Shortly after ingesting the medication, he began seeing multicolored flashes. His eyes grew sensitive to light, and everything he looked at seemed to have a red tint. He continued to experience symptoms (the flashes eventually stopped) for two days before going to the New York Eye and Ear Infirmary of Mount Sinai urgent care clinic. In the case report, Fatoumata Yanoga, MD, Ronald C. Gentile, MD, Toco Y. P. Chui, PhD, K. Bailey Freund, MD, Millie Fell, MD, FACS, Rosa Dolz-Marco, MD, PhD, and Richard B. Rosen, MD described what then happened.
Testing including adaptive optics (AO) and optimal coherence tomography (OCT) imaging technology revealed that certain photoreceptors in his retina were damaged. Photoreceptors are cells in the retina, which is in the back of your eyes. As described in PubMed Health, photoreceptors absorb and convert light into electrical signals that then subsequently travel through your optic nerve to your brain where they eventually become the images that you see.
The Mount Sinai doctors found damage to his cone photoreceptors, one of two types of photoreceptors in your retina. Cones sit in the center part of your retina and help you see fine detail and color. The other type of photoreceptors are rods, which sit along the outer part of your retina and help you see in dim and dark light. Therefore, it is not surprising that damage to the cones would result in a red tint. Unfortunately, the red tint has persisted for over a year, despite steroid treatments, suggesting that this visual disturbance may be permanent.
Even when taking sildenafil citrate at recommended doses, you may experience temporary visual symptoms such as blurry vision, sensitivity to light or color changes like a blueish tint. What does your eye have to do with a medication that is supposed to act in a place lower than your eye? The medication can lead to erections by causing blood vessels to dilate so that more blood rushes into your friend down there. But since you don’t directly sildenafil to your friend, other blood vessels and blood flow can be affected such as blood flow to your retina and optic nerve. Temporarily messing with blood flow can temporarily mess with the functioning of cells in your retina. Hence the transient visual disturbances that a number of people have experienced with such medications.