Image characteristics and quantitative analysis of multicolor imaging in eyes with cystoid macular edema

Objective To observe the imaging features of cystoid macular edema (CME) in multicolor imaging (MC), and to evaluate the value of MC in the diagnosis of CME. Methods Descriptive case series study. From August 2017 to June 2018, 42 eyes of 37 patients with CME diagnosed in the people's Hospital of Wuhan University were included in the study. Among them, there were 24 males and 13 females, with an average age of 48.51±10.29 years. There were 14 eyes with diabetic retinopathy, 14 eyes with central retinal vein occlusion, 8 eyes with branch retinal vein occlusion, 4 eyes with uveitis, and 2 eyes with Eales disease. The macular color fundus photography (CFP) was performed with Visucam 200 non-mydriatic fundus camera of Zeiss company in Germany. MC, frequnce domainoptical OCT (SD-OCT) and FFA were examined by Spectralis HRA2 + OCT of Heidelberg company in Germany. According to the MC standard method, five images, including 488 nm blue reflection (BR), 515 nm green reflection (GR), 820 nm infrared reflection (IR) imaging and standard MC and blue-green enhancement (BG), were obtained at the same time. Compared with SD-OCT, CFP and MC images were scored. Friedman M test and Wilcoxon signed rank test were used for statistical analysis. Results The standard MC and BG images showed blue-green uplift area or petal-shaped appearance, surrounded by green reflection areas with clear boundaries. BR image can be seen in the low reflexes area. On the GR image, there were patches or cystic low reflection areas, surrounded by a slightly high reflection. On the IR image, patches or cystoid high reflexes can be seen, surrounded by low reflection dark areas with clear boundaries. The average scores of CFP, standard MC, GB, IR, GR and BR were 1.20±0.94, 3.05±0.99, 2.90±1.04, 2.55±1.27, 2.00±0.94, 0.51±0.85 respectively, and the differences were statistically significant (χ2= 151.61, P=0.000). The score of CFP were significantly lower than that of standard MC (Z=-5.421), BG (Z=-5.354), IR (Z=-4.714), GR (Z=-4.438) and higher than that of BR (Z=-3.435). The differences were statistically significant (P=0.000, 0.000, 0.000, 0.000, 0.001). Conclusions The quality of MC imaging is better than that of CFP. Combined with SD-OCT, it can be used as an assistant method to diagnose CME. Key words: Macular edema/diagnosis; Tomographyoptical coherence; Fluorescein angiography; Multicolor imaging