Cataract continues to be a leading cause of low vision and blindness worldwide, despite the fact that cataract surgery routinely restores vision immediately for many cataract patients. Accordingly, defining risk factor-specific mechanisms of cataract formation, and associated protective responses within the lens, holds promise for identifying drugs that can delay cataract formation or progression. As heat is a known cataract risk factor, we hypothesised that exposing human lens tissue to increased temperature would initiate protective responses. To begin defining the initial responses of human lens tissue to increased temperature, we used human pluripotent stem cell-derived, ROR1-expressing (ROR1e) human lens epithelial cells and micro-lenses. Our results show that exposing human micro-lenses to 39°C for 15 minutes did not affect transparency or focusing ability. In contrast, exposing micro-lenses to 46°C or 55°C for 15-minutes significantly decreased both micro-lens light focusing and transparency. Mass spectrometry analyses of ROR1e cells and micro-lenses exposed to 39°C identified 2 proteins – HSPA1A and HSPA1L – that were quickly and significantly upregulated in ROR1e lens epithelial cells in response to the heat treatment. These results provide new information on lens protection mechanisms that may be relevant to future attempts at delaying cataract formation.