OBJECTIVE Major advances and developments in corneal molecular genetics have revolutionized our fundamental understanding of corneal dystrophies. At the same time, this knowledge is allowing for improved ways to classify these dystrophies. New genes and mutations responsible for corneal dystrophies are being discovered at an accelerating rate. Ophthalmologists must keep abreast of all the new information, as our basic understanding as well as our classification systems are changing. We present a current review of the genetics of corneal dystrophies. RESULTS After the discovery of the BIGH3 (TGFbeta1) gene responsible for several corneal dystrophies, there has been an explosion of new information. New mutations are discovered every day for many of the corneal dystrophies located on the BIGH3 gene. In addition, new genetic sites are also being realized. Additionally, corneal dystrophies which have never been linked to any genetic site are now beginning to be uncovered. CONCLUSIONS As new mutations and genetic sites are discovered for the various corneal dystrophies, new information will arise, allowing researches to develop innovative methods to study these gene products and their function. This will open the door for novel diagnostic and therapeutic approaches. Ultimately, gene therapy may be possible, leading to cures for these sight-threatening diseases.