Perichiasmal tumors: diagnostic and prognostic features.

Area of Science:

• Neuro-ophthalmology
• Neurology
• Oncology

Background:

• Intracranial tumors can compress critical visual pathways, including the optic nerve, optic chiasm, and optic tract.
• Such compression frequently leads to significant visual impairment, necessitating a thorough understanding of associated visual field defects.

Purpose of the Study:

• To analyze the clinical presentation and visual outcomes in patients with tumors compressing the intracranial visual pathways.
• To characterize the patterns of visual field defects and pupillary responses in this patient cohort.

Main Methods:

• Retrospective review of 49 patients with tumors compressing the intracranial optic nerve, optic chiasm, or optic tract.
• Analysis of presenting symptoms, visual acuity, pupillary examination findings (relative afferent pupillary defect - RAPD), and visual field testing results.

Main Results:

• The majority of patients presented with visual loss predominantly affecting one eye.
• Seventy-seven percent had a relative afferent pupillary defect (RAPD), and 96% exhibited a hemianopic defect; all patients had at least one of these findings.
• Junctional visual field defects (39%) were nearly as common as bitemporal defects (46%), with hemianopic defects often obscuring nerve fiber bundle defects.
• Poor preoperative acuity correlated with poorer postoperative acuity, though 95% achieved 20/40 or better in at least one eye postoperatively.

Conclusions:

• Compression of intracranial visual pathways by tumors characteristically causes unilateral visual loss and specific visual field or pupillary defects.
• While visual field patterns can be complex, surgical outcomes are often favorable, with most patients retaining functional vision.