Embodiments of the invention relate to single nucleotide polymorphisms (SNPs) in Thrombospondin 1 gene (THB-S1) that are herein linked to an increased risk for dry eye (also known as keratoconjunctivitis). The polymorphisms disclosed herein are directly useful for the diagnosis of an increased risk for dry eye, as well as for the determination of patient treatment pre- and post-surgery (e.g. pre and post refractive eye surgery) or in a patient having a condition associate with dry eye (e.g. diabetes, lupus, scleroderma, Sjogren's syndrome, thyroid disorders, vitamin A deficiency, and rheumatoid arthritis). Computer systems and medium are also enclosed. The SNPs can be present in unique combinations, or as specific haplotypes indicative of dry eye. The SNPs linked to an increased risk for dry eye include rs1478604, rs2228261, and rs2292305.