Abstract
Purpose:
To directly compare various manual prehension movements in participants with central visual field loss (CFL), peripheral visual field loss (PFL) and normal vision controls.
Methods:
Three-dimensional motion data were collected from 17 AMD participants with CFL (age: 82±10 years), 17 glaucoma participants with PFL (age: 74±8 years), and 10 age-matched controls (age: 76±6 years). Participants reached towards and grasped a cylindrical object, and then also transported and placed it at a different peripheral location. Reaction time, overall movement time, grip aperture, movement trajectory and object placement error were measured using a VICON system. Visual function was measured using LogMAR visual acuity (VA), contrast sensitivity (CS) and visual fields (VF) assessments.
Results:
Reach-to-grasp phase: CFL participants exhibited longer reaction times (PFL p=0.02; control p=0.03), overall movement time (PFL p=0.02; control p=0.05) and deceleration time (PFL p<0.01; control p=0.01) when compared to PFL and control participants.<br /> Transport phase: CFL participants exhibited longer movement time (PFL p<0.01; control p=0.01) and lifted the object significantly higher (PFL p<0.01; control p<0.01) than both control and PFL participants. Compared to control participants, CFL participants exhibited significantly increased errors when placing the object in the peripheral location (p<0.01).<br /> In PFL participants VA, CS and central VF (averaged across 5˚, 10˚ and 20˚) were significantly correlated with reach-to-grasp movement time, reach-to-grasp deceleration time and peak transport velocity (p<0.05).
Conclusions:
Participants with central field loss show worse performance when compared to those with peripheral field loss, for both reach-to-grasp and grasp-to-transport tasks. Significant correlations between movement indices and visual function (VA, CS and central VF) in PFL participants indicate that prehension performance is affected when glaucomatous visual field impairments are significant, and encroach on the central visual field.