Abrupt termination of photoreceptor mosaic at lesion borders in choroideremia is contrasted to gradual loss of photoreceptors in retinitis pigmentosa.

<p>Images from a subject with X-linked choroideremia (JC_0778, <b>top</b>) are compared with images from a previously-published[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0167526#pone.0167526.ref032" target="_blank">32</a>] subject with retinitis pigmentosa (DH_10161, <b>bottom</b>). To facilitate comparison, images of the same modality share the same scaling. Labeled <b>arrowheads</b> in OCTs correspond to respectively labeled AOSLO images, and imaged regions are selected to correspond to pathologic features. Panels <b>A</b> and <b>E</b> show 0.25 x 0.25° (approximately 74 x 74 μm) areas of retina with intact IZ and EZ bands on SD-OCT. In both pathologies, cone inner segments appear grossly normal on split-detector (<b>A</b>_<b>2</b><b>, E</b>_<b>2</b>), while only RP displays notably dim or dark cones on confocal (<b>E</b>_<b>1</b>). Panels <b>B</b> and <b>F</b> show areas of retina with IZ band dropout but intact EZ. Confocal AOSLO in both (<b>E</b>_<b>1</b><b>, F</b>_<b>1</b>) shows some irregular “multimodal” reflectivity, with dark cones again visible in the RP subject (<b>F</b>_<b>2</b>). Split-detector imaging (<b>E</b>_<b>2</b><b>, F</b>_<b>2</b>) again shows relatively normal inner segments. Panels <b>C</b> and <b>G</b> correspond to IZ and EZ dropout. In choroideremia, EZ dropout coincides closely with the loss of the ELM and presence of an interlaminar bridge (ILB). On AOSLO, there is an abrupt termination to the photoreceptor mosaic (<b>C</b>_<b>2</b>), with no cone inner segments present past this point (<b>D</b>_<b>2</b>). In RP, ILBs are generally not seen, and the ELM continues well past EZ dropout. On AOSLO, remnant cone inner segments similarly persist well past the end of the EZ (<b>G</b>_<b>2</b>), finally disappearing at or near the point of ELM termination (<b>H</b>_<b>2</b>). <b>Scale bars: OCTs,</b> 100 μm lateral, 100 μm axial; <b>AO,</b> 10 μm.