What does small optic nerve mean?
The optic disc appears abnormally small, because not all the optic nerve axons have developed properly. It is often associated with endocrinopathies (hormone deficiencies), developmental delay, and brain malformations.
What does large optic disc mean?
However, the appearance and size of the optic disc varies widely among healthy individuals. In studies using planimetric measurements from color photographs, the optic disc area was found to range from 0.8 mm to >6.0 mm2 in a healthy white population.
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.
What happens if you have a small optic nerve?
Most people with ONH have abnormal eye movements (nystagmus) and vision can range from no light perception to good functional vision, or even full vision in one eye. Children with ONH may have brain malformations and pituitary problems.
What is normal size of optic nerve?
The normal optic nerve head diameter varies in size from 1.2 to 2.5mm. There is some inconsistency in the literature as to what cutoffs to use for a small or large disc, but in general a disc can be considered small if ≤ 1.2 mm and large if ≥ 1.8 mm.
What size should your optic nerve be?
What is optic disc VS 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.
What are the symptoms of ONH?
Most infants with ONH have involuntary, rapid eye movements (nystagmus) and/or mild to severe visual impairment of one or both eyes. Vision often improves modestly in early childhood even though there is no growth of the optic nerves after birth.
What is a normal optic disc?
The normal optic disc is oval and about 1.5 mm in vertical diameter. It is located in the nasal hemi-retina and the corresponding blind spot in the visual field lies between 10 and 15° from fixation in the temporal hemi-field, usually slightly below the horizontal meridian .
What is a small optic nerve called?
Optic nerve hypoplasia ( ONH) is a medical condition arising from the underdevelopment of the optic nerve (s). This condition is the most common congenital optic nerve anomaly. The optic disc appears abnormally small, because not all the optic nerve axons have developed properly.
Where is the optic disk located?
The optic disk can be seen in the back of the eye with an ophthalmoscope. It is located on the nasal side of the macula lutea, is oval in shape, and is approximately 1.5 mm (0.06 inch) in diameter.
What does the optic disk do in your eye?
The main purpose of the optic disc is to transmit electrical impulses from the eyes to the part of the brain that accepts and comprehends the information. Miami eye doctors will also inform curious patients that the optic disc consists of over one million nerve fibers and is comprised entirely of nerve cells.