Predicting glaucoma risk using genetics
14 January 2020
Glaucoma affects millions of people across the world each year. We’re funding research looking into the genetics behind glaucoma.
Moorfields Eye Charity is excited to report on a breakthrough study on glaucoma which has been published in the prestigious journal Nature Genetics, and co-authored by Moorfields consultant eye surgeon Anthony Khawaja.
The study aimed to better understand the development of glaucoma - its symptoms and the risks associated with it.
What is glaucoma?
Glaucoma is an eye condition where damage to the optic nerve causes sight loss. It is usually caused by the pressure inside your eye rising too high.
Your eye is full of fluid, which helps it to keep its shape and function properly. If too much fluid builds up inside the eye, the pressure rises and squeezes the optic nerve at the back of the eye.
This can cause damage to your optic nerve - a bundle of over a million nerve fibres that carry signals between your eye and your brain.
Pressure might build up in the eye when:
- fluid is stopped from draining away
- extra fluid is produced after an eye injury or infection - this is called ‘secondary glaucoma’
- there is an abnormality in the shape of the eye in children - this is called ‘congenital glaucoma’
Glaucoma tends to develop slowly over many years. As there is currently no cure for glaucoma, treatment focuses on early diagnosis, careful monitoring and regular treatment to help prevent further sight loss.
9 in 10
people diagnosed with glaucoma today who get the treatment they need will retain useful sight for the rest of their lives
It is not currently possible to repair the optic nerve once it has been damaged, so any vision lost to glaucoma cannot be recovered. If left untreated, glaucoma can lead to blindness.
There are usually no symptoms of a rising pressure in the eye until sight loss occurs, so regular eye tests are the best way to help spot the condition early.
The study - a leap forward in understanding
Led by scientists from King’s College London, University College London, Massachusetts Eye and Ear and Harvard Medical School, researchers studied 140,000 people with glaucoma drawn from the UK Biobank and EPIC-Norfolk.
They took eye pressure readings from each patient and compared them with their DNA to assess how likely it was that they would develop the condition.
By comparing the pressure test results with a genetic analysis of the many common, small variations in DNA that contribute a tiny amount to overall eye pressure, the team was able to identify 133 genetic variants in the DNA of those who had high pressure readings, and so were at highest risk of developing the condition.
The genetic variations were able to predict whether someone might develop glaucoma with 75 per cent accuracy
Glaucoma affects 480,000 in England and millions worldwide
This research could pave the way for a genetic based screening program to help identify the world’s leading cause of incurable blindness.
The results of the study represent a major advance in the fight to tackle the degenerative condition, which has virtually no symptoms in the early stages.
Speaking about this publication, Dr Khawaja (consultant eye surgeon at Moorfields Eye Hospital and researcher associated with the NIHR Biomedical Research Centre at Moorfields and UCL Institute of Ophthalmology), said:
We are now more able to predict the risk of an individual developing glaucoma. By understanding how glaucoma develops we can get ahead of the curve and support both those living with the disease and those who may develop it.
Speaking with Moorfields Eye Charity, Dr Khawaja discussed his own research programmes and the potential research avenues the results of this paper could stimulate.
He said there are some really interesting avenues he would like to pursue, including looking into the potential for personalised medicine and stratifying patients to enhance their treatment and outcome experiences.
Further research opportunities include:
- increasing prediction accuracy
- using genetic variants for targeted screening - this could help identify people at risk of glaucoma early and before their sight is irreversibly affected
- understanding the molecular basis of the genetic variants that may cause glaucoma
- seeing if response to treatment type can be indicated by the genetic variants - this could shed light on why some patients respond to certain treatments while others do not.