In some neurological disorders, the pupil does not react to light, but it does react to accommodation. This is called “light-near dissociation”.
In Adie syndrome, damage involving the ciliary ganglion manifests light-near dissociation and a tonically dilated pupil (usually unilateral).
Other causes of light-near dissociation involve damage to the brainstem, where a tonic pupil is not produced. Brainstem causes of light-near dissociation include Argyll Robertson pupil and Parinaud syndrome.
Irene Loewenfeld is generally credited for being the first physiologist to make this distinction.