FRISBY NEAR STEREOTEST (3 Plates)

An easy-to-use screening and assessment test for stereopsis using natural vision, without the need for special glasses.  

This is a free-space, real depth stereotest consisting of three plates which permit stereoacuity measurements in the range of 600-5 seconds of arc. Each of the three plates has four random texture patterns, with a hidden circular shape in one. The patient has to decide in which pattern the hidden shape lies.

Suitable for a wide age range, especially shy pre-school children and pre-verbal babies from 7 months.

Test Uses:

• Used in the screening and detection of problems with stereoscopic vision in children, babies, the adults and elderly 
• Used world-wide in orthoptic and ophthalmology clinics and by optometrists and health care providers since 1975
• No special glasses needed 
• 3 plates of different thicknesses present differing sizes of disparity cues and allowing stereoacuity to be measured

Test Details:

The Frisby is the only stereotest that presents “real depth” objects viewed with natural vision.  No testing glasses are required, which means the tester can watch the patient's eyes and deduce preferential looking, particularly helpful when testing young children.

Each plate has four random-pattern squares with a circle of pattern elements lying in depth relative to its surround. The depth effect is due to the circle and its surround being printed on opposite sides of the plate.

The test has 3 plates of different thicknesses, providing stereoacuity measurements in the range 600-5 sec arc.  

The plates are stored in a box with a fold-down flap which provides a clear background used in the testing procedure.  A tape measure is provided for controlling eye-to-plate distance. 

The plate is shown 5-10 cm above the clear background and should not be laid flat against it.  The tape is is fixed to the flap for measuring and controlling eye-to-plate distance.

Unique Features:

The plates can be rotated or turned over to change the position of the circle to reduce false-positive responses.  It is the only stereotest that allows for repeat testing without the patient learning for the wrong reasons or by memory.  

Care should be taken to ensure the test plate and the patient's head stay still so as to ensure the test is administered correctly and no monocular cues are introduced.