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A Azuara-Blanco, A Sahraie, P Kinnear, K Taherian; Detection of Acceleration Rather Than Direction of Motion is More Sensitive to Glaucomatous Nerve Damage . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2173.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Changes in motion sensitivity have been reported in many optic neuropathies. In particular, motion perception has been extensively studied in primary open angle glaucoma (POAG) patients. We have previously reported a simple motion model to explain the findings in clinical conditions such as POAG and Optic Neuritis (Sahraie et al., ARVO 2000). One of the model’s predictions was the elevated thresholds for detection of a change in velocity (i.e. acceleration) even in the absence of an increase in motion direction discrimination thresholds. We aimed to investigate this prediction in a group POAG patients and age-matched controls. Methods:An optical projection system was used to generate a continuous, single-dot target. Its velocity and direction of motion were controlled using a fast response servo-controlled mirror scanner. Motion direction and acceleration thresholds were measured for the speed range 1 to 20 °/s at 1° and 10° eccentricities using staircase procedures in a group of nine patients with early or moderate POAG and ten aged-matched controls. The target (subtending 15 arc min) and background luminances were 137 cd/m2 and 585 cd/m2 respectively. Results:No significant increase was observed at 1 eccentricity in motion direction discrimination thresholds, but thresholds for detecting acceleration were significantly elevated in POAG patients. At 10 eccentricity, thresholds for both parameters were significantly elevated as have been reported previously. Conclusion:We have demonstrated that foveal detection of acceleration could be significantly affected even in the absence of a significant increase in motion direction discrimination thresholds. Acceleration thresholds therefore may be a more sensitive indicator of glaucomatous nerve damage.
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