General Description
Eyebright is an annual herb common in grassy areas throughout much
of Europe, western Asia, and the subarctic regions of North America.
Reaching up to 20 centimeters in height, eyebright has stiff, ovate
leaves, which are roughly 13 mm long and 8 mm wide, positioned opposite
at the base of the plant and alternate toward the top. The plant
is hemiparasitic; the roots have nodules that attach to the roots
of other plants to obtain nutrients.1 Eyebright
flowers from June to September, producing white or pale purple,
two-lipped blossoms, which are often marked with purple and yellow
spots and stripes. The fruit of the plant consists of small, flattened
capsules, which contain numerous ribbed seeds.
Health Applications
History and Traditional Use
Eyebright, as its name suggests, has traditionally been used as
an eye tonic. Although it is unknown when this use started, eyebright
was well established as an eye medicine by the 14th century.2
In his epic poem Paradise Lost, Milton describes how the Archangel
Michael used eyebright to restore Adam's sight after the eviction
from Eden. The famous 17th century British herbalist Nicholas
Culpeper recommended both internal and external applications of
eyebright for "all infirmities of the eyes that cause dimness
of sight."3 Many modern herbalists recommend
an infusion of the above-ground portion of the plant, used as
an eyewash, for various eye and sinus ailments. The herb is often
taken internally for the same purposes. There are no modern studies
demonstrating the effectiveness of eyebright for any of these
traditional uses.
Chemical Composition
Chemical studies of eyebright have identified several constituents,
including aucubin, caffeic acid, ferulic acid, sterols, choline,
and a volitile oil.1 However, no therapeutic
activity for any of these compounds has been demonstrated in scientific
studies.
Dosage/Toxicity
For an eyewash or tea, a common recommendation is 28 grams of
the herb steeped in 500 ml of boiling water.4
The dried herb is also available in capsules, for which the usual
dosage ranges from 800 to 1400 mg per day. While the tea can be
consumed liberally with no adverse effects, out of concern for
harmful impurities, Gemany's Commission E (the German government's
expert panel on herbal remedies) does not recommend external application
of eyebright infusions to the eyes.5 |
