The girl was taken to Royal Sussex County Hospital in Brighton after the incident, at 9.30pm, which happened on the ‘Rocker’ ride.
Police initially said the girl had suffered injuries to her ankle and wrist but have this afternoon said she had bruising to her eye.
The Health and Safety Executive will investigate today.
A police spokesman said: “Police were called to Marine Parade at 9.30pm to a report of a medical incident.
“A teenager had fallen from one of the rides and was taken to Royal Sussex County Hospital in Brighton.”