HSP90B2P and macular retinal edema: To investigate whether sublethal photocoagulation induced Hsp expression, which is important in reducing macular edema, we used qRT-PCR to examine the expression levels of HSPA1A mRNA, which encodes Hsp70 protein, in a cultured cell layer irradiated with a sublethal irradiation dose using a micropulse laser (Figure 2(d)).