Quantitative evaluation of retinal microvasculature and retrobulbar vessels after intravenous chemotherapy for retinoblastoma

BACKGROUD: To evaluate the changes in retinal microvasculature and retrobulbar blood flow, using optical coherence tomography angiography (OCTA) and Color Doppler imaging (CDI) after intravenous chemotherapy (IVC) in patients with retinoblastoma (RB). METHODS: This was a retrospective comparative case control series involving 30 patients. Ten bilateral RB patients that had a preserved eye with extramacular tumours (group I), 10 unilateral RB treated with IVC that had a normal fellow study eye (group II), and 10 age-matched healthy controls. The macular retinal thickness, foveal avascular zone (FAZ) area, and the macular and peripapillary retinal vessel densities (RVD) were measured. The peak systolic and end diastolic velocities of the ophthalmic, central retinal and posterior ciliary arteries were determined. A comparison among the three groups was conducted. RESULTS: Between the three cohorts, OCTA revealed no significant difference in FAZ area, superficial foveal and parafoveal RVD, deep parafoveal RVD and peripapillary RVD, (P > 0.05). By contrast, the mean deep foveal RVD, the full, inner and outer foveal and the parafoveal retinal thickness were significantly lower in group I compared with the controls, (P = 0.0329, 0.0153, 0.0311 0.0352, 0.0215). No significant difference in the blood flow velocities occurred in the retrobulbar circulation (P > 0.05). CONCLUSIONS: In patients with retinoblastoma, OCTA did not detect significant changes of retinal thickness and vessel density in the eyes treated with IVC, but a slight reduction in retinal thickness and the deep foveal RVD seemed to occur in bilateral RB eyes. The retrobulbar blood flow parameters showed no measurable changes.