RETINOPATHY OF PREMATURITY
A Fresh Outlook On Stage 4A ROP
This diagnosis gives us a new opportunity to provide good vision.
By Michael T. Trese, MD
Finding a 4A retinal detachment in retinopathy of prematurity (ROP) used to predict an upsetting decline. But with appropriate intervention, it now represents a chance to reverse the process and preserve good vision.
GETTING THE TIMING RIGHT
The management of 4A retinal detachments involves:
1. Timing of intervention
2. Goals of intervention
3. Type of intervention
4. Surgical technique.
The timing of the intervention is essential as we must think in terms of postmenstrual age (the gestational age plus the weeks after birth, with the due date being 40 weeks postmenstrual age).
For threshold ROP, the peak incidence is at about 37 weeks postmenstrual age, and the range is from about 32 to 46 weeks. Acute retinal detachment from ROP tends to occur from about 38 weeks to about 50 weeks postmenstrual age, with a peak incidence at about 41 weeks. If a child does not develop a retinal detachment by 10 weeks after the due date, the likelihood that it will happen from acute ROP is very small.
For stage 4A ROP, lens-sparing vitrectomy has become the procedure of choice. We've reported an anatomic success rate of about
CHOOSING AN INTERVENTION
For a 4A retinal detachment, our goal is to stop progression to stage 4B or 5. The best result I can achieve for 4B and 5 is 76% anatomic success (some or all of the retina attached). The best visual acuities are 48% between 20/60 and 20/1900; 72% from 20/60 to light perception; and 28% no light perception.
One type of intervention is a scleral buckle, but we rarely do these anymore. They have an anatomic success rate of about 70%, and the visual results are poor. Other disadvantages are that it involves two operations, and we can induce up to 12 diopters of myopia with a scleral buckle in a baby.
For stage 4A ROP, lens-sparing vitrectomy has become the procedure of choice because it involves only one operation, which deals directly with traction. We've reported an anatomic success rate of about 90%. Two other current reviews1,2 in the literature show success rates of 89% and 94%, respectively.
OUTCOMES OF LENS-SPARING VITRECTOMY
My colleagues and I3 wanted to find out more about the resulting visual function, so we performed lens-sparing vitrectomies on children with 4A ROP in 12 sectors at 39 weeks postmenstrual age. In 14 children, the second eye was stage 5, meaning the chance of proceeding from stage 4A to stage 5 was about 85%.
Our surgical technique for two-port, lens-sparing vitrectomy included using the binocular indirect ophthalmomicroscope system to do the core vitrectomy. We addressed the division of the attachments that went from the ridge to the lens and the ridge toward the ora serrata. Next, for the dissection along the ridge, we used a high-magnification infusion contact lens.
We found that in stage 4A ROP, if the retina is attached, the average vision after lens-sparing vitrectomy was 20/55. If two children with severe central nervous system involvement were factored out, the average visual acuity would be 20/40. Some children are even at 20/20 today.
Finding the best intervention isn't the only step in saving the vision of children with stage 4A ROP. But with appropriate screening and laser and vitrectomy intervention, 4A detachments have a very good chance of good visual outcomes.
Dr. Trese is a clinical professor of biomedical sciences at the Eye Research Institute, Oakland University, Rochester, Mich., and a clinical associate professor at Kresge Eye Institute, Wayne State University, Detroit. He is chief of pediatric and adult vitreoretinal surgery at William Beaumont Hospital in Royal Oak, Mich.
1. Ferrone PJ, Harrison C, Trese MT. Lens clarity after lens-sparing vitrectomy in a pediatric population. Ophthalmology. 1997;104:273-278.
2. Hubbard GB, Cherwick H, Burian G. Ophthalmology. In press.
3. Prenner JL, Capone A Jr, Trese MT. Ophthalmology. In press.