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. It can cause the following problems in the eye:

• Hypertensive retinopathy
• Macroaneurysms
• 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 checkup to detect these.

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?
Branch retinal vein occlusion (BRVO) is a condition that is commonly associated with high blood pressure and changes of hypertensive retinopathy. This condition may lead to loss of vision by two mechanisms:

• Macular edema (swelling of the region of macula): 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 by doing laser therapy and intravitreal antiVEGF agents.
• Vitreous hemorrhage: Sometimes the BRVO may lead to formation of new vessels in the retina. These vessels are abnormal and are very fragile. These may bleed and may cause vitreous hemorrhage and thus loss of vision. A timely detection of these new vessels can be treated by doing laser therapy as well as injections of anti VEGF agents in the eye and thus causing these new vessels to disappear.

Macroaneurysm: This is an uncommon manifestation of hypertension. Untreated, this may cause bleeding into vitreous and thus loss of vision. This condition can be treated by laser therapy.

Why is eye checkup important if one has hypertension?
Eye is the only organ of the body where one can observe the blood vessels directly. Seeing the retina by using ophthalmoscope, we can see the blood vessels. Thus examination of the eyes help the physician or ophthalmologist to observe the changes in blood vessels because of hypertension. This gives an idea 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 to control the blood pressure.

If the patient has both hypertension and diabetes, can both these diseases affect his/her eyes?
Yes. The patient can have changes of both diabetic retinopathy as well as 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.