Each cell in your body contains 23 pairs of chromosomes. These chromosomes contain the genes you inherit from your parents. Genes can have many variants and studies of whole sets of genes reveal that these variants may increase or decrease your risk of developing certain eye conditions. Each variant may increase or decrease your risk very slightly, but this can add up across several genes. Over the past 15 years, scientists have identified nearly 500 genes that contribute to eye diseases ranging from the common to the rare.