PCO, PCF, YAG, “Secondary Cataract” – How Should We Communicate this to Patients?

Dr. Alan N. Carlson provides the following information in response to two of the most commonly asked questions after cataract surgery: “why has my vision decreased after cataract surgery?” or “why do I need to have a laser treatment after cataract surgery?”

Remember that the cataract is the former lens inside the eye that has become opaque or cloudy.  (Hence the term cataract which can be traced back to both Greek and Latin origins to a term ascribed to a waterfall or the cloudiness of “down rushing” water.)  


The perfect cataract operation removes 99% of the cataract, purposely leaving behind a portion of the capsule or that 1% of the lens that remains as the support for the artificial lens or the new intraocular lens implant.  In almost every case, healing along with some degree of capsular “clouding” occurs.  This is not preventable and in about 30% of cases, that clouding will affect vision to the extent that treatment or a laser intervention is needed.  This is more likely to occur in patients who are younger or have certain types of cataract or uveitis or diabetes.  The Nd-YAG (or simply “YAG”) laser is a very precise and rapid solid state laser that opens and clears that central portion of the vision and converts the capsular “bag” to a capsular “tire” still supporting the intraocular lens so you can see through the central portion that is now clear.  The procedure is safest when performed at least 3 months after the original cataract surgery and I recommend that diabetic and uveitis patients be well controlled prior to treatment.  No procedure is completely free from risk but as long as the intraocular lens is secure and well positioned and the patient is able to control their fixation during the procedure, the risks are minimal.  Discuss the specifics of your case and any additional risk posed by your condition with your eye care provider.  I typically recommend patients use topical corticosteroids 4 times per day for 7-10 days after the YAG procedure along with any other medications they were using previously.  Patients with pre-existing glaucoma will need to also have their pressure monitored.  Avoid strenuous exercise for 36 hours after the procedure.  Brand new floaters are not uncommon after this procedure; however, if you see a shower of new floaters, particularly if this occurs along with flashes of light, this combination warrants prompt evaluation to rule out something more significant such as a retinal detachment.

Of note, PCO (posterior capsular opacification) and PCF (posterior capsular fibrosis) are very similar and do not need distinction for this purpose.  The term “secondary cataract” has also been used to describe PCO and unfortunately this is very confusing to patients as cataracts do not “grow back” after they are removed.  The process does result from a proliferation of the original cortical epithelial cells from the cataract that have replicated and migrated across the posterior capsule: however, this is not a regrowth of the cataract itself.

PCO = Posterior Capsular Opacification