Rate-Distortion optimization is updated to improve HEVC coding performance for HDR content. The proposed method employs Perceptually Uniform encoding as a distortion measure and shows on average performance improvement of 1.06% for HDR-VDP-2.2 Q factor and 4.02% in HDR-VQM with respect to the reference encoder. Further, with proposed change, better bit budget estimation is achieved showing performance improvement in Rate-Control. In comparison to NRMSE values from 0.5991 to 3.7670 achieved by the reference encoder, the proposed method is able to achieve improved NRMSE values from 0.2896 to 2.7754.