The research aims to get a higher resolution structure of the retinol binding protein 3 which is an essential protein in visual cycle. The major goal of the project is to propose a new diagnostic method in the field of Diabetic Retinopathy (DR). The current treatment methods for DR are invasive and lead to several post-treatment risks, i.e., mild loss of central vision, decreased ability to focus, etc. So, the demand for the proposed TPEF scenario is to introduce a technique for early diagnosis and a way to follow treatment efficacy in a non-invasive manner. Two-photon microscopy and detection/quantification of RBP3 at an early level could be a ray of hope in the development of new therapeutic approaches for Diabetic Retinopathy and many other ocular complications. The proposed method to detect the RBP3 protein in a non-invasive manner will address the current limitations of this field.