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When the vitreous gel partially collapses, migrating forward with age and beginning its tug of war with the retina, the first signs of trouble may show up as floaters and flashers. As an ophthalmologist, your No. 1 job at this point is to determine whether a retinal tear is present. The most efficient way to achieve this is with indirect ophthalmoscopy, combined with scleral depression, which offers an increased field of view with good illumination, decreased magnification and distortion and the potential for binocularity.
Three retina surgeons shared a few tricks of the trade to make the peripheral retinal exam easier and more effective for both you and your patients.
Enhance Your Skills
Jonathan D. Walker, MD, noted that the Academy’s Preferred Practice Pattern recommends indirect ophthalmoscopy for patients with symptomatic posterior vitreous detachments.1
“I see people who feel comfortable with the contact lens [or handheld high plus lens] examination, but they don’t really tune up their skills of scleral depression,” said Dr. Walker, assistant clinical professor of ophthalmology at Indiana University in Fort Wayne. Although a contact lens exam may complement indirect ophthalmoscopy, it shouldn’t replace it, because a contact lens exam often can’t get all the way to the ora serrata, especially in a pseudophakic patient, he said.
Start with yourself. You might find it instructive to have a colleague practice scleral depression and placement of the contact lens on you, Dr. Walker said. This will give you a better sense of what it takes to elicit patient cooperation during an exam. Alternatively, he recommended practicing on a family member, who might be more forthcoming than your patients about giving you constructive feedback.
Practice, practice, practice. For those first starting out, Dr. Walker recommends practicing on people who have normal retinas. This gives you a sense of what is and isn’t normal, so you develop an almost intuitive sense of when something is wrong. “When I was a resident, I picked five patients a day to examine,” he said. “After even one week of doing that, you begin to get everything lined up and it gets easier.”
Study the classics. Dr. Walker suggested taking the time to review the Academy’s online course “Peripheral Retinal Lesions in Profile.”2 Norman E. Byer, MD, who developed the course, is “a magician when it comes to photographing the peripheral retina,” and his textbook on the peripheral retina is invaluable as well, Dr. Walker said. It has a complete set of stereo slides and can be found in most ophthalmic libraries.3
The First Priority: Comfort for All
Proper positioning is critical for both patient and physician. Getting the patient tilted well back in the examining chair allows you to look at the superior fundus without having to bend way over, said Dr. Walker. “Then you don’t need to exert a lot of axial muscle activity, which means you can focus more on your fine motor skills.”
Jennifer U. Sung, MD, a retina specialist with Pacific Eye Associates in San Francisco, also uses a drop of topical anesthetic to make the exam easier for patients. “It makes probing with the scleral depressor more tolerable, lessens sensitivity to light and keeps eyes from drying out as quickly.”
Wayne E. Fung, MD, noted that most physicians know to dilate the pupil as much as possible in advance of the exam. But some might not know to never turn the light all the way up, no matter what kind of indirect ophthalmoscope is being used, he said. Dr. Fung is a founding member of Pacific Eye Associates.
Five Top Tips
Make sure the room is dark enough for you to achieve sufficient contrast. Avoid too much ambient lighting.
Don’t begin with the brightest light. Once the patient is accustomed to the light, you can gradually turn it up to double-check a selected area.
Have a sequential system for scleral depression: Begin by looking in one quadrant, then proceed to the next.
Look at the big picture first, then magnify.
Carefully examine the region of the vitreous base, especially in aphakic or pseudophakic eyes.
Tease Out Tears, Breaks and Holes
Using a cotton-tipped applicator to do scleral depression allows you to examine from different vantage points. “As you’re moving the depressor around,” said Dr. Walker, “you can see the pathology in profile to determine if it is really a tear or irregularity of the retinal surface.” And doing this with both eyes gives you a point of comparison.
Align with the patient. You need to line everything up at all times, Dr. Walker said. Start with your pupils and the indirect ophthalmoscope, then add your arms, the patient’s pupil and the indirect lens, thus making your pupil and your depressor a straight line and using the patient’s pupil as a fulcrum.
Try first looking through the pupil without the indirect lens, Dr. Walker said. “If you gently push the depressor on the far side of the pupil, you may be able to see a change in the color as your depressor pushes the retina in. Then you know you’re lined up straight and you can put your indirect lens up.”
Go for macro and micro views. “I begin looking into the fundus with either a +28- or a +30-D lens,” said Dr. Fung. “If I want to examine with greater magnification, then I use the +20-D lens along with scleral depression.”
Another way to get a more magnified view of the peripheral retina at higher resolution is to move the patient to the slit lamp and use the Goldmann three-mirror contact lens, which you place on an anesthetized cornea, said Dr. Sung. Sometimes you need to go back and forth. Another option is to use B-scan ultrasonography, she said, especially if there is a very dense vitreous hemorrhage or the view is limited in some other way.
Go slow. When getting ready to depress, be sure to tell the patient you will be pressing lightly on the eye through the eyelid, said Dr. Fung. If you gain the patient’s confidence, you’ll make more progress.
“Usually, you don’t have to push hard to get a good indented exam,” said Dr. Walker. If you have to push a lot to see, you probably are not lined up properly. He suggested taking away the lens and reassessing the depressor’s placement. Once you visualize the site of indentation through the lens, you can work with the mechanics of moving, he said. Remember that everything you’re looking at is in reverse and you need to mentally keep the patient’s pupil as the center of rotation.
Be systematic. The most important thing is to be systematic in your approach, looking in one quadrant and then another, said Dr. Sung. “I tend to start superiorly around 12 o’clock and go all the way around the eye in a clockwise fashion.”
Dr. Fung recommended starting in the superior temporal quadrant, with the patient looking up and temporal, especially with patients 60 and older. That’s because there is a lot of eyelid present when patients direct their gaze downward toward the nose, and the tarsus in the upper eyelid is out of the way when they look up.
Dr. Fung also noted that the eyes of Asians younger than 35 or 40 are more challenging to indent. They have less eyelid tissue and it is less flaccid, so it’s more difficult to see results without pushing too hard. In addition, he emphasized the importance of depressing in the region of the vitreous base, especially in pseudophakic eyes.
Position the eye. How do you get patients to look in a particular direction? Dr. Sung suggested giving patients tactile clues, such as tapping them on the shoulder. And with those patients who can rotate their eyes rather far, be sure you’re pressing in the area of the ora serrata and not the limbus, she said.
Document changes. “In the case of a retinal detachment or a suspected tumor, it’s wise to make a drawing of what you are seeing,” said Dr. Fung. Standard forms are subdivided into the posterior pole, equator and ora serrata; universal color-coding also helps with standardization of findings.
Follow up. If a patient has a vitreous hemorrhage, Dr. Sung sees the person in a day or two for reevaluation. If the patient only has flashes and floaters, she recommends seeing the patient in four to six weeks for a repeat dilated fundus exam with scleral depression.
1 Posterior Vitreous Detachment, Retinal Breaks and Lattice Degeneration PPP. Go to www.aao.org/ppp.
2 Go to www.aao.org/one.
3 The Peripheral Retina in Profile: A Stereoscopic Atlas (Torrance, Calif.: Criterion Press, 1982).