How to protect your eyes from the sun?

The sun is not safe for eyesight. In good weather, how can you limit the risks to your eyes? We answer you!

What are the dangers of the sun for the eyes?

UV rays:A, B and C

Ultraviolet rays are of three kinds, depending on their wavelength:

• UV A rays:the most dangerous. They can damage the lens in adults and even the retina and cornea in children,
• UV B and UV C rays:considered less aggressive, they are not harmless and are absorbed by the lens and the retina.

The amount of UV rays to which we are exposed is independent of the heat felt (on a cloudy day, for example).

It can be greatly increased by the phenomenon of light reflection on light surfaces (e.g. white walls) or reflective surfaces (e.g. glass buildings):

• water reflects up to 10% of UV,
• sand up to 20%,
• 85% snow.

The effects of UV rays on the eyes

UV A, B or C, all UV rays are dangerous for the eyes.

UV rays can cause dangerous injuries for those who expose themselves without protecting their eyes, and they can also promote the appearance of certain eye pathologies:

• ophthalmia: it affects the cornea and is caused by the reflection of UV rays from snow, sea and sand. It can also be due to exposure to a UV lamp without protection. Ophthalmia can be compared to a strong sunburn, resulting in a burn of the surface layer of the cornea:the corneal epithelium.

Ophthalmia is manifested by:

• • • tingling, a feeling of "sand under the eyelids" which can range from simple discomfort to pain at the limit of tolerance,
    • pain with eye redness, tearing and photophobia (difficulty tolerating light sources).

These inconveniences appear between 2 to 8 hours after exposure. The treatment is based on the occlusion of the eyes with a bandage. An analgesic may be prescribed to relieve the pain. Most often, the situation returns to normal in less than 48 hours and without leaving any sequelae.

• early onset cataract :it is a clouding of the lens, the small oval lens located behind the pupil. The vision then becomes blurred, with duller colors,
• acceleration of AMD (Age-Related Macular Degeneration):It affects the central part of the retina. AMD can lead to loss of central vision, requiring the patient to undergo low vision rehabilitation,
• severe retinal damage,
• skin cancer on the eyelids,
• inflammation of the ocular mucous membranes,
• Corneal ulceration (keratitis),
• spring keratoconjunctivitis: it mainly affects young boys (before puberty). This pathology is typical of Mediterranean regions, and becomes more virulent in summer. Affected subjects show hypersensitivity to light and heat, affecting the conjunctiva. Keratoconjunctivitis lasts about 10 years and then resolves spontaneously. Sequelae sometimes remain, such as a decrease in visual acuity,
• Solar Retinopathy: it is an inflammation of the retina, causing macular edema. Excess light, affecting the retina, causes sometimes painful glare. This lesion mainly affects people who have spent too much time staring at the sun, especially during eclipses. The center of the retina can be burned due to this exposure. A black spot appears in the forward visual field, color vision is impaired, and straight lines appear curved. Macular edema is in principle regressive:in a few days, or a few months, vision returns to normal, thanks to a cortisone-based treatment, applied locally. But when the macular edema is too severe, the person affected can suffer sequelae, such as a reduction in their visual abilities.

When and where is the eye exposed to the sun?

In Metropolitan France, it is prudent to be vigilant from the beginning of May until the end of August:the sun's rays are very virulent during this period, especially between 12 p.m. and 4 p.m.

Exposure of the eyes to UV is done by:

• direct exposure:rays directly received by the eyes,
• scattering:the rays present in the atmosphere,
• reflection:Rays reflected from certain surfaces.

The aggressiveness of the sun's UV rays can manifest itself without any feeling of heat:in overcast or windy weather, for example.

In particular, their intensity is enhanced by reverberation on light surfaces (snow, sand or water) and when at altitude:+ 10% every 1000 meters.

It is therefore necessary to be particularly vigilant during stays at the sea or in the mountains.

Who are the most sensitive people to the sun?

• the babies and children are very vulnerable:their eyes are much less equipped to resist UV rays than those of adults,
• the elderly already suffering from cataracts or macular degeneration (AMD):their pathologies can be aggravated by insufficient or unprotected sun exposure,
• protection is also recommended for people with fair skin, eyes and hair. Also affected are people with many moles, as well as family members at risk of developing skin cancer.

How to protect your eyes from the sun?

Protecting your eyes from the sun:practical tips

• avoid exposure between noon and 4 p.m.
• if you are outside in this time slot, look for shady places,
• systematically protect children:their eyes are very fragile and more sensitive than those of adults to the effects of UV rays,
• wearing a hat or cap is recommended.

Choose your sunglasses wisely

To be effective, sunglasses must:

• bear the CE marking:proof that they meet European safety standards,
• block UV rays:lenses must be treated with UV protection,
• protect against sunlight and glare:the degree of protection is indicated by a specific index between 0 and 4, from the lowest to the highest. It is represented by a pictogram,
• respect the colors as much as possible, especially if they are used for driving,
• be impact resistant,
• have good optical qualities,
• for children:prefer plastic materials, which are more resistant than glass, and choose a model that covers the eye well to protect it as much as possible.

Note:

• Dark lenses only protect if they are UV treated. Otherwise, they aggravate the damage by promoting pupil dilation and increasing the amount of harmful rays received by the eyes. Clear anti-UV treated lenses are effective, not heavily tinted lenses if they are not anti-UV treated,
• contact lenses often benefit from UV treatment and they protect the part of the eye they cover:cornea, lens, retina. For optimal protection, you should also wear sunglasses,
• additional lens treatments improve visual comfort:for example, polarizing lenses eliminate glare from reflective surfaces.

Protection ratings:what to choose?

• Category 0:weak protection

Lenses filter less than 20% of UV rays. They are clear or very slightly tinted.
These are comfort glasses, for aesthetic purposes, which do not provide effective protection against UV rays. It is possible to use them indoors, or in places with little exposure to the sun in the city and in the countryside.

• Category 1 :low protection

Lenses filter 20-57% of UV rays. They are slightly tinted.
Their low protection limits their use to weak sunlight, for example in overcast weather and in winter.

• Category 2: average protection

The lenses filter out 58-82% of UV rays. They are moderately tinted. Intended for the city and the countryside, they provide average protection against UV rays. They are suitable for average sunlight, for less sensitive eyes.

• Category 3:high protection

The lenses filter between 83 and 92% of UV rays. They are dark. Their level of UV protection is good. They are suitable for strong sunlight, at sea, in the mountains and for driving.

• Category 4:very high protection

The lenses filter out over 92% of UV rays. They are very dark.
They are suitable for very high levels of sunshine. They are prohibited for driving, as they reduce the visibility necessary for the driver.
On the other hand, they are suitable for the sea and in the mountains and of an ideal quality in the event of reverberation (sea, snow, sand).

Does lens color matter?

• The grey lenses, high mountain equipment, ensure good perception of natural colours,
• brown lenses provide good protection against glare and enhance contrasts,
• yellow glasses enhance contrast at night and in foggy weather:they are suitable for driving in gray weather,
• the blue lenses are not very protective, and are only suitable for low light.

There are glasses for each activity

There are models adapted to the activities practiced:high mountains, car driving, city, running, cycling, swimming and nautical activities, hang-gliding...

Shapes, colors, materials used, there is something for everyone. The important thing is to choose a good level of UV protection.

References

Sources

• National Institute for Prevention and Health Education (INPES). Make the most of the sun's rays:prevention tips to protect yourself from the sun.
• National Association for the Improvement of Sight (ASNAV). Protect yourself from UV

Writing

• The Prevention Offer Team of the Mutualité Française
• Dr Claire Allais, general practitioner.