Non optical device

1. Non optical devices.
These are aids other than lenses that may
supplement lenses or may be used independently

2. Approach magnification
• Partially sighted patients should be encourage to
move as close as possible to the screen while
watching TV.

3. Lighting Arrangement
• Lighting necessity varies for every individual and
depends on the diagnosis and extend of pathology
• Low vision lighting : disease such as Aniridi,
achromatopsia and albinism required.
• High illumination :Gluocoma, retinitis pigmentosa,
optic atrophy, nuclear cataract required.
• Natural light :adequate lighting for most low vn
children.

4. Contrast Enhancement And Glare
Reduction.
• Reading aid :
• * typoscope as a line guide ..
• *reducing glare from surface ofof white page.
• Light control :
• *important to enhance contrast and reduce the glare.
• * type, position and intensity ot light source monitored.
• Absorptive lenses:*
• * yellow for lowlow light environment.
• * amber for more intense lighting *good prescription
options.

5. Linear Magnification
• Low vision: large print books and periodicals,
• large print playing cards,
• enlarge telephone dials and high-contrast clock
faces
• Enlarging photocopiers may be help for reading
specific documents.

6. Personal Items & Auditory Aids
• Magnifying mirror and needle threader make
visually impaired person easier
• Talking clock's and watches, computers with speech
synthesizer, large print calculators available
• Used by visually handicapped person.

7. Electronic Magnifiers
• Closed- circult television,
• Large print computer,
• Low vision Imaging system
• V-max

8. Closed- circuit Television
• CCTV camera picks up reading material, magnifiers and displays
on the TV screen.
• Provide excellent contract and magnification.
• Advantage: over optical system
• Provides a distortion free, brighter, magnified image with
enhanced contract on a large screen.
• White letters onon block screen help important of image clarity
• Limitations: CCTV is expensive, heavy, difficult to move around.

9. Writing And Communication
Device.
• Handwriting guides
• Signature guides
• Check guides
• Bold line papers
• Tactile or raised line paper
• Felt tip pens or markers ( block)

10. Medical Assistive Device
• Large print or talking mode
• (Ex. Diabetic assistive devices, blood pressure
assistive devices and thermometer.)

11. Orientation And Mobility LVAs
• Primary Aids :
• 1. Canes
• Long cane (severe vn loss)
• Identification cane
• Support cane( extra support and stability walking)
• 2 . Guide dogs: travel around safety and
independent.
• Commonly used Labradors and golden retriever

12. Secondary Aids : Electronic
• Electronic orientation devices.
• Gps devices.

13. Sensory substitute Assistive And
Adaptive Devices
• Auditory substitutions : talking books, reader
service, audio- descriptive devices
• Tactile substitutions : Braille, paperless Braille
output, non - Braille tactile output.

14. Newer Technology Low Vision
Aids
• 1. E- readers (kindle i-pad) : CCTV.
• 2 . Smart phones and tablets.
• Magnify: iread, iLoupe magnify use the device.
• Sight book : Digital communication vn changes to
ophthalmologist (wireless)
• Map Quest: (apple /Android phone) provide voice-
guided directions...tell thethe driver when to turn.
• Voice interface: voice recognition system on i-phone 4s.
Use to check weather, email or calendar.

15. GLARE
• A good lighting system, as well as providing a
suitable level of illumination, must avoid glare.
• Types of glare:
• Disability glare
• Discomfort glare

16. Disability glare
• Usually presences of very bright light
• Impairs the ability to see the detail without
necessarily causing visual discomfort.
• Associate with excessive light received by the eye,
either directly from the light source

17. Discomfort glare
• Visual comfort without necessarily impairing the
ability to see

18. Control of glare
• Shiny or specular surfaces should be avoided.
Possibility of bright images being reflected. Use
matt surface.
• Luminaries should be installed at the correct
mounting heights and spacing, otherwise uneven
lighting will occur.
• Source luminance should be kept at a minimum;
use diffusers or screens
• The glare source should be moved out of the line of
sight.