Why Do Patients With Normal Eye Pressure Go Blind From Glaucoma?

Through this project, we aim to understand why patients with normal pressure in their eyes still go blind; could there be a mechanical explanation, such as the presence of abnormal forces. AIM1. We will assess the robustness of the optic nerve head (the site of damage in glaucoma) in patients with low-pressure glaucoma and in patients with high-pressure glaucoma. We may find ‘undiscovered’ mechanical features of the eye (e.g. oddly shaped or deforming ocular structures) in those two groups that may explain the development of the disease in either group. These mechanical features will be discovered using AI & engineering tools. AIM2. We will assess whether the features discovered in AIM1 will help predict who will go blind and how fast.

Glaucoma is a major blinding disorder and is defined by cell damage at the back of the eye within a structure called the optic nerve head (ONH). When cells are damaged, visual information cannot reach the brain, and the patient is declared legally blind from glaucoma. At the beginning of the last century, we thought that glaucoma would only occur when the pressure within the eye was elevated. Mechanically it makes sense: a high pressure would stretch tissues and cells within the eye which could result in damage. While this has already been accepted as a common mechanism for glaucoma, some patients with normal pressure within their eyes still develop glaucoma. To understand this, our group, and others, have identified other loads acting on the ONH, such as the pressure within the skull that can be transmitted back to the eye, and the pulling force of the optic nerve – the cable linking the eye to the brain – that can increase during eye movements. It may be that some patients develop glaucoma because those 2 loads are abnormal independently of eye pressure. Our research is exciting because we will propose engineering and artificial intelligence tools to fully assess and understand the robustness of the ONH in a given patient. Our goal is to establish whether ONH robustness can help us predict who is at risk of developing future glaucoma damage, and if proven, we will be able to provide earlier treatment in the eyes that are deemed mechanically unstable.

Our research is exciting because we will propose engineering and artificial intelligence tools to fully assess and understand the robustness of the optic nerve head (ONH: the main site of damage in glaucoma) in a given patient. Our goal is to establish whether ONH robustness can help us predict who is at risk of developing future glaucoma damage, and if proven, we will be able to provide earlier treatment in the eyes that are deemed mechanically unstable.

Once our study is complete, the general public may benefit from an improved understanding of the physics of the eye. In other words, the general public may understand that certain eye shapes (or changes in eye shape with eye pressure or other forces) may predispose an individual to a certain type of glaucoma. The general public may understand the importance of being screened for glaucoma after reaching a certain age.

For our research field, a better understanding of the physics of the eye, will inevitably open the door to new glaucoma treatments that are in high clinical need.