Fundus fluorescein angiography database were segregated to identify people with diabetes and CRA at three tertiary care centers in south India. On screening database from 2015 to 2017, a total of 43 (26 men and 17 women) patients were identified at various stages of diabetic retinopathy with presence of CRA. Out of which unilateral CRA was present in 40 patients and bilateral CRA in 3 patients. All the patients in the study group had adult-onset diabetes mellitus with mild-to-severe non proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). Patients with neovascularization of the disc (NVD) and small fine cilioretinal artery at the disc margin on angiogram were excluded.
The demographic details and medical history including duration of diabetes-associated systemic hypertension were noted. The treatment received, including LASER and intravitreal injections and visual acuity, was noted. Fundus photos were graded for the presence of diabetic retinopathy using ETDRS classification. Classification of DME is based on ETDRS subfields on OCT.
FFA-proven CRA side and prominent regions of the macula (upper, central, and lower) being supplied by it were noted. OCT images were taken in Cirrus SD-OCT and the findings were entered carefully as center-involving DME, non center-involving DME, no DME, presence of epiretinal membrane and/or taut posterior hyaloid membrane causing traction on macula and thinning suggestive of atrophy. Possible presence of CRA in the other eye was also noted. The study was approved by the Institutional Review Board (Ethics committee), Vision Research Foundation and written consent was obtained from the subjects as per the Declaration of Helsinki.
Grading of DME
The grading of DME was done as follows: 
Center-involving DME: On clinical examination, definite retinal thickening due to DME involving the center of the macula. The spectral-domain optical coherence tomography (SD-OCT) showed loss of foveal contour, cystic space involving center of fovea, and neurosensory detachment involving the center of fovea. Central subfield thickness on OCT > 290 μm for women, >305 μm for men was observed on SD-OCT (Cirrus; Zeiss).
Non center-involving DME: Definite retinal thickening due to DME within 3000 μm of the center of the macula but not involving the center of the macula. The SD-OCT showed cystic spaces and or retinal thickening in non central macular subfields.
No DME: Normal central subfield thickness on OCT 209±18 μm in men and 194±23 μm in women.
Mean Retinal thickness (in microns) according to Early-Treatment Diabetic Retinopathy Study (ETDRS) protocol .
Clinically significant macular edema is considered if the retinal thickening or hard exudates are observed within 500 ± 50 μm of the center of the foveal avascular zone or zones of retinal thickening 1 disc area or larger, any part of which was within 1 disc diameter of the center of the macula . Hence the identification of DME is based on both specific OCT features and retinal thickness was taken into consideration.
Descriptive statistics was used to analyse the baseline characteristics. For statistical analysis of groups and subgroups, an independent sample t-test was used. Relationship of diabetic macular edema were calculated as proportions of each area of supply by cilioretinal artery. Relationship between area of supply of cilioretinal artery and area of retinal thickness were analysed to report mean and standard deviation in each quadrant of the retina and Chi square test was used to find the Distribution of diabetic macular edema with presence and absence of cilioretinal artery.