I POST OPERATIVE CARE BUSTER Snug Collars Each collar type suits a purpose Transparent collar vs. opaque collar The choice of a transparent or opaque collar depends on the animal’s condition and behavior. Transparent options provide a wider, yet reduced view. Some pets feel less confined and anxious if their vision is not as limited. For animals that seek den-like places when resting or seeking comfort, an opaque collar can offer a good solution. It offers the function of hiding the animal from any potential threat or distraction. A big thank you to Ethologists Tilde Detz-Jensen and Roberto Barata for sharing their knowledge and experience with us. Dog’s vision Dogs have much better vision in dim (weak) light than people. This is due to a reflective layer (tapetum lucidum) located behind the retina that reflects light back to hit the retina a second time. Vision in reduced light is also improved because the canine retina contains mostly rods that are more light-sensitive. In addition, many rods are connected to the same nerve fiber, which further increases light sensitivity, but decreases resolution. UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION Dogs probably do not see an equally sharp picture as humans and have a very limited depth BLI o ND f A v R i E s A ual acuity B . LI D ND o A g RE s A have the capability to see colour, particularly in the blue-violet and the yellow-green ranges. However, their retina contains relatively few colour-sensitive cones. They also have fewer colour-comparing neurons than humans. It h 60 a ˚ s therefor 6 e 0 b ˚ e 6 e 0 n ˚ suggeste 6 d 0˚ that aimlthpoourtgahntdtoogtshaerme .capable BIN o O f C s U e 6 LA 0 e R ˚ i V n IS g ION colou B r IN , O it CU m 6 LA 0 a R ˚ y VIS n IO o N t be BLIND AREA BLIND AREA BLIND AREA UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION 60˚ 60˚ 120˚ 120˚ 120˚ 120˚ BINOCU 6 LA 0 R ˚ VISION Av B e L r IN a D g A e RE D A og BINOCU 5 LA 0 R ˚ VISION BLIND AREA BINOCU 5 LA 0 R ˚ VISION B B o LI r N z D o A i REA UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION UNIOCULAR VISION 120˚ 120˚ 55˚ 110˚ 55˚55˚ 110˚ 55˚ BINOCU 5 LA 0 R ˚ VISION BINOCULAR VISION BINOCULAR VISION BLIND AREA Pekingese Vision field of the dog across breeds UNIOCULAR VISION UNIOCULAR VISION 55˚ 55˚ 110˚ BINOCULAR VISION Cat’s vision The cat’s eyes are adapted for hunting in low light and have superior low-light vision. This is due to a combination of the large lens, pupil, and cornea, the tapetum lucidum, and a large number of rods. The tapetum lucidum, a layer of reflective cells behind the retina, reflects light back through the eye, allowing for a second chance of absorption by the rods and cones. Cats have about three times more rods (important for low-light vision) than humans and only about a sixth of the number of cones (used for colour vision). The visual field of cats is around 200° with binocular vision in the 90-100° range, which is similar to humans (Bradshaw, 2013). Cats are adept at noticing motion, which is advantageous when hunting field mice or preying on other small animals. Because of the blurring caused by the tapetum lucidum and decreased resolution due to the increased number of rods, the cat’s visual acuity is limited. It has been determined that cats are able to see some colour. Most likely they have dichromatic vision, with sensitivity to greenish-yellow and blue. However, their ability to see a diversity of colours is limited. The domestic cat’s eye is not specialised for colour vision and the importance of colour is likely minimal for the species. The pupil of the cat can quickly constrict to a thin slit. This is to protect the light-sensitive BLIND AREA retina. This ability is common in nocturnal animals that also spend time in full sun. 30˚ 30˚ UNIOCULAR VISION UNIOCULAR VISION Vision field of the cat 140˚ BINOCULAR VISION www.kruuse.com KRUUSE© 04/2021 · 20885 INT
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