Abstract
Purpose :
To investigate anatomical biomarkers that more accurately define the pachychoroid spectrum than central choroidal thickness (CCT) and choroidal vascular index (CVI).
Methods :
In 20 eyes each of 14 patients with CSCR and 14 age- and gender-matched controls, we measured CCT at 11 pre-determined points (foveola, 500 μm, 1000 μm, 1500 μm, 2000 μm, 2500 μm nasal and temporal to foveola), as well as CVI in the 1500 μm and 5000 μm subfoveal areas using optical coherence tomography (OCT) scans. ImageJ was used to stratify scans into Haller and non-Haller layers, and to measure the CVI and CCT of each layer. SPSS IBM version 28 was used to perform Student’s t-test to compare data between the CSCR group and controls.
Results :
CVI of the Haller layer (CSCR: 64.2 ± 2.42 μm vs. controls: 63.0 ± 2.64 μm; p=0.15) and the total choroidal area (CSCR: 64.8 ± 2.32 μm vs. controls: 65.4 ± 2.01 μm; p=0.42) was not significantly different in the 5000 μm area. Within the 1500 μm subfoveal area, CVI of the Haller layer was higher in the CSCR group (63.79 ± 2.70 μm vs. 61.96 ± 1.40 μm in controls; p=0.01), and the CVI of the non-Haller layers was lower in the CSCR group (66.55 ± 11.68 μm vs. 74.96 ± 7.71 μm in controls; p=0.01). There was no difference in the foveolar CCT of the choroid (CSCR: 274.4 ± 79.7 μm vs. controls: 262.8 ± 77.0 μm; p=0.64). Stratified analysis revealed that while the foveolar CCT of the Haller layer was also similar between the two groups (CSCR: 219.0 ± 75.9 μm vs. controls: 219.5 ± 78.4 μm; p=0.99), the foveolar CCT in the non-Haller layers was significantly higher in the CSCR group (60.1 ± 23.3 μm vs. 46.8 ± 13.0 μm in controls; p=0.03).
Conclusions :
CVI and CCT analysis showed that in CSCR, there is an expansion of the vascular area in the Haller layer at the cost of the stromal matrix, and compressive closure of the inner choroidal vasculature with subsequent replacement by fibrous tissue. Thus, the term “Pachy-Haller” more accurately defines this group of diseases previously termed “Pachychoroid”.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.