LOW VISION BY PROFESSOR DR WASEEM AHMED KHAN

LOW VISION BY PROFESSOR DR. WASEEM AHMED KHAN

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

CLASSIFICATION OF LOW VISION Category Corrected VA- better eye HHO definition Working 0 6/6 -6/18 Normal 1 <6/18 -6/60 2 <6/60 -3/60 Visual Impairment Severe Visual Impairment Low Vision 3 <3/60 -1/60 Blind 4 <1/60 -PL Blind 5 No PL Blind Low Vision Total Blindness

ETIOLOGY Irreversible damage to ocular media or visual pathway. CHILDREN Albinism Ø ROP Ø Congenital malformation Ø Optic neuropathy Ø

YOUNG ADULT Keratoconus Ø Ocular injuries Ø Aniridia Ø OLD AGE ARMD Cataract Ø Macular degeneration Ø Retinal degeneration Ø

COMMON CONDITIONS ü ü ü ü ARMD DIABETIC RETINOPATHY ALBINISM RETINITIS PIGMENTOSA HISTOPLASMOSIS STARGARDT’S DISEASES ANIRIDIA GLAUCOMA NYSTAGMUS OPTIC ATROPHY COLOBOMA CATARACT RETINAL DETACHMENT KERATOCONUS

CLINICAL ASSESSMENT EVALUATION External observation Ø Detailed history taking Ø Functional vision assessment Ø Defining goals of the patient Ø MANAGEMENT Trial & selection of LVD Ø Low vision device training Ø Counseling Ø

CLINICAL ASSESSMENT EXTERNAL OBSERVATION a. In the waiting area b. On entering the examination room c. Mannerisms of the patient d. Physical appearance e. Communication skill DETAILED HISTORY a. Occupation b. Living situation c. General health d. Other limitations e. Family history f. Previous low vision care

CLINICAL ASSESSMENT DIFFICULTY IN VISUAL TASKS a. b. c. d. e. f. Distance visual tasks Near visual tasks Computer usage Light sensitivity Mobility issues ADL

LOW VISION EVALUATION Following function are evaluated in low vision patient o Visual acuity o Refraction o Contrast sensitivity o Color vision testing o Visual field assessment

MANAGEMENT OF LOW VISION PATIENT LOW VISION DEVICE: It is a device that enables the patient to improve his/her residual visual performance & helps to attain functional vision for the particular task of concern CATEGORIES OF LVD: ü Optical ü Non optical ü Electronic ü Assistive devices

OPTICAL LOW VISION DEVICES BASIC PRINCIPLE : MAGNIFICATION. Enlarges image on retina to stimulate more retinal cells Can be achieved in many ways Relative Distance Relative Size Optical / Angular Electronic. DISTANT OPTICAL AIDS 1. Telescopes 2. Projection Devices 3. Pin- Hole Spectacles 4. See TV NEAR OPTICAL AIDS 1. Spectacle Magnifiers 2. Stand Magnifiers 3. Dome Magnifiers 4. Bar Readers etc. ü ü ü

NON OPTICAL LOW VISION DEVICES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Reading lamp Reading stand Writing guide Reading guide Signature guide Bold line note books and papers Black ink bold tip pens Soft lead pencil – 2 B, 4 B, 6 B Needle threader Notex etc…

ELECTRONIC/ASSITIVE LOW VISION DEVICES FOR NEAR § Closed circuit television CCTV FOR DISTANCE Portable CCTV § Buddy player § Quick look zoom § Classmate reader