Bitemporal Hemianopsia in a Case of Tilted Optic Nerves

Tilted optic nerves are known to cause visual field defects, most commonly a superotemporal defect, however bitemporal hemianopia in the absence of a compressive chiasmal lesion is uncommon (1-3). We report a case of tilted optic nerves as the cause of bitemporal hemianopia in a patient with neuro-ophthalmologic symptoms of blurred vision and headache.

177 Bitemporal hemianopsia in a case of tilted optic nerves Rikki Cunningham 1, Yin Allison Liu 2 1 University of California, Davis School of Medicine, 2 University of California, Davis Introduction: Tilted optic nerves are known to cause visual field defects, most commonly a superotemporal defect, however bitemporal hemianopia in the absence of a compressive chiasmal lesion is uncommon (1-3). We report a case of tilted optic nerves as the cause of bitemporal hemianopia in a patient with neuro-ophthalmologic symptoms of blurred vision and headache. Description of Cases: A 43-year-old female with essential hypertension presented to the neuro-ophthalmology clinic with new onset blurred vision. Ophthalmic history included high myopia corrected with bilateral laser-assisted-in-situ-keratomileusis (LASIK) 13 years prior to presentation. She endorsed increasingly frequent headaches for six months but otherwise denied diplopia, transient visual obscurations, photopsia, photophobia, and retrobulbar pain. Ophthalmic examination revealed normal best corrected visual acuity and normal visual fields to confrontation, however perimetry testing using Humphrey Visual Field 24-2 demonstrated bitemporal defects with densely enlarged blind spots of both eyes. Optical coherence tomography (OCT) demonstrated normal retinal nerve fiber layer and ganglion cell complex thickness. Funduscopic examination demonstrated tilted optic nerves bilaterally with normal disc margins. Neurologic examination was normal. Magnetic resonance imaging with gadolinium using pituitary protocol showed no mass or mass effect onto the optic chiasm and no signs of increased intracranial pressure. The patient’s vision remained normal and repeat perimetry nine months later demonstrated the same pattern. Conclusions, including unique features of the case: Bitemporal hemianopia is commonly seen in pathologies affecting the optic chiasm, however tilted optic nerves are an alternative cause for this visual field defect. When coupled with clinical symptoms such as headache, exclusion of a compressive chiasmal lesion is necessary for a final diagnosis. References: 1. Vuori ML, Mäntyjärvi M. Tilted disc syndrome may mimic false visual field deterioration. Acta Ophthalmol. 2008 Sep;86(6):622-5. doi: 10.1111/j.1600-0420.2007.01117.x. 2. Sowka JW, Luong VV. Bitemporal visual field defects mimicking chiasmal compression in eyes with tilted disc syndrome. Optometry. 2009 May;80(5):232-42. doi: 10.1016/j.optm.2008.11.005. 3. Manor RS. Temporal field defects due to nasal tilting of discs. Ophthalmologica. 1974;168(4):269-81. doi: 10.1159/000307049. Keywords: Visual fields, Perimetry, Neuroimaging, Orbit/ocular pathology Financial Disclosures: The authors had no disclosures. Grant Support: None. Contact Information: Rikki Cunningham, [e-mail] 232 | North American Neuro-Ophthalmology Society