Purpose: To evaluate the distribution in Denmark of histologically verified optic nerve lesions according to histological diagnosis, gender and age during a period of 60 years and to calculate frequency and possible changes in frequency during the observation period.
Methods: All optic nerve lesions reported at the Eye Pathology Institute, University of Copenhagen, during the period 1940-99 were investigated. All similar lesions reported at all pathological departments in Denmark during 1974-99 were also investigated.
Results: The number of optic nerve lesions identified totalled 313 in 298 patients. The frequency of histopathological optic nerve lesions was seen to have increased significantly over the last 25 years, and at present, an average of 12 lesions per year are recorded. Lesions in children represented 42% (130). The percentage of lesions suffered by children remained constant throughout the observation period. Benign tumours constituted 33% (44) of the total number of tumours in adults and 61% (62) in children. Frequencies of glioma and optic nerve sheath meningioma increased significantly during the last 25 years. Subjects presenting with optic nerve sheath meningioma exhibited a significant difference in age at presentation: the mean age of women at presentation was seen to be 48.8 years, while the mean age of men at presentation was seen to be 29.7 years. The most frequent lesion seen in children was glioma and in adults invasion from malignant uveal melanoma.
Conclusion: Histologically diagnosed optic nerve lesions are rare and consist primarily of tumours. The increase in frequency of optic nerve lesions in Denmark during the last 25 years is due to an increase in the number of benign tumours.