In all moderately dim light in which people without the disorder can read large print, people with the disorder cannot read such print.

In an otherwise darkened concert hall, these people will see a dimly illuminated red exit sign more clearly than small dim white lights that mark the aisles.

These people typically see more acutely at night and in dim light than do most people who do not have the disorder.

Eyeglasses that are transparent to red components of light but filter out other components of light help these people see in moderately bright light.

These people perceive colors other than red in the same way as do most people who do not have the disorder.