The Tono-Pen is a handheld device thatâs shaped like a large marker. It provides a digital readout of eye pressure. Your doctor can use it to touch your eye and measure pressure. Though useful in many cases, the Tono-Pen is considered less accurate than the Goldmann tonometer in people with normal corneas.
The English language has two types: British English and American English. Other variations such as Oxford English, Standard English, or other variants are mere adaptations of the two types (especially for consistency or reference use, e.g., in media or publication). British English.
from English Grammar Today. A standard language is a variety of language that is used by governments, in the media, in schools and for international communication. There are different standard varieties of English in the world, such as North American English, Australian English and Indian English.