ABO Certification Exam
Solved Questions With Revised
Correct Detailed Answers
1. Compound myopic astigmatism - ANSWER no longer simple because all
rays hit different spots on the retina, all falling too short (some further than
others)
2. Compound myopic astigmatism example - ANSWER -1.00-0.50*180
-3.00-1.25*045
3. Compound hyperopic astigmatism - ANSWER no longer simple because all
rays hit different spots, all falling beyond the retina(some further than others)
4. Compound hyperopic astigmatism example - ANSWER +1.00-0.50*180
+3.00-1.00*045
5.Mixed astigmatism - ANSWER some rays fall ahead of the retina while other
fall beyond it. vision will be poor in all areas.
6. Mixed astigmatism examples - ANSWER +1.00-2.00*045
+2.00-2.25*067
,7. Visible spectrum of light - ANSWER 400nm-700nm (nanometers)
6. refraction - ANSWER Bending of light(change of direction/speed), allowing
optical lenses to alter the bath of light rays
7. notation of "index of refraction" - ANSWER "n"
8. Examples of "n" - ANSWER 1.498,1.5,1.60,1.67,1.74 (higher =thinner the
lens)
9. Apex - ANSWER the pointy part of a prism
10. Base - ANSWER the bottom of a prism
11. Meniscus lens - ANSWER A lens having a convex front surface and a
concave back surface. (modern day optical lenses)
12. Converge (definition and lens type) - ANSWER to move toward one point.
plus lens
13. Diverge (definition and lens type) - ANSWER to move away from one
point. minus lens
14. Rays of light entering a prism always.... - ANSWER bend around the base.
,15. The object being viewed through a prism always... - ANSWER shift
towards the apex
16. The nominal lens formula - ANSWER DL=D1+D2 (dl is total power, d1 is
front surface power, d2 is back surface power)
17. Base Curve Theory - ANSWER front base needs to be as close to +6.00 as
possible.
18. Vogel's Rule: - ANSWER Rule-of-thumb for predicting base curves:
For plus powers:
Base = Sphere equivalent + 6.00
For minus powers:
Base = 1/2 spherical equivalent + 6.00
19. Aspheric - ANSWER front surface is tapered away from the center,
providing a thinner lens
20. Flat transposition - ANSWER The formula used to switch between the two
different ways of writing a prescription
21. Transpose this prescription -2.00+2.00*180 - ANSWER 0.00-2.00*090
22. Transpose this prescription +4.00-3.25*045 - ANSWER +0.75+3.25*135
, 23. Transpose this prescription -6.50+2.75*077 - ANSWER -3.75-2.75*167
prism - ANSWER used to altar the perceived image so the brain thinks its in
the right place.
if the prism position is altered... - ANSWER the images perceived position
changes
if prism thickness is changed.. - ANSWER the distance of the perceived object
will change
"PD" - ANSWER pupillary distance taken with the pupilometer
non-prism glasses have.. - ANSWER the OC sitting directly on their pupil
glasses with prism have.. - ANSWER the OC purposely moved away from the
pupil
having the OC moved away from the pupil is called - ANSWER Major
reference point (MRP)
abbe value - ANSWER An index to measure the chromatic aberration or
clarity of a lens material. good abbe vale is 40-50. bad is < 30
Solved Questions With Revised
Correct Detailed Answers
1. Compound myopic astigmatism - ANSWER no longer simple because all
rays hit different spots on the retina, all falling too short (some further than
others)
2. Compound myopic astigmatism example - ANSWER -1.00-0.50*180
-3.00-1.25*045
3. Compound hyperopic astigmatism - ANSWER no longer simple because all
rays hit different spots, all falling beyond the retina(some further than others)
4. Compound hyperopic astigmatism example - ANSWER +1.00-0.50*180
+3.00-1.00*045
5.Mixed astigmatism - ANSWER some rays fall ahead of the retina while other
fall beyond it. vision will be poor in all areas.
6. Mixed astigmatism examples - ANSWER +1.00-2.00*045
+2.00-2.25*067
,7. Visible spectrum of light - ANSWER 400nm-700nm (nanometers)
6. refraction - ANSWER Bending of light(change of direction/speed), allowing
optical lenses to alter the bath of light rays
7. notation of "index of refraction" - ANSWER "n"
8. Examples of "n" - ANSWER 1.498,1.5,1.60,1.67,1.74 (higher =thinner the
lens)
9. Apex - ANSWER the pointy part of a prism
10. Base - ANSWER the bottom of a prism
11. Meniscus lens - ANSWER A lens having a convex front surface and a
concave back surface. (modern day optical lenses)
12. Converge (definition and lens type) - ANSWER to move toward one point.
plus lens
13. Diverge (definition and lens type) - ANSWER to move away from one
point. minus lens
14. Rays of light entering a prism always.... - ANSWER bend around the base.
,15. The object being viewed through a prism always... - ANSWER shift
towards the apex
16. The nominal lens formula - ANSWER DL=D1+D2 (dl is total power, d1 is
front surface power, d2 is back surface power)
17. Base Curve Theory - ANSWER front base needs to be as close to +6.00 as
possible.
18. Vogel's Rule: - ANSWER Rule-of-thumb for predicting base curves:
For plus powers:
Base = Sphere equivalent + 6.00
For minus powers:
Base = 1/2 spherical equivalent + 6.00
19. Aspheric - ANSWER front surface is tapered away from the center,
providing a thinner lens
20. Flat transposition - ANSWER The formula used to switch between the two
different ways of writing a prescription
21. Transpose this prescription -2.00+2.00*180 - ANSWER 0.00-2.00*090
22. Transpose this prescription +4.00-3.25*045 - ANSWER +0.75+3.25*135
, 23. Transpose this prescription -6.50+2.75*077 - ANSWER -3.75-2.75*167
prism - ANSWER used to altar the perceived image so the brain thinks its in
the right place.
if the prism position is altered... - ANSWER the images perceived position
changes
if prism thickness is changed.. - ANSWER the distance of the perceived object
will change
"PD" - ANSWER pupillary distance taken with the pupilometer
non-prism glasses have.. - ANSWER the OC sitting directly on their pupil
glasses with prism have.. - ANSWER the OC purposely moved away from the
pupil
having the OC moved away from the pupil is called - ANSWER Major
reference point (MRP)
abbe value - ANSWER An index to measure the chromatic aberration or
clarity of a lens material. good abbe vale is 40-50. bad is < 30
