How to Choose Artificial Tears: A Practical Guide to Eye Drops

Walk into any pharmacy and you will find a long row of eye drops promising relief for dry, tired or irritated eyes. Some are thin and watery, others thick and gel-like; some come in bottles, others in tiny single-use vials; some say preservative-free, others mention lipids, hyaluronate or carmellose. Choosing between them can feel confusing, and many people end up buying whatever is on offer.

Artificial tears (lubricating eye drops) are among the most widely used over-the-counter eye treatments and, used correctly, they can make a real difference to comfort. This guide explains the main types, how to match them to your symptoms, how often to use them, how to put drops in properly, which products to be cautious about, and when it is time to see an eye care professional.

What artificial tears do

The tear film is a thin, layered coating that keeps the surface of the eye moist, smooth and protected. It has a mucin layer that helps it stick to the eye, a watery (aqueous) layer, and an outer oily (lipid) layer that slows evaporation. When the tear film is insufficient or unstable, the surface of the eye becomes dry and irritated, causing symptoms such as burning, grittiness, redness, fluctuating vision and, paradoxically, sometimes watery eyes.

Artificial tears do not cure the underlying cause of dry eye, but they add moisture, lubricate the surface, dilute irritants and help the eyelids glide smoothly. For many people with mild dryness from screens, air conditioning, travel or contact lenses, they are all that is needed. For others, they are one part of a broader treatment plan. Our guide to dry eye disease explains the different types and causes.

The main types of artificial tears

Preserved versus preservative-free

Multi-dose bottles of eye drops need to stay sterile after opening, so many contain preservatives. The best known is benzalkonium chloride (BAK). With occasional use, preservatives are usually well tolerated. With frequent, long-term use, however, BAK can irritate and damage the cells on the surface of the eye, worsening the very dryness the drops are meant to treat.

Preservative-free drops avoid this problem. They come either in single-dose vials, which are discarded after use, or in special multi-dose bottles with filters or valves that keep the contents sterile. Some products use so-called disappearing or gentler preservatives that break down on contact with the eye; these are generally better tolerated than BAK.

As a rule of thumb, many eye care professionals recommend preservative-free drops if you use drops more than about four times a day, use several different eye drops, wear contact lenses, have sensitive eyes, or have moderate to severe dry eye.

Viscosity: thin drops, thicker drops and gels

Artificial tears differ in how thick (viscous) they are, depending on the lubricating ingredients they contain. Common ingredients include carboxymethylcellulose (carmellose), hydroxypropyl methylcellulose (hypromellose), sodium hyaluronate (hyaluronic acid), polyvinyl alcohol, povidone, glycerin, polyethylene glycol, propylene glycol and carbomers.

• Low-viscosity drops are watery and cause almost no blur, making them suitable for use during the day, at work and while driving. Their effect may be shorter, so you may need them more often.
• Medium-viscosity drops stay on the eye a little longer and suit many people with moderate symptoms.
• Gels are thicker and last longer, but they temporarily blur vision. They are useful for more persistent dryness and before bed.

Ointments

Eye ointments are greasy, usually based on paraffin or similar substances. They provide long-lasting lubrication and protection, but they blur vision considerably. For that reason, they are typically used at night, especially for people who wake with dry, painful eyes or whose eyelids do not close fully during sleep. They are not suitable while wearing contact lenses.

Lipid-based drops and sprays

Many people with dry eye actually have a problem with the oily layer of the tear film, often because of meibomian gland dysfunction or blepharitis. Their tears evaporate too quickly, a condition called evaporative dry eye. Lipid-containing drops, often milky emulsions, and liposomal sprays applied to closed eyelids aim to restore the oily layer and reduce evaporation. They can be a good choice if your eyes feel worse in wind, air conditioning or with screen use, and if you have crusty or red lid margins.

Other additives

Some products contain additional ingredients, such as osmoprotectants (for example trehalose), or electrolytes designed to mimic natural tears. Evidence comparing specific brands is limited, and no single product is best for everyone. A Cochrane review of over-the-counter artificial tears concluded that they may be safe and effective for relieving dry eye symptoms, but found little reliable evidence to separate different formulations.

How to choose: a simple approach

1. Start with a preservative-free, low to medium viscosity drop for daytime use if you have mild to moderate symptoms.
2. If relief is short-lived, try a more viscous drop or a gel, especially in the evening.
3. If your eyes feel worse in wind, air conditioning or at the screen, and your lid margins look red or crusty, consider a lipid-based product alongside eyelid care such as warm compresses.
4. If you wake with sore, dry eyes, an ointment or thick gel at bedtime may help.
5. If you wear contact lenses, choose drops specifically labelled as compatible with your lenses.
6. Give each product a fair trial of a week or two before deciding it does not work, as long as it does not cause irritation.

How often should you use artificial tears?

Artificial tears are generally safe to use as often as needed. Many people use them two to four times a day. With preservative-free products, more frequent use is acceptable. It often helps to use drops proactively before symptoms build up, for example before a long screen session, a flight or time in a dry environment.

If you find you need drops more than about six to eight times a day, or every hour, to stay comfortable, this is a sign that the dryness may need further assessment and other treatments. Our dry eye questionnaire can help you gauge how significant your symptoms are.

How to put in eye drops correctly

A surprising number of drops end up on the cheek rather than in the eye. A good technique makes treatment more effective and economical.

1. Wash your hands with soap and water.
2. Check the expiry date and, for bottles, how long the product can be used after opening.
3. Tilt your head back or lie down, and look up toward the ceiling.
4. Gently pull down the lower eyelid with one finger to create a small pocket.
5. Hold the bottle or vial above the eye without letting the tip touch the eye, lashes or fingers.
6. Squeeze gently to release one drop into the pocket. One drop is enough; the eye cannot hold more.
7. Close the eye gently for a minute or two. Do not blink hard or squeeze. Pressing lightly on the inner corner of the eye can help the drop stay on the eye.
8. Wipe away any excess with a clean tissue.
9. If using more than one type of drop, wait about five minutes between them, and apply gels or ointments last.

For more information about all kinds of eye drops, including prescription ones, see our guide on eye drops: types and correct use.

A warning about redness-relieving drops

Drops marketed to get the red out are not artificial tears. They usually contain vasoconstrictors, such as tetrahydrozoline, naphazoline or phenylephrine, which shrink the small blood vessels on the white of the eye to make it look whiter. They do not treat dryness or its cause.

With frequent or prolonged use, the blood vessels can dilate again as the effect wears off, often more than before, a phenomenon known as rebound redness. This can create a cycle of increasing use. These drops may also mask signs of a more serious problem, and some are unsuitable for people with certain types of glaucoma. If your eyes are often red, use lubricating drops instead and find out why. Our article on red eyes explains the possible causes.

Beyond drops: other ways to support your tears

Artificial tears work best alongside good habits. Take regular screen breaks with full blinks, keep the top of your screen at or slightly below eye level, avoid air blowing directly at your face, and consider a humidifier in dry environments. Our article on dry eyes in air-conditioned offices offers detailed workplace advice. Eyelid hygiene is helpful if you have blepharitis or meibomian gland dysfunction.

When to see a doctor

See an optometrist or ophthalmologist if your symptoms persist despite regular use of artificial tears for a few weeks, if you need drops many times a day, if your vision is blurred or fluctuating, or if dryness occurs with a dry mouth, joint pain or other general symptoms. An examination can identify the type and cause of dry eye and open up other treatments, such as prescription anti-inflammatory drops, treatment of the eyelid glands, or punctal plugs, which are decided by the doctor.