Ipoh Echo’s EYE HEALTH series continues with Consultant Eye Surgeon Dr S.S. GILL talking to us more about hypertension and the eyes.
Hypertensive Retinopathy is the sequelae of high blood pressure in the eyes. High blood pressure, also called hypertension, affects 40% of people above the age of 25 years by WHO’s estimates. Hypertension damages blood vessels and these are easily seen in the eyes. Both duration of hypertension and also the severity of hypertension play a role in determining the extent of damage to blood vessels in the eyes. Other illnesses that play a part in accelerating the damage are diabetes mellitus, hypercholesterolemia (increased cholesterol levels) and smoking.
DAMAGE TO THE EYES
There are several serious effects of hypertension that may occur in the eyes. Among them are:
Retinal Artery Occlusion – blockage of the arteries to the eye (retina).
Retinal Vein Occlusion – blockage of the veins draining the blood from the retina.
Ischaemic Optic Neuropathy – poor blood flow to the eye causing optic nerve damage.
When these occur, it just means that it has reached a complication stage of hypertension. It is best to be examined from time to time in order to prevent eye surprises like these.
RETINAL ARTERY OCCLUSION
This is very serious because it results in sudden profound loss of vision in the affected eye. Essentially, this may be summarized as an ocular stroke. It is an eye emergency and any delay in treating this results in permanent loss of vision in the affected eye. Quick treatment improves the chances of recovery but even this is only by about 20 to 25%!
Should this happen to an individual, a thorough cardiovascular assessment will need to be done as this condition is an ominous sign of potential vascular complications to the organs. If the artery involved is the main artery (Central Retinal Artery Occlusion), the vision loss is profound. The retina when examined will show the cherry red spot sign (see pic). If it is the branch that is involved (Branch Retinal Artery Occlusion), the vision loss is less profound.
RETINAL VEIN OCCLUSION
The occlusion or block may affect either the main retinal vein (Central Retinal Vein Occlusion) or one of it’s branches (Branch Retinal Vein Occlusion). If it is the main vessel, again the visual effects are more serious than if a branch is affected. A vein occlusion is still the lesser of the two evils if it is compared to retina artery occlusion described above.
ISCHAEMIC OPTIC NEUROPATHY
Ischaemia means a decrease in the supply of the blood to an organ. In this case, there is a lack of blood supply to the main nerve of the eye (Optic Nerve), therefore affecting the nerve function and of course in turn affecting the vision.
Should any of the above three conditions occur, it just means that the hypertension is advanced. All the above conditions may cause blurring vision, double vision, blood headaches or even sudden loss of vision. Prompt diagnosis of hypertensive retinopathy is important in order to avoid visual and systemic morbidity such as heart disease, strokes and renal disease. If you suffer from hypertension, it is advisable to get your eyes checked at least once a year before any of these eye conditions occur.