Glaucoma often affects peripheral vision first, and central vision loss occurs late in the disease, making early detection difficult as individuals may not notice gradual peripheral vision decline.

“the other big problem with glaucoma is that it affects our peripheral vision first and only very late in the disease does it pinch in and finally pinch off the center of our vision in typical glaucomas and that's a real problem because we don't notice if our peripheral vision is down you know our peripheral vision isn't that good to begin with and if you're driving and you can see a pedestrian step off the sidewalk you think your peripheral vision is fine but actually your per peripheral vision could already start being damaged by glaucoma and you won't notice it in regular daily life”