therapeutic topics

Ocular Side Effects of Herbal Supplements

therapeutic topics
Ocular Side Effects of Herbal Supplements

An often overlooked area of patient history is patient use of herbal or natural supplements on either an acute or chronic basis. Practitioners frequently disregard supplements' potential to cause ocular side effects because of their "natural" moniker.

Herbal and natural supplements are an estimated $5 billion industry this year. Studies indicate that between 40 percent and 60 percent of patients admit to using an herbal or natural supplement in the previous year. Additionally, a 1993 study that appeared in the New England Journal of Medicine found that 70 percent of patients do not report using herbal and natural supplements when doctors ask questions about routine drug and over-the-counter medications. These statistics show that practitioners need to ask patients about herbal and natural supplements to obtain a complete patient history.

Dosing Differences

Patients who take herbal and natural supplements may use variable dosages and modes of administration. Although recommendations for dosages exist, they can represent a range of extremes. Some patients may think, "if a little is good, then a lot is even better." Patients who take supplements at higher dosages and frequencies are more likely to experience side effects.

What does this mean to contact lens practitioners?

Supplements to Watch for

Some herbal and natural supplements can cause side effects and reactions that can compromise contact lens wear. Garlic is a common supplement that has antilipidemic, antimicrobial, anti-asth matic and anti-inflammatory properties. Systemic dissipation of the aromatic oil upon ingestion of high doses may cause increased tearing and minor ocular irritation in some patients. These aromatic oils can contaminate contact lenses and prolong the tearing and irritation.

Ephedra (ma huang, Mormon tea, popotillo, sea grape, yellow horse, epitonin) is a common and controversial supplement available in a variety of preparations. It can be a strong central nervous system stimulant. Traditionally, doctors used Ephedra to treat asthma, bronchitis, headache and inflammation. Most recently it has served as an additive to increase energy and boost weight loss. Its stimulant and amphetamine-like properties result in pupillary mydriasis.

Pupil dilation can cause new or increased complaints of flare and glare in rigid contact lens wearers. Visual performance is compromised if the pupil dilates beyond the optic zone of the rigid lens and expands into the lens's peripheral curves. Patients who wear soft and rigid bifocal contact lenses with pupil-dependent designs will also experience performance alterations with any mydriatic effect. Certain formulations of Ephedra also reportedly cause contact lens discoloration.

Use of the supplement Eyebright dates back to the 14th century. It reportedly alleviates conjunctivitis, blepharitis, styes, hay fever and eye fatigue. Patients can use Eyebright as a wash, soak, drop or tea.

Hypersensitivity reactions are not uncommon with Eyebright. If a patient experiences such side effects, he should discontinue its use and begin antihistamine therapy. Other possible side effects include blurred vision, photophobia and lid swelling. Patients should not use Eyebright during contact lens wear because of its documented cytotoxic effects.

More to Keep an Eye on

Next month's column will highlight additional examples of herbal and natural supplements whose side effects can affect contact lens wearers.

Dr. Schornack is the Assistant Dean of Clinical Education and serves in the Cornea and Contact Lens Service at the Southern California College of Optometry.