Fundoscopy, also called ophthalmoscopy, is a non-invasive examination allowing a clinician to view the back of the eye, known as the fundus. This procedure provides a direct look at the retina, optic nerve, and blood vessels. By inspecting these structures, healthcare providers can identify signs of various eye conditions and even systemic diseases. The examination offers insights into a patient’s overall health.
The Fundoscopy Procedure
To prepare for a fundoscopy, a clinician will often administer eye drops to dilate the pupils. These drops may cause a brief stinging sensation. Dilation is necessary to provide a clearer and more expansive view of the fundus. The effects of these drops are temporary but result in significant light sensitivity and blurred near vision, lasting for several hours.
The examination itself is painless and takes between five to ten minutes. It is conducted in a darkened room to improve visibility for the examiner. The patient will be seated and asked to look in various directions while the clinician shines a bright light into the eye. The brightness can be uncomfortable and may leave temporary after-images, but it does not cause pain.
There are a few different methods for performing a fundoscopy. Direct ophthalmoscopy involves a handheld instrument called an ophthalmoscope, which provides a highly magnified view of a small area of the retina. For a wider, three-dimensional view, a practitioner may use indirect ophthalmoscopy. This technique involves a light source worn on the head and a separate condensing lens held near the eye, which is particularly useful for detecting issues in the peripheral retina, such as retinal detachment. Following the procedure, patients will need to wear sunglasses and arrange for someone to drive them home due to the lingering effects of the dilating drops.
Conditions Detected by Fundoscopy
A fundoscopic examination is instrumental in diagnosing and monitoring various medical conditions affecting the eye. One of the most common is diabetic retinopathy, a condition where high blood sugar levels damage the retinal blood vessels. Fundoscopy can reveal microaneurysms, which are tiny bulges in the vessel walls, as well as hemorrhages and other vascular abnormalities.
The exam is also used for detecting glaucoma, a condition characterized by damage to the optic nerve, often associated with increased pressure inside the eye. Another condition, age-related macular degeneration (AMD), can be identified by the presence of yellow deposits called drusen under the retina. Furthermore, the procedure can spot a retinal detachment, where the retina pulls away from its normal position.
Beyond primary eye diseases, fundoscopy can reveal evidence of systemic health problems. For instance, chronic high blood pressure, or hypertension, can cause the arteries in the retina to become narrow and stiff, a condition known as hypertensive retinopathy. These findings provide a direct window into the health of blood vessels throughout the body.
Interpreting the Results
During the examination, the clinician evaluates the primary structures of the fundus: the retina, the optic disc, and the blood vessels. A healthy fundus has a distinct appearance. The retina should be a consistent orange-pink color, and the optic disc—the circular area where the optic nerve connects to the retina—should be pale pink with sharp margins. The network of retinal arteries and veins should have a normal size ratio and show no signs of leakage or blockage.
Abnormal findings are interpreted in the context of specific conditions. For example, an enlargement of the pale center of the optic disc, known as the “cup,” results in an increased cup-to-disc ratio, a sign of glaucoma. In cases of diabetic retinopathy, the presence of dot and blot hemorrhages or fluffy, whitish lesions called cotton wool spots indicates damage to the retinal blood vessels.
Changes in the blood vessels themselves can also signify disease. Arteriovenous nicking, where a thickened artery presses on and constricts a vein at a crossing point, is a sign of hypertensive retinopathy. A swollen optic disc with blurred margins, called papilledema, can indicate high pressure inside the brain.