A.2mm B.3mm C.4mm D.1mm
A.15% B.25% C.35% D.45%
A.顳下方距角膜4~5mm處 B.鼻下方距角膜4~5mm處 C.顳上方距角膜4~5mm處 D.鼻上方距角膜4~5mm處