X (100% versus 69%, P<0.001). Conclusion: Hyperreflective foci in the INL were more frequently observed in retinas with the early stage of retinitis pigmentosa and hyperreflective foci in the ONL were more frequently observed in the advanced stage. Hyperreflective foci may be indicative of changes in the retinal structure at each stage of retinitis pigmentosa.