Your eyes can do some pretty strange things. An eyelid starts twitching for no apparent reason. You look at a bright light and suddenly sneeze. You rub your eyes and see stars.
Most of these everyday eye quirks have perfectly reasonable explanations. Others can signal it’s time to have your eyes checked.
Here are answers to eight common questions about your eyes.
1. Why does my eye keep twitching?
That annoying little flutter in your eyelid is very common. Eyelid twitching, sometimes called eyelid myokymia, is usually temporary and harmless.
Common triggers include:
- Stress
- Fatigue or lack of sleep
- Too much caffeine
- Eye strain
- Dry or irritated eyes
If your eyelid starts twitching, getting more sleep, cutting back on caffeine, taking regular breaks from screens, and addressing dry eye symptoms may help. In many cases, the twitch will disappear on its own within a few days or weeks.
An occasional twitch usually isn’t cause for concern. However, schedule an eye exam if the twitching persists for several weeks, becomes more frequent or severe, causes the eyelid to close completely, involves other areas of the face, or is accompanied by redness, swelling, discharge, or other eye symptoms.
2. Why do I see little spots or strings floating in my vision?
Those little dots, specks, cobwebs, or strings that seem to drift across your vision are called floaters.
Floaters are tiny clumps or strands within the vitreous, the gel-like substance that fills the inside of your eye. They cast shadows on the retina, which is why you see them moving across your field of vision. They can be especially noticeable when looking at something bright and uniform, such as a blue sky or white wall.
A few occasional floaters are common, particularly as we age. But a sudden increase in floaters—especially if you also see flashes of light or a dark curtain or shadow in your vision—can be a sign of a retinal tear or retinal detachment and should be evaluated promptly.
3. Why do bright lights make me sneeze?
Step outside into bright sunshine and suddenly need to sneeze? You’re not alone.
It’s called the photic sneeze reflex, and it causes some people to sneeze when they’re suddenly exposed to bright light. The exact mechanism isn’t fully understood, but it’s thought to involve crossed signals between nerves that sense bright light and those that trigger a sneeze.
The tendency also appears to run in families. So if stepping into the sunshine makes you sneeze, there’s a chance someone else in your family does the same thing. It may be strange, but for most people, the photic sneeze reflex is harmless.
4. Why do my eyes water when they’re dry?
It sounds contradictory, but watery eyes can actually be a symptom of dry eye.
When the surface of the eye becomes too dry or irritated, your eyes may respond by producing a rush of reflex tears. Those tears can leave your eyes watering, but they don’t necessarily have the right balance of oil, water, and mucus needed to keep the eye comfortably lubricated.
Dry eye can have many causes, including aging, certain medications, environmental conditions, prolonged screen use, contact lenses, and problems with the glands that help maintain a healthy tear film.
If your eyes frequently feel dry, gritty, irritated, or watery, an eye exam can help determine what’s causing the problem and what may help.
5. Why do I sometimes see an afterimage after looking at something bright?
Look at a bright light or a high-contrast image and then look away, and you may continue to see a faint version of it for a short time.
That’s called an afterimage. It happens because the light-sensitive cells in your retina temporarily adapt to what you’ve been looking at. When you shift your gaze, those cells need a little time to readjust, causing the image to linger briefly.
Temporary afterimages after looking at something bright are generally normal. However, visual effects that appear without an obvious cause, happen frequently, last unusually long, or are accompanied by flashes, new floaters, or other changes in vision are worth discussing with an eye doctor.
And remember: never look directly at the sun, even briefly, as doing so can permanently damage the retina.
6. Why is it getting harder for me to read things up close?
Have you noticed yourself holding menus, books, or your phone farther away to see them clearly? Or needing brighter light to read the fine print? If so, you’re not alone.
As we age, the natural lens inside the eye gradually becomes less flexible, making it harder to focus on things up close. This age-related change, called presbyopia, typically becomes noticeable sometime after age 40. It happens to nearly everyone eventually, even people who have never needed glasses before.
That’s why reading glasses become so common as we get older. Because presbyopia affects so many people, reading glasses are available without a prescription. These glasses provide the same magnifying power in both lenses and may work well if both eyes need similar correction and you otherwise see clearly at a distance.
However, over-the-counter readers aren’t right for everyone. If your eyes require different prescriptions, you have astigmatism, or you’re experiencing other changes in your vision, prescription glasses may provide clearer and more comfortable vision.
And remember, even if a pair of readers does the trick, regular eye exams are still important for monitoring your eye health and detecting conditions that may not cause noticeable symptoms in their early stages.
7. Why do onions make my eyes water?
You can blame a little chemistry for this one. When you cut into an onion, you break open its cells and trigger a chemical reaction that releases an irritating compound into the air. When that compound reaches the surface of your eyes, it irritates the nerves there.
Your eyes respond the way they often do when something irritating gets in them: they make tears to help wash it away. That’s why chopping an onion can leave you crying even when dinner is going perfectly well.
8. Why do I see stars when I rub my eyes?
Have you ever rubbed your closed eyes and seen little flashes, stars, or colorful patterns?
Pressure on the eye can stimulate cells in the retina, creating the sensation of light even though no actual light is entering the eye. These visual effects are called phosphenes.
Seeing a few stars while rubbing your eyes is different from experiencing flashes of light that appear spontaneously. An eye doctor should evaluate new or unexplained flashes—especially when accompanied by new floaters or changes in vision.
And while rubbing tired or itchy eyes can feel good for a moment, frequent or aggressive eye rubbing can cause irritation and is a habit best avoided.
Your eyes can tell you a lot
Most of the strange things our eyes do from time to time have simple explanations. An occasional eyelid twitch, a few seconds of an afterimage, or watery eyes while chopping an onion usually isn’t something to worry about.
The key is knowing when something is new or different. Sudden vision changes, new flashes or floaters, persistent symptoms, eye pain, or noticeable changes in how well you see deserve attention.
If something about your eyes or vision has you wondering whether it’s normal, the team at Iowa Eye Center can help.
Schedule an eye exam at Iowa Eye Center
Regular eye exams do more than determine whether you need glasses or an updated prescription. They also give your eye doctor a chance to evaluate your eye health and identify potential problems, sometimes before you notice symptoms.
If you have questions about changes in your eyes or vision, call Iowa Eye Center at 319-362-3937 to schedule an eye exam, or request an appointment online.
