PRRT2 and Duane retraction syndrome: While the initial results of the multicenter randomized trial from the Protein Kinase C β Inhibitor Diabetic Retinopathy Study (PKC-DRS) group noted no statistically significant effect of ruboxistaurin at any of the three treatment doses for the progression of DR by their primary outcome measurements after a minimum followup of 3 years, they did note the effects of the PKC inhibitor on their secondary outcome, moderate visual loss (MLV), and sustained moderate visual loss (SMVL) [67].