The second in our series of articles examining precise refraction focuses on dioptric sensitivity among patients. It includes the outcomes of a study which shows that 95% of patients are sensitive to dioptric increments lower than 0.25 diopter and 44% to increments lower than 0.125 D. These results were the origin of Essilor’s initiative to develop new refraction solutions for precise refraction in 0.01 D steps and to make available the corresponding range of ophthalmic lenses.