Spectral-domain optical coherence tomography (SD-OCT) is a key tool in the diagnosis and evaluation of glaucoma. On OCT printouts, measurements of the retinal nerve fiber layer (RNFL), macula, and optic nerve are compared to a normative database of age-matched normals and then color-coded. A color-coding of green (“within normal limits”) suggests that the patient is normal and has nerve tissue values similar to age-matched normals. Yellow (“borderline”) is a warning and suggests that the patient’s values may be slightly thinner than normal. Red (“outside normal limits”) indicates that the patient has glaucoma and has very thin nerve tissue.
