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is it really dangerous to look at the sun during a solar eclipse? and other tips to keep your eyes safe
it's always a good time revisit questions about the impacts of the sun on our eyes and how to properly protect our vision.
a total solar eclipse is expected to be visible to canadians in parts of ontario, quebec, new brunswick, nova scotia, newfoundland and p.e.i. on monday, april 8, 2024.
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we all know how to protect our skin from the sun’s damaging rays — which is vitally important to avoid skin cancer — but we don’t always think about how ultraviolet exposure can affect our eyes. as we age, many of us may experience some vision loss. prolonged exposure to the sun, however, can speed that up by raising the risk for cataracts, which is a cloudiness on the lens inside the eye.
but that’s only one example of how the sunshine can harm our precious orbs. dr. phil hooper, the president of the canadian ophthalmological society, offers some interesting facts about our eyes, like why we see spots when we look at a bright light, as well as tips on how to protect our peepers from pool water, airplane air and why it’s risky to watch a solar eclipse.
a total solar eclipse was visible to canadians in parts of ontario, quebec, new brunswick, nova scotia, newfoundland and p.e.i. on monday, april 8, 2024. this means the moon moved between the earth and the sun, blocking out the sun from view below.
the next total solar eclipse is not expected until 2044, but it’s always a good time revisit questions about the impacts of the sun on our eyes and how to properly protect our vision.
is it really dangerous to look at the sun during a solar eclipse?
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it is possible to develop damage to the retina by exposure directly to the sun but that’s usually found in someone who has lost consciousness or is in an altered state of consciousness from drugs or other things. normally, we would look away from the brightness of the sun.
during an eclipse you have to be very careful. you really shouldn’t be looking at the sun at all — you should look at it indirectly. blindness would come from looking at a solar eclipse or directly into the sun. there really isn’t anything you can do to protect your eyes. even wearing dark welder’s glasses has not been proven to be safe. in a severe situation, like so-called solar retinopathy, where someone has looked at an eclipse, they would have a blind spot in their vision that may or may not recover depending on the amount of damage done.
temporary damage to the surface of the cornea can cause eyes to water and feel like you’ve got sand or grit in them so you tend to blink a lot more. you may have a bit of a headache as well.
how does the sun damage our eyes?
with long exposure to excessive amounts of sun, particularly in a dry climate, the cornea, which is the transparent tissue that protects the iris and pupil, can actually start to scar. the lens absorbs most of the ultraviolet rays that enter the eye and, over time, repeated exposure to those rays can accelerate the development of cataracts.
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most of the damaging rays, though, are removed by the time the light gets to the lens and passes down to the retinas, so there isn’t as big an issue in terms of damage to the retina with sun exposure. [research hasn’t] really been able to correlate an increased risk of conditions like macular degeneration with sun exposure over the years, but there is a clear association with the development of cataracts.
how do our eyes adjust going from bright to dim light?
the chief mechanism we have to regulate the amount of light going in the eye is the iris, which gets bigger and smaller depending on the amount of light that we’re exposed to. [we have an] aversion reflex, in that it’s just uncomfortable enough to look into bright light that we look away or close our eyes to protect them.
why do we see spots in our eyes after looking at a bright light?
when we look into a bright light, [the eye’s] pigments are bleached and you can no longer react to light or realize light is there until they’re regenerated. if it’s a short exposure, like a flash bulb going off, it takes a matter of a few seconds. but with longer periods of exposure to brighter light, that whole process takes much longer.
how extra careful should you be after cataract or laser surgery?
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in terms of light exposure, not so much. cataract develops very slowly; it actually lets less and less light through the lens of the eye. so when the lens is removed and an artificial lens is placed in cataract surgery, the vision is much brighter, the colour perception changes immediately. so from a light point of view, there really isn’t a particular concern.
with respect to laser corrective surgery, where they reshape the cornea, yes, you’re much more light sensitive for a period of time afterward. so [follow] restrictions in terms of the amount of light exposure for a few days.
how sensitive to sun exposure is the skin around the eyes?
like skin everywhere, the skin on the face, particularly the eyelids, is very susceptible to sunburn. so use of sun protection on the eyelid region is very important. the skin is so thin, it’s not pigmented there, and the sun’s rays penetrate. the eyeball protects, to some degree, the upper part of the eyelid but the lower part is very exposed. and with repeated exposure to uv rays, there is a chance of developing skin cancer as people get older.
sunglasses are important for protection. does the colour of the lens matter?
the only advantage of grey is that it is colour neutral. brown or green sunglasses change your colour perception, grey lenses don’t. but there isn’t anything intrinsically better about grey than another colour.
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the key thing with sunglasses is that the lenses should be large enough that they block the light from getting at your eyes. and the frames should be big enough that they block the light coming in from the side. so we want a fairly heavy frame with good side protection. virtually all of the lens on the market now are rated for uva and uvb [protection].
along with sunglasses, the use of a broad-brimmed hat can cut the indirect rays that get around the glasses and also protects the skin on your face.
how do you avoid your eyes getting dry and itchy aboard an airplane?
the first thing you can do is make sure the nozzle above your head isn’t blowing air directly on your face. second, if your eyes start to feel dry, closing them for a minute or two will rehydrate them. the final thing is to bring along some artificial tears to use.
which is worse for your eyes: sea water or pool chlorine?
pool chlorine is a real irritant that will cause red or burning eyes for a period of time. some people are more sensitive than others, but it doesn’t do any permanent harm. similarly, sea water can be irritating to the eyes, but unless there’s some other chemical or something in the water, it shouldn’t cause any permanent harm.
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people who wear contact lenses shouldn’t have them in when swimming in either pool or sea water because they can literally stick to the eye and be very difficult to remove and very uncomfortable. take them out and allow your eyes to settle before you put them back in.
article originally published on may 16, 2023. last updated june 27, 2024.
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