Study of Arteriovenous Crossings of Retinal Vasculature in Relation with Abo Blood Grouping in 500 Normal Subjects

In an attempt to find out whether any relation exists in between the arteriovenous crossings of retinal vasculature and the blood group of a person, we compared the database of vein posterior to artery (VPA) and vein anterior to artery (VAA) with the persons blood group in 500 normal subjects. Fundi of both the eyes were dilated in normal subjects and retinal photographs were taken with the fundus camera. Each eye was divided into four Quadrants- the Superotemporal, Inferotemporal, Superonasal and Inferonasal. Vessels were distinguished on the basis of colour, central reflux, and diameter. Subjects having any systemic disease like hypertension, diabetes, and with any anomaly of the eye or face were excluded from the study. We did not include subjects below 18 years and above 40 years of age. We compared the database (percentage, frequency) of arterial overcrossings (VPA) and venous overcrossings (VAA) with the blood group of subjects in all the four quadrants of both the eyes. Based on our study we found p=0.027 in the Superonasal quadrant of left eye for arterial overcrossings. In rest all the quadrants of both eyes, p value was non significant. Statistically, the Superonasal quadrant of left eye was found to have more frequency of two Arterial Overcrossings (n1=2) in the AB+ blood group than any other blood group studied. A more reliable data can possibly be obtained by increasing the number of subjects.