CO Practice Test

The Certified Orthoptist (CO) credential is earned by passing a written and oral board certification exam from the American Orthoptic Council after 24 months of training in an AOC-accredited program. This page gives you free practice sets grouped by topic and worked explanations for sample questions. It also gives a short summary of the verified rules on eligibility, test timing and recertification, so you know what to confirm with the official body.

CO Exam at a Glance

What changed for CO in 2026

• Dec 1, 2025: The American Orthoptic Council issued an updated Continuing Education Handbook for Certified Orthoptist recertification, effective December 1, 2025.^[1]

What the CO is and how it works

According to American Orthoptic Council, “After satisfactorily completing 24 months of orthoptic training in an AOC accredited program, and upon the recommendation of the supervising orthoptists with whom they have trained, students are eligible to sit for the American Orthoptic Council certifying examinations.”^[5]

The CO credential is awarded by the American Orthoptic Council (AOC). After you finish your orthoptic program, you take a written exam and an oral board certification exam, both given by the AOC.

Who can sit for it

You must satisfactorily complete 24 months of orthoptic training in an AOC-accredited program. You also need a recommendation from the supervising orthoptists you trained with. International applicants must pass the online European Diploma for Orthoptists exam, show English at CEFR B2 or above, and document formal orthoptic training. If an international applicant does not pass the AOC board exam, the AOC strongly recommends enrolling in a US-based orthoptic training program before attempting a second time.

When and where

The written exam is held during the third week in June at Pearson VUE test centers. A Pearson VUE agent helps you find a center. We could not verify the exam fee, the scoring method or the passing standard, so check the American Orthoptic Council website and ask your program director for current details.

After you pass

Certification runs on a 3-year recertification cycle, and each cycle needs 45 CE credits. Newly certified orthoptists recertify after their first 2 years, when 30 credits are due. Forms are due November 20 each year. The fee is $175, and a $75 late fee applies to applications received after the deadline.

Worked examples: how to reason through CO questions

These are practice questions written for this site, not questions from the real exam. Each explanation shows why the right answer is right and why the others are wrong.

Example 1

Question: What role do standard operating procedures play in CO Infection Control & Prevention?

1. Ensuring consistency and quality through documented instructions
2. Restricting creativity
3. Creating unnecessary paperwork
4. Satisfying management only

Answer: A. Ensuring consistency and quality through documented instructions

Explanation:

A is correct. A standard operating procedure (SOP) is a written, step-by-step instruction for a task such as cleaning an occluder, disinfecting a prism bar or handling a patient with conjunctivitis. Because everyone follows the same documented steps, the result is consistent no matter which qualified staff member does the work. That consistency is what prevents infection from spreading between patients.

B is wrong because SOPs limit unsafe variation, not professional judgment. C is wrong because the documentation has a purpose: training, auditing and accountability. D is wrong because SOPs exist to protect patients and staff, not just to satisfy managers.

Rule to remember: in infection control, SOPs mean the same safe steps every time, by every person.

Example 2

Question: Which visual field defect is typically associated with a lesion in the left occipital lobe?

1. Bitemporal hemianopia
2. Right homonymous hemianopia
3. Left homonymous hemianopia
4. Quadrantanopia

Answer: B. Right homonymous hemianopia

Explanation:

B is correct. Behind the chiasm, each side of the brain handles the opposite half of the visual field for both eyes. The left occipital lobe receives input about the right visual field from both eyes. So a lesion there causes a right homonymous hemianopia: the same right-sided field loss in each eye.

A is wrong because bitemporal hemianopia comes from damage at the optic chiasm, often from a pituitary lesion, not from the occipital lobe. C is wrong because it is on the same side as the lesion. A left homonymous defect points to a right-sided lesion. D is wrong because a quadrantanopia usually reflects partial damage to the optic radiations in the temporal or parietal lobe. It does not match the full hemifield loss described here.

Rule to remember: lesions behind the chiasm cause homonymous defects on the opposite side.

Example 3

Question: The Worth 4-Dot test primarily assesses:

1. Stereoacuity in arc seconds
2. Binocular sensory fusion and suppression
3. Contrast sensitivity
4. Color vision deficiency

Answer: B. Binocular sensory fusion and suppression

Explanation:

B is correct. In the Worth 4-Dot test, the patient wears red-green glasses, so each eye sees only some of the lights. What the patient reports shows whether the eyes fuse the images, whether one eye is suppressed, or whether there is diplopia. Testing at distance and at near shows how fusion changes with target size and position.

A is wrong because stereoacuity is measured with stereo tests such as Titmus or Randot, not with a flat light target. C is wrong because contrast sensitivity uses charts such as Pelli-Robson. D is wrong because, although the test uses coloured filters, it does not grade colour vision. Plates such as Ishihara are used for that.

Rule to remember: the Worth 4-Dot test checks sensory fusion and suppression, not depth perception.

How to use these practice tests

Use the practice sets to find your weak areas. Then go back to your training material and the official AOC information to fix them.

1. Take a baseline set. Start with Ocular Motility Evaluation & Binocular Vision Assessment and Diagnosis & Management of Strabismus and Amblyopia, because motility and binocular vision are at the core of orthoptic work. Mark every question you missed or guessed.
2. Work through the clinical topics. Move on to Neuro-Ophthalmic Disorders, Pediatric Vision Development & Screening and Anatomy & Physiology of the Visual System. For each miss, write the general rule in your own words, as the worked examples above do.
3. Cover the practice-side topics. Finish with the ethics, documentation, infection control, patient safety and pharmacology sets.
4. Practise out loud. Because there is also an oral exam, explain your reasoning for a case aloud or to a classmate instead of only picking an answer.
5. Check the logistics. Confirm with your program director and the AOC when your recommendation is submitted. Then contact Pearson VUE to book a center for the third week in June.

Sources & last verified

1. American Orthoptic Council — exam fee, renewal, registration deadline, late registration deadline (official source). “The fee is currently $175, and a late fee of $75 is applied for applications received after deadline.” Verified Oct 21, 2026.
2. American Orthoptic Council — retake policy, eligibility (official source). “However, if the applicant is unsuccessful in passing the AOC® board examination, the AOC® strongly recommends enrolling in a formal US-based orthoptic training program before…” Verified Oct 21, 2026.
3. American Orthoptic Council — validity (official source). “The AOC® requires orthoptists to submit their continuing education credits every three years, except for newly certified orthoptists, who will recertify after the first two…” Verified Oct 21, 2026.
4. American Orthoptic Council — delivery (official source). “Once you have completed your orthoptic program, you will take a written and oral board certification exam given by the American Orthoptic Council®.” Verified Oct 21, 2026.
5. pearsonvue.com — eligibility, testing window (official source). “After satisfactorily completing 24 months of orthoptic training in an AOC accredited program, and upon the recommendation of the supervising orthoptists with whom they have…” Verified Oct 21, 2026.

How we verify: editorial & fact-checking policy. Report an error: contact us.