This document discusses different designs of progressive additional lenses (PALs). It describes hard and soft, symmetrical and asymmetrical, mono and multi designs. Conventional PALs add power on the front surface while internal PALs add power to the back surface. Digital PALs and freeform technology allow for smoother progression of power. Specialty PALs include short corridor and near variable focus lenses tailored for specific tasks. The document provides details on characteristics and advantages and disadvantages of each PAL design.

1. Designs of PAL’s
Optom. Sagar Kalamkar
M. Optom 1st year
Bharti Vidyapeeth ( Deemed University ) medical
college
School of Otometry

2. Designs
 Hard and soft
 Advanced soft
 Symmetrical and Asymmetrical
 Monodesign and multidesign
 Conventional PAL
 Internal PAL
 Digital PAL
 Freeform Technology

3. Hard and soft design
• Distance and near zone
• Intermediate zone
• Area of astigmatism
• Amount of astigmatism
• Adaptation time

4. Advanced Soft Design
• Area of Astg. Is lesser than soft
• Amt. of astig. Is lesser than hard
• Amt. of astig. Is equal to soft
• Distance is greater than soft
• Intermediate is greater than hard
• Near is greater than soft

5. Symmetrical design
• Add is straight
down from distance
optical centre
• No right and left
lenses
• Required rotation
to achieve desire
inset for near
( 10-12-15 ) degree

6.  Advantages :-
- We can give the inset according to
patient
- Easy to manufacture
 Disadvantages :-
- Toric prescription can not be design
- As the wearers looks too the side
they
will experience different power

7. Asymmetrical Design
 Lenses have pre-
set inset for near
 Different lenses for
right eye and left
eye

8. Symmetric
design
Asymmetric
Design

9.  Advantage :-
- Toric Prescription is design
- No need of rotation of lens
- Pt. will not produce experience of
different power when pt. look side
 Disadvantages :-
- Fixed inset may not match with
patient
required inset

10. Mono Design
• In this lenses there is a linear
relationship between ADD powers in a
lens series
• With mono lens design , PAL’s the
amt. of unwanted astigmatism is
proportional to the ADD power
• It classify hard and soft

11. Multi-design
• According to ADD
power lens design
change
• It start from soft
design for low ADD
power
• The ADD power
increase it will turn to
hard design lens
• NA changes design
from soft, moderate
hard and hard

12. Conventional PALs :-
• ADD on front aspheric surface of lens
• Back surface for DRx
• Top portion of front surface of lens is
consider as BC for DRx

13.  Advantages :-
• We can make any power and cly.
Prescription as it is B. toric lens
 Disadvantage :-
• Reduces field of view by 10˚

14. Internal PALs :-
• Not for indoor
• ADD is given on back surface
• Front surface is kept constant
• Design provides a field of vision that is
30˚ wider than a front side progressive
lens

15. Advantages :-
• Increase the field of view by 10˚
Disadvantage :-
• Plus cly. prescription easy to
manufacture as minus cly. Prescription
• Limited power is available

16. Digital PALs :-
• Rate of progression of power is
in+0.12D or lesser 0.25D
• Power variation is continuous or
smooth progression of power
Can be Can be
Conventional Internal
-Add on front - Add on
back

17. Free form Technology
 Position of wear/as worn lens :-
It include :
- Pentoscopic tilt
- vertex distance
- An asperic or atoric surface to
correct Oblique astigmatism.

18.  When ordering the lens the sphere, cly.
and axis along with vertex distance and
pentoscopic tilt measurement are given
 Manufacture return the lens with orignal
order prescription of sph. , cly. And axis
as well as new sphere new cly. And axis
and also add power based on calculation
e.g. Original order
-4.00DS/-0.25DC×45˚
+2.00D ADD
New order
-3.96DS/-0.27DC×36˚
+1.82D ADD

19.  Atoric progressive :-
- Do not necessary include VD and PT
but
may have an atoric surface.
- Design include shamir, autograph,
and
zeiss shot, varilux physio 360˚
- Varilux physio is design using
wavefront

20.  Personalized progressive :-
- This kind of progressive using free
form technology the progressive optic
are as per individual needs and habits.
- e.g. varilux Ipseo matches the unique
head and eye movement habits of the
wearer
- Some individual are head turners
while others are eye tarners

21.  Speciality Progressive :-
- Truly for specialized task
- Will not be used for full-time wear
- Also called as occupational pals
1. Short corridor progressive lenses :
• This progressive lens allows fitting in a
frame with small vertical dimension
• They have faster transition between the N and D portion of
lens
e.g.
- Hoya summit imprened design (14mm )
- Varilux ellipse (14-18mm )
- shamir piccolo (16mm )
- Rodenstock Progressive (16mm )

22. 2. Near variable focus lenses :-
- Recommended for people who need
intermediate and near zone more
- This PALs has longer progressive
zone
- Power :
e.g. Taking a lens with no distance
correction and +2.00D Add

23.  Reference :-
- System for Ophthalmic Dispensing
( Author : Clifford brooks , Irvin M.
Borish)