Neuroconduction of Retina
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3 neurons:
- Photoreceptor
- Bipolar
- Ganglion cell
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Supporting tissue:
- Müller cell
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Rod (scotopic vision)
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Cone (photopic vision)
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Connecting cell between photoreceptor and ganglion
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Conduct to brain
Vasculature of Retina
- Inner layer → central retinal vascular system
- Outer layer → choroid (ciliary vascular system)
- Macula lutea → choriocapillaries
Retina Barrier
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Inner barrier ( blood-retina barrier )
- Dense connection of retinal capillary endothelium
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Outer barrier ( choroid-retina barrier )
- Zonula occludens between the RPE
RPE- Bruch’s membrane- choriocapillaries complex
Symptoms
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Visual impairment
- Related to lesion site
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Metamorphopsia
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Flickering
- Vitreous traction to the retina
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Macropsia
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Micropsia
- Retina edema → fewer cones stimulated → micropsia
Signs
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Intracellular edema
- Retinal artery occlusion: ischemia leads to edema of bipolar cell, ganglion and RNFL
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Extracellular edema
- Capillary endothelium injury, and then exudation
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Cystoid macular edema
- Henle’s fibers are radially located; This pooling forms a flower-petal pattern.
Intracellular Edema
Extracellular Edema
Exudates
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Leakage of capillary → absorb → deposition of lipid in outer plexiform layer
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Since be called “soft exudation”
- Precapillary arteriole occlusion → axoplasmic transport blocked → organelles stack