Frequently Asked Questions
What is stereopsis, and why is it important?
Stereopsis is the ability to perceive depth and three-dimensional structure from binocular visual input. It plays a crucial role in hand-eye coordination, spatial awareness, and daily activities like sports, reading and even driving and moving around spaces. Without stereopsis, depth perception is significantly reduced, which can impact learning, mobility, and performance in various tasks.
How does the Frisby Stereotest work?
The Frisby Stereotest presents real-depth targets using transparent plates with random-dot patterns. Unlike tests that require special glasses, the Frisby test uses natural depth perception cues, making it ideal for infants, young children, and those with language barriers. Patients identify the target without needing red-green or polarized lenses, ensuring a more natural and engaging testing experience.
Who should be tested for stereovision?
Stereopsis testing is beneficial for:
- Children and infants, to help detect early visual development issues like strabismus or amblyopia
- Adults and teenagers, particularly those struggling with depth perception, sports performance, or previous eye conditions.
- Elderly patients, as stereopsis can decline with age or due to eye conditions like cataracts.
- Individuals in professions requiring precise depth perception, such as pilots, surgeons, or athletes.
What makes the Frisby Stereotest different from other stereotests?
Unlike many stereotests that rely on 3D glasses, the Frisby Stereotest uses real-depth cues, avoiding issues like binocular dissociation, lens-induced distortion, or patient reluctance to wear special glasses. This makes it particularly effective for young children, non-verbal patients, and those with fragile binocular vision.
Can the Frisby Stereotest be used to monitor vision therapy progress?
Yes! The Frisby Stereotest is often used in vision therapy and rehabilitation to track improvements in stereovision. Since it provides graded levels of difficulty, it allows practitioners to monitor subtle changes in binocular function over time.
Does the Frisby Stereotest give monocular clues?
No. A common misconception is that the Frisby Stereotest provides monocular depth cues. This belief stems from early misinterpretations where the test was presented incorrectly—laid flat on a table instead of held at the correct distance from the background. Indeed images of this incorrect presentation were shared on the internet and via some research papers. When used properly, the Frisby test is a highly accurate stereopsis assessment tool free from monocular cues.
Can the Frisby Stereotest be used for repeated testing?
Yes. The Frisby Stereotest allows for repeat testing without the risk of memorisation or learning effects, as it does not rely on familiar shapes or objects. This makes it highly reliable for ongoing patient assessments and longitudinal studies of stereovision. This is a unique feature of the Frisby Stereotest compared to other stereotests.
Is the Frisby Stereotest suitable for adults?
Absolutely. While widely used for pediatric vision screening, the Frisby Stereotest is also valuable for adult patients, including those undergoing vision therapy, experiencing changes in depth perception, or requiring occupational assessments for careers that depend on precise stereopsis.
How does poor stereopsis affect everyday life?
Individuals with reduced stereovision may struggle with any of the following - and may have found adaptations to overcome the challenges they present:
- Judging distances, such as when driving or walking down stairs
- Hand-eye coordination, making tasks like pouring liquids or catching objects more difficult
- Reading and learning difficulties, particularly in young children
- Performance in sports, where depth perception is essential for timing and spatial awareness
Where can I purchase the Frisby Stereotest?
The Frisby Stereotest is available through authorised distributors and directly from us. If you’re interested in purchasing or becoming a distributor, please get in touch via our Contact page.
