rx perspective
Preventing Post-Op Macular Edema
It's a bigger problem than many doctors realize, but NSAIDs can help to change that.
By Michael B. Raizman, M.D.

Macular edema following cataract surgery is surprisingly common. It occurs in 4% to 12% of routine phaco cases (depending on whether you define macular edema as detectable by fluorescein angiography or clinically significant, i.e. reducing the pa-tient's vision). With about a million cataract surgeries being performed every year, that's a lot of post-surgery patients who aren't seeing as well as they should.

It is possible to prevent this. Macular edema appears to be caused by prostaglandins that are released from the iris during surgery. Several studies have shown that it can be minimized -- or prevented altogether -- by using topical nonsteroidal anti-inflammatories such as ketorolac (Acular) and diclofenac (Voltaren) after surgery. (Topical steroids aren't as effective at blocking prostaglandins.)

What's Holding You Back?

Surgeons often use non-steroidals before cataract surgery to help keep the pupil dilated, to minimize other types of inflammation, and to keep the patient more comfortable when using topical anesthesia. Unfortunately, these uses don't seem to prevent postoperative edema. But many surgeons still hesitate to prescribe them following surgery.

One reason for this is that several years ago a small cluster of cataract patients developed corneal ulcerations as a result of using topical nonsteroidals following surgery. However, almost all of those cases were related to a generic diclofenac that was eventually pulled from the market. There have been only a handful of cases reported since then.

Also, some surgeons see macular edema as a relatively insignificant problem. If a patient has gone from 20/100 to 20/30, the surgeon may see no reason for concern -- and the patient may agree. (In fact, without macular edema the patient might see 20/20.)

Another issue has been patient complaints of burning or stinging during instillation of the drops. However, the newest formulation of ketorolac, Acular LS, appears to have minimized this problem. The manufacturer has been able to lower the concentration of ketorolac in the drop -- as well as the concentration of preservative -- and still maintain the same level of effectiveness. This has dramatically reduced patient complaints of discomfort.

An Ounce of Prevention . . .

Why not simply wait and treat macular edema if it occurs?

For one thing, you can't always reverse edema. Once the macula swells, topical nonsteroidals are effective about 90% of the time. That leaves 10% of patients with irreversible vision loss.

Also, you may never know that your patient has developed macular edema. It typically occurs 8 to 12 weeks after cataract surgery; most surgeons follow their patients for 4 to 6 weeks and then tell them to come back in a year. And patients who do notice a change may blame it on other existing problems.

Ensuring the Best Outcome

The prophylactic use of topical nonsteroidals is effective, safe, and could improve the vision of tens of thousands of patients. In addition, discomfort should no longer be an issue, thanks to Acular LS.

What protocol is most effective? Unfortunately, no studies have yet addressed this issue. I have my patients use the drop along with a steroid drop for 4 weeks: q.i.d. for 1 week, t.i.d. for 1 week, b.i.d. for 1 week, and once a day the final week. (I also start nonsteroidal drops 3 days before surgery, for the reasons mentioned earlier.)

I believe using nonsteroidal anti-inflammatories to prevent post-surgical macular edema is something all surgeons should consider.

Dr. Raizman is an ophthalmologist at Ophthalmic Consultants of Boston, associate professor of ophthalmology at Tufts University School of Medicine, and director of the Cornea and Anterior Segment Service at the New England Eye Center. He specializes in treatment of inflammation, laser vision correction and anterior segment surgery.