How to Make Isotonic Eye Drops at Home

Eye drops and eye baths are used when the eyes are inflamed (such as conjunctivitis or blepharitis) or simply tired or irritated.

Eye drops are the liquid used for eye baths. In general, the active ingredients are extracted from an infusion or decoction that has cooled (to body temperature), to which 0.9% salt has been added to make an isotonic solution.

You can apply eye drops, but for me, an eye bath (using a cup) is a much more comfortable option.

Why add salt to eye drops?

Adding salt to a solution that will come into contact with the delicate mucous membrane of the eyes may seem counter-intuitive: salt can appear abrasive to the eyes. But ocular fluid, like all cells in the human body, is made up of 0.9% salt. It’s important for eye drops to have the same percentage of salt, so as to be neutral and non-irritating to the body. If no salt is added, the salt in the eye fluid will try to balance the eye drops, causing irritation.

An isotonic solution, also known as physiological fluid, is made by adding 9 g of salt per liter of water.

As eye baths require little liquid, it is not necessary to prepare 1 liter. If you have a sufficiently accurate scale, you can use 0.9 g per 100 ml of infusion.

Storage of isotonic solutions and eye drops

Isotonic solutions are for single use only and cannot be stored.

Methodology of an eyewash

1. Sterilize the instruments you use. The easiest way is to place the containers, forceps and eye bath cup(s) in boiling water;
2. Make your own infusion or decoction; if you’re using my plant cards, I usually specify the correct dosages for external use in the use tab. Otherwise, you can make a concentration 3 to 5 times higher than for internal dosages;
3. Filter the infusion or decoction (use a fine filter to ensure that the solution contains no particles that would further irritate your eye);
4. Measure 100 ml and add 0.9 g salt;
5. Make sure the salt is dissolved and allow to cool (make sure you don’t contaminate your solution while it’s cooling) to room temperature;
6. Tilt the head to place the cup around the eye, close the eyelid, tilt the head back and open the eye for 15 to 30 seconds, then close and open again a few times. At the end, close the eye and tilt the head forward again, then remove the cup from the eye;
7. If treating both eyes, use a different sterilized cup for each eye, or re-sterilize the cup between each eye.

Tools

• One or two eyebath cups: it’s still possible to find eyebaths made of glass like in the old days, but you’ll find it easier to buy an inexpensive plastic cup that you can reuse in any good pharmacy. Ideally, you should buy two so you don’t have to re-sterilize when you want to treat both eyes;
• Pliers for handling sterilized cups;
• Two 200 ml glass containers (one for brewing and one for decanting the filtered infusion);
• A measuring cup;
• A scale that measures to the nearest 0.1 g (or even better, 0.01 g).

Ingredients

• Pure water (well filtered or, better still, osmosed);
• Salt;
• Selected medicinal plants.

The right plants for eye drops

Cornflower(Centaurea cyanus)#ref:6##ref:9##ref:41##ref:42##ref:66##ref:81##ref:107##ref:108#

It’s no coincidence that cornflower knapweed is also known as the eyeglass breaker. Centaury, which Europeans call cornflower, has been recommended for ophthalmic use in virtually all herbal works since Sainte-Hildedegarde. It’s a specialist plant that reduces irritation and inflammation while providing a small antimicrobial action, and can be included in virtually any eye drop preparation.

Part used: flower

Analgesic /Antipruritic	Anti-inflammatory/ Antioedematous	Antiseptic/ Antibacterial	Astringent	Emollient
	⭐⭐⭐	⭐	⭐⭐	⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion, hydrolat	yes	cream, cosmetic product

Euphrasia(Euphrasia officinalis subsp. rostkoviana)#ref:9##ref:15##ref:44##ref:107#

Another great eye specialist (it’s also often referred to as a eyeglass breaker). Euphrasia is more astringent than knapweed and very effective against inflammation. However, it should be avoided in cases of dry eye.

Part used: flower

Analgesic / Antipruritic	Anti-inflammatory/ Antioedematous	Antiseptic/ Antibacterial	Astringent	Emollient
⭐	⭐⭐	⭐	⭐⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	yes	yes

Plantain(Plantago lanceolata or Plantago major)#ref:9##ref:15##ref:66##ref:107##ref:108#

Plantain is so well known for soothing itchy bites and blisters on the feet that we often forget that it’s also an excellent plant for coughs, but also for the eyes. This plant is frequently used in eye drops. It softens the mucous membrane while treating inflammation. Plantain is particularly recommended if inflammation is allergic in origin, or as a preventive measure against conjunctivitis and blepharitis.

Part used: leaf

Analgesic / Antipruritic	Anti-inflammatory/ Antioedematous	Antiseptic/ Antibacterial	Astringent	Emollient
⭐⭐⭐	⭐⭐	⭐⭐	⭐⭐	⭐⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
yes	yes	infusion	yes	ointment

Sweet clover(Melilotus officinalis)#ref:9##ref:66##ref:107##ref:108#

This plant is used against eye irritation . By increasing venous and lymphatic flow, it is a powerful anti-oedematous that is gentle on the eye.

Part used: flowering tops

Analgesic / Antipruritic	Anti-inflammatory/ Antioedematous	Antiseptic/ Antibacterial	Astringent	Emollient
⭐	⭐⭐⭐	⭐		⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion	yes	cream, cosmetic product

Rose(Rosa spp.)#ref:9##ref:107##ref:113#

Rose, with its gentle astringency that gives it its anti-inflammatory properties, is also highly appreciated for eye baths.

Part used: petal

Analgesic / Antipruritic	Anti-inflammatory	Antiseptic/ Antibacterial	Astringent	Emollient
	⭐⭐		⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion, hydrolat	yes	cream, cosmetic product

German chamomile(Matricaria recutita)#ref:9##ref:44##ref:66# and Roman chamomile(Chamaemelum nobilea)#ref:20##ref:107##ref:108#

Chamomile either german or englsh are both great anti-inflammatories. These plants will play a key role in calming irritation, and German chamomile may even help fight infection. It’s true that their small flowerheads are reminiscent of the eyes, which explains why they are relatively often cited for eye drops, even though they are not, in my opinion, great eye specialists.

Part used: flower head

Plant	Analgesic / Antipruritic	Anti-inflammatory	Antiseptic/ Antibacterial	Astringent	Emollient
German chamomile	⭐⭐	⭐⭐⭐	⭐⭐	⭐⭐	⭐⭐
Roman chamomile	⭐⭐	⭐⭐			⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion, hydrolat	yes	cream, cosmetic product

Marigold(Calendula officinalis)#ref:15##ref:20#

We think less often of calendula; perhaps we’re too dazzled by its bright yellow color. Yet with its antiseptic, emollient, analgesic and anti-inflammatory qualities, it has everything we need to care for our eyes. In my opinion, this flower is under-utilized for eye care, especially if the problem has a microbial origin.

Part used: flower

Analgesic / Antipruritic	Anti-inflammatory	Antiseptic/ Antibacterial	Astringent	Emollient
⭐⭐	⭐⭐	⭐⭐⭐	⭐⭐	⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion	yes	cream, cosmetic product

Witch hazel(Hamamelis virginiana)#ref:20##ref:66#

This plant is often added to eye baths to reduce swelling and pain. You wll also fnd witch hazel’s hydrosol used in cosmetics around the eyes.

Part used: leaf

Analgesic / Antipruritic	Anti-inflammatory	Antiseptic/ Antibacterial	Astringent	Emollient
⭐⭐	⭐⭐		⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion, hydrolat	yes	cream, cosmetic product

Mallow(Malva spp.)#ref:9##ref:66#

Finally, mallow is always welcome with its emolliency, to soften mucous membranes. It’s not a specialist, but it’s very useful for dry eyes.

Part used: flower

Analgesic / Antipruritic	Anti-inflammatory	Antiseptic/ Antibacterial	Astringent	Emollient
⭐⭐	⭐⭐			⭐⭐

Cataplasm	Eye drops	Compress	Internal	Other
	yes	infusion	yes	cream, cosmetic product

For your own good …

Read the plant sheet

As far as possible, I try to offer a hyperlink for each plant proposed. This link opens a plant fact sheet which not only gives information about the crop, but, if you look at the uses, also information for safe use of the plant (methods of use, safe doses, precautions, interactions, properties). Naturally, if you have a complicated medical condition, this sheet won’t be enough and you’ll need to consult a professional herbalist or pharmacist. But even if you’re in good health, for your own safety, take the time to get to know the plants before using them. They are natural, but also powerful.

A few differences

Swelling and inflammation

Edema is swelling due to an accumulation of fluid, while inflammation is an immune system response that includes edema, but also heat, redness and pain.

Antiseptic and antibacterial

An antiseptic is used externally and prevents all microbes (bacteria, fungi, viruses and other micro-organisms), whereas an antibacterial or antibiotic acts only against bacteria, but can be used both internally and externally.

The issues addressed

Issues: Conjunctivitis and blepharitis

As conjunctivitis is inflammation of the conjunctiva, and blepharitis of the eyelid, anti-inflammatory plants are the first to look for, along with plants with the following properties:
– Antibacterial, antiseptic or antiviral: combat the cause if it’s linked to a micro-organism;
– Analgesic, antipruritic: reduce discomfort caused by irritation and inflammation of mucous membranes;
– Astringent: tightens mucous membranes and reduces inflammation, but should be avoided if eyes are dry;
– Emollients: soften mucous membranes caused by irritants (cold wind, smoke, dust, chemicals, foreign bodies).

Internal : goldenseal(Hydrastis canadensis), echinacea(Echinacea spp.)
Externally (eye baths, compresses and poultices): calendula(Calendula officinalis), German chamomile(Matricaria recutita), Roman chamomile(Chamaemelum nobilea), cornflower(Centaurea cyanus), witch hazel(Hamamelis virginiana), mallow(Malva spp.), plantain(Plantago lanceolata or Plantago major) and rose(Rosa spp.).

Photo credit: Joyhill09

Issue: Stye

As a stye is an infection of the pilosebaceous follicle, antibacterial (especially if caused by staphylococcus aureus) and antiseptic herbs are preferred:

– Anti-inflammatory and astringent: tighten mucous membranes and reduce inflammation;
– Analgesic, antipruritic: reduce discomfort caused by irritation and inflammation of mucous membranes;
– Immunostimulants: help fight infection.

Internal : goldenseal(Hydrastis canadensis), echinacea(Echinacea spp.).
External: (compress, poultice, ointment): goldenseal(Hydrastis canadensis), calendula(Calendula officinalis), potato(Solanum tuberosum).

Photo credit: Andre Riemann

Alternative methods

Eye drops, compresses and poultices

Drop-by-drop

Drop-by-drop involves putting eye drops (the same solution used for eyewash) directly into the eye. I personally believe that this technique tends to spread the eye drops around the eye rather than on the cornea and eyelid. What’s more, with homemade preparations, whether you use eye drops or eye baths, the preparation cannot be preserved and is for single use only.

Compress and poultice

The compress uses an infusion or decoction of the plant, cooled to room temperature, to soak a cotton pad or flannel.

The poultice is a paste made from the plant (sometimes also clay); other herbal infusions or liquid preparations can be added.

Some active plant ingredients pass through the skin to play a very interesting active role. One need only think of the somewhat cartoonish image of cucumber pieces on the eyes to understand just how much a compress can relieve and refresh irritated eyes. For both compresses and poultices, hold them in place over closed eyes for 10 to 15 minutes. The treatment can be repeated several times a day.

Goldenseal, with its berberine, is very effective for staphylococcal infections such as styes; as goldenseal is strongly astringent, it would be irritating in eye drops, but very useful as a compress or taken internally.

Photo credit:

• Centaury: Bdk
• Euphraise: Tigerente
• Plantain: Forest and Kim Starr
• German chamomile: Mauricio Mercadante