Information, screening and approval

Before the clinical trial can start, you meet with the study team to make sure the trial is suitable.

At this screening visit, the study doctor and study coordinator explain the trial, answer your questions and give you written information, including a consent form.

Some questions you might have include how long the trial will take, any risks and benefits, and what happens if you want to stop. You can read other common questions here.

If you decide to go ahead, you and the study doctor sign the consent form.

You then undergo an eye test and assessment to confirm you are eligible for the study. (Because clinical trials aim to find out if new treatments work, they need to recruit participants with specific health profiles. This means that not all patients are suitable for a particular trial. If this is the case, the doctor will discuss this with you.)

For the eye test, the study doctor examines your eyes with a special microscope that gives a magnified view of the front and back of the eye.

If you are eligible for this particular study, you are then booked in for your first treatment. In some cases this can take place on the same day.

Your study team includes a study doctor, who is an ophthalmologist, a study coordinator, who is an orthoptist and specialist nurses.

Starting the study

At your second appointment, known as a ‘baseline’ visit, you are assigned to a particular treatment group and begin treatment.

In a clinical trial, we usually compare two or more treatment options. When there’s no current therapy, we compare the new treatment to a placebo, or ‘pretend’ treatment.

You and your study doctor don’t choose which treatment you receive. And your study team is not necessarily aware of which treatment group you are in. This is common in clinical trials to avoid bias. It is called ‘masking’.

Discussion, support and testing

At each appointment, our study coordinator meets with you first to explain what to expect.

You will also be given our contact details so you can get in touch at any time.

The study coordinator carries out many of the assessments that are part of the study.

These include measuring your vision and eye pressure, recording your medications and medical history, and performing scans and photographs of your eyes.

We measure which lenses give you the best vision, and you are asked to read the letters on the chart.

We also ask you about your medical history and current medications, including vitamins and over the counter medications. We also measure your blood pressure, and sometimes your height, weight and temperature.

We use many different devices and techniques to obtain images of your eyes. One of the most common is optical coherence tomography, or OCT.

This test uses near infrared light to measure the thickness of structures of the eye. It can pick up changes in the retina, the layer at the back of the eye, which can be affected in eye diseases such as macular degeneration.

The test is safe and painless, and takes only a few minutes.

Some studies require fluorescein angiography, known as the ‘dye test’, which helps us see the blood vessels in the retina at the back of the eye.

In this test, a small amount of a fluorescent dye is injected into a vein in your arm. At the same time, we begin taking a series of photographs of the back of your eye that show the dye reaching the retina and other eye structures.

Photographs are taken for five to ten minutes.

Fluorescein angiograms can only be performed once or twice a year. Before you have the test, your study doctor will discuss the risks associated with this test.

Many of our clinical trials involve injections into the eye, as this delivers the medication where it is needed.

This ‘intravitreal’ injection is routine for many eye diseases including age-related macular degeneration, diabetic macular oedema and retinal vein occlusions.

The study doctor performs the treatment in a dedicated treatment room, assisted by an orthoptist or nurse. If the study is ‘masked’, the doctor and assistant are different to the team who perform your other assessments.

The doctor first applies local anaesthetic to your eye to make it numb. The eye and surrounding skin are then cleaned carefully with an antiseptic solution. The eyelid is held open with a special instrument, and the injection given into the jelly-like substance behind the white of the eye. The eye is then rinsed. The whole procedure takes about 10-15 minutes.

Some people describe the injection as feeling like ‘pressure’ on the eye, and others say they can feel a brief pricking sensation. You may experience grittiness in the eye for about 24 hours. Most people say eye injections don’t hurt and that they soon get used to them.

There is an extremely small risk of infection associated with eye injections.

Sometimes the injection can cause a small blood vessel to bleed on the white of the eye. This can look unpleasant for a few days but it is not dangerous.

From time to time throughout the study, we take blood and urine samples to check your health and see how you are responding to the medication.

We process samples at our dedicated onsite laboratory. The samples then go to a central laboratory for analysis.

Before you leave the clinic the study coordinator books your next appointment. In some trials, we provide you with a complete schedule of appointments.

While the amount of time at the clinic varies between studies, most visits take between two and three hours. Although we might do more tests than a standard clinic appointment, waiting times between tests is usually less.

Patient participation in clinical trials varies from several months, to years. You will know the expected duration of the trial before you start.