Adult-onset cataract (AOC) is a major ocular health problem and is the number one cause of blindness in the world. It is interesting to note that if the development of cataract is delayed by 10 years, the number of cataract surgeries needed would decrease by 45%. To prevent or delay cataract, the molecular pathological mechanisms underlying the lens change have to be understood, and this requires that the genes involved in such mechanisms should be identified. Hence, in this study we aim to identify AOC families which show a clear mendelian inheritance pattern, as only these families would be ideal for mapping the genes responsible. Over a period of 8 months, from September 1995-April 1996, 17 families with two or more affected members were identified. Segregation analysis showed autosomal dominant inheritance in multiple affected families. We propose to map the genes responsible for cataract in these families by linkage analysis and mutational screening of candidate genes.