Coordinated by Bobby Christensen, O.D., F.A.A.O. |
Tools of the Trade: A Review
A look at the tools you need to provide
the care that patients require.
By John Smay, O.D., Midwest City, Okla.
Every profession has its own tools of the trade -- instruments that are critical to getting the job done right. For a carpenter, you might think of a hammer and saw; for a cardiologist, an EKG machine.
Covering a growing scope
For many years, the traditional tools of our trade have been lenses and prisms. But as our scope of practice has continued to expand, so has the list of tools we need to do the job right. We now routinely use various diagnostic and therapeutic drugs; nearly all offices have slit lamps, binocular indirect ophthalmoscopes (BIOs), automated visual fields, tonometers, retinal cameras and many other pieces of diagnostic equipment.
However, I think that we should also include several small medical instruments (such as punctal dilators, irrigating cannulas and Bowman's probes) in the list of tools we need to practice the full scope of primary care optometry. This month, we'll be taking a close look at these smaller, but still important, instruments.
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Jeweler's forceps and a surgical blade. |
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Tools for treating the lacrimal drainage system
Patients often present with a chief complaint of chronic epiphora, possibly caused by reflex tearing, but often a sign of an occluded lacrimal system. Dilating the punctum, probing and irrigating are indicated when you suspect an obstruction. To perform these procedures correctly, you need certain tools, including a small-gauge punctal dilator, a 23-gauge cannula, and a 0 or 00 Bowman's probe.
Before you begin, make sure that all of the instruments are sterile. As an extra precaution against infection, add a prophylactic drop of a fluoroquinolone antibiotic such as ciprofloxacin or ofloxacin to the eye.
Then, anesthetize the eye with proparacaine or a similar drop, if you need extra anesthesia. Directly apply a sterile cotton swab soaked in 4% xylocaine to the punctum for a few seconds. Next, dilate the punctum. If you're dilating the lower punctum, have the patient gaze up temporally to protect the cornea from accidental abrasion. Pull the lid away from the globe and insert the dilator gently into the puncta with a back and forth rolling motion. You can also use ciprofloxacin ointment as a lubricant on the dilator to facilitate an easier entry if needed. The dilation will temporally open the puncta to allow for irrigation and/or probing.
Alger brush, insulin needle, Davis Spud and Golf
Spud |
The next step is to determine the patency of the lacrimal system by flushing through it. The cannula should be attached to a 3-ml syringe filled with sterile saline solution. Again, have the patient look away from the area in which you're working. Insert the cannula vertically into the puncta, then rotate it so that it's approximately level with the plane of the lid margin. The vertical portion of the lacrimal canal is about 2 mm.
After the rotation, you should have no trouble inserting the cannula 8 mm to 10 mm more before you touch the wall of the lacrimal sac. Pull back slightly and gently force the saline into the lacrimal system. If the drainage system is patent, the saline should flow through easily and the patient will report tasting salt or feeling the liquid in his throat. You may dislodge a small obstruction, which you'll feel give way. If saline regurgitates from the same punctum, then the obstruction is probably before the common canaliculus. If it comes from the other punctum, then the obstruction is probably in or beyond the common canaliculus.
Perform further attempts to open a non-patent system, or to localize an obstruction, with the Bowman's probe. If repeated attempts at probing and irrigating don't remove the obstruction, then you might want to consider surgery.
3 tools for removing corneal foreign bodies
Corneal foreign body removal also constitutes a large part of many optometric practices. Fortun-ately, we can successfully remove nearly every corneal foreign body with 3 tools: a foreign body spud; a syringe and needle; and an Alger brush.
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Here you'll see the Castroviejo double-ended lacrimal dilator, Shahinian lacrimal cannula, Lacrimal Cannula-Straight, 25-gauge straight probe and Ruedemann lacrimal dilator. |
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Foreign body spuds. These tools come in several shapes and designs; some have rounded tips, some pointed, some are angled, some straight and some are slightly concave. Most spuds have slightly sharpened edges.
Spuds are most helpful for removing moderate to deeply embedded, medium- or larger-sized foreign bodies. You can use the edges to leverage the foreign body loose and scoop it out while the risk of further corneal penetration remains low. The foreign body spud is probably safer than a needle because of its relatively blunt tip; however, it's bulkier and less precise than a needle, and you may remove excess epithelium.
Syringes and needles. For removing smaller, more delicate foreign bodies, a hypodermic needle and syringe can provide a more precise means of removal. These needles are also useful for removing symptomatic conjunctival cysts and concretions.
Insulin hypodermic needles come packaged with a syringe, which you can use for easier handling and better control. You can use the sharp edges of the bevel to cut through tissue if you need to dislodge the foreign body. However, take great care not to penetrate the deeper corneal layers. Remember to approach the eye at an angle tangential to the cornea. This will lessen the risk of perforation if the patient moves unexpectedly. Use the bevel to work the foreign body loose from the sides and then lift it out whole if possible.
Alger brush. Most metallic foreign bodies that are in an eye for more than a few hours produce a surrounding rust ring. For proper healing to take place, you must remove this ring. A hand-held Alger brush works well for this task. It uses a small, battery-powered motor to spin a metal drilling burr and it is safer than stronger drills because it will stop when too much pressure is applied and therefore won't penetrate Bowman's layer.
Use the Alger brush in a sweeping or circular manner to remove rust-stained tissue and debris. Also remove any large pieces of loose epithelium to create a smoother, quicker healing defect.
A lens with many uses
The Morgan lens system is useful for treating ocular chemical injury and for removing multiple non-embedded foreign bodies. It's a large polyethelene contact lens with surgical grade silicon tubing attached to deliver fluid to the ocular surface. You can connect the tubing to an I.V. bag of lactated Ringer's or saline solution to provide a constant flow of liquid to the eye.
The Morgan lens allows for a hands-free way to flush the eye, and it prevents lid closure from interfering with the delivery of solution. First instill a drop of anesthetic, then attach the Morgan lens to the I.V. bag and start the flow, which will allow the lens to float on a fluid layer rather than rest on the cornea.
Have the patient look down and insert the lens under the upper lid, then have him look up and insert the lower portion of the lens under the lower lid. If necessary, you can tape the tubing to the patient's forehead so he won't accidentally pull the lens out. Also consider asking the patient to tilt his head sideways so you can collect used solution in a basin for disposal.
Ocular chemical burns. This type of injury is considered a true ocular emergency and you should initiate treatment procedures immediately -- even before taking visual acuity. The most important step is to thoroughly flush the eye for 30 minutes to remove the chemical. Wait a few minutes after flushing the eye and then measure the pH. Continue flushing until you get a neutral pH (7.0).
Multiple non-embedded foreign bodies. Remember to do a complete foreign body assessment before initiating treatment. Use the Morgan lens to flush the small particulate matter from the eye. Then perform a slit lamp evaluation to detect any abrasions or residual foreign bodies.
A stromal
puncture needle. |
A tool for treating RCE
The anterior stromal puncture needle is a valuable tool for treating recurrent corneal erosion (RCE). These are 25-gauge needles with an approximately 45-degree bend in the shaft of the needle and a second small bend in the bevel. The angled shaft allows you to penetrate the bevel into the anterior stroma with little danger of further penetration or perforation.
Typically with RCE, you'll see a roughened area of the corneal epithelium that may show light positive or negative stain with fluorescein dye. These areas usually correspond to the site of the original corneal defect. Options for treating RCE include artificial tears, hyperosmotic drops or ointments, epithelial debride-ment, a long-term bandage contact lens, PTK and anterior stromal puncture.
Stromal puncture is indicated for cases of RCE outside the visual axis that have failed to respond to medical treatment including hyperosmotics. The procedure involves using the stromal puncture needle to make several small punctures through the epithelium and Bowman's membrane into the anterior stroma. You can perform stromal puncture through an intact epithelium, or after epithelial debridement.
First, anesthetize the cornea with a topical anesthetic such as proparacaine. Then use the needle to place several punctures in a grid-like pattern into the anterior stroma. As these punctures heal, they'll provide a more secure base for the new epithelial growth to adhere to. After you complete the procedure, pre-scribe a topical antibiotic, a cycloplegic drop and an optional bandage contact lens. See the patient daily until the epithelium is intact.
Two tools you shouldn't be without
The last two tools on my list are a pair of jeweler's forceps and a supply of 15-degree surgical blades. These tools have several uses in the office, including removing loose foreign bodies and epilating lashes with the forceps, removing concretions and lancing superficial cysts with the surgical blade. Together, these two tools are especially useful for removing sutures or suture barbs from in and around the eye.
After sufficient wound healing has taken place for the epithelium to hold its position, you can safely remove interrupted sutures in the lids. To do this, grasp the free end of the suture with the forceps and pull the suture away from the tissue. Use the blade to cut the suture at the tissue surface. Then grasp the long end of the suture and pull it out so you don't pull the exposed suture material through the wound. After removal, treat the area with a topical antibiotic ointment.
When patients present with foreign body complaints caused by an exposed suture from a previous intraocular surgery, you can consider removing the sutures if the surgery took place 3 months ago or longer. However, if you're unsure about the wound stability for a particular procedure, then consult the patient's surgeon before you attempt to remove the suture.
To remove these exposed sutures, anesthetize the cornea with a topical anesthetic such as proparacaine and instill a drop of a topical fluoroquinolone. Then grasp the exposed suture material with the forceps and pull it away from the exposed ocular surface. Cut the suture with the surgical blade. If the suture is loose, then pull it out with the forceps. If it's only an exposed barb, then it should retract back down below the ocular surface once you make the cut. Perform a Seidel test to check for wound leaks and prescribe a topical antibiotic for 3 to 5 days to reduce the risk of infection.
Arm yourself with tools for a successful practice
This is obviously not an all-inclusive list of the tools that a primary care O.D. uses in practice, but it does represent some of the more common tools and procedures that we need from day to day. Remember: To practice quality primary care optometry, you must possess the knowledge to perform the necessary procedures, have the proper instrumentation in your office and the confidence to do what is indicated. In other words: Understand the problem, have the tools and perform the procedure.
Dr. Smay practices primary care optometry in a four-doctor group practice in Midwest City, Okla. He's a 1996 graduate of Northeastern State College of Optometry in Tahlequah, Okla. He completed an ocular pathology residency at the Western Oklahoma Eye Center.
Dr. Christensen has a partnership practice in Midwest City, Okla. He's a diplomate in the Cornea and Contact Lens Section of the American Academy of Optometry. He's also a member of National Academies of Practice.