The Sun, UV Light and Eye Health

Exposure to the sun can be good for you in many ways. Exposure to natural Ultraviolet radiation (UV light) can be good for your skin and mental health, and it appears to even help regulate sleep cycles. Sleeping is important for your eyes. While you sleep, your eyes are constantly lubricated so they can clean away the detritus of the day - dust particles, smoke, pollen and the like - keeping your eyes in prime condition for the day ahead. 

Research suggests there is a link between sleep cycles and exposure to natural light, especially in older people, an age group in which insomnia is more common and the eyes generally have more trouble processing blue light., the kind of light believed to have an affect on biorhythms. 

You can have too much of a good thing. Exposure to too much UV can be as bad as limited exposure can be good. Sunburn and skin cancer are two well known results of UV light exposure, but the effects it can have on the eyes are just as detrimental, in both the short and long term.

Short Term Sun Exposure Problems

Short term exposure to UV can lead to a number of temporary complications or can aggravate existing conditions. Depending on the level of exposure, these short term problems can range from mildly irritating to quite debilitating.

  • Corneal sunburn - Your skin isn’t the only thing that can get sunburned. Also known as Ultraviolet Keratitis or a corneal flash burn, sunburn of the corneas causes the usually clear layer of cells that covers the cornea (in front of the coloured part of the eye) to become damaged, leading to pain, a dry, scratchy or itchy sensation of one or both eyes, eye wateriness, excess blinking, light sensitivity, a change in vision or even loss of vision. In addition to UV from sunlight, many other sources of UV, including welders, halogen lamps, sun lamps, and even lightning strikes can cause corneal flash burn. 
  • Snow Blindness - A specific type of corneal flash burn associated with the snow. You don’t have to look directly at the sun for damage to occur. Snow can reflect around 80% of the sun’s UV radiation and as you’re more likely to be looking down than up, this reflected light is a problem for skiers and those in snowy climates. A few hours exposure to reflected UV without eye protection can lead to painful temporary blindness.

Long Term Sun Exposure Problems

Continued exposure of the eyes to UV light over time can have long term detrimental effects and lead to a number of chronic eye diseases, including:

  • Pterygium - Commonly known as “surfer’s eye” pterygium are wedge shaped lumps that grow in the conjunctiva or mucous membrane of the white part of the eye and sometimes invade the cornea. While UV light is the main cause of development of pterygium, wind and dust also appear to play a part. These growths typically appear in people from 30-50 years old and can lead to a range of symptoms. Some pterygium causes no pain or discomfort, but others can cause itchiness, a burning sensation, blurred vision, the feeling of a foreigh body in the eye and more. Pterygium that covers the cornea can lead to corneal scarring and a change of vision.  
  • Actinic Keratopathy - Also known as Labrador or Droplet Keratopathy, this chronic eye disease is a form of corneal degeneration characterised by deposits (or droplets) of yellow ot white material (fats and cholesterol) in and around the pupil the cornea. These deposits can be raised lumps, sometimes in a ring formation, and can lead to significant changes in vision.
  • Cataracts - The clouding of the lens of the eye or its surrounding fluid, cataracts are one of the major causes of vision impairment in Australia. Though they typically appear more frequently in older demographics, cataracts can appear at any age, especially in those who have had prolonged exposure to UV light without adequate eye protection. Cataracts typically gradually increase in severity, therefore they can decrease your vision significantly without you really being aware. Cataracts can cause a number of symptoms including blurred or double vision, sensitivity to glare and muted vision, as if looking through a filter or haze. 
  • Eyelid Skin Cancers - The eye is housed in a thick bone structure known as the orbit, protecting it from a lot of harm, but the tissue that covers the eye, the upper and lower eyelid are quite fragile and can easily be damaged by the sun. The most common form of eyelid cancer is a basal cell carcinoma, and while these cancers don't often spread to the lymph nodes and throughout the body, they can grow large enough to cause significant discomfort and disfigurement. Rarer forms of cancer, such as squamous cell carcinoma and melanoma can develop on the eyelids. These cancers have a much higher chance of spreading and causing significant damage, even death.  
  • Conjunctival Squamous Cell Carcinoma - These cancers typically appear as easily visible pink, yellow or white tumours on the surface of the eye, sometimes surrounded by large, dilated red blood vessels. Conjunctival squamous cell carcinomas are classed as locally invasive, meaning that while they rarely spread, they can and will invade and destroy the eye. Squamous cell carcinomas of the eye are more typically found in older Caucasian people than any other group.   
  • Age-Related - Age-related macular degeneration (AMD) is the leading cause of blindness in Australians, accounting for around 5% of all legal blindness in the country. Some versions of this disease can be treated, whilst others are at present untreatable and lead to life-altering vision loss.

Protecting Your Eyes from the Sun

Sun damage to the eyes can be debilitating, even disastrous, but thankfully protecting yourself from UV exposure is easy. More protection is always better than less, so multiple forms of sun protection should be used simultaneously.

  • UV Blocking Sunglasses: Wearing sunglasses that cover the entire eye and block UVA and UVB (the more damaging form of UV light) is an excellent way to protect your eyes from sun damage. Glasses that can filter 99% of UVA and UVB (allowing only 1% through) are best, as are wraparound glasses that don’t allow light in from the sides. Some contact lenses offer UV protection but more sun protection is always better, so UV protective contacts should also be matched with UV protective sunglasses. Darker lenses may be better for people with a sensitivity to bright light but they offer no additional UV protection. Grey lenses offer the least colour distortion.
  • Wide Brimmed Hats: Wearing a wide brimmed hat shades your eyes and the delicate skin around your eyes, protecting them from damage and the premature aging effect of UV exposure. 
  • Sunscreen: When applying sunscreen, make sure that you adequately apply it to your face, including your eyelids.
  • Don’t Look at the Sun: It’s kind of obvious, but don’t look directly into the sun if you care about your eyes.   

One thing to remember, though, is ultraviolet radiation is invisible to the human eye. So whilst the term “UV Light” is technically incorrect, ultraviolet radiation most often accompanies sunlight. Hence it’s usually fair to assume that the more you expose yourself to sunlight, the more you should consider protecting yourself from ultraviolet radiation that will also be present.

Protecting yourself from UV exposure is always the best line of defence, but regular eye tests are also extremely important, as they can identify early signs of damage and help you mitigate them before the problem progresses, or simply give you the peace of mind that your eyes are healthy and your efforts are paying off.

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