From the Guidelines
Children who are false positives when screened with the Spot Vision Screener tend to be younger (typically under 3 years old), have darker iris pigmentation, smaller pupil sizes, or poor fixation during testing, as noted in the most recent guidelines 1. These children may be incorrectly flagged as having vision problems when they actually have normal vision. False negatives, on the other hand, often occur in children with mild refractive errors that fall just below the screening threshold, intermittent strabismus that isn't present during screening, or subtle amblyopia. Children with accommodative esotropia may also be missed as they can temporarily compensate during brief screenings. The accuracy of the Spot Vision Screener varies with age, with higher false positive rates in very young children due to their developing visual systems and difficulty maintaining proper positioning and attention during screening, as highlighted in the pediatric eye evaluations preferred practice pattern 1. Environmental factors like poor lighting conditions or improper device positioning can also contribute to inaccurate results. When implementing vision screening programs using this device, it's essential to consider these characteristics and potentially adjust referral criteria based on age groups, with more conservative thresholds for younger children to reduce unnecessary referrals while still identifying those who truly need comprehensive eye examinations. Key factors to consider include:
- Age: Younger children (under 3 years old) are more likely to be false positives due to their developing visual systems and difficulty with screening tests 1.
- Iris pigmentation: Children with darker iris pigmentation may be more likely to be false positives due to the potential for inaccurate readings 1.
- Pupil size: Children with smaller pupil sizes may be more likely to be false positives due to the potential for inaccurate readings 1.
- Fixation during testing: Children with poor fixation during testing may be more likely to be false positives due to the potential for inaccurate readings 1. The most critical consideration is to ensure that vision screening programs are designed to minimize false positives and false negatives, while also providing timely and effective referrals for children who require comprehensive eye examinations, as emphasized in the latest guidelines 1.
From the Research
Characteristics of False Positives and False Negatives
- The Spot Vision Screener has demonstrated good sensitivity and specificity in detecting amblyogenic risk factors in pediatric populations 2, 3.
- False positives and false negatives can occur due to various factors, including the device's sensitivity and specificity, as well as the population being screened.
- In a study of children younger than 3 years, the Spot Vision Screener had a sensitivity of 89.8% and a specificity of 70.4% compared to a comprehensive eye examination 3.
- In another study of school-aged children, the Spot Vision Screener had a sensitivity of 89.5% and a specificity of 76.7% in detecting amblyopia risk factors 4.
Factors Contributing to False Positives and False Negatives
- The prevalence of amblyogenic risk factors in the population being screened can affect the number of false positives and false negatives.
- For example, in a study of underprivileged children, the Spot Vision Screener had a sensitivity of 82.35% and a specificity of 91.67% in detecting refractive errors 5.
- The device's threshold settings can also impact the number of false positives and false negatives, with optimized thresholds improving sensitivity in detecting refractive error 4.
- The age of the children being screened can also be a factor, with younger children potentially having higher rates of false positives and false negatives due to the challenges of screening this age group 3.
Comparison to Gold Standard Exams
- The Spot Vision Screener has been compared to gold standard exams, including cycloplegic retinoscopy and comprehensive eye examinations.
- In general, the Spot Vision Screener has demonstrated good sensitivity and specificity compared to these gold standard exams, although there can be variability depending on the population being screened and the device's threshold settings 2, 3, 5, 4.
- A study using noncycloplegic videorefraction and orthoptic examination as a screening method found a sensitivity of 0.67 and a specificity of 0.96 in detecting significant refractive error and strabismus in infants 6.