Test Finds Visual Field Defects in Very Young Children

By Anne Harding

January 07, 2015

NEW YORK (Reuters Health) - A test developed by Dutch researchers can detect peripheral visual field defects in children who are too young or neurologically impaired to perform standard conventional perimetry (SCP), according to a large retrospective study.

SCP requires that patient to cooperate, and "even the simpler versions . . . are often unsuccessful in children younger than six years," Dr. Yvonne Koenraads of University Medical Center Utrecht in The Netherlands and her colleagues wrote online December 26 in JAMA Ophthalmology.

In 1995, to address the problem, Dr. Koenraads and her team developed the Behavioral Visual Field (BEFIE) Screening Test, which consists of a graded semicircular arc upon which a visual stimulus is introduced, from behind the child's visual field, from the periphery to the center. An observer records when the test subject responds visually or verbally to the stimulus.

Recognizing visual field defects is important, Dr. Koenraads told Reuters Health, because it can prevent delays in diagnosis of diseases such as craniopharyngioma and optic pathway glioma. "In addition, it is helpful in the early diagnosis of hemianopias and quadrantanopias, of which parents should be aware in order to have a correct interpretation of the child's behavior," the researcher said via email.

"In our center this method is also extensively used to identify whether such a visual field defect does or does not already exist before epilepsy surgery is performed. This type of neurosurgery, which may cause a visual field defect, has an important role in treatment of refractory epilepsy," she added.

For the new study, Dr. Koenraads and her team reviewed records of all children who underwent the test at their center. Out of 1,788 tests in 835 children, 74% were considered reliable, 14% were "doubtful," and 12% were unsuccessful.

The older the child, the more reliable the test. It was 56% reliable in children younger than one year, 71% in children ages 1 to 2, and 75% in children older than 2. The median age of children taking the test was 3.4 years.

Along with the retrospective design, limitations of the study include the fact that the pediatric neuro-ophthalmologist who performed the tests knew a child's clinical background, and the assessor who gauged the reliability of the tests was not blinded.

Still, the authors say, "the test proved to aid in the determination of PVF (peripheral visual field) defects in a clinical setting from the age of 4 months onwards . . . These PVF defects would otherwise have remained unnoticed because there was no alternative in children who were not able to perform SCP."

Currently, Dr. Koenraads added, the BEFIE test is being used at her center, at some medical centers in Italy, and another site in the Netherlands. "Oral presentations that we gave at several conferences last year gave rise to enthusiastic responses on this device. Therefore we assume the instrument has great potential."

Her team is presently investigating whether diffusion tensor imaging-based tractography of the optic radiation may predict visual field defects identified with the BEFIE test.

The study had no outside funding.

SOURCE: http://bit.ly/1xOGf2e

JAMA Ophthalmol 2014


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