What does a normal optic disc look like?
Typically the optic disc looks like an orange-pink donut with a pale centre. The orange-pink appearance represents healthy, well perfused neuro-retinal tissue. There are many pathological reasons why a disc may lose this orange-pink colour and appear pale ie optic atrophy.
What is normal optic disc size?
Measuring optic disk size is an essential part of the optic nerve head for evaluation for glaucoma. The average human optic disc dimensions are 1.88mm vertically by 1.77mm horizontally, and can be grouped by vertical diameter into small (1.2-1.7mm), average (1.87-1.96mm), and large (2.03-2.27mm) disc sizes [1].
What is normal optic disc cupping?
A C/D ratio between 0.4 and 0.8 can characterize a patient with a normal optic disc (i.e., physiologic cupping), a glaucoma suspect or someone with early to moderate glaucoma (depending on the optic disc size); If the C/D ratio is 0.8 or greater, consider the individual’s disc as glaucomatous unless proven otherwise.
How do you describe optic discs?
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 a normal disc area on Oct?
The average disk area measurement in the normal white population using the OCT ranges from 2.10 mm 2 – 2.35 mm 2. The OCT has further been shown to provide reproducible assessment of optic disk topography and retinal nerve fiber layer.
What is disc diameter?
The disc-macula: disc diameter (DM:DD) ratio is the ratio of the horizontal distance between the center of the optic disc and the macula to the mean diameter of the optic disc, as evaluated from fundus photographs.
What is cup and disc in eye?
It is composed of millions of retinal nerve fibers that bundle together and exit to the brain through the optic disc located at the back of the eye. The optic disc has a center portion called the “cup” which is normally quite small in comparison to the entire optic disc.
What is the normal AV ratio?
The ratio has been normally regarded as 2 : 3 (Leatham, 1949), 2 : 3 to 3 : 4 (Gowers, 1879; Fishberg, 1954), 3 : 5 to 5 : 5 (Nicholls, Turnbull, and Evelyn, 1956), and 4 : 5 or 5 : 5 (Wood, 1956). by ordinary ophthalmoscopy.
Is 7 a good eye pressure?
Normal IOP is usually between 12 and 22 mm Hg. Similar to using inches as a way to report length, mm Hg refers to millimeters of mercury and is a way to report pressure. An eye is considered hypotonous when the IOP drops below 10 mm Hg. However, hypotony may not be a problem unless the IOP drops below 5 mm Hg.