Complex interventions to implement a diabetic retinopathy care pathway in the public health system in Kerala: The Nayanamritham study protocol by Sivaprasad, S, Netuveli, G, Wittenberg, R, Khobragade, R, Sadanandan, R, Gopal, B, Premnazir, L, Conroy, D, Srinath, J, Ramakrishnan, R, George, S, Sahasranamam, VI