The impact and structural correlates of glare in albinism and infantile nystagmus

Brief plain language background

People with albinism have a reduced amount of melanin pigment, or no melanin at all, in their cells. In the iris of the eye, this lack of pigment causes numerous problems with vision, including nystagmus - involuntary, repetitive movements of the eyes. Infantile nystagmus (IN) means that the condition has been present since birth.

People with albinism and/or IN are severely impacted by glare – a sensitivity to light that makes everyday visual tasks such as reading difficult and uncomfortable.

What problem/knowledge gap does it help address

Studies into how glare impacts the ability to read have been limited because it is difficult to reliably measure the severity of abnormalities in the iris and accurately quantify glare in people with IN.

Although there are some methods for reducing glare, such as tinted glasses, it is difficult to assess their effectiveness with currently available eye tests.

Aim of the project

In this project, a PhD student will develop a reliable method to measure the impact of glare in people with IN. They will then use these measurements to study how effective tools such as tinted glasses are for improving reading.

This award will also contribute to building capacity in nystagmus research as it will lead to a PhD for an early career researcher.

Key procedures/objectives

The project will compare four groups of people:

• People with albinism who have IN and reduced pigment in their iris
• People with IN but no reduced pigment in their iris
• People who have IN but who experience glare because of defects in photoreceptors (cells that transmit light signals to the brain)
• People without albinism or IN

The student will:

• Develop a new type of scan (optical coherence tomography, or OCT) as a more accurate method for examining the iris in people with albinism.
• Assess the impact of glare on reading and other everyday visual tasks in people with IN and compare this to individuals without IN or albinism.
• Determine how the severity of iris abnormalities is linked to the effects of glare, so that reliable measurements of iris structure could be used to predict the likely impact of glare on tasks such as reading. This is especially important in children where it is difficult to measure reading performance directly.
• Explore whether tools to reduce glare such as tinted glasses/contact lenses and reading overlays improve reading performance.

Potential impact on people with sight loss

At the moment it is difficult for healthcare professionals to understand the extent of visual impairment people with albinism and/or IN experience because of glare. It is also difficult to know the best way to use tools such as tinted glasses to make these tasks easier. This study will develop an objective way to measure the impact of glare and provide evidence of the effectiveness of practical treatments.

The impact of this research will also extend beyond people with albinism and IN to anyone who experiences visual discomfort or reduced reading performance because of glare.