Therapeutics: Understanding Medication- Induced Glare
Minimize your patient’s risk of drug-induced UVR- and photophobia-related conditions.

Siret D. Jaanus, Ph.D., Fullerton, Calif.

Because the eye has a rich blood supply and a relatively small mass, it’s susceptible to certain medications and toxic agents, making it the target of various adverse effects. For this reason, ask your patient during the history portion of his exam whether he’s currently using any prescription or nonprescription medications as well as any herbal and/or nutritional products. Here, I will present medications and herbal products associated with photophobia-related adverse ocular effects and how you can minimize the symptoms of these ocular conditions.
Minimize the risks
To determine whether the medications and herbal and/or nutritional products your patient is using may cause UVR- and photophobia-related adverse ocular conditions, educate yourself on the these two basic categories: 1. Medications and herbal and nutritional products that alter the quality of vision. These agents may induce glare, increase light sensitivity or impair lightdark adaptation. (See “Drugs That Can Alter Quality of Vision,” below.) 2. Medications and herbal and nutritional products that contribute to the development of ocular disorders. These agents may cause disorders — all of which are typically long-term and potentially serious threats to vision. Some examples: antineoplastic agents: (keratitis, scleritis, color-blindness, internal ophthalmoplegia, retinopathy, papilledema, maculopathy, dry eyes, cataract, glaucoma, optic neuritis, blepharitis); and dermatologic agents (keratopathy, dry eye, optic neuritis, night blindness, blepharoconjunctivitis); among other agents. Note the potential link between these two categories — ultraviolet radiation (UVR). A growing body of experimental and epidemiological evidence connects chronic UVR exposure with the development of vision-threatening ocular disorders, such as cataracts. Medications that dilate the pupil (mydriatics) — increasing the amount of UVR entering the eye — or medications that simulate the effects of UVR on the eye (photosensitizers) may increase the risk for the development of UVR-related eye disease. (See “Classes of Drugs That May Cause Photo Sensitivity,” below.) If any of the medications and herbal and/or nutritional products your patient is using are in either of these categories, call his primary-care physician to inform him that use of these agents puts the patient at risk for developing these ocular conditions.
Minimize the symptoms
If a patient presents exhibiting UVR- and photophobia- related adverse effects of medications and herbal and/or nutritional products, call his primarycare physician to see whether the patient can safely discontinue the drug, or herbal or nutritional product in question, whether the primary-care physician can make a reasonable substitution for that specific agent or whether he can decrease the dosage to minimize the ocular side effect. When a patient must continue taking his drugs, herbal and/or nutritional product despite the ocular consequences, however, inform him of the UVR- or photophobia-related adverse ocular effect(s) as well as the reasons he should continue using the medication or herbal and/or nutritional product. To eliminate or minimize the symptoms of the ocular effect, consider prescribing the appropriate spectacle lenses and lens enhancements to both improve your patient’s quality of vision and help him maintain and preserve his vision. For example: An adult using methylphenidate (Ritalin, Novartis), a central nervous system stimulant, presents reporting light sensitivity and glare (mydriatic effect). This patient requires Ritalin to stay focused and perform his job well. Therefore, discontinuing the drug is not an option. So, you call his primary-care doctor about decreasing the dosage. If this patient’s doctor is against a decrease, or after doing so, the patient returns to you reporting the same complaints, you could prescribe a photochromic lens that has anti-reflective coating to minimize this patient’s ocular discomfort and enhance his visual performance under conditions of variable illumination. Another example: A patient with an autoimmune disorder who is using chronic steroid therapy, with possible drug-induced mydriasis and the possibility of steroid-induced glaucoma and drug-related potentiation for cataractogenesis and retinopathy, presents complaining of light sensitivity. You could prescribe UVR-filtering spectacle lenses to decrease ocular UVR exposure and limit the effect of UVR on the lens and retina, cataract growth, along with fixed-tint or photochromic lenses with anti-reflective coatings to minimize light sensitivity. By being vigilantly aware of the role drugs and certain products play in contributing to UVR- and photophobia-related side effects, you can minimize your patients’ risk of experiencing these problems, decrease the possible complications of long-term effects and prevent visual compromise in patients who present with UVR- and photophobia-related adverse ocular conditions.

DRUGS THAT CAN ALTER QUALITY OF VISION
• Photosensitizers work at a molecular level to increase energy absorption
from ultraviolet radiation (UVR) and increase sensitivity to
light. Individuals using these medications become more susceptible to
the potential adverse effects of UVR.
• Mydriatics dilate the pupils, increasing the amount of light entering
the eye, thereby enhancing light sensitivity and increasing the potential
ocular phototoxic effects of UVR.
• Miotics constrict the pupil, limiting the amount of light and hindering
light-to-dark adaptation distance judgement ability. In patients using
these agents, normal papillary function to modulate light is impaired.

CLASSES OF DRUGS THAT MAY CAUSE PHOTOSENSITIVITY
• Antiarrhythmics (Amiodarone)
• Antibiotics (for example, fluoroquinolones,
macrolides, sulfonamides, tetracyclines)
• Anticholinergics
• Anticonvulsants (Phenytoin, carbamazepine)
• Antidepressants
• Antihistamines
• Antipsychotic agents
• Cardiac agents (for example, Angiotensin converting
enzyme inhibitors, Calcium channel blockers, Thiazide
diuretics)
• Central nervous system stimulants
• Digitalis glycosides
• Herbal Products (for example, St. John’s Wort
(Hypericum perforatum), Parsnip (Pastinaca sativa),
Pimpinella (Pimpinella major), Rue (Ruta graveolens)
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Oral contraceptives
• Phenothiazines
• Psoralens (psoriasis management)
• Retinoids (isotretinoin).

Dr. Jaanus is a professor of pharmacology at the Southern California College of Optometry in Fullerton, Calif. She authored and co-edited “Clinical Ocular Pharmacology,” and Transitions Optical’s “Ocular Effects Associated with Medications.” E-mail her at sjaanus@scco.edu.