CO Study Guide 2026
Everything you need to pass the CO exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
CO exam key facts
- The AOC Certified Orthoptist recertification fee is currently $175, and applications received after the deadline pay an extra $75 late fee. Source
- International applicants who fail the AOC Certified Orthoptist board exam are strongly advised to enroll in a formal US-based orthoptic training program before trying again. Source
- The AOC Certified Orthoptist credential runs on a three-year recertification cycle, except that the first cycle after certification is two years. Source
📋 CO Exam Format at a Glance
📚 CO Topics to Study (29)
✍️ Sample CO Questions & Answers
1. When using a prism bar to measure a horizontal deviation, the prism base direction should be oriented in which direction to neutralize an esotropia?
Base-out prisms neutralize esotropia by shifting the image toward the deviated eye, allowing the cover-uncover test to show neutralization.
2. An orthotist's certification lapses, but they continue to practice and bill using their expired credentials. This constitutes:
Practicing with lapsed credentials and misrepresenting certification status is fraudulent and a serious ethical and legal violation.
3. When performing a cover-uncover test on a child, a refixation movement of the uncovered eye indicates which condition?
If the uncovered eye moves to take up fixation when the other eye is covered, a manifest tropia (heterotropia) is present in that eye.
4. The AAPOS guidelines recommend that vision screening in children should begin at which age?
AAPOS and AAP guidelines recommend that all children have a vision screening at age 3 years, when cooperation allows photo-screening or acuity testing.
5. The Bagolini striated lens test is used to evaluate which aspect of binocular vision?
Bagolini striated lenses test retinal correspondence and suppression under near-natural viewing conditions by creating streak images from a point source.
6. When is it ethically permissible to share a patient's protected health information with their employer?
PHI can only be disclosed to employers when the patient has specifically authorized that release in writing.
🎯 Free CO Practice Tests
📖 CO Guides & Articles
What Practice Test Geeks adds beyond an AI chat for CO
An AI chatbot can quiz you, but it can't reproduce the exam conditions or keep your record. Here you get:
- A timed, full-length CO mock exam — 100 questions in 180 minutes with a 70% pass mark, modeled on the official exam's question count and time limit, followed by a score report broken down by exam domain.
- A fixed CO question bank: the same test every attempt, so your score is comparable from one try to the next instead of changing with every regenerated quiz.
- Progress saved on your device: completed tests, scores and missed questions stay in My Progress, so you can retake only what you got wrong.
- A printable CO cheat sheet you can print or save as a PDF.
- CO flashcards built from the same question bank.
- Free CO practice tests with the correct answer shown after each question.
How this page was made: written with AI tools and published by Nathan Beja, founder of Practice Test Geeks, who is responsible for its content. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy
Sources & references
Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy
- pearsonvue.com — Eligibility, test dates · verified Oct 2026
- americanorthopticcouncil.org — Test delivery, score validity, eligibility, retake policy, fees, late registration, registration deadline, renewal, exam information · verified Oct 2026