Classification of microphthalmos and coloboma

J Med Genet. 1993 Aug;30(8):664-9. doi: 10.1136/jmg.30.8.664.


A new classification of microphthalmos and coloboma is proposed to bring order to the complexity of clinical and aetiological heterogeneity of these conditions. A phenotypic classification is presented which may help the clinician to give a systematic description of the anomalies. The phenotype does not predict the aetiology but a systematic description of ocular and systemic anomalies improves syndrome identification. There are two major classes, total and partial microphthalmos, and a subclassification which follows the embryology of the anomalies. The aetiological classification consists of three classes: (1) genetic (monogenic and chromosomal), (2) prenatally acquired (teratological agents and intrauterine deformations), and (3) associations. Genetic disorders give rise to malformations; prenatally acquired anomalies are disruptions or deformations. The aetiological classification can be applied to other congenital birth defects and improves counselling of families. Recurrence risks vary considerably between the classes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Coloboma / classification*
  • Coloboma / etiology
  • Coloboma / genetics
  • Humans
  • Microphthalmos / classification*
  • Microphthalmos / etiology
  • Microphthalmos / genetics
  • Phenotype