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COVID-19 Update

In response to COVID-19, the study team are working from home. We are continuing to keep in touch with the participants in the study. It may be that we are in touch with you by a different method than usual (for example we may telephone you to complete questionnaires, rather than send them by post). If you have any questions about the study please get in touch: email

You can also find information about COVID-19 from the NHS websites in England, Scotland, Wales and Northern Ireland There is also information about COVID-19 on the UK government website

Treatment of Advanced Glaucoma Study (TAGS): A multicentre randomised controlled trial comparing primary medical treatment with primary trabeculectomy for people with newly diagnosed advanced glaucoma 

What is the problem?

Glaucoma is estimated to affect around 2% of the UK population over the age of 40 years. This percentage increases with age so as many as 10% of people in their 80’s are affected. In England in the NHS there are over 1 million glaucoma-related visits per year. 

What is Glaucoma?

Glaucoma is a group of conditions which are characterised by the type of damage that affects the optic nerve at the back of the eye.  These conditions are often associated with an increase in the pressure within the eye (intraocular pressure). The optic nerve damage can result in loss of vision that gets worse without treatment.  The loss of vision is permanent but with early treatment it can be minimised.  Unfortunately, most patients with glaucoma are not aware that their vision has been affected.  This is because the loss of vision that occurs in glaucoma only affects vision for reading and recognising people when glaucoma has advanced to a late stage.  Treatment for advanced glaucoma aims to stabilise the pressure in the eye to prevent any further loss of vision.

For more information please look at the International Glaucoma Association’s website.

How is advanced glaucoma treated at the moment?

Currently there are two different ways to treat patients who have advanced glaucoma:

  • One way is to start to use eye drops.
  • The other way is to use surgery.

Both of these treatments are used successfully in the NHS.

Why does a study need to be done?

Both eye drops and surgery are used successfully but what we do not know is which treatment is better for patients’ quality of life or which is most successful over the long term in preserving patients' eyesight.

We will compare these two treatments (eye drops and surgery).  As both treatments are already being used the study is not testing out anything new or untested.  So participants who agree to take part will not receive any treatments that are not currently used successfully every day in the NHS.


What will happen in this study?

The study is designed to find out which treatment for advanced glaucoma patients prefer in terms of their quality of life. So we will ask patients who agree to take part to answer questions about:

  • what they think about their treatment,
  • what their experiences of the treatments are,
  • and how their vision is after treatment. 

The answers we receive to these questions are the most important information in this study. 

To get the answers to these questions we will send questionnaires to patients who participate five times over two years.

We will also ask patients who participate to come into the eye clinic four times to have their eyes checked and to ask them more about their experiences.

Patients who agree to take part in the study will have the treatment they receive randomly chosen.  As we are comparing the two successfully used treatments currently used in the NHS this means there is a 50:50 chance of being treated with eye drops or treated with surgery. The 50:50 chance of receiving each treatment is called random allocation. Random allocation means that each individual has the same chance of receiving each treatment and it is used to avoid bias.

Patients who agree to participate will always receive the care that is appropriate to their health.  This means that if the study allocated someone to be treated with eye drops but later the consultant thought that surgery would be necessary, then that patient would be offered surgery. 

You can read more about what we are doing in TAGS in this free to access academic paper.


Where will the study happen?

The study is running in 27 sites across England, Scotland and Northern Ireland. We recruited 453 participants in total across all sites in green in the map below (Nottingham, Norwich, Moorfields, St Thomas', Imperial College (Western Eye hospital), Portsmouth, Sunderland, Warrington, Heart of England (Birmingham), Dunfermline (NHS Fife), Cheltenham, Edinburgh, Hinchingbrooke, Bristol, Birmingham and Midland Eye Centre, Derby, James Paget, Manchester, Belfast, Maidstone, NHS Lanarkshire (Hairmyres, Wishaw, Monklands), Harrogate and York [and Scarborough], Dundee, Glasgow, Coventry and Sheffield.  


Is it safe to take part in the study? 

Yes.  Both treatments that the study is comparing are being successfully used in the NHS at the moment. 

The study has also been reviewed by the Medicine Health and Regulation Authority (MHRA) and they have stated that this is a comparison of two accepted standard treatment options currently being used in the NHS.

The study has been reviewed by an ethics committee who have approved the study.

The National Institute for Health Research at the Department of Health have agreed to fund this study because they believe it is very important to know which of these treatments is most successful in preserving patients’ quality of life.


Last updated: 13th September 2018


TAGS is coordinated by the Centre for Healthcare Randomised Trials (CHaRT) based in the Health Services Research Unit at the University of Aberdeen.

This study is sponsored by Nottingham University Hospitals NHS Trust.


General Data Protection Regulations (GDPR):

Nottingham University Hospitals NHS Trust is the sponsor for this study based in the United Kingdom. We will be using information from you and your medical records in order to undertake this study and will act as the data controller for this study. This means that we are responsible for looking after your information and using it properly. Nottingham University Hospitals NHS Trust will keep identifiable information about you for 15 years after the study has finished.

Your rights to access, change or move your information are limited, as we need to manage your information in specific ways in order for the research to be reliable and accurate. If you withdraw from the study, we will keep the information about you that we have already obtained. To safeguard your rights, we will use the minimum personally-identifiable information possible.

You can find out more about how we use your information at and/or by contacting Nottingham University Hospitals NHS Trust Data Protection Officer, Rory King, at