The Arclight and Fundal Reflex Test: Shining the Light on Retinoblastoma

Monday March 18, 2024

Screening children’s eyes with the Fundal “Red” Reflex test is key to early detection of retinoblastoma, but until recently, it was difficult to deliver in many countries.  Dr Andrew Blaikie, ophthalmologist and clinical lead for the Arclight Project at the University of St Andrews, describes the importance of this simple exam, and how the Arclight improves eye health access and outcomes for children with eye cancer around the world.

Two photos side by side. On the left are a Snellen eye chart with large black letters on a white background, a device resembling a pen torch, and an unzipped case containing attachments. On the right, a man holds up an Arclight ophthalmoscope to his right eye. The device emits a bright light. Logos for the University of St Andrews and the Arclight Project are at the bottom of both photos.

Arclight ophthalmoscope, anterior segment loupe, otoscope, visual acuity chart and mobile phone camera attachment.

Early Diagnosis for All Children

Imagine a world where every child, regardless of where they are born, can be screened effectively for eye diseases that could rob them of their sight, or worse, their lives.  This is the vision driving the Arclight Project, an initiative the team based at the University of St Andrews is passionate about.

The goal is simple yet ambitious: to empower healthcare workers around the globe with an affordable, portable device – the Arclight ophthalmoscope – to support early diagnosis and referral for treatment.  This prompt care reduces blindness and death.

Routine use of the fundal “red” reflex test and early intervention are critical in saving children’s sight and lives.  However, the reflex doesn’t always appear ‘red’, especially in individuals with darker eyes, which can lead to confusion and misdiagnosis.

The cost-effective, compact, solar powered Arclight device enables training for inclusive care, and examination of the fundal reflex for early detection of eye diseases, including the childhood eye cancer, retinoblastoma.

The Arclight Project is spearheaded by my team at the University of St Andrews, with a goal rooted in accessibility.  We endeavour to equip healthcare providers across the globe with the means for early diagnosis.

In this blog, I describe the role and variation of the fundal reflex, and the Arclight Project’s aim of democratizing access to eye health diagnosis through widespread use of this highly practical ophthalmoscope.

Two close-up photos side by side. On the left, a child, held by an adult, has a very large growth extending out of the left eye socket. This is labelled as "Late Untreatable Presentation". On the right, another child has a bright white glow in the pupil of the left eye. The other eye has a pale bluish reflex in the pupil. This is labelled "Early Identification: Fundal 'red' Reflex Test with Arclight". Logos of the Arclight Project and University of St Andrews are in the top right corner.

Typical late and untreatable presentation of retinoblastoma in a resource poor setting, compared with early diagnosis with the Fundal Reflex Test using the Arclight.  The difference in colour and brightness between the two eyes on the right suggests the presence of eye disease, prompting referral for further assessment and treatment.

The Fundal Red Reflex Test

Key to early diagnosis is the Fundal Reflex Test, an often-misunderstood aspect of eye health.  Traditionally known as the “Red Reflex”, the fundal reflex test is critical in identifying healthy eyes and those harbouring disease such as retinoblastoma.  It is a fundamental technique in screening for childhood eye disease.

A healthy eye, when examined with an ophthalmoscope, reflects light from the retina in a particular way.  Variations in this reflection can indicate eye conditions such as corneal scars, cataract, or the more serious retinoblastoma.  The potential for early detection facilitates timely treatment that can preserve vision.

The reflex test has become a cornerstone of neonatal and infant eye health in wealthy nations, offering a first glance into a child’s eye health.  By shining a light into the eye and observing the reflection from the back, all grades of healthcare workers can be given the opportunity to detect abnormalities that may indicate eye disorders.

This test is currently routinely recommended as part of post-natal care by health organizations in high income countries, though it is rarely performed in resource poor regions.  Recently however, the World Health Organisation has recommended that the test also be routinely performed on babies and infants born in low resource settings, using the Arclight device.

The Arclight ophthalmoscope therefore emerges as a significant tool, revolutionising access to eye examinations in resource poor settings.  Its design addresses the accessibility and practicality gaps, especially beneficial in regions lacking access to conventional, expensive ophthalmoscopes.

In the following video, can you identify which findings indicate the child needs a specialist referral?  Answers are shown after each image is presented – test begins at 2:00.


Renaming the Red Reflex Test

The “red” reflex appearance varies with ethnicity.  This variation leads to an important need for a more inclusive approach to its name, its interpretation, and the way it is taught.

The traditional “red reflex” test bases its name and “normal” appearances on lighter-skinned European individuals.  This can lead to misinterpretations when examining people with darker eyes, creating confusion when teaching and potentially causing misdiagnosis or unnecessary referrals.

Backing this up, some research has indicated that the fundal reflex can vary in appearance, not limited to red.  This variation is of particular importance in individuals with darker eye colours, where the reflex might appear yellow, orange, or even blue or off-white.  This range or reflex colour underscores the need to re-evaluate the test’s standard colour-based name.

In line with these findings, there is a movement to transition from the term “red reflex” to “fundal ‘red’ reflex”.  This change reflects the diversity of reflex appearances, and also aligns with an anatomically precise description of the test, enhancing clarity and inclusiveness.

Three sets of eyes represent different ethnic groups, each labelled with their respective ethnicity. The “White” eyes show bright red reflex, the “Asian” eyes display a yellowish reflex, and the 'Black' eyes have a creamy-white reflex. These colours are visible in the pupils of the eyes.

The ‘red’ reflex is not red in non-white babies.  All three sets of eyes above show normal fundal reflex, with no variation in appearance between the two eyes.

The Fundal Red Reflex and Photography

Photography plays an essential role in the early detection of retinoblastoma and several other childhood eye diseases.  Educating parents to disable “red-eye-reduction” settings on cameras can unveil crucial early indicators of the condition.  When turned on, these settings can obscure abnormal fundal reflexes.

We advise parents to disable “red-eye-reduction” settings, which could mask the early signs of retinoblastoma.  Similarly, we encourage parents to be cautious about using red-eye correction to remove an unusual white glow from their child’s photograph.

A natural flash photograph could reveal an abnormal fundal reflex – either a white glow or an entirely absent reflex, prompting life-saving medical referral.  Understanding and utilizing these tools effectively requires us to reconsider the traditional terminology used in both medical and photographic contexts.

(A) Original digital image showing left-sided leukocoria and right-sided red-eye. (B) Red-eye reduction software improves the appearance of the right eye. (C) Right pupil is cloned and superimposed on the left eye, resulting in a perfect image.

Figure reprinted from The Lancet, Vol 379: Murphy D, Bishop H, Edgar A. Leukocoria and Retinoblastoma – Pitfalls of the Digital Age? Epub ahead of print. © (2012), with permission from Elsevier.

Illuminating Retinoblastoma for Early Diagnosis

The Arclight device has been developed by the Arclight Project, a social enterprise based at the University of St Andrews in Scotland.  Our team develops and implements a range of affordable solar powered diagnostic eye tools to empower those working in resource poor settings to identify eye disease.

The slim compact design of the Arclight uniquely allows it to be attached to the camera of a mobile phone.  Photos and video of the front and back of the eye, as well as the fundal “red” reflex, can be acquired and used for remote telemedicine diagnosis and monitoring treatment response.  They also support patient education and training students and healthcare workers.

We have developed a strong scientific research base, supporting implementation of the frugal Arclight direct ophthalmoscope as an effective yet low-cost tool to perform the fundal ‘red’ reflex test.

The quick test allows early identification of retinoblastoma in babies and infants who would otherwise present much later to health care professionals.  Worldwide, late referral leads to poorer visual outcomes and death, particularly in low resource settings.

This evidence has recently led the WHO to recommend, for the first time, that all babies receive an eye examination with the Arclight, even those in a low income country.

A collage of five photos. On the left, a compact ophthalmoscope is attached to a silver mobile phone lying on a blue surface. The device has a black body, red button, and a dial, and is secured to the phone's camera with a red elasticated band. The University of St Andrews and Arclight Project logos are at the bottom. The four photos on the right show close-up images of human eyes and the eye’s interior.

Arclight attached to the camera of a mobile phone, and images captured with the ophthalmoscope.

The Arclight Project: Training and Equipping the World

I am an ophthalmologist in NHS Fife and the University of St Andrews, as well as an honorary associate professor at the International Centre of Eye health at the London School of Hygiene and Tropical Medicine.  As the clinical and teaching lead for the Arclight project, along with several NGOs and ministries of health, I have helped to deliver training and equipping workshops in a range of low income countries.

So far, most activity has been in sub Saharan Africa.  This year, several training programmes are being delivered in Asia to establish national community based childhood eye screening programs.  In these workshops, community nurses are taught how to use the Arclight using simulation eyes that demonstrate the clinical signs of cataract and retinoblastoma.

Two photos, side by side. On the left, an unseen person holds an Arclight ophthalmoscope up to their eye, which is almost out of frame. They are looking through the ophthalmoscope at several small cubes with eye diagrams on the front, and round holes in pace of the pupil. In the right photo, papers and multiple black cubes are arranged on a wooden table. Each cube is marked with a white label bearing a number or symbol. Several hands are selecting the objects. Logos of the Arclight Project and the University of St Andrews are seen in both images.

Simulation eyes train then assess participants to confirm correct use of the device, and how to interpret clinical signs for early diagnosis.

Two photos side by side. On the left, a man holds an ophthalmoscope up to his right eye, focusing on two connected simulation eye cubes, which he holds in his outstretched left hand. The second photo is a close up of a hand holding up two attached simulation eyes. The left simulation block shows a white reflex, and the right block shows a red reflex. In the blurred background, several figures are seen observing intently. Logos of the Arclight Project and the University of St Andrews are seen at the top.

Simulation Eyes are effective tools to mimic the appearance of normal and abnormal fundal ‘red’ reflex clinical signs.

Eye Exams for Bhutan’s Babies

As I write, I have just arrived in Thimphu, the capital of Bhutan, a small landlocked kingdom high in the Himalayas.  This program is supported by the US based NGO HCP Cureblindness and the Bhutanese ministry of health.  Together with Dr Dechen Wangmo, Bhutan’s paediatric ophthalmology lead, we will lead a national training programme to establish neonatal and early childhood eye and vision screening.

This week, we aim to train over 100 ophthalmic technicians to use the Arclight to examine eyes, and crucially, on how to deliver their own implementation workshops.

We can deliver interactive and fun workshops using a range of dedicated teaching and assessment tools including handouts, posters, videos, mobile phone applications and simulation eyes.

Two photos side by side. On the left is a printed educational poster titled "Primary Eye Care ATOMS, Malawi 2022". It features various diagrams and images related to eye health, including sections of an eye, eye examination tools, and common eye conditions with illustrations. A folded leaflet version sits beside the poster. On the right, a group of people each hold the same printed materials as seen in the left-hand photo. Logos of the Arclight Project logo and the University of St Andrews are visible in the first photo.

Training Materials explain how to use the Arclight, and the range of diseases that can be diagnosed with the device.

Arclight Training in Action

Training workshops and tools can effectively implement the device so that users get the most out of the Arclight, and maximise benefit to those being screened.  The specialist eye care workers we work with this week will cascade their training to all community nurses in Bhutan who deliver the immunisation programme.

While delivering immunisations, the nurses will perform the fundal “red” reflex test and refer any children they are concerned about to the local eye care team.  The timing of immunisation delivery fits perfectly with the time that identification of childhood eye disease benefits the most.

We hope that within a few months, over 800 devices will be used on a regular basis throughout Bhutan.  This will not just improve the number of referrals, but importantly improve how children with early disease are referred, reducing both blindness and death.

I look forward to updating you later this year on how the Bhutan HCP Cureblindness programme goes, as well as sharing our next initiative in Mongolia.  Orbis, another US based eye care NGO, is already working with the Arclight project to establish national childhood eye screening in the country.

A composite of three photos. On the top left, a room is filled with people sitting at desks with medical equipment spread out before them. In the foreground, a man in a red shirt stands with his back to the camera, his arms raised as he addresses the room. In the bottom left photo, a man holds up a device displaying two simulation eyes. He is pointing to the eye on the left with his other hand. On the right, four people gather around one woman as she shows them the Arclight ophthalmoscope she is holding. Logos for the University of St Andrews and the Arclight Project are visible at the top of the photo.

Trained trainers cascade training to community nurses using validated inter-professional education workshops

Final Words

Numerous published scientific studies evidence the impact of the Arclight device and accompanying educational workshops developed by the project.  They demonstrate the effectiveness and importance of wider knowledge, skill, and disseminating equipment.

Looking forward, there is a promising role for emerging technologies like the Arclight in diagnosing retinoblastoma.  The potential for continuous advancement and accessibility can significantly improve patient outcomes and reduce the impact of this disease globally.

There is a clear call to action for early diagnosis and education in retinoblastoma eye health.  The Arclight project is pivotal in this endeavour, and a collective effort is required to further its reach.  Together, we can ensure that all children, irrespective of their background, have access to necessary eye care, reducing risk to their sight and lives from conditions like retinoblastoma.

If you wish to support our work, please explore the Arclight Project website or email

Dr. Blaikie’s presentation at One Rb World 2021 (12:10).  This “Global Glow” session also includes talks from Megan Webber Co-Founder of Know the Glow (2:05), and Larry Wagh, a Retinoblastoma Parent from Pune, India (23:06).


About the Author

Dr Andrew Blaikie is Senior Lecturer in the Infection and Global Health Division of the School of Medicine, University of St Andrews, and lead for both the Arclight Project and the Digital Diagnostics and Emerging Technologies stream, Mackenzie Institute for Early Diagnosis.

Through education and research collaborations, he also holds honorary professor and lecturer roles at the London School of Hygiene and Tropical Medicine; the Hasanuddin University, Makassar, South Sulawesi, Indonesia; and the University of Rwanda School of Allied Health Sciences.

Dr Blaikie completed a fellowship in paediatric ophthalmology at the Royal Children’s Hospital, Brisbane, Australia, with Professor Glen Gole, a retinoblastoma specialist.

In addition to being a part-time consultant ophthalmologist in NHS Fife, Scotland, Dr Blaikie now works in four main areas: 1) frugal diagnostic tools for low resource settings, 2) inter-professional primary eye care education, 3) Tanzanian endemic optic neuropathy, 4) childhood cerebral visual impairment.

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