Catalyzes the NADPH-dependent reduction of glyoxylate and hydroxypyruvate (HP) into glycolate and glycerate. Mostly active in the presence of NADPH and glyoxylate. glycolate + NADP(+) = glyoxylate + H(+) + NADPH (R)-glycerate + NADP(+) = 3-hydroxypyruvate + H(+) + NADPH Inhibited by oxalate. Homodimer. Disrupted photorespiratory flux leading to a slight altered leaf concentrations of the photorespiratory intermediates hydroxypyruvate (HP), glycerate, and glycine. Belongs to the D-isomer specific 2-hydroxyacid dehydrogenase family. GyaR subfamily.