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What is Diameter of the optic disc is and explain in detail?
Optic disc: It is a pink coloured, well-defined circular area of 1.5-mm diameter. At the optic disc all the retinal layers terminate except the nerve fibres, which pass through the lamina cribrosa to run into the optic nerve. A depression seen in the disc is called the physiological cup. The central retinal aery and vein emerge through the centre of this cup. Macula lutea: It is also called the yellow spot. It is comparatively deeper red than the surrounding fundus and is situated at the posterior pole temporal to the optic disc. It is about 5.5 mm in diameter. Fovea centralis is the central depressed pa of the macula. It is about 1.5 mm in diameter and is the most sensitive pa of the retina. Reference :- A K KHURANA; pg num:-249