- Optical Measurements for ECPs
- Opticalc Contact Lens Calc
- Optician Magazine
- Optics Clinical Calculator
- Vision Training & Eye Exercise
- OptimAbs-Tracker
- Optime UMMS
- Optimization range [Orange]
- Optio Dentistry
- Optio TV
- OptiQuiz Contact Lens
- OptiQuiz Gold
- Optiswiss App
- OptMyCare
- Opto-Screen
- OptoDrum
- OptoFitting
- Optometry Admission Test
- Optomic
- Optonet Vision Unit
- Vision therapy: Exercices
- OptoPrep - NBEO® Part I
- OptoPrep - NBEO® Part II
- OptoView
- OpTranslate
- myDigitalKnee
- OQIC Medical
- OR Tracker Mobile
- Oral Board Study Guide
- Oral Contraceptives
- Oral Diagnosis Cram Cards
- Oral Health Observatory
- Oral Radiology - SecondLook
- Oral Surgery Cram Cards
- Oral-B
- MyOralCare
- MyOralCarePro
- ORALCLOUD
- ORALCLOUD.IN
- Oralien
- ORB Calculator
- ORBE
- Orbit CME – Search & Discover
- Orbit Healthcare
- Orbitology URP App
- ORCA mobi
- オーキドメーター
- Orchyd: Period Tracker & OBGYN
- Ordem dos Médicos Dentistas
- Order-epi HD
- OrderZen
- Orduna e-Learning
- Oremia Mobile - Dentaire
- Organ Clock
- Organ Donation App
- Organ Flights
- Organdonation
- Organic Nomenclature
- Organic Reaction Cards
- 3D内臓(解剖学)