Several herbal medications have been linked to clinically significant ocular side effects, says a study in the October American Journal of Ophthalmology. The study chose to highlight the following because of the frequency of reporting, the available literature and pertinence to eye care:

Canthaxanthine has been found to cause visual changes, including abnormalities in static threshold perimetry, electroretinography and adaptation to darkness.

Chamomile may cause severe conjunctivitis when used in or around the eye. (Some have used the herb to treat styes and runny, irritated eyes.) It is also used to treat fevers, bronchitis, insomnia, indigestion, migraine headaches, inflammation, burns and colds.

Datura was discovered to cause mydriasis and dilated pupils. It is used to treat bronchitis, coughs, influenza, asthma and eye inflammation.

Echinacea purpurea can cause eye irritation and conjunctivitis secondary to topical use. It is used to treat the common cold, urinary tract infections, coughs, burns, flu and fevers.

Ginko biloba can cause spontaneous hyphema and retinal hemorrhages. It has been prescribed for dementia, equilibrium disorders, peripheral occlusive arterial disease, asthma, tinnitus, hypertonia, angina pectoris and tonsillitis.

Licorice was found to cause pseudoaldosteronism and transient visual loss after ingestion, and it may exacerbate migraine headaches in those who have such a history. This herb has been used to treat upper respiratory tract infections, constipation, appendicitis, hepatitis C, gastric ulcers and peptic ulcers. 

Niacin was associated with discoloration of the eye lids, decreased vision, dry eyes, cystoid macular edema, loss of eyebrows and eyelashes, proptosis, eyelid edema and superficial punctate keratitis. It has been used for cerebrovascular and cardiovascular disease, schizophrenia, arthritis, hypertension, diabetes, sexual dysfunction and migraine headaches.

Alternative forms of Vitamin A (retinol), such as tretinoin, isotretinoin, etretinate and acitretin have been shown to cause intracranial hypertension. They are used for severe recalcitrant nodular acne, severe recalcitrant psoriasis, acne vulgaris and to induce leukemia remission.

 The study was based on spontaneous case reports that were submitted to the U.S. Food and Drug Administration, the World Health Organization (WHO) and the National Registry of Drug-Induced Ocular Side Effects. The study included 263 spontaneous reports in addition to 60 reports from the literature.

Fraunfelder FW. Ocular side effects from herbal medicines and nutritional supplements. Am J Ophthalmol 2004 Oct;138(4):639-47.