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

Abstract

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.

Keywords: acute syphilitic posterior placoid chorioretinopathy; adaptive optics; optical coherence tomography; optical coherence tomography angiography; syphilis; uveitis.

Figure 1

Improvement in the right eye of Patient 1 at optical coherence tomography (OCT), fundus autofluorescence (FAF) and fundoscopy from presentation (A–C), to 10 days follow-up (D–F) to 2 months after treatment (G–I). Borders at the placoid lesion become more defined and slowly fade with decreasing hyper-autofluorescence. In this eye external limiting membrane and ellipsoid zone which were disrupted at presentation, recovered their morphology, together with improvement at FAF.

Figure 2

3 × 3 mm optical coherence tomography angiography (OCTA) choriocapillary layer density map (A,D), image reconstruction (B,E), and ETDRS chart density map (C,F) of right eye of Patient 1. Over the 2-month follow-up we see an improvement of flow voids identifiable at presentation.

Figure 3

Progressive improvement in tissue architecture with adaptive optics. The top 3 yellow squares depict the right eye of Patient 1 at time of patient presentation (A), and along follow-up at 10 days (B) and 2 months (C). At presentation, defined dark patchy areas were present, representing outer retinal tissue disorganization (yellow dashed rectangle), while these areas decrease in extension and number, with partial tissue architecture restoration. It also shows adaptive optics Imaging analysis in patients eyes (D–G) and controls (H–K). Cone density (CD) and spacing (CS) analysis were measured in regions of interest at 1.5 degrees from foveal center (red square), and individual cones could be quantitatively estimated.

Figure 4

Tissue architecture improvement with adaptive optics. The top 3 squares depict the left eye of Patient 2 at time of patient presentation (A), and at follow-up of 10 days (B) and 2 months (C). At presentation, tissue disorganization (dashed rectangle) with architecture restoration over the follow-up was shown. Images also show the difference between the unaffected right eye of Patient 2 (D) compared to the affected left eye (E) 3 months after therapy initiation. Although visual acuity recovered completely, the tissue remained partially disorganized, with slight presence of dark patchy areas not present in the fellow eye. The bottom images (F,G) show the affected left eye at presentation and at 3-month follow-up. At 3 months (G), there is complete reconstitution of outer retinal layers, with only a slight granular appearance of ellipsoid zone, which corresponds to damage seen at adaptive optics.

Figure 5

Highlights the correspondence between 3 mm × 3 mm optical coherence tomography angiography (OCTA) choriocapillary (CC) images (A,E) and OCTA vessel density map (B,F) with adaptive optics images at the foveal level (C,G). Images (A–D) refer to patient at presentation, while images (E–H) at 2-monthsfollow-up. Tissue architecture disruption corresponds to area of decreased vessel density (D) at OCTA, while tissue partial recovery at 2-month follow-up corresponds to decrease in flow-void areas at the CC level (H).