Glaucoma has been called the ‘silent thief of sight,’ and as March 11-18 is World Glaucoma week, it seems timely to discuss recent insights in the diagnosis and treatment of a disease that is the world’s leading cause of irreversible blindness. Traditionally, glaucoma has been attributed to an increase pressure in the eye which ultimately damages the optic nerve, leading to vision loss. However, up to 20% of patients develop this disease with normal eye pressure, creating a challenge for both early diagnosis and effective treatment. Leading research is now looking at the disease as a relationship between the pressure not only in the eye but BEHIND the eye, known as our intracranial pressure (see photo).
Glaucoma would occur when the pressure inside the eye is higher than the intracranial pressure behind the eye. This means that it is the pressure difference at the optic nerve that causes the ‘pinching’ of the nerve fibres as they exit the eye, eventually leading to their destruction and associated vision loss. Studies have also shown that our intracranial pressure decreases after the age of 65 which would explain the increased risk of developing glaucoma as we age. This new insight of glaucoma as a 2-pressure disease is spurring the development of devices that can non-invasively measure the intracranial pressure behind the eye. As a result, we will be able to more effectively diagnose patients with normal eye pressures who are at greater risk of developing glaucoma. Conversely, for patients with high intraocular pressures, we will be able to determine if their optic nerve is truly at risk or if there already exists a healthy balance between the two pressures, thus avoiding unnecessary treatment.
When taking into consideration this new way to ‘look’ at glaucoma, there are also new treatment options currently available and on the horizon. In the surgical field, stents can be implanted into the eye to improve the outflow of fluid, lowering the eye pressure and is typically done in conjunction with cataract surgery. Under development are various devices and formulations to provide a more sustained delivery of glaucoma medication directly to the eye. The goal is to provide consistent medication that will control pressure for days if not months without daily maintenance. In eye care, a paradigm shift in how to more effectively diagnose and treat glaucoma is occurring now and…in the future of vision.