[Analysis of the changes in the causes of blindness and significant vision loss among children and young adults born between 1974 and 2004].

Introduction: Visual impairment develops serious medical, psychological, social and economical problems. Thus, of most importance is improvement in prophylaxis, early diagnosis and treatment. THE AIM of this paper is to define the reasons of blindness and significant loss of vision in children and youths in Poland, and changes in them among children and youths under the age of 24, born between 1974-2004, with classification by age.

Subject And Method: Included in the study were the records of 2,518 children and youths under the age of 24, associates of the Polski Zwiazek Niewidomych (PZN, Polish Association of the Blind); these were analyzed for the prevalence of each cause of vision loss. There were two groups. The first group were files of 1,504 students and pupils in the institutions for blind and visually impaired children, and the archives of PZN, describing the members who joined it between year 1974 and 1998. The second, comparative group, was based on files of 1,014 children and students, who joined PZN between year 1999 and 2004. Each group was also analysed within different age groups.

Results: The most important causes of visual impairment are: optic nerve atrophy, retinopathy of prematurity (ROP), high myopia, congenital cataract and retinal degradations. Changes in them between 1998-2004 introduce a percentage growth of optic nerve atrophy from 21.66% to 25.41% and decrement in vision degrading stages of ROP from 14.14% to 10.71%, in development disorders from 8.09% to 7.10%. There is an alarming growth in congenital toxoplasmosis percentage, from 1.06% to 2.39%, and of congenital cataract, from 3.02% to 4.47%. High myopia among the visually impaired remains at the same level. There is a big growth in the percentage of heavy (bilateral) injuries, which cause significant vision loss. Less often, the cause of serious vision damage are uveitis, secondary glaucoma and toxocariasis.

Conclusions: The study conducted between 1998-2004 revealed changes in the causes of blindness and significantly vision loss in children and youths under the age of 24, as compared to a similar study conducted between 1974-1998. There is constant increase of the optic nerve atrophy as a cause of vision loss, and decrease among vision impairments caused by vision damaging stages of ROP. Cataract and congenital abnormalities are more frequent among youngest children. Cortical blindness, formerly rarely diagnosed, is becoming a significant factor. The results of our study, describing the changes in blindness and significant vision loss factors, should provide a proper rationale for developing a strategy for control of visual impairment in children and youths.