Data show ROP benefits from early therapy

San Francisco-Early treatment at high-risk threshold reduces the rate of unfavorable acuity and structural outcomes in infants with retinopathy of prematurity (ROP), according to William V. Good, MD. Reporting new findings from the Early Treatment for Retinopathy of Prematurity Study (ETROP), Dr. Good added that systemic side effects are more common with earlier treatment but can be managed in the nursery.

Other key conclusions from ETROP are that type 1 and type 2 algorithms help identify eyes that would benefit from earlier treatment and reduce treatment to eyes that may regress. The finding of Plus disease has become an even more important finding, said Dr. Good, senior scientist, Smith-Kettlewell Eye Research Institute, San Francisco.

The first results of the ETROP study were published in 2003. With grading acuity as the primary outcome measure, the results indicated that there was a highly significant reduction in unfavorable visual acuity outcomes from 19.8% to 14.3%. There also was reduction in unfavorable structural outcomes from 15.6% to 9%.

"We found no difference in ophthalmic complications between the eyes treated earlier and the conventionally managed eyes," he said. "On the other hand, systemic complications were about twice as frequent. These included apnea, bradycardia, arrhythmia, asystole-all of the things that make your stomach turn when you're taking care of these babies. Fortunately, we know of no known lasting significant systemic complications."

Prevalence of myopia

A recent paper analyzed the prevalence of myopia among infants in the ETROP study. It compared myopia and high myopia in earlier versus conventionally managed eyes in infants at 9 months post-term.

"The prevalence of myopia was not different, nor was high myopia different between eyes that were treated at high-risk prethreshold versus eyes that were managed conventionally," Dr. Good said. "You can also see that myopia has not gone away. It's still very common, although this analysis of myopia occurred in the particularly high-risk infants that were randomly assigned to this study.

"Also, myopia in ROP continues, as we noted in the CRYO-ROP study, to follow the structural findings in ROP. Abnormal angle of temporal vessels is associated with much more myopia. If there's no retinal residual following successful treatment for ROP, we still see myopia occurring in around 60% or so," Dr. Good said.

The conclusion from these findings is that earlier treatment at high-risk prethreshold does not place eyes at greater risk of myopia and high myopia than did conventional management, when myopia is measured at 9 months corrected age. And among conventionally managed high-risk prethreshold eyes, eyes receiving treatment at threshold ROP were more likely to have myopia or high myopia than those high-risk eyes that regressed without treatment, he continued.

Possible overtreatment

He also addressed growing concern about overtreatment: "Are we treating too many infants with ROP that would have regressed without needing particular surgical management? If one adheres strictly to the prethreshold criteria for treatment, there will be a certain amount of overtreatment of eyes."

In response, the ETROP study group developed an approach based on the International Classification for Retinopathy of Prematurity, which seems to be more suitable in clinical settings, he said.

"It allows a diagnosis of ROP that needs treatment based on clinical findings, not based on the 10 factors that were used originally to compute the risk of an adverse outcome," Dr. Good added.

"The additional analysis supports prompt retinal ablation for some types of eyes and observation for others. These are now the so-called type 1 and type 2 eyes," he said. "This approach significantly reduces treatment to eyes that may have had disease regression."