Lighting Needs and Lighting Comfort during Reading with Age-Related Macular Degeneration

This study investigated the effects of changes in luminance on the oral reading speeds of 13 participants with age-related macular degeneration (AMD) and a control group of six age-matched persons with typical vision. For the AMD participants, self-reports of light preferences were also recorded. In the AMD group, reading rates depended on light levels and were considerably lower than those of the control group. Reading speeds differed substantially among the AMD participants and, to obtain a functional range of luminance levels for reading, a combination of objective measurements and self-reports were required.

Changes in Fixation Stability with Time during Binocular and Monocular Viewing in Maculopathy

The purpose of this study was to examine changes in fixation stability over time during binocular and monocular viewing in patients with age-related macular degeneration (AMD). Seventeen patients with AMD and 17 controls were enrolled. Using an EyeLink eyetracker (SR Research Ltd., Mississauga, Ontario, Canada), fixation stability was recorded binocularly and monocularly with each eye for a duration of 15 s while the fellow eye was covered. Fixation stability was analyzed over 3 s intervals for each condition using a 68% bivariate contour ellipse area. Fixation stability did not change with time during binocular viewing for both groups, both monocular conditions for the control group, and monocular viewing with the better eye for the AMD group. However, during monocular viewing with the worse eye, the test of within-subject contrasts showed linear improvement in fixation stability with time (p = 0.016). In conclusion, in patients with AMD, monocular fixational control with the worse eye is poor, but improves with time.

Contrast sensitivity and the effect of 60-hour sleep deprivation

PURPOSE

The study aimed to evaluate the possible influence of prolonged sleep deprivation on achromatic and chromatic (red-green and blue-yellow) contrast sensitivity (CS).

METHODS

During 60-hr sleep deprivation, CS was measured in 11 naval officers every sixth hour using videographic (Vigra-C) sine-wave-generated stimuli.

RESULTS

When comparing the CS measurements obtained in the first and last 24 hr of the study, no statistically significant mean changes of achromatic CS (2.0, 5.9 and 11.8 cpd) or yellow-blue CS (0.6, 2.0 and 4.7 cpd) were found, while a significantly increased mean red-green CS at 2.0 and 4.7 cpd was recorded in the last 24 hr (p = 0.003 in both). The variance of achromatic and chromatic CS measurements in the group did not differ significantly in the first and last 24 hr test periods.

CONCLUSIONS

Prolonged sleep deprivation does apparently not cause clinically or occupationally significant changes of contrast sensitivity in otherwise healthy subjects with normal visual acuity.

Retinal-image quality and contrast-sensitivity function in age-related macular degeneration

PURPOSE

In this article, retinal-image quality and contrast sensitivity were measured in 25 patients with age-related macular degeneration (ARMD) and 15 patients with normal retinal health.

MATERIALS AND METHOD

Retinal-image quality was evaluated with an objective device based on the double-pass technique, and for visual performance we measured the contrast-sensitivity function.

RESULTS

The results from double-pass device revealed the Strehl ratio to be significantly (p < 0.0001) lower for the ARMD group with a 54.3% reduction for 3 mm pupil size and a 46.9% reduction for 4 mm. Contrast-sensitivity function for ARMD subjects was also significantly lower than for the control group (p < 0.05) with a 38.6% reduction.

CONCLUSIONS

Patients affected with ARMD showed poorer retinal-image quality and visual performance than normal subjects. The use of objective devices based on the double-pass technique could be useful for the accurate description of the retinal-image quality of ARMD eyes, in which retinal scattering is significantly increased.