- @Dlskidmore: I had the same question - see my talk page. You use <ref name=xxx>...</ref> , and then to refer back to it, you have another ref section with the same named tag, and and empty body. Divenal (talk) 11:30, 26 June 2020 (UTC)
@Dlskidmore: your ref says that there is no symmetry between left/right. But the 2007 review Read SA, Collins MJ, Carney LG (2007). "A review of astigmatism and its possible genesis". Clin Exp Optom. 90 (1): 5–19. doi:10.1111/j.1444-0938.2007.00112.x. PMID 17177660.CS1 maint: multiple names: authors list (link) seems to think there is
ASTIGMATISM IN RIGHT AND LEFT EYES There is widespread agreement that some degree of symmetry exists between the refractive errors of right and left eyes...
@Divenal: Feel free to add that there's some controversy and provide the reference with the competing view. Does that paper point to any evidence or just reference "widespread agreement"? Dlskidmore (talk) 17:12, 16 July 2020 (UTC)