EYEBRIGHT

BACKGROUND

Ingredient Type: Botanical, Herb

Also Known As: Euphrasia officinalis, Eyebright euphrasia, Euphrasia, Aufraise, Casse-Lunettes, Euphrasiae herba, Luminet, Eyebright grass, Eye bright

Eyebright is a flowering plant that grows naturally in the grassy pastures and meadows of Britain, Europe, North America, and northern and western Asia.  It’s a semi-parasitic plant, meaning that it uses the roots of nearby plants to obtain its nourishment, and is, consequently, difficult to cultivate if transplanted from the wild (1).  Euphrasia, the Latin name for eyebright, comes from the Greek word euphrosyne, which means gladness.  The name likely originated based on the belief that the plant could be used to preserve the eyesight of those with eye problems, thereby bringing them gladness (2,3).

TRADITIONAL USES

Some authors familiar with the history of eyebright claim that it has been used medicinally since the 14th century.  One of the first written mentions of the medicinal use of eyebright, however, is in a German book on herbs from 1485.  From this record, we know that eyebright was used in medicine to treat ailments of the eye.  Other records from the middle ages indicate that the plant was believed to be able to cure “all evils of the eye.”  This belief is what likely gave rise to the herb’s current common name (4).  Although the main use of eyebright throughout history was to treat the eyes, it was also used to help memory problems and coughs.  Eyebright ale was common in the late 1500s, during which time the plant was also dried and smoked in combination with tobacco to help improve bronchial colds (1,2,5).

Today, eyebright is made into an aqueous extract that is used to treat many conditions.  Compounds in the plant are believed to have properties that help fight inflammation, pathogenic bacteria, fungi, viruses, and cancer.  It is also thought to be an antioxidant, hypotensive, anti-epileptic, and anti-catarrhal supplement (6).  The modern uses of eyebright still mainly consist of treating eye disorders, like conjunctivitis (“pink eye”), ulcers of the eye, weak vision and eye strain, as well as itching, burning, red or weeping eyes.  It is occasionally also used for treating coughs, allergy symptoms, hay fever, sinusitis, jaundice, headaches, earaches, flu, and throat congestion (1).

Without question, the most consistent traditional medicinal use for eyebright has been:

• To treat ailments of the eye

WHAT DOES SCIENCE TELL US?

Eyebright Possibly Helps the Eyes:

There is very little clinical research supporting the positive benefits of eyebright for eye conditions.  The one prospective cohort study that has been conducted shows some potentially beneficial effects.  This particular study examined the effects of eyebright drops administered directly into the eye on typical conjunctivitis symptoms such as redness, swelling, burning, and blurred vision.  In this study, 65 patients with inflammatory or catarrhal conjunctivitis were prescribed eyebright drops that were to be used 1-5 times daily for up to 14 days.  The researchers reported that 81.5% of study participants experienced a complete recovery, while a significant improvement was seen in another 17.0% of participants, only 1 participant showed a slight worsening of symptoms.  Four of the study participants experienced mild adverse effects, but the authors of the study suggested that this may have been due to the normal course of conjunctivitis and not to the eyedrops themselves.  It should be noted, however, that the eyebright drops used in this study actually contained Euphrasia (species not specified) and Rosae aetheroleum.  Caution should be taken in assuming the efficacy of a single ingredient from the effect of a mixed ingredient product.  The study was also an open cohort study and, as such, contained no placebo comparison or double-blinding.  Whether eyebright drops are more effective than placebo in relieving the symptoms of conjunctivitis is yet to be determined (7).

An in vitro study used cultured corneal epithelial cells of humans to test the effects of eyebright extract.  Results suggest that the extracts are safe to use on the human eye, even in high concentrations (125 µg/mL).  It was also discovered that eyebright extract lowered pro-inflammatory markers, although it also lowered anti-inflammatory markers as well (6).  Results from in vitro studies do not, however, always translate to live humans; and safety and efficacy of natural ingredients should never be assumed based on in vitro studies alone.

Ongoing research is being conducted to assess the use of eyebright eye drops to treat narrow-angle glaucoma in patients following a peripheral Laser Iridotomy surgery.  This double-blind, randomized trial is currently being conducted and will assess the efficacy of the supplement in comparison to commonly prescribed steroid drops.  The main outcome measure will be inflammation of the eye (8).

Evidence is Lacking for the use of Eyebright for Other Purposes:

There are currently no clinical trials investigating other benefits of eyebright in humans.  One study conducted on rats, however, revealed that eyebright extract was effective in reducing blood glucose levels in the rats with induced diabetes.  Eyebright was found to be ineffective for lowering blood glucose in healthy rats (9).  It is important to note that, as with in vitro studies, the results of animal studies do not always translate to humans.  The safety and efficacy of natural ingredients should never be assumed based on animal studies alone.

SAFETY

There is scarce evidence to determine whether eyebright is safe for human use.  However, of the few studies conducted concerning the benefits of eyebright drops on human health, none reported any serious adverse or toxic effects (6,7).  The Natural Medicines Comprehensive database concludes that eyebright is possibly safe when used orally and appropriately, but warns that it is possibly unsafe when used as an ophthalmic due to hygienic concerns (10).  Ultimately, there has not been enough clinical research to adequately support the safety of eyebright supplementation (11).

Interactions:

No identified interactions.

Side-Effects:

There is a lack of research on the side effects of eyebright. Some side effects may include:

• Eye redness, swelling, burning, blurred vision, and eye secretions (7).
• Headache, itching, confusion, sensitivity to light, weakness, eye pressure, and sneezing (12).

REFERENCES

1. Eyebright. Gale Encyclopedia of Alternative Medicine. https://www.encyclopedia.com/plants-and-animals/plants/plants/eyebright#1G23435100299. Accessed March 22, 2018.
2. Committee on herbal medicinal products. Assessment report on Euphrasia officinalis L.and Euphrasia rostkoviana Hayne, herba. European Medicines Agency. 2010.
3. Grieve M. A modern herbal. Dover Publications Inc. 1971 republication of a 1931 original work.
4. Bone K and Mills S. Principles and practice of phytotherapy: modern herbal medicine. Churchill Livingstone. 2013.
5. Harkiss KJ and Timmins P. Studies in the Scrophulariaceae part VIII phytochemical investigation of Euphrasia officinalis. Planta Med. 1973;23(2):182-190. doi:10.1055/s-0028-1099431.
6. Paduch R, Woźniak A, Niedziela P, Rejdak R. Assessment of eyebright (Euphrasia officinalis L.) extract activity in relation to human corneal cells using in vitro tests. Balkan Med J. 2014;31(1):29-36. doi:10.5152/balkanmedj.2014.8377.
7. Stoss M, Michels C, Peter E, Beutke R, Corter RW. Prospective cohort trial of Euphrasia single-dose eye drops in conjunctivitis. J Altern Complement Med. 2000;6(6):499-508. doi:10.1089/acm.2000.6.499
8. Use of topical Euphrasia, a homeopathic remedy in ophthalmology. ClinicalTrials.gov. 2015. https://clinicaltrials.gov/ct2/show/NCT02416128.
9. Porchezhian E, Ansari S., Shreedharan NK. Antihyperglycemic activity of Euphrasia officinale leaves. Fitoterapia. 2000;71(5):522-526. doi:10.1016/S0367-326X(00)00204-5.
10. Eyebright. Natural Medicines Comprehensive Database. 2015 last reviewed 2018. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?pt=100&id=109&ds=&name=EYEBRIGHT&searchid=63605748&cs=&s=ND. Accessed April 19, 2018.
11. European Medicines Agency. Assessment report on Euphrasia officinalis L. and Euphrasia rostkoviana Hayne, herba. 2010. http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_HMPC_assessment_report/2011/01/WC500100385.pdf. Accessed March 28, 2018.
12. Fetrow CW and Avila JR. The Complete Guide To Herbal Medicines. New York: Pocket Books. 2000. https://books.google.com/books?id=5INyROQ9vHoC&pg=PA201&dq=side+effects+of+eyebright&hl=en&sa=X&ved=0ahUKEwiwqumJppDaAhWOzlMKHZj-AjgQ6AEIJjAA#v=onepage&q=side effects of eyebright&f=false. Accessed March 28, 2018.

See the WebMD entry for eyebright, the Michigan Medicine Health Library entry for eyebright, this European Medicines Agency monograph on Euphrasia officinalis & rostkoviana, or the RXList entry for eyebright for more information.