Functional deficits in early stage age‐related maculopathy

Abstract

Background:  It is of interest to examine paracentral functional deficits in early age‐related 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.

Key words:

• age‐related maculopathy
• ARM
• contour interaction
• contrast sensitivity
• crowding

ACKNOWLEDGEMENT

Thanks to Melanie Campbell for encouragement and Trefford Simpson for help with statistical analysis.