UV radiation can cause "sunburned eyes" and permanent vision loss

Summer has arrived, bringing plenty of sunshine and outdoor activities. Many people habitually apply sunscreen, but high-intensity UV rays not only damage skin but can also cause irreversible harm to eyes. Experts point out that UV radiation can lead to "sunburned eyes," triggering issues ranging from acute pain to permanent vision loss. Just as we protect our skin with sunscreen, protecting our eyes is equally important.

Sunburned Eyes: Photokeratitis

According to foreign media reports, Dr. Paramdeep Bilkhu, Clinical Adviser at the College of Optometrists (UK), explains that the eyes are very delicate structures, and UV exposure can cause multiple problems. Bilkhu explains that with short-term exposure to high levels of UV radiation, the eyes can actually get "sunburned" – a condition called photokeratitis. Typical symptoms include:

• Acute redness and swelling of the eyes
• Excessive tearing
• Photophobia (extreme sensitivity to light)
• Blurred vision
• A sensation of having a foreign body or "grittiness" in the eyes

It's important to note that this condition doesn't only occur on sunny days. Risk is higher at high altitudes (especially when skiing) because sunlight not only comes from above but also reflects intensely off snow, ice, or water surfaces. Even on cloudy days, UV index can still be high and cause damage.

Cataracts, Macular Degeneration, and Skin Cancer Around the Eyes

Whether indoors or outdoors, hot environments accelerate the evaporation of the tear film on the eye's surface. Bilkhu says this is why people experience dry eyes more easily in warm climates. Long-term exposure to high UV environments can lead to the following eye conditions:

• Cataracts: Long-term, high-dose UV exposure is clearly linked to cataract formation. People who spend long periods outdoors frequently with high annual exposure tend to develop more severe cataracts at a younger age.
• Macular Degeneration: Cumulative annual UV exposure is also associated with the development and severity of macular degeneration. If left untreated, it can lead to permanent vision loss.
• Skin Cancer Around the Eyes: The skin surrounding the eyes is very fragile. Long-term exposure to high UV environments increases the risk of basal cell carcinoma, the most common type of skin cancer around the eyes. Although this type of tumor grows relatively slowly, it can still cause severe damage to ocular structures.

5 Tips for Eye Protection from UV Rays

Bilkhu offers the following practical advice to help people protect their eye health while enjoying the sunshine:

1. Check the UV Index: Most weather websites or mobile apps provide the UV Index (UVI). When the index exceeds 3, you should not only protect your skin with sunscreen but also wear good quality sunglasses to protect your eyes.
2. Choose Certified Sunglasses: Many mistakenly believe that darker lenses offer stronger protection – this is a myth. Look for a CE mark or UKCA mark, which indicates the sunglasses meet European standards and effectively block harmful UV radiation.
3. Consider Wraparound Sunglasses: Wraparound designs block UV rays from the sides, offering more comprehensive protection, especially for those spending long hours outdoors.
4. Wear a Wide-Brimmed Hat: A wide-brimmed hat provides extra protection, particularly for those whose scalps or faces burn easily. The hat reduces both direct and reflected UV rays entering the eyes.
5. Get Regular Eye Exams: Even without any symptoms, schedule a comprehensive eye exam with an optometrist every two years. This is the best way to detect eye problems early (and can even reveal other systemic health issues).

Consumer Council: How to Check Sunglasses Labels

The Hong Kong Consumer Council reminds consumers to check the label on sunglasses for information on their UV protection capabilities. The following labels indicate the lenses block all UV radiation:

• "100% UV Protection"
• "Total UV Protection"
• "UV 400"

The most common type available are sunglasses claimed to meet European/International Standard ISO 12312-1. Some sunglasses may also claim to meet US standard ANSI Z80.3 or Australia/New Zealand standard AS/NZS 1067.

According to International Standard ISO 12312-1, lenses are divided into 5 categories (0 to 4), each with different requirements for light transmission and UV penetration, making them suitable for different uses:

• Categories 0 to 1: Decorative use, limited ability to block intense sunlight.
• Categories 2 to 3: General use, good ability to block intense sunlight.
• Category 4: Special use, complete blocking of intense sunlight.

Note: Category 4 sunglasses, for special use, have light transmission not exceeding 8%. They significantly reduce overall brightness, making it difficult for drivers to distinguish traffic signal colors. Therefore, they are unsuitable for driving.

Sources: Irish News, Consumer Council (Hong Kong)

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