PURPOSE. Low power lasers have been used for purposes ranging from scanning laser ophthalmoscopes to heads-up displays for aircraft pilots. In this study we have begun a formal examination of one possible application as a reading display for low vision patients. The prototype device, called Nomad, is a monocular, head-mounted display that uses a red laser to display text onto the retina. A CCTV camera and XY table provided input. METHOD. Twenty subjects read with the prescribed optical device, CCTV, and Nomad. Data was collected on subject visual acuity, pathology, contrast sensitivity, duration of visual disability, and reading speed and reading duration with each device. In addition subjective impressions of the Nomad were gathered using both forced choice and open-ended questions.
RESULTS. Subject reading speeds with the Nomad were faster than optical devices, but slower than CCTV. Reading durations with the Nomad were similar to that with CCTV; both of which were about 3X longer than optical devices. Subjective data indicated that subjects would prefer another color, or full-color laser for the Nomad and would like a more comfortable head-mount. Most subjects preferred the brightness and sharpness of the Nomad display to the displays of the optical devices and CCTVs. The brightness and high contrast may allow patients with extremely low vision to maintain the ability to read visually even when conventional devices are no longer effective.
CONCLUSIONS. The Nomad is a prototype display with potential as both a distance and near vision aid. At present it is a useful research tool to begin examining the potential benefits of new visual display technology. We will discuss our findings in relation to this potential.