Low Vision Study Comparing EV Training vs. CCTV for AMD Rehabilitation

Age-related macular degeneration is the single most common cause of visual impairment in Canada, affecting people over the age of 55 years. It causes loss of central, detailed vision, resulting in difficulty with fine vision tasks, such as reading and writing. At present there is no fully effective prevention or treatment for this condition, but people do benefit from visual rehabilitation. Two of the most common rehabilitation techniques are eccentric viewing training and an electronic magnification system called a Closed circuit television (CCTV). In eccentric viewing training the person is taught to use his or her remaining side vision, instead of central vision. The CCTV provides high levels of magnification to compensate for the loss of detail vision. The purpose of this randomized clinical trial is to compare the effectiveness of these two interventions. In the study people will be randomly assigned to either receiving eccentric viewing training or a CCTV. This will happen after they have received basic, optical low vision services and training through the CNIB. We will assess their performance with either the CCTV or EV training with a variety of reading tasks and questionnaires. The results will give evidence for how it is most beneficial to use resources and as such will be very important in future planning of low vision services.

Hypothesis: Eccentric Viewing Training will improve reading speed over CCTV by at least 10 words per minute in patients with advanced AMD.

Inclusion criteria

• First time AMD patient sent to CNIB for visual rehabilitation
• Macular Degeneration reducing visual acuity (VA) to between 20/160 and 20/400 (ETDRS scale)
• Over the age of 50 years
• English as the first language and able to read

Exclusion criteria

• Expected anti-VEGF or Visudyne treatment over the course of the study
• Individuals who do not have reading as a life goal
• Mental cognition that makes learning the specific rehabilitation tasks unlikely (determined by mini-mental state exam)
• Any other ocular pathology that can reduce central vision including cornea decompensation (scar or thickness), cataract (grade III or more for each type of cataract), vitritis (2+ or more) or advanced glaucoma (C/D ratio of >0.7)