Low Vision Aids

by Heather Mason

Low vision devices for near and intermediate tasks

Type	Indications	Features	Limitations
Short working distances	Useful for prolonged reading provided there is adequate magnification for the task.	Inexpensive, cosmetically acceptable. Provides from 1.5x to 8x magnification.	Short, sometimes very short working distances.
Hand magnifiers	For short inspections such as looking at a price tag or an index. As a supplement when necessary for reading smaller print than can be seen with devices used for general reading.	Available in magnifications from 1.5x to lOx. Portable, relatively inexpensive.	Require the use of one hand and no significant hand tremor.
Stand magnifiers	Useful for general reading and in the classroom.	Available in magnifications from 1.5x to 15x. Some models may be mounted in spectacle frames.	Best performance only with short working distance, as little as a few centimetres in higher powers. Higher magnifications usually require use of the short working distance.
Illuminated hand and stand magnifiers	Useful where performance at near improves with increased illumination. Highest powered optical magnifiers, up to 15x. Useful when away from usual light sources.	Features will be the same as the equivalent hand or stand magnifier. Illumination provided by disposable or rechargable batteries, or by mains operated handles in some models.	Limitations will be the same as the equivalent hand or stand magnifier. Will require a replacement of disposable batteries, changing and recharging of rechargable batteries or mains power.
Head-borne magnifiers	For tasks which require use of both hands and where working distance is not critical.	Leave both hands free. Usually mounted on a head band or spectacle frame.	Limited range of magnification. Often cosmetically poor
Near point telescopes	For tasks which require the use of both hands and which cannot be done at very short working distances.	Consist of either a distance telescope with a near attatchment or a telescope designed to be used for near tasks only. Mounted in spectacle frame. Longer working distance than other forms or near low vision aids giving the same magnification.	Cosmetically poor. Limited field of view, as magnification and working distance are achieved at expense of field of view.
Electronic magnifiers	Where performance with optical magnifiers is not sufficient for needs, because of magnification required or the volume of near work required.	Available in higher powers up to 50x magnification and with better field of view than optical magnifiers.	Expensive. Most models are not portable.

Low vision aids