Indirect ophthalmoscopy is one of the most challenging but essential techniques for new residents to learn. Practice makes better — it takes extensive practice to get good, so don’t worry if it takes a while to get it right. Here are three tips to get you off to the races.
1. Get Ready …
Dilation: Make sure your patient is well-dilated with both 1% tropicamide and 2.5% phenylephrine to get the iris aperture as large as possible.
Lenses: The two main lenses used are the double aspheric 20-D and 28-D lenses. The 20-D lens is most commonly used, with up to 3.13 degrees of magnification and a 60-degree field of view. The 28-D lens is more commonly used for pediatric retinal evaluations due to its larger 69-degree field of view, despite less magnification (2.27 degrees). These features allow the 28-D lens to provide a view even with a smaller pupil.
2. Get Set …
Patient positioning: Exam chairs for ophthalmology are designed to raise up and down, swivel and recline. Use these features to recline the patient, with room for you to move around the head of the bed. Remember: Light travels in a straight line, so moving around the patient will allow easier examination of the retina on the opposite side. For example, if you want to examine the patient’s temporal retina in the right eye, stand on the patient’s left side.
Indirect headset: Center the headset on your head and adjust the oculars so that you can see out of both eyes. Most people use their thumb extended at an arm’s length to check their light and alignment, making sure they can see their thumb in the same spot from both eyes. Set the light settings to the largest size and consider turning the light intensity down to about 70%, using the yellow light or using the diffuser to improve patient comfort. In children or patients with small pupils, using a smaller light size helps with visualization.
Be sure to keep your lens perpendicular to your light and use a finger to stabilize yourself on the patient’s face. Image courtesy of Jessica Randolph, MD.
Examination: Use your thumb and forefinger to hold the lens with the silver ring pointing toward the patient. Place your pinky finger on the patient’s head for stability. Hold the lens close to the patient and move it toward you until the retina comes into view. Keep your arm extended. Beginners often move their head closer to the patient, but this disrupts the view. Keep the lens perpendicular to your light to create the best view. Do this by “aligning the stars,” or bringing the two light reflexes together on the lens itself. Establish a routine for examining each clock hour of the retina. This makes it easier to remember where you see pathology. I usually start at 12 o’clock and work my way around the retina clockwise. Don’t forget the area just temporal to the macula.
Scleral depression: Scleral depression helps reveal the most anterior parts of the retina, including the ora serrata, by deforming the globe and therefore bringing these parts into view. It also can dynamically highlight subtle retinal pathology like retinal dialyses.
With the patient looking opposite, position a scleral depressor or cotton-tipped applicator on the eyelid. Gently push inward as the patient moves the eye to bring the peripheral retina into the light beam. For example, to examine the superior retina with scleral depression, have the patient look inferiorly, place the depressor in the superior lid crease and gently press inward while the patient looks up.
When recording your findings, remember that everything in your view is upside down and backward, but in the same clock hour you are examining.
Take your time and keep practicing! Indirect ophthalmoscopy is a skill that requires repetition to perfect. You can do it!
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Jessica D. Randolph, MD,
is a vitreoretinal surgeon, assistant professor of ophthalmology and medical student educator at Virginia Commonwealth University in Richmond, VA. She joined the YO Info
editorial board in 2021.