Also known as Euphrasia officinalis.
Eyebright is the only British species of a genus containing twenty species distributed over Europe, Northern and Western Asia and North America. It is a small, elegant plant, with stems about 2 - 8 inches high, which grows on heaths and other dry pastures, especially on a chalky soil.
The stem is erect and wiry, either unbranched in small plants, or with many opposite branches. The leaves are small and grow opposite to one another on the lower portion of the stem, and alternate above.
Eyebright has numerous small white or purplish flowers, variegated with yellow, which appear from July to September. The structure of the flowers places the plant in the family of the Foxglove and the Speedwell - Scrophulariaceae. They somewhat resemble a bloodshot eye, which may have been part of what led ancient people to value this plant for eye problems. The corolla’s lower, tube-like portion is enclosed in a green calyx, tipped with four teeth. The upper lip is two-lobed and arches over the stamens, forming a shelter from the rain. A yellow patch emphasizes the central lobe and purple 'honey guides' - marked streaks of colour - point the way down the throat. Four stamens, with brown, downy anthers lie under the upper lip. When a bee comes in search of the honey lying at the bottom of the petal tube, it knocks against the projecting anther spurs, which sets the pollen free so that it falls on the insect's head. On visiting the next flower, the bee will then rub this pollen against the outstanding stigma, and thus cross-fertilisation is effected. The seeds in all kinds of the flowers are produced in tiny, flattened capsules, and are numerous and ribbed.
Eyebright will not grow readily if transplanted, unless 'protected' by plants, the reason being that it is a semi-parasite, relying for part of its nourishment on the roots of other plants. It is best collected in July and August, when in full flower and the foliage is in the best condition.
Eyebright is high in iridoid glycosides, flavonoids, and tannins, and also contains mannite and glucose. It is rich in vitamins A and C.
The genus name, Euphrasia, is derived from the Greek Euphrosyne, who was one of the goddesses of the Three Fates, and whose name means ‘gladness’. It is thought to have been given to the plant because of the valuable properties attributed to it as an eye medicine, and refers to the gladness felt when a person’s vision was improved from using the herb.
In the fourteenth century, it was said to cure 'all evils of the eye' and is described as the source of 'a precious water to clear a man's sight'. In Gordon's Liticium Medicina (1305), ‘Euphragia’ is named among the medicines for the eyes, and is ‘recommended both outwardly in a compound distilled water, and inwardly as a syrup.' In the eighteenth century, eyebright tea was used, and in Queen Elizabeth's era an 'Eyebright Ale' existed. It was also used primarily in the Middle Ages as a tonic because of its astringent properties.
In modern medicine, eyebright is used more frequently for relieving eye problems such as eyestrain, and inflamed, irritated, and sore eyes. The plant’s astringent properties and tannin content probably account for its usefulness as a topical treatment for inflammation, and the antibiotic and astringent properties tighten membranes surrounding the eyes, effectively strengthening and improving circulation.
Astringent properties found in Eyebright also make it ideal for relieving excess mucus and infectious conditions generally associated with sinusitis allergies, colds and upper respiratory problems. It has recently been used for cleansing and purifying the blood, therefore stimulating healthy liver functions.
The dried herb is an ingredient in British Herbal Tobacco, which is smoked most usefully for chronic bronchial colds.