Contact Lenses
121 lenses
Quickly search and sort lenses by brand, replacement, oxygen permeability (Dk), and more.
All 121 lenses →Contact LensesMedicationsGlossarySchoolsHandoutsCalculators
121 lenses
Quickly search and sort lenses by brand, replacement, oxygen permeability (Dk), and more.
All 121 lenses →237 medications
All the information you need to confidently prescribe drops and drugs for ocular disease treatment.
All 237 medications →238 terms
From aberrant regeneration to zylonite, find concise definitions of ophthalmic terms and optical concepts.
All 238 terms →Resection is a strabismus operation that strengthens a rectus muscle by shortening it, which enhances the muscle's effective pull. The procedure is suitable only for a rectus muscle.1
5 calculators
Each calculator has its own page you can bookmark. Every result shows its work.
All 5 calculators →Try it · Back vertex power
More calculatorsToric over-refractionDiopters ↔ radiusTranspositionHydroxychloroquine
9 PDFs
Everything from Amsler grids for your patients to clinical guides and tables to use in your practice.
All handouts →Explains why glasses with a near add come first for convergence excess, which vision therapy exercises are used, and how strong the evidence is.
1,816 questions
Timed practice exams with worked explanations and a score breakdown by topic. The first half of Exam 1 is free.
Open exam prep →EyeKnow O.D. Pro adds 3 more full-length exams and custom drills from all 1,816 questions. $179 for 12 months, intro price to March 18, 2027. See Pro plans →
Question of the day · free, no account
*EyeKnow O.D. is an independent study tool. It is not affiliated with, endorsed by, or sponsored by the National Board of Examiners in Optometry (NBEO®). “NBEO” is used here only to indicate exam coverage.
27 programs
Admissions, cost, board pass rates and campus life for every accredited OD program, side by side.
Compare all 27 →Bayamón, PR · first class 1981