Retinal Blood Vessel Tortuosity: Quantifying and Grading- A Review
Blood vessel tortuosity is utilized to detect various vascular and non-vascular diseases like diabetic retinopathy (DR), retinopathy of prematurity (RoP). Early detection and grading of these diseases could prevent further complications. Hence, the accurate detection and grading is paramount for this purpose. A good number researcher has proposed automated tortuosity grading algorithm based upon different methods of classification and grading. In literature, numerous definitions and measurement methods of tortuosity have been reported by different researchers. In this work, an attempt has been made to compare and discuss various automated and manual tortuosity measurement systems in terms of their merits and demerits. Further, a study has been carried out on different publicly available datasets and an attempt has also made to compare these data sets on the basis of size, variety and suitability of the vessels segment algorithm used in these data sets.