You wear your spectacles all day, but don't have bifocals or multifocal (Progressive) lenses.
You need them to see things in the distance, e.g. for driving, but can also leave them on for close vision.
You wear them most of the time for general everyday use.
Single Vision - Reading
You mostly need your spectacles to read things close to you: papers, documents etc., but do not need them to see things in the distance.
Single Vision - Computer work
You need these spectacles for when you're working on the computer or something else at arms length.
Multifocal
There is no line on the lenses of your spectacles but the bottom of the lenses is stronger for close work while the top of the lenses gives you clear distance vision.
Multifocals (Progressives) give you both distance and near vision.
Your prescription will contain a measurement called ADD.
