1. GP Materials & GP Care Solutions - Advanced Contact Lenses Fall 2026

What does Dk refer to?

Oxygen permeability

Silicone concentration will (increase/decrease) O2 in the lens

Increase

Fluorine will (increase/decrease) O2 solubility

Increase

What is Dk/t?

O2 transmissibility

What is the clinically most valuable value for oxygen permeability?

Dk/t

What is GP specific gravity?

ratio of the density of the lens material to the density of water

What is a low GP specific gravity value?

1.10 or less

What is a medium GP specific gravity value?

1.11 to 1.2

What is a high GP specific gravity value?

>1.2

Can specific gravity play a role in success of GP Lens fits?

Yes

High plus lenses are thick. What will a high specific gravity cause?

encourages the lens to sit inferior

Prism ballasted lenses will have a (high/low) specific gravity

high

If you want specific gravity to be irrelevant, how should you design a lens?

Make the lens as thin as possible, or use a lower SG

Wetting Angle - Hydrophobic Material (Pic)

Wetting Angle - Hydrophobic Material (Pic)

Wetting Angle - Hydrophilic Material (Pic)

Wetting Angle - Hydrophilic Material (Pic)

Which is more wettable?

High or low wetting angle

low wetting angle

What is the material hardness scale used for RGP buttons?

Rockwell Hardness Method

What is the Rockwell Hardness Method show?

Shows resistance to cmpression

What is the material hardness scale used for finished RGP lenses?

Shore D Hardness

What does the Shore D Hardness scale show?

Resistance to scratching

Is there a correlation between modulus and Dk?

Yes -- High Dk will correlate to a low modulus and vise versa

*inverse relationship

What is special about Menicon Z and Infinite lenses regarding their modulus and Dk?

These lenses have a slightly higher modulus than you would expect based on their Dk. These lenses can resist flexure

What are the surface treatments for RGPs that are discussed in this module?

-plasma coated

-plasma treated

-polyethylene glycol (hydra-PEG)

True or False:

Many plastics inherently do not wet

true

What is the purpose of plasma treatments on the surface of RGPs?

-Plasma treatment can modify the surface w/o changing the bulk properties

-Modify the chemical and physical structure of the surface

-Will remove impurities

Do plasma treatments on RGP lenses improve the wetting angle?

Yes -- lower wetting angle present after treatment

Do plasma treatments of RGP lenses smooth the surface of the lens?

Yes

Are RGPs typically plasma coated?

No -- this is for soft lenses. RGPs can have a plasma treatment but are usually NOT coated

What is Hydra-PEG?

Covalently bonded hydrophilic coating for soft, GPs, and hybrid lenses

What are the solutions that are compatible with HydraPEG treatment?

-Tangible Clean

-Boston Simplus

-Unique pH

-Clear Care

-Clear Care Plus

What are the solutions that are NOT compatible with HydraPEG treatment?

-Progent

-Boston Advance Cleaner

-Optimum CDS

-Boston Enzymatic Cleaner

What was the 1st CLs material used?

PMMA

What is PMMA?

First plastic available that had good optical properties

What are the pros of PMMA?

-Clarity

-Durable

-Scratch resistant

-Maintains shape well

-Deposit resistant

What are the cons of PMMA?

-No O2 permeability

-Hypoxic corneal complications likely

What are the possible adverse events when wearing PMMA lenses?

-Polymegethism and Pleomorphism

-Corneal Edema nad Corneal Exhaustive Syndrome

-Corneal Neovasc

RGP material that is not much better than PMMA but has Dk 4-6 and is more flexible

Cellulose Acetate Butyrate (CAB)

What was the goal of silicone acrylates for RGP lenses?

Eliminate or minimize edema related to PMMA

What are the pros of silicone acrylates for RGP lenses?

Better Dk (10 to 20) than CAB and PMMA

What are the cons of silicone acrylates for RGP lenses?

-Hydrophobic d/t silicone

-Prone to lipid and protein deposition

-Rapid drying, redness, inconsistent vision

Higher Dk silicone acrylates have what cons?

-crazing

-warpage

-deposits

-brittleness

2nd generation silicone acrylates have more silicone in their formulation. What is the effect of this?

-higher Dk

-worse wettability

What is the effect of adding methacrylic acid to RGP formulation?

-increases surface ionicity (more protein deposits)

-improves wettability

Is there a limit to the silicone: MA ratio?

Yes -- the lens will start to become too soft and not wettable with increases ratio

Fluoroalkyl methacrylates are similar to silicone acrylates but include what?

fluorine

What are the properties of Fluoroalkyl methacrylates that are beneficial?

-non stick properties

-O2 permeability is good

Many modern GP materials are made of what material?

Fluoro-Silicone Acrylates

Silicone allows ________

O2 diffusion

What is the effect of silicone in GP formulation?

Makes the material soft and hydrophobic

What does fluorine improve in a GP lens?

O2 solubility

What does fluorine allow for in a GP lens?

-higher Dk with less silicone

-More wettable material

Dk by Rigid Lens Type (Pic)

**highest Dk in Fluorine-Silicone Acrylates, lowest in PMMA and CAB

Dk by Rigid Lens Type (Pic)

What are the acceptable applications of Low Dk Fluorine-Silicone Acrylate GP lenses?

-Daily wear corneal lenses

-Myopia

-Toric lenses

-MF lenses

-Irregular cornea

Why can we get away with low Dk corneal GP lenses in daily wear?

We get more tear exchange & O2 delivered to the cornea with GP lenses

What are the acceptable applications for High Dk Fluorine-Silicone Acrylate GP lenses?

-Daily wear corneal lenses

-Hyperopia (moderate +)

-Toric

-MF

-Irregular cornea

-Thicker lens design

What are the acceptable applications for Hyper Dk Fluorine-Silicone Acrylate GP lenses?

-Any daily or overnight wear

-Scleral lenses

-OrthoK

-Thick lenses

What are the acceptable applications for Ultra Dk Fluorine-Silicone Acrylate GP lenses?

-Scleral lenses

-OrthoK

-Thick lenses

GP Materials that are Approved for Extended Wear are FDA Class ______ devices

III

Describe Menicon Z lenses

-Fuoromethacrylate + Siloxyanylstyrene + Crosslinkers + UV absorber

-Rockwell Hardness = 60

-Plasma treated

-Higher modulus than you would expect for the higher Dk lens

What is the 2 bottle GP care solution on the market this is discussed in this module?

Boston Advance Cleaner & Boston Advance Conditioning Solution

What is the multipurpose GP care solution on the market this is discussed in this module?

-Boston Simplus

-Unique pH

What is the Dual indication GP care solution on the market this is discussed in this module?

-Hydrogen Peroxide (Clear Care)

-Tangible Clean

Describe Boston Advance Cleaner which is a part of the 2 bottle GP Care System

Contains surfactants, Microabrasive material and visibility tint. NEVER PUT IT DIRECTLY INTO THE EYE. Needs rinsed with saline 1st

Boston Advance Cleaner should be rinsed with _____ before put into patients eye

saline/MP solution

Describe Boston Advance Conditioner which is a part of the 2 bottle GP Care System

Contains disinfection and conditioning solution. Can be put directly into the eye. Not to be used w/o Part 1 of the Care System (Cleaner)

Do GP lenses significantly uptake preservatives from solutions?

No

Do soft lenses significantly uptake preservatives from solutions?

Yes

There are ____x less preservatives in soft lens solution compared to GP lens solution

~4

Can GP solutions cause a toxic response with SCLs?

Yes

Describe Boston Simplus MultiAction Solution as a GP Care System

Contains cleaners, disinfectants, and conditioning agents all in 1 bottle

How to use Boston Simplus MultiAction Solution on GP lenses

1) Fill the case with fresh Simplus solution

2) Soak the lenses overnight to help loosen debris

3) Remove lenses from case, rub both sides with the solution for 20s

4) Rinse w/ Simplus

Describe Unique pH Solution as a GP Care System

Contains cleaners, disinfectants, and conditioning agents all in 1 bottle

How to use Unique pH Solution on GP lenses

1) Rub each side w/ 2-4 drops of solution

2) Rinse each side of the lens

3) Store lenses in fresh solution for 4h

Do GP Solutions have good cleaning capabilities?

Yes -- usually between 82-96% cleaning

Do GP Solutions have good disinfectant capabilities?

Yes -- disinfect against Staph, Serratia, Candida, Pseudomonas, and Fusarium

____ solution may be slightly less effective for cleaning ability compared to other GP lens solutions

Unique pH

Describe Alcon ClearCare Plus as a GP Care System

Cleaning + Disinfectant w/ Hydrogen Peroxide 3% + Conditioning

How to use Clear Care Plus Solution on GP lenses

1) Remove each lens and rinse for 5 sec

2) Open container, place lens in

3) Fill to line with Clear Care

4) Soak for minimum 6h

5) Remove lenses and place on the eye

What are the benefits of using Clear Care solution for GP lens care?

-Lipid removal

-Protein removal

-GP Disinfection

What is Tangible Clean Solution useful for?

Cleaning, Disinfection, and Conditioning

**compatible with HydraPEG material

How to use Tangible Clean Solution on GP lenses

1) 3 drops of tangible clean

2) Rub each side for 15-30sec

3) Rinse

4) Store at least 6h

What is Progent Solution for GP lens care?

-A = sodium hypochlorite bleach

-B = Potassium bromide as a powerful oxidizing solution (protein removal)

-Third vial = saline to rinse the mixture

How to use Progent Solution on GP lenses

1) Mix A + B vials

2) Soak 25 min

3) Rinse with saline vial

What is Progent Solution useful for?

-protein removal

-lipid removal

-antimicrobial

What is Miroflow solution useful for?

20% isopropyl alcohol for lipid and mucin removal; good at disinfection

What is Boston Lab cleaner used for?

-Only for lab and professional use

-Great for heavily deposited lenses

-Cannot be used regularly

Will extended soaking in Boston Lab Cleaner damage the RP lenses?

yes