You know what the sun can do to skin, right? Many a parent has learned the hard way. A few carefree hours in the sun – without sunscreen – can wreak havoc on the tender skin of children.
Well, their eyes are just as delicate. But while many parents religiously slather on the sunscreen, very few are just as careful with their kids’ eyes.
So, if you’re ready to go out and buy your kids sunglasses, read on to find out what to look for, and what to avoid. [1]
Sources of UV The main source of UVR is sunlight. Artificial lighting contributes to a lesser extent but may increase with the advent of energy efficient light sources.
Ambient UV: direct radiation, scatter, and reflection
Direct sunlight only partly contributes to ambient UV. Under average conditions, more than 50% of ocular exposure comes from scattering and reflection from clouds and the ground.
The World Health Organisation’s solar ultraviolet index (UVI), an international index of UV burden assesses risk of UV damage to the skin. Several studies have shown that this is not a valid indicator of eye protection and potentially misleading.
Identifying absorption and transmission of UVR within structures of the eye is key to understanding potential damage.
UV transmission is strongly dependant on age. Below 9 years of age, a larger portion (2-5%) of UVA is transmitted by the cornea and the lens. Significant inter-individual differences have also been shown.
Acute and chronic damage to the eye by UV and visible light has been extensively studied, including epidemiological studies, with greater significance on chronic exposure.
Cornea
The cornea is most exposed, with the greatest level of UVR absorption from direct irradiation. In addition oblique rays are reflected across the cornea and anterior chamber into the limbal area leading to elevated pathologies in this area. Most common diseases: Pterygium, pinguecula, climatic droplet keratopathy.
Cortical cataract
It is known that UV light induces cataracts with a damage threshold at 350 nm of 60 mJ/cm2. With growing and aging populations and other changing demographic factors the incidence and prevalence of cataracts will increase. Reducing the risks that can lead to cataracts is therefore important.
Dry eye, premature presbyopia, AMD
Decreasing tear film production linked to ageing, reduces UV absorption and antioxidant production by tears.
The association between UVR and AMD remains controversial. Blue light is a more significant contributor to development of AMD.
UV related skin aging and diseases of periorbital skin
The acute response of the skin to UV is inflammation (sunburn). Clinical symptoms include erythema, swelling, pain and pruritus.
Chronic effects include photoaging and photocarcinogenesis. Some clinical signs of photoaged skin include dryness, irregular pigmentation, lentigines, wrinkling and inelasticity. The delicate periorbital skin is particularly susceptible to effects of photoaging.
Mitochondrial DNA is a chromophore for UVA and UVB and subject to damage by UVR. DNA deletions are increased by up to 10-fold in photoaged skin compared to sun-protected skin of the same individual.
Photocarcinogenesis includes the development of actinic keratosis, squamous cell carcinoma, basal cell carcinoma, and malignant melanoma. 5% to 10% of skin cancers are appearing on the eyelids.
SPF measures sunscreen protection from UVB rays, the kind that cause sunburn and contribute to skin cancer. SPF does not measure how well a sunscreen will protect from UVA rays, which are also damaging and dangerous. Dermatologists recommend using a SPF15 or SPF30 sunscreen.
Higher SPFs don't give much more protection.[2]
SPF is an abbreviation for "sun protection factor." A sunscreen's protection factor (SPF) is figured by comparing how long it takes sunscreen-protected skin to burn to the length of time it takes unprotected skin to burn. The higher the SPF, the more protection you get against UVB rays.[3]
Sunglasses should be the first thing we reach for after applying sunscreen then, maybe a hat. With concerns over possible thinning of the ozone layer, the need to protect our bodies from UV exposure is becoming a growing concern.
It's more than a concern over sunburn. Our eyes as well as our skin need protection from UVA and UVB rays. These harmful invisible light rays are implicated as one of the leading causes of cataracts and macular degeneration. Children are of particular concern and should wear sunglasses for their protection as sun damage is cumulative with most ill effects occurring before age 25. Even on cloudy days, UV rays can be just as damaging to the eyes. Don’t save sunglasses for only the brightest days. Wear them when spending any time outdoors. eResearch by Navid Ajamin -- spring 2016
Quality ophthalmic sunglasses will give 100% protection against UVA and UVB. There are different types of ophthalmic lenses one should consider when purchasing sunglasses. Glass lenses are more scratch resistant but they are heavier and can shatter if hit with an object. Plastic lenses are lighter and available in more colors and coatings. Polycarbonate lenses offer the most protection from breaking and are recommended for sports and should be considered for active children.[4]
skin around our eyes is ten times thinner than the skin on our face and Sunscreens are not tested to be used around eye area ,So it is better not to use sunscreens for around the eyes.
The heat can be very harsh on your eyewear specifically if you have a plastic frame. What ever you do, remember not to leave your sunglasses in the car! If it’s nearing 100 degrees outside your car, it’s probably approaching 200 inside the car.
Excessive heat can cause your prescription lenses to peel or permanently smudge your anti-reflective coating. This is true even for the more durable forms of anti-reflective coating like Kodak brand Clean & Clear.
The heat can cause your plastic sunglass frame to actually warp, essentially melting the plastic. Now this does not look like some bad B-rated horror movie where your glasses literally liquify, usually it makes the frame flatten out and get wider. This of course produces some fitting problems for the wearer as the glasses will then be consistently falling off.
Take extra care of your eyewear in the harsh summer heat. Keep yourself (and your glasses) cool!
Choose a sunscreen labelled broad spectrum or high protection against UVA and UVB so it offers balanced UVA and UVB protection.
Do not stay in the sun too long, even whilst using sunscreen, as no sunscreen can provide 100% protection.
Use a high protection sunscreen and re-apply frequently and generously, especially after perspiring, swimming or towelling.
In sunny weather, seek shade between 11am and 3pm when UV is at its strongest.
Cover up with clothing and don’t forget to wear a hat that protects your face, neck and ears, and wear good quality UV protective sunglasses.
Never let your skin burn and remember, a tan is a sign of sun damage to the skin.
Children have more sensitive skin and need extra care – use sunscreen, clothing and shade. Keep babies and young children out of direct sunlight.
Reference:
1.vsp.com 2.badgerbalm.com 3.sharecare.com 4.eyecareassociatesnc.com 5.vivawoman.net 6.pointsdevue.com 7.drtavel.com 8.uvistat.com
وبلاگ تخصصی عینک شامل مجموعه مطالب پزشکی است که اطلاعات مفیدی در رابطه با عینک , چشم، لنز، سلامتی چشم و راه های پیشگیری از بیماریهای چشمی، کنترل و درمان آن را در اختیار شما کاربر محترم می گزارد.
