Mirror-image optic nerve dysplasia with associated anisometropia in identical twins

J Am Optom Assoc. 1997 May;68(5):325-9.


Background: Monozygotic (MZ) or "identical" twins arise from a single fertilized egg, which divides into two embryos at an early stage of development. As a result, MZ twins have identical genomes and are always of the same sex.

Methods: A case of optic nerve hypoplasia and anisometropia, in association with mirror-image presentation in a set of 12-year-old identical twins, is reported. The monozygotic twinning event responsible for identical twins--as well as the rare phenomenon of mirror imaging--is described.

Results: The combined occurrence of anisometropia and optic nerve hypoplasia in mirror-image presentation in a set of monozygotic twins provides a unique opportunity to study the genetic versus environmental influences on the development of optic nerve hypoplasia.

Conclusions: Although the cause of optic nerve hypoplasia remains unclear, its associated mirror-image presentation in this case suggests a possible genetic predisposition.

Publication types

  • Case Reports

MeSH terms

  • Anisometropia / diagnosis
  • Anisometropia / genetics*
  • Child
  • Diseases in Twins*
  • Evoked Potentials, Visual
  • Female
  • Humans
  • Optic Nerve / abnormalities*
  • Optic Nerve / pathology
  • Optic Nerve Diseases / diagnosis
  • Optic Nerve Diseases / genetics*
  • Twins, Monozygotic*
  • Visual Acuity
  • Visual Perception