During the FPT test, each eye is covered and then uncovered. The doctor or technician may hold a small object or picture in front of the child. As one eye is covered, the doctor evaluates how well the uncovered eye maintains fixation. The test results give the doctor an idea of which eye sees better, if there is a difference between the two.
Besides looking for big differences in vision between the eyes, doctors are also looking for any decrease in vision due to amblyopia ("lazy eye") that may be caused by nearsightedness, farsightedness or large amounts of astigmatism.
For years, doctors considered FPT to be a quick, reliable method of evaluating a child’s vision. However, researchers at John Hopkins University have discovered that the FPT may not be as reliable as once thought. In a report published in the October 2008 issue of Ophthalmology, it was stated that current methods need to be re-assessed. For the study, visual acuity was evaluated in 1,504 children aged 30 to 71 months. The researchers used a series of tests including FPT and the Amblyopia Treatment Study. (The Amblyopia Treatment Study was conducted to determine whether atropine was as effective as patching for treating amblyopia in children less than seven years of age.) The study showed that when testing young children who could perform both tests, the FPT did not accurately identify problems in children’s vision when compared to the Amblopia Treatment Study.
These findings are significant because the FPT is considered the standard of care for testing vision in this age group. "Current methods of testing vision in very young children need to be reassessed," said lead researcher Dr. David S. Friedman, an associate professor of ophthalmology at John Hopkins University.
What Parents Need to Know
The FPT is really the only tool available to many eye specialists for evaluating children's vision. While the percentage of vision problems in preschool children is low, they do occur. The earlier the diagnosis, the better chance at success when treatment is given. While pediatric and school vision screenings do a wonderful job of catching some significant problems, it is not a bad idea to have a comprehensive eye and vision examination at around 3 to 4 years of age to at least serve as a baseline for future reference.Source:
Gever, John, Standard Lazy-Eye Exam Viewed as Undependable. MedPage Today, 2 Oct 2008.
