Assuming A represents preterm birth, A1 represents VEGF, B represents ROP, and C represents the risk of myopia, we can summarize the relationship as follows: A leads to A1, which then leads to C, rather than a confounding relationship where A directly causes C while also causing B to lead to C. This could potentially explain the results of Mendelian randomization analysis and confusion analysis. The gene discussed is VEGFA; the disease is myopia.