Amblyopia affects binocular vision, research suggests

Fatema Ghasia, MD, director of the Ocular Motility Laboratory at the Cole Eye Institute, sat down with Ophthalmology Times® executive editor David Hutton to discuss her presentation at the 2022 ARVO meeting held in Denver, CO. Her talk, entitled, "Fixation eye movement abnormalities, stereopsis and interocular suppression in amblyopia," shed light on how amblyopia may affect binocular vision.

Video transcript

Thank you for having me. So the talk was on looking at fixation eye movement abnormalities and how it affects binocular visual functions and amblyopia.

Since we know amblyopia is lazy eye, it affects about 5% of children. And previously, amblyopia was primarily thought to be a problem where vision in one eye is weaker than the other. But recent research has suggested that it has implications on your binocular vision, so the talk was on looking at how fixation eye movement abnormalities differ in patients who have good binocular visual functions versus those who don't.

So in this experiment, what we have done is we specifically measured suppression. So amblyopia is now increasingly thought to be a problem with the suppression of images from the weaker eye. And so there are newer treatments that are coming out that aim to reverse this interocular suppression. And so what we basically found is that if you had certain eye movement abnormalities, and by that I mean, certain forms of nystagmus that are seen, then you're more likely to have poor binocular visual function, as well as possibly can have more interocular suppression.

What can this mean for patients?

You know, now, the fact that we realize that, you know, the suppression plays a major role in in amblyopia — so, there are newer anti suppressive amblyopia, treatments — and so if we know of the eye movement abnormalities they have, if you knew ahead of time, it may give us insights into prognosis of the condition and, and also perhaps give us insights into response to treatment.

So, you know, if you had certain fixation, eye movement abnormalities and you have worse, then there is a likelihood that after treatment, your recovery or binocular visual functions may not, you know, be complete in the sense that you can still have improvement in your visual acuity, but your binocular visual functions may not recover completely. I think it would help us understand response to treatment and give us some ideas about the prognosis.

What's the next steps for this research?

So the next steps would be to continue to, of course, you know, we would like to create a database of amblyopia patients, and kind of understand how fixation eye movement abnormalities can help us better gauge the pattern of visual function deficits that we see.

Amblyopia affects, you know, not just the visual acuity of one eye; it also has effects on contrast, sensitivity, it has effects on your depth perception, we now increasingly recognize the role of interocular suppressions, and we also know that it not only affects the lazy — or the weaker — eye, but it also has effects on the so-called good eye.

What we're trying to ultimately do is do a battery of tests on these patients before treatment, and then kind of follow them as they're doing the more conventional treatments of patching and eyedrops, versus the newer treatments that have recently been implemented, which are dichoptic treatments, which are anti-suppression treatments, and kind of see how fixation eye movements can help us figure out the pattern of visual function deficits that we see because we know that not all patients have all of the problems that I just described.

And so it will kind of help as this missing link between understanding the pattern of visual function deficits, as well as, to kind of see how the visual functions improve with that conventional and newer treatments.

Note: This transcript has been lightly edited for clarity.