Adaptive Optics Imaging to Analyze the Photoreceptor Layer Reconstitution in Acute Syphilitic Posterior Placoid Chorioretinopathy

Acute posterior syphilitic placoid chorioretinopathy (ASPPC) is a rare ocular manifestation of syphilis characterized by outer retinal layers involvement and drop in visual acuity. The current work documents outer retinal layer involvement in this pathology and their reconstitution with treatment by means of adaptive optics (AO). Three eyes of two patients together with four controls eyes were included in the study. Patients underwent optical coherence tomography (OCT) and OCT angiography (OCTA) scan centered on fovea, where vessel density (VD) and vessel perfusion (VP) were calculated. AO images centered on fovea were acquired and cone density (CD) and cone spacing (CS) were measured and compared to control group. Multimodal imaging was performed at presentation, at 10 days, and at 2-month follow-up. All eyes improved in visual acuity, with reconstitution in outer retinal layers at 2-month follow-up. Overall choriocapillary layer VD and VP improved. AO imaging was able to identify outer retinal alterations at presentation and at follow-ups, with improvement in tissue architecture. CD and CS was respectively lower and greater than controls at all follow-ups and improved within patients at the 2-month follow-up. In conclusion, AO was able to document outer retinal alterations in ASPPC at presentation and improvement over the follow-up, representing a tool to study photoreceptor layer involvement in this pathology.