The Peli Lens is a
mobility aid
A mobility aid is a device designed to assist individuals with impaired movement. These devices help people walk, maintain balance, or get around more easily.
Mobility aids include walking supports like canes, crutches, and walkers for those w ...
for people with
homonymous hemianopia
In linguistics, homonyms are words which are either; '' homographs''—words that mean different things, but have the same spelling (regardless of pronunciation), or '' homophones''—words that mean different things, but have the same pronunciat ...
. It is also known as “EP” or Expansion Prism concept and was developed by Dr.
Eli Peli o
Schepens Eye Research Institutein 1999. It expands the
visual field
The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it i ...
by 20 degrees. He tested this concept on several patients in his private practice with great success using 40Δ Fresnel press-on prisms (Peli 2000). Development of the lens and clinical trials were funded by NEI-NIH Grant EY014723 awarded to Chadwick Optical. The results of the multi-center clinical trials were published in 2008 reporting a 74% patient acceptance rate.
[Bowers A, Keeney K, Peli E. (2008) Community-Based Trial of Peripheral Prism Visual Field Expansion Device for Hemianopia. Archives of Ophthalmology 126(5):657-664] Under this grant Chadwick Optical also designed and produced a cosmetically acceptable permanent version of this concept in a prescription lens.
An improved version of the Peli Lens expanding the visual field by 30 degrees is available. Clinical trial results are pending.
References
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Mobility devices