Do you need to identify the entire row in an eye chart to move to the next? 

Anyone who has had an eye exam is familiar with the Snellen letter chart that is most commonly used to test vision. Ideally we like someone to be able to read all of the letters in a row before moving on to the next one, however occasionally someone might miss one or two letters from one line, or be able to read only one or two letters from the next line. This is generally considered acceptable, and we will indicate in that person's exam note that they could read or missed those few letters (for example "20/25-2" or "20/40+1").