Abstract
Purpose :
Based on the possible role of chronic venous congestion exerted by “pachyvessels” in pachychoroid diseases, we initiated this study to explore quantitative differences in the choroidal stroma and vessel lumen area using enhanced depth imaging-optical coherence tomography (EDI-OCT) and studied their differences according to the types of pachychoroid diseases.
Methods :
Sixty six eyes of 66 patients (44 men and 22 women, mean age 49.1±14.9 years) including 21 chronic central serous chorioretinopathy(CSC), 14 pachychoroid pigment epitheliopathy(PPE), 17 pachychoroid neovasculopathy(PNV) (three pachychoroid groups), and 14 myopic CNV (mCNV group) were included. All patients underwent standard ophthalmological examination and EDI SD-OCT (Heidelberg Spectralis) was performed. Each EDI-OCT image was binarized with the ImageJ software and the area of lumen (dark pixels) and stroma (light pixels) were calculated. The examined area was 3000 μm wide in the subfoveal choroid centred on the fovea, and extended vertically from the outer border of the RPE to the choroid-scleral border. Central choroid thickness (ChT) and outer nuclear layer (ONL) thickness were manually measured using the caliper built in the Heidelberg software.
Results :
Central choroidal thickness was higher in three pachychoroid groups compared to mCNV group (430.0±98.4μm vs 213.2±89.9μm, P<0.001). There was no significant difference in ChT among three pachychoroid groups (P>0.075). The ratio of luminal to total choroidal area (L/C) was higher in CSC group compared to other groups (0.77±0.07 vs 0.70±0.02, 0.69±0.06, 0.68±0.08 for CSC, PPE, PNV, and mCNV, respectively, P<0.002). However, the ratio of stroma to total choroid area (S/C) was significantly lower in CSC group (0.23±0.07 vs 0.30±0.02, 0.31±0.06, 0.32±0.08, P<0.002). The ratio of stroma to luminal area (S/L) was also significantly lower in CSC group (0.31±0.12 vs 0.42±0.05, 0.45±0.11, 0.49±0.22, P<0.002). All three parameters of L/C, S/C, and S/L among other three groups were not statistically different. Thickness of ONL was reduced in CSC and PNV group compared to PPE or mCNV group (P<0.05).
Conclusions :
Eyes with CSC have significantly smaller areas of choroidal stroma compared to eyes with PPE, PNV or mCNV. The relatively small quantity of stroma in CSC eyes suggests that ‘chronic low-grade’ inflammation and subsequent tissue atrophy might be one of pathophysiology underlying this disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.