The sun's ultraviolet rays can cause anything from cataracts to cancer on the eyelid.

"Many people walk around with little keratosis, or sort of lesions on their skin and don't think much of them. Around the eyelid they can actually cause ulceration and erosion and those are the ones that can be most malignant," said Dr. Rishi Singh, an ophthalmologist with Cleveland Clinic.

The sun gives off two types of ultraviolet rays: UVA and UVB. Ultraviolet-A radiation can penetrate deep into the eye and damage the cornea or retina.

Excessive sun exposure may also accelerate the aging process of the eye.  You also increase your risk for things like cataracts and macular degeneration, which is the leading cause of vision loss for older adults in the United States.

"There may be limitations or issues with people being out in the sun for long periods, not wearing sunglasses, and causing oxidative stress and damage- leading to macular degeneration," said Dr. Singh.

UVB rays are absorbed by the cornea and the lens. UVB rays can cause things like a corneal sunburn, which is painful and may cause temporary vision loss.

"The cornea is one of those exposed mucus membranes. It's a very moist organ and it needs to be continually lubricated. So, having it exposed to sun elements and dry it out completely only leads to a significant decrease in vision," said Dr. Singh.