Neuro-ophthalmologic manifestations of konzo

Jean Claude Mwanza, Désiré Tshala-Katumbay, Thorkild Tylleskär

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Konzo is a permanent spastic paraparesis of acute onset attributed to the effect of cyanogenic compounds from insufficiently processed bitter cassava in combination with low protein intake. In all studies of konzo, ophthalmologic complaints have been presented but only recently systematic studies of the neuro-ophthalmologic disturbances in konzo have been done. In this review, we see that about half the patients have an optic neuropathy with decreased visual acuity, alterations of the visual fields, atrophy of the temporal part of the retinal nerve fibre layer linked with temporal pallor of the optic disk. About half of the konzo patients also have abnormal visual evoked potentials, with both delayed latency and reduced amplitude. A small number of konzo patients have an ocular motor disturbance leading to a pendular nystagmus. The severity of the neuro-ophthalmologic involvement is not parallel to the severity of the motor disturbance in konzo. This may suggest that two different pathogenic mechanisms are involved.

Original languageEnglish (US)
Pages (from-to)491-496
Number of pages6
JournalEnvironmental Toxicology and Pharmacology
Issue number3
StatePublished - May 2005


  • Cassava
  • Cyanides
  • Konzo
  • Motor neuron
  • Nitriles
  • Ocular motor disturbances
  • Optic neuropathy

ASJC Scopus subject areas

  • Toxicology
  • Pharmacology
  • Health, Toxicology and Mutagenesis


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