What is posterior capsule opacification (PCO) after cataract surgery?

If you had cataract surgery and your vision was crisp for months or years — then gradually became misty again — you are probably describing posterior capsule opacification (PCO). It is the most common late change after cataract surgery, and the fix is a quick outpatient laser.

The short answer

Posterior capsule opacification is a thickening of the natural membrane behind your intraocular lens implant. It is not a cataract coming back and it does not mean anything went wrong with your surgery. It is treated with YAG laser capsulotomy.

Why PCO happens

During cataract surgery the cloudy natural lens is removed but the very thin capsule that supported it is left in place to hold the new lens implant. Over time, a small number of remaining lens cells can grow on the back of this capsule, making it hazy. Light no longer passes cleanly through and vision becomes misty, glary or dim.

Typical symptoms

- Vision becomes gradually blurred, weeks to years after cataract surgery

- Reading print looks less crisp

- Halos, glare or ghosting appear at night

- Colours seem less vibrant

- Symptoms are similar to the original cataract

How PCO is diagnosed

An ophthalmologist confirms PCO with a slit-lamp examination. The lens implant looks clear but the membrane behind it shows opacity. Once confirmed, YAG laser capsulotomy is offered as a definitive treatment.

Why YAG laser is the answer

YAG laser capsulotomy uses a focused pulse of laser to make a small opening in the cloudy capsule directly behind the lens implant. Light passes through cleanly again, and vision usually improves within hours. The procedure takes 5–10 minutes per eye, is painless and is done in the clinic without needing hospital admission.

Book a consultant-led YAG assessment

Ms Tahmina Pearsall offers consultant-led YAG laser capsulotomy from £450 per eye across UK clinics. Visit the YAG laser capsulotomy clinic page to arrange an assessment.