What is the healthiest cup to disc ratio?
The normal cup-to-disc ratio is less than 0.5. A large cup-to-disc ratio may imply glaucoma or other pathology.
What is a normal cup disc ratio?
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.
What causes cupping of optic nerve?
Individuals with glaucoma have increased IOP or consequent loss of blood flow to some regions of the eye, resulting in the death of optic nerve cells. The center of the optic disc (known as the cup) becomes larger, and the cup to optic disc ratio increases alarmingly. This process is referred to as optic nerve cupping.
Is cupping reversible?
Reversal of cupping has never been reported in medical treatment cases since the maximal medical treatment of any combination can’t drastically reduce IOP because of built-in safety (auto regulation) mechanism.
What is disc at risk?
Classically, the patient has a “disc at risk,” which can often be appreciated by a small cup-to-disk ratio in the unaffected eye. It is believed that this “crowding” of the optic disc makes the optic nerve more vulnerable to ischemic events in high-risk individuals.
How does the Cup to disc ratio work?
As glaucoma advances, the cup enlarges until it occupies most of the disc area. The cup-to-disc ratio compares the diameter of the “cup” portion of the optic disc with the total diameter of the optic disc.
What is the ratio of a donut hole to a disc?
Cup-to-disc ratio. A good analogy to better understand the cup-to-disc ratio is the ratio of a donut hole to a donut. The hole represents the cup and the surrounding area the disc. If the cup fills 1/10 of the disc, the ratio will be 0.1. If it fills 7/10 of the disc, the ratio is 0.7. The normal cup-to-disc ratio is 0.3.
Can a optic disc have a white Cup?
The optic disc can be flat or it can have a certain amount of normal cupping. But glaucoma, which is in most cases associated with an increase in intraocular pressure, often produces additional pathological cupping of the optic disc. The pink rim of disc contains nerve fibers. The white cup is a pit with no nerve fibers.
Can a eye have a high Cup to disc ratio?
Eyes with physiologically high cup-to-disc ratios in macrodiscs should not be over-diagnosed and should not be considered to be glaucomatous, and eyes with increased intraocular pressure, small optic nerve heads, and average or low cup-to-disc ratios should not be underdiagnosed and regarded to be only ‘ocular hypertensive.’
