Grimoldby School presented a cheque for £164 to Lindsey Blind Society in 1998.
The money was raised by staff and pupils who were sponsored to take part in the recent Louth Fun Run.
They were also joined by some of their parents. John Keily, treasurer of the Lindsey Blind Society, received the cheque from staff members Jo Sangiar, Adam Sanders and pupils.
In all, 13 children, two staff and five parents took part.