This guideline covers diagnosing and managing glaucoma in people aged 18 and over. It includes recommendations on testing and referral (case-finding) for chronic open-angle glaucoma and ocular hypertension and on effective diagnosis, treatment and reassessment to stop these conditions progressing. We have produced a large print version of this guideline, which is available to download in tools and resources. In January 2022, we reviewed the evidence and updated the recommendations on treatment for ocular hypertension and chronic open-angle glaucoma and organisation of care. For more information, see update information.