Abstract
Purpose:
To evaluate the choroidal circulation before and after panretinal photocoagulation (PRP) for diabetic retinopathy (DR).
Methods:
This study was conducted in 34 eyes of 26 patients. Choroidal blood velocity at the macula was evaluated as mean blur rate (MBR) by laser speckle flowgraphy (LSFG). PRP was performed using a pattern scanning laser (PASCAL). Choroidal blood velocity was imaged before and during PRP, and at monthly intervals for 6 months after PRP. Patients with prior PRP, vitrectomy, diagnosis of extensive vitreous hemorrhage or mature cataracts were excluded. LSFG was performed with a new external laser unit (wavelength, 830 nm) for wider illumination of the retina.
Results:
Mean choroidal velocity decreased to 79.6±15% (P<0.001) after PRP as measured by LSFG. PRP reduced choroidal circulation to 82.9±14%, 80.1±14% and 82.9±17% (P<0.001 each) at 1, 3 and 6 months after PRP, respectively, compared with before PRP. None of the present cases developed exacerbation of DR after PRP.
Conclusions:
Our previous reports have indicated that PRP reduces retinal blood flow to 71.2±15%, compared with initial value. In this study, choroidal circulation similarly reduced retinal blood flow after PRP. The number of laser spots correlated with decreases in mean blood velocity (R=0.31, p=0.021). LSFG may be useful for clarifying the optimal number of laser spots for DR. If adequate PRP was enforced, retinal blood flow and choroidal circulation decreased to 71% and 79% compared to before PRP.
Keywords: 499 diabetic retinopathy •
451 chorioretinitis •
585 macula/fovea