Dr. Ted Maddess discusses the FDA-cleared ObjectiveFIELD Analyzer, a device that has been clinically researched in Australia for more than 12 years. The 2024 AAO Annual Meeting served as the US launch and rollout of the product, which is where Dr. Maddess gave Ophthalmology 360 an in-depth overview of its capabilities.
Question:
Can you tell us about the objectiveFIELD Analyzer and its capabilities?
Dr. Ted Maddess:
It just measures how well your retina functions, the person actually sitting being tested. Then if you look at the operator view, you can actually see these gigantic eyes and little copies of the stimuli. If you want, you can actually look inside, but you sort of see the same thing on the side here.
You can see the little stimuli here, that’s what he’s seeing. Here you can see the pupil being tracked in real time. Monitoring the blue line is showing the diameter change.
Question:
This is probably AI usage?
Dr. Ted Maddess:
Nope. No. No AI. We could probably use them in future, but no AI involved.
This is for the left eye, and the right eye. This is showing sensitivity change. The darker tones being slightly less sensitive than normal. Blue means a little more sensitive. When you switch this, these are all in milliseconds, so about 500 milliseconds, about half a second until the pupil reaches its maximum response to one of those flashes, so many, many flashes. Each region is tested in this test about 35 times, and you take the average, but these numbers are how quick the response was and how big the response was.
Because it’s a relative size, we don’t need to worry about things like sometimes people’s pupil is a bit misshapen, not perfectly circular. That’s okay because we’re fitting a circle to whatever their shape is. Then we measure the relative change. Small pupils, weird-looking pupils, it doesn’t matter too much.
On standard automated perimeter, people fail to test about 10% or 15% of the time. The number of people whose pupil problems are so bad that their problem for this is much, much smaller.
Question:
How is the technology unique?
Dr. Ted Maddess:
It’s the first truly objective perimeter that uses cortically driven responses of the pupils. There’s no button to press. Instead, it measures retinal function directly and both eyes are measured at the same time and patients seem to like that. The standard wide field test generates 4 30-2 reports in about 7 minutes for both eyes. Those reports immediately show you something quite unique about the device. In addition to sensitivity, we also measure response delay at every single region in the field. Of the 4 test reports that are generated from one run, 2 are for the left and right sensitivities, and 2 are for the left and right delays. The delays provide new information that might improve your confidence in knowing about visual field damage and also changing your treatment decisions.
There are also 3 other protocols, other than the one that I mentioned, that assess both eyes in under 90 seconds for both eyes. They achieved that by doing a slightly coarser sampling of the visual field. There are 2 wide field versions and a macular version. The macular version is very interesting because its stimuli actually match the ETDRS grid regions that you’ll find on every OCT there is.
That means that comparing structure and function is incredibly easy and those rapid tests have demonstrated high diagnostic and prognostic power in early to late stage AMD, diabetic eye disease, and some neurological diseases.
One thing we’ve noticed after following some patients for between 3 and 10 years in different diseases, we’re starting to understand that the sensitivities and the delays can progress differently. That seems to be telling us about different aspects of these diseases. That’s a completely new and interesting thing.
Another thing the OFA does is it monitors hypersensitivity, which is completely ignored by standard automated perimetry. That can be very informative. For example, peripheral macular hypersensitivity can tell you which AMD subjects will respond well to anti-VEGF therapy, and even whether or not therapy is required.
OFA can also detect diabetic eye damage before any classical retinopathy, and perhaps that indicates who you should treat with things like fenofibrate. Interestingly, the response delays are more informative in diabetes.
Question:
What should clinicians know about this device?
Dr. Ted Maddess:
Our key thing is that the test duration is completely predictable. Time restrictions mean that often in the clinic we have to resort to using a lower coverage 24-2 test. But objectiveFIELD is providing 30-2 reports in less time. There’s a macular version of that, a bit like the 10-2 tests.
Reports are presented in a classic style that you’ll easily recognize all the features of. Another really important point is that conventional threshold testing for measuring the sensitivity of the retina is really just a proxy for sensitivity measurement. Whereas OFA measures the sensitivity directly from the cortically driven pupil responses.
By taking the human cognitive element out of the equation, reproducibility gets better, which improves ability to monitor change over time. There are now 35 publications on the objectiveFIELD. They’re all available on the Konan Medical website. They’re mostly about glaucoma, AMD, and diabetic eye disease. But there’s a bunch of papers on neurological diseases and also on the cortical basis for the instrument.
Learn more at konanmedical.com.
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