Certified Paraoptometric (CPO) Exam
Questions and Answers Updated
2026/2027 Version | Verified Answers
1. What are additional curves on the lens that surrounds the optical zone
called? - ANSWER ✅ Peripheral curves
2. What is the center area of the lens that provides optical correction for the
patient's vision? - ANSWER ✅ Optical Zone
3. What is the measurement from edge to edge of the lens at the widest point
called? - ANSWER ✅ Overall Diameter
4. Soft or Rigid Lens? Made from materials that are oxygen-permeable but do
not absorb water. - ANSWER ✅ Rigid
5. Soft or Rigid Lens? Shorter adaptation period to the lens. - ANSWER ✅
Soft
6. Soft or Rigid Lens?
Once referred to as "hard" lenses. - ANSWER ✅ Rigid
7. Soft or Rigid Lens?
Generally provides sharper vision. - ANSWER ✅ Rigid
,8. Soft or Rigid Lens?
Made from materials that absorb water. - ANSWER ✅ Soft
9. Soft or Rigid Lens?
Always kept in solution when being stored. - ANSWER ✅ Soft
10.Soft or Rigid Lens?
This material lasts longer. - ANSWER ✅ Rigid
11.Soft or Rigid Lens?
Used on a disposable replacement schedule. - ANSWER ✅ Soft
12.Soft or Rigid Lens?
Patients are more likely to "feel" the lens on their eyes, especially during
adaptation period. - ANSWER ✅ Rigid
13.Soft or Rigid Lens?
When the lens becomes dry, it may crack or break. - ANSWER ✅ Soft
14.Add Power - ANSWER ✅ Additional plus power people need to view
things at arm's length.
15.Lensometer - ANSWER ✅ An instrument used to verify the spectacle lens
and contact lens prescription.
16.Single Vision - ANSWER ✅ Designed to correct vision at one distance.
,17.Spherical lenses - ANSWER ✅ Have the same power in all areas of the lens
and are used to treat myopia or hyperopia.
-2.00 or +1.00
18.Planocylindrical lenses - ANSWER ✅ Have no power in one area of the
lens and 90 degrees away from that area is the greatest power in the lens.
This lens is used to correct astigmatism.
0-1.00x90
19.Spherocylindrical lenses - ANSWER ✅ Combine a spherical and plano
cylindrical lens and are used to treat the combination of myopia or hyperopia
and astigmatism.
+2.00-1.00x180
20.Aspheric lenses - ANSWER ✅ Works well for spherical, but is inadequate
for Rx with Cyl. Also has a wider field of view, and a thinner lens profile.
21.Multi-focal lenses - ANSWER ✅ A single lens designed with multiple
powers to be used at different distances.
22.Bifocal lenses - ANSWER ✅ These lenses have powers for viewing at two
distances. In most situations, the top of the lens allows clear vision at
distance, and the bottom allows for clear vision at near.
23.Trifocal lenses - ANSWER ✅ These lenses have powers for viewing at
three distances. This adds an intermediate viewing.
, 24.Progressive Addition Lenses (PAL) - ANSWER ✅ Instead of having two or
three viewing distances, these lenses gradually change power starting at the
top of the lens to the bottom.
25.Glass - ANSWER ✅ Hardest surface, therefore the most scratch-resistant;
easiest to break or shatter.
26.CR-39 - ANSWER ✅ Less scratch-resistant, thought most lenses are treated
to improve scratch-resistance, but will still scratch more than glass. Thicker
than glass lenses, harder that glass to break.
27.Polycarbonate - ANSWER ✅ They are much harder to break or shatter.
They are a safety lens for children, athletes, and monocular patients. Thinner
than CR-39.
28.Trivex - ANSWER ✅ Mid-Index lens. Thinner than glass, CR-39 and Poly.
They are free from distortions and aberrations.
29.High-Index Lenses - ANSWER ✅ The thinnest lens materials and thus
provide a better cosmetic appearance for spectacles in higher prescriptions.
30.Eyewire - ANSWER ✅ The part of the frame that surrounds each lens. The
_______ holds the lens in place in the frame front.
31.Bridge - ANSWER ✅ The part of the frame that connects the two eyewires
together and supports the frame on the patient's nose.
Questions and Answers Updated
2026/2027 Version | Verified Answers
1. What are additional curves on the lens that surrounds the optical zone
called? - ANSWER ✅ Peripheral curves
2. What is the center area of the lens that provides optical correction for the
patient's vision? - ANSWER ✅ Optical Zone
3. What is the measurement from edge to edge of the lens at the widest point
called? - ANSWER ✅ Overall Diameter
4. Soft or Rigid Lens? Made from materials that are oxygen-permeable but do
not absorb water. - ANSWER ✅ Rigid
5. Soft or Rigid Lens? Shorter adaptation period to the lens. - ANSWER ✅
Soft
6. Soft or Rigid Lens?
Once referred to as "hard" lenses. - ANSWER ✅ Rigid
7. Soft or Rigid Lens?
Generally provides sharper vision. - ANSWER ✅ Rigid
,8. Soft or Rigid Lens?
Made from materials that absorb water. - ANSWER ✅ Soft
9. Soft or Rigid Lens?
Always kept in solution when being stored. - ANSWER ✅ Soft
10.Soft or Rigid Lens?
This material lasts longer. - ANSWER ✅ Rigid
11.Soft or Rigid Lens?
Used on a disposable replacement schedule. - ANSWER ✅ Soft
12.Soft or Rigid Lens?
Patients are more likely to "feel" the lens on their eyes, especially during
adaptation period. - ANSWER ✅ Rigid
13.Soft or Rigid Lens?
When the lens becomes dry, it may crack or break. - ANSWER ✅ Soft
14.Add Power - ANSWER ✅ Additional plus power people need to view
things at arm's length.
15.Lensometer - ANSWER ✅ An instrument used to verify the spectacle lens
and contact lens prescription.
16.Single Vision - ANSWER ✅ Designed to correct vision at one distance.
,17.Spherical lenses - ANSWER ✅ Have the same power in all areas of the lens
and are used to treat myopia or hyperopia.
-2.00 or +1.00
18.Planocylindrical lenses - ANSWER ✅ Have no power in one area of the
lens and 90 degrees away from that area is the greatest power in the lens.
This lens is used to correct astigmatism.
0-1.00x90
19.Spherocylindrical lenses - ANSWER ✅ Combine a spherical and plano
cylindrical lens and are used to treat the combination of myopia or hyperopia
and astigmatism.
+2.00-1.00x180
20.Aspheric lenses - ANSWER ✅ Works well for spherical, but is inadequate
for Rx with Cyl. Also has a wider field of view, and a thinner lens profile.
21.Multi-focal lenses - ANSWER ✅ A single lens designed with multiple
powers to be used at different distances.
22.Bifocal lenses - ANSWER ✅ These lenses have powers for viewing at two
distances. In most situations, the top of the lens allows clear vision at
distance, and the bottom allows for clear vision at near.
23.Trifocal lenses - ANSWER ✅ These lenses have powers for viewing at
three distances. This adds an intermediate viewing.
, 24.Progressive Addition Lenses (PAL) - ANSWER ✅ Instead of having two or
three viewing distances, these lenses gradually change power starting at the
top of the lens to the bottom.
25.Glass - ANSWER ✅ Hardest surface, therefore the most scratch-resistant;
easiest to break or shatter.
26.CR-39 - ANSWER ✅ Less scratch-resistant, thought most lenses are treated
to improve scratch-resistance, but will still scratch more than glass. Thicker
than glass lenses, harder that glass to break.
27.Polycarbonate - ANSWER ✅ They are much harder to break or shatter.
They are a safety lens for children, athletes, and monocular patients. Thinner
than CR-39.
28.Trivex - ANSWER ✅ Mid-Index lens. Thinner than glass, CR-39 and Poly.
They are free from distortions and aberrations.
29.High-Index Lenses - ANSWER ✅ The thinnest lens materials and thus
provide a better cosmetic appearance for spectacles in higher prescriptions.
30.Eyewire - ANSWER ✅ The part of the frame that surrounds each lens. The
_______ holds the lens in place in the frame front.
31.Bridge - ANSWER ✅ The part of the frame that connects the two eyewires
together and supports the frame on the patient's nose.
