ILM removal safe, effective for refractive macular edema

Internal limiting membrane (ILM) removal is a safe, effective way to treat refractive macular edema, according to Ferenc P. Kuhn, MD, PhD, University of Alabama at Birmingham, United States.

The rate of recurrence is low, and it can be used as a first-line treatment, he added. Lack of traction preoperatively should not be considered a contraindication, and the earlier the surgery is performed, the better.

"Diabetic macular edema is the number one cause of blindness in diabetics, and the number of people with this disease is going to double in 20 years," Dr. Kuhn said.

Treatment options include observation, laser, steroid injections, surgery, and anti-VEGF therapy.

Dr. Kuhn focused his talk on all but the latter option. Anti-VEGF "is a very simple procedure, but there is a huge cost associated with it, and we don't know exactly the indications and dosage, and there are a lot of legal issues," he said.

Regarding laser treatment, he said, the improvement rate remains low, and the treatment is most effective as a way to conserve the condition of the eye rather than improve it.

The intravitreal use of triamcinolone results in rapid improvement in the eye, Dr. Kuhn said, but the benefit usually is short-term, and additional injections often are needed. Also, the best dosage is not clear, and use of the drug can elevate IOP.

Vitrectomy can achieve fairly good improvement, he said, but a second surgical treatment option is to remove the ILM. Doing so increases oxygenation and eliminates traction.

Dr. Kuhn and colleagues studied 68 consecutive eyes of 61 patients who had cystoid macular edema of any origin, previously treated or untreated. Patients were excluded if they'd had vitreous hemorrhage, macular detachment, or would not be available for follow-up.

Most of the patients were male and of young age. "All of these patients had some systemic component," he said.

Dr. Kuhn said it's important to stain the ILM after vitreous removal because it not only helps to locate the ILM but "it is also a lot more traumatic" to the retina otherwise.

"The vast majority of patients showed improvement" after ILM removal, he said of the study on which he reported, "but it took an average of 4 months for the improvement to achieve its maximum extent."

Regarding functional results, Dr. Kuhn said that 70% of ILM removal patients showed an improvement of at least 2 lines (with an average of 5 lines) compared with 3% for laser treatment. Recurrence was noted in 2% of ILM removal patients, compared with 60% of laser-treated patients. The most important complication was cataract, he said.

All eyes with a preoperative visual acuity of 20/30 improved to 20/20 postoperatively, Dr. Kuhn said, stressing the ideal to perform ILM removal as soon as possible.

The number of eyes in which vision deceased was about the same with either ILM removal or laser treatment, he said.