Posterior uveitis is a rare eye disease that can damage the retina and the optic nerve, which may result in permanent blindness. It can affect a person of any age, even children, and may lead to the loss of vision in one or both eyes.

Posterior uveitis is more likely to happen to people who have specific genes. Also, people with weak immune systems are more prone to this rare eye disease.

At the University of Bonn, researchers investigated color-coded fundus autofluorescence as a supportive diagnostic method for treating posterior uveitis. The type of uveitis can be determined by the retina’s fluorescence which is a necessary prerequisite for an appropriate diagnosis of the disease.

Scientific reports now contain the results of the research.

Blurred vision, floaters, and unusual light perception – those affected by the rare disease posterior uveitis feel no pain. “But the consequences can be severe: About five to ten per cent of blindness worldwide is caused by uveitis. Uveitis is a rare disease, but posterior uveitis in particular, has a poor prognosis and often requires immunosuppressive therapy”, explains Dr Maximilian Wintergerst of the Ophthalmology Department at the University of Bonn.

The disease has different forms; the retina or choroid in the eye gets inflamed in posterior uveitis. The incident light in the retina gets converted into nerve impulses, and the outer layer is supplied with nutrients from the choroid.

Different Therapy management

“It’s not easy to distinguish between the numerous subtypes of uveitis,” says Wintergerst. All the subtypes of uveitis require a different therapeutic, making reliable diagnosis important.

Due to this, researchers of the ophthalmology department at the University of Bonn, with the colleagues from Medical Biometry and Rheumatology departments and the university hospital of ophthalmology in Switzerland, investigated a new image technique that can help in the treatment of posterior uveitis.

The team of researchers assessed the Color-coded fundus autofluorescence (Spectrally Resolved Autofluorescence Imaging). An Italian company centerVue iCare provided the researchers with recently developed devices for examinations.

In the process, the retina is illuminated with bluish light. The retina re-emits the light at a different wavelength after absorbing it. “The green-to-red ratio of the light emitted from each inflammatory focus depends, among other factors, on the exact posterior uveitis subtype involved”, explains Wintergerst.

In the research, 45 participants eyes were examined. The appropriate subtype of uveitis was already diagnosed in all of them. This included their ophthalmologists’ findings, radiologic findings, laboratory investigations and sometimes genetic and interdisciplinary clinical studies.

Reliable diagnosis with the help of color-coded fundus autofluorescence. The green-red ratio in fundal fluorescence of the eye for approximately 800 foci of inflammation in the patient’s eyes is assessed by researchers.

Our results indicate this ratio can be very characteristic and helpful as a marker for differentiating the various posterior uveitis subtypes, states Prof. Dr Robert Finger, co-author of the study and head of the uveitis clinic at the Ophthalmology Department at the University Hospital Bonn. “It could allow us to make more confident diagnoses in the future”.

The purpose is to document the disease’s long-term progression and to develop treatment recommendations. In the current study, we present the precise technical background of color- coded fundus autofluorescence in ophthalmology in collaboration with our international partners,” says the head of the department Prof. Dr Frank Holz.
“This technology may also allow better monitoring of posterior uveitis in the future, in addition to more reliable diagnoses.”
This study is published in science daily.