My husband had severely blurred vision in one eye. The diagnosis was ocular edema. Please explain this condition. Also, is there any possible connection with medication for high blood pressure?

L.B.

Edema is a medical term for swelling. In the eye, there are two main types of edema: swelling of the retina (macular edema) and swelling of the cornea (corneal edema).

Macular edema is a painless condition in which the central retina becomes swollen, causing blurry vision. There are numerous causes of macular edema, including infectious and inflammatory conditions. However, the most common cause of macular edema in the United States is when diabetes affects the eyes. There are many medications that can be used for macular edema, and the choice depends on the cause of the swelling. In addition, there are situations in which laser treatment is the best choice to improve the vision of a person with macular edema.

Swelling can also affect the cornea, which is the clear coating on the front of the eye. The most common causes of this kind of swelling are infections or postsurgical complications, such as after cataract-removal surgery. A swollen cornea is often associated with eye discomfort and can also cause blurry vision. Again, the treatment of this type of edema depends on the cause. For example, an infectious cause of corneal edema needs to be treated with antibiotic eyedrops. For generalized swelling of the cornea after surgery, eyedrops that contain 5 percent sodium chloride may help. These drops reduce swelling by causing dehydration of the cornea. If corneal swelling does not respond to eyedrops and severely impairs vision over the long term, a corneal transplant may be necessary. In this operation, doctors remove the swollen cornea and replace it with a cornea donated by someone who has died. The new cornea will eventually allow for better vision once it heals after surgery.

As for your final question, to my knowledge, neither macular edema nor corneal edema has been linked to the use of blood pressure medications.