S3 methods for VA classes "snellen", "logmar" and "etdrs". snellen is always also a character class- because it is more categorical than continuous. logmar and etdrs are both numerics (logMAR is double, etdrs is integer).
S3 methods for blink class
# S3 method for snellen
print(x, ...)# S3 method for logmar
print(x, ...)
# S3 method for etdrs
print(x, ...)
# S3 method for blink
print(x, ...)
object of class "blink"
arguments passed to print.default
No return value, called for side effects (printing)