Electronic Devices for Low Vision Patients

Electronic Devices for Low Vision Patients

1. Electronic Devices for Low Vision Patients Nilufa Akter Optometrist ( B.Optom , ICO, CMU) Ispahani Islamia Eye Institute and Hospital

2. Electronic Device/Magnification system Electronic Devices/magnifying systems come in many different varieties and sizes, depending upon the task or activity you want to perform. Includes: a Camera system (for capturing images) and a Monitor (to display the captured images),. Ex. CCTV/Desktop Video magnifier Portable versions(PVM) : which you can take along wherever you go. Ex. Pebble HD, E- Bot 3. Mouse’-style devices 4. Head Mounted ex.( Vmax )

3. Electronic Devices that works on the principle of electronic magnification (projection magnification). Magnification is achieved by projecting or electronically changing an image so that the new image has an increased angular subtend at the eye. • Enlargement of the image is measured directly by dividing the image height measured from the screen by the original object height • Eg : If the image of a 1 cm object produced on the screen measures 9 cm, the enlargement is 9×. • This form of enlargement usually allows longer working distances to be utilized

4. 1.Close Circuit Television/Electronic desktop magnifier Is direct cable link between the camera imaging system and the monitor viewing system (in contrast to broadcast television), but this description generally refers to surveillance devices and does not indicate the provision of features, such as enlargement and contrast enhancement, found in devices for the visually impaired. Consists of 3 major components: 1.camera 2.monitor 3. movable reading platform Best for pt. Having constricted VF, decreased VA, decreased contrast sensitivity secondary to glaucoma, RP, ION.

5. - Video camera is directed at an object and image is projected on TV monitor screen . - Movable platform sits on a flat table/desk - Magnification range: (3x to 100x) and - Viewing modes with lighting, color, and contrast modes for optimal visual assistance.

6. The information is simply gathered in video real time, and displayed in the monitor. The real time video magnification make the CCTV magnifiers a great solution for - writing and performing hands-on activities, - - writing checks - and intricate detail hobbies like needlepoint and model building/painting.

7. Applied uses of CCTV: 1. Educational 2. Vocational 3.Recreational 4.Personal 5.Best for patient Having constricted VF, decreased VA decreased contrast sensitivity secondary to glaucoma, RP, ION.

8. Advantages of CCTV: 1.Adjustable magnification 2.Wide range of magnification (4x to 100x) 3.Reverse Polarity available 4.Flexible working distance 5.Adjustable color and contrast 6.Binocularity possible 7.Adjustable field of view

9. Disadvantages of CCTV: 1.Bulky, not portable 2.Requires more training and practice 3.Difficulty of maintenance 4.More expensive

10. 2. Portable Video Magnifier(PVM) A portable digital magnifier is a device with a camera on the underside that captures the image of text, pictures, or other items, and a monitor on the top side that displays the image.

11. Important Features of Portable Digital Magnifiers: Monitor sizes: - range from 3.5 inches to 13 inches. Other available monitor sizes are 4.3 inches, 5 inches, and 7 inches. Many models: with a high-definition (HD) camera and monitor, while others still come with standard resolution. Most models come with a protective carrying case. They are rechargeable , with an average battery life of about three hours before needing to be recharged. Recharging usually takes about three hours.

12. Advantages of PVM 1. Used or taken anywhere 2. Provide helpful magnification , enhanced contrast, and improved brightness, which is important for many persons with low vision. 3. Less expensive than a CCTV. 4. Provide a fairly wide FOV , as compared with many strong magnifiers.

13. Disadvantages of PVM 1. More expensive than most optical devices 2. Smaller field of view than a CCTV 3. It can be tiring to hold. 4. Some brands may show some distortion on the edges, or the image may fade out in the “false color” mode.

14. 3. Mouse’-style devices • Consist of a camera usually mounted on rollers in a small hand-held case that can be moved over the object of interest •Mouse-style devices are more portable than conventional stand-based EVES

15. 4. Head Mounted- VMax • The V max is the next generation of a head mounted assistance device that address distance , intermediate and near vision . • It is an automatic focus system with the range of magnification 0.8 to 20 times. • One high resolution center colour camera healed on head mounted unit. • FOV of the camera is 47 degrees in horizontal and 36 degree in vertical. • Vmax requires no special fitting procedure -It can fitted over patient prescription spectacles

16. Head Mounted Electronic device MaxPort Magnifier with eyeglasses as display unit FlipperPort Magnifier for distant viewing

17. ADVANTAGES of Head Mounted 1. System can use for variable distance 2. Wide range of magnification 3. Camera has color capability 4. Automatic focus capability 5.System is completely Portable 6. Easy to fit and operate

18. DISADVANTAGE OF VMAX 1. Control box and battery pack are heavy 2. System is expansive 3. System not wildly available

19. Others Electronic magnification system Large Print Computers • Can provide Enlarged print on the screen through either standardized and dedicated software • Software is also available to provide speech for the computer.

20. Thank you