Posterior Subcapsular Cataract: Symptoms, Causes and Treatment
Headlights that flare into starbursts, a phone screen that fades in sunlight and small print that suddenly feels harder to read can all point to a posterior subcapsular cataract. These changes often stand out in bright conditions, and they can arrive faster than you might expect. You may find yourself squinting at a menu, avoiding night drives or wondering why sunny days seem harder on your eyes than they used to. Understanding what sits behind these vision changes can help you make sense of what your eyes are telling you, and when cataract surgery might come into the conversation.
Quick Overview
- A posterior subcapsular cataract is a cloudy area that forms in the back layer of the eye’s lens.
- It may appear at an earlier age than other cataracts, and in some cases it is linked with steroid medicines, diabetes or a past eye injury.
- It can affect near vision, distance vision and vision in bright light.
- How quickly it develops and how much it affects daily tasks can vary from one eye to the next.
- Your symptoms, an eye exam and the impact on your routine usually guide what happens next.
Below, we explain where this cataract forms, why it develops, how it is found and what treatment involves.
What Is a Posterior Subcapsular Cataract?
A posterior subcapsular cataract (PSC) is a type of cataract that forms in the back layer of the lens, directly underneath the posterior lens capsule. It tends to grow faster than other cataracts and can make it hard to see in bright light.
The lens sits behind the coloured part of your eye and helps focus light onto the retina. It is held in place by a thin, transparent bag called the lens capsule. Inside, proteins and lens fibres are normally arranged so the lens stays clear.
As a cataract forms, these proteins and fibres break down and clump together, which clouds the lens. In a posterior subcapsular cataract, this cloudy lens area develops at the back, often near the centre and close to the visual axis that light follows to the retina.
Nuclear cataracts form in the centre of the lens, while cortical cataracts develop in the layer that wraps around it, and each of these types of cataract affects vision in its own way. Unlike nuclear or cortical types, a subcapsular cataract starts at the back of the lens.
How Does a PSC Cataract Affect Vision?
A PSC cataract can cause glare, halos and blurry vision, particularly in bright light. It may affect both near vision and distance vision, and it can progress faster than other cataracts.
A cataract scatters and blocks light entering the eye, so a clear image cannot fully reach the retina. Common signs of a posterior subcapsular cataract include glare and difficulty in bright light, halos around bright lights and double vision in one eye. Light sensitivity may also occur.
You might notice that oncoming headlights feel harsher at night. Reading may become more difficult, and you may find your vision worse in sunlight than indoors.
This type of cataract can show rapid progression and may reduce visual acuity sooner than other cataracts. Over time, the resulting visual impairment can become visually disabling and interfere with everyday activities.
Why Do Posterior Subcapsular Cataracts Develop?
Posterior subcapsular cataracts can develop with ageing, but several risk factors are linked with this type in particular. These include steroid medicines, diabetes, eye injury and radiation exposure.
- Long-term steroid use: Glucocorticoids, a group of steroid medicines, are known to cause this type of cataract, particularly after the age of 40. Both inhaled and oral forms have been linked with a higher risk, and in these cases the clouding may relate to lens cells moving abnormally along the back of the lens capsule.
- Diabetes mellitus: Diabetes is associated with a higher chance of developing this type of cataract.
- Ocular trauma: An injury to the eye can lead to clouding at the back of the lens.
- Radiation exposure: Ionising radiation is a recognised risk factor.
- Eye inflammation and previous eye surgery: Uveitis and procedures such as vitrectomy are associated with a higher risk.
- Short-sightedness: Myopia is also listed among the risk factors.
These risk factors help explain why a posterior subcapsular cataract can appear in younger adults as well as older adults, and they sit alongside the more general reasons behind what causes cataracts.
How Is a Posterior Subcapsular Cataract Diagnosed?
Your eye doctor can usually identify a posterior subcapsular cataract during an eye exam with a slit lamp. This microscope lets them look closely at each part of the eye, including the lens.
An eye exam usually includes a visual acuity test, which measures how clearly you can read letters on a chart. During the slit lamp exam, your eye doctor can see where the clouding sits in the lens.
Your eye doctor will also check other parts of the eye, such as the retina, to look for conditions that could affect your overall eye health. Bringing a list of your current medicines can help your eye doctor interpret what they see and discuss treatment options with you.
What Are the Treatment Options for a Posterior Subcapsular Cataract?
In the early stages, updated glasses, tinted glasses and vision aids may help for a time. Once a cataract affects your everyday life, cataract surgery may be suggested to remove it.
During surgery, the surgeon makes a small incision in the eye and removes the cloudy lens. A clear artificial lens is then placed inside the eye to replace it.
Not every cataract needs to be removed, and the timing usually depends on how much your vision affects reading, driving and other daily tasks.
Cataract surgery restores vision for many patients, although some vision problems may remain. Results vary from one eye to the next. Like any eye surgery, it carries risks, and your eye doctor can explain how these apply to you.
Getting Clarity on Glare and Reading Changes
A posterior subcapsular cataract can progress faster than other cataracts, so noticing early changes in reading and bright-light vision gives you more time to plan. At Armadale Eye Clinic, our ophthalmologists assess cataracts and perform cataract surgery. They can examine your lens closely and explain whether surgery may be suitable for your eyes. Each eye is different, and the right timing depends on your individual situation. To arrange an assessment, please call us on (03) 9070 5753.
Frequently Asked Questions
Can eye drops clear a posterior subcapsular cataract?
There is no proven medical treatment to prevent cataracts, and no studies have shown how to slow their growth. Laboratory studies of compounds such as lanosterol, tested as a way to dissolve cataracts, have produced conflicting results.
Should I stop taking steroids if I have a posterior subcapsular cataract?
Steroid medicines are prescribed for conditions such as asthma, arthritis and inflammatory bowel disease. The condition being treated still needs managing, so any change to your steroid medicine should only be made with medical advice. Your eye doctor can describe what they see in the lens, which can help inform that discussion.
Will I go home on the same day as cataract surgery?
Cataract surgery is usually performed as day surgery. This means you can generally go home on the same day.
Can a cataract come back after surgery?
A cataract cannot form again in the same eye once the cloudy lens has been replaced. The posterior capsule that holds the artificial lens can turn hazy months or years later, which is called posterior capsule opacification. This is usually treated with a laser procedure called YAG laser capsulotomy, and vision may improve within hours.
Are both eyes treated at the same time?
If both eyes have a cataract, one eye is normally treated first. The second eye may be treated a few days or weeks later.
Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
References
Medical News Today. What to know about posterior subcapsular cataracts (medically reviewed, 7 August 2025). https://www.medicalnewstoday.com/articles/posterior-subcapsular-cataract
Carlson J, McBride K, O’Connor M. Drugs associated with cataract formation represent an unmet need in cataract research. Frontiers in Medicine (2022). https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.947659/full
Healthdirect Australia. Cataracts. https://www.healthdirect.gov.au/conditions/eye-diseases/cataracts
Mayo Clinic. Cataracts: Symptoms and causes (14 March 2026). https://www.mayoclinic.org/diseases-conditions/cataracts/symptoms-causes/syc-20353790
Brézin AP, et al. Incidence of Nd:YAG laser capsulotomy following cataract surgery: a population-based nation-wide study (FreYAG1 study). BMC Ophthalmology (2023). https://pmc.ncbi.nlm.nih.gov/articles/PMC10578013/
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