As years go by and we are getting older, our vision naturally decreases.
Some people have never felt the necessity to wear glasses or contacts, but others have found that their vision is diminished mainly as they age.
The good news is, you can always seek help in consuming a variety of vision support supplements. Among other dramatic benefits, they even claim to fix poor eyesight, improve your vision, or even reverse blindness.
Unfortunately, not all vision supplements are made equal. There are many containing unpublicized dosages of suspicious ingredients or built-on junk science.
As experts in the vision supplements field, we present you with our well-researched rankings of the best eye health formulas and vision supplements currently available online.
Best Eye Vitamins for Vision Support
In creating our research, various tests and analyses of the most popular vision supplements were performed. After contacting manufacturers and comparing lab reports, we went through thousands of peer-reviewed studies to verify the advertised advantages of consuming the top vision supplements.
Here are the most reputable vision supplement brands on the market today:
According to the approved website, Vista Clear is a supplement for vision health, built on an “ancient Aboriginal recipe.” For thousands of years, to see clearer, ancient Australian folks have used this popular recipe. The company affirms that a single Aussie tribe has an eyesight four times sharper than the standard person’s eyesight.
Vista Clear supplements consist of 26 antioxidants, vitamins, herbs, and minerals. They also include unique ingredients like Bacopa monnieri, chamomile, skullcap, lemon balm, hawthorn, and St. John’s Wort. This famous Aboriginal diet consists of unique vitamins and minerals that are not registered in a conventional regime. As a result, they are frequently found in other vision health supplements.
Vista Clear emphasizes low portions of ingredients, stating that their formula will “work wonders for you.” Their other supplements focus on high dosages featuring a few designated ingredients.
This product is shockingly expensive, matched to other formulas on this list, but every penny is worth spending.
Eagle Eye 911
This is a vision health supplement provided by PhytAge Labs. Eagle Eye 911 delivers 2x the protection of a standard vision supplement. Therefore, it is marketed as an ideal formula for eye health and vision support. PhytAge claims that their Eagle Eye 911 provides advantages we rarely see with other vision health supplements. Such are improving overall vision, supporting the retinal membrane, developing optimal eye function, and helping reduce eye pressure.
With a subtle blend of components added to their formula, PhytAge 911 has achieved dramatic benefits. The most significant portion of ingredients in Eagle Eye 911’s supplements consist of L-taurine, NAC (200mg), quercetin (100mg), and grape seed (100mg).
Working as antioxidants, these ingredients can insignificantly support the vision, and it backs up all acquisitions with a money-back guarantee.
Advanced Bionutritionals Advanced Vision Formula
Advanced Bionutritionals Advanced Vision Formula can be a proud owner of a vision and eye health formula with over twelve ingredients.
According to many consumer reviews, this supplement, among other benefits, has assisted many users to “see much better,” clear up eye health issues and enhance their night vision. A female patient also suggested that her doctor was surprised by the significant improvement of her eyes after using this Advanced Vision Formula.
The Advanced Vision supplement is derived from ingredients found in other product formulas. Such are astaxanthin, lutein, bilberry, and zeaxanthin. We also don’t see some components in different formulas, like beta-glucan, cognizin, Ginkgo Biloba, and L-taurine, generally found in nootropics. The blend of compounds can support vision by supporting cognition.
Provisine offers quality products similar to those of Vista Clear, ReVision, Divine Vision 13, and other supplement brands in this list. This supplement was created by a 32-year-old industry expert in “treating every vision condition known by science” optometrist, called Dr. Dean Avant. On the internet, we could find only limited information on Dr. Avant.
Provisine is one of the few vision supplements on this list that explicitly improves your eye vision. It contributes to overall eye well-being and improvement and carries a secret blend of ingredients and dosages.
No matter how bad your vision loss is, Provisine guarantees to help you retrieve it if you had perfect vision before.
According to Provisine.com, this supplement is a completely natural solution that ensures every patient with a new and improved 20/20 vision – within weeks.
Vitamins and antioxidants are used to target vision well-being. For that matter, Eyesight Max applies unique ingredients to support vision in a distinguishable way. This is a supplement that picks out the real cause of vision loss and acts upon it accordingly.
Same as Provisine, Eyesight Max especially claims to upgrade your vision like few other supplements included here. Their official website assures that this supplement will give everyone a clear 20/20 vision who uses their product in just a few weeks. No exercises, surgery, prescription drugs, or any other effort – the supplement does the job on its own.
The company producing this supplement guarantees to work no matter if your vision was lost caused by cataracts, type 2 diabetes, eye damage, aging, macular degeneration, or glaucoma. Still, the manufacturer provides little information on the product components or dosages.
Divine Vision 12
This product is a first-class vision supplement from Divine Body Health. Purportedly, this supplement uses Biblical ingredients to support the vision vitally. The creators are mysteriously vague about what’s inside the Divine Vision 12 formula, how it functions, or how people can anticipate its results following consumption.
A 180-day money-back guarantee backs all purchases of Divine Vision.
At $69 per bottle, the Divine Vision 12 is saltier than other options on this list. Yet, to justify the high cost, the manufacturer provides limited information. If you don’t experience certain benefits in the first six months of consuming this formula, you are qualified for a refund.
Built on a “6-second trick”, ReVision is a nutritional supplement that can reportedly “restore perfect eyesight tomorrow.” Although it comes at lower doses than the other competing supplements mentioned above, ReVision is priced at $69 for a one-month supply. In these current months, the producers of ReVision have advertised a new version of the same supplement, called ReVision 2.0.
The company claims that this ReVision 2.0 formula is 100 percent natural, safe and effective.” According to the manufacturer, you can support vision and brain function by taking these supplements from 3 to 6 months.
Zenith Labs Vision
Zenith Labs outdid themselves with the advanced support formula for Vision 20. This supplement can support the healthy vision of older adults and seniors.
According to Dr. Ryan Shelton, the man responsible for formulating this vision supplement, Vision 20 is helpful because of its “perception detoxifiers.” He insists that his formula is not a temporary eyesight solution. It’s an all-natural product, supported by factual research to improve vision in a significant way.
As humans grow older, the ROS toxins are thickening and obscure the lens of the eye. Therefore, two of the most investigated ingredients for eye well-being and vision in this supplement – carotenoids and zeaxanthin – can essentially fix vision loss.
PureHealth Research Complete Vision Formula
This complete vision formula from PureHealth Research is a stellar vision support supplement, priced at $49 per bottle. This supplement uses vitamins C and E, copper, zinc, eyebright extract, lutein, bilberry, and zeaxanthin to support and enhance vision.
Proven by scientists, these essential natural constituents in the Complete Vision Formula support and maintain eye health and provide the body with the necessary ingredients.
Many customer testimonials published on the PureHealth Research website state that some customers have genuinely adjusted their vision after using the Complete Vision Formula.
One woman claims that thanks to the Complete Vision Formula, she experienced a clearer vision in just three weeks of using the supplement. At the same time, other users have assured that the supplement contributed to them seeing far better than before.
Interestingly, many consumers of this supplement required no glasses after taking their regular doses.
Vision MD from 1MD is a nutritional supplement formulated by actual medical experts. It contains Lyc-O-Mato lycopene, OptiLut with lutein and zeaxanthin, and EVTene mixed carotenes; three proprietary formulas studied for their effects on human vision. As reported by 1MD, the recipe is “revolutionary,” and with it, the aid of proper vision and eye health support are clinically proven.
This supplement works simply: the nutrients validated by the National Eye Institute were checked by 1MD, the supplement that exceeded these endorsements was created.
By implementing astaxanthin and vitamin E to the mixture of ingredients, among other benefits, VisionMD can also improve visual acuity, help prevent oxidative cellular damage, and promote overall vision health.
Performance Lab Vision
This eye support supplement, called Vision, claims to give you crystal clear visual performance while supporting your overall eye health.
After consuming the formula, you can enjoy movement apprehension, high-speed detection, and even improved “night vision,” according to the brand statement. This supplement also helps minimize the vision-impairing effects of dazzle, simultaneously fighting the macula-damaging outcomes of blue light rays.
To achieve these benefits, Vision consists of ingredients like bilberry extract, blackcurrant extract, zeaxanthin, astaxanthin, and lutein, all found in similar products on this list. The supplement contributes to eye health by introducing solid content of anthocyanins – detrimental to eye wellbeing.
This supplement is one of the most debatable ones on this list when it comes to the price.
Nuzena Vision Support +
The Vision Support + from Nuzena is an eye health supplement that aims to help and protect from AMD. Among other benefits, it also supports natural vision and aids macula health. It is effortless to compare other supplements sold nowadays in the virtual world since Vision Support + is not hiding its dosages and ingredients.
Its supplement contains high zinc oxide, biotin, vitamin E, vitamin C, vitamin B1, vitamin B2, vitamin B3, vitamin B12, and many other common nutrients.
The product also boasts a “Vision Support + Blend” featuring lutein, bilberry extract, NAC, alpha-lipoic acid, zeaxanthin, eyebright, quercetin, and other proven ingredients. Vision Support + may bolster vision and eye health in multiple ways.
It helps people be protected against age-related macular degeneration (AMD) and efficiently targets other common eye problems.
This supplement, without doubt, comes with the most attractive wrap-up compared to any other on this list.
Lutenol offers a vision support formula aiding healthy eye function, lens, retina, and macula health. Customers can support their general vision well-being by taking two VitaPost Lutenol capsules a day since lutein and vitamin A are the essential antioxidants this supplement is packed with.
This supplement ensures ameliorated vision and prevention of further eyesight issues. It also comes with zero side effects, as per customer reviews on Lutenol.com. According to the manufacturer, Lutenol is made of ingredients like bilberry and anthocyanosides specifically supporting the retina.
Meanwhile, Lutein and zeaxanthin are concentrated naturally in a healthy visual system (eyes and brain included), and a small dose of both nutrients is delivered by the supplement itself.
The formula has been carefully crafted to blend more unique ingredients, like carotenoids and herbal extracts, alongside high-quality minerals and vitamins.
Bonus Vision Guide #1: Sniper Vision System
Taking care of a good vision isn’t just consuming certain supplements. It’s also about adjusting lifestyle factors and diet. With the help of the Sniper Vision System, you can discover different strategies to improve your vision drastically. These include simple tricks and exercises you can perform and dietary changes you can make to enhance your vision.
Everyone can achieve bulletproof 20/20 vision with this supplement. This is also achieved by implementing the lessons in the guide provided by Dr. Richard Simmons, the man who produced the Sniper Vision System.
Surely, snipers need incredible vision to be capable. As recommended by Dr. Richard Simmons, from the strategies used by many snipers to improve their vision, you can improve yours with the Sniper Vision System too.
The Eye Test Home kit and Clear Eyes Protocol bonus guides are also included with every order you make.
Bonus Vision Guide #2: Natural Vision System
According to the nationalvisionimprovement.com site, the Natural Vision System guide is an essential collection of videos and eBooks that can significantly better your vision using natural therapy treatments. By implementing these treatments in your everyday life, you can dramatically increase your vision abilities.
The Chief Health Researcher produced this System at National Vision Improvement, Dr. Michael Tonka. He claims that his eye health advice can help fight farsightedness, nearsightedness, cataracts, eye imbalances, eye pressure, macular degeneration, macular edema, eye strain, and more. Dr. Tonka even claims that his guide can also help with the physical misshapenness of your eyes called astigmatism – something that no other eye health guide targets.
Bonus Vision Guide #3: Koori Vision Fix Protocol + Home Eye Test Kit
This outstanding vision treatment protocol was developed in partnership with two men named Koori and Jake Turner. According to KVisionFix.com, this protocol is a simple way to manage vision loss and upgrade your eyes to 20/20 clarity.
One customer states that he was nearly blind before following the recommended treatment protocols from the guide. With the help of this guide, people can come across a unique formula to bring back their 20/20 vision and improve their perception. This treatment is believed to work wonders with eyesight improvement only by consuming a green smoothie every morning.
Nowadays, it is stated that the Vision Fix Protocol and Home Eye kit are scientifically acknowledged to correct the failing eye vision and achieve an incredible 20/20 vision in less than three weeks. This is achieved by making foods, recipes, and smoothies using common ingredients in any supermarket or home.
How We Ranked the Best Eye Vitamins for Vision Support
There are no two vision supplements made equal. However, all related products claim to support vision in various ways. We used the following metrics to separate the worst and best supplements available these days:
Pricing and Value
We always prefer supplements that offer good benefits for their price range. Here, we arranged the vision health supplements in price from $30 to $80. Of course, with the help of the internet, everyone can find a broad range of cheaper or much more expensive vision health supplements. If you are interested in spending $80 for a vision health supplement, you should get ingredients worth the cost.
Honest Advertised Benefits
We are fully aware that the vision supplement industry can be filled with fraud. Promising that you can cure vision problems by taking a supplement, dramatically improve your vision overnight, and restore 20/20 vision. That can easily be a false claim made to eager consumers. For that matter, we created our ranking list considering only the best vision health supplements. We also emphasized the supplements offering transparent benefits while skipping over those making untruthful or shady claims.
Medical Advisory Board
Many supplement companies we featured have naturopathic doctors (NDs) or other PhDs as part of their advisory board. We emphasized the vision supplements formulated, prescribed, or approved by medical doctors because the best supplement companies should always have a supporting hand from medicine.
Few of the vision supplements contain the right ingredients but at the wrong dosages. Therefore, we listed the supplements using clinically-based dosages, including ones used in peer-reviewed research and trials.
Science-Backed Ingredients for Vision
We heavily emphasize supplements that use science-backed elements since you will be consuming these vision health supplements to boost your vision. To validate their effects on vision, some ingredients featured in the supplements have been considerably studied. Others, however, hold antioxidants that could support inflammation but note it is impossible just to enhance the vision overnight.
Every manufacturer’s market notoriety was essential to be mentioned and part of our rankings’ decision. Customers need to separate long-standing reputation manufacturers that create adequate supplements from those that low-priced source products overseas, relabel them, and sell them online afterward.
Moneyback or Satisfaction Guarantees
It is complicated to take the utmost care of your vision well-being. Not every supplement can have the same impact on everyone. Based on this logic, we prefer supplements that have satisfaction or a money-back guarantee. After all, some patients have physical vision impairments that can’t be recovered without surgery.
In creating our research on the best vision supplements on the market, we relied on trusted consumer feedback and online customer reviews from real customers – including independent reviews.
Do Vision Supplements Work?
Do vision supplements work, or is this one grand scam? Well, some eyesight support vitamins claim that they can improve and restore your perfect vision, while others only claim to reinforce it.
Many ingredients work as antioxidants in these supplements. Such are lutein, zeaxanthin, astaxanthin, vitamin E, and vitamin C. Since these healthy ingredients are also discovered in tremendous concentrations in the eyes, they have been shown to support vision in a significant way. It’s possible that a specific supplement can help you if your vision problems are linked to inflammation.
Nevertheless, your eyesight tends to worsen over time, primarily due to old age. Even so, some people will experience vision problems due to physical damage to the eye. Here, surgery will be a more suitable course of action than taking supplements.
While some vision supplements promise to improve vision in anyone, a vision supplement can’t reverse physical severe eye damage.
Side Effects of Vision Supplements
Like most supplements based on vitamins, vision supplements are not linked to some consequential side effects. But, if patients are using some additional medications for any medical condition not necessarily related to vision, they should consult with their doctor before deciding to try any supplement types, including these vision supplements.
All supplement companies and their manufacturers have to use dosages and ingredients Generally Recognized As Safe (GRAS) by the FDA and its specific ingredient-approved list. When used by healthy adults, these dosages are not connected with significant side effects, the FDA has concluded.
Customers should never experience side effects as long as they follow the recommended dosages and instructions.
Vision Supplement Benefits: What Is the Science Saying?
Behind every vision health supplement, there is always some scientific proof of quality. And the most popular quality ingredient in these vision well-being vitamin pills is Lutein, a carotenoid linked with anti-inflammatory outcomes. Lutein works the best for fixing eyesight because it’s an antioxidant that can manage inflammation in your body, especially the eyes and brain.
Many studies show that lutein can support cardiovascular health and cognitive function. Others have also linked the lack of lutein as the leading cause of blindness, vision loss, and age-related macular disease. In a 2018 study, researchers discovered that lutein could help improve multiple aspects of eye health.
Another study, conducted in 2017, found that the combination of zeaxanthin and lutein can be especially effective in supporting eye health. This combination can be found in milk, some fruits, and vegetables (especially leafy greens.) People are unlikely to be deficient in zeaxanthin and lutein if they have a balanced diet.
In many studies, the researchers have found that the consummation of lutein, zeaxanthin and other carotenoid ingredients positively impacts overall eye health. These natural chemicals are applied to quail the eyes and enhance the overall vision. Nevertheless, this combination of ingredients can provide crucial vision support for you, especially if you have a weak or imbalanced diet.
Zeaxanthin can work independently, without the help of lutein, playing an essential role in eye shape, as reported by the American Macular Degeneration Foundation (AMFD). The damaging effects of light have no impact on the eye’s retinae with the help of this ingredient. The compound also reduces the risk of eye degeneration, as per an AMFD study.
Vision supplements are filled with Bilberry extract, one of the essential fruit ingredients ever known. According to WebMD, this incredible extract has been popular for eye well-being since the Second World War, when The Royal Air Force Pilots devoured bilberry jam to improve their late-night vision. This notion persists, so the ingredient remains popular in promoting vision health.
But despite its great popularity, the bilberry ingredient hasn’t proved to possess any significant vision health advantages. One study even found it hard to compare the placebo effect the extract might have on consumers.
One more popular cognitive element found in vision supplements is Ginkgo Biloba. In one study from 1999, researchers examined the effects of this ingredient on eye health and found that one of them was increased ocular flow velocity. Subjects who took Ginkgo Biloba reported having experienced significant blood flow improvements in the eyes.
To support vision and perception, choline is used as a unique vision ingredient in many vision supplements. In 1998, researchers discovered that the brain processes optical data from the eyes. Therefore to perceive things better, people’s brain strength needs to be in perfect shape. The study gave several participants 1g of CDP-choline a day for 15 days straight. The VEP’s visually evoked potentials resulted in 30% improvement. All in all, it was concluded that choline could improve vision when taken in high doses.
Another popular vision supplement ingredient is Beta-glucan. Found in a 2013 study, a mixture of beta-glucan (from barley) and mushroom flavor can significantly reduce the glycemic response for people with diabetes. This means that all people with diabetes can eat food without experiencing high blood sugar spikes. For that reason, it is entirely safe for all people with diabetes suffering from blurred vision to consume beta-glucan-based vitamin pills.
Vision Supplement FAQs
Q: What is decreased vision?
A: Decreased vision is suppressed vision that negatively interferes with everyday activities like driving or reading. Medicine states that vision below the normal range (20/70 or worse) is impossible to fix with conventional glasses or contacts – only with surgery.
Q: What is legal blindness?
А: Legally blind people might still have partial vision. If the central acuity is lower than the perfect 20/20 vision, people are considered not completely but legally blind.
Q: What do vision measurements show?
A: Also known as visual acuity, these measurements show the size of fonts people can read from a distance of twenty feet. Based on a Snellen chart, 20/20 vision is considered the perfect vision. This indicates that people can identify letters and symbols in all font sizes, from a 20 feet distance or closer.
Q: Does aging result in a risk of vision loss?
A: Absolutely. The risk of vision loss increases as we age. Studies show that visual impairments and the prevalence of blindness are increased across all racial and ethnic groups.
Q: Are the ‘spots’ floating around the eyes a normal appearance? Should I be worried?
A: Eye floaters and spots are a common and typically harmless occurrence. If you have any questions or concerns about your eye health, please schedule a regular eye check with your physician.
Q: Can I hurt my eyes working on my computer all day?
A: Radiation is emitted from computer screens, and it can theoretically hurt your eyes. Also, prolonged usage of computers can damage the eyes, especially when not taking the extra step to protect oneself, like using blue light filters late at night and taking regular breaks from the screen.
Q: How can someone reduce the risk of vision loss?
A: Half of the visual impairments and blindness symptoms can be diagnosed early and prevented with timely treatment.
Q: What is visual acuity?
A: Every eye has a different ability to separate the most miniature identifiable symbols, letters, details, or shapes. And there are measurements to check if one person can see clearly from a distance of 20 feet, known as visual acuity.
Q: What does this “20/20 vision” mean?
A: It means that if you can see clearly from a distance of 20 feet, your visual acuity is optimal and positively satisfying. Different sizes and letters won’t be challenging to read on a Snellen chart from a twenty feet distance or closer.
Q: Does this 20/20 vision mean faultless perception of things?
A: People who possess 20/20 vision see clearly, but they may not have the perfect eyesight. People may not have trouble reading certain information at a distance. But, they might experience night vision issues, contrast sensitivity, or other vision problems linked to presbyopia.
Q: What can cause drastic vision loss?
A: For individuals aged 40 or older, the significant causes of vision loss are cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy.
Q: What are cataracts?
A: Around 25 million Americans aged 40 or older have cataracts – a leading cause of vision loss. It can impair vision in those who don’t undergo cataract-removal surgery.
Q: What are the risk factors for cataracts?
A: Research suggests that the risk of cataracts can be increased by diabetes, prolonged exposure to sunlight, and smoking.
Q: What is diabetic retinopathy?
A: Diabetic retinopathy is the leading cause of blindness. It is caused by alternation in the retina blood vessels. To spot the condition early, an annual dilated eye exam is required. Many people with diabetes who seek to reduce the risk of diabetic retinopathy can try supplements marketed explicitly for the purpose.
Q: What is glaucoma?
A: Any damage to the optic nerve is called glaucoma. It is typically caused by inordinately high pressure in the eye. Many can easily prevent vision loss by detecting the condition early and resting it accordingly.
Q: What does the term age-related macular degeneration (AMD) mean?
A: It is an eye disease that blurs central vision. It affects up to 2 million Americans aged 50 or older. Age-related macular degeneration occurs when aging causes damage to the specific part of the eye retina that controls our sharp vision, or the macula. The light-sensitive tissue at the back of the eye that plays a crucial role in seeing is called the retina.
Q: What is hyperopia?
A: Also known as farsightedness, hyperopia is a condition in which one can see objects at a distance but cannot see things in their proximity.
Q: What is myopia?
A: Myopia is widely known as nearsightedness. In this common condition, people can clearly see the objects close to them but have difficulties perceiving some things in the distance. A greater rate of people is nearsighted than farsighted.
Q: How can eye exercises help in improving eye vision?
A: The neurological pathways between the eyes and the brain should be flawlessly connected. Therefore by strengthening it with the help of many simple exercises, the eyes can focus on improving various vision problems.
Q: Can exercises strengthen the eye muscles?
A: If necessary, orthoptics can strengthen eye muscles. But most eye therapy techniques do not involve strengthening the eye muscles.
Q: What food should I consume to maintain excellent vision?
A: A diet rich in fruits, vegetables, and lean protein is the best diet for healthy vision. The diet should also be low in saturated fats, and try to omit the salt, cholesterol, and all those added sugars as much as you can.
Q: How can vision supplements be effective?
A: Vision supplements consist of minerals, vitamins, amino acids, plant extras, and herbs linked to vision. Together, these contribute to better vision and more excellent eye health overall.
Q: How should I consume eye health supplements?
А: Most eye health supplements are taken as a pill or capsule. To support eye health, it’s best to take one or two tablets per day.
Q: What ingredients are stated to be the best for a vision supplement?
A: Vitamin A, vitamin B, vitamin C, vitamin E, zeaxanthin, lutein, omega-3 essential fatty acids, and more make the vital nutrients required for healthy eyesight.
Q: What makes the best vision supplement?
A: All ingredients above and formulas are a top priority for creating the best eye vision supplement. Please make sure you find the majority of them when choosing the best supplement for you.
Best Eye Vitamins for Vision Support Final Word
There are numerous ways to use supplements as a way to encourage good vision. Some work as antioxidants and help you see more clearly – like zeaxanthin and lutein. Others aim to support your eyes by targeting an individual cognition and maintaining overall brain health.
If you want to learn more about the most excellent vision supplements available momentarily and how they also act, look into some of the top-ranked vision supplements above.
RELATED: Vista Clear Reviews – Is VistaClear Supplement Legit? 2021 Updates
If you are interested in purchasing the product recommended at no additional value, this product review contains products that may result in small commission fees.
Please be aware that we only suggest high-quality products, and this small additional percentage goes towards the investigation and editorial team support.
Please consult a licensed physician before making any purchase, especially if you consume remedies or have concerns about the review details shared above. Make sure you understand that every guideline or advice published here is not even remotely a substitute for medical advice from an experienced healthcare provider. Individual results may vary since the Administration of Food and Drugs has not assessed the statements made regarding these vitamin pills. The efficiency of these supplements has not been approved by FDA research since these products are not intended to diagnose, heal, treat or stop any eyesight-related conditions.