The optic disc lacks photoreceptors, therefore, it is the blind spot.
The macula lutea , lateral to the optic disc, is a rounded, yellowish region of the retina containing a pit called the fovea centralis (the area of sharpest vision with the highest proportion of cones and almost no rods.
The sound waves displace one region of the basilar membrane causing hair cells in the spiral organ to distort when they push against the tectorial membrane. This stimulus is converted to a nerve impulse, which travels through the cochlear nerve.
Remaining pressure wave vibrations are transferred to the scala tympani and exit the inner ear via the round window.