Dogs as a model of human retinal disease : extensions of the full-field electroretinogram to characterize normal and altered retinal function and applications to translatable gene augmentation therapy

Dogs are an important model of human retinal disease and are frequently used to develop and test translational therapies. Accurate characterization and quantification of the full-field electroretinogram (ERG) is essential in assessing potential treatments, yet many methods used to study the human ERG are rarely used in canine studies. This study aims to assess the utility of several mathematical models of the a- and b-waves and expanded protocols - such as chromatic, increasing background luminance, extended flickers, and long-duration flashes - in characterizing and analyzing the canine ERG. This study establishes baseline parameters for normal canine retinal function and quantifies the altered function in several dog models of human retinal disease. The results of this study demonstrate that mathematical models of the ERG waveforms provide excellent fits in normal dogs, and that expanded protocols better characterize rod and cone contributions to the canine ERG. These methods additionally enable direct comparison of quantified parameters between normal dogs and dog models of human disease as well as longitudinal assessment of disease progression and response to treatment with gene augmentation therapy. The results indicate that incorporating these methods adds valuable information of retinal function. Further research is needed to assess the reliability of these methods across breeds and different recording conditions.