ABO Help [Archive] - OptiBoard Discussion Forums

Darryl Meister

10-31-2006, 05:46 PM

If you purchase yourself a decent study guide, and truly take the time to review and learn the materials, you should have no trouble passing the ABO Exam. It is not a difficult test, but it does require you to know the basics of dispensing. There are very few formulas, and very little ocular anatomy. I would recommend learning at least the following topics:

Basic prescription analysis - including the major Rx components, how they are written, and possible errors
Major vision conditions - including the basic refractive errors, anisometropia, aniseikonia, presybopia, aphakia, and binocular vision anomalies, as well as a very basic understanding of major pathological conditions (diabetic retinopathy, glaucoma, and macular degeneration)
Gross anatomy of the eye - again, just the basics, including the major functions of the cornea, crystalline lens, and retina
Managing vertical imbalance - including the definition of vertical imbalance, options to relieve it, and understanding slab-off prism
Prism splitting
Flat transposition - converting from plus to minus cylinder form and back
Toric transposition - calculating back curves given the front curve and prescription (Prescription = Front curve + Back curve)
Physical and optical characteristics of Plus lenses - magnify, produce "against the motion," thicker at the center, produce a real focus, used for hyperopes or presbyopes, etc.
Physical and optical characteristics of Minus lenses - minify, produce "with the motion," thinner at the center, produce a virtual focus, used for myopes, etc.
Physical and optical characteristics of Cylinder lenses - produce "scissors motion," vary in thickness, vary in power from zero in Axis meridian to maximum 90 degrees away, used for astigmats, etc.
Physical and optical characteristics of Prisms - thicker at the base, displace images toward the apex, used to relieve muscle imbalance, etc.
ANSI tolerances - including Sphere Power, Cylinder Power, Cylinder Axis, Add power, Vertical Prism imbalance, and Horizontal Prism imbalance tolerances
Use of the PD ruler - including measurement of Distance PD, Near PD, and segment heights (for bifocal, trifocal, and progressive lenses)
Use of Corneal Reflex Pupillometer to measure PD
Use of distometer to measure vertex distance
Effects of vertex distance on lens power - Plus lenses increase power with greater vertex distance and Minus lenses reduce power
Common adjustment tools - including the major pliers, files, and so on
Use of tools to perform basic adjustments to correct misalignment, maintain correct "fitting triangle," and change panto/retro tilt
Basic frame types - including plastic (optyl, proprionate, zyl, polyamide, etc.), metal (titanium, aluminum, monel, nickel silver, etc.), rimless (nylon, three-piece, notched, etc.), combination, sport, half-eye, ptosis, and moisture chamber
Major components of a frame - including the eyewire, bridge (saddle, adjustable, keyhole, etc.), endpiece, pad/guard arm (screw, bayonet, push, clamp, etc.), temple (skull, library, riding bow, cable), and earpiece
Converting from metric to imperial (inches) temple lengths - 145 mm = 5 3/4"
Boxing system of frame measurement - including A, B, DBL, and ED
Basic lens types - including single vision, bifocal, trifocal, progressive, and occupational lenses
Basic high-powered lens types - including aspheric lenticulars, myodiscs, Fresnel press-on optics
Basic lens materials and their properties (index, Abbe, impact resistance, density, etc.) - including Glass, Hard Resin, Polycarbonate, and High-index
Basic lens treatments - including PhotoGray, Transitions, polarized, tint types & visual benefits, UV treatment, and antireflection coating
Use of the lens clock (or lens measure) to measure surface power
Basic lensometry - including its use to measure power, prism, and Add power, as well as the major components of popular lensometers
Basics of lens thickness - including the effects of prescription, blank size, refractive index, and methods to reduce thickness (minimizing decentration, rolling edges, etc.)
Basics of lens design and base curve theory to maintain good peripheral optics
Major regulations pertaining to lenses - FDA's impact resistance guidelines (including drop ball test specifics), OSHA's Z87.1 guidelines, FTC's prescription release guidelines, and so on
Calculation of decentration: (Frame A + Frame B - Wearer PD) / 2
Calculation of minimum blank size: 2 * Decentration + Frame ED
Calculation of prism: Decentration / 10 * Power
Calculation of focal length: 1 / PowerA big part of the ABO is simply recognizing terms, such as frame components, vision defects, or specialty lens types. Another part is the applications of certain terms. For instance, a "slab-off" lens corrects "vertical imbalance," an "iseikonic" lens corrects "aniseikonia," etcetera. A second part is applying basic problem-solving skills. For instance, if the left side of the wearer's frame is too low, you would angle the left temple down or the right temple up to fix it. A third part is understanding the very basic principles of optics.

Also, you probably won't have to calculate vertex distance compensation, but you will need to know that a weaker Plus lens should be ordered if the fitted vertex distance is larger than the refracted vertex distance, and vice versa. Standards and regulations will be another important part, though I don't know if the ABO is using the most current version of the Z80.1 (2005) Standard (http://www.opticampus.com/tools/ansi.php). There may also be a question on HIPAA compliance.

Additionally, there are some general test-taking tips to remember. First and foremost, be prepared. Don't wait until the day before the test to pick up your study materials. Learn the materials until you are confident that you understand the principles. When taking the actual test, first read each question carefully, and then read each answer carefully before picking one. If you don't know the answer, note your spot and move on to the next question. You definitely don't want to get stuck on a single question, and sometimes a future question may even provide the answer for you.

Once you have gone through the test, you may go back through your unanswered questions, eliminating possibilities and finally guessing if you need to from the remaining possibilities (be sure to mark something though). Common sense goes a long way on the ABO exam. Also, if a question seems subjective or ambiguous or you don't agree with any of the answers, tell them what you think they want to hear. And be careful when second-guessing yourself.

Finally, get enough sleep, eat a good breakfast, bring enough pencils, keep your test anxiety low, and remember all those other test-taking tips they talked about in school.

I also recommend the National Academy of Opticianry's Ophthalmic Dispensing Review Book (http://www.nao.org/catalog/iteminfo.cfm?itemid=276&compid=1), which is an extensive multiple-choice question & answer guide for preparing for the ABO exam.