Enzyme-assisted vitrectomy

November 15, 2007

Both anatomic and visual successes are possible when performing plasmin enzyme-assisted vitrectomy for primary and reoperated eyes with stage 5 retinopathy of prematurity. A review of cases performed over a 10-year period showed that about 70% of eyes had light perception vision or better, and nearly as many had successful reattachment.

Key Points

In a retrospective case study of 80 eyes with stage-5 ROP that underwent plasmin enzyme-assisted vitreous surgery, light perception or better was achieved in 70% of eyes; pattern recognition was achieved in 7.5%. Successful reattachment occurred in nearly 70%, also.

"It's pretty clear now that retinal detachment in ROP is best managed by early vitrectomy, with anatomic results from several studies now showing a 90% attachment rate and, from the study we did, an average vision of 20/50," Dr. Trese said. "But there are still some eyes that go on to stage 5. They exist both outside the United States and inside the United States, and there are those that progress after 4A surgery. The question comes, is it worthwhile to put people with those types of eyes through surgery?"

The infants in this series had a mean gestational age of 25.8 weeks and a mean birth weight of 1.73 pounds. Retinal detachment configuration was severe in many of the eyes, with the funnel closed posteriorly in about 82%. Considerable variation occurred in the timing of APE surgery. Plasmin enzyme-assisted vitrectomy was performed at around 1 year in groups 1 and 2 (at a mean of 52.5 and 62.7 weeks, respectively) and much earlier, at a mean of 32.2 and 30.1 weeks, respectively, in groups 3 and 4. Prior to surgery, all eyes had clinical light perception or a positive visual evoked potential.

Dr. Trese and Antonio Capone Jr., MD, also a member of Associated Retinal Consultants, Royal Oak, MI, performed all of the surgeries using a vitrectomy/lensectomy technique. Plasmin was used if space allowed and if the eye could not be repaired by standard surgery. It was placed in the vitreous cavity after removing the lens, if the lens was still present. The standard operation was performed after a 30-minute wait for the enzyme to work.

Visual outcomes

The overall reattachment rate in the four groups was 68.8%. Group 1 had an attachment rate of 78.9% (38 eyes), group 2 of 53.4% (15 eyes), group 3 of 65% (20 eyes), and group 4 of 57% (seven eyes). Partial attachments occurred in 13.2% of eyes in group 1, 13.3% in group 2, 20% in group 3, and none in group 4. Total detachment was reported in 7.9% of eyes in group 1, 33.3% in group 2, 15% in group 3, and 43% in group 4.