Amblyopia screening guidelines updated

By Joanna Lyford, Senior medwireNews Reporter

The American Association for Pediatric Ophthalmology and Strabismus (AAPOS), the professional body for pediatric eye care, has issued revised guidelines for preschool vision screening based on new evidence.

The guidelines, which were developed by the Vision Screening Committee of the AAPOS, include new age-specific diagnostic thresholds for amblyopia and an endorsement of photoscreening modalities for the detection of amblyopia risk factors.

The Committee chair, Sean Donahue (Vanderbilt University Medical Center, Nashville, Tennessee, USA), remarked: "Over the last decade, automated methods for vision screening have progressed to the point where they are now extremely effective in identifying vision problems in children prior to their being able to read an eye chart. It is exciting to see pediatricians adopt these technologies."

The first guidelines for automated preschool vision screening were published in 2003 and primarily addressed the magnitude of refractive error that was thought to put a child at risk for the development of amblyopia.

Since then, it has become apparent that the prevalence of amblyopia risk factors is much higher than previously thought and that the majority of children with risk factors do not develop amblyopia. Furthermore, new screening instruments have been developed that detect abnormalities other than amblyopia risk factors.

"If the detection of decreased vision and amblyopia are the goals of screening, then referrals based on technology that detects risk factors will result in overreferrals," explain Donahue and co-authors in the Journal of the American Association for Pediatric Ophthalmology and Strabismus.

"It is therefore imperative that updated guidelines for detecting amblyopia risk factors propose levels that best separate those children who are most at risk for developing amblyopia from those who are not."

To address these issues, the revised guideline includes four age-specific target refractive magnitudes for detection (12-30 months, 31-48 months, 49-72 months, and >72 months). It also recommends that the traditional optotype recognition screening option remains "a viable option for schoolage children who can read linear letters," and notes that stereopsis testing in isolation is poorly validated.

It states that new screening techniques that can detect children with amblyopia or strabismus directly "would be a major advance;" any such instrument should report sensitivity and specificity to detect manifest (not intermittent) strabismus, visual acuity <20/30, and three or more lines of interocular acuity difference.

The guideline authors conclude: "Further advances in technology will invariably force a reassessment of the preferred means of detecting children who have amblyopia or other causes of decreased visual acuity. Similarly, advances in our knowledge regarding the natural history of refractive error in children, and risk factors for amblyopia development will also force a reassessment of these guidelines.

"We actively encourage continued research in these areas and look forward to further revision of these guidelines."

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