"What a curious feeling! I must be shutting up like a telescope."

ALICE-IN-WONDERLAND-Syndrome
named after the novel by Lewis Carroll.
A disorienting neurological condition affecting human perception,
first described in 1955 by English psychiatrist John Todd (1914-1987).
Aso known as Lilliputian hallucination and Todd's syndrome.
Sufferers experience distortions of space, time and body image, visual
hallucinations, micropsia or macropsia. The entire body or parts of it
are experienced as altered in shape and size.
A temporary condition, it is often associated with migraines, brain
tumours, and the use of psychoactive drugs.
A description of the syndrome as experienced by a 31 y.o. Brit in a Guardian article.