CONTACT LENS Final Verified Multiple Choice
and Conceptual Actual Emended Exam
Questions With Reviewed 100% Correct
Detailed Answers
Guaranteed Pass!!Current Update!!
1. What is a contact lens? - ANSWER A thin lens considered to be a
medical device placed directly on the surface of the eye to correct vision.
2. Who first described the concept of a contact lens? - ANSWER Leonardo
da Vinci in 1508.
3. What significant advancement in contact lenses did John Herschel make? -
ANSWER He described a glass contact lens designed to match the shape
of the eye in 1827.
4. What was the first contact lens intended to correct vision? - ANSWER
Described by A. E. Fick in 1888.
5. What type of contact lens did Muller and Obrig construct in 1938? -
ANSWER The first plastic scleral contact lens.
6. What material did Kevin Touhy use to create the first plastic corneal lens? -
ANSWER PMMA (Polymethyl methacrylate) in 1947.
,7. What did Otto Wichterle develop? - ANSWER HEMA (hydroxyethyl
methacrylate), a key material for soft contact lenses.
8. How are contact lenses classified according to material? - ANSWER 1.
Hard (non-gas permeable, gas permeable) 2. Soft (hydrogel, silicone
hydrogel)
9. What are Terminator Eyes contact lenses designed to do? - ANSWER
They show images such as road directions or project text messages from
smartphones directly to the eye.
10.What does the Base Curve (BC) refer to in contact lenses? - ANSWER
The radius of curvature of the posterior zone.
11.What is the Optic Zone (OZ) in a contact lens? - ANSWER The posterior
central optic portion of the lens, indicating the size of the visually usable
portion.
12.How is Lens Diameter (LD) defined? - ANSWER It is a measure of the
maximum external dimension of a lens.
13.What does the Posterior Peripheral Curve Radius (PPCR) indicate? -
ANSWER It refers to the radius of the peripheral curve of the lens.
,14.What is the Peripheral Curve Width (PCW) in contact lenses? - ANSWER
The width of the posterior peripheral curve portion of the lens.
15.What does the Sagittal value (sag) measure? - ANSWER The distance
from the line drawn between the outer edges of the lens to the center of
the back surface.
16.What is the Optic Cap (OC) in a contact lens? - ANSWER The central
anterior optic portion of a lens.
17.What does the Optic Cap Radius (OCR) refer to? - ANSWER The radius of
the central anterior optic portion of a lens.
18.What is the Anterior Peripheral Curve Zone (APCZ)? - ANSWER The
anterior peripheral or lenticular portion of the lens.
19.Why is oxygen performance important in contact lenses? - ANSWER It
prevents corneal physiological processes from being compromised due to
oxygen deprivation.
20.What does dk (Oxygen Permeability) indicate? - ANSWER The quality of
the material that allows oxygen to move through it; higher dk means higher
oxygen content.
21.What are the classifications of dk values? - ANSWER Low dk: less than
30, Medium dk: 30-60, High dk: higher than 60.
, 22.What is Dk/t (Oxygen transmissibility)? - ANSWER It states how much
oxygen passes through the lens; thinner lenses allow more oxygen.
23.What is the minimum EOP (Equivalent Oxygen Performance) for daily wear
lenses? - ANSWER The minimum EOP for daily wear is typically set at a
specific threshold based on lens material.
24.What does corneal swelling indicate in contact lens wear? - ANSWER It
is a valid indicator of real-life clinical performance, measuring the percent
increase in corneal thickness.
25.What are the four measurements used to evaluate tensile properties of
contact lens materials? - ANSWER Tensile strength, Modulus elasticity,
Coefficient of elongation, and Tear strength.
26.What does tensile strength measure in contact lens materials? - ANSWER
It measures how much force can be applied to the material before it
breaks.
What does the modulus of elasticity refer to? - ANSWER It refers to the
flexibility of the material; lower values indicate more flexibility.
What does the coefficient of elongation indicate? - ANSWER It refers to how
far a lens material can be stretched before it breaks, expressed as a percentage.
and Conceptual Actual Emended Exam
Questions With Reviewed 100% Correct
Detailed Answers
Guaranteed Pass!!Current Update!!
1. What is a contact lens? - ANSWER A thin lens considered to be a
medical device placed directly on the surface of the eye to correct vision.
2. Who first described the concept of a contact lens? - ANSWER Leonardo
da Vinci in 1508.
3. What significant advancement in contact lenses did John Herschel make? -
ANSWER He described a glass contact lens designed to match the shape
of the eye in 1827.
4. What was the first contact lens intended to correct vision? - ANSWER
Described by A. E. Fick in 1888.
5. What type of contact lens did Muller and Obrig construct in 1938? -
ANSWER The first plastic scleral contact lens.
6. What material did Kevin Touhy use to create the first plastic corneal lens? -
ANSWER PMMA (Polymethyl methacrylate) in 1947.
,7. What did Otto Wichterle develop? - ANSWER HEMA (hydroxyethyl
methacrylate), a key material for soft contact lenses.
8. How are contact lenses classified according to material? - ANSWER 1.
Hard (non-gas permeable, gas permeable) 2. Soft (hydrogel, silicone
hydrogel)
9. What are Terminator Eyes contact lenses designed to do? - ANSWER
They show images such as road directions or project text messages from
smartphones directly to the eye.
10.What does the Base Curve (BC) refer to in contact lenses? - ANSWER
The radius of curvature of the posterior zone.
11.What is the Optic Zone (OZ) in a contact lens? - ANSWER The posterior
central optic portion of the lens, indicating the size of the visually usable
portion.
12.How is Lens Diameter (LD) defined? - ANSWER It is a measure of the
maximum external dimension of a lens.
13.What does the Posterior Peripheral Curve Radius (PPCR) indicate? -
ANSWER It refers to the radius of the peripheral curve of the lens.
,14.What is the Peripheral Curve Width (PCW) in contact lenses? - ANSWER
The width of the posterior peripheral curve portion of the lens.
15.What does the Sagittal value (sag) measure? - ANSWER The distance
from the line drawn between the outer edges of the lens to the center of
the back surface.
16.What is the Optic Cap (OC) in a contact lens? - ANSWER The central
anterior optic portion of a lens.
17.What does the Optic Cap Radius (OCR) refer to? - ANSWER The radius of
the central anterior optic portion of a lens.
18.What is the Anterior Peripheral Curve Zone (APCZ)? - ANSWER The
anterior peripheral or lenticular portion of the lens.
19.Why is oxygen performance important in contact lenses? - ANSWER It
prevents corneal physiological processes from being compromised due to
oxygen deprivation.
20.What does dk (Oxygen Permeability) indicate? - ANSWER The quality of
the material that allows oxygen to move through it; higher dk means higher
oxygen content.
21.What are the classifications of dk values? - ANSWER Low dk: less than
30, Medium dk: 30-60, High dk: higher than 60.
, 22.What is Dk/t (Oxygen transmissibility)? - ANSWER It states how much
oxygen passes through the lens; thinner lenses allow more oxygen.
23.What is the minimum EOP (Equivalent Oxygen Performance) for daily wear
lenses? - ANSWER The minimum EOP for daily wear is typically set at a
specific threshold based on lens material.
24.What does corneal swelling indicate in contact lens wear? - ANSWER It
is a valid indicator of real-life clinical performance, measuring the percent
increase in corneal thickness.
25.What are the four measurements used to evaluate tensile properties of
contact lens materials? - ANSWER Tensile strength, Modulus elasticity,
Coefficient of elongation, and Tear strength.
26.What does tensile strength measure in contact lens materials? - ANSWER
It measures how much force can be applied to the material before it
breaks.
What does the modulus of elasticity refer to? - ANSWER It refers to the
flexibility of the material; lower values indicate more flexibility.
What does the coefficient of elongation indicate? - ANSWER It refers to how
far a lens material can be stretched before it breaks, expressed as a percentage.
