The Effects of Ultraviolet (UV) Radiation on the Eyes

What words come to mind when you think of a bright and sunny holiday destination such as California? Beach, white sand, water? Surfing, sun, sunburn, awkwardly-located tan lines? How about Pterygium?

Pterygia, or its singular form, pterygium, is a benign overgrowth of conjunctival tissue on the eye and has a worldwide prevalence of about 10.2%1. The first part of the word, ptery, is derived from the Greek meaning “wing” (think of the winged pterodactyl), as the typical shape of a pterygium is a triangle. The conjunctiva is a membrane that sits over the whites of the eye, and if it grows over the cornea, the clear bubble over the coloured part of the eye, we get what we call a pterygium. Its little cousin, a pingueculum, is also an overgrowth of conjunctival tissue that presents as a little white or off-white yellowish bump on the sclera but doesn’t encroach onto the cornea.

Ultraviolet Radiation is a Strong Contributing Factor to Pterygium
Macular degeneration, cataracts, skin cancer, and photokeratitis are eye diseases and conditions that are caused by exposure to ultraviolet (UV) radiation.

The formation of pterygia is also caused by exposure to ultraviolet radiation2, hence the word association with sunny beachside California and why it’s also referred to as Surfer’s Eye. Other risk factors for the presence of pterygia include darker skin color, increasing age, and greater amounts of outdoor activity3,4. Studies have also shown that men have more than twice the risk of developing pterygia than women3,4, which possibly relates to men in general typically spending more time in activities that involve UV exposure, such as outdoor work, welding, or surfing on the highly reflective waters of the North Pacific Ocean. For example, a research study into a population of Latinos living in Arizona, USA found a high prevalence of pterygia at 16%; this study also found links between lower income and educational status with higher rates of pterygia5.

How to Manage and Treat Pterygium
In most cases, it’s okay to simply monitor a pterygium without surgical intervention. Some patients may not like the appearance of the pterygium and quite often it will be the cosmetic factor that drives them to seek surgical removal. Other indications to have the pterygium addressed will be if it has grown so far over the cornea that it starts affecting vision, usually by causing astigmatism1, which is a type of refractive error. Sometimes a pterygium may also become inflamed and red, which can be both uncomfortable and unsightly, especially if trying to impress the surrounding bikini-clad beachgoers (“Eww, no I will not grab a margarita with you, you have pink eye!”).

Management of an early pterygium will involve UV protection in the form of sunglasses or a hat, and lubricant or anti-inflammatory eye drops can be used if it gets irritated. In cases where the pterygium has grown to the point that cosmesis and/or clear vision become an issue, surgical removal by an ophthalmologist is recommended. This involves excision of the offending tissue with a bladed instrument as a day procedure, and typically you will be sent home with an eye shield and some medicated drops to hasten the healing process. The most common complication after surgical removal is recurrence of the pterygium but modern techniques have reduced this rate from a previous whopping 97% within the 12 month post-operative period down to 5-10%1.

 

Although Pterygium removal advancements have reduced recurrence rates to 5-10%,
Dr. Michel still considers that rate to be too high.
He experiences a Pterygium removal recurrence rate of less than 1% with his elegant no-stitch technique.

 

The reason for this improvement in the rate of recurrence is the use of a tissue graft to cover the removal site on the eye as opposed to leaving it bare and naked – such a state is evidently not appropriate for a public beach or for a pterygium removal. The tissue used to cover the surgery site is either a human amniotic membrane, which is the innermost layer of the placenta, or a conjunctival autograft, which is just a fancy term for taking a bit of your own healthy conjunctival tissue from one place on the eyeball and placing it somewhere else.

Pterygium Is Benign and Non-Cancerous But Is Still a Sign of Ultraviolet Damage To The Eye
While a true pterygium or pingueculum is benign and non-cancerous, it is still a sign of ultraviolet damage to the eye. UV exposure is also related to other ocular conditions, which include cancers of the eye that can sometimes mimic the appearance of a pterygium or pingueculum. It is always a good idea to seek an optometrist’s or ophthalmologist’s assessment on any new growth, lump or bump on the eye. Ignoring a growing bump on any part of the eye could result in a cancerous lesion going unchecked and the possibility of the eye being removed altogether if it is discovered too late.

Remember that good UV protection goes a long way. Sunglasses and a hat or lazing under the shade of a palm tree not only makes for a great photo for Instagram, it’ll also prevent pterygia from winging their way over your eye.

 

References

  1. Pterygium – Latin America. American Academy of Ophthalmology. https://www.aao.org/topic-detail/pterygium-latin-america
  2. Moran DJ, Hollows FC. Pterygium and ultraviolet radiation: a positive correlation. British Journal of Ophthalmology 1984;68:343-346. https://www.ncbi.nlm.nih.gov/pubmed/6712914
  3. J Panchapakesan, F Hourihan, P Mitchell. Prevalence of pterygium and pinguecula: The Blue Mountains Eye Study. Clinical & Experimental Ophthalmology. May 1998;26:2-5 http://onlinelibrary.wiley.com/doi/10.1111/j.1442-9071.1998.tb01362.x/epdf?r3_referer=wol&tracking_action=preview_click&show_checkout=1&purchase_referrer=onlinelibrary.wiley.com&purchase_site_license=LICENSE_DENIED
  4. Liu L, Wu J, Geng J, et al. Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis. BMJ Open 2013;3:e003787. doi: 10.1136/bmjopen-2013-003787. http://bmjopen.bmj.com/content/3/11/e003787
  5. Prevalence of pterygium in Latinos. https://www.ncbi.nlm.nih.gov/pubmed/19570772

 

 


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