Abstract
Abstract: :
Purpose: Patients with Age Related Macular Degeneration (AMD) have unstable fixation, as they spontaneously use several Preferred Retinal Loci (PRL), resulting in poor visual efficiency. We applied new procedures 1) to determine the most efficient retinal locus for trainig (TRL) to optimize rehabilitation of reading, and 2) improve the training of the TRL. We investigated 1) the correlation between the determination of the localisation of a particular retinal zone and reading efficiency, and 2) the contribution of eye-hand coordination training to stabilisation of the TRL, and 3) wether this procedure shortens the number of rehabilitation sessions needed to reach a preset criterion. Methods: 44 patients with bilateral AMD ( Visual acuity ≤.5logMar) were thouroughly assessed with a clinical and functional assessment including: patients’goals, distance and near visual acuities, contrast sensitivity, Goldmann kinetic perimetry, goal-directed hand movement, multisensory, psychological and cognitive status, reading velocity and resistance. They were trained to use a chosen eccentric gaze direction to fixate and stabilise fixation, including during pursuit, saccades and pointing exercises. During this phase the direction of gaze was controlled by the corneal reflex method. In addition, they practiced eye-hand coordination exercises such as crossing, tracing and circling at home. Only after retraining of these spatial modalities were proper letters, words and texts shown to them. Results: 58% of the patients presented with absolute scotomas and 42% relative scotoma. Analysis of the results of kinetic permetry allows the choice of a functional retinal zone which could fit the requirements of fluent reading. The patients develop an appropriate visual strategy of stable and unconscious eccentric fixation within a few rehabilitation sessions (6 to 11). Reading speed rose as high as 100 words per minute. Conclusions: Involvment of visually guided hand movement helps with the stabilization of a TRL for reading. We observed a strong correlation between acquisition of a stable TRL and hand pointing accuracy. Training is faster when the retinal location of the TRL is at a distance from the PRL(s). Simultaneous use of sensory and motor modalities related to spatial tasks is helpful in fostering the strategies involved in reading and daily activities and, more generally, contribute to maintain quality of life.
Keywords: age-related macular degeneration • low vision • clinical laboratory testing