June 2008

 

OPHTHALMOLOGY NEWS

 

Ametropic preschoolers’ ability to learn


by Maxine Lipner Senior EyeWorld Contributing Editor

 

 

Possible window of cognitive opportunity for hyperopic children

Children with ametropia showed dramatic improvement on cognitive tests with six weeks of spectacle use Source: Stuart I. Brown, M.D.

Uncorrected hyperopic ametropia lowers preschoolers’ scores on tests reflective of their learning abilities according to recent study results published in the February 2008 issue of Archives of Ophthalmology. However, after just six weeks of wearing spectacles these children had recovered important ground, according to Stuart I. Brown, M.D., chairman, department of ophthalmology, and director, Shiley Eye Center, University of California, San Diego.

In the study, investigators considered the cognitive abilities of 70 preschoolers from low income backgrounds. Dr. Brown and fellow investigators undertook the study spurred by the idea that refractive difficulties might be leading to cognitive problems. “The impetus here was the sense that children with refractive errors might not want to do things up close where learning is required,” Dr. Brown said.

Examining ametropic preschoolers

Those included in the study were children between the ages of three and five who were enrolled in public preschools for low income children, according to Barbara Brody, M.P.H., clinical professor, department of ophthalmology and director of the division of community ophthalmology, University of California, San Diego. All of the 35 ametropic children had refractive errors with hyperopia and astigmatism at a level significant enough to warrant glasses. Ametropia for these three- to five-year-old children was defined as bilateral hyperopia of 4.00 D, with astigmatism of 2.00 D or more for the three-year-old children and 1.50 D or more for the older children.

These ametropic children were matched with a group of 35 controls with normal vision. “The control group was matched from the same schools,” Ms. Brody said. “These were children who were also examined and found not to have any refractive error.”

All of the children received comprehensive eye examinations in a mobile eye clinic under cycloplegia. “We tested their vision before correction and prior to cycloplegia,” Ms. Brody said. “Then we prescribed glasses correcting the full astigmatic error and slightly under-correcting the hyperopic refractive error, as is the standard of care.”

Before receiving their glasses, those included underwent rigorous developmental testing. “The children were tested one-on-one by skilled psychometrists using two standardized, widely used tests that are considered to be predictive of future learning ability,” Ms. Brody said. The two tests used were the Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R). On both of these tests the ametropic children initially had significantly lower scores than the visually normal control group. “We found that compared to the controls they had reduced scores on both of these tests,” Ms. Brody said. These children were found to be significantly behind, Dr. Brown said. “They had scores that were comparable to kids who were affected by nutritional deficiencies, high blood concentrations and low birth weight and prematurity,” he said.

The children were then given their glasses and told to wear them for the next six weeks. When the children were brought in again at six weeks, investigators found that their scores had improved on both tests. “The children who needed the glasses came up to the level of the controls on the test for visual motor integration,” Ms. Brody said. “Six weeks of wearing the glasses brought them into the normal range on that test.”

When it came to the WPPSI-R results some improvement was also seen, although not to the level found on the VMI. “The results on the WPPSI-R performance also improved, but the amount of change between the children who needed the glasses and their controls had not reached statistical significance at six weeks,” Ms. Brody said. Investigators theorize that more time wearing the glasses may be needed here.

Implications for learning

The ramifications of these results are far reaching. “What it would suggest is that these ametropic children are at risk because the tests used are highly predictive and correlate well with successful school learning,” Ms. Brody said. “The need for correction of their ametropia is apparent.” Early intervention may be key in these children, believes Dr. Brown. “Our goals are to see how long it really takes for complete recovery and whether, as with amblyopia for instance, it takes more time with each year of age that passes for children to recover their vision until it is finally very difficult,” Dr. Brown said. “I believe that there is going to be a developmental window that we will find.”

Going forward, Dr. Brown stresses the importance of screening for ametropia. “Every minute that goes by the child loses,” Dr. Brown said. “In amblyopia it’s just the recovery of sight (in question), but in this instance it’s the concept of learning.” He worries that if the child’s ability to learn is compromised by vision for long enough, he or she may permanently suffer. “The child may catch up on these cognitive tests but never (truly) catch up. That would be a shame,” he said. “This tells me that children should get screened, and there are no schools of thought here—there should be a process in place for this because this is our future.”

Editors’ note: Dr. Brown and Ms. Brody have no financial interests related to their comments.

Contact

Brody: 858-822-2831, bbrody@ucsd.edu

Brown: 858-534-8823, sbrown@eyecenter.ucsd.edu

Ametropic preschoolers’ ability to learn Ametropic preschoolers’ ability to learn
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