Changes in vision can range from mild to severe, and may be lasting or only temporary. For example, a person may become completely blind or may have poor vision only under certain conditions.
What is going on in the body?
Common vision changes can include - but are not limited to:
- blurry vision
- double vision
- cloudy vision
Vision changes can be caused by anything from normal aging to life-threatening conditions. The exact changes in the body will depend on the specific cause and type of vision change.
What are the causes and risks of the condition?
The possible causes of vision changes include:
refractive errors, such as being nearsighted, farsighted or having presbyopia. A person with presbyopia has a hard time seeing things up close, due to age-related changes in the eye. This condition affects most people over age 50. This is the reason older people often need bifocals or reading glasses.
infections of the eye, such as conjunctivitis or keratitis
cataracts, a common condition in older adults caused by changes in the lens of the eye
glaucoma, a condition caused by increased pressure within the eye
damage or inflammation of the nerves of the eye
damage to the vision areas of the brain, due to a stroke or brain tumor
damage to the retina, the part of the eye that is similar to the film inside a camera. The retina can be damaged in diabetes, macular degeneration, or retinal detachment.
trauma, or injury, to the eye
strabismus, sometimes known as lazy eye, in which the eyes fail to line up properly
temporal arteritis, an inflammation of the arteries that supply blood to the eye
vitamin A deficiency
- medicines, such as the heart medicine digoxin (i.e., Lanoxin), or the antibiotic ethambutol (i.e., Myambutol)
Other causes of vision changes are possible. Sometimes, no cause can be found.
What can be done to prevent the condition?
Prevention depends on the cause. Early detection and treatment of glaucoma can often prevent vision loss. Control of diabetes can help prevent vision changes caused by diabetic retinopathy. Frequent hand washing and not touching the eyes with the hands helps prevent conjunctivitis. Many cases of vision changes cannot be prevented.
How is the condition diagnosed?
Any change in vision should be evaluated medically. A history and physical exam, including an examination of the eye, are done first. In an eye exam, the person may be asked to read an eye chart. Special instruments may be used, and the pressure inside the eye may be measured. Eye drops can be put into the eye to make the pupils get bigger. This helps the eye care professional see the inside of the eye better.
The eye care professional will need to know the kind of vision changes the person has noticed. He or she will also ask:
when the vision change started
whether it came on quickly or slowly
whether one or both eyes are affected
whether near vision, far vision, or both, is affected
whether there is any pain associated with the vision change
what medicines the person takes
what other medical conditions the person has
- whether there is any family history of vision changes
In addition, the eye care professional may ask about other symptoms, such as:
- muscle pains
In some cases, the diagnosis may be obvious from this history. In other cases, further testing is needed. The tests that are ordered vary, depending on the suspected cause. A cranial CT scan may be done if a brain tumor or stroke is suspected. A blood test can help diagnose temporal arteritis or diabetes.
Long Term Effects
What are the long-term effects of the condition?
Long-term effects depend on the cause. Presbyopia causes a permanent loss of vision in near objects. However, reading glasses or bifocals are the only treatment needed and there are no other long- term effects. A brain tumor can cause death. Glaucoma, macular degeneration, and diabetes can all result in permanent blindness or vision changes.
What are the risks to others?
Vision changes themselves pose no risks to others unless the person engages in dangerous activities such as driving. If the cause of the vision change is an eye infection, such as conjunctivitis or keratitis, the infection may be contagious in some cases.
What are the treatments for the condition?
Treatment is directed at the cause. Medicines are often used to control diabetes or glaucoma. Retinal detachment, cataracts, some types of glaucoma, and brain tumors can be treated with surgery. Eye infections may need to be treated with antibiotics. Nearsightedness is usually treated with glasses or contact lenses.
What are the side effects of the treatments?
Side effects depend on the treatments used. All medicines may have side effects. For example, those used to control diabetes may cause liver damage or allergic reactions. Surgery can be complicated by bleeding, infection, loss of vision, or reactions to anesthesia. Contact lenses may irritate the eyes or result in eye infections.
What happens after treatment for the condition?
Treatment varies according to the cause of the vision change. After a person gets glasses, no further treatment may be needed aside from periodic checkups. People who have diabetes or glaucoma usually need close monitoring and treatment for life. Macular degeneration often causes vision to get worse over time, so treatment may change.
How is the condition monitored?
The eye care professional should be told about any changes in vision or the responses to treatments. Repeat eye exams are advised for many causes of vision changes. Children with a lazy eye may need close monitoring along with surgery, special glasses, or a patch over one eye.
Cecil Textbook of Medicine, 1996, Bennett et al.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.