The analysis of refractive error in the group of 10000 children and teenagers the age of 6-15 based on examinations in two Polish major regions - Szaflik, Jerzy; Prost, Marcin; Zaleska-Żmijewska, Anna; Hapunik, Adam; Wójcik, Anna (Klinika Oczna / Acta Ophthalmologica Polonica Supplement, 2004)