In the past decade, several significant advancements have been made in the arena of glaucoma diagnosis. Spectral domain optical coherence tomography (SD-OCT), newer algorithms in trend analysis of visual field studies, and combined visually evoked potential (VEP) and pattern electroretinography (ERG) studies have been the hallmarks of such recent advancements.
I delivered two lectures recently at a conference in Halifax, Nova Scotia, which highlighted recent novel devices and concepts in glaucoma diagnosis and treatment.
The first course was on diagnostic advancements, and it included a review of where we are with SD-OCT studies, VEP/ERG analysis, and visual field analysis and progression algorithms. I also covered conceptual considerations, such as low cerebral spinal fluid pressure and its potential link to glaucoma.
Previously from Dr. Casella: Helping patients better understand glaucoma
The second course, which went through potentially promising therapeutic approaches on the horizon, left the audience with one cold hard fact: With all that we can do on the diagnostic side of glaucoma, there has yet to be a therapeutic approach to date which should come before lowering intraocular pressure (IOP). ODs need to look for signs earlier and treat glaucoma early on in an effort to preserve ganglion cell vitality and its corresponding visual function.
Someday, the future of glaucoma therapeutics will likely deliver a novel neuroprotective approach that will be proven effective in preserving ganglion cells. However, it is always important to treat glaucoma earlier in the hopes of preserving visual function.1 ODs are left with the task of detecting glaucoma earlier or—perhaps more conceptually—determining which patients will get glaucoma.
A small but potentially significant study was recently published. The authors purported to have accurately and safely identified apoptotic neurons in the retinas of glaucoma patients.2 The investigators labelled a molecule known as annexin A5 with a fluorescent dye and injected it into patients intravenously in combination with detecting of apoptosing retinal cells (DARC)—an imaging technique.
The DARC count is defined as the number of apoptosing retinal neurons. This metric was found to be higher in patients with progressing glaucoma.2
Whether patients have sick or healthy neurons, apoptosis (programmed cell death) occurs in all people It is commonly accepted that apoptosis accelerates early on in glaucoma (and other neurodegenerative diseases, for that matter).3
This early sign of the disease has been elusive to in vivo assessment in humans. If this novel imaging technique proves to be effective (more and larger studies are needed), then it could become possible to identify and stage glaucoma in its earliest form.