Download ABO Certification Exam Prep: Ocular Anatomy, Optics, and Lenses and more Exams Ophthalmology in PDF only on Docsity!
National Certification Organization
for Opticians
ABO American Board of Opticianry
Basic ABO Certification Exam
Course Title and Number: Basic ABO Certification Exam
Exam Title: Certification Exam
Exam Date: Exam 2025- 2026
Instructor: [Insert Instructor’s Name]
Student Name: [Insert Student’s Name]
Student ID: [Insert Student ID]
Examination
180 minutes Instructions:
1. Read each question carefully.
2. Answer all questions.
3. Use the provided answer sheet to mark your responses.
4. Ensure all answers are final before submitting the exam.
5. Please answer each question below and click Submit when you
have completed the Exam.
6. This test has a time limit, The test will save and submit
automatically when the time expires
7. This is Exam which will assess your knowledge on the course
Learning Resources.
Good Luck!
Ctrl + Click ✅ ORDER NOW ✅ Follow Link & Get Instant Expert Help
ABO American Board of Opticianry
ABO Certification Exam Prep Study Guide |
100% Pass Guaranteed | Graded A+ |
Read All Instructions Carefully and Answer All the Questions Correctly Good Luck: -
Ultimate
The ^^ ABO Study Guide
Version 2/2025-
How to Pass the ABO:
The ABO is based on concepts. To pass the ABO you need grasp the
concepts. The concepts are quite basic and you will pass the exam if
you apply:
Memorization: Good old fashioned memorization. Study until you have the
concepts memorized. Use flash-cards, quiz sessions and study.
Practice: Work the examples given five, ten, fifteen times or until you can
see the patterns.
Visualization: Close your eyes and picture the concepts in your mind.
Picture them in practice and in three-dimensions. Practice it!
Drawing: You are given scrap paper for a reason. USE IT! If you do not draw
✅ ORDER NOW ✅
- Chapter 1: Ocular Anatomy................................................................................................
- The Structure of the Eye
- The Oculomotor Muscles of the Eye
- Refractive Errors
- Chapter 2: Basic Optical Principles...............................................................................
- Light and the Electromagnetic Spectrum
- Refraction
- The Index of Refraction “n”
- Diopter/Prism Diopter
- Lenses as Prisms
- Lens Power and Lens Power Formulas
- Chapter 3: Lens Form.........................................................................................................
- Sphere
- Cylinder
- Axis
- Aspheric Lens Design
- Flat Transposition
- The Optical Cross
- Prism
- Optical Center Verses Major Reference Point
- Working with Prism Prentice’s Formula
- Compounding Prism - Canceling Prism
- Prism Power & Meridian
- Chapter 4: Lens Options....................................................................................................
- Lens Materials
- Lens Material & Thickness
- AR or Non-Glare Coatings
- Photochromics: (Changeable Tint Lenses)
- Polarization
- Tinting
- Multifocals
- Progressives
- Slab Off
- Chapter 5: The Written Prescription.............................................................................
- Primary prescription information explained
- Conversion of a prescription with an add power provided to single vision readers
- Chapter 6: Frames...............................................................................................................
- How Frames Are Measured
- The Parts of an Eyeglass Frame
- Frame Materials
- Verifying frame and lens parameters and other physical characteristics
- Standard Alignment
- Measuring
- Applying Product Knowledge
- Dispensing a complete pair of glasses
- Trouble shooting
- Chapter 7: Tools...................................................................................................................
- The Lensmeter
- How to focus a lensometer for individual use
- Lens Clock
- Ophthalmic Tools, Instruments & Equipment
- Verification
- Verifying Prescribed Prism
- Chapter 8: Regulations & Standards............................................................................
Light enters the eye through the transparent, dome shaped cornea. The cornea consists of five distinct layers:
- The outer most layer is the epithelium which rests on Bowman’s membrane
- The next layer, which acts as a protective barrier, is Bowman's Membrane
- The stroma which is between the two membranes makes up 90% of the thickness of the cornea
- Descemet's Membrane separates the stroma and the endothelium.
- The inner most layer, the endothelium, removes water from cornea, helping to keep the cornea clear. Memory Hint: B comes before D and think “end” for endothelium. From the cornea, light passes through the pupil. The amount of light allowed through the pupil is controlled by the iris , the colored part of the eye.
The iris has two muscles:
- The dilator muscle which opens the iris allowing more light in
- The sphincter muscle which closes the iris The iris has the ability to change the pupil size from 2 millimeters to 8 millimeters. Just behind the pupil is the crystalline lens. The purpose of the lens is to focus light on the retina. The process of focusing on objects based on their distance is called accommodation. The closer an object is to the eye the more power is required of the crystalline lens to focus the image on the retina. The lens achieves accommodation with the help of the ciliary body which surrounds the lens. The ciliary body is attached to lens via fibrous strands called zonules. When the ciliary body contracts, the zonules relax allowing the lens to thicken, adding power, allowing the eye to focus up close. When ciliary body relaxes, the zonules contract, drawing the lens outward, making the lens thinner, and allowing the eye to focus at distance. No time like now to start memorizing some things. Give this a try for practice: The Layers of the Cornea Match
A Stroma
B Endothelium
C Epithelium
D Descemet’s
Membrane
E Bowman’s
Membrane
J – Cornea: The clear lens or structure that covers the iris or the colored part of the eye. The cornea is the first major structure that refracts light as it enters the eye. It has no blood supply and gets all of its oxygen directly from the air. K – Pupil: The opening created by the iris changing size. L - Sclera: In layman terms, "the whites of your eyes.” The sclera is a thick, tough and fibrous layer that provides the structure of the entire eyeball. M – Limbus: Where the cornea blends into the sclera. Q – Iris: The colored area under the cornea that opens and closes to regulate light entering the eye. H - Palpebral Conjunctiva: The layer that covers the eyelids. I - Ocular or Bulbar Conjunctiva: The layer that covers the exposed portions of the eye. Your Turn – See if you can label the following. Eye Anatomy Name the parts
J K L M N Q
The Oculomotor Muscles of the Eye Lateral Rectus: Rotates eye laterally or out towards the ear. Attaches directly to the side of the eye and runs straight back. Superior Rectus: Eye looks up. Attaches directly to the top of the eye and runs straight back. Medial Rectus: Rotates eye medially or in towards the nose. Attaches directly to the side of the eye and runs straight back. Inferior Rectus: Eye looks down. Attaches directly to bottom of the eye and runs straight back. Inferior Oblique: Eye rolls, looks up and to the side. Attaches along the lateral side of the eye and runs under the eye passing over the inferior rectus and attaches medially. Superior Oblique: Eye rolls, looks down and to the side. Attaches under the superior rectus, passes through a bony spur known as the Trochlea, and then follow the path of the superior rectus. The raised attachment point provides the muscle the ability to give the eye rotation.
Refractive Errors The Emmetropic Eye: Notice that in the emmetropic eye all the rays of light entering the eye all focus on the retina right where they need to be to provide crisp sight without the need of corrective lenses. The Eight Common Refractive Errors of the Human Eye Presbyopia: Presbyopia makes us unable to read fine print, thread a needle, or do fine work without the aid of magnification. Presbyopia is when the crystalline lens can no longer change shape and provide accommodation. It remains in the flatter less plus shape shown in blue. Prescriptions for presbyopia will show corrections for distance, if required, and the additional notation of an add power as in one of these examples: Add +2. Add +1.
Simple Myopia: Simple because all the rays of light entering the eye focus at the same spot, it is the wrong spot, but they all meet at the same place. The retina is further back from the cornea than in an emmetropic eye, so the rays fail to reach the back of the eye and the retina. Persons with myopia are nearsighted; they are capable of seeing things at "near" distances, or up very close to their eyes. They can read fine print, thread a needle, and work with tiny objects. They cannot see a street sign down the road or a bird high in a tree, without correction. Myopia is corrected with minus lenses. It is easy to remember: Just think my-opia and mi-nus lenses. A prescription for a person with simple myopia would be written like one of these examples: -1.00 Sphere -2.50 Sphere Simple Hyperopia: In simple hyperopia all the rays of light entering the eye focus at the same spot, it is the wrong spot, but they all meet at the same place. The retina is further forward toward than the cornea in an emmetropic eye, so the rays are trying to focus on an imaginary point beyond the back of the eye. Persons with simple hyperopia are farsighted; they are capable of seeing things in the distance or far off. They can easily see a street sign half a mile down the road and a bird high up in a tree. They cannot see fine print, thread a needle, or do detail work without correction. Hyperopia is corrected using plus lenses. A prescription for a person with simple hyperopia would be written like one of these examples: +1.00 Sphere +2.50 Sphere
Compound Myopic Astigmatism: This condition is no longer simple, because the rays of light entering the eye do not all meet at the same place. They all fall short of their intended spot on the retina, but some fall closer than others. Depending on the degree of astigmatism (the degree to which the cornea is misshapen) the individual may see objects as bent or distorted in shape as well as blurred. A prescription for a person with a compound myopic astigmatism would look like one of these examples: -1.00 -0.50 X 45 -1.50 +0.50 X 135 -2.50 -2.00 X 130 -4.50 + 2.00 X 45 Compound Hyperopic Astigmatism: This condition is no longer simple, because not all the rays of light entering the eye meet at the same place. They all focus on a spot beyond the retina, but some come closer to the fovea than others. Depending on the degree of astigmatism (the degree to which the cornea is misshapen) the individual may see objects as bent or distorted in shape as well as blurred. A prescription for a person with a compound hyperopic astigmatism would look like one of these examples: +1.00 -0.50 X 45 +0.50 +0.50 X 135 +2.50 -2.00 X 130 +0.50 +2.00 X 40
Mixed Astigmatism: In the eye with mixed astigmatism some rays fall ahead of the retina while others try to focus on a spot beyond the retina. People with mixed astigmatism are neither nearsighted nor farsighted, but instead will have poor vision in all areas. A prescription for a person with a mixed astigmatism would look like one of these examples: +1.00 -2.00 X 45 -1.00 +2.00 X 135 +2.00 -2.25 X 67 -0.25 + 2.25 X 157 Can you match the name with the correct image?
A B C
Simple myopic astigmatism Mixed astigmatism Compound hyperopic astigmatism
The change of speed and direction is why objects appear out of place like the spoon in the glass. The Index of Refraction “n” "n" is the notation for index of refraction. The index of refraction tells us how much a given material will slow down and change the direction of a ray of light passing through it. The higher the index or "n" the thinner a lens can be and produce the same power. Common index numbers include, 1.498, 1.523, 1.586, 1.60, 1.67, and 1.74. It is a scientific absolute that the higher the index of refraction, the thinner a lens can be and still produce the same diopter value. A lens with an index of refraction of 1.74 and a power of – 6.00 will be thinner than a lens with an index of refraction of 1.53 with the same power of – 6.00. Diopter/Prism Diopter The numbers (2.25, 1.25, 0.50) you see on the prescription example represent diopters. Diopters are a unit of measure not unlike an inch, pound, or mile. Technically a diopter is a way of expressing where the rays of light that are passing through a lens (two prisms) will fall. The formula for a diopter is this: D = 1/f When D is diopter, and f is the focal length of a lens in meters. So if I know that a lens has a focal length of 0.50 meters 1/0.50 = 2 My lens diopter power is 2. The formula can also work the other way so that f is equal to 1/D F = 1/D So if I know that a lens is 2.00 diopters 1/2.00 = 0.50 My lens focal length will be 0.50 or half a meter.
Prism diopter: A prism of 1.00D produces the appearance of a 1 centimeter shift in position of an object being viewed at a distance of 1 meter.
It’s Jeopardy Time! Answer the following-
186,000 Miles per second
D = 1/f
400 to 700
A What is the formula for
diopter?
B What is the speed of light?
C What is the range of visible
light in nanometers?
D What is an example of an
index of refraction?
Lenses as Prisms At their heart, all ophthalmic lenses are two prisms, stacked either apex to apex, or base to base. A plus lens is simply two prisms, stacked base to base (the flat bottom of a prism). A minus lens is simply two prisms, stacked apex to apex (the pointy top of a prism). The term used for modern optical lenses is, meniscus lens , because its shape is like the shape of a meniscus moon. A= Exaggerated two prisms stacked apex to apex B = Two prisms stacked apex to apex C = Two prisms stacked apex to apex with a front base curve D = A complete meniscus ophthalmic lens with front base curve and corrected back curve A= Exaggerated two prisms stacked base to base B = Two prisms stacked base to base C = Two prisms stacked base to base with a front base curve D = A complete meniscus ophthalmic lens with front base curve and corrected back curve
