Mirror-image optic nerve dysplasia with associated anisometropia in identical twins.
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.
Cidis
M B
MB
State University of New York, State College of Optometry, New York 10010, USA.
Warshowsky
J H
JH
Goldrich
S G
SG
Meltzer
C C
CC
D015858:Anisometropia / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D004200:Diseases in Twins; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D009900:Optic Nerve / Q000002:abnormalities* / Q000473:pathology; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000235:genetics*; D014430:Twins, Monozygotic; D014792:Visual Acuity; D014796:Visual Perception