A comprehensive literature review was conducted using databases such as PubMed, Scopus and authoritative clinical websites like the World Health Organization and the Cleveland Clinic. The review aimed to identify existing digital and non-digital eye movement therapy tools, evidence-based treatment approaches for OMD, and key components of efficient therapy design, especially those incorporating gamification and child-centred engagement strategies.

Based on the insights obtained from the literature review and theoretical framework, a paper prototype of the therapy application was designed. The prototype included a sequence of interactive therapy exercises (such as visual tracing and tracking) with three culturally relevant visual storylines. Locally inspired visuals, including South African animals, signs and symbols, were incorporated. The concepts described previously in the theoretical framework were used to ground the paper-prototype. For the development of the paediatric eye movement therapy paper prototype, the Department of Basic Education Rainbow workbook series²³ was used to gain inspiration on eye-catching targets and South African signs and symbols. An internet search for relevant images was also performed. The visuals incorporated into the prototype featured local objects and symbols, animals and everyday scenes. Creating a sense of cultural relevance was intended because this has been shown to enhance motivation, understanding and memory in educational settings. Based on these symbols and a comprehensive literature search, three interactive stories and six practice exercises were created, forming an engaging therapy sequence. Exercises within the application included modified versions of visual tracing and visual tracking. It is intended that the paper prototype will be converted to a digital application in a future study. Although this therapy tool is not intended for use as a standalone treatment for OMD, it may serve as a fun supplement in a structured oculo-motor therapy programme. The Therapy application should be recommended only after a diagnosis of OMD is made by the child’s optometrist. Home-based therapy on a digital platform will allow the optometrist to track therapy progress and provide live feedback, enhancing efficacy of the programme.

Creating the therapy exercises using the national curriculum-based content as inspiration helps the software serve a dual-purpose: giving vision therapy and supporting early learning. This approach reinforces the close connection between vision and learning and responds to the need for accessible, affordable and comprehensive vision care in South Africa’s school health system. When children establish a sense of familiarity with the local symbols and games, it significantly enhances the chances of sustained engagement and improved efficacy. This is also an opportunity for South African children to improve their general knowledge of our country.

A purposive sampling approach was used to select professionals with expertise in paediatrics and binocular vision, ensuring clinical and educationally relevant feedback. Six experts were invited to participate however, only four accepted to participate, resulting in a response rate of 66.7%. These experts were chosen from different provinces in South Africa and other African countries to capture diverse perspectives. All participants are qualified optometrists who serve as lecturers in binocular or paediatric vision and have experience in both clinical practice and academic training. The final paper-prototype was shared with the four field experts to gain user experience feedback and gauge their insight on the therapeutic value of the design.

An online questionnaire was designed using Google Forms to gather expert feedback. The form was distributed electronically, and experts were given 2-weeks to provide a response. The Google Form comprised three parts. Part one of the Google Form included three forced-choice (yes or no)questions was intentionally designed to serve as a baseline measure of the expert’s basic understanding, perceived value, and usability of the prototype. These questions were not meant to generate in-depth insights, but rather to add to the qualitative feedback section that followed.

Part two of the Google Form described three open-ended questions. The first open-ended question, ‘What improvements to the Paper-Based Design would you suggest?’ explored design enhancement and usability, focusing on layout, visual presentation, task clarity and engagement features of the prototype. The second open-ended question was, ‘As a Paediatric Binocular Vision expert, what do you think is important for the researcher to consider when formulating a therapy plan based on digital games?’ This question investigated clinical considerations for digital therapy design, including safety, efficacy, age-appropriateness and the use of evidence-based oculomotor training. And the third question, ‘What key points can you suggest ensuring that the project is designed efficiently to achieve the best possible therapeutic outcome?’, targeted key elements for successful application and achieving desired results, such as tracking mechanisms, task progression, user engagement and alignment with therapeutic goals. The responses from the field experts are presented in Table 1.

The questions in part one and two in the Google Form have not been based on a specific questionnaire; however, it is a compilation of questions adapted from paper prototyping articles available online: Principles of Questionnaire Construction,¹⁸ Interface design survey questions,²⁴ A practical guide to usability questionnaires that evaluate clinicians’ perceptions of health information technology.¹⁹

The forced-choice (yes or no) questions in Part One were used to provide baseline information on experts’ understanding of the prototype. These responses were not analysed statistically but were used to support the qualitative findings from Part Two. The open-ended responses were analysed thematically. Common ideas were grouped into key themes that could be used to further improve the existing design idea.

The short user experience questionnaire²⁵ was the third part of the Google Form. This was designed to assess the usability and engagement of the paper-based prototype (see Figure 1). A semantic-differential scale was used, for example, obstructive versus supportive, boring versus exciting. Experts rate the item on a scale between these opposites.

The circles represent a numerical scale, from 1 to 7. The leftmost circle corresponds to the first adjective (e.g. obstructive). The rightmost circle corresponds to the second adjective (e.g. supportive). Respondents select the circle that best represents their perception.

Responses from the forced choice questions and open-ended questions (part one and two) were recorded and entered onto Microsoft Excel for descriptive analysis. Qualitative responses from open-ended questions were analysed thematically. Similar responses from the experts were categorised and summarised. Results from the short user experience questionnaire (part three) were sent to a statistician and were numerically analysed.

Ethical clearance to conduct this study was obtained from the University of Kwazulu-Natal and Biomedical Research Ethics Committee (No.BREC/00007723/2024).

Saccadic intrusions (involuntary saccades) and impaired initiation of saccades and saccadic oscillation may occur in conditions like Parkinson’s, MS and cerebellar dysfunctions. These movements present as jerky, fluttery, rhythmic and arrhythmic oscillations.²⁶

Children with OMD quickly develop compensatory actions to overcome difficulty with pursuits, saccades and fixation. They may use their finger or pencil to point along lines or adopt a head tilt to assist them overcome the effects of these eye movement disorders. It is therefore important to identify the cause of the OMD through a comprehensive case history from both the parent or guardian and the child. Noting these abnormal eye movements and behavioural cues will assist the optometrist in a timeous diagnosis.

It is well-known that prompt detection of binocular vision disorders is essential. Development and learning are negatively impacted in children when these disorders go undetected. As a result, social and academic success are hindered. It is imperative that any binocular vision disorders are treated prior to initiating eye movement therapy, as untreated conditions may result in diplopia, unstable fixation and compromised smooth pursuits and saccades.

The power of the accommodative system is well known to optometrists. The stamina and strength of this system can be easily overworked when excessive close-up work is done with poor visual hygiene. As a result of our excessive digital demands nowadays, accommodative insufficiency quite commonly shows up in our chairs. Testing usually reveals low accommodative clinical findings, including reduced Visual acuity (VA), intermittent blur and small amounts of against-the-rule astigmatism.²⁷ It is crucial to promptly recognise and treat these signs in addition to the symptoms, such as strain, headaches and tiredness.

Besides the accommodative system, we also note excessive strain on the binocular vision system. Development of BV starts in the brain, and there is valid neurologic evidence that too much screen-time stimulates visual processing more intensely than even the sensory processing systems, this in turn negatively impacts healthy binocular vision development.⁴ Kattouf stated that both convergence excess (high esophoria at near) and convergence insufficiency (high exophoria at near) are commonly seen in her practice because of uncontrolled screen-time among the youth of today. Besides the time spent focusing close-up, it is also the actual distance of the device itself that influences the onset of these BV disorders.

In an Optometry review article by Darko-Takyi and Ebrahim Khan et al. from the University of KwaZulu-Natal,²⁸ it was stated that patients do not always present with only one specific binocular vision or accommodative disorder. Because both these systems are closely interlinked, a vergence anomaly may often be secondary to an accommodative anomaly and vice versa. In addition to the range of tests necessary to make a diagnosis for these non-strabismic conditions, a comprehensive case history would be a clue to revealing the cause of the symptoms experienced.²⁸

Clinical studies reveal that the close viewing distance of handheld digital devices becomes even closer with prolonged use.⁴ The chief complaint of parents who bring their young children in for an eye examination is the observation of how closely the child views a cell phone or tablet. The closer the viewing distance – accompanied by overuse – the more likely an increase in diagnoses of accommodative and binocular vision issues and the visual symptoms that accompany them, says Dr Kattouf.⁴ These binocular vision aspects are to be monitored by the optometrist at the scheduled follow-up sessions. Therapy should only be recommended once the binocular vision and accommodative systems have been evaluated for any BV disorders. If present, these should be treated first. Hence, accommodative and binocular vision parameters must be measured and evaluated in children throughout the therapy programme.

It is well established that myopia progression is linked to an increase in digital device use and screen-time. This has been taken into consideration when designing the paper-prototype. Based on the commonly advised 20-20-20 rule, the therapy sessions within the application are limited to 20 min to minimise screen exposure while maximising therapy outcomes. It is also advisable that the parent or legal guardian is supervising the child’s screen time daily to ensure that good visual hygiene is maintained.

Although excessive screen time is known to be harmful in young children, the type and quality of content also influence outcomes. Prolonged passive use, such as aimless scrolling or extended cartoon viewing, may contribute to myopia development and progression. Interactive screen time that is educational and stimulates critical thinking can benefit children^4,10,29 The paper prototype was designed with this in mind. A creative, interactive method was used to deliver the eye movement therapy exercises.

The COM-B key-behaviour health change model helps understand the aspects influencing health-related behaviour change. It suggests that behaviour is a product of the interaction of the following: capability, opportunity and motivation.³⁰ If children are tasked with something within their capability and understanding, they are more likely to interact well with it.³⁰ Their motivation to persist in the completion of therapy sessions will be sustained if they are able to relate to the ideas, themes and images within the game, such as the currently popular ‘Cocomelon’. Perceived usefulness: ‘The degree to which a person believes that using a particular system would enhance their performance’.³¹ This involves how much children or teachers believe in the technology. If a distinct benefit is noted, participants are more likely to engage with the tool. In the context of this study, if children find the interface challenging to navigate or do not recognise the therapeutic effect, this will discourage them from engaging with it – even if the game design is perfectly designed. This idea comes from the TAM within the Gamification theory.⁸

The design decisions were guided by gamification and behaviour change theory. The main therapeutic goals were to improve fixation, smooth pursuits and saccadic accuracy through structured exercises. Because this research is innovative, the proposed therapy sequence within the application is to be further tested and validated in the follow-up study.

The games will begin with simple exercises and progress to more complex ones. This will improve therapy efficacy as the child will be required to overcome a task to advance to the next. This will result in a sustained advancement in the eye movement skills for participants. This therapy structure will ensure that pursuits and saccades are efficiently trained with simple exercises before presenting more challenging ones. In this way, children are less likely to become agitated or overwhelmed by very difficult activities. The gradual, step-by-step reinforcement of these skills will encourage a maintained engagement with the therapy tool and sustained improvement in pursuits, saccades and fixation.

Feedback on the short user experience feedback questionnaire was positive, particularly regarding simplicity of understanding and use, clarity and supportiveness of the design. Most participants felt that the tool was easy to use and well-structured. However, in the engagement-related categories lower scores were obtained. This suggests that the design will benefit from an enhanced creative and emotional appeal. Improving visual and gamification elements, introducing playful features, or incorporating popular children’s media may help increase excitement and engagement. The design of the application has been developed only to be used as a supplement to an eye movement therapy plan. It may not be used to diagnose the cause of the disorder or be used in isolation. It may only be recommended to a patient once the aetiology of the eye movement disorder is determined by the Optometrist at the comprehensive eye test, and the treatment of the underlying disorder is being managed.

One limitation of this study is the small sample size of experts. A larger expert panel would have allowed for more diverse feedback and valuable critique. It may have also been beneficial to hold a physical focus group meeting with the expert panel, as this would allow for more constructive feedback through actual conversations rather than via a survey.