On perimetry, a normal subject demonstrates the physiological blind spot located approximately 15 degrees temporal to fixation. This blind spot corresponds to which anatomical feature?

• A Ora serrata
• B Fovea centralis
• C Macula lutea
• D Optic disc ✓

Explanation

The optic disc is formed where ganglion cell axons converge to leave the eye as the optic nerve. It contains no photoreceptors, so light falling on it cannot be perceived, producing the physiological blind spot projected about 15 degrees temporal to fixation. The macula lutea and fovea centralis lie at the visual axis and contain dense cones giving maximum acuity, while the ora serrata marks the anterior limit of the retina and is not represented as a scotoma.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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