To improve the quality of the illumination distribution, one novel indoor visible light communication (VLC) system, which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflection-intelligent reflecting surface (STAR-IRS), has been proposed in this work. A Harris Hawks optimizer algorithm (HHOA)-based two-stage alternating iteration algorithm (TSAIA) is presented to jointly optimize the magnitude and uniformity of the received optical power. Besides, to demonstrate the superiority of the proposed strategy, several benchmark schemes are simulated and compared. Results showed that compared to other optimization strategies, the TSAIA scheme is more capable of balancing the average value and variance of the received optical power, when the maximal ratio combining (MRC) strategy is adopted at the receiver. Moreover, as the number of the STAR-IRS elements increases, the optical power variance of the system optimized by TSAIA scheme would become smaller while the average optical power would get larger. This study will benefit the design of received optical power distribution for indoor VLC systems.