Fixation stability and reading speed in patients with newly developed macular disease.

Abstract

Patients with macular disease and central scotomas must use a peripheral, preferred retinal locus (PRL) in place of their damaged fovea. This paper investigates the development of the PRL, with particular reference to the stability of fixation. Twenty-five patients with age-related and juvenile macular disease were recruited. All patients had developed a scotoma in their better eye within the previous 2 weeks. Patients were assessed using a scanning laser ophthalmoscope and an infra-red gazetracker on four further occasions over the next 12 months. A linear relationship exists between reading speed and fixation stability for patients and control subjects. Fixation stability was not related to scotoma size, visual acuity or contrast sensitivity. Changes in fixation stability account for 54% of the variance in change in reading speed over the course of this study. The deficit in reading speed in patients with macular disease can be partially attributed to impairments in fixation stability.