Yes, the ultraviolet light in the sun light is very harmful to the eyes. A long time of exposure to the sun can do damage to the cornea, the conjunctiva, the retina, and the crystalline lens.Your eyes get red after exposure to the sun may be caused by the harm of the ultraviolet light in the sunshine to your conjunctiva. And the harm is accumulated as well as permanent. The ultraviolet light can cause the degeneration of the the conjunctiva, which can leads to palpebral fissure. The ultraviolet light can also increase the speed of the crystalline lens muddy, which will lead to cataracts. And ultraviolet light can affect the retina and lead to the macular degeneration. Therefore, you should do good sunscreen of your eyes when you are outside in the sun. First of all, wear a pair of sunglasses of which the colors of dark brown and deep green are the best. If you are interested in the sunglasses, you can refer to the following website for further information.
Exposure eyes to the sun without the protection of sunglasses can lead to eye redness. And I am sure that your eyes are sensitive to sunlight and you must have been staying in the sun without wearing sunglasses. The UV and UVB in the sunlight are harmful to your eyes. Our eyes have the ability to defend the UV and near-UV light on their own. However, if you stay a long time in the sun or the light is too intense, your natural defenses will be overwhelmed. This will make your eyes red. Other painful sensations like dryness, burning, and wateriness may also occur. Besides, you should consult an ophthalmologist about your light sensitivity. Anyway, I suggest you to wear sunglasses whenever you are out in the sun, for repeated exposure of eyes will result in permanent vision impairment.
It is well-known that exposure skin under the sun, will make our skin red and hurt. So do our eyes. UV radiation can damage eye's surface, cornea and lens. Exposure under the sun for a short term may cause photokeratitis. It is an inflammation of the cornea caused by UV radiation. Symptoms includ tearing, pain, red eyes etc. Long term exposure is more serious. It will increase the possibilities to get cataract and may harmful to people's retina. Still, it is uncertain that UV radiation will cause how much damage, but it is important to wear good quality glasses. So when you go our door, you had better do protection.