Functional deficits in early stage age‐related maculopathy

Abstract

Background: It is of interest to examine paracentral functional deficits in early agerelated maculopathy (ARM), as histopathological studies indicate that this is where the earliest changes occur. The purpose of this study is to detect the sensory functional deficits at chosen retinal areas around the fovea and at the fovea itself in patients with early age-related maculopathy and to determine the type of functional losses that are more pronounced in early ARM. Methods: Ten participants with early ARM and 10 age-matched controls took part. Crowded and uncrowded visual acuity and static and transient contrast sensitivity were measured in the same selected eye of each participant at eight predetermined retinal locations plus the fovea in patients with early ARM and controls. All measurements were made using computer-generated targets. Results: A significant difference between the controls and subjects with ARM was found in low spatial frequency static contrast sensitivity (p = 0.05) but not for transient contrast sensitivity (p = 0.586). Visual acuity (uncrowded VA and crowded VA) showed a borderline difference (p = 0.072 and p = 0.084, respectively). Compared to controls, there was no evidence of increased contour interaction effects in early ARM (p = 0.595). Conclusion:The subjects with very early ARM showed significant loss of low spatial frequency static contrast sensitivity before the loss of high contrast VA, indicating that static contrast sensitivity may be one of the earliest functional losses in early ARM and this loss was found to extend across the central 10 degrees of the retina.

Visual acuity loss in patients with age-related macular degeneration measured using a novel high-pass letter chart

“…For the purposes of detecting refractive error, they have been shown to be sensitive to optical defocus as a result of spatial frequency phase reversals 14. However, these conventional letters appear to be relatively poor indicators of visual loss in early and intermediate age-related macular disease 4 15. Klein et al 16 reported a decrease in VA of only two or fewer letters for patients displaying early age-related maculopathy lesions compared with eyes without such early lesions.…”

Simulated loss of foveal vision eliminates visual search advantage in repeated displays

“…This extrafoveal vision has lower spatial resolution compared to foveal vision. Many studies on low-level visual processing have illustrated the immediate consequences of the loss of foveal vision, e.g., reduced visual acuity and contrast sensitivity (Qiu and Leat, 2009) and deficits in orientation discrimination (Bedell et al, 2009) and shape discrimination (Wang et al, 2002). For a review on psychophysical function in AMD, see Neelam et al (2009).…”

Effectiveness of eccentric viewing training for daily visual activities for individuals with age-related macular degeneration: A systematic review and meta-analysis

“…Computerized program can be useful to consistently provide visual stimuli, so be used in exercises of eccentric fixation to reinforce the PRL or TRL (Frennesson, Jakobsson, & Nilsson, 1995;Nilsson, Frennesson, & Nilsson, 2003;Vukicevic & Fitzmaurice, 2009). Palma et al (Palmer, Logan, Nabili, & Dutton, 2010) carried out the training program by specialist as follows: Identification of the preferred eye; Determination of the PRL using Amsler chart (Qiu & Leat, 2009); Optimal magnification and refractive correction; Lighting; Training to identify a suitable PRL by the steady eye strategy; Individualized homework to practice. This review suggested that it was necessary to apply eccentric viewing training program include two steps of determining the PRL and learn through practice for AMD.…”