Anti-Reflective Lenses Flashcards
Which is a correct statement concerning light waves that are more than 20 feet for their source?
a.) They lose their magnetic property but retain their electrical property
b.) They become polarized and are propagated only in one direction
c.) They are propagated as concentric circles
d.) They have a flat wave front
d.) They have a flat wave front
What is the range of visible wavelengths the human eye is sensitive to?
380nm to 760nm
Which of the following occurs to the greatest degree when light encounters a lens surface?
a.) Changed to heat energy
b.) Reflected
c.) Absorbed
d.) Transmitted
d.) Transmitted
Lens reflections increase in brightness and intensity as _____
a.) The refractive index of the lens’ material becomes higher
b.) The front base curve of the lens steepens
c.) The thickness of the lens increases
d.) The angle of reflection decreases
a.) The refractive index of the lens’ material becomes higher
How much light does a 1.74 index lens reflect?
14.1%
On what optical characteristic are AR treatments based upon?
Destructive interference
What does the term broadband mean in regard to AR treatments?
A reduction of surface reflections over the entire visible spectrum
Which type of glare does AR treatment eliminate?
Distracting glare
Where is ultra-violet found in the electro-magnetic spectrum?
Above violet
When light is reflected back towards the wearer it can do what?
Compromise vision and reduce visual performance
Who is credited with being the inventor of AR treatment?
Carl Zeiss Company
In order for an AR lens treatment to be effective, its index of refraction must be ___ of the index of the material it is being coated upon
The square root
How thick are today’s modern AR lens treatments?
0.2-0.3 microns
What coating material was used to create early AR lenses?
Magnesium fluoride
Each layer of a modern AR treatment is composed of a different material of either ____
Silicon dioxide or a metal oxide
How do modern AR lenses prevent crazing of the AR treatment on plastic lenses?
A special hard coating is used that acts as a transition between the glass-like AR treatment and the plastic lens
What are the names of the methods that are used to place a hard coating on a plastic lens?
Spinning and dipping
How thick is the hard coating used on plastic lenses?
3 to 5 microns
A rainbow-like visual effect that can occur when an AR treatment is not properly index matched to the lens material it is coating upon is known as what?
Newton’s Fringes
The thickness of an AR coating must be ____ wavelength of the color in the spectrum it is attempting to reflect in order to be effective
1/4
An effective AR treatment eliminates what percentage of lens surface reflections?
99%
What is the life expectancy of a modern AR lens?
The life of the average prescription
How can an ECP know that an AR lens is tough enough for patient use?
If the lens passes the requirements of federal regulation CFR 801.410.
All of the following are features of modern AR treatments except:
a.) Easy to clean
b.) Non-electrical conducting
c.) Tough
d.) Durable
b.) Non-electrical conducting
An AR lens that repels oily deposits like facial oils and fingerprints is said to have ______ properties.
Oleophobic
If an AR lens beads water well, what property is it exhibiting?
Hydrophobic
Hard coating is the lens’ defense to ____ scratching problems
mild to moderate
Which AR treatment property is needed due to the triboelectric effect?
Anti-static
What did a study reported by the Journal of the American Optometric Association find about AR lenses?
That they help drivers by reducing daytime and nighttime glare
Which of the following is a correct statement about the findings in the University of Wales College of Cardiff study that investigated a patient’s recovery time to a dazzling bright light source with AR lenses?
a.) Hyperopes showed a 12% improvement
b.) Myopes showed a 50% improvement
c.) Hyperopes showed a 44% improvement
d.) Myopes showed a 38% improvement
b.) Myopes showed a 50% improvement
According to Stetson, how much more light does a 65-year-old need in relation to an 18-year-old?
3.0 times
What did Kirkland and Copeland’s study conclude?
That AR lenses can be used for post-cataract patients with intra-ocular lenses to give them maximum light and a decrease in glare transmission following surgery
What percentage of AR lenses are sold in Japan?
98%
Why is it important for sunglasses to have an AR treatment?
Because dark lenses accentuate the images reflected off the lenses due to their dark color
In a study conducted by Essilor, how many study participants who did not purchase AR lenses stated that the reason for not buying them was because they were not offered by the ECP?
90%
Why is it important to inform a patient about AR lenses before they enter the examination room to see the doctor?
It will help patients begin thinking about their lifestyle needs and how AR lenses can benefit them
Why is packaged pricing a good sales technique?
It helps avoid lens sticker shock
According to this Unit, what is one of the most effective methods of helping patients understand the benefits they will receive from choosing AR lenses?
Demonstrate them
A carefully crafted statement that contains all the information you need to mention for a particular product in a clear and concise manner is known as what?
Script
What is a recommendation from the AR committee concerning polishing lenses prior to AR treatment?
During a two-step fining system, it is suggested that compensated fining pads be used to ensure curve radius
Which test is used to measure the amount of haze induced in an AR lens?
The BYK Gardner Haze-Guard test
Which test assesses crazing and/or delamination of the AR treatment?
The cross-hatch adhesion test
Which test is designed to determine the extent to which an AR treatment will recover following increases in temperature in a non-humid, dry heat environment?
The craze/heal test
Which test mechanically rubs the lens using a 5-lb. weight?
The anti-static test
What does the Bayer Test assess?
The AR treatment’s resistance to scratching
Which of the following is NOT a test used in the RLS test series conducted by COLTS Laboratories?
The delamination test
What causes a high contact angle measurement?
High surface tension
Why is it important for an ECP to read the material the manufacturer produces about their AR products?
It contains information and claims that will help assess the features and benefits of the products.
