The genetics of eye disorders are being elucidated. The choice of the appropriate genetic tests, the interpretation of results and counselling issues are best carried out by specialised geneticists, but need to be understood by the ophthalmologist.What is achieved by chromosome analysis, FISH, chip screening, sequencing of genes, MLPA screening for deletions, and molecular karyotyping (array CGH) will be explained.Approaches to selected chromosomal, monogenic and multi-factorial disorders will be given with a list of disorders being tested via the local genetic centres.