A Birmingham-led study has found that AI-powered models match ophthalmologists in diagnosing infectious keratitis, offering promise for global eye care improvements.
Infectious keratitis (IK) is a leading cause of corneal blindness worldwide. This new study finds that deep learning models showed similar levels of accuracy in identifying infection.
In a meta-analysis study published in eClinicalMedicine, Dr Darren Ting from the University of Birmingham conducted a review with a global team of researchers analysing 35 studies that utilised Deep Learning (DL) models to diagnose infectious keratitis.
AI models in the study matched the diagnostic accuracy of ophthalmologists, exhibiting a sensitivity of 89.2% and specificity of 93.2%, compared to ophthalmologists’ 82.2% sensitivity and 89.6% specificity.
The models in the study had analysed a combined total of more than 136 000 corneal images, and the authors say that the results further demonstrate the potential use of artificial intelligence in clinical settings.
Dr Darren Ting, Senior author of the study, Birmingham Health Partners (BHP) Fellow and Consultant Ophthalmologist, University of Birmingham said: “Our study shows that AI has the potential to provide fast, reliable diagnoses, which could revolutionise how we manage corneal infections globally. This is particularly promising for regions where access to specialist eye care is limited, and can help to reduce the burden of preventable blindness worldwide.”
The AI models also proved effective at differentiating between healthy eyes, infected corneas, and the various underlying causes of IK, such as bacterial or fungal infections.
While these results highlight the potential of DL in healthcare, the study’s authors emphasised the need for more diverse data and further external validation to increase the reliability of these models for clinical use.
Infectious keratitis, an inflammation of the cornea, affects millions, particularly in low- and middle-income countries where access to specialist eye care is limited. As AI technology continues to grow and play a pivotal role in medicine, it may soon become a key tool in preventing corneal blindness globally.
Despite South Africa producing a substantial number of trained optometrists, the majority of them work in the private sector and in urban areas. This imbalance leaves rural communities underserved and exacerbates health inequities. Does it make sense for us to use public funds and institutions to train people predominantly for the private sector, ask Dr Haseena Majid and Rene Sparks.
Avoidable blindness caused by uncorrected refractive error (vision problems that requires spectacles or contact lenses) and cataracts can be well managed in the presence of a capable work force that is both accessible and affordable to the public. As such, optometrists are crucial in combating avoidable vision loss. Their expertise in conducting comprehensive eye examinations, diagnosing and managing some eye diseases, prescribing corrective lenses, and providing preventive care is vital for reducing the burden of avoidable blindness.
But the current landscape of optometry services in South Africa reveals significant gaps in both governance and resource allocation.
The distribution of optometrists in South Africa is far from optimal. As of April 2023, there were approximately 4200 registered optometrists and 580 ophthalmologists in the country. While this is a considerable number of people trained to provide primary eye care services, the 6.7% serving the public sector – compared to 93.3% serving the private sector – is simply inadequate and has created stark disparities.
The available evidence points to an urban-rural divide in optometry services, with only around 262 optometrists employed in the public sector nationally, and disproportionately between and within provinces. It means that rural and poor communities, where a significant portion of the population resides, have very limited access to essential eye care services.
Further deepening the disparities in access to essential eye care is the government’s fragmented and inconsistent approach to eye health across provinces, resulting in some areas lacking any public eye care services, while others depend on external providers.
Training misalignment
All of these challenges come against the backdrop of substantial state investment in the training of optometrists. The government funds their training at several universities across the country. However, the majority of these graduates are absorbed into the private sector. In some instances, students trained on state bursaries struggle to get placed in the public sector.
This misalignment highlights a fundamental flaw in how public funds are utilised, with minimal benefit to the broader population that relies on public healthcare. It also contradicts the government’s mandate to provide progressive solutions to improve access to healthcare for all, as enshrined in the Constitution.
These ongoing governance gaps and the inefficient use of state resources also represent significant barriers to achieving health equity in South Africa as expressed in government’s plans for National Health Insurance (NHI). And while the implementation of NHI aims to bring our country closer towards universal health coverage, it is not yet clear whether, and to what extent, vision and eye care services will be included in the envisioned basket of services.
A lack of a clear plan could result in a missed opportunity to integrate optometrists into the primary healthcare system nationally.
What to do
Firstly, there needs to be an urgent reassessment of the costs to train optometrists against the benefits to the broader public. Are we training too many optometrists currently? Could the government initiate engagements with thought leaders and support partners to develop a community service and costing exercise to address the inequity and lack of access to eye health services, and simultaneously address the employment of optometrists within the public health space?
Secondly, the National Department of Health should establish a dedicated directorate for eye health services which should be integrated within provincial health structures. This unit should spearhead a comprehensive data collection system for vision and eye health which can be used to accurately assess needs, allocate resources, and plan effectively.
Calls for such a dedicated directorate have been made through scientific recommendation for more than a decade. But there has been no meaningful response and action from the health department and related decision-making entities.
Thirdly, the principles behind NHI offer a medium-term solution to address the disproportionate distribution of optometrists. Through the establishment of NHI-style public-private partnerships, private sector capacity can be leveraged to serve people who depend on the public sector. Such a public-private partnership will have to have transparency, accountability, and data integrity built into its structures. This will allow provinces and districts to monitor accurate data, and provide feedback that will help shape and improve services.
In summary, the health department stands at a critical juncture, where the systemic imbalances in optometrist distribution and vision care services have now become acute – with people in South Africa paying a very concrete and personal price in the form of avoidable vision loss. Delays in governance processes have historically hampered progress, but the need for swift and informed action is now paramount. The principles of public-private partnership that underlie NHI points to a solution, but the urgency of the crisis means we do not have the time to wait for the full NHI plans to be rolled out – by government’s own admission that will take many years. People losing their eyesight today simply can’t wait that long.
*Majid and Sparks are Global Atlantic fellows for Health Equity in South Africa and advocates on the National Eye Health Advocacy Project led by USAWA for learning and healing, a civil society organisation committed to reforms for health equity and social justice.
Note: Spotlight aims to deepen public understanding of important health issues by publishing a variety of views on its opinion pages. The views expressed in this article are not necessarily shared by the Spotlight editors.
People who wear reusable contact lenses are nearly four times as likely as those wearing daily disposables to develop a rare sight-threatening eye infection, Acanthamoeba keratitis (AK), according to new research. The study, published in Ophthalmology, identifies multiple factors that increase the risk of AK, including reusing lenses or wearing them overnight or in the shower.
AK is a type of microbial keratitis – a condition that results in inflammation of the cornea.
Eye infection from Acanthamoeba. Credit: CDC
Lead author, Professor John Dart (UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust) said: “In recent years we have seen an increase of Acanthamoeba keratitis in the UK and Europe, and while the infection is still rare, it is preventable and warrants a public health response.
“Contact lenses are generally very safe but are associated with a small risk of microbial keratitis, most commonly caused by bacteria, and which is the only sight threatening complication of their use. Given that an estimated 300 million people across the globe wear contact lenses, it is important that people know how to minimise their risks for developing keratitis.”
Contact lens use is now the leading cause of microbial keratitis in patients with otherwise healthy eyes in countries in the global north. While sight loss resulting from microbial keratitis is uncommon, Acanthamoeba, is one of the most severe causes and is responsible for about half of those contact lens users who develop sight loss after keratitis. Avoidable risks are associated with 90% of AK cases. The infection remains rare, affecting fewer than 1 in 20 000 contact lens wearers per year in the UK.
In AK, ,infection by Acanthamoeba, a cyst-forming microorganism, causes the cornea to become painful and inflamed. The most severely affected patients (a quarter of the total) end up with less than 25% of vision or become blind following the disease and face prolonged treatment. Overall, 25% of people affected require corneal transplants to treat the disease or restore vision.
For the study, the researchers recruited over 200 patients of Moorfields Eye Hospital who completed a survey, including 83 people with AK, and compared them with 122 participants who came to eyecare clinics with other conditions, who acted as a control group.
People who wore reusable soft contact lenses (such as monthlies) had 3.8 times the odds of developing AK, compared to people who wore daily disposable lenses. Showering with lenses increased AK risk by 3.3 times, while wearing lenses overnight increased risk by 3.9 times. Among daily disposable wearers, reusing their lenses increased their infection risk. Having had a recent contact lens check with a health professional reduced the risk.
With further analysis, the researchers estimated that 362% of cases in the UK, and potentially in many other countries, could be prevented if people switched from reusable to daily disposable lenses.
A recent study led by Prof Dart found that AK is increasing in prevalence in the UK. By reviewing incidence data from Moorfields Eye Hospital from 1985 to 2016, he and his team found an increase starting in 2000–2003, when there were eight to 10 cases per year, to between 36 and 65 annual cases at the end of the study period.
First author, Associate Professor Nicole Carnt (UNSW, Sydney, UCL Institute of Ophthalmology and Moorfields Eye Hospital) said: “Previous studies have linked AK to wearing contact lenses in hot tubs, swimming pools or lakes, and here we have added showers to that list, underlining that exposure to any water when wearing lenses should be avoided. Public pools and coastal authorities could help reduce this risk by advising against swimming in contact lenses.”
Prof Dart added: “Contact lens packaging should include information on lens safety and risk avoidance, even as simple as ‘no water’ stickers on each case, particularly given that many people buy their lenses online without speaking to a health professional.
“Basic contact lens hygiene measures can go a long way in avoiding infections, such as by thoroughly washing and drying your hands before putting in your lenses.”
