Visual field loss in vigabatrin demonstrating bilateral tunnel visual fields. (Ravindran et al)

There are relatively few causes for tunnel visual fields (or “gun barrel” visual fields), which is a relatively common finding in neuro-ophthalmology. There are 8 major categories of tunnel visual fields, which can be determined systematically through careful history and examination. This differential diagnosis is adopted from Duane’s Clinical Ophthalmology.

4 Optic Nerve Causes of Tunnel Fields

End-stage glaucoma
End-stage papilledema (post-papilledema optic atrophy)
End-stage optic nerve drusen
Vigabatrin optic neuropathy

2 Retinal Causes of Tunnel Fields

Retinitis pigmentosa and RP-like conditions
Peripheral retinal scarring and degeneration (includes PRP scarring)

1 Intracranial Cause of Tunnel Fields (Bilateral)

Bilateral occipital lobe infarcts with “macular sparing” (sparing of occipital tips)

Functional Vision Loss

References

Glaser J. Chapter 5. Topical Diagnosis: Prechiasmal Visual Pathways. In: Duane’s Clinical Ophthalmology. In: Tasman W, Jaeger EA, eds. Duane’s Ophthalmology on CD-ROM, 6th Ed. Lippincott William & Wilkins, 2005.
Ravindran J, Blunbergs P, Crompton J, et al. Visual field loss associated with vigabatrin: pathological correlations. Journal of Neurology, Neurosurgery & Psychiatry 2001;70:787-789.

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