3D Depth Perception Insights for Optometrists
Confidently assess stereovision in every child.
Stereoacuity testing provides valuable insight into how a child’s eyes are working together. The Frisby Stereotest makes this assessment quick, practical, and easy to include in routine sight tests, supporting decisions to reassure, monitor, or refer when appropriate.
Why Stereoacuity Assessment Matters
Assessing stereovision forms an important part of paediatric eye examinations and supports assessment of binocular vision and depth perception. Stereotests can provide reassurance when results are within normal limits, while helping to identify when further investigation may be required.
While optometrists (also known as opticians in the UK) primarily focus on vision correction and eye health, evaluating stereopsis is valuable when investigating visual efficiency, coordination, and how the eyes work together — particularly when patients report symptoms such as double vision, poor hand–eye coordination, or difficulties with depth judgement.
In paediatric eye care, early assessment of stereovision can support timely identification of reduced binocular vision, and progression or referral to orthoptic services when appropriate. Incorporating stereoacuity assessment into routine sight tests helps optometrists gain confidence in their clinical judgement without extending examination time, while supporting children’s visual development and learning in the early years.
“Assess stereopsis. Having good stereopsis may indicate the child does not have significant anisometropia, amblyopia or squint.”
— College of Optometrists, Paediatric Eye Examination Guidance
Designed for the realities of busy Optometry practice
Optometrists are working within time-limited appointments, and patients — especially young children — may struggle with complex or abstract tests. In everyday practice, optometrists need assessment tools that are quick to administer, easy for children to engage with, and above all, reliable and well trusted.
The Frisby Stereotest was designed specifically to meet these needs, allowing stereoacuity assessment to fit naturally into routine sight tests without additional equipment, glasses, or complex set-up.
So why choose the Frisby Stereotest?
1. Clinically robust assessment of true stereopsis
A random dot test using real depth
The Frisby Stereotest is a random dot stereotest, meaning the test figure shares the same random dot pattern as the background. Random dot tests are widely used to assess precise stereopsis, which is particularly relevant for fine motor skills and everyday depth judgement.
Unlike image-based stereotests that simulate depth, Frisby presents real, physical depth using objects in free space. This supports assessment of true stereopsis under natural viewing conditions.
Reliable responses and repeatable testing
Frisby avoids reliance on memorisable images or embedded shapes. Because the test uses real 3D depth created by different plate thicknesses, it allows:
- preliminary ‘training’ or demonstration trials to confirm task understanding
- repeat testing without the patient learning how to pass by memory or familiarity
Built-in precautions to avoid monocular cues
When presented correctly, Frisby has been shown to have the least susceptibility to monocular cues compared with other commonly used near stereotests (Holmes, J. M. & Leske, D.A., 1999).
2. Practical in high-street settings
Viewed with natural vision
No stereograms or special glasses are required. Testing is carried out using the patient’s natural vision, which can be particularly advantageous for:
- young children and babies
- spectacle wearers
- patients who may refuse or be distracted by red–green or polarised glasses
Removing additional glasses can also help avoid dissociation in patients with fragile binocular single vision, supporting more representative results.
With no additional equipment required, the test is quick and simple to administer, as well as easy for clinicians to learn and for patients to understand, allowing the assessment to fit comfortably within routine sight tests.
3. Supports confident decision-making
Child-friendly and inclusive
An engaging, game-like task that children quickly grasp.
Suitable for a wide range of ages, including young or pre-verbal children using preferential looking methods.
Appropriate for patients who may struggle with abstract or image-based tests.
Supports clinical judgement
Helps optometrists assess binocular vision with confidence.
Supports early identification of reduced stereovision.
Aids decisions to reassure, monitor, or refer when appropriate, complementing acuity and cover testing.
👉To find out more about what sets Frisby apart, visit our Unique Features page
