A secondary cataract is a clouding that develops on the thin membrane behind an artificial lens implant after cataract surgery. Despite the name, it isn’t actually a new cataract. The original cataract can’t grow back once it’s been removed. What happens instead is that leftover cells on the lens capsule (the natural “bag” that held your original lens) gradually multiply and create a hazy film that blurs your vision. The medical term is posterior capsule opacification, or PCO, and it’s the most common complication following cataract surgery. Roughly 1 in 10 people who have cataract surgery will develop it.
Why It Happens After Cataract Surgery
During cataract surgery, the cloudy natural lens is broken up and removed, but the surgeon intentionally leaves the lens capsule in place. This capsule serves as a support structure for the new artificial lens (called an intraocular lens, or IOL) that gets implanted. The problem is that microscopic lens cells remain on the capsule wall. Over months or years, these residual cells can grow and spread across the back surface of the capsule, forming a cloudy layer that sits directly behind the implant.
The timeline varies. Some people develop PCO within a year of surgery, while others don’t notice any cloudiness for several years. In a study of over 700 patients who had cataract surgery, about 11.8% developed a secondary cataract during the follow-up period. Younger patients tend to be at higher risk because their lens cells are more active and prone to regrowth.
How It Affects Your Vision
The symptoms of a secondary cataract closely mimic the original cataract, which is why it can feel like your cataract “came back.” Vision that was sharp after surgery gradually becomes hazy or blurred again. You may notice trouble seeing in sunlight or bright lights, halos or starbursts around lights at night, and reduced contrast, making it harder to distinguish objects against similarly colored backgrounds. Reading and driving at night often become more difficult first, since those tasks demand the sharpest optics.
Because the clouding builds slowly, some people don’t realize how much vision they’ve lost until it’s pointed out during a routine eye exam. If you had excellent results from your cataract surgery but your vision has been quietly declining, PCO is one of the likeliest explanations.
Treatment With YAG Laser Capsulotomy
The standard treatment is a quick, painless laser procedure called a YAG laser capsulotomy. Your eye doctor uses a focused laser beam to create a small opening in the cloudy capsule behind your lens implant. Light can then pass through cleanly again, restoring the clear vision you had after your original cataract surgery.
The entire procedure is done in an office or outpatient setting. Your eye is numbed with drops and dilated beforehand, then the laser work itself takes only a few minutes. There are no incisions and no stitches. Once it’s finished, you can go home the same day. Most people notice improved vision within a day or two, though it can take a bit longer for some. The most common side effect is a temporary increase in floaters (small spots or squiggly lines drifting across your vision), which typically fades within a few days. Minor soreness or discomfort is possible but usually mild.
The procedure is a one-time fix. Once the opening is made in the capsule, the cloudiness in that area doesn’t grow back.
Risks of the Procedure
YAG laser capsulotomy is considered very safe, but no procedure is risk-free. A large review of outcomes found the following complication rates:
- Temporary pressure spike in the eye: 1.73% of cases. People with a history of glaucoma are significantly more likely to experience this.
- Inflammation inside the eye: 0.74%
- Swelling of the central retina: 0.74%
- Retinal detachment: 0.16%
- Retinal tear: 0.08%
The vast majority of patients have no complications at all. Your eye doctor will typically check your eye pressure shortly after the procedure and schedule any follow-up visits as needed, though for most people, the next routine annual exam is sufficient.
What the Procedure Costs
If you’re on Medicare, the national average total cost for YAG laser capsulotomy is $576 at an ambulatory surgical center and $836 at a hospital outpatient department, based on 2026 Medicare payment rates. Medicare covers 80% of the approved amount, leaving the patient responsible for 20%. In practical terms, that works out to roughly $115 out of pocket at a surgical center and $167 at a hospital outpatient department. Private insurance plans typically cover the procedure as well, though your specific copay or coinsurance will depend on your plan.
Can a Secondary Cataract Be Prevented?
You can’t fully prevent PCO, but the type of artificial lens implanted during your original cataract surgery plays a meaningful role in reducing risk. Lens implants with a square, sharp-edged design have been shown to significantly lower PCO rates compared to implants with rounded edges. The sharp edge acts as a physical barrier, making it harder for leftover lens cells to migrate across the back of the capsule. The material of the implant matters too: hydrophobic acrylic lenses (which repel water) tend to have lower PCO rates than hydrophilic (water-attracting) acrylic lenses.
These are decisions your surgeon makes at the time of your original cataract surgery, so they aren’t something you can change after the fact. But if you’re preparing for cataract surgery and want to minimize your chances of needing a follow-up laser procedure, it’s worth asking your surgeon about the edge design and material of the lens they plan to use.