Related Experiment Video
Updated: Aug 2, 2026
Testing Sensory and Multisensory Function in Children with Autism Spectrum Disorder
Published on: April 22, 2015
Frisby Davis distance stereoacuity values in visually normal children
W E Adams1, S Hrisos, S Richardson
1Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK. wendy_stoer@yahoo.com
Insights
The Frisby Davis distance stereo test (FD2) measures distance stereoacuity in young children. Normal values show improvement with age, providing a baseline for clinical comparisons.
Area of Science:
- Ophthalmology
- Pediatric Vision
- Stereopsis Measurement
Background:
- Assessing distance stereoacuity in young children is crucial for early detection of visual impairments.
- The Frisby Davis distance stereo test (FD2) is a tool used for evaluating stereopsis.
Purpose of the Study:
- To establish the normal range of distance stereoacuity in children aged 36 to 68 months using the FD2.
- To investigate the relationship between age and distance stereoacuity in this cohort.
Main Methods:
- A standard testing protocol was used to measure distance stereoacuity with the FD2 in visually normal children.
- Participants were children aged 36–68 months who passed preschool vision screening.
Main Results:
- Out of 59 children, 6.8% had no measurable stereoacuity, and 24% had stereoacuity only at 3 meters.
- The remaining 76% demonstrated stereoacuity at 6 meters, with significantly better results in older children (mean 29.6 arc seconds vs. 92.3 arc seconds).
Conclusions:
- The FD2 is effective for measuring distance stereoacuity in young children.
- Distance stereoacuity shows a maturational improvement between 36 and 68 months of age.
- The study provides age-related normative data for clinical use.
Aims:
To establish the range of normal distance stereoacuity in young children using the Frisby Davis distance stereo test (FD2).
Methods:
Children passing preschool vision screening assessments underwent measurement of distance stereoacuity with the FD2 using a standard testing protocol.
Results:
59 visually normal children aged between 36 months and 68 months were recruited to this study. All 59 were able to understand the test requirements and were examined with the FD2 stereo test. Four (6.8%) had no measurable stereoacuity; 13 (24%) had stereoacuity measurable only at a 3 metre testing distance (mean 92.3 seconds of arc; SD 52.6). These children were significantly younger than the remaining 42 (76%) who demonstrated a stereoacuity response at a 6 metre testing distance (mean 29.6 seconds of arc; SD 13.1, p=0.008).
Conclusion:
The FD2 stereo test enables the measurement of distance stereoacuity in young children. There appears to be a maturational effect with distance stereoacuity improving between 36 months and 68 months. The data on age related normal values will provide a baseline from which to compare outcomes in clinical populations.
