In a mouse model of acute light-induced retinal degeneration, positive correlations between the levels of DHA, the levels of n3 PUFA lipid peroxidation, and the vulnerability to photooxidative stress were observed. On the other hand, higher sensitivity of the electroretinogram a-wave response, a measure of the amplification of the phototransduction cascade, was correlated with higher retinal DHA levels. These results highlight the dual roles of DHA in cellular physiology and pathology.