Tornado diagram for net monetary benefit usual care (usual care) versus intervention (early PRP). Tornado diagram for net monetary benefit usual care (usual care) versus intervention (early PRP). NPDR, non-proliferative diabetic retinopathy; OCT, optical coherence tomography; PDR, proliferative diabetic retinopathy; PRP, panretinal photocoagulation; PT, post-treatment; WTP, willingness to pay. Hema Mistry et al. BMJ Open Ophth 2017;2:e000021 © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2016. All rights reserved. No commercial use is permitted unless otherwise expressly granted.