NAO Book + Test Review Book Latest Update 2026 |
Exam Prep | 100% Accurate Answers
1. A spectacle lens is prescribed at -10.00D. Provided that the lens is fit at a
vertesx distance of 10mm. A rigid contact lens fit on K for this patient would
require a power of:
-9.00D
-10.00D
-11.00D
-12.00D
2. A contact lens was ordered with a base curve of 7.85 mm but was received
back from the laboratory with a base curve measuring 7.80 mm. The base
curve of the actual lens is:
0.25 D flatter
0.25 D steeper
0.50 flatter
0.50 steeper
3. What is the significance of base curve measurements in contact lens fitting?
Base curve measurements are irrelevant to lens fitting.
Base curve measurements are used to calculate lens diameter.
Base curve measurements indicate the lens power required.
Base curve measurements help determine the fit of the lens on the
cornea.
,4. Which of hte following cannot be used as a lens inspection device?
Radiuscope
Lensometer
Diameter gauge
Distometer
5. If a patient with a rigid gas permeable contact lens fitting tight at 7.50 mm is
experiencing discomfort, how would you determine the appropriate new
base curve to recommend?
You would recommend the same base curve and suggest a different
lens material.
You would change the lens diameter instead of the base curve.
You would increase the base curve to 7.65 mm to ensure a tighter fit.
You would assess the fit and comfort, then consider adjusting the
base curve to a slightly flatter measurement, such as 7.55 mm,
based on the fitting characteristics.
6. What is the term used to describe the curvature of the lens that is critical for
fitting contact lenses?
Base curve
Lens diameter
Optical zone
Corneal radius
,7. If a patient has a K reading of 45.00/46.00 and requires a lens diameter of 8.5,
which of the following combinations would likely be appropriate based on
the Dyer Nomogram?
44.00/45.00 8.2 diameter
45.00/46.00 8.5 diameter
48.00/49.00 9.0 diameter
42.00/43.00 8.0 diameter
8. The CPC of a trial contact lens is 44.00 diopters and contains a power equal
to +14.87 D. The over refraction is equal to -1.62 D. What final lens power is
required if the CPC to be ordered is 43.62 diopter.
+13.87 D
+15.00 D
+12.62 D
+13.62 D
9. If a patient experiences corneal edema while wearing PMMA lenses, what
adjustment could be made to improve their comfort and corneal health?
Decrease the base curve measurement
Increase the lens diameter
Use a thicker lens material
Switch to CAB lenses
10. Which of the following is true about rigid, high-riding lid attachment lenses?
Annoying flare is exaggerated due to the larger optic zone.
Annoying flare can be minimized due to the larger optic zone.
, They are an excellent design for small, steep corneas
They will bump against the lower lid
11. Which factor is primarily associated with the interaction between the lens
and the cornea?
Refraction
K readings
Lens-cornea relationship
Lens thickness
12. The main supply of oxygen to the cornea is derived from the:
Endothelium
Collagen fibers
Tears
Basal membrane
13. Describe the significance of HEMA in the manufacturing of soft contact
lenses.
HEMA is used to create rigid lenses that do not conform to the eye
shape.
HEMA is a chemical that enhances the durability of gas permeable
lenses.
HEMA is a key material that provides flexibility and moisture
retention in soft contact lenses.
HEMA is primarily used in the production of corneal abrasions.
Exam Prep | 100% Accurate Answers
1. A spectacle lens is prescribed at -10.00D. Provided that the lens is fit at a
vertesx distance of 10mm. A rigid contact lens fit on K for this patient would
require a power of:
-9.00D
-10.00D
-11.00D
-12.00D
2. A contact lens was ordered with a base curve of 7.85 mm but was received
back from the laboratory with a base curve measuring 7.80 mm. The base
curve of the actual lens is:
0.25 D flatter
0.25 D steeper
0.50 flatter
0.50 steeper
3. What is the significance of base curve measurements in contact lens fitting?
Base curve measurements are irrelevant to lens fitting.
Base curve measurements are used to calculate lens diameter.
Base curve measurements indicate the lens power required.
Base curve measurements help determine the fit of the lens on the
cornea.
,4. Which of hte following cannot be used as a lens inspection device?
Radiuscope
Lensometer
Diameter gauge
Distometer
5. If a patient with a rigid gas permeable contact lens fitting tight at 7.50 mm is
experiencing discomfort, how would you determine the appropriate new
base curve to recommend?
You would recommend the same base curve and suggest a different
lens material.
You would change the lens diameter instead of the base curve.
You would increase the base curve to 7.65 mm to ensure a tighter fit.
You would assess the fit and comfort, then consider adjusting the
base curve to a slightly flatter measurement, such as 7.55 mm,
based on the fitting characteristics.
6. What is the term used to describe the curvature of the lens that is critical for
fitting contact lenses?
Base curve
Lens diameter
Optical zone
Corneal radius
,7. If a patient has a K reading of 45.00/46.00 and requires a lens diameter of 8.5,
which of the following combinations would likely be appropriate based on
the Dyer Nomogram?
44.00/45.00 8.2 diameter
45.00/46.00 8.5 diameter
48.00/49.00 9.0 diameter
42.00/43.00 8.0 diameter
8. The CPC of a trial contact lens is 44.00 diopters and contains a power equal
to +14.87 D. The over refraction is equal to -1.62 D. What final lens power is
required if the CPC to be ordered is 43.62 diopter.
+13.87 D
+15.00 D
+12.62 D
+13.62 D
9. If a patient experiences corneal edema while wearing PMMA lenses, what
adjustment could be made to improve their comfort and corneal health?
Decrease the base curve measurement
Increase the lens diameter
Use a thicker lens material
Switch to CAB lenses
10. Which of the following is true about rigid, high-riding lid attachment lenses?
Annoying flare is exaggerated due to the larger optic zone.
Annoying flare can be minimized due to the larger optic zone.
, They are an excellent design for small, steep corneas
They will bump against the lower lid
11. Which factor is primarily associated with the interaction between the lens
and the cornea?
Refraction
K readings
Lens-cornea relationship
Lens thickness
12. The main supply of oxygen to the cornea is derived from the:
Endothelium
Collagen fibers
Tears
Basal membrane
13. Describe the significance of HEMA in the manufacturing of soft contact
lenses.
HEMA is used to create rigid lenses that do not conform to the eye
shape.
HEMA is a chemical that enhances the durability of gas permeable
lenses.
HEMA is a key material that provides flexibility and moisture
retention in soft contact lenses.
HEMA is primarily used in the production of corneal abrasions.
