NBEO Part I ABS: What the Exam Covers and How to Prepare

Part I Applied Basic Science (ABS®) is the first examination of NBEO's three-part licensure exam series. It assesses the biomedical science concepts essential to safe and effective independent optometry practice, delivered as a one-day computer-based test of 370 items — 350 of them scored. This guide covers the verified format, the 2026 content matrix, eligibility and attempt rules, fees, and a practical way to turn the matrix into a study plan.

What Part I ABS assesses

Part I ABS tests the biomedical science foundations of optometric practice: NBEO describes it as assessing the knowledge, understanding, and application of concepts essential to safe and effective independent practice.

It is the first of three entry-into-the-profession licensure exams, followed by Part II PAM/TMOD and Part III PEPS. Those are separate examinations with their own eligibility timing, so do not plan for them as if they shared Part I's schedule. Part I is delivered on computer at Pearson testing centers in a single day.

One wording note from NBEO: the exam uses the non-possessive form for eponyms. You will see Horner syndrome rather than Horner's syndrome, and Descemet membrane rather than Descemet's membrane.

Sources: Part I ABS® – NBEO — Exam information and Practice Items Databank pages; Part I ABS Content Outline – Condition-Based — 2026 PDF, category totals and condition sections; Exam Policies & Eligibility – NBEO — Exam Eligibility Policy, Six-Time Limit Policy, Withdrawal Policy

Format, timing, and scoring

Expect 370 items in two sessions of 185, four hours per session, an optional 45-minute break between sessions, and a reported score on a scale where anything above 300 passes.

The exam contains 350 scored items plus 20 unscored pre-test items, and you will not know which are which. Each of the two sessions holds 185 items and allows four hours. The first session adds 15 minutes for a tutorial and signing a non-disclosure agreement, and an optional break of up to 45 minutes separates the sessions. Once that break ends, you cannot return to Session 1.

About 10–15% of items are multiple-response: the stem tells you how many answers to choose, either two, three, or four. These are scored as completely correct or incorrect, with no partial credit, so treat each one as an all-or-nothing decision.

An on-screen TI-30XS scientific calculator is available throughout. NBEO notes that all optics items are designed so the correct answer can be determined without trigonometric functions; the calculator is there if you prefer to use them. Drugs are referenced by generic names, and a searchable on-screen list maps generic drugs to common trade names. NBEO explicitly cautions that the sample drug list is not a study guide and is not necessarily complete.

NBEO creates multiple forms of each exam and uses equating to adjust raw scores for difficulty differences between forms, so your result reflects your performance rather than your form. There is no curve and no fixed pass count. Part I ABS scores convert to a scale from 100 to 900, and anything above 300 is a passing score. Score reports typically post about seven weeks after the complete administration, announced on the NBEO homepage.

Sources: Part I ABS® – NBEO — Exam information and Practice Items Databank pages; Part I ABS Test Day Instructions — May 2026 PDF; Scoring & Results – NBEO — Score scaling, equating, and release sections

Eligibility and attempt limits

Student candidates become eligible for Part I ABS beginning with the March administration of their third professional year at an ACOE-accredited program; graduates are eligible directly, and anyone else must be sponsored.

Student candidates can first sit Part I ABS with the March administration during their third professional year, at a program holding Accreditation Council on Optometric Education status of Accredited, Accredited with Conditions, or Preliminary Approval. NBEO must receive confirmation of your year in the program from your institution, so coordinate with your school's authorized NBEO liaison before registering.

Graduates of programs with ACOE Accredited or Accredited with Conditions status are eligible for NBEO examinations. Candidates who are neither current students nor graduates of such programs must be sponsored — by a state licensure board of optometry or an eligible optometric degree program, which sends a letter of sponsorship directly to NBEO.

These are licensure examinations: once you have passed Part I ABS, you cannot simply retake it. A retake requires either a written request from a state licensing board or a signed, notarized affidavit from you stating the retake is needed for licensure purposes, plus an NBEO exception granted under special circumstances.

Plan attempts carefully. Candidates must pass each entry-into-the-profession examination within their first six attempts, and an attempt counts whenever you begin any portion of the exam. Beyond six attempts, you need a remediation plan, a sponsor who is a Chief Academic Officer or Chief Executive Officer of an ACOE-accredited institution, committee approval, and a $300 non-refundable request fee.

Sources: Exam Policies & Eligibility – NBEO — Exam Eligibility Policy, Six-Time Limit Policy, Withdrawal Policy

Fees, late registration, and withdrawals

Part I ABS costs $1,490 for examinations administered beginning August 2026; late registration adds a non-refundable $400, and withdrawal refunds depend on how much notice you give.

NBEO's fee schedule lists Part I ABS at $1,490 for examinations administered beginning August 2026. Registering late costs an additional $400, and that late fee is non-refundable — late registrants are also not guaranteed seat availability at Pearson VUE.

Withdrawal rules scale with notice. Written notice to NBEO 30 or more days before the first testing date earns a full refund. Notice before the withdrawal deadline — 14 days before the first testing date for Part I — earns a refund minus a 20% service fee. After that deadline, the entire fee is forfeited. NBEO may make exceptions for circumstances beyond your control, such as illness or severe weather, if you submit the fee-waiver request form within 15 days of the originally scheduled exam date.

Sources: Exam Fees – NBEO — Rates for examinations administered beginning August 2026; Exam Policies & Eligibility – NBEO — Exam Eligibility Policy, Six-Time Limit Policy, Withdrawal Policy

What the content matrix covers

NBEO describes the same 350 scored items two ways: by 17 condition areas grouped into two categories, and by five science disciplines. Both outlines contain identical topics, sorted differently.

The condition-based outline and the discipline-based outline are not different exams. NBEO states they include identical topics, sorted by either conditions or disciplines. The condition view allocates 122 scored items to Refractive Status / Sensory Processes / Oculomotor Processes and 228 to Normal Health / Disease / Trauma. Items in Emergencies / Trauma are embedded within the other condition areas rather than forming a separate block.

The table below is the compact map. For the full subtopic detail — every listed technique, structure, and drug class — use NBEO's own outlines, which run to dozens of pages.

Use the discipline view as a coverage check on the same items: Anatomy (gross, neuroanatomy, histology, developmental) contributes 12–18% (42–62 items); Biochemistry and Physiology 10–14% (35–49); Immunology, Microbiology and Pathology 22–30% (77–105); Optics — geometrical, physical, ophthalmic, and physiological — 31–35% (108–122), the largest single discipline; and Pharmacology 11–17% (40–60). Treat every figure as a range for one administration, not a cumulative quota; the condition ranges are constrained by their category totals.

Sources: NBEO Part I ABS Content Matrix, April 30, 2026 — Matrix table and item-count note; Part I ABS Content Outline – Condition-Based — 2026 PDF, category totals and condition sections; Part I ABS Content Outline – Discipline-Based — 2026 PDF

Turning the matrix into a study plan

Organize by condition area, use each outline section's own science headings to connect disciplines, and check discipline coverage with the percentages — because both views describe the same 350 items.

If the matrix looks overwhelming at first, the structure is the fix. The two views describe one exam, so you never need to cover them separately. Studying by condition area is efficient because each outline section already names the sciences it draws on: the Glaucoma section, for example, spans gross and developmental anatomy, the physiology of intraocular pressure and aqueous, pathology, and pharmacology. One condition-area pass therefore touches several disciplines at once.

A weekly rhythm you can adapt — this is study advice, not an NBEO requirement: pick two or three condition areas, review their outline subtopics against your class notes, then do timed practice items. The official Practice Items Databank lets you select items by content area, so you can drill the condition you are currently reviewing. Keep a log of missed items by condition area and give the weakest one the first slot of the next week.

Use the discipline percentages as a coverage check rather than a calendar. Optics accounts for roughly a third of scored items and appears across Ametropia, Ophthalmic Optics / Spectacles, Contact Lenses, and Low Vision, so it is spread across several chapters of a condition-based plan rather than sitting in one block. Before your final weeks, verify no condition area — including the small ones like Low Vision — has gone untouched.

The condition-area ranges are bounds within the fixed category totals of 122 and 228 scored items. They do not add another set of questions to the exam, and all minima or all maxima need not occur on the same exam form.

Sources: Part I ABS® – NBEO — Exam information and Practice Items Databank pages; NBEO Part I ABS Content Matrix, April 30, 2026 — Matrix table and item-count note; Part I ABS Content Outline – Condition-Based — 2026 PDF, category totals and condition sections

Test day: arrival, identification, and rules

Arrive 30 minutes early with two valid physical IDs, one government-issued photo ID; arriving more than 15 minutes late may mean denial of admission with no refund.

Check-in includes a digital photograph, a palm vein scan, agreement to the Pearson test-center rules, and a security scan using infrared and metal-detection wands. Anyone found with an unauthorized electronic device will not be permitted to test, may forfeit exam fees, and may face Improper Conduct consequences under the NBEO Ethics Policy.

Go through the exam tutorial on the NBEO website before test day. At the test center you get only 10 minutes for it, which may not be enough time to finish there.

• Arrive 30 minutes before your scheduled appointment. Candidates more than 15 minutes late may be denied admission, with no refund and no rescheduling outside the published testing date.
• Bring two current, signed, physical forms of identification; at least one must be government-issued photo ID, such as a driver's license, passport, or military ID.
• Personal items — bags, phones, watches, notes, even eyewear with camera functionality — stay in provided lockers. Electronic devices are not permitted anywhere in the test center, including restrooms.
• You receive a marker and a scratch-paper booklet. No notes until the first item appears, no notes during the NDA or tutorial, and only one booklet at a time.
• Restroom breaks are allowed, but the exam clock keeps running and you may need to re-verify identity on return. During the scheduled 45-minute break you may access your belongings, including your phone.
• Food and drink are allowed only during breaks; candidates with medical dietary needs should request accommodations through NBEO's accommodations process.
• If something unusual happens, use the 'Critiques' button on the item screen, the post-session comment space, or email NBEO within 72 hours — later emails are not considered.

Sources: Part I ABS Test Day Instructions — May 2026 PDF; Exam Policies & Eligibility – NBEO — Exam Eligibility Policy, Six-Time Limit Policy, Withdrawal Policy

Preparation pitfalls worth avoiding

Check multiple-response scoring, resource limitations and booking deadlines as part of your preparation.

• Assuming partial credit on multiple-response items — there is none; every required response must be correct.
• Studying the sample drug list as if it were complete — NBEO says it is not a study guide and not necessarily a complete list of drugs appearing on the exam.
• Preparing only with the Practice Items Databank — NBEO states completion of its items does not guarantee a passing score and that it should not be your only means of preparation.
• Cutting registration timing close — the $400 late fee is non-refundable and seat availability is not guaranteed.
• Letting the withdrawal deadline pass silently — after 14 days before testing, the full fee is forfeited.

Sources: Part I ABS® – NBEO — Exam information and Practice Items Databank pages; Part I ABS Test Day Instructions — May 2026 PDF; Exam Fees – NBEO — Rates for examinations administered beginning August 2026

Your next steps

Confirm your eligibility window with your institution's NBEO liaison, register early, download the official outlines, and plan review around your weakest condition areas.

• Confirm your third-year eligibility and institution confirmation with your school's authorized NBEO liaison.
• Register early to avoid the $400 late fee, and note the withdrawal deadlines when you book.
• Download the condition-based outline, the discipline-based outline, and the content matrix from optometry.org; mark your weakest condition areas first.
• Build in timed mixed-item practice in your final weeks, using content-area selection in the official databank where useful.
• Review the exam tutorial, the NBEO Ethics Policy, and the Candidate Agreement before test day.

Sources: NBEO Part I ABS Content Matrix, April 30, 2026 — Matrix table and item-count note; Part I ABS Content Outline – Condition-Based — 2026 PDF, category totals and condition sections; Exam Policies & Eligibility – NBEO — Exam Eligibility Policy, Six-Time Limit Policy, Withdrawal Policy

Sources

Facts checked: Sep 13, 2026

• Part I ABS® – NBEO
• NBEO Part I ABS Content Matrix, April 30, 2026
• Part I ABS Content Outline – Condition-Based
• Part I ABS Content Outline – Discipline-Based
• Part I ABS Test Day Instructions
• Exam Policies & Eligibility – NBEO
• Exam Fees – NBEO
• Scoring & Results – NBEO

Next steps

• Free practice items for NBEO Part I ABS
• All optometry exam study guides