Improving diagnosis of glaucoma
UNSW scientists have bridged a key knowledge gap in the diagnosis of glaucoma, allowing observable damage to the optic nerve caused by the condition to be accurately and directly linked to vision loss.
Glaucoma is one of the leading causes of irreversible blindness in the world, with more than 300,000 Australians estimated to have the condition.
Sometimes referred to as the “sneak thief of sight”, it is often asymptomatic in the early stages of the disease, with about half of all cases in the general population estimated to remain undiagnosed. Glaucoma leads to irreversible damage of the optic nerve, resulting in the loss of vision.
Clinically, glaucoma is diagnosed through a combination of clinical tests including eye pressure measurement; visual inspection of eye structures, specifically around the optic nerve; and assessment of functional loss using a technique referred to as Standard Automated Perimetry, which measures a person’s field of vision.
Recently, new imaging instruments that allow precise measurements of the optic nerve thickness and integrity have been increasingly used for diagnosis.
For decades, clinicians and scientists have been baffled by a mismatch between structural and functional deficits noticing that, in some cases, there was no detectable loss of vision despite obvious damage to the optic nerve.
This is in contrary to theoretical work suggesting eye structure and eye function should change at the same time.
This mismatch potentially prevents accurate and timely diagnosis of glaucoma and creates a high risk of irreversible vision loss for patients not being treated in time.
Now, for the first time, researchers have established a model that can robustly predict changes in ganglion cells - the neurons making up the optic nerve – that occur with age or with the disease and correlated them with functional loss.
The Centre for Eye Health is a joint initiative of UNSW Sydney and Guide Dogs NSW/ACT.
The study, led by Dr Barbara Zangerl, is published in the journal Investigative Ophthalmology and Visual Science, one of the top-ranking journals in the field.
Reference: “Consistency of Structure-Function Correlation Between Spatially Scaled Visual Field Stimuli and In Vivo OCT Ganglion Cell Counts”; April 2018, Nayuta Yoshioka; Barbara Zangerl; Jack Phu; Agnes Y. J. Choi; Sieu K. Khuu; Katherine Masselos; Michael P. Hennessy; Michael Kalloniatis; Journal: Investigative Ophthalmology and Visual Science, http://iovs.arvojournals.org/article.aspx?articleid=2677964
1 May 2018.