Vision Care Links
Vision Care Library
Glossary

Home
Contact Us
Products & Services
Company Profile

Vision Care.The Doorway to Better Health

The Dilated Fundus Examination Provides Information About Your Vision and Overall Health

By Robert Elsas
Vice President of Business Development, Davis Vision
By Joseph Wende, O.D.
Vice President Provider Relations, Davis Vision

When you visit your local eyecare professional, your thoughts are probably on having your vision tested, getting a new lens prescription or making sure there is no evidence of cataracts or glaucoma. But did you know that a thorough eye examination can provide clues about your overall health and signal evidence of many systemic diseases before their symptoms show up elsewhere in your body?

A dilated fundus evaluation (DFE) can do just that. An important part of a complete eye health screening, the DFE is an excellent means of detecting and assessing the signs of diseases of both the eye and the body at large. It is a very useful, painless diagnostic tool that only takes an average of five minutes to perform.

Undilated Pupil	Dilated Pupil

Dilation Makes Room for a View

The dilated fundus evaluation allows the practitioner to inspect the fundus, or back portion of the eye, which includes the retina, optic disc and blood vessels. The retina contains all of the light-sensitive receptors that enable us to see. The retinal blood vessels enter into the eye at the optic disc, the anterior surface of the optic nerve. The optic nerve is a bundle of millions of sensitive nerve fibers. The optic disc is normally smooth and round when healthy, but can become swollen and distorted from a variety of illnesses.

At the start of the procedure, medicated eyedrops are administered to dilate, or enlarge, the pupil and make the fundus easier to study. In a darkened examination room, the eyecare practitioner will focus an ophthalmoscope in each eye, one at a time. This instrument projects a beam of light and employs a magnifying lens that permits the doctor to get a good view of the back of the eye.

Getting an Eyeful of Information

DFE is considered to be one of the most valuable tests conducted during an eye examination because it can detect some signs and physiological effects of various circulatory, metabolic and neurologic disorders such as high blood pressure, diabetes and some tumors. It can also aid in the diagnosis and assessment of the following eye disorders:

• Cataracts
  This opacification of the normally clear lens of the eye mainly forms in older adults, but anyone is susceptible. Cataracts may result as a side effect of certain medications, or a complication of other systemic disease. Its typical symptoms of glare, hazy or blurry vision may be very slight during the early stages. DFE can aid the evaluation of cataracts.
  
• Cloudy Vitreous
  The vitreous is the clear, almost gelatinous substance that fills the main chamber inside the eyes. It, too, can become clouded and obscure vision by scattering light before it reaches the retina. Through a dilated fundus evaluation, the first signs of cloudiness may be seen so treatment can begin before vision is compromised.
• Retinal Tears and Detachment
  A detached retina usually occurs when there is a tear, or hole, in the retina, allowing fluid to diffuse behind it and push the retina away from the wall of the eye. Depending on its size and location, the person may not have any symptoms in the early stages. Good outcomes are dependent on early detection and repair. DFE may be the only means of detection in many cases.
• Optic Nerve Disease
  The optic nerve is the bundle of nerves that transmits signals from the retina to the brain. When it becomes damaged or swollen from disease, sight is lost because the brain may not receive all of the necessary signals. The optic nerve can be better observed through the dilated pupil and evaluated for its health.
• Glaucoma
  A leading cause of blindness, glaucoma results in damage to the optic nerve, usually associated with increased pressure within the eye. Because the disease is often asymptomatic, many people lose much of their sight before it is diagnosed. With early detection, most or all of a person's vision may be saved. Careful evaluation of the optic nerve is integral to the management of glaucoma.

The Body of Evidence

Many systemic diseases with a focal point elsewhere in the body may manifest distinctive signs in the eyes. Sometimes they present overt symptoms through the eyes; other times the illness is only apparent to a skilled eyecare practitioner inspecting the internal eye during a dilated fundus evaluation.

A common systemic disease that can be detected through this evaluation is diabetes. When the body is unable to process sugar correctly, changes in the vascular system produce microaneurysms, hemorrhages and fluid leakage into body tissues, including the retina. Visual impairment is a frequent complication of diabetes.

According to the American Diabetes Association, more than 70 percent of people with diabetes develop some diabetic eye disease after having the disease for 20 years. Diabetic eye disease can include cataracts, glaucoma, macular degeneration, retinal hemorrhages and retinal detachment. If the condition is not diagnosed and treated early, blindness often results. Diabetes remains the leading cause of adult blindness in America. Approximately 8,000 diabetes sufferers lose their vision each year due to retinal complications.

Annual eye examinations including a dilated fundus evaluation are a critical component of diabetic care. Without dilation of the pupil, early stages of diabetic retinopathy may be missed. Through a dilated fundus evaluation, the changes that occur in retinopathy can be seen and monitored sooner. With early detection, these complications are more effectively managed. Studies show that 90 percent of blindness due to diabetes can be prevented with early detection and intervention.

Risk factors for other diseases, including hypertension and elevated cholesterol levels, are often identifiable in the eyes as well. Hypertension produces a narrowing of the arteries when blood pressure is significantly elevated. This can lead to hemorrhages in the retina. The appearance of retinal hemorrhages due to hypertension can be easily distinguished from hemorrhages due to diabetes during a dilated fundus evaluation.

Increased levels of lipids and cholesterol may result in plaques or clots in retinal blood vessels, indicating potential risk of stroke. These plaques may also be observed and detected during a dilated fundus evaluation.

Neurological disorders, such as Multiple Sclerosis and space occupying tumors in the brain often cause swelling and inflammation of the optic disc. Additionally, subtle changes in color vision, depth perception and peripheral vision may be early signs of neurologic disorder. Early detection and effective management of these potentially life threatening conditions can be facilitated through a thorough eye examination.

Eye Exams are Essential to Overall Health

The American Optometric Association recommends that adults between the ages of 18 and 60 have their eyes examined at least every two years, and that those over the age of 60 take an annual trip to their eyecare professional. It's essential to make a complete eye examination part of a total healthcare routine whether or not vision correction is needed.

Many diseases that may be easy to miss in their early stages are evident with a thorough eye examination. And a number of these ailments-either of the eye or the rest of the system-can have disastrous effects if they are not detected and treated promptly. Regular visits to an eyecare professional can keep not only the eyes but the entire body in better health.

"Nothing on this web site is intended, nor should it be construed, as professional advice. Those reviewing the information should consult with a qualified professional."