Eye drops come in many different shapes and forms. Some are over the counter, others are prescription strength. They have different uses, dosages, colors, consistencies, and more. As such, the question “what is in eye drops?” is a very difficult one to answer, as it all depends on the product. The following does explain a few things to look for that will tell you what could be in your eye drops.
What Are Eye Drops
Eye drops almost always have saline, where sterile water is the main ingredient. They may also contain medications, preservatives, anti-redness agents, tear-replacing ingredients, and lubrication. Because your eyes are such delicate organs, you have to look after them properly and make sure that if you do have to use eye drops, you are using the right ones, in the right way.
Types of Eye Drops, Usage, and Ingredients
The table below highlights some of the common eye conditions that are treated with eye drops, and which drops are generally used.
|Eye Condition||Details||Types of Drops|
|Cataract surgery||Your natural lens is removed and replaced with an artificial one. Eye drops are given before the surgery to numb the eye, enlarge the pupil, and prevent infection. Eye drops are also prescribed after surgery to encourage healing and lower the risk of infection.||· Antibiotic eye drops
· Anti-inflammatory drops
|Conjunctivitis||Also known as pink eye, this is an infection of the cornea. The infection can be bacterial or viral. Or the condition may be an allergic reaction.||· Antihistamine drugs
· Antiviral drugs
· Antibiotic drugs
|Dry contact lenses||People who wear contact lenses often find their eyes become dry, turning to eye drops to make the eye more comfortable.||Rewetting drops|
|Corneal infections||Also known as keratitis, this can be bacterial, viral, or parasitic. Eye drops are usually prescribed to help treat keratitis.||· Rewetting drops
· Anti-inflammatory drops
· Antibiotic drops
· Antiviral drops
· Anti-parasitic drops
|Corneal transplant surgery||In this case, a damaged part of the cornea is replaced using one from a donor. Drops are prescribed to help prevent tissue rejection.||Steroid eye drops|
|Dry Eye Syndrome (DES)||This is a chronic, uncomfortable condition caused by insufficient tear production, or poor quality tears (or both). Artificial tears, usually available over the counter, can help to alleviate the symptoms.||Artificial tears|
|Allergies||Allergies are very common, particularly during certain seasons. Different drops can be prescribed, depending on the severity of the allergic reaction.||· Antihistamine drugs
· Artificial tears
|Eye examination||During eye examination, different types of drops may be administered to allow the optician to properly investigate the eye. These include numbing drops, dyes, and drops to dilate the pupil.||· Eye numbing drops
· Dye drops
|Glaucoma||Glaucoma is a very serious condition in which pressure builds up behind the eye. This can lead to permanent nerve damage and vision loss. Early glaucoma is generally treated with pressure-relieving drops.||Pressure lowering (anti-glaucoma) drops (research shows that using this preventatively lowers the chance of developing glaucoma by 50%)|
|Herpes Simplex||This is a viral infection that can affect the eye, eyelid, and cornea.||Antiviral drops|
|LASIK||LASIK eye surgery is designed to correct vision problems for which otherwise lenses or glasses would be needed. Drops are applied before the surgery to numb the eye, and after the surgery to encourage healing.||Anesthetizing drops|
The table below highlights the common ingredients found in the types of eye drops mentioned above.
|Type of Eye Drop||Common Ingredients|
|Anti-inflammatory drops||Nonsteroidal anti-inflammatory drugs, corticosteroids|
|Antihistamine drops||Emedastine difumarate, levocabastine, azelastine hydrochloride|
|Artificial tears||Hydroxypropyl methylcellulose (ophthalmic) or carboxymethylcellulose|
|Rewetting drops||Boric acid, poloxamine, sodium borate, and sodium chloride;preserved with sorbic acid (0.15%) and edetate disodium (0.1%)|
|Eye numbing drops||Teltracaine|
|Dye drops||Fluorescent dye|
|Anti-glaucoma drops||Prostaglandins, beta-blockers, alpha-adrenergic agonists, carbonic anhydrase inhibitors|
The list above shows the huge variety of different eye drops that exist. Most of these eye drops are created by a range of different manufacturers, each of which uses different ingredients. Because the majority are prescription eye drops, your physician will be best placed to find the one that is right for you. However, there are also many over the counter eye drops that you can purchase, each of which has different ingredients and different workings, although some will claim to do the same thing. The table below highlights this in some greater detail.
|Type of Eye Drop||Uses||Ingredients|
|Lubricating eye drops||Supplement natural tears, making them more efficient at keeping the eye moist and comfortable. Helps to relieve dry eyes.||Polyethylene glycol|
|Decongestant eye drops||Suitable if your eye discomfort is caused by a cold or flu, or other type of congestion. Helps to relieve red eyes.||Flurbiprofen sodium|
|Antihistamine eye drops||Designed to help relieve irritation caused by allergies.||Emedastine difumarate, levocabastine, azelastine hydrochloride|
|Preservative free eye drops||Generally used for any eye condition. Suitable for more longer term or frequent use, as it does not contain preservatives.||Saline|
|Rewetting drops||Designed for people with contact lenses.||Boric acid, poloxamine, sodium borate, and sodium chloride;preserved with sorbic
acid (0.15%) and edetate disodium (0.1%)
Do’s and Don’ts
Whatever it is that you want, or need, to use eye drops for, it is important that you use them properly. While they are more commonly found in a medicine cabinet than aspirin or paracetamol, most people don’t really know that there are some dangers associated with these drops. The rule of thumb is that more does not necessarily mean better. Rather, it is about using the right technique so that each drop counts. As such:
- Apply one drop at a time. Research by the American Academy of Ophthalmology has shown that people often apply lots of drops at one time. However, an eye cannot hold more than one drop at a time, which means that any further drops are being wasted, as they will roll down your eyes. Instructions may say that multiple drops must be applied, but this references a specific time period, not all at the same time. Not only does applying too many drops cost money, as you will waste them, it also means that you could damage your eyes to a degree.
- Don’t mix different eye drops at the same time. There are situations, for instance if you are at risk of glaucoma, have had cataract surgery, or have just had LASIK completed, that you will need different drops. It is vital that you leave at least 30 minutes between each drop. This is firstly to give each drop the chance to actually do its work. Secondly, it stops the drops from interacting with each other, which often causes irritation and burning. If you do have to take multiple drops, a medical professional should tell you which one to take when.
- Make sure to check your dosage. A lot of people make the mistake of thinking over the counter medication are completely harmless. As such, they will often apply eye drops almost continuously. Different drops have different ingredients that you eye should only be exposed to so many times. You must, therefore, use the correct dosage. If you are allowed to use the drops quite often during the day, you should write down each time you use them, so you don’t accidentally use too much.
- Never skip drops, particularly with prescription drugs. A lot of people who are prescribed drops will not use them on a day where they have to go in for an examination, believing the examination will not paint a true picture. This is not true. If you have been prescribed drops, you should use them as directed and your physician will be aware of this.
- Watch that expiration date. Because most over the counter drops are based on saline, which is basically sterile water, people often think that their drops cannot expire. This is not true, however, and the vast majority of drops contain ingredients other than saline as well. Even saline will lose its sterility after a period of time.
- Put the drops in the right way. Your product should come with full instructions on how to apply the drops. Usually, however, you simply have to tip your head back and pull your lower eyelid down, before applying a single drop while you look up and away. After that, you generally have to close your eyes for a few minutes without rubbing them, squinting or blinking.
- Take out your contacts. Too many people use eye drops and contacts at the same time. Almost every case of eye problem is caused by a bacterial or viral infection, and these bacteria and viruses remain on the contact lenses. As soon as you start to develop a problem with your eyes, you should remove your contacts and dispose of them. Don’t put them back in until your eye problem has been resolved.
A Word of Caution
Because there are so many eye drops available as over the counter remedies, it is all too easy to self-medicate. However, many symptoms that are common with chronic conditions like dry eye, or that can appear as part of allergy or a simple cold, can also be indicative of a more serious problem. Furthermore, all eye drop ingredients, whether over the counter or not, have the potential to have drug interactions with any other products you are taking, prescription or not. It is vital, if you have a problem with your eyes, that you speak to a specialist and receive a recommendation in terms of which drops to use. If you are currently taking any medication, you must speak to a pharmacist about whether or not there is a possible interaction. Last but not least, even over the counter remedies can have side effects. This is why you should always read the product insert, which will explain what you can expect, and seek medical attention if you notice any of the more serious side effects, or if you experience a side effect not listed.
Resources and References:
Eyedrops Used After Cataract Surgery – Information on eye drops for use after cataract surgery. (American Academy of Ophthalmology)
Corticosteroid Eye Drops Used in Addition to Standard Antibiotic Therapy in the Treatment of Bacterial Keratitis – Eye drops used as part of treatment for bacterial keratitis. (PubMed Health)
About Corneal Transplant Surgery – Information on corneal transplants. (National Keratoconus Foundation)
Teltracaine (Ophthalmic Drops) – Information on teltracaine eye drops. (Medicine Net)