ONH
Optic Nerve Head
Plain-language definition
The visible portion of the optic nerve inside the eye where nerve fibers exit to carry visual signals to the brain. Also called the optic disc.
Expanded explanation
ONH is the glossary term for Optic Nerve Head. On a full article page, it should be read as a anatomy term, not as a stand-alone diagnosis or treatment plan.
When this term appears in an article or clinic note, it is usually naming a structure, layer, space, or location. The important next step is to connect that structure with the symptom, exam finding, image, or disease process being discussed.
In eye care context
Anatomy terms name the eye, orbit, optic nerve, retina, or visual pathway structures that may appear in an exam note or imaging report.
What to look for around this term
- Which part of the eye, orbit, optic nerve, retina, or visual pathway is being described.
- Whether the structure is normal, swollen, thinned, inflamed, scarred, displaced, or damaged.
- Which test or exam finding showed the change, such as OCT, visual field testing, imaging, or the dilated eye exam.
Questions this term may raise
- Which structure is involved?
- Is the finding expected, borderline, or abnormal?
- Does this structure explain the symptoms being discussed?
- Category
- Anatomy
- Also written as
- No alternate forms listed.
Related glossary terms
- afferent
Carrying Signals to the Brain
- aqueous
Eye Fluid (Front Chamber)
- blood-retinal
Protective Eye Barrier
- bulbar
Eyeball-Related (or Brainstem-Related)
- capillaries
Tiny Blood Vessels
- chiasm
Optic Nerve Crossing
A note on medical context
A glossary definition can explain a word, but it cannot tell you whether a symptom or test result is serious. If this term came from an article, use the full article and your clinician's guidance for context.