The purpose of this study is to measure the effectiveness of a newly-designed oculomotor
training program for patients with age-related macular degeneration.
Age-related macular degeneration (AMD) is currently among the top three leading causes of
central vision loss in veterans (Chomsky et al., 1995) and is the most prevalent cause of
blindness among veterans (37.2%, Quillen & Henry, 2000). The loss of central vision
associated with these diseases has a profound impact on the quality of life of those
affected, with many suffering depression. It is devastating to no longer be able to read a
newspaper or recognize facial expressions. The use of preferred retinal locations (PRLs) to
compensate for diseased foveae has offered hope to these patients in regaining some
function. The investigators have developed a protocol that includes training in three major
visual skills areas:
- visual awareness and eccentric viewing;
- reading eye movements; and
- processing of sequentially presented lexical information.
Module 1 focuses on making the patient aware of better vision at an eccentric location
relative to degraded vision at the diseased fovea. Module 2 is focused on the improvement of
the control of eye movements with the PRL. Module 3 is focused on reading practice without
eye movements. These program curriculums and preliminary results are provided in the present
proposal. The primary aim of this proposal is to quantitatively assess the relative
effectiveness for improving reading and to establish the minimum training time need for
skill improvement. Sixty patients with AMD who are already using a PRL will be selected to
be similar in visual characteristics (e.g., visual acuity, contrast sensitivity, size of
scotoma, duration of disease) and included in an experimental group. All patients in the
experimental group will be trained with all three modules using a repeated measures -
completely counterbalanced - design to control for training order effects. An additional 24
AMD patients will be recruited for a control group to be tested at the same time intervals
as the experimental patients, but do not receive training between these assessment period
intervals. The control group patients will be given the option to receive training following
the assessment period. Both the experimental and the control patients will be assessed using
the same outcome measures of reading (using MNRead Acuity Charts, the Pepper Visual Skills
for Reading (VSR) Test, and the View Sentences Test). The performance of the experimental
patients on the outcomes battery post-training will be compared to their pre-training
performance on the same battery. Any change in performance of the experimental patients will
be compared to the test-retest performance of the control patients. A questionnaire (the
Veterans Administration Low Vision Visual Functioning Questionnaire) will also be
administered to assess perceived abilities to perform everyday tasks before and following
training. The control patients will also receive the questionnaire before and after their
assessment period. In addition, the experimental patients will also be assessed on the
exercises practiced during the module at the end of each daily training session to determine
exactly when in the training protocol an improvement in performance on the exercises being
trained has occurred. These daily performance measures provide for a finer scale for
detecting performance changes. Statistical analyses will be conducted to answer the
following key questions:
- What visual skills related to reading are trainable?
- Which methods are best for training these skills?
- What is the time course of visual skill improvement?
- Do the answers to these questions depend upon individual patient characteristics (e.g.,
age, disease severity, PRL location, cognitive factors)?
- Do patients who do not undergo training, but have repeated reading performance
assessments, show improvements in reading skills?
Advances are being made in the area of retinal cell transplantation, gene therapy, and
retinal prosthetics. When these techniques become part of standard clinical care, it is
likely that the patients will require vision rehabilitation techniques to help them make
sense of their potentially fragmented percepts. This research offers an evaluation of
relative successes of the components of reading rehabilitation and will lead to the design
of an efficient and effective composite training strategy.
- Patients with a diagnosis of AMD
- An established preferred retinal locus
- Visual acuity of less than or equal to 20/70 and greater than or equal to 20/400 (in
the better eye)
- Those with other major ophthalmologic and neurologic disease; choroidal
neovascularization ("wet" AMD); moderate to severe media opacities; and cognitive