Anything got in the eyes will cause discomfort. When you get some water, hairspray or even something edible in your eyes, your eyes will have stinging or burning sensation. The case with sperm is the same. The sulfuric acid from the combination of uric acid in sperm and eye moisture will make your eyes stinging. However, it is easy to handle with. You can rinse the inside of your eyes with clean water (tap water is ok). Then you can drop artificial tears to your eyes to flush the remaining sperm out. By doing this, you will be fine. If not, it is possible that you are allergic to sperm. But this case is very rare. If you are really allergic to sperm and your eyes cannot recover after the cleansing, you should turn to your doctor as soon as possible.
If you don't get clear of the sperm in the eyes, it will be bad for your eyes because it may become solid after some time. At the same time, it will stimulate your eyes because of the irritations. You should better wash the sperm out of the eyes with clean water. That is very important for you. Then you could use the clean cloth to dry it.
Generally speaking, the sperm cannot do much harm to your eyes. The sperm consists of ninety-nine percent of fluids and one percent of tangible matters, such as proteins, sugar, glucose, fructose and so on, which is not irritative enough to do harm to the eyes. If you get sperm in your eyes by accident, you can just use clean flowing water to wash your eyes, and then apply aome antibiotic eye drops to the eyes in case of getting infected by bacteria and leading to conjunctivitis.