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Isolated relative afferent pupillary defect secondary to contralateral midbrain compression
Cheun Ju Chen1, Mia Scheufele, Maushmi Sheth
1Departments of Neurology and Ophthalmology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA.
Archives of Neurology
|September 15, 2004
Summary
A rare case of left relative afferent pupillary defect was found in a patient with a pineal tumor. This finding highlights that pupillary defects can occur contralateral to postchiasmal pathway lesions.
Area of Science:
- Neuro-ophthalmology
- Neuroanatomy
- Medical imaging
Background:
- Relative afferent pupillary defects (RAPD) typically indicate ipsilateral anterior visual pathway lesions.
- Understanding the pupillary light reflex pathway is crucial for diagnosing visual disturbances.
Observation:
- A patient presented with headache and an isolated left relative afferent pupillary defect.
- No other neurological deficits were identified during the initial workup.
Findings:
- Brain MRI revealed a pineal tumor compressing the right rostral midbrain.
- The study reviews the neuroanatomy of the pupillary light reflex, noting the nasotemporal bias of decussating fibers.
Implications:
- This case demonstrates that relative afferent pupillary defects can arise from contralateral postchiasmal pathway lesions.
- Such findings necessitate a thorough neuroimaging evaluation to identify the underlying cause, even in the absence of other neurological signs.