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30 April 2021

Effectiveness of two treatments for the most common cause of sight loss to be compared

The TIGER trial will compare the effectiveness of two treatments for age-related macular degeneration with the hope of improving outcomes for those living with the condition.

Ophthalmologists inspecting an eye through a microscope

Age-related macular degeneration is the most common cause of permanent and severe sight loss in the UK – 1.2 million people have the condition in its early stages and 700,000 people UK-wide have late-stage age-related macular degeneration.

Timothy Jackson, Professor of Retinal Research at King’s College London, will be leading a team of researchers to test a novel treatment to clear sight-threatening blood clots that a small percentage of people with wet age-related macular degeneration experience. This surgical intervention will be compared to the standard existing treatment.

Wet age-related macular degeneration occurs when the light sensing cells inside the back of the eye are damaged. It is usually treated with repeated injections of drugs known as anti-VEGF into the back of the eye. These drugs aim to reduce the abnormal new blood vessels that cause the disease.

However, in a small proportion of people with wet age-related macular degeneration, the fragile new vessels bleed into the eye, causing a large haemorrhage. Blood is toxic to the light-sensing cells so that when the blood finally clears, it leaves behind permanent scarring and severe sight loss.

This clinical trial, known as the TIGER study, involves a surgery that uses an existing ‘clot-busting’ drug that is injected into the clot to dissolve it. Then, a bubble of gas is injected into the eye. The bubble of gas floats inside the clear body fluid that fills the eyeball. After surgery, the patient must position their head face forward for five days, so that the bubble of gas floats onto the back of the eye. This pushes the dissolved blood away from the most sensitive part of the eye. Patients who have the surgery will still need to have regular anti-VEGF injections to control the underlying disease.

Many eye surgeons consider that surgery has the potential to improve vision compared to injections, but surgery carries downsides including the risk of complications. We do not know the net effect of these contrasting risks and benefits, which is why we need a trial to compare surgery plus injections to injections alone. Our aim is to find out if surgery is more likely to improve vision than standard care with anti-VEGF injections alone. If the surgery is proven effective, it can be made available to more people and surgeons can use it with greater certainty.

Professor Timothy Jackson

The trial will involve 210 participants recruited from a number of European centres, with half receiving surgery and anti-VEGF injections, and half receiving anti- VEGF injections only.

The project is funded by leading research charity Fight for Sight, with the support of EURETINA. More information on the clinical trial is available from Fight for Sight. 

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Professor of Retinal Research and Consultant Ophthalmic Surgeon