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Response variability for multi-dimensional perimetric stimuli in glaucoma [Abstract]

Rountree, Lindsay, Mulholland, P. J., Anderson, Roger S. and Redmond, Tony 2016. Response variability for multi-dimensional perimetric stimuli in glaucoma [Abstract]. Ophthalmic and Physiological Optics 36 (6) , p. 8. 10.1111/opo.12329

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Abstract

Purpose: To compare variability characteristics of four different stimuli for measuring changes in spatial summation clinically in patients with glaucoma. Methods: Psychometric functions were measured using the method of constant stimuli for four stimulus forms in 19 patients with glaucoma (median age, IQR: 69.4, 66.7–72.6 years; median MD, IQR: -5.7, -8.5–-2.8dB), and 10 age-similar healthy controls (median age, IQR: 66.3, 62.3–72.1 years; median MD, IQR: +0.4, -0.4-+1.0dB). Achromatic stimuli were presented at 4 diagonal visual field locations (9.9° eccentricity) on an OLED display (background: 10cd/m2 ). Stimuli were: (i) fixed contrast (0.5, suprathreshold at Ricco’s area) varying in area; (ii) fixed area, within Ricco’s area (0.02deg2 ), varying in contrast; (iii) area and contrast varying simultaneously, and (iv) fixed area, equivalent to Goldmann III (0.15deg2 ), varying in contrast (control). Energy increments and visibility were equated across stimulus forms. Threshold (50% seen) and response variability (slope), were derived from each function. Dependence of response variability on the severity of visual field damage was investigated with linear regression. Results: Response variability increased with severity of damage for all stimulus forms. The smallest increase was found for stimulus (i) (regression line slope: 0.17, p=0.07). The increase in variability was statistically significant for all other stimuli (mean slope 0.2, all p<0.01). Conclusions: Stimuli of fixed contrast (suprathreshold at Ricco’s area) varying in area offers lowest dependence of response variability on disease severity. This may offer advantages for more accurate identification of true changes in visual field damage, particularly in moderate-advanced disease.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Optometry and Vision Sciences
Subjects: R Medicine > RE Ophthalmology
Publisher: Wiley-Blackwell
ISSN: 0275-5408
Last Modified: 05 Sep 2020 01:39
URI: http://orca.cf.ac.uk/id/eprint/99913

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