I'm Vas Sadda, Professor of Ophthalmology at UCLA and the Doheny Eye Institute, and I'm here at AAO 2026 in New Orleans, and I had the opportunity to present at the Retina Subspecialty Day on the topic of different methods of assessing the progression of atrophy.

It's obviously, assessing the progression of geographic atrophy is quite important in this era of therapeutics for GA. And I've highlighted how there are many nuances to this and how the method you use can really impact the conclusion you might reach.

I've reviewed methods like just measuring the GA area, or applying a square root transformation, or a perimeter adjusted GA. And I highlighted that all of those methods, while they are improvements, there are still important limitations, in particular because they don't factor in the location of the atrophy. And we know that atrophy can progress more slowly towards the foveal center.

So, I introduced the concept of using something we call the front advancement, or basically the progression of the lesion border. And the advantage of that method is that you can actually adjust it based on the location. And we know, again, the GA lesions grow more slowly towards the fovea. We showed that, in part, it's because of a greater photoreceptor density. So the kill rate of photoreceptor stays constant.

But again, that may be a preferred method for following and tracking the progression of these patients, which I think is really critical, because we'll want to make sure we can differentiate natural slowing of the atrophy compared to slowing of the disease from treatment, in this era of GA therapeutics.