In the most refractive eyes the peak sensitivity of retinal rods and cones pigment is?
Ans. d (498 and 555 respectively). (Adler's Physiology of the Eye 11th/Pg.529)# Peak sensitivity for cones = 555 nm, but combination of R, B, and G cones (cones short wavelength - 420, cones middle wavelength - 534, and cones long wavelength 564).# Peak sensitivity for rods = 498 nm.FUNCTIONALLY THERE ARE TWO SEPARATE RETINAS:Night retinaDay retinaRodsConesNo colorComplete colorLow acuity (fovea blind)High acuityScotopic or mesopic with luminance < 3 cd/m2Photopic# Photoreceptor density - Because rods and cones have different spectral sensitivities and different absolute sensitivities to light, the visual response is not the same over the retina.- Rods -130,000,000.- Cones - 7,000,000.# Cones are concentrated in the fovea and receptive fields are small in this region.# Rods are absent in macula leutea (Yellow pigment).Adaptation# Cones adapt more rapidly than rods.# Cones regain complete sensitivity in 10-12 minutes.# Rods regain complete sensitivity in 30-60 minutes
260 and 500 respectively
460 and 480 respectively
398 and 550 respectively
498 and 555 respectively
Retina