1.'Single vision' lenses are glasses
lenses that only offer ONE type of
vision correction. this means that they
are crafted to help people see better
at farther or shorter distances
(near sighted or far sightedness) But never Both!
2. 'Bifocal lens' lenses distance vision at the top half of the lens
and near vision at the bottom ; perfect if you need half with both.
This type of lens good things is bigger size for reading area
than progressive. but the line looks older.
3. 'Trifocal lenses' has three type of vision.
4.' Progressive lenses' also called multifocal lenses.
They are characterised by a gradient of increasing lens power .
It is most sought after lens when presbyopia begins.
But It is a litter more expensive than other lenses.