four types of soft contact lens materials based on FDA classification

1. FDA Classification of
soft contact lens
By: sushmitha hebri

2. •The U.S Food and Drug Administration(FDA) has
classified soft contact lens materials according to
their water content and ionic charge.
•The groups were initially designed to deal with
how different lenses interacted with various lens
care products and to differentiate between lenses
which attracted varying amounts of protein
deposits from the tear film.
•This classification simplifies the large number of
possible soft lens materials into few groups

3. 1) Group 1: Low water content, non-ionic
polymers
2) Group 2: high water content, non-ionic
polymers
3) Group 3: low water content, ionic polymers
4) Group 4: high water content, ionic
polymers

4.  Ionic lens surface is ‘charged’ (usually negative)
 Non ionic lens surface is ‘neutrally charged’ or no
charge.
 The main reason to have an ionic surface contact
lens is to attract water into the lens ,thus older
high water content are ionic.
 Advantage of having ionic lens is , it is easier to
wet the contact lens.
 Disadvantage of having an ionic surface is that
deposits may adhere to the lens more readily.

5.  The groups and their features are listed in the table below:
Group 1
Low water , Non-
ionic
Group 2
High water ,
Non-ionic
Group 3
Low water ,
Ionic
Group 4
High water ,
Ionic
Lowest protein
deposition
Lower protein
deposition
Lower protein
deposition
Highest protein
deposition
Eg:
B+L iConnect
Annual
B+L Optima 38
Eg:
B+L Softlens 59
B+L Softlens daily
disposable
Eg:
B+L Purevision 2
Eg:
JnJ Acuvue lenses