Abstract
Purpose :
Vitreous inflammation in uveitis is challenging to quantify clinically due to its heterogenous nature and lack of objective grading systems. Our study aims to introduce the Vitreous Dot Index (VDI), a novel, objective marker of vitreous inflammation, to address the difficulties in such assessments.
Methods :
We performed optical coherence tomography (OCT) scans on 62 eyes (43 healthy and 19 uveitic) and used a purpose-built, semi-automated software to segment them. The VDI was calculated using an image binarization tool, determining hyper-reflective dots on OCT images (VDI-N) and their area (VDI-A) within segmented vitreous zones: zone III (anterior vitreous), zone II (middle vitreous), and zone I (posterior vitreous). Results, interpreted by two trained independent graders, were compared for inter-grader reliability using the intraclass correlation coefficient (ICC) and Bland-Altman plot analysis. We also hypothesised that VDI markers would exhibit higher values in the uveitis group, tested through an independent student’s t-test.
Results :
The ICC between graders for VDI-N for the control group revealed the following values for zone III, zone II, zone I, and total vitreous (TV): r=0.37 (p<0.001), r=0.79 (p<0.001), r=0.91 (p<0.001), and r=0.91 (p<0.001), respectively. In the uveitis group, the ICC between graders for VDI-N in the corresponding vitreous compartments were r=1.00 (p<0.001), r=0.84 (p<0.001), r=0.92 (p<0.001), and r=0.92 (p<0.001).
However, ICC between graders for VDI-A values showed substantial variability in both control and uveitis groups across all vitreous compartments, indicating agreement levels ranging from poor to excellent. Using independent student’s t-test, all mean VDI-N values were higher in the uveitis group, while mean VDI-A values were highly variable. However, results were statistically insignificant (p-values > 0.05) for both VDI-N and VDI-A markers.
Conclusions :
Inter-grader agreement for VDI-N values was consistently good to excellent, but VDI-A values showed considerable variability among graders in segmented vitreous compartments. Higher mean VDI-N values in the uveitis group implies a potential association with vitreous inflammation, but the lack of statistical significance necessitates further investigation. Additional research is crucial to understand further clinical implications and the VDI’s role in assessing vitreous inflammation in uveitis.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.