AIM: To analyse the effect of trypan blue on the retina in an experimental setting of macular surgery. METHODS: Porcine eyes were used within 3 hours after death. The eyes were hemisected and the vitreous removed. Trypan blue (0.15%) was applied over the trephined posterior pole, whereas the rest of the eye cup was filled with a balanced salt solution (BSS). The dye and the BSS were removed after 1 minute and the complete eye cup irrigated and filled with fresh BSS. Both the treated and untreated retinas were illuminated with a standard surgical light pipe and source at maximum power for 10 minutes. Both the trypan blue exposed retina and the non-treated surrounding retina were processed for histology. RESULTS: Exposure of the retina to trypan blue for 1 minute, followed by illumination caused no histologically detectable damage compared to the controls. No microarchitectural disorganisation, cellular disruption, or affection of the vitreoretinal interface was detected. CONCLUSIONS: These findings indicate that a 1 minute exposure of trypan blue followed by illumination does not cause an acute morphologically detectable toxic effect on the porcine retina.