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Download Anatomy and Physiology of the Retina
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Anatomy and Physiology of the Retina Associate Professor Trevor Sherwin Department of Ophthalmology University of Auckland Light entering the Eye 2 Eye Exam 3 The retina 4 Function of the retina - To absorb photons of light - Translate light into a biochemical message - Translate biochemical message into electrical impulse -Transmit electrical impulse to the brain via ganglion cells 5 Sagittal section of the retina 6 Cellular detail of the retina 7 Octopus Retina 8 Octopus Retina 9 Layers of the retina 10 Cell bodies and synapses All vertebrate retinas are composed of three layers of cell bodies and two layers of synapses Cell bodies of rods/cones Cell bodies of bipolar cells Cell bodies of ganglion cells 11 Neuropil layers Photoreceptor bipolar synapse 12 Neuropil layers Bipolar – ganglion synapse 13 Photoreceptors 14 Photoreceptors 15 Photoreceptors 16 Rhodopsin and photoreceptor cells 17 Rhodopsin 18 Central and peripheral retina 19 Central and peripheral retina 20 Optic Nerve 21 Optic Nerve 22 Blood supply to the Retina Choroid supplies 85% Mainly outer retina Photoreceptors Central retinal artery supplies 15% Inner retinal layer 23 IV Fluorescein Angiogram 24 IV Fluorescein Angiogram 25 IV Fluorescein Angiogram 26 IV Fluorescein Angiogram 27 The fovea Foveal pit + foveal slope + parafovea + perifovea = Macula 28 Eagle Vision 29 Photoreceptor cell diameter Rods (IS) – 2 microns Cones (IS) – 6 microns However, in the fovea Cones (IS) – 1.5 microns 30 Photoreceptor cell diameter Rods (IS) – 2 microns Cones (IS) – 6 microns However, in the fovea Cones (IS) – 1.5 microns 31 Photoreceptor density 32 Acuity of the retina 33 The Macula Lutea Xanthophyll caratenoids – Tapetum & lutein zeaxanthin 34 Colour Absorbancy 35 Colour Blindness Red/green colour blindness - X linked Males only have a single X chromosome Almost all genes on the X have no counterpart on the Y Any gene on X, even if recessive in females will be expressed in males 36 Summary of photoreceptors Rods - Low light levels (scotopic) Peripheral vision Slow response Cones - Visual acuity Colour vision Fast response 37 Clinical examination of photoreceptors Form & spatial vision, measured by visual acuity Reflects rod & cone distribution Colour vision testing is indicative of cone function and associated processing of the signal 38 Vision and Movement 39
