ION, the vision-cognition exercise mobile application (Clemson University)

Screenshot of ION's main menu.

ION, The Eye Exercise App

Jessica Lau, Scott Cole, Elizabeth Harruff, James McManus


Millions of Americans suffer from low vision, which inhibits their abilities to complete everyday activities. In vision therapy, patients complete exercises to improve vision-cognition skills. Patient progress in the clinic must be supplemented by at-home vision exercises, but compliance with conventional assigned homework is low because the exercises are not engaging and do not allow the therapist to track patient progress. In response to this problem, we developed the fun and interactive mobile application ION, which engages patients in vision exercises and provides therapists with progress reports of patient performance. Testing on ION showed that it is easy to use by people of all ages; furthermore, users find that ION exercises are more fun than traditional at-home vision exercises.


Vision is generally regarded as the sense on which people most heavily rely throughout life (1). Vision impairment, experienced by millions of Americans (2), can lead to difficulty in completing everyday tasks and therefore loss of independence. For example, vision impairment can reduce the ability to perceive the dynamic driving environment and drive safely.

Our team worked with two occupational therapists, Ms. Jennifer McKay and Ms. Nathalie Drouin, who perform vision rehabilitation at the Greenville Health System’s Roger C. Peace Rehabilitation Hospital. The therapists are focused on addressing the problems with independence that commonly arise when a patient’s vision-cognition skills are damaged or begin to deteriorate.

Currently, the efficacy of vision therapy in improving vision-cognition skills is limited; therapy in the clinic must be supplemented by at-home vision exercises, but patient compliance with prescribed homework is low. Traditional home vision exercises such as pencil push-ups, in which patients attempt to maintain a single fused image of a pencil that is held within a few centimeters of their noses, do not motivate patients. These exercises are not engaging and do not allow the therapist to track patient progress.


Patients need to be motivated to comply more often with their prescribed vision therapy at-home exercises in order to complement therapy performed at the clinic and achieve independence in daily activities such as driving. Our solution was to develop ION, a low-cost mobile application for the Android platform that 1) presents interactive and engaging vision exercises, 2) includes a wide range of exercise settings so that therapy can be customized to individual patients, and 3) generates progress reports so that therapists can track patient compliance and progress with prescribed exercises.


To improve patient compliance with vision therapy, we developed the ION mobile app that offers vision exercises with customizable settings and tracks patient progress. ION was programmed using the open source software Eclipse Integrated Development Environment and Android Software Development Kit.

The app architecture and navigation were designed to be easy to use by all users, including those inexperienced with mobile devices; a diagram of the app organization is presented in Figure 1 below. The main menu allows navigation to the exercises, assessments, progress reports, settings, and about page.

 Algorithm flowchart for ION infrastructure

Figure 1. Algorithm flowchart for ION infrastructure.


Six exercises for the app were based on standard vision therapy exercises and designed through consultation with Ms. Drouin. Two assessments were also designed to test multiple vision-cognition skills at once and provide real-world situational evaluation tools. Sample screenshots of these activities are shown in Figure 2.


  1. Poke the sum is a cognitive summing exercise designed to improve quick cognition skills associated with vision. A simple addition problem appears in the corner of the screen. A button with a number inside will appear in different positions on the screen; the patient must press the button when it contains the answer to the math problem. Available settings for the exercise include exercise duration, size of the buttons, the speed at which buttons appear and disappear, and the difficulty of the math problems.
  2. Word finder is a text scanning exercise designed to improve scanning and perception skills. The patient reads an excerpt of text on the screen and selects each instance of a given word in the shortest amount of time possible. Text size can be adjusted.
  3. Sequence memorization is designed to improve the patient’s ability to quickly interpret visual information, particularly language. A sequence of random letters appears on the screen; after a short time the letters disappear and the patient must type the letters from memory. Settings for the exercise are the length of the sequence and the time it is visible before disappearing.
  4. Direction selection is modeled after Kirschner arrow exercises which help with eye motor control and the ability to respond to visual stimuli. A sequence of directional indicators appears on the screen one at a time, along with buttons in different screen regions (top, bottom, left, right). The patient must select the region button that is indicated by the directional indicator. Settings include indicator type (arrows, letters, shapes) and exercise duration.
  5. Memory cards is a classic short-term visual memory exercise. Cards appear facedown on the screen and the patient taps on them to flip them over. Two cards may be revealed at a time and if they match, they remain visible. The patient must make all cards visible in the smallest number of flips. The number of cards can be adjusted.
  6. Light bulb challenge is a fixation exercise that improves visual attention by requiring simultaneous attention to central and peripheral areas. Buttons appear at random locations on the screen, and a light bulb appears in the center at random times; the patient must only tap the buttons when the light bulb is present. Settings include the speed of button appearance, exercise duration, light bulb size, and button size.


  1. Address book is designed to evaluate the patient’s ability to quickly locate, distinguish, and process information. A list of addresses appears on the screen and a series of questions about the list appears below. The patient must answer all five questions correctly in as short a time as possible.
  2. Driving simulation evaluates the ability to quickly process and respond appropriately to visual stimuli. Images of traffic lights and signs appear one at a time, each for a given amount of time. The patient must select the appropriate action to take in response.
Screenshots of the Direction selection exercise and Driving simulation assessment.

Figure 2. Left: Screenshot of the Direction selection exercise. Right: Screenshot of the Driving simulation assessment.



A wide range of settings for each exercise were designed to allow clinicians and patients to customize therapy regimens to individual needs. The settings can be password-protected, so that clinicians can set exercise difficulty levels that are appropriate for patient progress. A screenshot of ION’s settings page is displayed in Figure 3 below.

Screenshot of the settings menu for Poke the sum.

Figure 3. Screenshot of the settings menu for Poke the sum.


Progress reports

Progress reports were designed so that clinicians can track patient performance; this feedback mechanism, illustrated in Figure 4 below, motivates patients to comply with assigned at-home therapy. The clinician can view daily, weekly, and all-time reports for each exercise and assessment, and can furthermore select to display the average scores, high scores, or the number of repetitions per activity.

Screenshot of a progress report for Direction selection.

Figure 4. Screenshot of a progress report for Direction selection.



Evaluation of ION involved verification and validation procedures to assess if the product was made right and that the right product was made. ION was assessed using verification guidelines established by the Android developer community. Tests were performed that ran each section of the code, assuring that the app is robust to errors and would not crash during use. Additionally, the app was interrupted in multiple ways (e.g. turning power off, switching to a different app) in order to show that it behaves appropriately during these situations.

Validation procedures involved analyzing the interaction of people with ION. Surveys were administered to peer subjects who experienced both traditional at-home vision therapy and the ION app. These surveys showed that the group perceived ION as being more fun than traditional therapy. A second study quizzed both young and elderly subjects on the relevance of ION exercises in vision-cognition therapy. However, no improvement was observed after introduction to ION for 5 minutes, and perhaps a longer learning period was needed to perceive the app’s educational value. A third study with eleven subjects evaluated the ease of use of the ION interface. Young and old people were timed on navigating through the app. T-tests found no statistically significant difference in speed between the users’ initial times and their final times or the developers’ times, indicating that the interface is immediately intuitive to everyone. Additionally, these individuals completed a survey (results below in Figure 5) to rate the ease of use of various aspects of the ION interface, and consistently rated the app 4 or 5 (out of 5).

Graph of usability survey scores.

Figure 5. Subjects consistently rated the ION interface as easy to use. Younger subject rated the interface to be more intuitive than older subjects. Rating options were integers between 1 and 5, with a response of 5 meaning that the subject found the declared aspect of ION easy to use.



Our verification results show that ION is partially optimized for the the consumer market. ION was published recently on the Google Play store and can be found at Further refinement will be necessary to make ION fully compatible with all user devices.

Our validation results indicate ION’s success in the following design goals:

  • ION has an easy-to-use interface. Subjects in both young and elderly populations found ION intuitive and simple to navigate. This signifies our interactive user interface was successfully implemented as intended.
  • Users believe ION to be more fun than traditional vision therapy exercises. Making ION engaging to patients is vital to the patient compliance aim for ION. This result shows us ION is on the right track for replacing traditional vision therapy homework.

Unfortunately, we could not prove ION’s efficacy in improving patients’ education in the usefulness of their vision therapy. We would need to develop a more applicable and lengthy test in order to obtain more accurate results in this field. Future work could include more rigorous testing (larger sample size, longer duration trials) to test ION’s efficacy, particularly in the areas of patient compliance and vision improvement.

In addition to completing verification and validation testing, the team elicited feedback about the app from Ms. Drouin. Overall, her response was very positive, particularly with regards to the interactivity and usability of the app. She said that she liked the app and would use it with her patients. More specifically, she indicated that the app would be easy for both clinicians and their elderly patients to use. Ms. Drouin was pleased with the password-protected settings and varied progress reports that ION offered for her to track her patients’ progress and compliance.

Additionally, Ms. Drouin pointed out that patient impulsiveness (e.g. skipping direction pages instead of reading them) was common to all vision therapy products in her experience; this impulsiveness could contribute to the low educational results attributed to ION.

In summary, ION has shown success in its ease of use and its interactivity and engaging of patients. Furthermore, ION takes advantage of existing mobile device hardware and is thus inexpensive to distribute widely. This vision-cognition exercise app has great potential to replace traditional homework in vision therapy.


1. Sivak, M. (1996). The information that drivers use: is it indeed 90% visual? Perception London, 25, 1081-1090.
2. National Eye Institute. (n.d.) Prevalence of Adult Vision Impairment and Age-Related Diseases in America. Retrieved from


The authors acknowledge Jennifer McKay, OTR/L, Nathalie Drouin OTR/L, CDI, CDRS, and the Clemson University Department of Bioengineering for guidance throughout the design process. The authors would also like to thank the Creative Inquiry program at Clemson University for funding.


Jessica Lau

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