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Meaning
The optic nerve head, or optic disc, is the exit point for ganglion cell axons exiting the eye. The optic disc pertains to a tiny blind spot for each eye since it does not contain rods or cones.
The junction of the retinal ganglion cell axons occurs at the optic disc, the origin of the optic nerve (second cranial nerve). The primary blood arteries that nourish the retina also enter the optic disc.
1 to 1.2 million afferent nerve fibres are transported from the eye to the brain by the optic disc in a normal human eye.
Structure
The optic disc is located 3-4 mm to the nasal region of the fovea. It is of a vertical oval shape with average measurements of 1.76 mm horizontally and 1.92 mm vertically. The optic cup is a core depression that varies in size. This depression can take several forms, from a shallow depression to a bean pot; the shape can be important for determining the presence of certain retinal diseases.
The only area of the retina that lacks photoreceptors is the optic disc, which is why it is referred to as the “blind spot” of the eye.
Optic Disc Function
The optic nerve, which exits the eye at the optic disc, sends all visual data to the brain. The optic disc signifies the beginning of the optic nerve when signals from rod and cone cells exit the eye and travel through nerve fibres to the brain’s optic centre. This region is frequently referred to as the “blind spot.”
The optic disc has significant clinical implications since it is visible during a clinical examination (ophthalmoscopy). The initial symptom of elevated intracranial pressure may be the swelling of the disc, commonly known as disc oedema or papilloedema. Additionally, the disc’s structural abnormalities may indicate high intraocular pressure.
Standard optic discs are pink to orange in colour, though this might change depending on ethnicity. A pale optic disc is a disc whose colour ranges from a light shade of orange or pink to white. A pale disc is a sign of a medical condition. An optic disc haemorrhage is a significant independent risk factor for the decline of the visual field.
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