Tube shunt surgery is a common surgical approach to treating glaucoma. The procedure aims to reduce the eye pressure to help prevent further loss of vision from glaucoma.

What is tube shunt surgery?

Tube shunt surgery involves placing a small tube implant in the eye. This tube, less than 1mm in diameter, connects the front aqueous fluid chamber of the eye, where pressure usually builds up, to an area underneath the conjunctiva, or ‘superficial layer’ of the eye. Attached to this shunt is a plate which acts like a reservoir, allowing fluid to drain to a space above it.

One of the main advantages of the tube shunt is that it is more resilient to the healing process which can affect other types of glaucoma surgery such as trabeculectomy. The position of the tube and the reservoir tends to be underneath the eyelid, normally the upper eyelid, so it is not usually cosmetically apparent in most positions of eye gaze for somebody’s who’s had this operation.

Find out more

For more commonly asked questions about tube shunt surgery, including about types of tube shunts, what to expect after surgery, the purpose of the patch graft, possible complications, how effective tube shunt surgery is for lowering pressure and suitable candidates please click here for a downloadable PDF (for the full version).


Trabeculectomy is a traditional eye surgery approach to treating glaucoma. The procedure aims to lower the eye pressure to help prevent your glaucoma worsening and further loss of vision.

Why, and when, do I need trabeculectomy?

Because there are some risks associated with surgery, trabeculectomy is reserved for people who are at high risk of their glaucoma worsening and vision loss. Usually, this is after other glaucoma treatments, such as eye drop treatments and/or laser treatments, have not been successful. It may be needed after less invasive, but less effective glaucoma surgery (sometimes called minimally invasive glaucoma surgery – MIGS).

It may be recommended when there is very high eye pressure which cannot be controlled with less invasive treatments, and there is a very high risk of losing vision from glaucoma – even before substantial vision loss. There is also evidence that it can be a reasonable first line of treatment for people who already have severe glaucoma when they are first diagnosed.

Find out more about trabeculectomy

For more commonly asked questions about trabeculectomy, including about the procedure itself, the recovery after surgery, possible complications, chances of a successful surgery and suitable candidates please click here for a downloadable PDF (for the full version).

The American Academy of Ophthalmology Annual Meeting often showcases exciting new research that is of relevance to patients. In this year’s meeting, Professor Khawaja was particularly interested in a study presented on Selective Laser Trabeculoplasty (SLT), a common initial treatment for glaucoma and ocular hypertension, which has been shown to be almost as effective when introduced as a second-line of treatment after three years of eye drop therapy.

The research, conducted by Gus Gazzard, a fellow ophthalmologist at Moorfields, aligns with the results of a study Professor Khawaja published in 2019, entitled ‘Real-World Outcomes of Selective Laser Trabeculoplasty in the United Kingdom’. In this study, Professor Khawaja examined the outcomes of SLT for glaucoma patients across multiple eye units in the UK with the aim of identifying which factors can predict a good outcome. He found that SLT can be equally effective in patients already using eye drops, all other factors being equal.

Factors that make SLT an effective glaucoma treatment

A key consideration before SLT is the starting pressure. Professor Khawaja’s previous research highlighted the need for a high starting intraocular pressure for SLT treatment to work most effectively. The results showed that SLT was not as effective for those needing to lower pressure from an already low starting point. It is believed that this is because the laser only targets one part of the drainage system; there is a pressure level that the laser cannot get below due to resistance remaining in other parts of the drainage system.

Professor Anthony Khawaja attended the American Academy of Ophthalmology in San Francisco, where he attended the launch of a new glaucoma visual field device from Topcon healthcare, called TEMPO™. After a hands-on trial of the device, Professor Khawaja is delighted to share his positive experience, comparing it with the current standard in the UK, the Humphrey Field Analyser.

Testing field of vision in glaucoma

Tests for glaucoma fall in three broad categories – assessment of intraocular pressure, the optic nerve head assessment and field of vision. There have been many advances in the assessment of the optic nerve head (e.g. OCT scanning) and intraocular pressure (e.g. the Ocular Response Analyzer) over the last decade. Now, with advances in affordable and portable virtual reality (VR) technology, there have been recent advances in visual field testing too. TEMPO™, the new device that Professor Khawaja trialled, demonstrated a few key benefits over the standard Humphrey Perimeter:

Comfortable – using a snug binocular-style headset, which effectively blocked out even the bright lights of the convention centre
Quick – Both eyes checked simultaneously, reducing set-up time – taking 3 minutes in total for both eyes (less than half current testing time). Also, not having to cover one eye at a time made the test considerably more comfortable
Easy Assessment – Easy to analyse the results which are in a format that is very similar to the familiar Humphrey perimeter results

Benefits of VR devices for detection and monitoring of glaucoma

There are clear benefits with using VR technology for visual fields in terms of time saving and ease of testing – so the potential for more patient testing and more effective prevention of blindness due to glaucoma. The benefits may be in the community for glaucoma detection, and also in the clinic to help with monitoring.

There is also the potential for other similar VR devices to be used for testing in the home, making it easier to test the elderly or those with mobility issues. Professor Khawaja believes that it will not be long before these advancements in vision field testing will be available in the UK, improving the lives of patients with glaucoma. A major challenge will be how healthcare providers will make the switch from such an established device, and research needs to be in place to ensure any new device can perform equally well at glaucoma detection and monitoring.

A new glaucoma treatment has recently been launched by Santen, and so far it is showing promising results. Roclanda, is the first new treatment for glaucoma in the UK for 25 years. An exciting development in glaucoma care, this new treatment option could help save the sight of many thousands living with this serious eye condition.

Currently, Mr Anthony Khawaja sits on a global expert committee, advising pharmaceutical company Santen on best practices for the use of Roclanda. Here, he explains how it works, the benefits of the new drug, as well as the risks.

Roclanda – How it works

Roclanda is an eye drop that contains the combination of a Rho kinase inhibitor (Netarsudil) and the commonly used glaucoma drug, latanoprost. It works by increasing the outflow of aqueous fluid from the eyes in the conventional way (through the trabecular meshwork).

Usually, medications for glaucoma increase outflow through other areas of the eye (unconventional), or reduce the amount of fluid the eye produces. By opening up this conventional fluid outflow pathway, this treatment compliments the other commonly used treatments in glaucoma and therefore may have some particular benefits.

Roclanda – Key benefits

For patients already taking a number of other glaucoma medications, there is evidence that shows Roclanda can still have a strong effect.

The key benefits of the new treatment are:

  • Convenience – only once daily dosage required
  • Effective even when used in combination with other glaucoma treatments
  • Lowers pressure even when the starting pressure is low

Roclanda – Side effects

The risks associated with Roclanda are generally mild to moderate, which is why it is authorised for use in the EU. The main side-effect is conjunctival hyperaemia (red eye). However, this is not a serious side-effect, or vision threatening and can be easily resolved by ceasing the treatment.

Of course, for some patients, medications alone will not resolve their condition and they will require glaucoma surgery. However, there have also been a lot of recent innovations in glaucoma surgery. The PreserFlo Microshunt is a particularly effective and less invasive surgery option. Anthony is currently chairing a panel of European experts to report the best practices for this device.

Professor Anthony Khawaja recently attended the annual Swedish Ophthalmology Society conference in Uddevalla as an International expert guest speaker. Representing UCL Institute of Ophthalmology and Moorfields Eye Hospital in London, he presented on ‘Genetics and Personalised Medicine in Glaucoma’.

Focusing on the Swedish ‘Fika’ (coffee and sweet pastry) rituals and high caffeine consumption per capita (8.2kg per year), included in the presentation was a recent study that Professor Khawaja co-authored. The research looked at the link between habitual caffeine intake, with intraocular pressure (IOP) and glaucoma. The study, which involved over 120,000 British participants, concluded that for those with the strongest genetic predisposition to glaucoma, greater caffeine consumption was associated with higher IOP and higher risk of glaucoma.

Professor Khawaja pointed out that although this association was seen across the whole range of caffeine intake, those drinking over 5 cups of coffee (or other caffeinated drinks) per day were at the most significant risk. But, this study doesn’t prove conclusively the cause and effect and further randomised controlled trials would be needed to see if there are other factors involved.

There is building evidence that simple lifestyle changes can help to manage eye pressure, with limiting caffeine consumption being just one. “Glaucoma patients often ask if they can help to protect their sight through lifestyle changes, however this has been a relatively understudied area until now,” he said.

One of Professor Khawaja’s research group’s major interests is lifestyle factors that may influence glaucoma risk. They have examined multiple factors including alcohol consumption, salt intake and physical activity.

Mr Anthony Khawaja is President of the European Eye Epidemiology (E3) consortium, which promotes the sharing of knowledge and research between 31 groups originating from 13 different European countries.

They recently published their most recent research in the sector-leading Ophthalmology journal on the association of common systemic medications with glaucoma and intraocular pressure (IOP).

The study found that calcium channel blockers (CCBs) had a modest and statistically significant association with glaucoma.

Glaucoma and blood pressure drugs

Patients with a history of CCB treatment had a 23% higher likelihood of having glaucoma as compared with individuals who never used the antihypertensives. In contrast, beta-blocker therapy was associated with modestly reduced intraocular pressure (IOP), which is associated with a reduced risk of glaucoma.

“While our novel findings require further studies to determine whether the associations are causal, these findings will be of interest to physicians caring for glaucoma patients with systemic comorbidities,” Mr Anthony Khawaja explains.

“A potentially harmful association of CCBs for glaucoma is particularly noteworthy, as this is a commonly prescribed class of medication,” he added. “If further studies confirm a casual nature for this association, this may inform alternative treatment strategies for hypertensive patients with, or at risk of, glaucoma.”

Coverage of the study was widespread and Mr Anthony Khawaja was also delighted to be included in Bottom Line newsletter, the largest subscription newsletter in the US which offers expert advice on everything health related. They covered the study in their most editorial round-up.

This article was originally written by Mr Anthony Khawaja for The Ophthalmologist.

Although glaucoma can cause irreversible, irreparable damage to vision, treatment can slow or halt disease progression, so early detection is important. Unfortunately, our current screening tests – if applied to a general population – don’t work well enough; as a result, population screening for glaucoma is not currently recommended in some countries, including the UK and the US.

Using people’s genetic codes to identify a subset of the population that will benefit from screening may be the solution to this problem. In the last decade, there has been huge progress in discovering many of the genetic variants that contribute to glaucoma risk. It was back in 2018 when we first realized that the great number of risk variants we had discovered could be considered collectively to predict – with surprising accuracy – whether someone would end up developing glaucoma. This approach of combining thousands of risk variants into a single number, a polygenic risk score, has become popular across many common diseases, including glaucoma.

Instead of having to screen whole populations, genotyping enables targeted screening for those at a higher risk for glaucoma. Our current screening tests will perform much better when applied to a subset of the population with a higher prevalence of undetected glaucoma. In other words, there will be far fewer false positive referrals to secondary care if our current screening tests are applied to this enriched subset of the population.

A separate challenge in glaucoma care comes after diagnosis. At present, we cannot accurately predict which of our patients are at the highest risk of progressing and losing vision. If we could better predict this, we could ensure our limited healthcare resources are used optimally, focusing on the highest risk patients, but also saving costs, unnecessary treatment, and follow-up for those at lower risk.

It remains unclear whether the genetic variants which increase the risk of developing glaucoma also increase the risk of vision loss among patients with glaucoma. Instead of comparing people with glaucoma to people without glaucoma in the general population, we need more longitudinal genetic studies amongst cohorts of glaucoma patients, identifying the genetic variants that lead to worse disease.

This article was originally written for Ophthalmology Times by Caroline Richards.

Genotyping and artificial intelligence are together starting to predict the progression of glaucoma in individual patients, sparing them from suboptimal treatments and adverse effects. Recent research efforts are exploring modifiable risk factors such as caffeine consumption.

I have previously interviewed glaucoma specialist Anthony Khawaja, PhD, MA (Cantab), FRCOphth, on the therapeutic area of precision medicine, and I was interested in talking with him again to revisit the rapidly developing field and discuss the latest promising research. Here is our interview.

Why is there a need for precision management in glaucoma?

AK: Because the way we currently practice medicine is very much evidence based, which, as I will describe, has its shortcomings. We all know that the highest-quality evidence comes from randomized controlled trials. For example, the ocular hypertension treatment study [randomly assigned] people with ocular hypertension who did not have glaucoma to eye pressure lowering or no eye pressure lowering.2

Those whose eye pressure was lowered had a dramatically reduced chance of converting to glaucoma over the subsequent 5 years. This means that if we treat everybody with ocular hypertension, fewer people will convert to glaucoma.

However, around 90% of untreated people did not convert to glaucoma. Therefore, if we treated everybody with ocular hypertension, as [findings from] the randomized controlled trial might suggest is a good idea, then we would be treating many people unnecessarily: some would benefit but others would receive treatment they did not need. And, of course, some people will develop [adverse] effects to the treatment, and treatments have costs to the health care providers and to the patients, depending on the health care setting.

Another similar example is the United Kingdom Glaucoma Treatment Study (UKGTS), [whose data] showed that treatment with latanoprost can halve the chance of established open-angle glaucoma getting worse, compared with placebo.3 This, again, suggests that if all patients were the same—if everyone was average—then treating them would be a good idea.

But not everybody is the same and three-[fourths] of people in the placebo group in this study did not measurably progress over the 2-year study period. This suggests that some people who fulfil our diagnostic criteria for glaucoma might not actually need treatment.

On the flip side of that, 15% of the people who received latanoprost progressed, meaning that they perhaps needed a different treatment or a more intensive treatment strategy. The overall message here is that evidence-based medicine is great to tell us what is best to do on average, but not what is best for an individual patient.

There is a great picture of Barack Obama from when he was launching the Precision Medicine Initiative in 2015.4 He stood by a model of DNA, the double helix, since one of the key enablers for personalising our approach to managing patients lies in genetics and genomics: leveraging an individual patient’s genetic code to better understand how they will individually respond to different treatment strategies.

One reason that this is an exciting time for personalised or precision medicine is that measuring the genetic code has become so cheap: You can have it done at a local high street pharmacy in the UK for less than £150 [$174].

One genotyping study that is going to start in the UK soon, called the Our Future Health study,5 will measure common variations in the genetic code in 5 million adults at a cost of around £20 [$23] each. This 1 test can inform us about how best to manage people at risk of not only common blinding eye conditions but also cardiovascular disease, dementia, breast cancer, prostate cancer, and almost any medical condition you can think of. This demonstrates that we are at a very exciting point in time in precision medicine and I think we are going to see big changes within the next decade.

What specific benefits can precision medicine bring to glaucoma patients?

We usually assess a person’s personal risk according to how bad their glaucoma is when they first present, but we tend to have to monitor them for at least a couple of years before we can fully or better understand that risk.
Genetics will help us stratify our patients right from the outset, to better identify those who will be on a downward trajectory in 5 years’ time, so we can treat them better, and those who will have barely changed in 5 years—the really low-risk patients who we can spare [from] the costs and [adverse] effects of treatment, freeing up precious health care resources and giving the glaucoma specialist time to focus on patients who have a much higher risk of going blind.

Given the rapidly increasing number of [patients with] glaucoma and our limited health care resources, we need these kinds of innovations. This is not a hope but an absolute must. Secondly, we have so many different glaucoma treatments now: many classes of drops, different forms of laser, [and] different forms of surgery from very minimally invasive to highly effective but much more invasive and risky.

However, we are not very good at predicting who will respond well, and we tend to treat patients in a trial-and-error manner. It is rare that a patient comes to severe long-term harm from this—[adverse] effects are often temporary—but it does not provide patients with a great experience and is also a massive waste of resources.

There is growing evidence to suggest we can predict using genomics who will respond well to treatment such as selective laser trabeculoplasty. Work is…ongoing, so watch this space!

What research are you most excited about at present?

I am really excited about genetic data, not just from patients with glaucoma versus patients without glaucoma, but also from patients with established glaucoma, where we know what their treatment pathway has been, their response to treatments, and their vision loss trajectory. Once we have these large data sets, we can start to accurately validate prediction algorithms that incorporate genetics for clinically meaningful outcomes such as risk of progression, rate of progression, and response to different treatments.

Another exciting area is modifiable risk factors for glaucoma. Knowing which lifestyle factors influence glaucoma risk has been a challenge, as studies have tended to be small and results inconsistent. But now, with large studies such as the UK Biobank,6 we are better able to ask these questions.

We recently brought together a multidisciplinary collaboration of nutritionists, nutritional epidemiologists, statistical geneticists, ophthalmic epidemiologists, and glaucoma specialists from multiple institutions around the world, such as Harvard [University], Mount Sinai, the Pasteur Institute, and beyond.

The first thing we looked at was caffeine, partly because all the investigators enjoy consuming caffeine. We were interested to know whether it influences the pressure in the eye and the chances of having glaucoma.

A high genetic risk of glaucoma is in some ways a proxy for how well developed the aqueous fluid outflow channels are: If they are not adequately developed, such that they are starting to fail at an older age, then the outflow channels cannot handle the additional aqueous that is produced as a result of consuming more caffeine. This pushes up the pressure and increases the chance of developing glaucoma.

Interestingly, we found that there does not seem to be a strong association in the population overall, other than when you focus on people at high genetic risk of glaucoma. So only in the high-risk people, who can be determined with inexpensive genotyping tests, [is] high caffeine intake associated with a higher eye pressure and a greater chance of having glaucoma.

What does this mean for patients? Currently, if a patient’s glaucoma is well controlled, I certainly would not advise them to stop consuming caffeine or reduce their caffeine intake. But if a patient is getting worse despite best medical or surgical treatment, then I think they need to know this information. I would say that, although it is not proved, if you do consume a lot of caffeine, you may wish to consider reducing or stopping, given what we know.

It may work, it may not work; but certainly if I was a patient and I was getting worse despite all best efforts, this is the type of information I would like to know. In the future, I think we will be giving people lifestyle advice according to their genotype.

Where does artificial intelligence (AI) fit in?

We have used AI to look at retinal photographs of patients in the UK Biobank. Doing this, we processed around 80,000 photographs in less than a day, assessing whether there are features of glaucoma and measuring the vertical cup disc ratio. This is something which would take a decade for human graders to undertake.

Genetic data are available for everyone in the UK Biobank, so this allowed us to carry out the largest genome-wide association study for vertical cup disc ratio,7 identifying many new genetic markers for glaucoma. These genetic markers were very predictive for glaucoma prevalence in the independent EPIC-Norfolk study [European Prospective Investigation Into Cancer in Norfolk Prospective Study; NCT03424668].8

The other thing with AI is that it will complement genetic prediction models. Currently, using all our clinical skills, OCT [optical coherence tomography] scans, and visual fields, we can only phenotype a patient so far. There are extra clues in their genetic markers that will tell us about that patient’s profile, their prognosis, their susceptibility to disease, and their response to different treatments.

There are also hidden signatures that humans cannot currently interpret, while AI can. So I think that AI assessment of imaging in particular is going to give us some extra clues that can further help personalize the care of our patients.

Where will we be 10 years from now?

I think we will have started pilot programs in which health care users meeting quite broad criteria are genotyped, which will inform personalized care strategies. For glaucoma, it might be a personalized screening strategy.

For example, patients with the top 10% risk of glaucoma might be advised to start having annual eye checks at the age of 40, whereas the bottom 10% will not have any specific eye tests and will just go to the optometrist opportunistically. People who are somewhere in the middle might start at the age of 50 and be screened every 2 years.

In 10 years, the best management is going to be an intersection of genomic prediction models and AI models.

This article was originally written for Optometry Today.

Study finds high coffee intake increases odds of developing glaucoma among patients with genetic predisposition towards elevated eye pressure

Researchers have published new findings connecting coffee intake to glaucoma among patients with a family history of elevated intraocular pressure (IOP).

The study, which was published in Ophthalmology, involved analysing UK Biobank records of 120,000 people collected between 2006 and 2010.

Scientists examined the relationship between IOP, caffeine intake and self-reported glaucoma diagnosis. They also assigned each participant an IOP genetic risk score.

Coffee and glaucoma risk

Overall, high caffeine intake was not associated with a risk of developing elevated IOP or glaucoma.

However, among people with a genetic predisposition towards high IOP, greater caffeine consumption was linked to a higher IOP and higher glaucoma prevalence.

Those in the highest genetic risk category had a 3.9 times greater chance of developing glaucoma if they consumed three cups of coffee a day, compared with those in the lowest genetic risk group who drank no caffeine.

Co-author Anthony Khawaja, from University College London and Moorfields Eye Hospital, shared that the study illustrated those with a high genetic risk of glaucoma may benefit from moderating their caffeine intake.

“It should be noted that the link between caffeine and glaucoma risk was only seen with a large amount of caffeine and in those with the highest genetic risk,” he said.