As summer approaches, more time will be spent outdoors enjoying the longer days, warmer weather, and, especially, lots of sunshine! While time outdoors is a great way to get active and can be a benefit to health, protecting your eyes from the UV light of the sun should always be a concern.
How is Sunlight Different than Other Lights?
When discussing the need for sun protection, a common question is how does the light emitted by the sun differ from other lights like those inside.
This difference is based on the physical properties of the two lights. The wavelength of light determines the amount of energy the light contains with shorter wavelengths having considerably more energy than longer wavelengths.
A typical light bulb will only emit light with wavelengths in the visible light spectrum (400-650 nm). These wavelengths combine to form a white light that is perceived by our eyes.
Even a light emitting only visible light can produce energy in the form of heat – think of the concept of Easy Bake Ovens – but this energy is very low and does not travel far from the light source.
On the other hand, the sun emits light in a broad spectrum well beyond the visible light range. This includes ultraviolet (UV) light which has shorter wavelengths than visible light.
The shorter wavelength UV light has much higher energy than visible light and thus can cause damage very far from the light source.
How UV Light Causes Damage
UV light affects the body at a cellular level by altering DNA and damaging proteins. The tissue that absorbs the UV light can become damaged and potentially even destroyed from the UV radiation.
The skin is the primary absorber of UV light throughout the body, however in the eye, the cornea and lens also absorb UV light.
Affects of UV Light from the Sun
If the body is exposed to intense UV light for a long period of time, the skin will become red and feel warm to the touch – a sunburn.
Similar changes can occur in the eyes but require much longer duration or higher intensity light.
Over time, changes such as cataracts, pterygiums, corneal inflammation, and even cancerous lesions can occur in or around the eyes.
Protecting Your Eyes from the Sun
To protect your eyes from the harmful affects of UV light, you can wear UV blocking sunglasses, UV blocking contact lenses, wear a hat with a brim, or apply sunscreen to the eyelids.
The most common sun protection is sunglasses. While any sunglasses will provide some protection by covering the skin around the eyes and filtering some of the light, sunglasses with specific UV blocking properties are the best option for protecting your eyes.
Similarly, many contact lenses are made with inherent UV blocking properties which prevent the UV light from damaging the internal portions of the eyes.
An alternative is wearing a hat with a brim that will shield the eyes and area around the eyes from direct sun exposure. This is a great option to combine with sunglasses for the most protection possible.
While sunscreen should never be applied inside the eye or to the surface of the front of the eye, applying sunscreen to the eyelids can prevent a harmful sunburn in the area. The eyelid skin is the thinnest in the body and may burn quicker than other areas.
No matter the method, it is important to consider UV protection and plan at least one method of protection for you eyes before spending a day, or even a few hours, in the sun.
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