Abstract
Purpose: :
Laser speckle flowgraphy (LSFG) (LSFG-Navi, Softcare, Fukuoka, Japan) is a new instrument for measuring and mapping blood flow of the ocular fundus. We investigated the chorioretinal blood flow and observed the blood flow map using LSFG before and after intravitreal ranibizumab (IVR) injection in patients with choroidal neovascularization (CNV).
Methods: :
Twenty-three eyes of 23 patients (15 males and 8 females, mean age 70.0+/-11.7) with naïve CNV associated with typical age-related macular degeneration (12 eyes), polypoidal choroidal vasculopathy (5 eyes), pathological myopia (5 eyes) and idiopathic CNV (1 eye) were examined for the retinal blood flow at the optic disc and the chorioretinal blood flow at the macula using LSFG before and 1 month after each introductory IVR injection (one injection per month over 3 months) and evaluated using the mean blur rate (MBR).
Results: :
The central macular thickness significantly decreased from 447+/-200µm to 318+/-107µm, 296+/-120µm, 276+/-118µm after 1st, 2nd and 3rd IVR respectively (p<0.01, Dunnett test in all period). Compared to before the IVR, the average MBR of the blood flow in the main retinal vessels at the disc area slightly decreased after the 1st (94.5+/-15.7%), 2nd (95.7+/-14.7%) and 3rd (97.5+/-15.5%) IVR, but exhibited no statistically significant difference after each IVR (p=0.15, repeated measures ANOVA). The average MBR of the chorioretinal blood flow at the macula reduced significantly after the 1st (91.5+/-12.0%, p<0.05, Dunnett test) and 2nd (89.2+/-14.5%, p<0.01, Dunnett test) IVR, although the difference disappeared after the 3rd IVR (94.4+/-14.8%). The blood flow maps visualized by LSFG detected CNV in 10 cases and also observed the reduction in blood flow at the CNV lesion in 6 cases.
Conclusions: :
IVR indicated no significant difference in the retinal blood flow at the disc area, but significant decrease in the chorioretinal blood flow at the macula after the 1st and 2nd time. The difference in response to IVR between retinal main vessels and chorioretinal blood flow might be caused by the lack of a blood flow autoregulation system in the choroid. LSFG might be a valid measurement to evaluate the effect of treatment for CNV.
Keywords: choroid: neovascularization • imaging/image analysis: clinical • age-related macular degeneration