When most people think about cataracts, they picture an age-related change that gradually clouds the eye’s natural lens over time. But what many don’t realise is that certain medicines can also play a role in cataract formation. One of the best-known groups in this regard is the phenothiazines — a class of older antipsychotic medications that, when taken for long periods, can affect the clarity of the lens.
If you or someone you care for is taking a phenothiazine, it’s worth knowing how these drugs can impact your eyes, what symptoms you should be alert to, and what to expect if you ever need cataract surgery while on treatment. This article will guide you through everything you should know, from the science behind the changes to practical advice on eye care and surgery planning.
What Are Phenothiazines?
Phenothiazines are a group of medicines that were widely prescribed as antipsychotics from the 1950s onwards. They were groundbreaking in their time, helping people with conditions such as schizophrenia, bipolar disorder, and severe behavioural disturbances manage symptoms that were once thought untreatable. Common examples include chlorpromazine, thioridazine, prochlorperazine, trifluoperazine, and fluphenazine.
These drugs work mainly by blocking dopamine receptors in the brain, which helps to reduce hallucinations, delusions, and agitation. However, they also interact with other systems in the body, which explains why they can cause a range of side effects beyond the brain. One such effect, noticed after years of widespread use, is their impact on the eyes.
While phenothiazines are now prescribed less often than newer antipsychotics, some people remain on them for long-term management. That’s why understanding their potential link to cataracts remains important.
How Phenothiazines Affect the Eyes
You might wonder how a drug taken for the mind can influence something as distant as the eye lens. The answer lies in the way phenothiazines interact with light and ocular tissues.
Pigment deposition
One of the most recognisable effects of phenothiazines is pigment deposition. Tiny dark specks can form in the front part of the lens and sometimes in the cornea. These aren’t just cosmetic: as the deposits increase, they can scatter light, reduce clarity, and contribute to cataract formation.
Ultraviolet interaction
Phenothiazines are photosensitive. When they accumulate in the eye, they can interact with UV light from the sun. This interaction generates oxidative stress and free radicals, which can damage the proteins in the lens. Over time, the proteins clump together, leading to clouding of the lens — in other words, cataracts.
Dose and duration
The risk of eye changes goes up the longer and higher the dose of phenothiazine therapy. People who take these drugs for many years, particularly at strong doses, are more likely to develop pigment deposits and cataracts compared to those on lower or shorter courses.
Not everyone is affected equally
It’s also true that not every person on phenothiazines will develop cataracts. Genetics, general health, and lifestyle factors (like smoking, diabetes, and UV exposure) can either increase or reduce your personal risk. So it’s best to think of phenothiazines as an added risk factor rather than an inevitable cause.
What Symptoms Should You Look Out For?
If you’re on phenothiazines, it’s useful to know the early warning signs of cataracts. Many start subtle but progress slowly over time.
- Blurry or cloudy vision: A gradual loss of clarity is the most common symptom. It may feel like you’re looking through a misty window.
- Glare and halos: Bright lights, especially at night, may seem harsher than before, sometimes with rings or streaks around them.
- Frequent changes in glasses: If your prescription seems to keep changing without improving your vision much, cataracts may be to blame.
- Colours looking duller: Cataracts often give vision a yellowish tint, making colours less vibrant.
- Difficulty with contrast: Reading in dim light or seeing fine details may become harder.
Even if you don’t notice symptoms, your optician or ophthalmologist may spot pigment deposits or early lens changes during a routine slit-lamp examination.
What Does the Research Say?
Researchers first noticed the link between phenothiazines and cataracts in the 1960s, and many studies since have confirmed the association. Some key findings include:
- Long-term chlorpromazine users developed characteristic stellate (star-shaped) cataracts.
- The risk rises with higher doses and longer duration of use.
- Even when other risk factors like diabetes and steroid use were accounted for, phenothiazine users still showed a higher rate of cataract extraction compared to the general population.
That said, modern prescribing practices tend to use lower doses or switch to newer medications sooner. This means the cataract risk today may not be as high as it was in earlier decades. Still, the association is strong enough that most guidelines recommend regular eye checks for people on long-term phenothiazines
Practical Steps if You’re Taking Phenothiazines
If you’re on phenothiazine therapy, here are some straightforward steps to protect your vision:
- Get a baseline eye check: Have a full examination early on in your treatment to record the condition of your lenses and corneas.
- Schedule regular reviews: Aim for yearly check-ups, or more often if your eye doctor recommends it.
- Tell your doctor about changes: Don’t ignore new symptoms like glare, blur, or colour shifts.
- Protect against UV light: Sunglasses that block UV-A and UV-B rays can reduce light-induced damage.
- Control other risks: Managing diabetes, avoiding smoking, and eating a diet rich in antioxidants can all help slow cataract progression.
- Discuss options with your psychiatrist: If eye changes are significant, your psychiatrist may consider alternative medications. Never stop your psychiatric medicine without professional guidance.
Cataract Surgery Basics
If cataracts progress enough to interfere with your daily life, surgery is the only way to restore vision. The procedure involves removing the cloudy natural lens and replacing it with a clear artificial lens called an intraocular lens (IOL).
Modern cataract surgery, usually performed by phacoemulsification, is highly effective. Through a tiny incision, the surgeon breaks up the lens with ultrasound, removes it, and inserts the IOL. Most people notice a big improvement in their vision within days, with recovery usually complete within a few weeks.
Special Considerations for Patients on Phenothiazines
For someone with a history of phenothiazine use, cataract surgery can still deliver excellent results — but there are some unique factors that your surgeon will consider.
- Pre-surgery planning: Extra care is taken to assess corneal health, pigment deposits, and lens capsule strength.
- Surgical technique: Surgeons may adjust their technique to protect the cornea and manage any pigment that becomes dislodged during the operation.
- Lens choice: Monofocal lenses are often preferred over multifocal designs, as pigment-related changes can reduce contrast sensitivity. Some surgeons may consider light-adjustable lenses to fine-tune vision after healing.
- Post-surgery monitoring: More frequent follow-ups may be recommended to check for inflammation, pigment dispersion, or pressure changes in the eye.
With the right planning and an experienced surgeon, outcomes are usually very positive, and many patients regain clear, comfortable vision.
Prognosis and Outlook
The good news is that cataracts related to phenothiazine use are treatable, and most patients achieve strong visual outcomes after surgery. While there may be a slightly higher risk of surgical challenges compared to standard age-related cataracts, the difference is not dramatic in experienced hands.
The key is awareness and early action. Knowing your risks, having regular eye checks, and working closely with both your psychiatrist and ophthalmologist ensures that cataracts are managed at the right time and in the safest way.
Frequently Asked Questions (FAQ)
1. If I stop taking phenothiazines, will my cataracts go away?
Stopping phenothiazines may reduce further drug-related stress on the eye, but it does not reverse existing cataracts. Once the lens proteins have clumped together and clouded the lens, that change is permanent. The cloudiness can only be treated by surgery, which replaces the lens with a clear artificial implant. What you can expect is that discontinuing the medication may slow down any new damage, especially if combined with good UV protection and healthy lifestyle choices.
2. How often should I see an eye specialist while on phenothiazines?
It’s generally recommended to have an annual eye examination, but if your doctor finds pigment deposits or early cataracts, you may need check-ups every six months. The goal is to track subtle changes before they significantly affect your vision. These appointments usually involve slit-lamp examination, vision testing, and sometimes retinal scans to rule out other issues. Regular reviews also create a baseline for your surgeon if you eventually need cataract surgery.
3. Can an optician detect phenothiazine-related changes?
Yes, many opticians can spot early lens changes or pigment deposits during a routine slit-lamp exam. However, these changes can be subtle, and not all will have the training to interpret them in detail. If there is any suspicion, you’ll likely be referred to an ophthalmologist for confirmation and monitoring. Having both an optician and an ophthalmologist involved in your care ensures nothing important is overlooked.
4. Are newer antipsychotic medications safer for the eyes?
Newer “atypical” antipsychotics generally carry a lower risk of cataract formation compared to older phenothiazines. This is partly because they don’t accumulate in the same way in the eye tissues and are less likely to cause pigment deposition. That said, no psychiatric medication is entirely free of side effects, and each comes with its own risks and benefits. The decision to switch should always balance mental health stability with eye safety, in consultation with both your psychiatrist and ophthalmologist.
5. Does cataract surgery carry extra risks for phenothiazine users?
Phenothiazine-related cataracts can sometimes be more complex to remove because pigment deposits or capsule changes make the surgery technically more delicate. Surgeons may need to adjust their technique to protect the cornea and manage liberated pigment. Despite these challenges, experienced surgeons usually achieve excellent outcomes for patients with this history. The most important factor is having a thorough pre-surgery assessment so your surgeon knows exactly what to expect.
6. Will I still need glasses after surgery?
This depends largely on the type of intraocular lens you receive and your individual eye measurements. A standard monofocal lens is the most common choice and usually gives clear distance vision, meaning you’ll still need reading glasses. Multifocal or extended depth of focus lenses are options, but they may not be ideal if pigment changes have affected your eye’s contrast sensitivity. Your surgeon will recommend the option that balances clarity, safety, and your lifestyle needs.
7. Can pigment deposits in the cornea affect vision permanently?
Pigment on the cornea can scatter light and sometimes reduce vision, especially if deposits are dense or central. During surgery, your surgeon takes steps to prevent pigment from causing long-term problems, such as using protective gels and careful irrigation. In many cases, these deposits do not cause permanent loss of clarity once the cataract is removed. However, ongoing monitoring is important to ensure the cornea stays healthy over time.
8. How soon after cataract surgery will my vision improve?
Most people notice clearer vision within a few days, though it may take a few weeks for your eyes to fully stabilise. The speed of recovery depends on your eye health, how complex the surgery was, and whether you had significant pigment or capsule changes. During this period, your surgeon will monitor you closely to ensure the cornea, capsule, and retina are healing properly. It’s important to follow all aftercare instructions to maximise your recovery.
9. Will UV-blocking sunglasses make a difference?
Yes, UV protection is particularly important for patients on phenothiazines because these drugs make the lens more sensitive to light damage. Quality sunglasses that block both UV-A and UV-B can help reduce oxidative stress in the eye. Over time, this can slow down the progression of cataracts and make a meaningful difference in preserving vision. Wearing them consistently when outdoors is a simple but effective preventive step.
10. Can cataracts come back after surgery?
Once the cloudy natural lens is removed, it cannot become a cataract again. However, some patients develop posterior capsule opacification (PCO), where the thin membrane that holds the new lens becomes cloudy months or years after surgery. This can feel like the cataract has returned, but it is easily treated with a quick laser procedure in the clinic. After this, vision usually clears again, and the problem rarely recurs.
Final Thoughts
Living with cataracts can be frustrating, especially when they develop as a side effect of essential medication such as phenothiazines. The important thing to remember is that while these drugs can increase your risk of lens changes, modern ophthalmology has excellent tools to help you. Cataract surgery remains one of the safest and most effective procedures worldwide, and with the right planning, patients on long-term phenothiazines can achieve excellent visual results.
If you are on phenothiazines and have noticed changes in your sight, the first step is not to panic but to get a proper eye examination. Early monitoring means your eye specialist can track lens changes and advise you on when surgery might be appropriate. Combining good lifestyle choices, UV protection, and regular reviews gives you the best chance of maintaining clear and comfortable vision for as long as possible.
When the time comes for cataract surgery, having an experienced team on your side makes all the difference. At the London Cataract Centre, our team understands the added considerations that come with phenothiazine-related cataracts. From careful preoperative planning to tailored lens choices and attentive aftercare, we ensure that your treatment is customised to your needs. Taking that step could bring you closer to clearer, more confident vision, without unnecessary delays.
References
- Isaac, C., Walker, R. and Boyd, T. (1991) ‘Association between antipsychotic medication and cataract extraction’, Archives of Ophthalmology, 109(2), pp. 253–256. Available at: https://jamanetwork.com/journals/jamaophthalmology/fullarticle/638916
- Barsa, R., Epstein, D. and Rosenthal, R. (1965) ‘Ocular changes associated with long-term chlorpromazine therapy’, JAMA, 192(1), pp. 63–66. Available at: https://jamanetwork.com/journals/jama/fullarticle/655954
- Gopalakrishnan, S., Krishnadas, R. and Thomas, P. (1985) ‘Ocular changes associated with long-term phenothiazine therapy’, Indian Journal of Ophthalmology, 33(1), pp. 13–17. Available at: https://journals.lww.com/ijo/fulltext/1985/33010/ocular_changes_associated_with_long_term.6.aspx
- Lee, V. and Chan, T. (2022) ‘Ocular toxicity of phenothiazine’, Hong Kong Journal of Ophthalmology, 26(1), pp. 13–18. Available at: https://journals.lww.com/hjop/fulltext/2022/04000/ocular_toxicity_of_phenothiazine.13.aspx