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Marianna Bacellar-Galdino, Jeffrey Adam Jamison; New device to measure behavioral vision in rodents. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5525.
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© ARVO (1962-2015); The Authors (2016-present)
Visual Acuity is the standard of care for evaluating vision in patients however it is difficult to measure directly in animals. AcuiSee-R is a stand-alone, easy-to-use device, based upon operant-conditioning which provides high-throughput, automated training and standardized testing of visual acuity (spatial density threshold) and contrast sensitivity in laboratory rodents. This work demonstrates that spatial density threshold is dependent on the contrast of the target image and that contrast sensitivity is dependent on the spatial density of the target image.
Using the AcuiSee-R device, eight male Long Evans rats were trained to discriminate between a static image of random noise and one with sinusoidal alternating black and white bars. The image spatial density is reported as the number of sinusoidal cycles per 1 degree of visual angle (c/d) and % contrast is measured using the Michelson method. The spatial density threshold with fixed contrast and contrast sensitivity with fixed spatial density was measured using the method of limits with 5 reversals per exam. The threshold spatial density was measured at 4 fixed contrasts and % contrast sensitivity was measured at 4 fixed spatial density’s. Each animal was tested 4 times at each configuration.
The threshold spatial density for LE rats at high contrast (91.6%) is 0.6 cycles per visual angle (c/d) and as the image contrast is reduced the threshold of detection also decreases (0.5 c/d at 49.12%; 0.45 c/d at 20.54%; and 0.4 c/d at 14.85% contrast). Similarly, the contrast sensitivity at high spatial density (0.1 c/d) is 17%, and as the spatial density of the target is increased the contrast required to detect the target is increased (19% at 0.29 c/d; 32% at 0.45 c/d and 70% at 0.55 c/d spatial density).
AcuiSee-R is a valuable tool to measure behavioral vision in rodents which is more similar to the patient experience of visual acuity and contrast sensitivity in clinic. Demonstrating that spatial density threshold and contrast sensitivity are dependent on the target contrast and spatial density suggests that deficits in vision due to disease will result in similar threshold changes. Future work from this lab will include application of this device in models of glaucoma, diabetes, and dry eye.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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