Low vision aids opthalmology by mior.pptx

Low visiin aids presentations for patients wuth low vision below 6/18 wuth unkown cause and know cause prepared by a resident in giza ophthalmology research institute for opthalmlogy . There also a clinic in our institute to recieve referal from multiple clinics

1. Dr. Hanan M. Abdelalim MD Ophthalmology consultant MIOR + LVA TEAM LOW VISION AIDS

2. The WHO working definition of low vision A person with low vision is one who has impairment of visual functioning even after treatment and standard refractive correction visual aquity of less than 6/18 to light perception or a visual field of less than 10 degrees from the point of fixation but who uses or potentially able to use vision for planning and execution of task. Definition

3. The most common types of low vision include : Loss of central vision : There is a blind spot in the center of one's vision. Loss of peripheral (side) vision : The inability to see anything to either side, above, or below eye level. Central vision, however, remains intact. Night blindness : The inability to see in poorly lit areas such as theaters, as well as outside at night. Blurred vision : Objects both near and far appear out of focus. Hazy vision : The entire field of vision appears to be covered with a film or glare.

4. Many eye diseases can cause low vision. These can include: Macular degeneration Glaucoma Diabetic retinopathy Retinitis pigmentosa Eye injuries Eye diseases are more common in persons over 50 years of age. Because seeing involves both the eye and the brain, diseases that affect the brain, such as strokes, also can lead to low vision. Low vision in a child can be caused by some of the same conditions as in adults. But there are other possible causes of childhood low vision.

5. Glaucoma

6. Diabetic retinopathy

7. Retinitis pigmentosa Definition: Retinitis pigmentosa is a group of related eye disorders that cause progressive vision loss(Genetic disease) Signs and Symptoms Early signs and symptoms of retinitis pigmentosA Problems with night vision. Problems seeing in dim light. Blind spots in peripheral (side) vision. Later retinitis pigmentosa signs and symptoms may include: Having a sensation of twinkling or flashing light. Having tunnel vision (only central vision). Being sensitive to or uncomfortable in bright light (photophobia). Losing the ability to see color. Having very low vision.

8. Congenital Diseases (Present at Birth) Optic nerve hypoplasia (small  optic nerves ) Cataract Glaucoma Inherited Diseases (Runs in a Family) Retinitis pigmentosa Optic atrophy Acquired Diseases (Develop After Birth) Glaucoma Eye injury Retinopathy of prematurity  (eye disease of premature infants) Cerebral/cortical visual impairment (from brain damage) causes

9. Visual assesment History Ocular history : To know the cause To know progression of the disease Systemic diseases: that may pose difficulty in using certain devices eg.tremors

10. Visual aquity Distance visual aquity : test distance of 2 meters can be used to cover visual aquity up to 20/400 Near visual aquity Contrast sensitivity

11. Glare History Measuring visual aquity both with and without illumination in the chart Colour vision Look for dominant eye by test contrast sensitivity monocularly and binocularly Visual field analysis Peripheral field using Humphery or octopus Central field using amsler grid

12. Types of low vision aids Optical devices Types of optical aids for Distance Intermediate distance Near Non optical devi ces

13. Optical devices Magnifing spectacles Hand magnifiers Stand magnifiers Telescopes Intraocular low vision aids. Other optical devices

14. Magnifing spectacles High plus lens Magnification is ¼ the power of the lens Suited for inear and intermediate distance Monocular or binocular

15. Hand magnifiers Indicated for spot or short time tasks Available from +4.00 D to +40 D Available in three designs: Aspheric Aplantic Bi aspheric

16. Stand magnifier Forms avirtual image ashort distance behind the lens Has fixed focus

17. Control brightness and contrast Magnification varies from 3x to 60 x Closed circuit television

18. Telescopes Magnify distant objects Telescopes wth magnification power from 2x to 10x are prescribed Objective lens is converging

19. Types of Telescopes : Galilean or Keplerian Hand-held, spectacle-mounted, or clip-on Monocular or binocular Fixed focus, focusable telescope, or autofocus

20. Absorptive lenses Tinted ophotochromatic lenses Filters Polarization Visual field enhancement devices Fresnel prism Hemianopic mirrors Other optical devices

21. Non optical devices

22. Partially sighted patient should be encouraged to move as close as possible to the object Approach magnification

23. Illumination Positioning Light source should be at the side ofbetter eye High level of illumination is needed with Lost cone function Glaucoma Diabetic retinopathy Retinitis pigmentosa Reduced illumination Albinism Aniridia

24. Reading stand Writing guide

25. Contrast enhancement Using light color against black and dark color Relative size devices Electronic megnifiers

26. Mobility assisting device

27. Newer technology Intraocular LVA Bionic eye

28. Thank you