Hypertensive retinopathy
 

A grade 3 hypertensive retinopathy A grade 4 hypertensive retinopathy showing disc oedema and hard exudate at the macula

Nowadays it is uncommon to encounter malignant hypertension due to good screening programme and effective  treatment for high blood pressure. However, you must be able to recognize the features of hypertensive retinopathy  especially that of malignant hypertension. Early hypertensive retinopathy (grade 1 and 2) are commonly seen in the  presence of other retinal conditions such as branch retinal vein occlusion, branch retinal artery occlusion or  macroaneurysm. In the examination, if the main focus is on hypertensive retinopathy the patient usually has grade 3 or 4 hypertensive  retinopathy. In grade 3: there are retinal arterioles narrowing with artero-venous nipping. The retina contains  flame-shaped and blot haemorrhages, cotton-wool spots and hard exudates in the macula which may be star-shaped. In grade 4: features of  grade 3 plus papilloedema.

Questions:

1. How can hypertension affect the eye?

Answer
In addition to hypertensive retinopathy, hypertension is associated with:
central retinal venous/arterial occlusion
anterior ischaemic optic neuropathy
macroaneurysms
focal infarction of the choriocapillaris (Elschnig's spots)
serous detachment of the retina
vitreous haemorrhage
cranial nerve palsies
cerebrovascular events affecting the visual pathway and cortex

2. What are the retinal features of hypertension?

Answer
Two main features of hypertensive retinopathy are vasoconstriction and vascular leakage. Hypertension can be graded as follow according to the retinal appearance:
Grade 1: mild generalized arteriolar attenuation
Grade 2: grade 1 + deflection of veins or A-V (arterio-venous) nipping at the A-V crossing
Grade 3: grade 2 + retinal haemorrhages, cotton wool spots, retinal lipid exudates and oedema
Grade 4: all the above features and optic disc swelling (malignant phase)

Note: Although standard textbook mentions the appearance of the arterioles as having 'copper-wire' and 'silver-wire' appearance in grade 2 and 3 stages respectively. This is difficult to discern in clinical practise and is probably best avoided in your clinical examination unless the examiners ask for them.

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