You may get irritation when you take a shower. As we know, the shower water is not the same PH as your eyes. If there is a water into your eyes when you take a shower, it is likely cause an irritation that gradually subsides as the eye fluids flush out the water residue. If you want to reduce your red eyes immediately, you may flush your eyes with saline solution or OTC eye drops.
Perhaps you have mistaken or been oversensitive to such phenomenon. Try to reexamine your eyes while taking another shower. It is likely that you have overused your eyes. If this doesn't work, try to visit a doctor and see what had happened to your eyes. You may also wear goggles when taking a shower.
You have red eyes after shower maybe because your eyes are irritated by the shower water or chemicals in your shower products. Sometimes my eyes also burn and turn red after shower if the water get into my eyes while showering. Flushing your eyes with clean and cool water will help relieve it.
The red eyes mainly are caused by three reasons- infection, irritation and allergy. So personally I think that you red my are probably caused by infection or irritation. Your eyes are infection by the bacterial of your bathing water or irritated by the hot temperature of the water. However, no matter which is the cause, you can use the cold compress and artificial eye drops to make you feel better. Hope this helpful.