Impact case study database

Horwood and Riddell’s research has refined the way that clinicians across the different disciplines of ophthalmology, orthoptics and optometry are trained to assess and understand patients’ vision, helping them to ‘work smarter’ and move away from a ‘one size fits all’ approach. Eye care professionals who apply Horwood and Riddell’s approach better understand:

1. that individuals can differ in how they use cue combinations to achieve binocular vision;

2. that ‘normal’ responses can be a lot more variable and apparently poorer than earlier literature research suggests; and

3. that children’s ocular control changes as they get older.

Consequently, clinicians are better equipped to differentiate normal from abnormal binocular vision and interpret test results more accurately. The approach helps clinicians to use individual differences in eye coordination to devise more accurate individualised treatment plans and, importantly, avoid unnecessary treatment. For example, to predict which children are at risk of developing double vision post-operatively or which are unlikely to benefit from wearing glasses.

Influencing orthoptists and optometrists through teaching and learning:

1. Changes to undergraduate curricula

All three UK universities teaching orthoptics (the Universities of Liverpool and Sheffield, and Glasgow Caledonian University) have incorporated Horwood and Riddell’s findings into their undergraduate curricula, teaching them in lectures on typical binocular vision development, accommodative strabismus and AC/A theory, intermittent exotropia and amblyopia. Furthermore, their research has highlighted the importance of defining the population of participants, in terms of whether expert or naïve, in clinical orthoptic research studies. Researchers across the field have adopted this as standard practice as evidenced by the Universities of Sheffield and Liverpool now explicitly teaching students that participants studied in orthoptics and optometry experiments must be naïve to vision science if clinical inferences are to be made. The team’s findings are also taught in the binocular vision modules of many UK undergraduate optometry curricula.

1. Continuing professional development

Between 2017 and 2019, Horwood ran a series of training days, reaching 212 clinical orthoptists across 134 NHS and Irish hospitals (approximately 20% of the UK orthoptist workforce) to introduce techniques based on the University of Reading concept. The primary learning objective was to enable orthoptists in the clinic to determine the cues to depth used by individual patients and then to use this information to guide more effective individual diagnoses and treatment. In a survey by the British and Irish Orthoptic Society (BIOS), 96% (n=212) of all those who signed up to receive training said that Horwood and Riddell’s research had been influential to orthoptic practice in general (65% “very” or “extremely”), and 94% said it had influenced their personal practice (55% “very much” or “extremely”) [E1]. In a 12-month follow up to the training, a University of Reading evaluation showed that 65% of course participants were still using the techniques. Participants noted that the training:

“...has made me more confident in my management of many patients”

“...has really made a difference to my clinical practice”

“The course was extremely useful and hospital appointments reduced” [E2].

1. Providing online resources

Horwood has also produced a number of resources that have been widely disseminated across the optometry profession including an online professional development lecture for UK optometrists focusing on evidence from the University of Reading team showing that certain prescriptions and intensive eye exercises, currently offered by some specialist optometrists, may not be the best approach for the patient. For example, between October 2019 and November 2020, Horwood’s video ‘Prisms: a love/hate relationship’, produced by Optometry Today and approved by the General Optical Council, has been viewed over 2,000 times [E3]. The video was highly recommended by the moderator of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) listserv (the major international discussion forum for senior paediatric ophthalmologists), who commented: “...Professor Horwood goes to the heart of how optometrists and orthoptists differ in their thought processes and approaches. Great video!” [E4]

Influencing ophthalmologists’ practice:

The team’s primary approach to changing clinical practice has been through influencing leading ophthalmologists through invited lectures at major international conferences, who then pass on knowledge to junior team members. It is unusual for orthoptists to directly influence other vision professions but as Horwood and Riddell’s concept is recognised for its more effective approach to treatment, their influence has grown. This is reflected by nominations for prize lectures including:

1. Horwood’s award of the Burian Lecture 2016 (International Orthoptic Association), in response to which the President of the World Society of Pediatric Ophthalmology and Strabismus said: “Our field has suffered from a lack of science and you and your lab are dragging (?pushing) science into the clinician’s office and thus to the patient”… “[the traditional approach] feels like Newtonian physics, which works most of time, but we needed Einstein and others to move us further by disrupting our previous understandings” [E5].

2. Horwood was the first woman and the first orthoptist to be awarded the Beilschowsky Lecture at the International Strabismological Association (ISA) Conference 2018. The introduction to Horwood’s lecture stated: “[the award] acknowledges her numerous novel contributions to the understanding of basic ocular muscle physiology and infant vision development. Her original testing paradigms have contributed to our understanding of accommodation and convergence relationships, and these examination methods are now being applied in clinical and research centers around the world” [E6].

According to the Senior Paediatric Ophthalmologist at The Hospital for Sick Children in Toronto: “[Horwood’s] results have forced the strabismus community to revise decades-long basic science principles that guide clinical practice”… “I personally have benefitted from her innovations, and I have changed some of my testing and treatment of children’s eye muscle problems by applying data from her laboratory. Almost every day I pass on some pearls she has taught us to my residents (registrars) and fellows in the clinic.” [E7]

As a result of influencing leading ophthalmologists’ clinical practice, Horwood and Riddell’s research on binocular vision and concomitant strabismus is also quoted in most current paediatric ophthalmology and orthoptics textbooks (for example: Hoyt and Taylor, Ansons and Davis, Rowe and Kushner) which are recommended to undergraduate orthoptists and trainee ophthalmologists worldwide (evidence from the UK, Netherlands, Canada and Australia). Horwood has also contributed material to two online chapters of the open access American Academy of Ophthalmology Knights Templar Pediatric Ophthalmology Online Education Center, which provides resources for trainee paediatric ophthalmologists worldwide (together totalling 3,422 views between June 2019 and November 2020) [E8].

Professional influence:

As a result of her world-leading research, in 2015 Professor Horwood was appointed as the Research and Innovation Director of BIOS, the professional body for orthoptists. She subsequently led the development of the BIOS curriculum framework – the first since orthoptics became a graduate profession [E9]. The framework lays out which core skills orthoptists need to know and at what level, providing guidance to the three UK universities that offer undergraduate programmes in orthoptics. The framework has also:

• provided the foundation for the development of a European diploma for orthoptists being prepared by the Orthoptistes de Communauteé Européenne

• been used by the Health and Care Professions Council (HCPC) to determine professional training in the UK.

As an expert in the use of photoscreening, Horwood was invited to collaborate in the EU Screen research project, which is evaluating public health screening across 48 countries.

Enabling better care and advice for patients and their parents:

Horwood and Riddell’s early finding – that intermittent misalignment in babies is normal – formed the basis of their 2014 REF impact case study, reporting a change to UK Royal College of Ophthalmologists’ clinical guidelines, whereby infants with suspected strabismus should not be referred before the age of four months. Since then, this recommendation has gone on to influence the American Academy of Ophthalmology’s 2017 clinical guidelines on the management of childhood strabismus, which are used by clinicians around the world [E10]. The recommendation has also become mainstream advice on health and parenting websites, including Bounty, UK; Raising Children, Australia; and Healthline, USA.

Horwood and Riddell’s body of work is proving to be fundamental to understanding many aspects of children’s vision. What is more, it has highlighted that convergence and accommodation sit at the heart of understanding typical and atypical vision development. The overarching concept that variation in cue responses can better explain clinical presentation has rewritten the textbooks, helping to prevent unnecessary treatment and improving treatment targeting. According to the Senior Paediatric Ophthalmologist at The Hospital for Sick Children in Toronto, who sees approximately 3,000 children each year from across Canada, the widespread impact of Horwood and Riddell’s research across the associated eye care professions is that: “It has changed how strabismus experts use glasses and prisms to treat eye muscle conditions. In addition, the surgery planning now requires a more detailed analysis to predict the impact of the surgery on both convergence and accommodation links.”

“It is difficult to determine the number of practitioners and individuals world-wide who have benefitted from and been influenced by her innovations. However, given her international reputation, among those who have been exposed to her work… [it is] at least 5,000-6,000 strabismus specialists, several hundred orthoptists, as well as several thousand optometrists. In turn, their cumulative patient contact would include hundreds of thousands children and adults per year.” [E7]