Phenotypic Characterization of Choroidal Neovascularization in Pachychoroid Spectrum Using Multi-modal Imaging

Abstract

Purpose : Choroidal neovascularization (CNV) is a frequent complication and cause of reduced vision in the pachychoroid spectrum diseases, especially chronic central serous chorioretinopathy(CSC) wherein the definitive diagnosis of CNV is often challenging. In our study, we are describing the diagnostic features of different CNV phenotypes developed in the pachychoroid spectrum over long term follow up period using multi-modal imaging

Methods : This is a retrospective study included patients who had been diagnosed with CNV secondary to CSC between June 2008 and July 2019 at Moorfields Eye Hospital (MEH). Patient demographics, clinical and photographic data were collected and reviewed. The presence of CNV was confirmed by any of this modality; fluorescein angiography, Indocyanine green angiography, or OCT Angiography. OCT B-scans were analysed for the choroidal thickness, the presence of intraretinal fluid (IRF), subretinal fluid (SRF), and subretinal hyperreflective material (SHRM). The retinal pigment epithelium (RPE) was evaluated for the presence of micro RPE tear or pigment epithelium detachment (PED). The PED was classified into round or flat irregular PED. In the flat irregular type, the reflectivity of the sub-RPE space was also characterized as totally or partially hyperreflective, or hyporeflective.

Results : A total of 514 patients had been presented to MEH with CSC. Of those,147 eyes of 129 patients developed CNV. Their mean age at CNV development was 65.9 ± 9.11 years and the mean follow up period was 51.47 months. Three types of neovascularization were detected with a different diagnostic features on OCT. Type 1 CNV: flat irregular PED was detected in 94 eyes (64%) with either underlying total hyperreflectivity (78%) or partial hyperreflectivity (22%). A small polyp was detected at the edge of the PED In 38 eyes (40%) of this group. Type 2 CNV was detected in 22 eyes (15%). All of them are characterized by the presence of small PED with micro RPE tear and SHRM. The third group of patients (31 eyes, 21%) were diagnosed with polypoidal choroidal vasculopathy (PCV), featuring large polyps with their typical OCT characteristics (Figure 1&2).

Conclusions : CNV secondary to the pachychoroid spectrum has several phenotypes with a tendency to overlap at some stages. Although challenging, a subclassifications of different CNV types is warranted, as it could influence the treatment decision

This is a 2020 ARVO Annual Meeting abstract.