On Saturday, December 29, 2018 at 3:51:01 AM UTC-5, Paul Schlyter wrote:

many
optalmophologists may operate with too limited resources so they may
not be able to afford an eye test room which is large enough. If so,
they should report normal visual acuity as not 20/20 but instead as
15/15 or perhaps even 10/10 depending on how large a test room they
had access too.

Mirrors.