PART 3 OF A 3-PART SERIES
Ophthalmic Technician Continuing Education

Increasing Your Clinical Value: Opportunities for Ophthalmic Technicians to Get Involved with Glaucoma Patients

By Ronald L. Gross, MD, April M. Leger, COT, and Vanessa D. Tamez, COA

Faculty/Editorial Board:

Ronald L. Gross, MD, April M. Leger, COT, and Vanessa D. Tamez, COA

Sponsors/Support:

Supported by an Independent Educational Grant from Allergan, Inc.

This course has been submitted to JCAHPO for consideration of CE credit.

This course is not sponsored by JCAHPO; only reviewed for compliance with JCAHPO standards and criteria and awarded continuing education credit accordingly; therefore, JCAHPO cannot predict the effectiveness of the program or assure its quality in substance and presentation.

The opinions expressed in this supplement to Review of Ophthalmology do not necessarily reflect the views, or imply endorsement, of the editor or publisher. Copyright 2013, Review of Ophthalmology. All rights reserved.

It is estimated that glaucoma currently affects approximately 2.2 million people in the United States¹ and this number is projected to increase to 3.3 million by 2020. Even more impressive, several studies have shown that at least 50 percent of people with glaucoma have not been diagnosed.^2-4 Furthermore, an estimated 120,000 individuals in the United States are blind from glaucoma.^5-8

Worldwide, the number of cases of glaucoma is estimated at more than 60 million, with it being the second most frequent cause of irreversible blindness, according to the World Health Organization.⁹ The disease accounts for more than 10 million doctor visits each year,¹⁰ at an estimated cost (including heath care, Social Security benefits and lost tax revenues) of more than $1.5 billion per year.¹¹

Bearing these statistics in mind, doctors have their work cut out for them in caring for glaucoma patients. That is why having a trusted, competent support staff is so important. This CE monograph will provide ophthalmic technicians with a complete look at how they fit in to the care of the glaucoma patient, starting with a comprehensive look at the disease.

GLAUCOMA 101

Glaucoma is an optic neuropathy made up of a group of diseases in which damage occurs to the optic nerve structure with a corresponding loss of function in a characteristic distribution. The optic nerve is comprised of the axons of the retinal ganglion cells that carry visual information from the eye to the brain. The fibers exit the eye posteriorly through an opening in the sclera containing small holes, the lamina cribrosa. Clinically, this is described as the optic disc.

In glaucoma, it is postulated that the damage occurs to the nerve fibers as they traverse the lamina cribrosa, resulting in retinal ganglion cell death. This results in loss of vision because the visual information originating in those areas of the retina that give rise to the axons is no longer transmitted to the brain. Clinically, the optic disc structure changes with the loss of axons, resulting in thinning of the neuroretinal rim as the optic cup size increases. This is associated with loss of the nerve fiber layer of the retina comprised of the retinal ganglion cell axons. Elevated intraocular pressure (IOP) is the largest risk factor for the development of damage, but is not necessary for diagnosis. The diagnosis of glaucoma is determined by the presence of damage with these characteristic changes. Visual field testing that measures the function of the visual system is often abnormal in a distribution corresponding to the loss of axons. In general, optic nerve changes occur before functional abnormality in the visual field is present.

Types of glaucoma. The glaucomas are categorized several ways. Most commonly, they are separated based on the anatomy of the anterior segment of the eye as those with open angles and those with angle closure. Aqueous humor is the fluid that brings nutrition to the structures in the front part of the eye and carries away waste products. Under normal circumstances, it is derived from blood and produced by the ciliary body of the eye, which secretes it into the posterior chamber, where it flows through the pupil into the anterior chamber and exits the eye through the trabecular meshwork in the angle of the eye defined by where the iris and cornea meet

In open-angle glaucomas, the aqueous gets to the trabecular meshwork, but there is increased resistance to outflow, which results in increased IOP. These are further categorized as primary open-angle glaucoma (POAG), in which there is no identifiable cause, and secondary open-angle glaucoma, in which a cause such as pseudoexfoliation, pigment dispersion or inflammation is identified. Another type of open-angle glaucoma is low-tension (or normal pressure) glaucoma, where typical glaucoma damage occurs without evidence of elevated IOP, presumably reflecting an increased susceptibility of the optic nerve to damage.

In angle-closure varieties, the aqueous cannot get to the trabecular meshwork because the iris blocks it, resulting in elevated IOP. Primary angle closure occurs due to blockage of the aqueous as it attempts to flow through the pupil, increasing pressure behind the iris and causing it to bow forward and cover the trabecular meshwork. Acute angle-closure glaucoma is a true medical emergency. It presents with a profound loss of vision associated with a very painful red eye. Secondary angle-closure glaucoma is generally caused by either the iris being pulled forward to cover the trabecular mesh-work, as occurs in neovascular glaucoma, or by the iris being pushed forward from behind, as can occur with some systemic medications such as topiramate, which is commonly used to treat seizures.

Risk factors. Risk factors for developing POAG include elevated IOP, race, age, family history of glaucoma, corticosteroid use and thin central corneal thickness (CCT).

Elevated IOP—This is the greatest risk factor and the one that can be directly treated. The Ocular Hypertension Treatment Study (OHTS) found a 10 percent increased risk of developing glaucoma for each mmHg above 24 mmHg.^12,13 Additionally, the higher the IOP, the greater the chance that glaucoma will be present.¹⁴

Race—POAG is about three times more common in blacks and Hispan-ics than whites, with blindness from glaucoma six times more common and visual disability¹⁵ times more common in blacks than whites.^5-8

Age—Based on OHTS, there is a 22 percent increased risk for developing glaucoma with each additional decade of age.^12,13 POAG is six times more likely develop in those over the age of 60 years. In general, it is suggested that blacks and Hispanics at risk should be screened for glaucoma beginning at age 40; whites beginning at age 50.

Family history—Although OHTS did not demonstrate an increased risk of developing POAG with a positive family history, several other studies have shown a positive family history of glaucoma to be a risk factor for glaucoma.^15,16

Corticosteroid Use—The use of corticosteroids can result in an increase in IOP. This is most common with intense topical use, with 15 percent of normal patients being steroid responders. It can also occur with inhaled and oral steroid use. The increase in IOP usually resolves with discontinuation of the steroids.

Thin CCT—Thinner corneas effect the measurement of IOP with Goldmann tonometry, resulting in a measurement lower than the actual IOP. Conversely, a thicker cornea results in an overestimation of IOP. OHTS demonstrated a greater risk for patients with thinner (<555 µm) CCT than could be explained by underestimation of actual IOP alone.^12,13

In low-tension glaucoma, other risk factors, primarily those that affect systemic circulation—such as diastolic perfusion pressure—have been identified. Diastolic perfusion pressure is the difference between diastolic blood pressure and IOP. A value of <50 mmHg confers increased risk of glaucoma. Other findings associated with decreased circulation include cardiac arrhythmias, low blood pressure and vasospastic diseases such as migraines.

Increased risk for angle-closure glaucomas include race, with whites and Asians at highest risk. In Asians, up to 50 percent of glaucoma is angle closure, compared to only between five percent and 10 percent in whites.¹⁷ Increasing age is a risk factor for primary angle closure due to the increased size of the crystalline lens increasing the papillary block.¹⁷ Hyperopia and the smaller globe of the female gender and whites increase the risk of angle closure.

Eye trauma can result in secondary open-angle or angle-closure glaucoma. Additionally, underlying causes including diabetes, retinal vein occlusion, intraocular inflammation, autoimmune diseases, developmental eye abnormalities, pseudoexfoliation and pigment-dispersion increase glaucoma risk.

PATIENT CONSIDERATIONS

It is important to realize the impact that glaucoma has on patients. Even mild visual field loss is associated with a far lower patient-reported quality of life.¹⁸ Visual field loss of 4 dB to 5 dB in the better or worse eye corresponds to a clinically meaningful difference in vision-related quality of life.¹⁸ Furthermore, glaucoma patients are three times more likely to fall compared to control subjects and five times more likely to be involved in an auto accident compared to control subjects.^19-22 Not surprisingly, those with bilateral glaucoma are most significantly impacted.²³

It should then make sense that education is a vital component of the care of the glaucoma patient. For glaucoma suspects (patients at increased risk of developing glaucoma compared to normal), the factors affecting risk must be first identified and then used to estimate each individual's likelihood of developing glaucoma. At that point, a discussion with the patient is key in allowing him to play an active role in evaluating the risk-benefit ratio of possible treatments and deciding on the treatment plan. This is especially important for patients with POAG, as their treatment plan and regimen requires their participation.

POAG is usually asymptomatic without any immediate perceived benefit of therapy. Patients don't see or feel better and the treatment itself has side effects. Thus, it is very important that patients be educated about their disease so they understand the importance of being adherent to their treatment regimen. They are the ones instilling the drops every day, and sometimes they have to deal with more than one type of medication and more than once daily. It's not easy for patents to maintain this over the long term.

Showing patients how to instill an eye drop may well be invaluable— particularly for those who have never before used an eye drop. In addition to personal instruction, a handout describing the proper technique for instilling eye drops is also useful. In follow-up, consider asking patients to instill an artificial tear to confirm correct technique.

Finally, when surgery is imminent, make sure the patient and their support group understand the risks and benefits of treatment, as well as the procedure itself so that they will have proper expectations. Also keep in mind that postoperative instruction plays a key role in maximizing surgical success.

RESPONSIBILITIES OF THE OPHTHALMIC TECHNICIAN

The technician plays a key role in all aspects of the care process. As the first person to greet the patient in the clinic, a big part of the technician's job is to make a good impression. Being able to demonstrate effective communication and clinical skills will garner the patient's confidence in the doctor and the practice. The more knowledgeable the technician is about glaucoma, the greater their ability to accomplish this vital task.

Taking a thorough history is crucial for the new patient glaucoma exam. The tech should gather as much information as possible so the doctor has a complete a picture of the patient's understanding of their disease and previous treatment. This will ensure an efficient and successful visit and allow the doctor to select the most effective treatment plan for the patient. During the history, ask the patient about current treatments, such as eye drops, as well as past treatments, including lasers, surgeries and eye drops. Knowing which drops were tried and why they were stopped can save the doctor and the patient precious time, as they will not have to repeat that treatment.

The glaucoma technician should also inquire about family history of glaucoma, as this can be a risk factor for the disease.^15,16 A thorough medical history and list of all current medications—not just those for glaucoma—should be gathered. Systemic diseases, such as diabetes and hypertension, can be contributing factors to certain types of glaucoma, and medications used to treat such conditions (e.g., steroids) can raise IOP in some patients.

Medication allergies, such as an intolerance to sulfa drugs, are another valuable piece of information to collect for the doctor. Having information about all medical conditions and medications gives the doctor a complete picture of a patient and is key in forming an adequate treatment plan for the patient.

In the follow-up exam, an abbreviated assessment is needed and should focus on changes in the patient's medical and ocular status since his last visit. It is often necessary to specifically ask the patient about their visual function and medication use because often, when simply asked how they are doing, patients will respond, "fine," or "nothing has changed."

A technician can get a feel for how compliant a patient will be with treatment by specifically asking which drops he uses, how often and at what time he last used them. Patients tend to confide in technicians more so than doctors about forgetting to use their drops. Make sure that patients understand how to properly instill eye drops, how to space doses (such as every 12 hours for b.i.d. doses) and that they should wait at least five to 10 minutes between doses of multiple different drops. If you suspect that a patient is not using his drops appropriately, consider the barriers to drop compliance. Is the regimen too complicated with too many drops instilled too many times a day? Is the problem with the patient remembering to use the drops? Is the patient physically unable to get the drop in his eye? If these or other reasons are present, adjustments will need to be made. Often, involving family members or caregivers to remind patients or actually instill the drops may be necessary. It's also a good idea to inform the doctor of the issue so the regimen can be simplified, if necessary, or reinforce the need for help at home for the patient.

Once the doctor is through with the exam, the technician is available to answer the patient's questions about his treatment. Once the patient leaves, they may call the office later with questions about surgical treatment recommended by the doctor or clarification on directions for medication. For this reason, among others, glaucoma technicians should be very familiar with all of the surgical procedures performed by the physician and be able to answer any questions about the preoperative assessment, actual procedure, recovery and postoperative medications and instructions. They should also be knowledgeable about the different medications prescribed for glaucoma and their potential side effects. Equally important is the ability to realize when the doctor should answer the patient's question. This will vary depending on the technician and the doctor. Effective communication will facilitate the appropriate management of these issues.

Follow-up care is especially important with glaucoma patients to minimize further progression of the disease and the potential for permanent vision loss. Because these patients must be monitored closely—and usually for the rest of their lives—ophthalmic technicians can get to know them very well. And when patients see the same technicians every time they come into the office, they learn to trust them and rely on them for help with everything from medication refills to explanations about surgical procedures recommended by the physician.

Glaucoma technicians can learn from their doctor how to answer common questions about surgery, medication doses and the types of testing commonly needed. Instructing a patient on how to instill eye drops is something that occurs frequently in a glaucoma practice. The technician can help the patient find the most effective way to get medication in his eye. Something so simple can make the difference in whether or not a patient is actually using his medication as prescribed. It is also helpful for glaucoma technicians to take part in the discussions of patient expectations when surgery is planned. They can ensure that patients understand that their surgery will likely not improve or restore vision that has been lost, but will simply help to prevent further vision loss. And when technicians get involved in these kinds of discussions, it can save the doctor a considerable amount of time.

Experienced technicians are invaluable to doctors in almost all aspects of the care of glaucoma patients. Delegation of tasks such as answering questions about medications or surgery, ordering diagnostic tests and handling medication refills to technicians frees up the doctor to spend more time with the patient. Technicians who understand glaucoma can assist in educating patients about the disease and how important compliance is to their treatment. The greater the knowledge of the technician, the greater an asset they are to the practice. Let's now take a look at how they can lend a hand in the area of diagnosis.

THE DIAGNOSTIC PROCESS

The diagnosis of glaucoma is dependent on the results of the clinical examination and testing. Based on the history that the technician gathered from the patient, the doctor will look for evidence of secondary forms of glaucoma.

Gonioscopy is required to dif ferentiate open-angle from angle closure. Gonioscopy allows the visualization of the angle to determine whether it is open, narrow or closed. The doctor performs this, but the technician can facilitate the procedure and allay some of the patient's concerns by informing them that it is a routine procedure and is important.

Measurement of IOP is tonometry and in many practices, the technician is responsible for this task. There are two methods used for IOP measurement in most glaucoma practices: Goldmann ap-planation tonometry and Tono-Pen (Reichert Technologies). Historically considered by most to be the more accurate method, Goldmann applanation tonometry is generally the preferred method. Occasionally, when corneal scarring is present, after corneal transplant surgery, or when patients are physically unable to sit at the slit lamp, then the Tono-Pen is appropriate.

For Goldmann applanation tonometry, technicians first instill an eye drop composed of fluorescein and an anesthetic to both eyes. Next, instruct the patient to place his chin on the chin rest of the slit lamp, with his forehead touching the plastic band at the top. Then, place a clean tip (disinfected with either a 10 percent bleach solution rinsed off, or with alcohol and dried) on the tonometer's arm.

Once the patient is positioned, the tech slowly moves the tonometer toward the eye, looking first from the side, and then through the slit lamp oculars until it gently touches the cornea. Be sure not to apply too much pressure. This can be observed through the oculars by the mires suddenly getting very large, and can be remedied by simply moving back slightly, yet still maintaining contact with the eye. Once the two semicircular mires are seen, the tech adjusts the tension dial on the side of the tonometer until they are just touching each other on the inside of the semicircular images.

In the case of "pulsing" mires, or mires that appear to move in and out with the pulse, line them up so that there is equal distance on either side of them as they move. Mires that are not equal in size, or that are not centered indicate poor positioning. Slight adjustment with the slit lamp joystick up, down or to either side will remedy this. After observing proper alignment of the mires, move the tonometer off of the eye and record the IOP measurement from the dial. The dial is numbered with single numbers from one to six and four hash marks between the numbers. Each number represents 10 mmHg and each hash mark represents 2 mmHg. For instance, the two represents 20 mmHg and two hash marks after the two represents 24 mmHg. Readings between hash marks are odd numbers. Repeat these steps for the other eye and record that IOP measurement as well. In patients who have corneal scarring from injury, disease or previous surgery, the mires may appear distorted with applanation and it may be difficult to assess the IOP measurement. In these instances, use a Tono-Pen.

For the Tono-Pen, the technician instills a drop of anesthetic only in both eyes. Then, the calibration of the instrument is verified, and if a "good" reading is found, the tech should ask the patient to look straight ahead. Touch the Tono-Pen gently to the central cornea and you will hear a short beep. Continue to touch the cornea and until you hear a long beep, which indicates that a reading has been obtained. Verify that the accuracy of the reading is less than five percent by checking the indicator line next to the reading. If it shows that the accuracy is greater than five percent, then repeat the measurement until it shows less a than five percent accuracy. The Tono-Pen can be useful for measuring IOP in young children because it can be performed while sitting in a chair, lying down or even with the child in a parent's lap. This device can also be helpful for patients who have difficulty keeping their eyes open for applanation because they do not have to open them as wide for the Tono-Pen.

Tonometry is an invaluable skill for any technician to possess, especially in a glaucoma practice, though it does take some time and practice to master. Doctors or experienced technicians should "check-behind" technicians who are new to the practice to be sure the measurements are accurate. Sometimes helpful tips are needed to correct common mistakes in technique. For instance, if an inexperienced technician is consistently getting readings higher than the doctor or another more experienced technician, they should be reminded not to put pressure on the eye while holding the lid. Also, it should be confirmed that the new technician has a clear understanding of what the mires are supposed to look like when aligned properly. Tonometry is one of the most important components of the glaucoma exam. Every IOP reading at every visit is important, as it helps the doctor make decisions about care and treatment for every patient seen.

An additional part of the examination is a critical evaluation of the optic disc, which generally requires pupillary dilation. The technician should identify patients requiring dilation and make sure they are adequately dilated prior to the doctor's examination. Patients at risk or who have angle-closure glaucoma should not be dilated until the doctor evaluates them. If you feel confident with your slit lamp examination skills, then you can identify a shallow anterior chamber consistent with angle closure. It is extremely important that the technician identify these patients to minimize the inappropriate dilation that could precipitate an angle-closure attack. Reversal of dilation pharmacologically may also be desirable for some patients.

Testing is another a key component of glaucoma diagnosis and includes both functional and structural evaluation of the optic nerve and nerve fiber layer.

Functional testing involves performing visual fields, generally using the Humphrey Field Analyzer (Carl Zeiss Meditec Inc.) Other devices, such as the Octopus perimeter (Haag-Streit) can perform similar evaluation, although the nomenclature may vary. The technician plays a key role in ensuring the best quality of the test performed. The first step is to be sure that the right test is being performed. There are clinical situations where alternative testing strategies to the SITA Standard 24-2 test are appropriate, although this is the most desirable test for patients where glaucoma is the primary consideration. In patients with severe glaucomatous visual field loss, a central 10-2 field may be desirable. If diminished visual acuity is present, a size V stimulus—rather than the standard size III—may be chosen. Note: a SITA FAST strategy may be better if only screening is needed.

The next step is to be sure that the best-corrected visual acuity with appropriate near add for age is used for the test. Visual fields measure retinal sensitivity. To get the best quality test, the best-corrected vision possible should be used. The patient should be positioned correctly and instructed so they understand the test and what they are supposed to do. Some patients, particularly those experiencing it for their first time, need intermittent observation and reinforcement during the test to be sure they are performing it appropriately. Sometimes, reminding the patient, or even stopping the test and reinstructing them, is needed. Once completed, proper comparison algorithms should be performed— if tests were conducted previously. Finally, be sure to save the test in the proper format.

Structural evaluation involves evaluation and measurement of the optic disc and/or the retinal nerve fiber layer. Several technologies measure different anatomic parameters. As the technician, confirm that the correct test is being performed and that the quality of the scan is optimized. A thorough understanding of how to perform the testing is needed to accomplish this. Again, comparisons to previous scans, when available, are appropriate.

These tests, when combined with the clinical examination, provide the components that need to be synthesized to determine the presence of glaucoma damage, thus resulting in a proper diagnosis. Because treatment of different types of glaucoma is often much different, accurate diagnosis is key. Next, we will delve into more detail related to glaucoma treatment.

MANAGING THE GLAUCOMA PATIENT

Over the past two decades, many excellent clinical studies have shown the benefit of lowering IOP in decreasing the risk of developing glaucoma or minimizing the risk of glaucoma progression.^{12,13, 26-28} OHTS demonstrated that lowering IOP by 20 percent in patients with elevated IOP of 24 mmHg to 32 mmHg decreased the risk of their developing glaucoma in five years by about 50 percent—from 9.5 percent in the observation group to 4.4 percent in the treated group.^12,13 A similar, although slightly smaller, benefit was demonstrated in African Americans when analyzed separately. Analysis of the data showed that for each 1 mmHg higher baseline IOP, the risk of developing glaucoma increased by 10 percent.^12,13

The Early Manifest Glaucoma Trial (EMGT) compared treatment to observation in patients with open-angle glaucoma.²⁴ Treatment was betaxolol (Betoptic S, Alcon) and argon laser trabeculoplasty. There was no specific target IOP. Although progression was relatively common in both groups, possibly due to a very sensitive analysis, treatment was beneficial compared to observation in reducing progression from 62 percent to 45 percent. There was also a delayed onset of progression in the treated group from 48 to 66 months. Because there was no target IOP, when the magnitude of IOP lowering overall was analyzed, it was found that each 1 mmHg of IOP lowering reduced risk of progression by 10 percent.²⁵

In the Collaborative Normal Tension Glaucoma Study (CNTGS), the question of whether lowering IOP in glaucoma patients with IOP in the "normal" range was of benefit was examined.^26-28 Again, the eyes treated with a 30 percent reduction in IOP target had a three-fold reduced risk of progression—from 36 percent in the observation group to 12 percent in the treated group. Thus, in ocular hypertension, open-angle glaucoma and normal-tension glaucoma, lowering IOP is effective. That is not to say that lowering IOP will always prevent progression, but there is no question that lowering IOP decreases the risk substantially, and most experts feel that the more effectively the IOP is lowered, the less the risk of progression. Furthermore, CNTGS identified predictive factors for progression. Progression was more common in women, patients with migraines and the presence of disc hemorrhages. Also, progression occurred more quickly in women, especially those with migraines. This is another point to keep in mind when taking a patient's history.

The impact of variability of IOP over time is more controversial. It appears that the more severe the damage and the more aggressive the therapy, the greater the importance of IOP variability. Thus, treatment of glaucoma always includes lowering of IOP. This can be accomplished with medications, laser or incisional surgery and each has its advantages and disadvantages. It is vital to individualize therapy based to these characteristics for each patient's situation. The recently published Low Tension Glaucoma Treatment Study (LoGTS) used visual field outcomes rather than IOP alone to quantify treatment efficacy.^29,30 This brings up the possibility of using the disease state itself, rather than the surrogate IOP as the measure. In this double-masked, multi-center clinical trial, patients were randomized to either brimonidine tartrate 0.2% and timolol maleate 0.5%. It was found that low-pressure glaucoma patients treated with brimonidine who do not develop ocular allergy are less likely to have field progression than patients treated with timolol.

Special considerations. Congenital or developmental glaucoma is generally definitively treated surgically. Typical medications tend not to effectively lower IOP in these cases and because of the smaller size of the patients, side effects may be more profound, particularly with beta-blockers and alpha-agonists. Angle surgery (goniotomy, trabecu-lotomy) followed by tube shunts is often necessary.

Angle closure also has special considerations. A narrow angle is when, on gonioscopy there are no angle structures visible, but also no peripheral anterior synechiae (PAS, permanent adhesions between the iris and angle structures). This condition may require a peripheral iridotomy (PI). If even a single PAS is present, angle closure should be treated. Historically, a laser PI was the accepted treatment, but increasingly lens extraction has been advocated in treating papillary block. Both options relieve the resistance to aqueous flow at the pupil. If glaucoma damage is present, treatment similar to open-angle glaucoma is instituted, if needed, once the cause of the angle closure is addressed.

Medical treatment. Historically, medications have been used first line to lower IOP (see table). Over the past 20 years, there are many more choices with improved risk-benefit ratios available. In most instances of open-angle glaucoma, prostaglandin analogs (PGAs) are the first medica tion used because of their excellent efficacy and systemic side effect profile, as well as their once daily dosage. Several members of this class are available, including latanoprost 0.005% (Xalatan, Pfizer), bimatoprost 0.01% and 0.03% (Lumigan, Allergan), travoprost 0.004% (Travatan Z, Alcon) and tafluprost ophthalmic solution 0.0015% (Zioptan, Merck). There appear to be some differences in efficacy and side effect profile among the agents. In general, they all reduce IOP by about 30 percent when effective and the most common side effect is conjunctival hyperemia. Additional ocular effects include increased iris pigmentation (permanent), increased periocular skin pigmentation (reversible), loss of orbital fat and increased eyelash growth. In rare cases, PGAs may exacerbate intraocular inflammation (iritis, uveitis), cystoid macular edema (CME) and herpes infection in predisposed eyes.

It is most desirable to use a single medication if possible, but multiple medications are often necessary based on the target IOP and the patient's response to therapy. However, the efficacy of a drug in lowering IOP second line is generally less than when used as first-line therapy. The efficacy of the drug may be different in additive therapy than when it is used alone.

Beta-blockers such as timolol maleate ophthalmic solution 0.5% (Istalol, ISTA Pharmaceuticals), betaxolol HCl 0.25% and 0.5% (Betoptic S, Alcon Inc.), timolol ma-leate ophthalmic gel forming solution 0.25% and 0.5% (Timoptic-XE, Merck & Co. Inc.) are most commonly added to PGAs. There is some question as to how effective that addition is in lowering IOP. In fact, the fixed combinations of PGAs and timolol are not available in the United States as the addition of timolol could not consistently provide an additional 2 mmHg IOP reduction compared to the PGA alone. That is not to say that the combination is not useful in some cases, but there should be realistic expectations. When considering or using beta-blockers, it is necessary to assess the patient's medical status at essentially every visit. These drops can exacerbate asthma, lower heart rate, decrease blood pressure, make depression worse and may be less effective in lowering IOP if started in a patient using oral beta-blockers.

Because a patient's medical status may change over time, the technician asking about these conditions in appropriate patients is invaluable in identifying appropriate candidates as well as making sure treated patients are not experiencing untoward side effects.

Alpha agonists such as brimonidine tartrate 0.1% and 0.15% (Alphagan P, Allergan Inc.) are also useful, most commonly in additive therapy. The primary barrier to the use of this class is ocular allergic response, which appears to be a dose-related problem. The greater the concentration of drug and the greater the frequency of use, the greater is the risk of allergic response. Allergy manifests as redness and itching, often with periocular skin changes. Other potential side effects include dry mouth and somnolence. This class should not be used in small children because they can cause blood pressure problems and sleepiness. They are FDA approved to be used t.i.d., but are often used b.i.d., particularly if they are not the only agent used.

Topical carbonic anhydrase inhibitors (CAIs), such as dorzolamide HCl 2% (Trusopt, Merck & Co. Inc.) and brinzolamide ophthalmic suspension 1% (Azopt, Alcon Inc.) are also used to treat glaucoma. They are much safer than the oral CAIs, with the primary side effect being taste alteration, particularly with carbonated drinks. They are derivatives of sulfonamides, so allergy to this class may limit use. As with alpha agonists, CAIs are approved for t.i.d. use, but are commonly used b.i.d. Oral CAIs including methazolamide (Neptazane, Fera Pharmaceuticals) and acetazolamide (Diamox Sequels, Teva Pharmaceuticals) may be poorly tolerated in up to half of patients using them. Because of their severe systemic side effects, including low blood counts, kidney stones, tingling and malaise, their use is usually restricted to short-term treatment of severe glaucoma.

Fixed combinations of timolol and brimonidine or dorzolamide (Combigan [Allergan], Cosopt [Merck]) are also available. The advantages of fixed combinations include greater ability to lower IOP than either single component alone, with the attendant presumption of improved adherence because they only have to put in one drop instead of two. The concern, though, is that the side effects of both medications are present and should be assessed to ensure that the patient is getting benefit from both components to justify the risk profile.

Currently, the presence of generic medications is a reality in the medical treatment of most diseases, including glaucoma. All classes of agents used to lower IOP have at least one generic available. In general, the advantage of generic medications is the reduced cost to the patient, and possibly to the health care system. However, the use of generics does complicate the care of glaucoma patients. Patients ask whether the generic version they are using is as good as the branded agent. Unfortunately, for the most part, no studies are available that answer this question. There is no requirement by the FDA that clinical data be performed prior to approval of generic ophthalmic agents. The composition of the generic drops may vary from the branded agent, and may vary between different generics as well. This also may result in variable apparent safety and efficacy between different generic formulations of the same active ingredient. Clinically, this may complicate therapy in that the specific generic the patient is using may change over time based on the one supplied by their plan, further affecting treatment.

For patients either currently being treated with glaucoma medications or for whom treatment is being considered, there are some very important technician responsibilities that can greatly help the doctor. Before the new patient actually arrives, reach out and ask that they bring with them a list of current systemic and ocular medications as well as what ocular medications have been used in the past. If this is not possible, then the technician should obtain as much of this information as possible at the initial visit. Systemic medications may suggest systemic diseases. It is important to ask specifically about a history of CME, uveitis, ocular herpes, high or low blood pressure, asthma, depression, sulfa allergy or abnormal mentation to identify potential contraindications to medication use.

It is also important at follow-up exams to confirm that nothing has changed since their last examination with respect to these issues.

An accurate documentation of what the patient is supposed to be doing, as well as what he is actually doing is needed. Is he actually taking his drops if he hasn't needed a new prescription for two years? If she can't remember what medications she is supposed to use or when she last used them, it is possible that her therapy is inadequate. Recruiting a family member or caregiver to aid in this instance can make all the difference in the effective treatment of this patient.

Laser treatment. Laser is also an important tool in the management of both open-angle and angle-closure glaucoma. Laser peripheral iridotomy is a key tool in the treatment of angle-closure glaucoma. It is used to alleviate papillary block by making a microscopic hole in the iris to allow aqueous to flow from the posterior chamber into the anterior chamber without having to go through the pupil. This enables equalization of pressure in the two areas, allowing the iris to move posteriorly, opening the angle. Many practitioners instill a miotic such as pilocarpine to constrict the pupil and thin the iris to make the procedure easier.

Laser trabeculoplasty—argon or selective—is used to treat the natural drain of the eye, the trabecular meshwork to improve aqueous outflow, and lower IOP. It can only be performed in eyes with open angles and the expectation of effect is about a 25 percent reduction in IOP in up to 80 percent of patients with a duration of effect of two to five years.

It can be performed at any stage of treatment: before the use of medications, at any stage in medical therapy, or even following filtration surgery.

Both argon and selective laser trabeculoplasty can be performed either in the office or a laser suite. Again, the ophthalmic technician can lend a hand in ensuring that the patient understands the procedure and obtains his consent. The tech can also instill preoperative drops and obtain a preoperative IOP for comparison after the laser therapy. The use of an alpha-agonist can be used to minimize the postoperative IOP spike that can occur, which suggests that checking the IOP an hour after the laser treatment may identify any rise in IOP. Before letting the patient leave, proper instructions and warnings should be provided. And, although few problems usually occur, any marked change in vision or pain should be reported. Finally, the technician should reinforce instructions on how to use drops postoperatively.

Filtration surgery, mostly involving trabeculectomy or tube shunts, involve making a new drainage pathway for the eye. These require a procedure in an operating room and thus have substantial risks associated with them.

Trabeculectomy involves making a hole that connects the anterior chamber to the subconjunctival space that results in the formation of a bleb that allows reabsorption of the aqueous and lowering of IOP.

Tube shunts are silicone tubes that are implanted to allow aqueous to flow posteriorly to a reservoir that is encased by the orbital tissues. This envelope surface acts as the absorptive surface.

Once the decision to perform filtration surgery is made, the technician may play a role in making sure that the patient understands the risks and benefits of the procedure and in the scheduling of the procedure, including the logistics and impact of the procedure on the patient's life.

At the preoperative visit, the ophthalmic technician may participate in collecting data for the history and physical examination and informed consent. Because patients commonly have concerns during the perioperative period, the technician plays a key role in answering their questions. And as with knowledge of glaucoma in general, the more familiar the technician is with the potential pitfalls of both trabeculectomy and tube shunts, the better they can function.

COOPERATION IS KEY

In today's busy ophthalmology practices, it is essential for glaucoma physicians to delegate certain tasks to ophthalmic technicians. The technician's job is to anticipate what the doctor wants and needs and to enhance the healthcare experience of every patient who enters the practice. The more the doctor can rely on these key staff members to know what he needs to treat his patients, the more time he will have to spend on patient care. Working together as a team, the doctor and technician can provide a seamless, pleasant experience for the glaucoma patient.

As with many things in life, we cannot perform to the best of our abilities alone. That is certainly the case in the care of the glaucoma patient. The ophthalmic technician's behavior and actions directly impact the quality of the visit and the overall care of patients. They supply the doctor with the foundation of information upon which clinical decisions are built. The better the quality of the information, the stronger the foundation and the better the structure. Likewise, the more the technician is integrated into the care process, and the more they understand about glaucoma, the more effectively they can function to the benefit of all.

Dr. Gross is professor of Ophthalmology and Clifton R. McMichael Chair of Ophthalmology at Baylor College of Medicine. He is board certified, with special interests in glaucoma.

Ms. Leger is currently a tech and clinical research coordinator in the glaucoma clinic at Baylor College of Medicine, where she has worked for 13 years.

Ms. Tamez has an Associates of Applied Science degree in Vision Care from San Jacinto College. She has worked in the glaucoma clinic at Bay-lor College of Medicine for four years.

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