Development of optokinetic tracking software for objective evaluation of visual function in rodents

Francisco Segura,Ana Sánchez-Cano,Elvira Orduna-Hospital,Isabel Pinilla,Lorena Perdices,Justo Arines,Lorena Fuentes-Broto

doi:10.1038/s41598-018-28394-x

Abstract

The aim of this study was to develop software that performs the optokinetic tracking assessment without the involvement of experimenters to increase the objectivity of the test. To check the effectiveness of the software, several videos were analyzed and the results were compared to those produced by two experimenters. Videos consisted of visual acuity and contrast sensitivity tests on normal animals and pigmented P23H rats (animal model of retinitis pigmentosa). Our software showed a reasonably high success rate: in approximately 78% of the cases, both the software program and the experimenters were in agreement, including the direction of rotation. The software detected 7% false positive cases, 10% false negative cases, and it was wrong in 5% of the cases. Decrease in visual function with age in pigmented P23H rats was observed from the first time interval, although minimum thresholds were found in visual parameters at advanced ages. We developed simple software based on current functions included in the Matlab image processing toolbox that was able to recognize, with a reasonably high percentage of success, the subtle head movements of the rodent produced when visual perception of the optokinetic optotype occurs.

Highlights

Retinal neurodegenerative diseases are one of the leading causes of blindness worldwide
The contrast sensitivity (CS) curve had a typical inverted U-shaped with slightly higher values. Both visual acuity (VA) and CS decreased with age in the group of pigmented P23H rats, consistent with the progressive loss of photoreceptors in this neurodegenerative model
Differences between the pigmented P23H rats and the control rats were noticeable from the first temporal interval at P30, indicating that retinal degeneration appeared at early ages

Summary

Introduction

Retinal neurodegenerative diseases are one of the leading causes of blindness worldwide. It is easy to maintain the rodent model and housing and testing the animals is not expensive In both anatomical and functional testing it is possible to study the features of the disease. Anatomical evaluation in animal models is performed by immunohistochemistry that employs specific antibodies or by different imaging techniques including confocal scanning laser ophthalmoscopy or optical coherence tomography. These procedures can be used to identify different cell types and their synaptic connectivity. The development of other devices to test visual function, such as OptoMotry© (CerebralMechanics, Lethbride, Alberta, Canada)[9,10], a non-invasive method for assessing optokinetic tracking of rodents in vivo, allows for the evaluation of photoreceptor degeneration over time as well as for testing therapeutic interventions without animal euthanasia. The aim of this study was to develop software that performs the optokinetic tracking assessment without the involvement of experimenters to increase the objectivity of the test

Objectives

Methods

Conclusion