[Early symptoms and findings in optic nerve meningiomas]

While evaluating radiotherapy results in patients with primary and secondary optic nerve sheath meningiomas (ONSM) treated between 1993 and 2002, a large amount of data about early signs and symptoms has been collected which might be helpful for establishing an early diagnosis.

We have reviewed the charts of the patients available at the Centre of Ophthalmology, collecting especially pretreatment data.

112 patients, 4 with bilateral tumours, 83 % female were included. Mean age was 51.7 years. Visual acuity loss with relative afferent pupillary defect was the main symptom and sign in primary ONSM (38 patients). Median interval between first symptoms and diagnosis was 12 months. Optic discs were in approximately one half atrophic, the other half were swollen, and only rarely normal (3 cases only). Retinociliary shunt vessels were seen in 10 cases. Nerve fibre bundle defects were the major visual field finding (including constriction and central scotoma). Visual acuity was better than 0.5 (20 / 40) in 46 % and worse than 0.1 (20 / 200) in 30 %. In secondary ONSM, the interval to diagnosis was with a median of 6 months shorter than in primary ONSM. Approximately half of the optic discs were atrophic, only 6 % were swollen. Even here nerve fibre bundle defects were dominating, only 7 % had vertical hemianopic defect. Visual acuity was better than 0.5 (20 / 40) in 30 % and in worse than 0.1 (20 / 200) 22 %. 45 % had ocular motility disorders.

Vertical hemianopic defects were surprisingly rare. The high rate of nerve fibre bundle defects and the relatively high number of patients with good visual acuity might explain why this disorder is occasionally mistaken for glaucoma. A typical clinical appearance can be outlined: mainly mid-aged women, slowly progressing visual loss, frequently motility disorders, relative afferent pupillary defect, nerve fibre bundle defects and atrophic or--mainly in primary ONSM--swollen optic disc form the characteristic picture.