Ophthalmoscopic Examination

Since mydriatic eye drops are typically not used in general practice, the view of the fundus is limited to only a section of the posterior retina. Be familiar with these features before attempting to examine the patient.

1. Unless the patient's refractive errors make it difficult to focus on the retina, it is usually best to remove your own eyeglasses for the exam.
2. After darkening the room, turn on the ophthalmoscope and shine the light on your hand or on the wall.
3. Turn the lens disc until the largest white circle of light can be seen, and the diopter indicator reads 0, meaning the ophthalmoscope lens is neither converging nor dispersing the light.
4. Keep your index finger on the lens disc during the exam, so the diopters can be adjusted as necessary to focus in on the retinal structures.
5. To examine the patient's right eye, hold the ophthalmoscope in your right hand and look through the aperture with your right eye; to exam the patient's left eye, hold the ophthalmoscope in your left hand and look through the aperture with your left eye. This avoids bumping noses with the patient.
6. Position yourself about a foot from the patient at eye level, and ask the patient to stare at a spot on the wall just over your shoulder.
7. As you peer through the aperture, keep both eyes opened, press the ophthalmoscope firmly against your bony orbit, and hold the handle at a slight angle away from the patient's face.
8. Position the ophthalmoscope about 15° lateral to the patient's line of vision. Direct the light to the pupil and look for an orange-red glow. This is the red reflex. Note any opacity that seems to interfere.
9. Stay focused on the red reflex, and move the ophthalmoscope inward along the 15° line until you are almost on top of the patient's eye. While doing this, the optic disc and retinal vessels should come into sharp focus. The disc appears as a yellow, orange, or pinkish oval that largely fills the field of view.
10. If the disc isn't seen right away, identify a blood vessel and follow it toward the disc. It appears to get wider if you are going in the right direction. The light may need to be dimmed in order to keep the patient comfortable and to avoid spasmodic constriction of the pupil.
11. If the disc appears out of focus, try adjusting the diopters by rotating the lens disc one or two settings in the positive or negative direction. The retina only appears perfectly sharp if neither you nor the patient have refractive errors.
12. Carefully examine the disc for outline clarity, color, relative size of the yellowish-white central cup, and symmetry with the contralateral eye. White or darkly pigmented rings and crescents are often seen around the disc and have no pathologic significance.
13. Follow the retinal vessels as they extend away from the disc in all four directions. Veins appear redder and wider than arteries.
14. Look for spontaneous venous pulsations, which appear as subtle variations in the width of the veins with each heartbeat. It's possible to discern subtle pulsations of the veins.
15. Make special note of arteriovenous (AV) crossings. Since the walls of the normal retinal arteries are transparent, only the column of blood is visible within. Veins crossing behind arteries, therefore, are normally seen right up to the column on either side.
16. Look for any lesions elsewhere in the retina, noting their size.
17. Examine the fovea and surrounding macula by asking the patient to look directly into the light. The macula often appears to shimmer.
18. Finally, look for opacities in the lens by adjusting the diopters between 10+ and 12+.
19. If the image is lost while searching the retina, it means the light fell out of the pupil as the ophthalmoscope was moved. It takes some practice to keep it inside.