How To Protect The Eyes From UV Damage All Year Round

The Eyes And UV Damage

Ultraviolet (UV) radiation is present all day, all year round, in both sunny and overcast conditions. It can harm the eyes and cause damage and premature ageing to the surrounding skin. The eyes are the only organs to let light penetrate the body and humans evolved to protect them against the sun’s harmful effects. They are recessed within the head and shielded by the brow ridge, the eyebrows and the eyelashes. The pupil constricts in bright light and the squint reflex minimizes penetration of the sun’s rays into the eye.

Sunlight contains ultraviolet, visible and infra-red radiation. It is the bright visible light that activates these protective mechanisms, so on a cloudy day these protective, natural defences might not be very effective. However, UV levels can still be high, so it is vitally important to protect the eyes from UV damage all year round, rain or shine.

There is a well-known link between excessive sun exposure and skin damage. Perhaps less known is how sunlight, more specifically, UV radiation can damage the eyes. There are three categories of UV radiation: UVA (320-400nm), UVB (290-320nm) and UVC (100-290nm). The earth’s ozone layer absorbs almost all incident UVC, so the rest of this article refers to UVA and UVB.

Sunburn: Photokeratitis and Photoconjunctivitis.

Keratitis describes an inflammation of the cornea, (the clear dome-shaped lens that covers the iris and pupil). Conjunctivitis refers to an inflammation of the conjunctiva, (the clear membrane that covers the front of the eye and that lines the inside of the eyelids). Photokeratitis and photoconjunctivitis are inflammatory reactions caused by light, just like sunburn. Snow-blindness is an extreme version of this. The signs and symptoms of a sunburned eye include grittiness, redness, photophobia, excessive watering and blurred vision. Although these painful conditions usually resolve within two days, it is infinitely better to prevent this and to protect the eyes from UV damage.

Pterygium

A pterygium is a common, fleshy, benign growth on the cornea, linked to prolonged UV exposure. It is therefore, more likely to affect those that live in a hot climate or that work outdoors (in any climate). Pterygia tend to become inflamed and they can extend over the centre of the cornea, ultimately interfering with vision.

Cataracts

According to the World Health Organisation, (WHO), cataract is the most common cause of blindness in the world. It is the progressive clouding of the crystalline lens within the eye. Usually, it is a normal part of the ageing process of the eyes. However, evidence suggests that between 10 and 20% are caused by overexposure to UVB, therefore, they are preventable. (NB other causes of cataract include congenital, traumatic and genetic. These are not attributable to UV exposure and are not preventable)

Macular Degeneration

Age-related macular degeneration, (AMD), is caused by damage to the retina over time. The retina is the light-sensitive part of the eye where images are formed and transmitted to the brain. The macula is the central and most sensitive part of the retina. It is responsible for seeing in detail and in colour. The main risk factor of AMD is age. Although further research is necessary,  some studies point towards UVA and HEV, (high-energy visible or blue-violet light) as potential causes. Other possible risk factors include smoking and genetic tendendancy.

Eyelid Cancers

Cancers of the eyelid account for 5-10% of all skin cancers. Most occur on the lower lid which gets the most exposure. Basal Cell Carcinoma (BCC) is the most common of these. BCC is slow-growing and rarely spreads to other parts of the body, but it is locally invasive. Consequently, it can cause major disfigurement to the eye and face. Squamous Cell Carcinoma (SCC) has a faster growth rate and a greater potential to spread to other parts of the body than BCC. Cumulative exposure to UV is a known risk factor in both of these types of cancer.

Malignant Melanoma is a type of cancer that develops in the cells that produce melanin — the pigment that gives the skin its colour. There is a high correlation between melanomas and a history of intense, intermittent sun exposure and sunburn.

Early warning signs include:

• Persistent lumps or bumps that frequently bleed.
• Inflamed eyelids
• Lesions that have an irregular border or that become larger or more elevated
• An unexplained loss of eyelashes.
• A change in the shape of the pupil.

Intraocular Cancer

Melanomas can occur inside of the eye too and they can be difficult to detect. Signs and symptoms include:

• A sensation of flashes or specks of dust in the vision (floaters).
• A growing dark spot on the iris.
• A change in the shape of the pupil.
• Poor or blurred vision in one eye.

Please visit your optometrist or general practitioner if you experience any signs or symptoms mentioned in this article.

Protect The Eyes From UV Damage All Year Round

A pair of good quality sunglasses is one of the best defences against eye and eyelid damage. The colour and depth of the tint are unrelated to the amount of protection the lenses afford. The important thing to look for is the “UV 400” mark. Lenses marked as such will absorb or block light with wavelengths up to 400nm. Make sure the sunglasses have a CE mark too to be sure they conform to European standards. The sunglasses should be large enough to shield the eyes and surrounding areas; a wraparound style is ideal.  A hat with a brim of eight centimetres or more will block as much as half of all UVA and UVB rays too.