Loading...
Loading...
ABO and COA both involve eyes. Both require certification exams. Both can lead to solid careers in eye care. And that is about where the similarities end.
These two credentials represent entirely different professions within the eye care industry. An ABO-certified optician works with eyewear -- fitting frames, interpreting prescriptions, selecting lenses, and making adjustments. A COA-certified ophthalmic assistant works with patients in a clinical setting -- measuring intraocular pressure, running visual field tests, taking retinal images, and assisting with surgical procedures.
The confusion is understandable. From the outside, "someone who works in an eye doctor's office" describes both roles. But from the inside, you would not hire an optician to run a visual field test, and you would not ask an ophthalmic assistant to adjust a pair of progressives. The skill sets are distinct, the certifying bodies are separate, and the career ladders do not intersect.
If you are trying to decide which path to pursue -- or if someone told you to "get certified" and you are not sure which exam they mean -- this comparison lays out everything you need to choose correctly.
| ABO | COA | |
|---|---|---|
| Full Name | American Board of Opticianry | Certified Ophthalmic Assistant |
| You Are A... | Optician | Ophthalmic Assistant |
| Certifying Body | ABO-NCLE | IJCAHPO |
| Exam Name | NOCE | COA Exam |
| Questions | 125 | 200 |
| Time | 2 hours | 3 hours |
| Cost | $225 | $300 |
| Core Focus | Eyewear dispensing & fitting | Clinical diagnostic testing |
| Work Setting | Optical shops, dispensaries, retail | Ophthalmology clinics, hospitals |
| You Work With | Frames, lenses, prescriptions | Patients, instruments, imaging |
| Advancement | ABO Advanced → Master | COA → COT → COMT |
| Average Salary | ~$59k (~$83k licensed) | ~$63-68k |
| State Licensure | 22 states require it | Not required |
This is the most important difference, and it is not subtle. These two roles share an industry but almost nothing else about the daily work.
The Simplest Way to Think About It
An optician works with products (lenses, frames, coatings). An ophthalmic assistant works with patients (clinical tests, diagnostic procedures, surgical prep). Both are essential to eye care, but they sit on opposite sides of the practice. One is retail and technical; the other is clinical and medical.
The tools you use every day tell the story. An optician's workbench has a lensometer, a pupillometer, frame adjustment pliers, and a heating unit. An ophthalmic assistant's workstation has a slit lamp, a tonometer, a visual field analyzer, and an OCT machine. There is essentially no overlap in the equipment you would be trained on.
The exams reflect this divide. The ABO (NOCE) tests your ability to calculate lens powers, select appropriate frame materials, measure pupillary distance, and verify prescriptions. The COA exam tests your ability to measure eye pressure, assess pupillary responses, document patient histories, and operate diagnostic imaging equipment. Studying for one does almost nothing to prepare you for the other.
There is one scenario where both credentials intersect: a comprehensive ophthalmology practice that has its own optical dispensary in-house. The clinical side hires COAs to run pre-testing. The optical side hires ABO-certified opticians to fill prescriptions. They share a building and a patient population but perform completely different functions.
State Licensure for Opticians
22 states currently require opticians to be licensed. In those states, passing the ABO exam (NOCE) is typically part of the licensing requirement. If you live in one of these states and want to dispense eyewear, the ABO is not optional -- it is legally required. Ophthalmic assistants (COA holders) have no state licensure requirement anywhere in the U.S.
COA holders have a slight edge in base salary, averaging around $63,000-$68,000 compared to roughly $59,000 for ABO-certified opticians. But the optician track has a wild card: state licensure. Licensed opticians in states that mandate licensing earn significantly more -- around $83,000 on average. If you live in one of those 22 states, the ABO path can actually out-earn the COA path.
Both tracks offer clear advancement potential. ABO-certified opticians can pursue the Advanced and Master ABO certifications, or add the NCLE for contact lens specialization. COA holders can advance to COT and then COMT, with each level bringing expanded clinical responsibilities and higher compensation.
Opterio has adaptive practice questions for both ABO and COA exams. AI-powered explanations help you learn as you go.
Study tips, exam format, and practice questions for optician certification.
Everything about the COA exam: format, domains, eligibility, and cost.
The complete map: ABO, NCLE, COA, CPO, CPOA, and more.
Explore all career paths in the eye care industry.
ABO (American Board of Opticianry) certifies opticians who dispense and fit eyeglasses. COA (Certified Ophthalmic Assistant) certifies clinical personnel who perform diagnostic tests in ophthalmology. An optician hands you your new glasses and adjusts them. An ophthalmic assistant measures your eye pressure, runs visual field tests, and preps you for the doctor. Same industry, completely different jobs.
Not in a clinical role. An ABO certifies your competency in dispensing, not clinical testing. An ophthalmology clinic hiring for a clinical assistant position will look for a COA (or someone willing to earn one). However, if the same clinic has an in-house optical dispensary, an ABO-certified optician would work on that side. The two roles rarely overlap in practice.
COA holders generally earn slightly more on average -- roughly $63,000 to $68,000 versus about $59,000 for ABO-certified opticians. However, licensed opticians in states that require licensure can earn significantly more, averaging around $83,000. Geography, employer type, and years of experience all affect these numbers substantially.
Neither requires a college degree. Both require a high school diploma or equivalent. The ABO exam has no formal experience requirement, though hands-on training is strongly recommended. The COA has specific eligibility pathways that require supervised clinical hours in an ophthalmology setting (0 to 1,000 hours depending on your educational background).
Yes. They are administered by completely separate organizations (ABO-NCLE and IJCAHPO). This would make sense if you work in a comprehensive ophthalmology practice with both a clinical side and an in-house dispensary. But it is uncommon because the career paths diverge significantly -- most people specialize in one or the other.
They test entirely different knowledge, so comparing difficulty head-to-head is not straightforward. The COA is a larger exam (200 questions in 3 hours vs. 125 in 2 hours for the ABO) and covers a broader range of clinical skills. The ABO exam includes optical math and lens calculations that many people find challenging. Both require dedicated preparation, but the material barely overlaps.