Quantitative Assessment of the Canine Pupillary Light Reflex

Whiting, Rebecca E.H.; Yao, Gang; Narfström, Kristina; Pearce, Jacqueline W.; Coates, Joan R.; Dodam, John R.; Castaner, Leilani J.; Katz, Martin L.

doi:10.1167/iovs.13-12012

Cited by 25 publications

(36 citation statements)

References 40 publications

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“…Both TPP1+/+ and TPP1+/− dogs had normal ophthalmic examination findings throughout the study period. The TPP1 −/− dogs in this study showed ophthalmic visual behavior and retinal changes consistent with previous reports (Katz et al, 2008; Katz et al, 2005b; Whiting et al, 2013a). In addition, the majority of TPP1 −/− dogs developed a retinopathy consisting of progressive multifocal retinal detachment lesions.…”

Section: Resultssupporting

confidence: 92%

“…All recordings were done during the light period of the daily 12:12 light-dark cycle. The detailed methods for obtaining the PLRs have been described previously (Whiting et al, 2013b). Dogs were kept in dim light (0.9 lux) for at least 1 hour, including preparation time, and in complete darkness for 10 minutes prior to recording.…”

Section: Methodsmentioning

confidence: 99%

“…Recordings were performed with a custom apparatus (Whiting et al, 2013b) which provided timed delivery of a visible light stimulus from a mounted high-power broad spectrum LED ( MCWHL2 ; Thorlabs Inc., Newton, NJ) and concurrently recorded pupil images at 30 frames per second using an infrared-sensitive camera (PC164CEX-2; Supercircuits Inc., Austin, TX) under continuous infrared illumination (880 nm LED) for visualization of the eye. The direct PLR of the right eye was evaluated using a standardized protocol of 100 millisecond flashes of broad spectrum white light at each of 10 intensities between 8 and 15 log photons/cm 2 /s (0.1 to 1400 lux).…”

Section: Methodsmentioning

confidence: 99%

“…A list of image frame number and corresponding pupil area was exported to a spreadsheet and used to calculate desired parameters. Area measurements were converted from pixels to mm 2 based on the known size of the lid speculum present in each pupil image (Whiting et al, 2013b). …”

Section: Methodsmentioning

confidence: 99%

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Multifocal retinopathy in Dachshunds with CLN2 neuronal ceroid lipofuscinosis

Whiting

Pearce

Castaner

et al. 2015

Experimental Eye Research

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The CLN2 form of neuronal ceroid lipofuscinosis is an autosomal recessively inherited lysosomal storage disease that is characterized by progressive vision loss culminating in blindness, cognitive and motor decline, neurodegeneration, and premature death. CLN2 disease results from mutations in the gene that encodes the soluble lysosomal enzyme tripeptidyl peptidase-1. A null mutation in the TPP1 gene encoding this enzyme causes a CLN2-like disease in Dachshunds. Dachshunds that are homozygous for this mutation serve as a model for human CLN2 disease, exhibiting clinical signs and neuropathology similar to those of children with this disorder. Affected dogs reach end-stage terminal disease status at 10–11 months of age. In addition to retinal changes typical of CLN2 disease, a retinopathy consisting of multifocal, bullous retinal detachment lesions was identified in 65% of (TPP1−/−) dogs in an established research colony. These lesions did not occur in littermates that were heterozygous or homozygous for the normal TPP1 allele. Retinal changes and the functional effects of this multifocal retinopathy were examined objectively over time using ophthalmic examinations, fundus photography, electroretinography (ERG), quantitative pupillary light response (PLR) recording, fluorescein angiography, optical coherence tomography (OCT) and histopathology. The retinopathy consisted of progressive multifocal serous retinal detachments. The severity of the disease-related retinal thinning was no more serious in most detached areas than in adjacent areas of the retina that remained in close apposition to the retinal pigment epithelium. The retinopathy observed in these dogs was somewhat similar to canine multifocal retinopathy (CMR), a disease caused by a mutation of the bestrophin gene BEST1. ERG a-wave amplitudes were relatively preserved in the Dachshunds with CLN2 disease, whether or not they developed the multifocal retinopathy. The retinopathy also had minimal effects on the PLR. Histological evaluation indicated that the CLN2 disease-related retinal degeneration was not exacerbated in areas where the retina was detached except where the detached areas were very large. DNA sequence analysis ruled out a mutation in the BEST1 exons or splice junctions as a cause for the retinopathy. Perfect concordance between the TPP1 mutation and the retinopathy in the large number of dogs examined indicates that the retinopathy most likely occurs as a direct result of the TPP1 mutation. Therefore, inhibition of the development and progression of these lesions can be used as an indicator of the efficacy of therapeutic interventions currently under investigation for the treatment of CLN2 disease in the Dachshund model. In addition, these findings suggest that TPP1 mutations may underlie multifocal retinopathies of unknown cause in animals and humans.

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Section: Resultssupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Multifocal retinopathy in Dachshunds with CLN2 neuronal ceroid lipofuscinosis

Whiting

Pearce

Castaner

et al. 2015

Experimental Eye Research

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“…To draw more definite conclusions regarding retinal function from PLR changes, further studies using research standard pupillography under controlled conditions would be required. 28 The progression of the retinal changes in the dogs monitored appeared to be markedly slow. Repeated ERGs in two affected dogs showed no detectable differences after 6 months in dog #2 and a slight reduction in the remaining cone function in dog #1 after 2 years.…”

Section: Discussionmentioning

confidence: 97%