Handwriting with a preferred retinal locus for AMD with scotomas.

Purpose: Individuals with macular scotomas from age-related macular degeneration frequently have difficulty writing legibly. The purpose of this study was to investigate the causes of this difficulty by documenting the location of the retinal image of the pen used for writing in relation to the scotoma and fixational preferred retinal locus (fPRL).

Methods: Subjects with macular scotomas from age-related macular degeneration and visually normal age-matched controls wrote words while observing their hand, pen, and text in a scanning laser ophthalmoscope.

Preferred retinal locus--hand coordination in a maze-tracing task.

Purpose: Fine manual tasks require coordination of vision, eye movements, and motor control. Macular scotomas from age-related macular degeneration (AMD) may adversely affect this coordination. The purpose of this research was to find whether the preferred retina locus for fixation (fPRL) also guided the hand in performing fine manual tasks and how the fingers, fPRL, and scotomas interacted in task performance.

Effect of bilateral macular scotomas from age-related macular degeneration on reach-to-grasp hand movement.

Purpose: Vision plays a critical role in reaching and grasping objects. Consequently, bilateral macular scotomas from age-related macular degeneration (AMD) may affect reach-to-grasp movements. The purpose of this work was to investigate changes in reach-to-grasp movement dynamics and to relate those changes to the characteristics of subjects' preferred retinal loci (PRL), scotomas, and visual acuities.

Visuomotor training improves stroke-related ipsilesional upper extremity impairments.

Background: Unilateral middle cerebral artery infarction has been reported to impair bilateral hand grasp.

Methods: Individuals (5 males and 5 females; age 33-86 years) with chronic unilateral middle cerebral artery stroke (4 right lesions and 6 left lesions) repeatedly lifted a 260-g object. Participants were then trained to lift the object using visuomotor feedback via an oscilloscope that displayed their actual grip force (GF) and a target GF, which roughly matched the physical properties of the object.

Retinal image location of hand, fingers, and objects during manual tasks.

Purpose: A new method was developed using the scanning laser ophthalmoscope (SLO) to investigate the effects of central visual loss on eye-hand coordination in manual tasks. Using the SLO, the retinal positions of the hand, fingers, and objects are imaged and recorded while a subject performs a manual task.

Method: A video camera images the subject's hand and objects to be manipulated in the SLO laser-beam raster, producing a video image of a subject's hand, fingers, and objects on the subject's retina while the objects are manipulated.