New research from Germany has shown, for the first time, that certain early changes in patients with age-related macular degeneration (AMD) can lead to a measurable local loss of vision.

The discovery could help to improve the treatment and monitoring of this eye disease, and to test new therapies.

A research team from the University Hospital Bonn (UKB) Eye Clinic, in cooperation with the University of Bonn and in close collaboration with basic and clinical scientists, has specifically examined patients with early forms of AMD. The researchers focussed on the so-called iRORA lesions, which are very early anatomical signs of retinal damage.

“We used the microperimetry method to precisely measure the visual acuity at these affected areas of the retina,” explained the researchers.

This involves measuring the sensitivity of the retina to light stimuli to identify visual impairments. As the affected retinal areas are smaller than 250 micrometres, routine clinical devices reach their limits.

A high-resolution research instrument developed in Bonn, known as an adaptive optics scanning light ophthalmoscope (AOSLO), helped out.

“It enabled imaging of the retina with microscopic resolution and allows functional testing of small areas down to individual photoreceptors,” said Dr Wolf Harmening, from UKB Eye Hospital and the University of Bonn.1

The results were clear: the visual acuity in the areas of the lesions was markedly reduced. With the standard method, the loss was on average seven units compared to a control region. With the precise AOSLO method, the loss was 20, which corresponds to a reduction in light sensitivity by a factor of 100.

This early retinal damage could serve as a marker to better monitor the progression of the disease and treat it at an early stage.

“Our investigations show that even these early lesions can contribute to a very localised but nonetheless significant deterioration in vision in our patients," explained Dr Harmening.

“This makes them a potential marker that can help to better monitor the progression of AMD and treat it at an earlier stage,” said Professor Frank Holz, Director of the UKB Eye Clinic.

The study was published in BMJ Open Ophthalmology.2

References available at mivision.com.au