[Functional assessment before and after interventions on the optic chiasm system].
OBJECTIVES: In the course of a tumor in the area of the optic chiasm the optochiasmal system is often exposed to compressive and vascular irritations. This study deals with the functional results (visual acuity and visual field) before and after surgery based on the primary situation and morphology of the tumor in order to give a prognosis on this matter. METHODS: 62 patients (41 female, 21 male) suffering from tumors in the area of the optic chiasm were retrospectively reviewed. The duration of the follow-up was an average of 25.82 months, +/- 20.04. Among the tumors investigated there were 36 pituitary adenomas, 20 meningiomas, 4 craniopharyngiomas, one histiozytosis X and one gangliozytoma. For visual field examination the Humphrey Field Analyzer, program 30-2, was used. 34 tumors (54.8%) were excised by the transsphenoidal approach, 28 patients (45.2%) underwent transcranial surgery. RESULTS: As for visual acuity, of the 124 eyes 53 eyes (42.8%) improved after surgery, 64 eyes (51.6%) remained unchanged, 7 eyes (5.6%) deteriorated. Of the patients who underwent transsphenoidal surgery, 28 eyes (41.2%) improved after operation, 36 eyes (52.9%) remained unchanged, and 4 eyes (5.9%) worsened. In case of transcranial surgery, 25 eyes (44.6%) improved, 28 eyes (50.0%) remained unchanged, whereas 3 eyes (5.4%) worsened. There was a postoperative improvement in 53.2% of the visual fields, 37.1% remained unchanged, whereas 9.7% deteriorated. CONCLUSION: Both the transsphenoidal and transcranial approaches showed excellent visual outcome. Our experience indicates an excellent prognosis for improvement of visual acuity and visual fields provided an adequate procedure. Results depend, however, on the primary functional and morphological situation. In the case of a large supra-/parasellar tumor component a postoperative deterioration of vision may occur.