Glaucoma: The ‘silent thief of sight’
Updated: Oct 4, 2022
Stealthily, silently; generally, without pain or warning, the condition which is known as one of the leading causes of irreversible sight loss creeps up on most sufferers. Peripheral vision is often lost first, so it can be some time before this ‘silent thief of sight’ is picked up, and by then the damage which has already occurred is irreversible.
And yet, whilst glaucoma is one of the leading causes of sight loss, it is also a condition that can generally be managed once diagnosed.
Treatments can help to slow deterioration or even prevent further loss of vision. That’s why it is so important to have a regular eye test. The sooner that glaucoma has been identified, the sooner that treatment can begin.
So, what is glaucoma?
Glaucoma is a name given to a few conditions that are known as ‘optic neuropathies’. Basically, it is characterised by the death of particular retinal cells, often noticed as damaged to the optic nerve. Ultimately, the main causes appear to be down to increased pressure in the eyes, problems with blood supply to the retina and optic nerve and even potentially as a response to inflammation.
In the past, glaucoma was considered primarily as being caused by high pressure in the eye (IOP – intra ocular pressure). However, due to the improvement in detection techniques, such as OCT (Optical Coherence Tomography), we now know that half of all glaucoma patients have normal pressure.
The American Academy of Ophthalmology therefore adds a description saying ‘where the intra ocular pressure is too high for the continued health of the eye’.
It turns out that some people have normal pressure and glaucoma, known as Normal Tension Glaucoma. There are also people with high pressure in the eyes, without any glaucoma, known as OHT (Ocular Hypertension).
Typically, that high pressure may be due to a failure of the channels which drain the circulating aqueous fluid from the eye, or from an over production of the aqueous. This could be due to the channels becoming blocked over time (open angle glaucoma) or from an injury to the eye, or from the Iris pushing forward to close the drainage channels (closed angle glaucoma).
And whilst glaucoma is known as the silent thief of sight, one version – acute angle closure glaucoma – does bring noticeable symptoms such as headaches, eye pain and even nausea and vomiting. That’s because this type of glaucoma happens suddenly. If these symptoms occur, the best advice is to get your eyes checked out immediately.
Ongoing research into glaucoma is looking to identify not only the causes of glaucoma but also whether there is any way of reversing the condition. We know that age plays its part, but so does ethnicity and family history. One paper commented that:
A person’s risk of developing open-angle glaucoma is about 10 times higher if a parent or sibling has it.” 
This has led researchers to examine possible genetic factors which could lead to new treatments in the future. For example, one early-stage study by the Harvard Medical School has completed a proof-of-concept study showing that
“it’s possible to reverse both age-related vision loss and eye damage similar to that caused by glaucoma, in mice, using epigenetic reprogramming.”
The research is still in its very early stages and it does appear that successful reprogramming may depend on how recent the damage is. In the meantime, the best way to guard against glaucoma stealing your sight away is to undergo regular eye examinations and start treatments as soon as a problem has been identified.
Occuity is working on the PM1, the world's only non-contact, handheld pachymeter, to allow both clinicians and technicians to take a corneal centre thickness (CCT) measurement quickly and easily. These CCT measurements help to improve the accuracy and reliability of IOP (intra ocular pressure) measurements.
The PM1 will support the earlier, faster, and more accurate screening of glaucoma, allowing patients to prevent vision loss through timely diagnosis and appropriate treatment.