1. Copper wiring, silver wiring and focal narrowing of retinal vessels, microaneurysms, streak and blot hemorrhages, hard and soft exudates in retina in hypertension.
2. Elschnig's spots in choroid in hypertension.
3. Anterior ischemic optic neuropathy and disc edema in optic disc in hypertension.
I think it is due to vascular difference in these three areas 1. non-leaky vessels in retina. 2. leaky vessels in choroid and 3. presence of both features in vessels of optic nerve head.
@ syed Imtiaz Ali Shah
can you explain your idea in details, sir?
Just a thought, Syed Imtiaz Ali Shah , I think it is due to difference in the embryogenesis of those different layers. The genetics may be different for them to respond distinctly from each other.
Dear Mohamed Nagy Elmohamady, if you concentrate on the capillaries of retinal circulation you will find them non-leaky due to tight junctions between the lining cells, however if you look into the choroidal capillaries you will find them very leaky due to fenestrations instead of tight junctions. Therefore, in retina, when blood pressure rises the resistance to circulation is increased leading to thickening of walls of retinal arterioles and their subsequent narrowing and more increase in resistance to blood flow. This vicious phenomena results in characteristic retinal changes already mentioned. However fenestrations in capillaries of choroid take the opposite path. If you concentrate on optic nerve head, you will find the anterior part being supplied by retinal circulation whereas posterior part is supplied by choroidal circulation, leading to a different (mixed) behavior of optic nerve head to hypertension.
Dear Pabita Dhungel, you are right as every thing finally takes origin from genetics.
This is a very interesting question. All the above answers given are applicable.
The calibre of the blood vessels ( capillaries , arteries and veins) are diffetent sizes and their tight junctions or fenestrations are also factors to be considered in hyperetnsion .
Vascular response is similar in all structures. It is only clinical presentations which are different.
Vascular response does vary , e.g. age of the individual , co-morbidities, medication factors, stress factors etc.
Dear Pir Salim Mahar and Ramesh Seewoodhary I am learning from you both, its fascinating discussion.
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