What is a secondary cataract? Often it’s called PCO or posterior capsule opacification. It’s a healing reaction. Patients often ask when they’ve had cataract surgery if the cataract can come back and the truth is the cataract itself cannot come back. We’ve removed the lens that was cloudy, but we leave behind the membrane to hold the new plastic lens, and this is critical to the safety of the operation and to get a really good accurate outcome for the patient.

But because we’ve left behind a biological structure, the patient’s healing reactions can kick into action. The membrane can recognise that it’s been injured. I mean, it’s a controlled injury, but nevertheless, it’s an injury to a structure in the eye. The healing reaction can result in thickening and scarring of that membrane. So the membrane turns from being a lovely crystal-clear structure to look through to something like a frosted glass that you might see in a bathroom window. Of course, this scatters the light impairs the quality of vision for the patient.

Thankfully it’s incredibly easily treated.  We have a laser, called the YAG laser, which is a simple outpatient procedure. The laser is mounted on the lamps that we always used to look at you when you come to the clinic and that your optometrist will also use to examine your eye when you attend for a routine eye check. The procedure takes about a minute and is completely painless.

What we’re doing is, making a window in that membrane behind the plastic lens and that restores clarity the next day. There might be one or two extra little floaters or little bits of debris from where we’ve cleared the membrane out the way, but the patient’s immune system will gobble them up and will be completely clear within 2 or 3 days.

You can never say never in medicine, but occasionally the membrane will grow back. But that’s less than 1 in 1,000 patients, so for most people, the treatment of secondary cataracts or the posterior capsule opacification, the PCO, the treatment of that is the end of the journey, and that patient can look forward to maintaining an excellent quality of vision.