Where in the retina are cone cells predominantly found?
Centrallly - highest at the fovea
Where in the retina are rod cells predominantly found?
In the periphery
Which cells of the retina are responsible for the ‘sensor surround effect’?
Horizontal cells
Where in the brain do ganglion cells project to?
Suprachiasmatic nuclei
Which cells contain melanopsin?
Retinal ganglion cells
Which photopigment is involved with the regulation of circadian rhythm?
Melanopsin
Explain the phototransduction pathway
- light hits rhodopsin and 11-cis-retinal in the disc of rod cell
- change in conformation –> all-trans-retinal
- transducin detaches –> α subunit binds to phosphodiesterase
- phosphodiesterase changes cGMP –> GMP
- Na+ channels close as cGMP no longer bound
- no Na+ means hyperpolarisation = off –> which turns bopolar cells on
- signal transduction
What is RAPD?
Relative afferent pupil defect - lesions anterior to the chiasm eg in neuritis and MS
What is protanopia?
Red visual weakness
What is deutranopia?
Green visual weakness
What is tritanopia?
Blue visual weakness
Which nucleus in the mibrain is involved in the visual pathway?
Edinger-Westphal
Where do the oculomotor efferents synapse with short ciliary nerves?
Ciliary ganglion
Loss of vision in the right eye - where in the visual pathway is the defect?
What could cause this?
Right optic nerve
- compressive tumour
- optic neuritis
- anterior ischaemic optic neuropathy
Loss of peripheral vision - where in the visual pathway is the defect?
What could cause this?
Defect in the optic chiasm
- Parasellar mass
Loss of nasal vision in the R eye and loss of temporal vision in the L eye - where in the visual pathway is the defect?
What could cause this?
Defect in the right optic tract
- neoplasm
- inflammatory process
- arteriovenous malformation
Loss of vision in the upper left quadrant of L and R eyes - where in the visual pathway is the defect?
What could cause this?
Lesion in the upper right optic radiations
- neoplasm
- inflammatory process
- ischaemia
- infection
What protective molecules/cells are in tears?
(7 listed)
- Lactoferrin
- lysozyme
- β-lysin
- IgA
- IgG
- complement
- leukocytes
What causes primary open angle glaucoma?
Decreased outflow of aqueous humour through tebecular meshwork
What is timolol and what is it used to treat?
β- blocker used to treat primary open angle glaucoma
Where is the vision loss in age related macula degeneration?
Central
What are drusen and in which condition are they found?
Lipfuscin deposits - found in dry macula degeneration
What is the cause of wet macula degeneration?
Neovascularisation from the choroid layer which has severe impact on central vision
How does lucentis work in macular degeneration?
Binds to VEGF-A which prevents it from binding to its receptor. Normally involved with neovascularisation and angiogenesis
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137 Gout57
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141 Diabetes51
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101 Diarrhoea66
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Lungs72
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139 Influenza52
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140 Sepsis50
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102 Inflammation16
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126 Angina70
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128 Endocrine83
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ICM + Data41
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Antibiotics22
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138 Testicular lump and bone pain31
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130 Sudden visual disturbance41
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104 Suicide and Self harm31
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Renal colic and hypovolaemia53
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118 Pyrexial illness20
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119 Shoulder trauma55
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118 Pregnancy23
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122 Biliary and pancreatic function25
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113 - Syncope and heart block27
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111 Obesity57
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110 Peripheral neuropathy35
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108 Normal Child and 121 Growth faltering43
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124 - Vaccination61
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142 - IBD78
