It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, April 23, 2025
New era of aid cuts and conflict threatens educational lifeline of youngest learners
Latest figures show international aid for early years education was already falling before cuts to USAID stripped a further $745 million from the global education aid budget.
A sharp drop in aid for pre-primary education may be the first sign that the international community is turning its back on the world’s most vulnerable children amid wider economic strain, a new report warns.
The annual donor ‘scorecard’, produced by researchers at the University of Cambridge for the charity Theirworld, reveals that the proportion of global education aid being committed to early childhood education – which was already well below international targets – has started to fall. The report’s authors warn that the true picture could be far worse, as the latest available data are from 2023: the beginning of what they describe as a new era of “cuts and conflict”.
The scorecard tracks how much international aid is being spent on education for the critical early years, up to age five. The researchers expected to see signs of a post-pandemic recovery in the latest figures, but instead found a decline: between 2022 and 2023, pre-primary education aid fell by $20 million, to $250 million in total.
As the report notes, however, these figures precede the Trump administration’s recent decision to axe 99% of basic education funding through the United States Agency for International Development, stripping $745 million from the global education aid budget – which covers pre-primary funding as well as other areas.
Britain and Switzerland have also scaled back their spending commitments. “There are signs that others might be moving in the same downward spiral,” the report notes. “While the effects of the latest cuts are yet to be felt, it is apparent that the aid landscape is rapidly changing.”
Among numerous findings, the report highlights the scale of inequalities between young learners in the world’s richest and poorest nations.
In countries where pre-primary education aid is most urgently needed – such as Sudan and the Syrian Arab Republic – less than 20 US cents of aid were spent per pre-primary aged child in 2023. As a comparator, average per-child spend in the mostly high income member states of the Organisation for Economic Co-operation and Development (OECD) was just under $8,000.
Professor Pauline Rose, Director of the Research for Equitable Access and Learning (REAL) Centre at the University of Cambridge, said: “This information comes from the very start of a period of both severe aid cuts, and escalating conflict in places like Gaza, Sudan and Ukraine.”
“The cost of these dual effects for children is likely to be immense. We know that the poorest and most marginalised children already lack access to crucial early childhood learning opportunities. That crisis will now deepen, if those with the power to save and change lives continue to turn inward instead.”
The case for investing in pre-primary education is well established. Research has consistently shown that the early years are a critical developmental window, influencing children’s future learning, health and life chances. The World Bank has identified early childhood programmes as among the most effective investments governments can make to improve long-term outcomes.
Yet globally, provision remains limited. According to UNICEF, only 40% of children can access early childhood education and in parts of Africa and the Middle East the figure is closer to 25%. Theirworld has long called for 10% of education aid to be allocated to the early years to rectify this. The target was endorsed by 147 UN member states in the 2022 Tashkent Declaration.
In raw terms, the total aid spent on pre-primary education in 2023 was the second highest since records began. However, the $250 million disbursed represented just 1.2% of global education aid, down from 1.4% the year before, and drifting further from the 10% target. The report suggests this may be a sign of worse to come, as global aid spending overall also fell by 0.6%.
The limited funding for pre-primary education is also highly concentrated. Over half went to just five countries: Tanzania, Rwanda, Jordan, Bangladesh and Ethiopia. Five of the 26 countries classified as “low income” received nothing, and of the remaining 21 countries only Rwanda received support worth more than $5 per pre-primary aged child. In Palestine, aid per pre-primary aged child equated to just $1.79, and in Ukraine it was just 14 cents.
Echoing previous reports, the new scorecard highlights the fragility of a funding landscape in which aid tends to be concentrated in the hands of a few donors. The World Bank accounted for 57.3% of all early childhood education aid in 2023, but also cut its spending by 17.7%. EU institutions and UNICEF – who together accounted for much of the remainder – also reduced their spending allocations.
UNICEF and the Global Partnership for Education were the only major donors who met the 10% target, but even UNICEF’s support declined to the lowest level since 2017. “Given that UNICEF is an organisation dedicated to children, this decrease is a cause for concern,” Dr Asma Zubairi, co-author of the report, said.
With the United States in particular effectively abandoning education aid, Rose said that other major donors should urgently reaffirm their commitments and ring-fence support for the pre-primary years.
She added that this could be achieved, even in the context of broader economic pressures, by reallocating funds from post-secondary education. In 2023, donors spent 24 times more on aid for post-secondary education than on pre-primary, much of which went to students from low-income countries studying in the donor nations.
“Higher education clearly matters, but the balance is wrong,” Rose said. “We need to be much smarter about whom we fund and how. Instead on focusing on young people who make it to university, we should be targeting those children who never make it out of the starting blocks.”
The first clinical trial to test whether adults allergic to peanuts can be desensitised has shown great success with two thirds of the cohort consuming the equivalent of five peanuts without reacting.
The Grown Up Peanut Immunotherapy (GUPI) trial is the first study entirely in adults with severe allergy to test whether daily doses of peanuts taken under strict supervision can be safely tolerated.
The approach, known as oral immunotherapy, has seen success in trials in infants and children worldwide. The findings of the first trial in an exclusive adult cohort has been published today in the journal Allergy by a research team from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust. The study is funded by the National Institute for Health and Care Research (NIHR) Research for Patient Benefit Programme.
Chief InvestigatorProfessor Stephen Till, Professor of Allergy at King’s College London, said: “Constant fear of life-threatening reactions place a huge burden on people with peanut allergy. The only way to manage a peanut allergy is strict avoidance and treatment of allergic reactions, including with adrenaline. Although peanut immunotherapy is known to be effective in children, this trial provides preliminary evidence that adults can also be desensitised and that this improves quality of life. The average tolerated dose of peanuts increased 100-fold over the course of the trial.”
The Phase II trial recruited twenty-one adults between 18 and 40 with a clinical diagnosis of peanut allergy at Guy’s and St Thomas’ NHS Foundation Trust. Allergy was confirmed via skin prick test, blood test and then an oral food challenge.
In a clinical setting, participants received the first dose of 0.8mg peanut flour mixed in with food, then 1.5 mg 30 minutes later followed by 3mg a further 30 minutes later.
Participants who tolerated 1.5mg or 3mg of peanut flour continued on a daily dose at home for 2 weeks. This is the equivalent of 0.5-1% of a whole peanut.
Then participants returned at 2-weekly intervals for supervised doses of more peanut protein, increasing from 6mg (around 1/40th of a whole peanut) to 1g (four whole peanuts). If participants could tolerate 50-100mg of peanut protein, participants were switched to eating whole peanuts, peanut butter or peanut products, with the first dose being under supervision of the clinical team.
Once participants achieved a daily dose of 1g they remained on this dose for at least four weeks before undergoing a double‐blind placebo‐controlled food challenge. This involved being given increasing doses of either peanut or placebo (dummy) on separate days under close supervision to test their tolerance. Participants then continued daily dosing for at least three months before exiting the trial as well as the option of continuing post-study.
Results showed that 67% of participants were able to consume at least 1.4g peanut protein – the equivalent of five peanuts – without reacting. Participants of the trial then could consume peanuts every day at home to remain desensitised.
Professor Till said: “We are very pleased with the results. The efficacy rate is broadly in line with peanut oral immunotherapy trials in children. The next stage of the research will be confirming this in larger trials, and also identifying the group of adult patients who would most likely benefit from oral immunotherapy, and see whether it can lead to long-term tolerance in this age group.”
Lead author specialist Allergy Dietitian Hannah Hunter from Guy’s and St Thomas’ NHS Foundation Trust said: “Living with peanut allergy is a huge burden due to the need for constant vigilance and the risk of accidental exposures. Everyday situations such as eating in restaurants and social events are anxiety provoking and our patients tell us that the condition also affects travel choices and career options. We found that quality of life significantly improved after oral immunotherapy and fear of food also decreased. Many participants who completed the trial told us that the treatment had been life-changing and they were no longer living in fear.”
Chris, 28, took part in the trial. He was diagnosed with a peanut allergy as a baby and jumped at the chance of taking part in the trial.
He said: “I’m so proud to have been part of this trial and so happy to say that I used to be allergic to peanuts but thanks to this trial, this is no longer a concern. Me and my family were always anxious that even a trace of peanut could be life-threatening. The trial was an interesting experience because all of my life I had associated the taste and smell of peanuts with fear and death. I started with a small amount of peanut flour with yoghurt and by the end of the trial I could eat four peanuts in one sitting. Now, I have four peanuts every day with my breakfast to maintain my immunity. Before, a tiny mistake could have life-threatening impacts but now I don’t have the fear that I might collapse and die from eating a takeaway.”
Journal
Allergy
Article Publication Date
24-Apr-2025
London’s low emission zones save lives and money, new study finds
18.5% reduction in sick leave following LEZ implementation
10.2% decrease in respiratory issues
Annual public health savings of over £37 million
New research from the University of Bath has revealed that Greater London's clean air policies—the Low Emission Zone (LEZ) and the Ultra Low Emission Zone (ULEZ) are not only improving the city’s environment but are also delivering significant measurable public health and economic benefits.
The study, published in the Journal of Economic Behavior and Organization which analysed over a decade of data from Greater London and Central London, found that the introduction of the LEZ in 2008 and the ULEZ in 2019 significantly reduced harmful pollutants like nitrogen dioxide (NO₂) and particulate matter (PM10), resulting in a dramatic drop in sick leave in Greater London, and improved mental well-being and substantial cost savings.
Key findings in Greater London compared to areas in England without low emission zones:
18.5% reduction in sick leave following LEZ implementation
6.8% drop in the incidence of health problems
10.2% decrease in respiratory issues
Reported improvements in happiness, life satisfaction, and reduced anxiety.
Annual public health savings of over £37 million, driven by fewer respiratory illnesses and reduced job absenteeism thanks to low emission zones.
Dr Habtamu Beshir, who led the research at the University of Bath and is now based at UCL said: “Our work shows that clean air policy is smart policy. It protects health, saves money, and enhances quality of life - making the case for clean air initiatives stronger than ever.”
The study employed a quasi-experimental method, analysing changes in affected and unaffected areas before and after policy rollout. The data shows that when LEZ was tightened in Phase 2 (July 2008), NO₂ levels dropped by 5.8% and PM10 by 9.7%. ULEZ, the strictest policy of its kind globally, delivered even greater reductions—NO₂ down 21% and PM10 down 15% estimated by comparing Central London to other areas outside Greater London, before and after ULEZ was introduced.
The research adds weight to the growing international body of evidence linking air pollution control with public health and economic outcomes.
Professor Eleonora Fichera added: “With the World Health Organization estimating 4.2 million premature deaths globally each year due to air pollution, these findings signal the urgent need for similar transport policies in other major cities not just in the UK but around the world.”
For more information, please contact: Rebecca Tanswell University of Bath Press Office Tel: 01225 386319 Email: rlt54@bath.ac.uk
About the University of Bath The University of Bath is one of the UK’s leading universities, recognized for high-impact research, excellence in education, an outstanding student experience, and strong graduate prospects.
Ranked in the top 10 of all the UK’s major university guides.
Among the world’s top 10% of universities, placed 150th in the QS World University Rankings 2025.
Rated in the world’s top 10 universities for sport (QS World University Rankings by Subject 2024).
Research from Bath addresses critical global challenges, fostering low-carbon living, positive digital futures, and improved health and wellbeing. Learn more about our Research with Impact: https://www.bath.ac.uk/campaigns/research-with-impact/
The iconic pea plant experiments of Gregor Mendel laid the foundations for the science of genetics.
Now 160 years on, an international research collaboration has used genomics, bioinformatics and genetics to map the diversity of a globally important pea collection – revealing secrets behind the traits that Mendel made famous and uncovering agriculturally useful genetic diversity on an unprecedented scale.
The new set of gene bank and genomic resources available to researchers and breeders worldwide could revolutionise pea breeding and research into this environmentally important legume crop, say the authors of a new study.
“Our collaboration has created a genomic resource of extraordinary depth and breadth, including the whole genome sequence data for pea,” said one of the co-corresponding authors Dr Noam Chayut, who manages the Germplasm Resource Unit (GRU) at the John Innes Centre.
“We already have researchers and multi-national companies ordering seeds corresponding to the novel genomic resources, which will revolutionise how companies breed peas, and how scientists study them, across the world.”
The research, which appears in the journal Nature, is built on a collaboration between the John Innes Centre (JIC) and the Chinese Academy of Agricultural Sciences (CAAS), together with other research groups in China, the UK, USA and France.
This landmark study comes at a time when peas and other legumes are being called upon as a source of plant protein, and as sustainable crops which can fix their own nitrogen. This means pea and other legume crops need less chemical fertiliser to grow, potentially lowering land and river pollution.
“Mendel was not just interested in pea because it was a perfect model organism, although it was,” said Dr Chayut. “It was also an important crop that he wanted to improve by solving problems that were facing gardeners and growers at the time.
“Similarly, this study not only shines a light on Mendel’s fundamental discoveries, but it also opens the route to growing pea in many parts of the world, including the UK. Pea is a crop which can deliver a sustainable source of plant-based protein and has a major role to play in the future of farming.”
How did researchers unlock the genomes of a global pea collection?
Researchers selected a representative sample of around 700 pea accessions from the collection of 3,500, assembled from around the world over decades and maintained at the GRU, a national capability funded by BBSRC.
This generated 62 terabytes of raw data, comprising 25.6 trillion pieces of information which, if printed out, would cover 3.6 billion sheets of A4 paper.
With this data, the team created a global genomic map of pea, from the highly bred and cultivated pea, through to locally adapted varieties called landraces, and wild relatives.
Using this map and a technique called Genome Wide Association Studies, they identified regions of the genomes that corresponded to valuable trait variation. The research has connected more than 70 agronomic traits to corresponding genomic locations. The many different genetic markers at each of these locations can be used to accelerate pea improvement.
Looking forward, the new resource, coupled with other modern technologies such as gene editing, long-read DNA and RNA sequencing, will open unprecedented opportunities for novel gene discovery. It will also pave the way for more predictive breeding – such as using AI models which can select combinations of genes to deliver better yielding, disease resistant, agronomically viable pea plants.
Mendel’s enduring legacy
Mendel’s work on peas was described by the science historian Allan Franklin as “the best experiments ever done.”
Working in the early days of cell theory, and before genetics was known, he focused on seven traits: pea seed shape (round or wrinkled), pea seed colour (green or yellow), pod shape (constricted or inflated), pod colour (green or yellow), flower colour (purple or white), plant size (tall or dwarf) and position of flowers (axial or terminal).
Over many years of experiments, involving thousands of plants, he established fundamental rules of inheritance, how characteristics are passed down through the generations, and single-handedly laid the groundwork for the science of genetics.
The novel genomic tools created by this modern scientific collaboration are being used to revisit these classic experiments, shedding light on the genetics underpinning Mendelian traits. For the trait of flower colour the team found an unusual type of naturally occurring mutation which restores the purple colour to white flowered peas.
The team also discovered a mutation that results in the yellow pod trait, which is of great interest to academics as it is the consequence of an interaction between two adjacent genes.
Mendel discovered what we now call the laws of inheritance without knowing what a gene was,” said one of the lead authors of the study, Professor Shifeng Cheng of the CAAS Agricultural Genomics Institute at Shenzhen. “Today using modern tools, we can see the exact genes and the precise mutations that he unknowingly tracked.”
Mendel scholar Professor Noel Ellis, co-corresponding author of the study and researcher at the John Innes Centre, commented: “In addition to the practical utility of these accessions and associated data to breeders, the resources are of great value for academics and teachers of genetics because our study gives an up-to-date description of Mendel’s variants. The data is available, and the pea lines can be ordered – we hope that academics will access these resources freely.”
Cong Feng, a graduate student in Professor Cheng’s team and co-first author of the paper, said: “Genome-wide association studies (GWAS) and haplotype analysis proved to be incredibly powerful tools. We were thrilled to uncover sequence-level insights into all seven of Mendel’s classical traits.”
Mei Jiang, a student and co-first author, added: “This project deepened my fascination with peas, genetics, and the legacy of Mendel. It has become both a scientific and personal journey.”
Dr Julie Hofer, another co-first author on the paper and postdoc at the John Innes Centre, said: “For years, the genetic basis of pod color resisted explanation despite extensive research. Our discovery highlights the subtle ways that genomic structure can influence gene function at a transcriptional level.”
The study exemplifies the importance of collaboration in science, concluded Dr Chayut: “We can achieve so much more when we work together.”
Other contributors to the study were:
INRAE Institute of Plant Sciences at Paris-Saclay, Gif-sur-Yvette, France
Paleogenomics Laboratory, INRAE, Clermont-Ferrand, France.
INRAE UMR1347-Agroecologie pôle GEAPSI, DIJON Cedex, France.
EMBL-EBI, European Molecular Biology Laboratory, Hinxton, UK
Department of Plant Pathology, University of Minnesota, St Paul, MN, USA
State Key Laboratory of Wheat Improvement, at Peking University Beijing, China.
Genomic and Genetic Insights into Mendel’s Pea Genes appears in Nature.
Even though microbial keratitis is a preventable cause of blindness, it's a complex infection to treat, and many patients have lasting vision impairment.
Previous studies have identified several risk factors for reduced vision after treatment, including delays in symptom onset, longer duration of symptoms and existing eye disease.
However, these studies were restricted to one geographic area or a single type of organism that causes the infection.
In a study published in Ophthalmology, physicians followed 562 patients in the United States and India over a three-month period to identify risk factors that could be easily managed with early intervention.
Maria A. Woodward, M.D., an associate professor of ophthalmology and visual sciences and a member of the Institute for Healthcare Policy and Innovation, answers questions about what causes microbial keratitis, symptoms and preventative measures.
What are the common causes for microbial keratitis?
Woodward: We are surrounded by microorganisms, including Staphylococcus aureus, Streptococcusand fungi, which can get into our eyes through small injuries.
This is a common outcome in patients who do not have good contact lens hygiene or have an underlying eye condition that makes them prone to infections.
Although we don’t know the prevalence rates in the U.S., worldwide it affects over 2 million people per year.
What are symptoms of microbial keratitis?
Woodward: It depends on the infection. Some types of bacterial infections can progress incredibly quickly while fungal infections are slower.
Early symptoms include eye pain, severe eye redness and blurry vision. Some patients also experience light sensitivity.
Unfortunately, many ignore these warning signs and continue to use contact lenses, which can make the problem worse.
If left untreated, the condition causes eye pain and can ultimately penetrate deeper into the eye resulting in scarring and vision loss.
What factors affect treatment for microbial keratitis?
Woodward: The majority of infections in the U.S. are usually treated with antibiotic eye drops.
In our study, we found that if a patient had reduced vision or waited for symptoms to worsen, treatments did not work as well.
Interestingly, we saw that patients in the U.S. who wore contact lenses had slightly better outcomes.
We suspect that their physicians could easily identify what kind of infections are associated with wearing lenses and were able to treat them earlier.
In India, we observed a similar effect in patients with a history of eye trauma.
In rural areas, it's common for people to get something in their eye that can lead to an infection.
It’s possible that the physicians there knew what kind of infection they might have, given their environment and history, and were able to administer treatments sooner.
What future directions are you excited to pursue?
Woodward: Although this work doesn't represent everyone globally, we found some commonalities regardless of where the participants were from.
It is important to expand these studies to include factors such as access to medications and adherence to eyedrop regimens.
As part of this work, we took serial photographs of patients over time to monitor how their eye characteristics change over time.
We can use this to help physicians distinguish between mild and severe cases and treat patients effectively.
Fear of vision loss may deter some patients from undergoing necessary cataract surgery, according to a newly published study. Cataracts are the leading cause of reversible blindness, and surgery remains the only effective treatment.
The research was led by Lisa Kelly, MD, a Taylor Asbury-endowed professor-educator and director of medical student education in the Department of Ophthalmology at the University of Cincinnati College of Medicine. Kelly also serves as medical director of UC eye clinics. The study’s corresponding author was Samantha Hu, a fourth-year medical student. Stephanie Wey, MD, a former UC resident, and Rainier Yono, a third-year medical student, also contributed.
The research team surveyed 42 patients at Hoxworth Eye Clinic, the training site for UC’s ophthalmology residents located near UC Medical Center. The study explored a possible link between health literacy and fear surrounding cataract surgery.
“We hypothesized that patients with lower health literacy would fear surgery more, especially the risk of vision loss,” said Hu. “But our findings didn’t support that.”
Cataracts develop when proteins in the eye’s natural lens break down and clump together, leading to blurry or dimmed vision. Because the condition is most commonly age-related, those surveyed were all 50 and older. Sixty percent reported a yearly income below $50,000.
Study findings
Among those surveyed, 36% reported fear of cataract surgery, and more than half of those specifically feared it would lead to vision loss. However, researchers found no correlation between this fear and a patient’s health literacy level.
“We found patients who would benefit from surgery reasonably understood the procedure after we educated them,” Kelly said. “But even with clear explanations, sometimes their fear persisted.”
Hu noted that simply providing more information wasn’t always helpful. “Overloading patients with data doesn’t necessarily ease their concerns,” she said.
Instead, the study pointed to the importance of open communication.
“Yes, patient education matters, but it’s not always sufficient,” said Kelly. “What’s equally important is building relationships and trust to help patients overcome fear.”
Hu said the findings emphasize how much patients rely on their physicians to guide them to medical decisions based on their individual needs.
“It underscores the trust patients place in their doctors — and the need for physicians to truly understand their patient population,” said Hu.
Kelly added, “It’s a reminder that our patients are people with real fears. Our role is to partner with them in their health care.”
Moving forward, researchers are likely to delve deeper into patients’ fear around cataract surgery and how physicians can further strengthen doctor-patient relationships.
Path to residency
Hu is part of the UC College of Medicine’s Class of 2025. She is originally from Greenwood Village, Colorado, a suburb of Denver.
As Hu became more focused on pursuing the ophthalmology specialty, she said she reached out to Kelly about taking part in research and joined the study in her second year of medical school for the data gathering process.
Hu said she was intrigued by this study because of her interest in the social determinants of health, the economic and social conditions that influence differences in people’s health. “Sam and I spent a lot of one-on-one time together as she worked on this research project,” said Kelly. “I got to know her well.”
The results of the study were first presented at a medical conference last year and likely helped Hu stand out in the competitive residency matching process.
“Engaging with a scholarly question in research like this better positions medical students to take a critical look at the literature,” Kelly said.
After she graduates this spring, Hu will begin her ophthalmology residency at Loyola University Chicago.
Journal
Journal of Clinical Ophthalmology
Method of Research
Survey
Subject of Research
People
Article Title
Fear of Cataract Surgery and Vision Loss: The Effects of Health Literacy and Patient Comprehension at an Academic Hospital-Based Eye Clinic
Scientists trick the eye into seeing new color ‘olo’
UC Berkeley scientists created a new platform called “Oz” that directly controls up to 1,000 photoreceptors in the eye at once, providing new insight into the nature of human sight and vision loss
UC Berkeley scientists created a new platform called “Oz” that directly controls up to 1,000 photoreceptors in the eye at once, providing new insight into the nature of human sight and vision loss. In this photo, Hannah Doyle, a graduate student at UC Berkeley, operates the Oz system from a laptop.
In Frank Baum’s original novel The Wonderful Wizard of Oz, the Emerald City is said to be such a brilliant shade of green that visitors must wear green-tinted glasses to protect their eyes from “the brightness and glory” of the city.
The glasses are one of the wizard’s many deceits; the city viewed through green-tinted glasses would, of course, only look more green.
But using a new technique called “Oz,” scientists at the University of California, Berkeley, have found a way to manipulate the human eye into seeing a brand-new color — a blue-green color of unparalleled saturation that the research team has named “olo.”
“It was like a profoundly saturated teal … the most saturated natural color was just pale by comparison,” said Austin Roorda, a professor of optometry and vision science at UC Berkeley’s Herbert Wertheim School of Optometry & Vision Science, and one of the creators of Oz.
Oz works by using tiny doses of laser light to individually control up to 1,000 photoreceptors in the eye at one time. Using Oz, the team is able to show people not only a green more stunning than anything in nature, but also other colors, lines, moving dots and images of babies and fish.
The platform could also be used to answer basic questions about human sight and vision loss.
“We chose Oz to be the name because it was like we were going on a journey to the land of Oz to see this brilliant color that we'd never seen before,” said James Carl Fong, a doctoral student in electrical engineering and computer sciences (EECS) at UC Berkeley.
“We’ve created a system that can track, target and stimulate photoreceptor cells with such high precision that we can now answer very basic, but also very thought-provoking, questions about the nature of human color vision,” Fong said. “It gives us a way to study the human retina at a new scale that has never been possible in practice.”
The Oz technique is described in a new study published last week in the journal Science Advances. The work was funded in part by federal grants from the National Institutes of Health and the Air Force Office of Scientific Research.
Untapped photoreceptors
Humans are able to see in color thanks to three different types of photoreceptor “cone” cells embedded in the retina. Each type of cone is sensitive to different wavelengths of light: S cones detect shorter, bluer wavelengths;, M cones detect medium, greenish wavelengths; and L cones detect longer, reddish wavelengths.
However, due to an evolutionary quirk, the light wavelengths that activate the M and L cones are almost entirely overlapping. This means that 85% of the light that activates M cones also activates L cones.
“There's no wavelength in the world that can stimulate only the M cone,” said study senior author Ren Ng, a professor of EECS at UC Berkeley, “I began wondering what it would look like if you could just stimulate all the M cone cells. Would it be like the greenest green you've ever seen?”
To find out, Ng teamed up with Roorda, who had created a technology that used tiny microdoses of laser light to target and activate individual photoreceptors. Roorda calls the technology “a microscope for looking at the retina,” and it is already being used by ophthalmologists to study eye disease.
But for a human to actually perceive a whole new color, Ng and Roorda would need to find a way to activate not just one cone cell, but thousands of them.
A movie screen the size of a fingernail
Fong first started working on the Oz project in 2018 as an undergraduate engineering student, and has created much of the complex software needed to translate images and colors into thousands of tiny laser pulses directed at the human retina.
“I joined after meeting this other student who was working with Ren, who told me that they were shooting lasers into people's eyes to make them see impossible colors,’” Fong said.
For Oz to work, first you need a map of the unique arrangement of the S, M and L cone cells on an individual’s retina. To get these maps, the researchers collaborated with Ramkumar Sabesan and Vimal Prahbhu Pandiyan at the University of Washington, who have developed an optical system that can image the human retina and identify each cone cell.
With an individual’s cone map in hand, the Oz system can be programmed to rapidly scan a laser beam over a small patch of the retina, delivering tiny pulses of energy when the beam reaches a cone that it wants to activate, and otherwise staying off.
The laser beam is just one color — the same hue as a green laser pointer — but by activating a combination of S, M and L cone cells, it can trick the eye into seeing images in full technicolor. Or, by primarily activating the M cone cells, Oz can show people the color olo.
“If you look at your index fingernail at arm's length, that's about the size of the display,” said Roorda. “But if we could, we would have filled the entire visual space like an IMAX.”
The ‘wow’ experience
Hannah Doyle, a doctoral student in EECS and co-lead author of the paper, designed and ran the human experiments with Oz. Five human subjects got the chance to see the color olo, including Roorda and Ng, who were aware of the purpose of the study, but not the specifics of what they would see.
In one experiment, Doyle asked the participants to compare olo to other colors. They described it as blue-green or peacock green, and reported that it was much more saturated than the nearest monochromatic color.
“The most saturated colors you can experience in nature are the monochromatic ones. Light from a green laser pointer is one example,” Roorda said. “When I pinned olo up against other monochromatic light, I really had that ‘wow’ experience.”
Doyle also tried “jittering” the Oz laser, directing it ever-so-slightly off target so the light pulses hit random cones rather than only M cones. The participants immediately stopped seeing olo and started seeing the regular green of the laser.
“I wasn't a subject for this paper, but I've seen olo since, and it's very striking. You know you're looking at something very blue-green,” Doyle said. “When the laser gets jittered, the normal color of the laser almost looks like yellow because the difference is so stark.”
Probing the nature of color vision
Oz isn’t just useful for projecting tiny movies into the eye. The research team is already finding ways to use the technique to study eye disease and vision loss.
“Many diseases that cause visual impairment involve lost cone cells,” Doyle said. “One application that I'm exploring now is to use this cone by cone activation to simulate cone loss in healthy subjects.”
They are also exploring whether Oz could help people with color blindness to see all the colors of the rainbow, or if the technique could be used to allow humans to see in tetrachromatic color, as if they had four sets of cone cells.
It may also help answer more fundamental questions about how the brain makes sense of the complex world around us.
“We found that we can recreate a normal visual experience just by manipulating the cells — not by casting an image, but just by stimulating the photoreceptors. And we found that we can also expand that visual experience, which we did with olo,” Roorda said. “It’s still a mystery whether, if you expand the signals or generate new sensory inputs, will the brain be able to make sense of them and appreciate them? And, you know, I like to believe that it can. I think that the human brain is this really remarkable organ that does a great job of making sense of inputs, existing or even new.”
Additional authors of the study include Congli Wang, Alexandra E. Boehm, Sophie R. Herbeck, Brian P. Schmidt, Pavan Tiruveedhula, John E. Vanston and William S. Tuten of UC Berkeley. This work was supported by a Hellman Fellowship, FHL Vive Center Seed Grant, Air Force Office of Scientific Research grants (FA9550-20-1-0195, FA9550-21-1-0230), National Institutes of Health grant (R01EY023591, R01EY029710, U01EY032055) and a Burroughs Wellcome Fund Career Award at the Scientific Interface.
UC Berkeley scientists created a new platform called “Oz” that directly controls up to 1,000 photoreceptors in the eye at once, providing new insight into the nature of human sight and vision loss. In this photo, Oz creator Austin Roorda, a professor of optometry and vision science at UC Berkeley, demonstrates what it looks like to be part of the Oz experiment.
