Optical aids are means through which the size of the image that occurs in the retina is expanded and can be distinguished better. This expansion can be obtained with different systems such as:
- Magnifying Glasses: are convex lenses (that converge), that increase the object’s size and usually can be used for near vision (i.e. check prices, expiration dates, phone numbers). There are different types of magnifiers: manual, manual with light, with support, fixed focus, focusable, etc.
- Microscopes: are high diopter lenses, similar to magnifiers but mounted on glasses. Thus leaving the hands free they allow reading with more comfort and greater visual field.
You can make them with monocular or binocular prism, with aspheric lenses, bi-aspheric, doublet lenses, with selective filters, etc. and increase graduation for each person according to his needs.
- Telescopes: are optical systems that increase size and zoom in objects that are at far distances. They can be manual for casual use (i.e. to see numbers of bus, reading a sign, looking the name of a street, etc.), or mounted on glasses for prolonged use such as watching television, a play at the theatre, etc. They are placed in different positions (mounted on top, middle or bottom position), depending on the task we want to perform.
- Telemicrosopios: are basically telescopes modified to focus at intermediate distance or near vision, such as seeing the computer screen, reading, sewing, playing cards, etc.
- Selective Filters: are lenses that absorb part of the spectrum of blue light and ultraviolet light, protecting the eye from these harmful radiations.
It has been shown in various scientific studies that the wavelength’s spectre of the blue-ultraviolet light is harmful to the eye, being a factor that accelerates eye diseases such as cataracts, macular degeneration or retinitis pigmentosa.
Using these filters the person has fewer glares without losing visual acuity, improved contrast sensitivity, increased visual comfort, and even increased reading speed and therefore greater reading comprehension.
Among these selective filters there are Corning selective filters, internationally recognized and which provide maximum protection from harmful lights. The person will choose the most appropriate colour, depending on the environmental light where he lives and his degree of photosensitivity.
They can also be mounted on doublet filters with a lighter filter on top of a darker one for very bright places.