Visual parameters of Polish special schools students

The purpose of this study was to coduct a visual screening of students in special schools with a set of tests chosen by the faculty and staff of the Department of Optometry and Visual System Biology of Poznań University of Medical Sciences. Students mentally handicapped (N = 318) between the age of 7 and 22 (mean age 14.4 ± 2.84) were screened. Group 1 were children aged 7 to 12 (n = 65), group 2 were subjects aged 13 to 16 (n = 167) and group 3 included people aged between 17 and 22 (n = 86). The scope of the screening included: auto-refractometer (Shin-Nippon A type) without cycloplegia, visual acuity for distance, positive lens test +1.00 D (diopter), spatial vision (stereo) at near, color vision and near point of convergence. 72 children (22.6%) were prescribed correction, but only 30 children actually wore glasses on a permanent basis (9.4%). Of those not using correction (n = 288): in group 1 the adopted criteria for visual acuity for the right eye were not met by the 38% of the respondents or 35% for the left eye; group 2 – 36% of the respondents failed (right eye) and 31% (left eye); 50% of students in group 3 did not meet the visual acuity criterion. Stereo was failed in groups 1 and 3 by almost 60% while in group 2 the test was failed by 47% of the respondents. The results of the refraction revealed a small degree of myopia in each eye of 38% in the entire sample. Hyperopia was found in 42% (right eye) of the students whereas 44% (left eye) in the entire sample. Astigmatism ranging from 0.75 to 2.00 D was noted in the case of 32% of people. This study indicates the need for a systematic vision screening, more than just visual acuity at distance, among the students in special schools.