Clinical performance of electronic, head-mounted, low-vision devices.
This study compared four electronic head-mounted devices (HMDs) (Jordy, Flipperport, Maxport and NuVision) with conventional optical low-vision aids (LVAs). The aim was to determine any performance differences for laboratory-based clinical measurements and practical visual tasks for patients with macular disease. Possible factors influencing success were explored. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used the four HMDs, habitual spectacles and previously prescribed optical LVAs to complete a range of clinical measurements and everyday visual tasks. The clinical measurements were distance, intermediate and near acuities, and contrast sensitivity. The visual tasks were to read text of three sizes, to write a cheque and to identify grocery items on a shelf. Following the initial evaluation, each subject took home two randomly selected HMD devices for 2 weeks, after which performance measures were repeated. No single HMD stood out as being superior overall. Flipperport and Jordy provided significantly better distance and intermediate acuity than the previously prescribed optical LVAs but near acuity and contrast sensitivity were not consistently better with any of the HMDs. Practice at home provided some improvement in performance with HMDs, nevertheless, optical aids remained the best devices for optimum functioning for the majority of tasks. Younger patients and those with better distance acuity were more likely to benefit from HMDs, particularly when reading small print. In low vision clinics, practitioners should continue to show patients conventional optical aids and demonstrate these electronic HMDs only when appropriate for the individual patient.