Forms of opthalmic lenses in daily practice.

1. FORMS OF LENSES
FAHEEM KV
OPTOMETRY
RGUHS

2. َّ‫الر‬ ِ‫ن‬ ٰ‫م‬ْ‫ح‬َّ‫الر‬ ِ‫هللا‬ ِ‫م‬ ْ‫س‬ِ‫ب‬ِ‫م‬ْ‫ي‬ِ‫ح‬

3. 1) Convex lenses (Plus lens)
a)Equiconvex
b)Biconvex
c)Planoconvex
2) Concave lenses (Minus lens)
a)Equiconcave
b)Biconcave
c)Planocancave
3) Periscopic lens
4) Meniscus lens

5. 1) Convex lens
a)Equiconvex lens
Positive focal power of the lens is divided
equally in each surface is called equiconvex
lenses.
eg: both surface having +2.00D
both surface having +3.00D

6. b) Biconvex lens
Both surface of the lens is in convex form
but not in equal power always.
eg: one surface having +3.00D and other
surface having +2.00D

7. c)Planoconvex lens
The back surface of the lens is plano or
zero power. But all the positive power is
produced by the front surface.
this form of lenses are called as
Planoconvex lenses.
eg: One surface having +2.00D and other
surface having power zero.

8. 2) Concave lenses
a)Equiconcave lens
Negative focal power of the lens is divided
equally in each surface is called
equiconcave lens.
eg: Both surface having -2.00D
Both surface having -2.50D

9.  b) Biconcave lens
Both surface of the lens is in concave form
but not in equal power always.
eg: one surface having -2.00D and other
surface having -1.00D.

10. c) Planoconcave lens
The back surface of the lens is plane or
zero power. But, all the negative power is
produced from front surface.
This form of lenses are called as
Planoconcave lenses.
eg: one surface having -2.00D and other
surface having zero power.

11.  3) Periscopic lens
In this lenses, one surface of the lens having
positive power and the other surface having
negative power.
This lens having a base curve of (+or-)1.25D.

12. 4) Meniscus lens
One surface of the lens having positive power
and the other surface having negative power.
This lenses are similar to periscopic lenses, but
this lens having a base curve of (+or-)6.00D.

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