When pollen counts are high and your eyes get irritated and red, it may be tempting to wear your sunglasses all day long. However, there are other short-term solutions many people turn to. Eye-whitening drops can be purchased over the counter and help you battle red eyes caused by allergies, dryness, digital eye strain, dust and more.Many people who regularly deal with red eyes may turn to eye-whitening drops to avoid discomfort or embarrassment. But what are these eye-whitening drops actually doing, and are they safe? We spoke with two eye doctors to find out.How do eye-whitening drops work? Upgrade your inbox Get cnet insider From talking fridges to iPhones, our experts are here to help make the world a little less complicated. Optometrist Dr. Meenal Agarwal says, "Eye-whitening drops work by constricting the blood vessels on the surface of the eye, reducing redness and making the eyes appear whiter." In addition to tightening blood vessels, Agarwal says that eye-whitening drops "reduce blood flow to the area," which "reduces redness and makes your eyes appear brighter."What exactly are you putting in your eyes? Dr. Ashley Hayden, board-certified eye surgeon and co-founder of GentleDrop, tells us, "The active ingredient in most eye-whitening drops is tetrahydrozoline, which tightens blood vessels for a few hours. It's similar to Afrin nasal spray."While eye-whitening drops can make your eyes white for a few hours, you should not become reliant on them. According to Dr. Laurie Barber, a spokesperson for the American Academy of Ophthalmology, in a 2018 news article for the organization, "I would prefer that patients not use an eye-whitening drop on a regular, long-term basis A person should get evaluated for red eyes before using eye drops on a regular basis."If you do temporarily use eye-whitening drops, be sure to follow the manufacturer's recommendations on your specific product. If you already use prescription drops, you should talk to your doctor before introducing any new over-the-counter eye drops. Photo travelling people sports/Getty ImagesAre eye-whitening drops safe?When used as directed, eye-whitening drops are safe for most people. "These drops are safe to use infrequently to improve the appearance of a bloodshot eye," states Hayden. "However, they do not treat any problems and can cause worsening redness as the medication wears off. Regular and repeated use is discouraged."It's worth noting that the safety of eye-whitening drops may depend on your personal eye health. To that point, Agarwal warns that some people should avoid eye-whitening drops. She says the vasoconstrictors -- an agent that causes narrowing of the blood vessels, like tetrahydrozoline -- in eye-whitening drops can increase eye pressure and may not be safe for people with glaucoma.Additionally, the doctor says that patients with "chronic dry eyes, allergies or sensitivities to preservatives, high blood pressure and cardiovascular issues are advised against using these drops." She adds that pregnant people should also avoid eye-whitening drops.Do eye-whitening drops have side effects?One of the most common side effects of eye-whitening drops is "rebound redness." This phenomenon happens when your blood vessels dilate even more than usual when the eye drops start to wear off. Dr. Hayden calls this "vasodilation, or expansion of blood vessels." She says this side effect could be more long-term than the initial benefits of the drops.Another side effect of these drops is that they could mask more serious eye problems. For instance, if you have an eye infection like conjunctivitis (pink eye), eye-whitening drops may hinder you from noticing the seriousness of the issue. The drops are not medicinal and will only put a bandage on underlying eye illnesses.Agarwal advises that the side effects of eye-whitening drops can include "irritation, increased redness or reactions to preservatives in the drops." She warns that using the drops too often could mask underlying issues such as "eye strain, dryness, allergies, infections or inflammation," and states, "For these conditions, it's important to consult an eye doctor for proper treatment." BananaStock/Getty ImagesWhat about blue-tinted eye drops?Blue-tinted eye drops, sometimes simply called blue eye drops, are an alternative to regular eye-whitening drops. This type of product contains a blue dye. Agarwal explains that the dye "enhances the whites of the eyes by counteracting yellow tones, without relying on vasoconstrictors." In other words, these drops don't interact with your blood vessels.Blue-tinted drops are not generally considered as safe or effective as other eye-whitening drops.Agarwal advises, "I generally don't recommend them due to potential sensitivities to dyes. Additionally, they don't treat underlying causes of redness and overuse can lead to irritation and worsen the original issue."In addition to potentially irritating your eyes, it's worth noting that blue drops could dye the skin around your eyes. If you wear contacts, the dye could also ruin your lenses.When to see an eye doctorIt's one thing to use eye-whitening drops occasionally to counteract high pollen counts or dry outdoor conditions. It's quite another to use them as a long-term solution to red eyes. Both doctors we spoke to urge people to see a doctor if they are using these drops for anything other than an occasional solution.As for when to call your doctor, Hayden says, "If you have pain, changes in vision, light sensitivity or a watery eye that isn't improving, please see an eye doctor." She also says that any side effects from eye-whitening drops may require a visit to a physician. According to Hayden, "If the side effects last more than an hour or if you feel faint or dizzy, go see an eye doctor."Agarwal agrees that the best solution for frequent red eyes is a visit to the doctor. She explains, "Chronic redness may result from dry eyes, allergies or eye strain. Redness accompanied by pain, vision loss or light sensitivity should be evaluated by an eye doctor." PeopleImages/Getty ImagesHow to naturally make your eyes look brighter and healthyThere are a number of ways to make your eyes look brighter without turning to any over-the-counter, eye-whitening products. Agarwal recommends the following tips for naturally bright eyes:Stay hydrated: Drink enough water throughout the day. When your body is hydrated, so are your eyes.Get enough sleep: Getting the recommended seven hours of sleep can keep eyes from being dry and red in the morning.Reduce eye strain by taking computer breaks: Looking at a blue light for too long, including from a computer or mobile device, may cause pain or redness. Take hourly breaks.Wear sunglasses outdoors: In addition to wearing sunscreen to keep your skin safe, protect your eyes with proper eyewear.Practice good eyelid hygiene: Gently cleaning your eyelids with a soft washcloth can remove irritants from the area and stop them from getting into your eyes.Manage allergies: Talk to your doctor about how to keep seasonal allergies at bay to avoid redness.The doctor adds, "I always recommend my patients keep a bottle of preservative-free artificial tears by their nightstand to use morning and night. This will help keep your eyes moist and reduce dryness or redness that may develop later in the day."Hayden also recommends artificial tears. Additionally, she says that eyelid scrubs and warm compresses can help your eyes stay clear and hydrated.The bottom lineEye-whitening drops are mostly safeas long as you don't rely on them daily for a long period of time. Long-term eye redness is often indicative of an underlying issue that requires medical intervention from a doctor. If you experience any rebound redness, pain or dizziness from using these eye-whitening drops, the experts we spoke to say you should discontinue use and talk to your doctor. As for blue-tinted drops to whiten your eyes -- it's best to avoid them.