What does choroidal mean?
Choroidal is a technical adjective of anatomy and medicine meaning 'of or relating to the choroid' — the darkly pigmented, richly vascularized layer sandwiched between the retina and the white sclera at the back of the eye. The choroid supplies oxygen and nutrients to the outer layers of the retina, so when clinicians describe choroidal circulation, choroidal thickness, or choroidal neovascularization, they are talking about the health and behaviour of this vital blood-vessel network. The word surfaces most often in ophthalmology: conditions such as wet age-related macular degeneration involve abnormal choroidal vessels invading the retina, and choroidal melanoma is the most common primary cancer inside the adult eye. Because it belongs to specialist register, choroidal rarely appears outside clinical, research, or science-journalism contexts, where it lends precision to descriptions of eye structure and disease.
adjectiveRelating to or affecting the choroid, the pigmented vascular layer of the eye lying between the retina and the sclera.
- Relating to or affecting the choroid, the vascular layer of the eye between the retina and the sclera.
"The scan revealed early signs of choroidal thinning in her left eye."
"Wet macular degeneration is driven by abnormal choroidal blood vessels growing beneath the retina."
"Ocular ultrasound can help distinguish a choroidal nevus from a melanoma."
Every drop of blood feeding your light-sensitive retina passes through the choroid — which is why ophthalmologists watch 'choroidal' changes so closely as you age.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of choroidal
Choroidal derives from choroid, an adjective-turned-noun borrowed in the seventeenth century from Greek khorioeidēs, literally 'membrane-like', formed from khórion (a variant of khorion, the outer embryonic membrane) combined with eîdos ('form, likeness'). Greek anatomists applied the term to the delicate vascular coat of the eye because of its membrane-like appearance. English formed the adjective choroidal directly from choroid with the suffix -al, following the pattern of learned anatomical terminology shared across European languages.
How choroidal is actually used
Strictly a technical medical term, used almost exclusively in ophthalmology, optometry, and anatomy. It appears in clinical writing and patient-facing health material rather than everyday conversation, and carries no figurative or informal use.
Easily confused with choroidal
Choroid is the noun naming the vascular layer of the eye itself, while choroidal is its adjectival form used to modify other nouns.
Cortical relates to the cortex (as of the brain or kidney), whereas choroidal refers specifically to the vascular layer of the eye.