WHITE-RED-BLUE TEST - INFORMATION
THE ESSENCE OF THE METHOD
Method for determining the functional activity of the retina when stimulated by light of different wavelengths WHITE-RED-BLUE (Chromatic Pupillary Light Reflex) consists in evaluating the pupillary reflex when the retina is stimulated by red and blue light of a strictly defined wavelength.
During the test, the researcher evaluates:
The speed of pupil contraction (fast, slow, absent);
The amplitude of the pupil contraction (complete, incomplete, absent).
The essence of the method is that RED light maximally stimulates the reaction of the photoreceptor layer of the retina (rods and cones), which is responsible for image perception, i.e. directly for visual functions, while BLUE light causes the maximum reaction of the so-called melanopsin-containing retinal ganglion cells.
In healthy animals (without retinal abnormalities), the speed and amplitude of pupil contraction when stimulated by RED and BLUE light are almost the same.
Depending on the degree of damage to the photoreceptor layer of the retina, the RED light reflex slows down (to complete absence), and the BLUE light reflex remains unchanged (until the top layer of the retina – the layer of melanopsin-containing ganglion cells – is damaged).
In severe or long-term retinal lesions accompanied by its structural destruction (detachment, hemorrhage, severe degenerative lesions, large-scale chorioretinitis, severe congenital abnormalities, etc.), the reflex to BLUE light is also suppressed (to the point of complete absence).
WHITE light is necessary for a preliminary assessment of the condition of the studied eye and the presence of the pupillary reflex, as such, as well as to exclude gross eye pathologies.
ADVANTAGES
The WHITE-RED-BLUE test is easy to perform, non-contact, painless, and highly informative. Assessment of retinal functions can be performed in animals with significant opacity of the optical structures of the eye (corneal edema, cataract, glaucoma, vitreous degeneration). The test can be performed in animals of any type (dogs, cats, rodents, ferrets, birds, monkeys, horses, etc.) and age (from newborns to old animals).
The test can be performed in wild or aggressive animals through the bars of the cage.
