Hypertension, most commonly referred to as "high blood pressure", or HTN, is a medical condition in which the blood pressure is chronically elevated.
How can high blood pressure affect the eyes?
Hypertension or high blood pressure leads to many changes in the blood vessels of the body. These same changes in blood vessels affect the eyes in many ways. They can cause the following problems:
- Hypertensive retinopathy
- Branch retinal vein occlusion (BRVO) and vitreous hemorrhage
- Optic nerve involvement (Optic neuropathy)
- Involvement of the nerves supplying the eye muscles, leading to temporary paralysis or weakness of these muscles
What are the symptoms of these conditions?
Many of these conditions may not have any symptoms in the initial stages. Therefore, it is important to have a periodic eye exam to detect them.
Branch retinal vein occlusion (BRVO) may lead to a blurring of vision, especially for fine work. A vitreous hemorrhage may lead to a more severe loss of vision associated with a shower of red floaters. Optic neuropathy may also lead to a loss of vision, which is painless and not associated with any floaters. Paralysis or weakness of the muscles of the eye leads to restriction of movement of the eye and double vision.
What is the role of laser in treatment of eye disease because of high blood pressure?
BRVOs are commonly associated with high blood pressure and changes of hypertensive retinopathy. This condition may lead to loss of vision by a few mechanisms:
Macular edema (swelling of the region of macula): The macula is the central region of the retina and is important for seeing fine details. A swelling in this region leads to a decrease in vision. This condition can be treated with laser therapy.
Vitreous hemorrhage: Sometimes a BRVO may lead to formation of new vessels in the retina. These vessels are abnormal and very fragile. They may bleed, causing vitreous hemorrhage and loss of vision. With timely detection, these new vessels can be eliminated via laser therapy.
Macroaneurysm: This is an uncommon manifestation of hypertension. Untreated, this may cause bleeding into vitreous and thus result in a loss of vision. This condition can be treated with laser therapy.
Why is an eye checkup important if one has hypertension?
The eye is the only organ of the body where one can observe the blood vessels directly. By examining your eyes, our optometrists may observe the changes in blood vessels caused by hypertension. This also provides information about the severity of the disease elsewhere in the body.
Moreover, presence of swelling of the disc (grade 4 hypertensive retinopathy) is an indicator of a very severe, life threatening rise in blood pressure, which warrants emergency treatment.
If a patient has both hypertension and diabetes, can both these diseases affect his/her eyes?
Yes. A patient may have changes of both diabetic retinopathy and hypertensive retinopathy. In fact, presence of hypertension may lead to exacerbation of the changes due to diabetic retinopathy. Therefore it is important to control the blood pressure in a patient with diabetic retinopathy.