Electroretinoraphic signals (ERGs) are affected when recorded under isoflurane anesthesia in the operating room. We explored the effect of isoflurane and propofol in ex vivo guinea pig retinal preparations using a multielectrode array to record simultaneously ERGs and retinal ganglion cell (RGC) activity. The viability and light-response characteristics of the model were documented. In the presence of isoflurane, the ERG and RGC activity was reduced in a dose-dependent manner, even at sub-clinical doses; the OFF responses were consistently more affected. Propofol had minimal effects: at subclinical doses, a small excitation was measured while a concentration a hundred times stronger than the clinical concentration was required to measure a significant decline in EGR and RGC signals. This study confirms the usefulness of the guinea pig model to study clinically relevant retinal issues and shows that propofol is a better anesthetic to use in the operating room when retinal investigations are required.