Anatomy and Physiology of the Retina...Anatomy and Physiology of the Retina Associate Professor...
Transcript of Anatomy and Physiology of the Retina...Anatomy and Physiology of the Retina Associate Professor...
Anatomy and Physiology of the Retina
Associate Professor Trevor SherwinDepartment of Ophthalmology
University of Auckland
Light entering the Eye
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Eye Exam
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The retina
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Function of the retina
-Transmit electrical impulse to the brain via ganglion cells
- To absorb photons of light
- Translate light into a biochemical message
- Translate biochemical message into electrical impulse
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Sagittal section of the retina
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Cellular detail of the retina
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Octopus Retina
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Octopus Retina
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Layers of the retina
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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
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Neuropil layers
Photoreceptor -bipolar synapse
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Neuropil layers
Bipolar – ganglion synapse
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Photoreceptors
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Photoreceptors
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Photoreceptors
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Rhodopsin and photoreceptor cells
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Rhodopsin
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Central and peripheral retina
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Central and peripheral retina
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Optic Nerve
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Optic Nerve
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Blood supply to the Retina
Choroid supplies 85%Mainly outer retinaPhotoreceptors
Central retinal artery supplies 15%Inner retinal layer
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IV Fluorescein Angiogram
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IV Fluorescein Angiogram
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IV Fluorescein Angiogram
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IV Fluorescein Angiogram
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The foveaFoveal pit + foveal slope + parafovea + perifovea
= Macula
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Eagle Vision
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Photoreceptor cell diameter
Rods (IS) – 2 microns
Cones (IS) – 6 microns
However, in the foveaCones (IS) – 1.5 microns
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Photoreceptor cell diameter
Rods (IS) – 2 microns
Cones (IS) – 6 microns
However, in the foveaCones (IS) – 1.5 microns
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Photoreceptor density
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Acuity of the retina
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The Macula Lutea
Xanthophyll caratenoids –zeaxanthin & luteinTapetum
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Colour Absorbancy
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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
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Summary of photoreceptors
Rods - Low light levels (scotopic)Peripheral visionSlow response
Cones - Visual acuityColour visionFast response
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Clinical examination of photoreceptors
Form & spatial vision, measured by visual acuityReflects rod & cone distribution
Colour vision testing is indicative of cone function and associated processing of the signal
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Vision and Movement
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