Part I ABS®


Applied Basic Science

The Part I ABS Applied Basic Science examination tests the underlying basic science concepts necessary to enter the clinical practice of optometry.

The Part I ABS examination consists of 350 scored items and 20 non-scored pre-test items. Candidates will not know which items are scored and which are pre-test. The exam is two sessions in length, each session consisting of 185 items. Candidates will have 4 hours to complete each session. The morning session includes an additional 15 minutes devoted to a tutorial and the reading and signing of a non-disclosure agreement (NDA). There is an optional break of up to 45 minutes between the morning and afternoon sessions.

Student candidates must be in the spring of their third academic year to take the Part I ABS exam. There will be three opportunities to sit for the exam prior to graduation.

Most items on the Part I ABS exam require candidates to choose the single best or correct answer. Approximately 10-15% of the items on the exam are multiple-response (MR) items; with MR items the required number of responses (2, 3, or 4) is indicated after the item stem. MR items are scored as completely correct or incorrect; there is no partial credit.



On the Part I ABS examination, drugs are referenced only by generic name. However, to help those candidates who may be more familiar with the trade names of some drugs than the generic names, a list of generic drugs and their trade name equivalents will be available as a searchable PDF. Candidates can see a sample drug list used on a past the Part I ABS exam by clicking on the Drug List link at the bottom of the page. It is important that candidates note that the sample drug list is not intended to be a study guide, nor is it a complete list of drugs that may appear on the exam. Candidates should also be aware that the drug list will include only those drugs that have commonly used trade names. Drugs such as tetracycline or homatropine will not appear on the list. Trade names are sometimes used on the Part I ABS exam when referring to preservatives since some preservatives cannot be identified by a single generic ingredient.

Candidates should note that the non-possessive form will be used on the Part I ABS exam for eponymous terms (e.g., Horner syndrome will be used rather than Horner's syndrome, and Descemet membrane will be used rather than Descemet's membrane). This usage is in accordance with the growing trend in medical and scientific writing to remove the possessive when using eponyms.

A tutorial for the Part I ABS exam can be found on the “Helpful Links” tab. Candidates are strongly encouraged to go through the tutorial prior to exam day so that they can become familiar with the mechanics of taking the exam by computer. Candidates will only have 10 minutes to go through the tutorial on the morning of the exam, and candidates may have difficulty completing the tutorial in that amount of time. Note that the tutorial requires a Windows-based PC and is not available for Mac platforms.

The tutorial includes a short (4-item) sample test. Candidates should be aware that the layout of items on the sample test for the downloadable tutorial is somewhat different than the layout that will be used on the actual exam. On the actual exam, the items will be approximately centered on the screen; on the tutorial, the items are left-aligned. This difference is necessary to allow candidates to view the items on the tutorial regardless of the screen size or resolution they may be using. There are also some minor differences between the downloadable tutorial and the actual exam regarding how the drug list and the calculator can be adjusted on the screen, as well as some minor differences in the appearance of the strikethrough and highlight buttons.

Links to the Part I ABS Content Matrix and the Part I ABS Content Outlines can be found in the “Helpful Links” tab.

The registration fee for the Part I ABS is $950.