Contrasting Blue-on-Yellow with White-on-White Visual Fields: Roles of Visual Adaptation for Healthy Peri- or Postmenopausal Women Younger Than 70 Years of Age

Abstract

To test the hypothesis that differences between short-wavelength automated perimetry (SWAP) and white-on-white visual field sensitivities are related to between-individual variation in the visual adaptation properties of SWS cone pathways. Twenty-six healthy amenorrheic (peri- or postmenopausal) women not using hormonal medication were tested. Subjects ranged in age from 48 to 68 years. They were tested by using foveal increment-threshold techniques and also with two types of 24-2 visual field tests: a full-threshold SWAP blue-on-yellow (B/Y) test and a white-on-white (W/W) test obtained using a Swedish Interactive Threshold Algorithm (SITA Standard). The age-corrected sensitivity differences between the two types of visual fields were compared against foveal measures of visual sensitivity and adaptation, which were obtained psychophysically using dim and bright yellow backgrounds. All measurements for each subject were made at a single testing session. The comparisons were made for the entire visual field and for separate portions of the visual field. The analyses also included pupil size data obtained during visual field testing. The B/Y minus W/W (B/Y - W/W) mean deviation difference was described (R = 0.80) by a multilinear model with three significant factors: (1) an adaptation factor and (2) a baseline sensitivity factor, each derived from the foveal psychophysical data for short-wavelength test stimuli, and (3) a pupil size factor, as recorded for SWAP. The total deviation differences in the periphery of the visual field (approximately 22 degrees from fixation) were described (R = 0.87) by a model with four significant factors, the fourth being an "eccentricity factor" describing the rate of change of the B/Y - W/W total deviation difference measured as a function of increasing retinal eccentricity approximately 9 degrees -17 degrees from fixation. More than 40% of the variance in the B/Y - W/W mean deviation differences was accounted for either directly or indirectly (via effects of pupil size) by variations in adaptation to the yellow background used for SWAP. Much of the extra variability in SWAP sensitivities for a select group of healthy women can be accounted for by differences in the degree of desensitization induced by the yellow background used for SWAP. For clinical practice, pupil status (dilated or undilated) should be altered only with caution from one SWAP testing session to another.