Lens Design?

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.

 distance(far)  intermediate(computer) 

 and near(reading)


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.