Blurry vision, changes in eye pressure, dry eyes and several other eye symptoms may occur from adverse drug effects. Commonly prescribed medications like antibiotics, heart medications, bone drugs, and diuretics affect the whole body including the eyes, which are particularly vulnerable to adverse drug effects. Rather than dismissing the blurry vision or worsening of macular degeneration to age and family history, check on the medications that you take. Early detection of drug-induced damage to the eyes may just save you from irreversible ocular damage and vision loss. It is important to ensure that your eye health is nutritionally fortified and optimized if these medications have to be used.

Changes to eye health that seem to have no apparent cause may be overlooked and related to the use of daily or over-the-counter medications. Adverse drug side effects to the eye may be mild and temporary or may lead to serious, permanent changes in eye health and even blindness. While we may not think of medications affecting the eyes, it is a very real concern. It has led to an outcry within the optometry field to be vigilant about asking patients about their prescription use, but these concerns may still be overlooked. It is up to you to be vigilant about protecting your eyes.

How Drugs Affect Eye Health

Once a drug has entered the bloodstream, it can reach eye tissues because of the rich blood supply permeating into the different fluids of the eye. The small size of the eye relative to other parts of the body also makes the eye tissues more vulnerable. Drug molecules can enter the eye and come in contact with various parts of the eye and either accumulate in the eye or exit out of the eye. The three most common sites that drug molecules accumulate in are the lens, cornea, and the vitreous humor, the jelly-like fluid that fills the eyeball behind the lens and in front of the retina.

Drugs can also affect the eye lids. If the drug molecules get into the vitreous humor, it takes longer to clear due to the slow rate of fluid movements. Those who have kidney or liver problems or struggle with detoxification have a higher risk of the drug-eye adverse effects as drug toxins are not cleared out as quickly.

Some drugs make the eye more vulnerable to UV radiation, which increases the likelihood of oxidative stress to the lens. Other drugs alter tear production, increase or decrease pressure inside the eye, increase nearsightedness, change pigmentation in various parts of the eye, deposit lipids or other compounds that affect function in the lens, cornea, retina, etc. Changes in color vision, flickering vision, vein occlusions with the eye, and changes in the shape of the lens or cornea may occur. Some drugs cause retinal detachment, conjunctivitis, watery eyes, impaired eye muscle function, changes in the pupil sizes and accommodation and other disorders. The list of possible adverse eye effects is astonishing. Unfortunately, they can be easily overlooked or dismissed.

Here are some common drugs that you need to be aware of that impact eye health. Check on your parents’ medications too. The elderly are often on one or medications that may significantly impact eye health which causes their glaucoma or cataracts to worsen, not due to age alone. Eye adverse effects also occur in children and even in unborn children via maternal use of drugs.

Analgesics/ Pain Relief: Chronic aspirin use may cause yellowing of vision.

Anti-allergy: Antihistamines like Benadryl and Chlor-tremeton reduce normal tear and mucous production in the eye, causing dry eyes. These drugs can also cause unequal or dilated pupil size, blurred vision and decreased accommodation.

Anxiety/ Sedatives: Valium and other benzodiazepines can cause blurry vision, double vision, unequal pupil size, eye lid spasms, increased sensitivity to light and allergic conjunctivitis.

Antibiotics/ Anti-Infective Drugs: Sulfonamides, tetracyclines – especially minocycline, linezolid/Zyvox, ethambutol, Plaquenil/hydroxychloroquine, Levaquine, Cipro (fluoroquinolones) and others can cause toxic side effects to the eye. Effects may include conjunctivitis, optic nerve inflammation and damage, changes in vision acuity, eye muscle paralysis, irreversible retinal damage, retinal detachment, blindness, eye lid drooping, light sensitivity, macular degeneration, glaucoma, hemorrhage of blood vessels in the eye, and double vision, etc.

Anticancer Drugs: Tamoxifen has been shown to cause macular edema which can progress to vision loss. Other tamoxifen effects include crystal deposits in the retina and cornea. Docetaxel and paclitaxel can cause glaucoma.

Anticholinergics: This type of drug is used in many settings such as sedation, sleep aids, cold medications, nasal decongestants, anti-diarrheal, and digestive disorders. Dry eyes, changes in pupil reaction to light, and unequal pupil size may occur.

Antidepressants: The older tricyclic antidepressants (e.g. Pamelor, amitriptyline) can cause trouble with visual focus and accommodation, dilated pupils, dry eyes, double vision, and glaucoma. Long-term selective serotonin reuptake inhibitors (SSRI’s) like Prozac have been suggested to affect blood vessels to the optic nerve, and cause acute glaucoma, blood clots in the retinal vein, and acute optic nerve injury.

Anti-Inflammatory: Corticosteroids (oral, topical, nasal, inhalation) are well-known for their role in causing cataracts and amblyopia or lazy eye, especially in children. Increased eye pressure, eye swelling, retinal injury with vision loss, and viral infections of the eye may occur with chronic steroid use. NSAIDs like ibuprofen may cause blurred vision, changes to eyeglass prescription, double vision, color vision changes, and dry eyes. Light sensitivity and retinal changes may occur with other NSAIDs.

Anti-seizure: Phenytoin/Dilantin and carbamaepine/Tegretol may cause uncontrolled movements/ nystagmus of the eye and blurred vision.

Bisphosphonates/ Bone Drugs: Fosamax, a popular bisphosphonate osteoporosis treatment bone drug with other known severe side effects, can cause dangerous severe inflammation in various parts of the eye, such as uveitis, scleritis, and the eye socket. It’s not just Fosamax, the intravenous bisphosphonate drugs can also provoke serious eye inflammation.

Bladder Drugs: Flomax and other bladder support drugs for men and aging prostates and women with bladder dysfunction make cataract surgery more difficult due to “intraoperative floppy iris syndrome”.

Blood Sugar: Oral anti-diabetic medications increase sensitivity to the sun making the eye more susceptible to the cataracts and macular degeneration. Other effects may include eye muscle paralysis, double vision, and optic nerve inflammation.

Blood Thinners/ Anticoagulants: Coumadin, warfarin, heparin, and other blood thinners increase the risk of bleeding in the retina and edema within the eye.

Cardiovascular Medications: Beta blockers can affect eye pressure, tear production, and glaucoma. Water pills or diuretics like HCTZ or hydrochlorothiazide may cause dry eyes and affect tear make-up and increase nearsightedness. Antiarrhythmic drugs, especially amiodarone, increase sensitivity to light and cause lipid deposits in the lens and cornea. Vision loss and changes may occur. Digitalis/Digoxin may cause toxic effects to the optic nerve and retina, changes in color vision, halos, and visual sensation. Blood pressure meds used too aggressively or low blood pressure affect eye circulation and make the eye more stressed and susceptible to damage. Statin medications can cause cataracts, injure the eye muscle and other adverse effects.

Erectile Dysfunction: Viagra/sildenafil and Cialis/tadalafil divert blood away from the head which can affect vision quality and interfere with nerve transmission within the retina. These drugs can also cause ischemic optic neuropathy causing loss of vision because of changed blood flow to the optic nerve and retinal artery.

GERD/ Antiulcer: Tagamet and Zantac, popular over-the-counter antacids, may cause blurred vision, photophobia, conjunctivitis, and color changes.

Hormones: The Mayo Clinic describes eye pain and blurred or double vision occurring with Synthroid or levothyroxine use. Oral contraceptives/ birth control pills may cause increased eye blood pressure and glaucoma, swelling in the macula, and blood clots within the retina leading to vision loss. HRT/ hormone replacement therapy or estrogen can change the shape of the lens and even prohibit the ability to wear contact lenses. There is also increase risk of blood clots in the eye and optic nerve inflammation.

Migraine: Imitrex/sumatriptan has been shown to cause corneal changes in animals and acute glaucoma in humans.

Stimulants: Ritalin can affect accommodation and lead to blurry vision.

This list of medications that causes adverse eye side effects is not all inclusive. The intention of this article is meant for you to rethink your eye health and check your medications. America is a nation of pill-poppers and drug toxicity is a massive problem. When a medication deposits its molecules in delicate eye tissues, it creates toxic changes if the medication is not cleared or if the eye lacks a buffering antioxidant capacity to block the adverse effects.

Many of these same prescription drugs rob the body of nutrients that the eyes need. Several of these medications and drug-nutrient interaction affect how the mitochondria work in the eye which creates another toxic layer of dysfunction. Protection of the eye mitochondria and removal of things that damage mitochondria is another critical concern. Sometimes eye and vision health returns once the drug is discontinued. In other circumstances, eye health remains compromised or even permanently lost. The overall goal in any circumstance is to prevent, protect and fortify the eye. 

Diets frequently lack the proper nutrients. If you are on medications, the odds are on some level the eye is being affected either by direct toxic drug effects or by drug-nutrient depletions. Prevention and nutritional support is absolutely critical to keep your eyes healthy. If you have the discipline to brush and floss your teeth twice a day, what about your self-care for your eyes? If you have noticed vision changes, seek appropriate care and use more intensive nutritional support. Take this information and apply it to the quote by J Lubbock, “What we see depends mainly on what we look for”. What are you “looking at” today?