What is the difference between the optic disc and cup?

The optic disc is usually round or oval in shape and is made up of two main parts: the outer rim and the cup. The outer rim tends to be orange or pink in colour and contains the nerve fibres. The cup (in the centre) is a pit where there are no nerve fibres — this pit is where blood vessels enter the eye.

Is optic disc same as optic nerve?

Optic disc: The circular area in the back of the inside of the eye where the optic nerve connects to the retina. Also called the optic nerve head.

What is the optic cup?

Optic cup: The white, cup-like area in the center of the optic disc. The optic disk is the circular area at the back of the inside of the eye where the optic nerve connects to the retina.

What is optic disc cupping?

Cupped disc. The cupping of the optic nerve means the size of the depression in the middle of the nerve when viewed from the front of the eye. When there is damage to the optic nerve, the cupping increases.

What is cup disc ratio in the eye?

The normal cup to disc ratio (the diameter of the cup divided by the diameter of the whole nerve head or disc) is about 1/3 or 0.3. There is some normal variation here, with some people having almost no cup (thus having 1/10 or 0.1), and others having 4/5ths or 0.8 as a cup to disc ratio.

How do you identify an optic cup?

Optic cup depth depends on the cup area in normal eyes. This means that a larger cup has a deeper cup. In normal eyes, CDRs are larger horizontally than vertically. In normal eyes, the shape of the optic cup is horizontally oval as the vertical optic disc diameter is about 8\% higher than the horizontal ones.

What is optic nerve?

(OP-tik nerv) The nerve that carries messages from the retina to the brain. Enlarge. Anatomy of the eye, showing the outside and inside of the eye including the eyelid, pupil, sclera, iris, cornea, lens, ciliary body, retina, choroid, vitreous humor, and optic nerve.

How is the optic cup formed?

During embryonic development of the eye, the outer wall of the bulb of the optic vesicles becomes thickened and invaginated, and the bulb is thus converted into a cup, the optic cup (or ophthalmic cup), consisting of two strata of cells.

Does cup-to-disc ratio improve?

Clinical improvement in visual fields was correlated with the degree of improvement of cup:disc ratio (P = 0.025). Conclusion: Most patients showing a 40\% lowering of IOP after glaucoma surgery show improved optic nerve morphology as measured by the HRT.

What does a small cup-to-disc ratio mean?

Thus, a normal, large disc will have a large cup, and a normal, small disc will have a small cup. This means that it is possible for a patient with a small optic disc and a small C/D ratio, such as 0.3, to have glaucomatous optic neuropathy.

How is optic disc measured?

Probably the most accurate way to manually measure the optic disc is to do high-plus non-contact funduscopy using a 78- or 90-D lens and a slit lamp. To do this, simply bring the disc into view with your high plus lens using a narrow slit lamp beam.