CILIORETINAL ARTERIES IN DIABETIC EYES ARE ASSOCIATED WITH INCREASED RETINAL BLOOD FLOW VELOCITY AND OCCURRENCE OF DIABETIC MACULAR EDEMA GENNADY LANDA, MD,*† WENDEWESSEN AMDE, MD,* YODIT HAILESELASSIE, BA,* RICHARD B. ROSEN, MD*† Purpose: The main purpose was to investigate the relationship between occurrence of cilioretinal arteries and macular edema in diabetic eyes in terms of retinal blood flow characteristics revealed by the Retinal Function Imager (RFI). Other standard imaging techniques such as fundus photography, fluorescein angiography, and spectral-domain optical coherence tomography/scanning laser ophthalmoscopy were also used along with the RFI. The additional purpose was to look for the evidence of cilioretinal–retinal collaterals using the RFI. Methods: Patients with a diagnosis of diabetic retinopathy were included. All patients underwent fundus photography, fluorescein angiography, spectral-domain optical co- herence tomography, and imaging using RFI. The presence of cilioretinal artery (CilRA) was recognized using color/red-free fundus photographs, fluorescein angiography, and RFI. There were two groups according to the presence (CilRA group) or absence (NoCilRA group) of cilioretinal artery or arteries in the study eye. Results: Thirty-nine eyes with diabetic retinopathy were included. Cilioretinal artery was identified in 15 eyes (38%). In the CilRA group, spectral-domain optical coherence tomography evidence of macular edema was observed in 13 of 15 eyes (87%), whereas in the NoCilRA group, macular edema was observed on spectral-domain optical coherence tomography in 7 of 24 eyes (29%). Mean blood flow velocities in retinal arteries and veins were significantly higher in diabetic eyes with cilioretinal artery (P = 0.04 and P = 0.005, respectively). Mean blood velocity in cilioretinal arteries was significantly higher in comparison with the mean arterial blood velocity (P = 0.03). In the CilRA group, cilioretinal– retinal collaterals, assessed by RFI, were detected in 4 of 15 eyes (27%) with cilioretinal arteries. In the NoCilRA group, mean blood velocity in retinal veins was significantly higher in eyes with macular edema in comparison with those without macular edema (P = 0.03). Conclusion: Using the RFI in conjunction with standard fundus imaging techniques, the presence of cilioretinal artery in diabetic eyes was found to be associated with increased retinal blood flow velocity and increased occurrence of diabetic macular edema. The occurrence of cilioretinal–retinal collaterals was also noted; however, the pathophysiologic significance of this finding requires further investigation. RETINA 31:304–311, 2011 A single cilioretinal artery (CilRA) or, more rarely, multiple cilioretinal arteries can originate from the short posterior ciliary arteries or directly from the choroidal circulation and usually emerge at the temporal margin of the optic disk. CilRA can be demonstrated during the choroidal flush phase of fluorescein angiography (FA) when fluorescein appears in CilRA before its appearance in the proximal branches of the central retinal artery. The reported incidence of the cilioretinal artery varies among published literature, ranging between 6% and 40%. 1–8 Since the 19th century, there has been extensive controversy in the literature regarding the relationship of these vessels to the retinal circulation and their 304