Abstract
Purpose :
Patients with a macula scar can develop a central scotoma which results in central vision loss and difficulties with reading. This may be overcome through an adaptive behavior called eccentric fixation, which involves the projection of images on to an adjacent area of healthy retina instead. We performed a pilot study investigating the usability and acceptance of a newly developed Head Mounted Device application to train eccentric fixation and improve the reading ability of patients with central scotomas.
Methods :
Google Glass is a type of Head Mounted Device which projects virtual images upon a selected area of the retina. Three patients with macular scars and central scotomas were shown numbers of similar font, size and contrast on a standardized computer screen and Google Glass. We showed a series of numerals of decreasing size on each medium and recorded the maximum number of numerals that could be read accurately. An application prototype using rapid serial visual presentation was then created and we obtained feedback from 15 additional patients to optimize the usability of the application.
Results :
Two patients with CS were able to read 11 of 14 numerals accurately using the Head Mounted Device, with less head movements compared with using the computer screen. The other patient was unable to read using the Head Mounted Device due to a large macular scar. Patient feedback on the application prototype resulted in the inclusion of modifiable font properties, text and background colour variations and different types of fixation targets.
Conclusions :
A Head Mounted Device application using rapid serial visual presentation is a promising method of enabling patients with CS to read despite a few limitations in the patient population it may be used in. Rapid serial visual presentation, with the addition of various types of fixation targets, may help overcome Troxler fading and improve reading ability. Intensive training over several sessions with adjustments of the settings for each individual patient may be required for optimal results.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.