Exploring changes in the early stages of AMD

Dr Ashley Wood, Cardiff University -£98,163

This research used new imaging technology to investigate how and why vision and the eye change in the early stages of age-related macular degeneration (AMD). The team aimed to improve our understanding of these early changes and explore new ways to detect and monitor AMD before noticeable sight loss occurs.

What was the problem?

It can be difficult for people to notice the initial changes caused by early and intermediate AMD. As a result, AMD is often diagnosed only after noticeable sight loss has occurred. Detecting changes earlier could lead to better monitoring and treatment, helping people retain more of their vision and potentially supporting the development of new treatments to prevent early AMD from progressing.

One of the first changes people may notice is difficulty adjusting to changes in light. This is called dark adaptation. The team at Cardiff University developed a new test to detect changes in dark adaptation called High Fidelity Imaging Retinal Densitometry (IRD).

The test measures levels of visual pigments found in the light-sensitive photoreceptor cells in the retina – rods and cones. These pigments absorb light and begin the process that allows us to see. Understanding how these pigments change with age and in conditions such as AMD can provide valuable insights into the processes that contribute to vision loss.

What did the project achieve?

The project aimed to better understand how visual pigments and blood flow beneath the retina change with age and in eyes affected by AMD.

The team used two advanced imaging techniques: High Fidelity Imaging Retinal Densitometry (IRD) and Optical Coherence Tomography Angiography (OCTA). IRD measures the amount of visual pigment in the eye and how quickly it recovers after exposure to light, while OCTA provides detailed images of the blood vessels beneath the retina.

The team found that people with early AMD had a measurable deterioration in visual pigment recovery after exposure to light. The new IRD test was able to measure this consistently and reliably.

The researchers also established a baseline for how visual pigments change with age in healthy eyes, providing an important reference point for future research into conditions such as AMD. They produced the first visual pigment ‘maps’ showing how visual pigment density and recovery after light exposure are affected in eyes with early and intermediate AMD.

OCTA also showed decreased blood flow beneath the retina both with increasing age and in early-stage AMD.

What's next?

This research has paved the way for future studies and potential clinical applications that could improve how AMD is diagnosed and monitored. Further research could help us better understand the changes that happen in the early stages of AMD and support the development of new approaches to treatment, ultimately helping people preserve their vision and quality of life.