eye disorders
Blurred Vision
Evaluation of Blurred Vision
The following information can help people decide when a doctor's evaluation is needed and help them know what to expect during the evaluation. In people with blurred vision, certain symptoms and characteristics are cause for concern. They include Sudden change in vision Severely reduced vision, particularly in only one eye, even if the symptoms began gradually Eye Pain (with or without eye movement) Loss of a specific area in the field of vision (called a visual field defect) Conditions that affect the immune system (for example, use of chemotherapy or other immune-suppressing medications) People who have warning signs should usually go to an emergency department right away. People who have a bodywide (systemic) disorder that sometimes causes retinal damage (for example, diabetes, high blood pressure, or sickle cell disease) should see an eye doctor as soon as is practical, usually within a few days. However, if vision has been deteriorating gradually for months or years but has not been severely impaired and there are no warning signs, waiting a week or longer is usually not harmful. Eye examinations should be done by an ophthalmologist or optometrist. Ophthalmologists are medical doctors who specialize in the evaluation and treatment (surgical and nonsurgical) of all types of eye disorders. Optometrists are health care practitioners who specialize in the diagnosis and treatment of Overview of Refractive Disorders (which are treated by prescribing glasses or contact lenses). However, optometrists can often diagnose certain other eye problems and then refer people to an ophthalmologist for treatment. People should usually see an ophthalmologist if they have warning signs. Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the blurred vision and the tests that may need to be done (see table). Doctors ask many questions about the person's symptoms because it is important to understand exactly what the person means by blurred vision. For example, people who have actually lost vision in part of their visual field (visual field defect) may describe this sensation only as blurred vision. The presence of other eye symptoms, such as Eye Redness , Doctors also ask questions about symptoms of possible causes and about the presence of disorders that are known to be risk factors for eye disorders (for example, high blood pressure, diabetes, HIV infection or AIDS, and sickle cell disease). Examination of the eyes may be all that is necessary. Testingvisual acuity(sharpness of vision) is the first step. Ideally, acuity is measured while the person stands about 20 feet (6 meters) from a standard eye chart (Snellen chart) posted or projected on a wall. If this test cannot be done, near acuity is measured using a near card chart held about 14 inches (36 centimeter) from the eye. Each eye is measured separately while the other eye is covered. Visual acuity is measured with the person's own glasses, if such are worn. Sometimes the doctor has the person look through a device that has a pinhole. This device can usually correct refractive errors almost completely but does not correct vision that is blurred due to other causes. is also important. The doctor carefully examines the entire eye using an What Is a Slit Lamp? (a light with magnifying lenses that shines into the back of the eye), Symptoms and findings during the eye examination often help suggest a cause. For example, if visual acuity returns while corrective lenses or a pinhole device is used and the remainder of the eye exam is normal, simple Overview of Refractive Disorders is usually the cause of blurring. In a person who has a sudden, urgent illness, the symptoms of farsightedness may be more noticeable, even in those around age 40 who had never previously needed corrective lenses for reading. Previously unrecognized farsightedness is a common cause of blurred vision in hospitalized people. ). People with symptoms of bodywide (systemic) disorders should have appropriate testing. For example, testing might include blood tests for diabetes, Systemic Lupus Erythematosus (SLE) , or HIV infection, and blood pressure monitoring. 