Chemotherapy, a powerful tool in cancer treatment, works by targeting rapidly dividing cancer cells throughout the body. While effective, these potent medications can also affect healthy cells, leading to various side effects. Among these, changes to vision can occur, ranging from mild and temporary discomfort to, in rare instances, more significant and lasting visual impairment. This article explores how chemotherapy can impact your eyes and what to expect.
Understanding the Risk of Blindness
While complete blindness from chemotherapy is an extremely uncommon outcome, the vast majority of visual side effects are not severe and often resolve after treatment. Chemotherapy drugs can affect rapidly dividing cells, including those in the eyes. The eye’s complex structures are resilient, and temporary vision alterations are more frequent than permanent vision loss.
How Chemotherapy Impacts Vision
Chemotherapy drugs can affect various parts of the eye and the intricate visual system through several mechanisms. Direct toxicity can harm the epithelial cells of the cornea and conjunctiva, potentially leading to conditions such as keratitis, which is inflammation of the cornea, or conjunctivitis, an inflammation of the clear membrane covering the white part of the eye. Some medications can also induce inflammation within the eye, causing conditions like uveitis, which affects the middle layer of the eye, or scleritis, an inflammation of the white outer layer of the eyeball.
Neurotoxicity from chemotherapy can impact the optic nerve and oculomotor nerves, which control eye movement, resulting in various visual disturbances. It can also alter the tear film, leading to dry eye syndrome or affecting tear production. Changes in eye pressure (glaucoma) or accelerated development of cataracts (clouding of the eye’s lens) can also occur. Some drugs may also cause vascular effects on retinal blood vessels, potentially leading to retinal hemorrhages or ischemia (reduced blood flow).
Common Chemotherapy Drugs and Their Visual Effects
Specific chemotherapy drugs or classes of drugs are more frequently linked to particular visual side effects. For instance, antimetabolites like 5-fluorouracil (5-FU) can cause blurred vision, eye pain, light sensitivity, excessive tearing, eye irritation, and inflammation of the cornea and conjunctiva. Permanent excessive tearing can sometimes result from fibrosis of the tear ducts with 5-FU.
Vinca alkaloids, such as vincristine, are known for their neurotoxic effects and can lead to optic neuropathy or, rarely, cortical blindness. Cisplatin, a platinum-based drug, can cause retinal toxicity, including ischemic retinopathy, and may result in granular pigmentary deposits and altered color vision. High doses of cytarabine are associated with corneal toxicity, including keratitis, hemorrhagic conjunctivitis, and blurred vision. Taxanes, like docetaxel and paclitaxel, can cause a range of ocular issues, with excessive tearing being a common side effect of docetaxel, and both drugs linked to cystoid macular edema and optic neuropathy. Tamoxifen, a hormone therapy, has been associated with retinal changes and optic neuropathy.
When to Seek Care and Managing Vision Changes
It is important to promptly report any new or worsening vision symptoms to your healthcare provider during or after chemotherapy. Immediate medical attention is warranted for:
Sudden severe eye pain
Sudden loss of eyesight
Seeing halos around lights
Increased light sensitivity
An eye infection that worsens or does not improve within three days of treatment also requires prompt evaluation.
For less severe symptoms, various management strategies can help. Dry eyes, a common side effect, can often be managed with over-the-counter, preservative-free artificial tears. Warm compresses can help alleviate symptoms of red, swollen eyelids or watery eyes. If excessive tearing is due to blocked tear drainage passages, your eye doctor might suggest a procedure to improve drainage. Wearing sunglasses can help with light sensitivity. Your oncology team and eye care specialists can work together to determine the cause of vision changes and recommend appropriate interventions, which may include adjusting the chemotherapy regimen or prescribing specific eye medications.