A forced‐choice preferential looking task for the assessment of vision in dogs: pilot study

Abstract

Objectives To describe preliminary use of a forced‐choice preferential looking task for the clinical assessment of vision in dogs. Materials and Methods The vision of 18 pet dogs was investigated in two separate studies using a forced‐choice preferential looking task: multiple observers watched eye, head and body movements on video recordings to identify cues suggesting when a dog had seen the feature of interest. Human observer reliability was determined using eight dogs and computer‐generated stimuli. Visual acuity was assessed using computer‐generated grating stimuli: in real‐time, an observer watched each dog's eye movement patterns and behaviour to decide whether each grating was seen. Stimuli were presented in a step‐wise manner and were controlled by the observer. Acuity was estimated as the highest spatial frequency the dog was determined to have seen. Results Median estimated visual acuity was better at 1 m compared to that at 3 m. Average test time was longer at a 3‐m distance than at 1 m. Inter‐ and intra‐observer reliability was better from 1 m than from 3 m. Clinical Significance Preliminary use of a forced‐choice preferential looking task for measurement of visual acuity in dogs has potential use as a clinical tool for the assessment of vision in dogs.

Illusory contour perception in domestic dogs

“…Three subjects did not move on to the test experiment as they were not able to successfully complete the discrimination trainings. It is important to note that as a part of a larger on-going project, many of the dogs that participated in this experiment underwent an ophthalmological examination (Byosiere et al, 2018) and a test of visual acuity (Graham et al, 2018). These assessments revealed no abnormalities such as myopia or hypermetropia (i.e., nearsightedness or farsightedness) that may have affected visual acuity.…”

“…We reason that alternative strategies are less likely to underlie the results we obtained, given that these alternative strategies may often require more cognitive analytical reasoning than basing decisions on perceiving illusory contours. The dogs that participated in this experiment had all undergone similar, if not identical, training and testing across a variety of size discrimination, stimulus generalization, and illusion susceptibility tasks (Byosiere et al, 2019;Byosiere, Feng, Rutter, et al, 2017;Byosiere et al, 2016;Byosiere et al, 2018;Graham et al, 2018). Moreover, to control for specific factors, all dogs tested were purebred Lagotto Romagnolo dogs that were genetically related, with similar living conditions.…”

“…As a part of a longer-term investigation evaluating visual perception in dogs (Byosiere, Chouinard, Howell, & Bennett, 2019;Byosiere, Feng, Rutter, et al, 2017;Byosiere et al, 2016;Graham et al, 2018), subjects were first target-trained to nose-touch a single black circle stimulus. The targeting behavior was then transferred to a two-choice discrimination task in which circles of different sizes were presented in pairs.…”

Illusion susceptibility in domestic dogs

“…It is possible that the reversed and null findings are by‐products of limitations in canine visual acuity. While various studies do report that canine visual acuity is worse than humans (Byosiere, Chouinard, et al, 2017; Miller & Murphy, 1995), this explanation may not completely address the variation as recent research in dogs (including subjects whose illusion susceptibility was evaluated) suggests that canine visual acuity is better than what has previously reported (Graham et al, 2018; Lind, Milton, Andersson, Jensen, & Roth, 2017). Additional research should be conducted to confirm these conclusions.…”

Grating Visual Acuity in phakic, aphakic, and pseudophakic Poodles

“…A study which examined four-year-old Lagotto Romagnolo dogs using Teller Acuity Cards, similarly to those used in children, reported a mean VA of 6.5 cpd. 30 Other studies in Beagle and Shiba Inu dogs have given results between 7.0 and 9.5 cpd using pattern-reversal VEP. 2,31 Visual acuities of between 3.75 and 7.5 cpd were found in adult felines.…”