Design and Clinical Evaluation of a Smartphone-based Low Vision Enhancement System
Condition: Low Vision
MeSH terms: Vision, Low
Study type: Interventional

Summary: 
      The primary objective is to compare the effectiveness and adverse side-effects of the virtual
      bioptic telescope and virtual projection screen in a new head-mounted video-based low vision
      enhancement system (LVES) with a wide field of view to currently employed specifications for
      head-mounted video display low vision enhancement technology. Secondary objectives are to
      acquire qualitative information from patients to evaluate the functioning of the system, to
      optimize system features and operations, and to assess the value patients place on system
      features, functions, and operating parameters relative to those of current technology.
      Investigators will conduct a comparative effectiveness study to determine if the novel vision
      enhancing features of LVES 2 provide low vision patients with benefits superior to those
      provided by existing technology.
    

Detailed description: 
      The study will employ a single center, randomized crossover design with a 2-week trial period
      before the crossover, a 22-week washout period, and a 2-week trial period after the cross
      over. Once recruited patients have consented to participate in eligibility screening for the
      study, participants will be administered the Activity Inventory (AI), a rating scale
      questionnaire about the difficulty of performing a wide range of daily activities and the
      Telephone Interview for Cognitive Status (TICS) Eligible patients who consent to participate
      will be randomized to Group A or Group B. Group A will be trained to use and will employ at
      home for the first 2-week trial period, the headset with the new LVES 2 features and
      specifications and then, after the 22-week washout period, will be trained to use and employ
      at home for the second 2-week trial period the headset with currently available features and
      specifications ("legacy system"). The order will be reversed for Group B who will start with
      the legacy system for trial period 1 and then switch to the new LVES 2 system for trial
      period 2 after the 22-week washout.

      Prior to each 2-week trial period, participants will visit the laboratory and will be taught
      how to operate the new LVES 2. Once the participant is familiar with the basic control
      operations, he/she will receive one on one instruction from a low vision rehabilitation
      therapist on the use of the device with the features and specifications to be tested to
      perform distance, intermediate and near activities. Prior to dispensing either device for a
      2-week home trial evaluation, the patient must demonstrate to the satisfaction of the
      therapist a basic knowledge of and successful operational skill with the device, including an
      understanding that participants are not to attempt to walk or operate a vehicle while wearing
      the device.

      Guided by the AI results, participants will be instructed on the types of activities
      participants should perform at home while using the device. The participant will also take
      part in baseline testing in 1. Facial recognition, 2.Visual motor test, 3. The International
      Reading Speed Texts (IReST) to assess reading performance, and 4. a modified Timed Activity
      of Daily Living (TIADL) performance test. The patient will be called during the 2-week home
      trial period and a Simulator Sickness Questionnaire (SSQ) will be administered. A follow-up
      AI will be administered at the end of the 2-week trial. The participant will return the
      headset to the laboratory after the 2-week trial and will be debriefed on participant's
      experiences and impressions. The 4 tests will be repeated at this visit (Facial recognition,
      Visual motor, IReST and TIADL). None of these procedures are part of or substitute for the
      patient's routine care. Investigators will employ rolling enrollment of participants on
      staggered schedules. Investigators expect to complete the 50th participant with the first
      condition in 22 weeks and then Investigators will start the crossover phase after the 22-week
      washout. Investigators expect to complete both phases with the first 50 patients (less drop
      outs) in year 1. Investigators then repeat the procedure with the next group of 50
      participants in year 2, using systems that include new software features developed in
      response to participant feedback.

      A treatment success is defined as an improvement in functional ability measured with the
      Activity Inventory that exceeds the 95% confidence interval of the estimated baseline measure
      [i.e.,Minimum Clinically Important Difference (MCID)]. Stopping the home trial will not be
      initiated by the investigators, but participants who are experiencing significant simulator
      sickness will be encouraged to stop.

      Participants who stop the home trial prematurely will still be asked to complete the
      post-trial debriefing and the follow-up AI. Since study participation does not substitute for
      the patient's regular clinical care, there is no consequence to the patient for prematurely
      ending study participation.
    

Intervention name(s): Virtual bioptic magnification with large field of view; Full field magnification with small field of view
Intervention type(s): Device; Device
Intervention description(s): The intervention device will have a larger field of vision than the legacy device and the intervention device will also have a virtual bioptic telescope mode not found on the legacy device. The user will be able to adjust the size of the virtual bioptic telescope and the amount of magnification with a touch pad on the side of the head-mounted display (HMD).; Comparison intervention with user-controlled full field magnification with a smaller field size shared by legacy head-mounted devices. User can control amount of magnification
Other intervention name(s): LVES 2; IrisVision; LEGACY
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Intention to treat design; crossover with 22 week washout period between interventions; primary outcome measure is patient-reported function
Masking: Single (Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: age related macular degeneration; visual impairment; virtual reality