Diabetic and Hypertensive Retinopathy
These conditions are very common
and thus their effects on the eye are important. The stages of damage
should be remembered, and you should be able to recognise and
distinguish the conditions on ophthalmic pictures.
Micro-aneurysms (small red circular outpouchings of the
dot and blot haemorrhages (red blots), flame shaped haemorrhages, hard
exudates (yellow/white sharply defined spots which represent lipids
leaking through the vessels). Vision is usually normal.
Cotton wool spots (larger
white spots with fluffy edges which represent infarcts of the retina),
large blot haemorrhages. 50% progress to proliferative retinopathy in
Neovascularization (new vessel formation, usually occurring at the
optic disc), vitreous haemorrhage (due to bleeding from the fragile new
vessels). This predisposes individuals to retinal detachment, due to
fibrovascular bands forming around the new vessels and tugging on the
retina. Neovascularization can be prevented by laser ablation of
ischaemic areas (ischaemia is the stimulus for the vessel formation).
Causing loss of vision.
Diabetics are additionally more
prone to complications including glaucoma and cataracts.
Increased tortuosity and reflectiveness (known as silver wiring).
Flame shaped haemorrhages,
cotton wool spots.
include retinal vein and artery occlusion, ischaemic optic neuropathy
and vitreous haemorrhage.
The patient experiences preceding photopsia (flashes of light) and
"floaters" (visual opacities from haemorrhage). Next a "shadow" spreads
across the field of vision. Central vision is lost as the macular area
is affected. Blindness may develop in severe cases.
Associated with: diabetes mellitus, macular degeneration,
retinoblastoma, uveitis, and trauma.