Myopic shift rate decreases throughout childhood

Six-year data add insight into predicting eventual refractive error in children.

Issue: July 15, 2000

SAN DIEGO — Although IOLs in children have become more popular, it remains difficult to predict myopic shift at younger ages, as well as the eventual refractive error the child will ultimately have.

According to David A. Plager, MD, the controversies remain because of limited experience. One of these areas has to do with what power IOL should be implanted in a given child at a given age.

“There have been a number of previous recommendations along these lines including such things as using a single power lens,” in all patients, Dr. Plager said. “Others would advocate correcting the child for emmetropia at any age with the idea that this will facilitate amblyopia treatment.”

Some surgeons choose to undercorrect the children depending on their age, and Dr. Plager’s study used this strategy. He discussed his 6-year results at the American Association of Pediatric Ophthalmology and Strabismus meeting here.

5-year data

Dr. Plager studied children who underwent surgery between 1990 and 1995. There were 79 surgeries, 88% of which involved developmental cataracts and 12% that involved trauma. The majority of children saw very well, and the few that did not were limited by amblyopia.

Children underwent surgery between the ages of 2 and 15 years. The minimum follow-up was 4 years, and the average follow-up was slightly more than 6 years.

All children underwent the same surgical technique of a 6-mm corneal scleral incision, a capsulorrhexis by vitrectomy or by hand, and a 6-mm rigid IOL placed in the capsular bag. He has since abandoned this procedure in favor of a small, clear corneal incision and an AcrySof lens (Alcon, Fort Worth, Texas).

The 2- to 3-year-old children had an average change of 0.8 D per year for the next 6 years. By the time they reach ages 6 and 7, they have a mean 0.54 D refractive change per year, which fell to 0.17 D by ages 8 to 9.

By the time the children reached ages 10 to 15, they change only 0.1 D per year.

“There is not only a decrease in the amount of change per year, but also a decrease in the variability,” he said. “We can be a little better at predicting what they need in the older age groups.”

Large shifts seen

A couple of children had unusually large shifts and were considered outliers. Two eyes belonged to the same child, a 3-year-old boy implanted and predicted to have a +3.5 D refractive error. His actual error was +3 D in each eye. By age 10, his refractive errors were –7.25 D and –8.5 D. His axial length increased from 20 mm to 24 mm, which explains the myopic shift, Dr. Plager said.

Dr. Plager excluded glaucoma as a cause because of the child’s normal pressure and lack of disk changes.

A more likely explanation is heredity, he said. His mother has –6 D and a –3 D refractive errors, and his father has a –2 D refractive error bilaterally.

“My guess is this child was destined to be myopic and the pseudophakia probably had nothing to do with it,” Dr. Plager said. “Unfortunately, at this stage, we don’t have a very good way of predicting which children are going to inherit which genes from their parents. Perhaps that’s something someday we can toss into the mix.”

For Your Information:

David A. Plager, MD, can be reached at the Indiana University Medical Center, Department of Ophthalmology, 702 Rotary Circle, Indianapolis, IN 46202; (317) 274-8103; fax: (317) 274-1111. Dr. Plager has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.