Ophthalmologist's Advice: Wear Sunglasses When Going Out in Summer

When it comes to summer sun protection, many people focus solely on their skin, often overlooking their eyes, an organ prone to aging.

Wearing sunglasses outdoors not only blocks dazzling sunlight but, more importantly, this habit helps prevent various eye diseases.

Potential Harm of UV Light to the Eyes

The cornea, located on the outermost layer of the eye's surface, is sensitive to ultraviolet (UV) light and protects the internal eye tissues.

However, prolonged UV exposure can lead to corneal lesions, such as solar keratitis, and in severe cases, corneal opacity, resulting in vision loss.

Additionally, UV light can easily cause the following damage to the eyes:

Cataracts: Primarily refers to senile cataracts, the leading cause of blindness in the elderly.

UV radiation is one of the important causes of cataract formation, especially cortical cataracts, which are closely related to UVB (ultraviolet rays with wavelengths of 280-320 nanometers, medium wave).

Studies have found that areas with strong sunlight not only have more cataract patients but also an earlier age of onset.

The high incidence in tropical and plateau regions is because the lens can absorb almost all UV light with wavelengths between 295 and 400 nanometers.

Macular Degeneration: Primarily refers to age-related macular degeneration, the leading cause of irreversible vision loss in people over 60.

Chronic light damage to the macula, including UV and visible light, is one of the causes.

An American study found that people who spent more than 5 hours in the sun daily in summer had twice the probability of developing macular degeneration compared to those who spent less than 2 hours.

Pterygium: This is a fibrovascular tissue connected to the conjunctiva that grows onto the cornea.

It not only affects appearance but can also cause corneal astigmatism, leading to vision loss, and is related to wind, sand, dust, and sun irritation. Excessive UV exposure, along with wind and dust irritation, leads to non-infectious inflammation around the corneal limbus, causing cell and blood vessel proliferation that forms a fibrovascular membrane.

Snow Blindness: This eye condition is mainly an eye injury caused by light reflection from electric welding, plateaus, snowy areas, and water surfaces.

UV light causes acute damage to the cornea and conjunctiva through photochemical action, leading to protein coagulation and denaturation, and necrosis and shedding of corneal epithelium.

Among them, UV light with a wavelength of 280 nanometers causes the most damage to the cornea.

Choosing the Right Lens Color for Different Scenarios

When selecting sunglasses, people often prioritize aesthetics.

In fact, choosing the correct lens color is a prerequisite for eye protection. Different scenarios have different recommendations:

Grey: Moderate in depth and reduces glare, without altering the true color of objects, making the field of vision clearer and visual experience more comfortable.

It is suitable for all weather conditions and environments. 

However, the darker the grey tint, the more light it blocks. It is important to note that when driving, do not choose lenses that are too dark, such as black, as this may cause visual delay due to alternating light and dark stimuli, affecting traffic safety.

Brown: Brown-tinted lenses can absorb almost 100% of UV, infrared, and most blue light. They are very suitable for outdoor activities like hiking, playing golf, or driving. They not only help enhance color contrast, making objects clearer, but also have a soft and comfortable hue that can relieve visual fatigue. The American Academy of Ophthalmology states that brown-tinted sunglasses are also the best choice for water sports.

]Furthermore, wearing brown sunglasses is also suitable for middle-aged and elderly people with poor vision.

Green: Green lenses offer good contrast, balance colors, and filter some blue light, reducing visual fatigue.

Yellow/Orange: Although it may be cloudy sometimes, UV radiation can still be strong. Yellow or orange sunglasses allow more light to pass through the lens, enhancing light contrast.

Additionally, these can be worn when driving in low-light conditions like dusk or heavy fog to increase visual clarity.

Red: Red or rose-colored sunglasses can significantly alter colors while enhancing contrast, making them suitable for environments with strong light such as skiing. However, due to potential color distortion, they are not recommended for design professionals.

Precautions When Wearing Sunglasses

SUNMIRR reminds that sunglasses should not be chosen haphazardly, as they may not provide protective effects otherwise.

Here are some specific recommendations:

Choose Professional Optical Stores: Ensure quality by choosing reputable vendors and selecting sunglasses at professional optical stores.

If you have any eye conditions or vision problems, you should consult an ophthalmologist.

Lens Selection for Nearsighted Individuals: For nearsighted individuals choosing prescription sunglasses, the lens material should primarily be resin.

The color is also important: lenses that are too light offer little filtering, while those that are too dark can affect vision.

It's best to choose grey or brown lenses and check for dizziness or high transparency when trying them on.

In terms of sun protection, UV400 sunglasses provide 100% UV protection and are therefore the best choice.

Sunglass Lifespan: The shelf life of sunglasses is two years. Prolonged exposure to sunlight can reduce their UV protection capabilities.

Not replacing them regularly can lead to corneal damage and vision problems. A 2023 study by an academic team at the University of São Paulo, Brazil, found that if sunglasses are worn for 2 hours daily, their UV protection function significantly declines after two years and they must be replaced.

Wear Sunglasses Even with Hats or Umbrellas: Even when using a parasol or wearing a sun hat, sunglasses should still be worn.

This is because hats and umbrellas can only block UV rays from certain directions but cannot block UV rays reflected from the ground.

SUNMIRR kindly reminds that sunglasses are not suitable for everyone. Individuals with glaucoma, ocular developmental disorders (such as microphthalmia, narrow palpebral fissures, small anterior chamber angles), those predisposed to glaucoma, colorblindness, night blindness, optic neuritis, central serous chorioretinopathy, and preschool children whose visual function is still developing, should not wear sunglasses.