From the Research
Over-referral by Spot in children with normal visual acuity (VA) and no treatable amblyopia risk factors (ARF) typically occurs due to several specific conditions, including refractive errors, mild anisometropia, physiologic astigmatism, and pseudostrabismus, as well as technical limitations of the Spot device and standardized referral criteria that don't account for age-specific normal variations in visual development. The primary causes of over-referral include:
- Refractive errors that fall just outside normal parameters but are not clinically significant
- Mild anisometropia (difference in refractive power between eyes) that doesn't impact vision
- Physiologic astigmatism that resolves naturally with age
- Pseudostrabismus where eye alignment appears abnormal but is actually normal Other contributing factors include:
- Inconsistent test results due to poor child cooperation during screening
- Environmental factors like inadequate lighting or distractions during testing
- Technical limitations of the Spot device itself, which may have higher sensitivity at the expense of specificity According to the most recent study 1, amblyopia is a visual deficit that occurs during childhood and results in an abnormal development of the normal cortical visual pathway, and early detection of amblyogenic factors is important. Additionally, the use of standardized referral criteria that don't account for age-specific normal variations in visual development can lead to unnecessary referrals, as noted in 2. These false positives occur because the screening technology is designed to err on the side of caution, prioritizing the detection of all potential vision problems even if it means some children without significant issues are referred for comprehensive examination. Understanding these factors can help clinicians better interpret Spot screening results and potentially adjust referral thresholds to reduce unnecessary specialist visits while still identifying children who truly need intervention, as suggested in 3.