C/D
Medical abbreviation · Ophthalmology & ENT
| Stands for | Cup-to-disc ratio |
|---|---|
| Categories | Medical |
C/D stands for Cup-to-disc ratio, an ophthalmology & ENT abbreviation.
Ratio of the diameter of the central pale cup of the optic nerve head to the diameter of the whole disc, used to assess glaucoma. Normal ratios are typically around 0.3, and larger values or asymmetry between eyes raise suspicion of glaucomatous damage.
Example: C/D 0.7 OD, 0.4 OS; glaucoma suspect, obtain OCT RNFL and visual fields.
Usage notes
Often recorded as the vertical ratio. A difference of more than 0.2 between the two eyes is a warning sign. Large discs naturally have larger cups, so the ratio is interpreted together with disc size, nerve fiber layer imaging and visual fields. Also written CDR.
Related abbreviations
More ophthalmology & ENT abbreviations
- AREDS – Age-Related Eye Disease Study
- ARMD – Age-related macular degeneration
- BCVA – Best-corrected visual acuity
- BOM – Bilateral otitis media
- BPPV – Benign paroxysmal positional vertigo
- BRVO – Branch retinal vein occlusion
- CF – Counting fingers
- CHL – Conductive hearing loss
- CI – Cochlear implant
- CRAO – Central retinal artery occlusion
- CRS – Chronic rhinosinusitis
- CRVO – Central retinal vein occlusion
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This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.