A young woman having an eye test.

Last year we relaunched our innovation and improvement grants to benefit patients and staff of Moorfields. We are excited to fund Dr Colin Chu’s project to test whether advanced DNA sequencing could help identify undetected causes of uveitis.

Moorfields Eye Charity’s innovation and improvement grants aim to support testing and developing new ideas, which will optimise clinical practice, service provision and positively impact Moorfields patient and staff experience. 

In this innovation and improvement project, Dr Colin Chu will collaborate with Great Ormond Street Hospital (GOSH) to develop a new clinical test to diagnose rare causes of uveitis. 

The challenge

Uveitis, an umbrella term for ocular inflammation, is a rare condition but accounts for nearly 15% of registered blindness and a large degree of comorbidities, hospital visits and medical costs. 

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2-5 in 10,000

people in the UK are affected by uveitis each year

Early diagnosis of uveitis is very important and most cases recover well with appropriate treatment. If left untreated, uveitis can lead to further complications such as glaucoma, cataract and vision loss. 

What is uveitis?

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Uveitis refers to inflammation of the middle layer of the eye, which is called the uvea.

The uvea is made up of the iris (the coloured part of the eye), the ciliary body (a ring of muscle behind the iris), and the choroid (a vascular layer of tissue that supports the retina).

Uveitis usually causes a red, painful eye with cloudy vision. These symptoms may vary in intensity from mild to severe. The type of uveitis may be categorised according to which part of the eye is affected.

Anterior uveitis: Refers to inflammation of the iris (iritis) or inflammation of the iris and the ciliary body (iridocyclitis). It is the most common type of uveitis, accounting for 75% of cases in adults.

Intermediate uveitis: This affects the area behind the ciliary body and the retina. It tends to occur in children, teenagers and young adults.

Posterior uveitis: This is a severe form of uveitis which affects the back of the eye i.e. the choroid and the retina, and can seriously affect vision. 

Panuveitis is a type of uveitis that affects the entire uveal tract i.e. inflammation of both the front and the back of the eye at the same time. This form of uveitis can be sight threatening.

Uveitis can also be acute, lasting for a few weeks; or chronic, lasting for more than three months, and recurring symptoms that can vary over time. 

What causes uveitis?

  • idiopathic (unknown cause)
  • associated with underlying systemic autoimmune disease
  • infection

For many patients with complex uveitis, the cause is never identified. This impedes treatment options and patients’ outcomes.

Infectious uveitis

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Examples of pathogens that can cause uveitis include:

- viruses: herpes simplex virus HSV, cytomegalovirus CMV, varicella zoster virus VZV - chickenpox, rubella

- bacteria: tuberculosis, syphilis, lyme, bartonella

- parasites: toxoplasma

- fungi: Candida and mould species like Aspergillus

There is a large number of other pathogens that are rare and frequently not tested for, mainly because the volumes of clinical samples are too small for extensive testing and the routine tests rely on knowing exactly what pathogens are being sought.

Even if an active infection or infectious trigger is suspected, current diagnostic tests are limited and frequently unable to identify the cause.

Finding a solution

In collaboration with GOSH, Dr Chu and team plan to establish and validate a new clinical pathway to test for infections in patients with complex and chronic uveitis. 

1 in 3

patients with uveitis have suspected infection in the eye

A sample of ocular fluid from the front of the eye will be taken in Moorfields clinic and sent for expert testing by Dr Julianne Brown and her team at the GOSH Clinical Metagenomics Facility. 

The GOSH team established this technology to test for difficult-to-diagnose infections, such as brain infections. The charity’s funding will now allow for a collaborative project to optimise and deploy metagenomic tests to diagnose causes of uveitis.

Dr Colin Chu

Metagenomics is a new sequencing technology capable of detecting all genetic material found in a single patient’s sample. 

This genetic material is like a molecular signature that can be compared with large international libraries of genetic material from almost all known organisms to identify rare pathogens.

This way metagenomics is capable of identifying almost every known infection in a patient’s sample, including all known bacteria, viruses, parasites and fungi. 

This finding could transform patient care.

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    Patient story

    Metagenomic sequencing was performed in a patient with a five-year history of complex uveitis that did not respond even to high doses of medication. The patient had been suffering with severe pain and visual loss long-term. Standard tests did not detect an infection. Metagenomic analysis however identified a type of bacteria, which is an exceptionally rare cause of uveitis. After targeted antibiotics the patient has made a remarkable recovery.

This patient story provides early evidence that the metagenomic testing can work to identify causes of uveitis with positive impact on patients. 

The potential

This project aims to establish a new diagnostic service for patients with complex uveitis of unknown cause, assisting with diagnosis and identifying new opportunities for treatment. 

Moorfields is a leading specialist eye referral centre, so early implementation of new technologies that we can clinically validate is critical to improved local and national patient care.

Dr Colin Chu

Applying metagenomics could aid the discovery of unexpected or new causative agents of uveitis or avoid missing others that are not routinely tested for in current NHS services. 

It could reduce missed diagnoses, increase our understanding of uveitis and establish a first-in-the UK service at Moorfields.

Patient stories

We’re funding groundbreaking research that could transform lives affected by uveitis.

Project Details

Funding scheme

Innovation and improvement

Grant holder

Dr Colin Chu

Area(s) of work

Uveitis

Award level

£100,000

Start date

January 2025

Grant reference

IAI-24-104