SIX1 and open-angle glaucoma: To date, three studies have reported significant associations of SIX1/SIX6 polymorphisms to cpRNFL thinning in the upper and lower sectors—but not the nasal and temporal sectors—in 30 POAG cases32, 1,243 population controls31, and 231 other participants consisting of 20% normal, 44% of suspected glaucoma, and 36% confirmed glaucoma cases30.