Meeting the demands of diabetes
There are 8 million reasons we put together the following articles on diabetes. Eight million diabetics in the United States show signs of diabetic retinal disease, and they are turning to you for help.
Diabetics comprise a population at special risk and of special interest to primary care optometrists, but it is a population that makes demands across the health care continuum. In this feature, Staff Writer Susan Biro presents interviews with experts on the optometrist's role in managing diabetic patients including managing refractive error shift, conducting blood glucose testing and helping these patients in a managed care environment. On page 20 we present the American Optometric Association's guidelines on staging diabetic retinopathy. And throughout the feature we intersperse the true stories of actual diabetes patients provided by Correspondent Henry Singer.
Our own staff has worked for months in preparing this feature. We hope you will celebrate with us the significant triumphs that optometry can claim in this area while confronting the future challenges that remain.
— Joseph Hoffman
-- John F. Amos, OD, is professor and chairman, Department of Optometry, and Director of the Professional Program at the School of Optometry, University of Alabama in Birmingham (UAB). He served as chief of optometry services in the Diabetes Research and Education Hospital at UAB from 1972 to 1976. He is currently chair, Clinical Care Center, of the American Optometric Association (AOA). Dr. Amos was named the AOA's National Optometrist of the Year in 1994. He may be contacted at School of Optometry, University of Alabama at Birmingham, 1716 University Blvd., Birmingham, AL 35294; (205) 934-0366; fax: (205) 934-6758.
-- Jerry D. Cavallerano, OD, PhD, is a staff optometrist and assistant to the director at the Beetham Eye Institute of the Joslin Diabetes Center, Boston, and an associate professor of optometry at the New England College of Optometry. He has served as Visual Function Examiner for the National Eye Institute's Early Treatment Diabetic Retinopathy Study, Diabetes Control and Complications Trial, and Sorbinil Retinopathy Trial. He is also a member of the Advisory Board for the Massachusetts Diabetes Control Program. He may be contacted at Joslin Diabetes Center, One Joslin Place, Boston, MA 02215; (617) 732-2400; fax: (617) 732-2545.
-- Michael R. Duenas, OD, practices in Chattahoochee, Fla., and is chairman of the American Optometric Association's Public Health and Disease Prevention Committee. He is a consulting physician at Florida State Hospital and a visiting faculty member at Florida A&M University. He was recently honored as the first optometrist appointed by a presidential administration to the Translation Advisory Committee of the Center for Disease Control and Prevention for the Division of Diabetes Translation. He may be contacted at P.O. Box 67, Chattahoochee, FL 32324; (904) 663-4019; fax: (850) 663-4010; e-mail: Duenasruhl@aol.com.
Primary Care Optometry News: Do you feel that most optometrists actively participate in managing their diabetic patients?
John F. Amos, OD: I feel most contemporary optometrists actively and appropriately manage their diabetic patients. By that, I mean they dilate the pupil for appropriate examination.
There may be some who refer at the first sign of retinal involvement, but I think depending on the stage of the retinopathy that is not necessary and doesn't make for the best use of the optometrist's abilities as the patient's primary eye care provider. What is essential, however, is that the optometrist be prepared to dilate the pupil and carefully examine the retina, particularly the macular area, for early signs of diabetic retinopathy.
The presence of diabetic retinopathy should be photo documented where it's necessary and, above all, the optometrist needs to be familiar with the various stages of nonproliferative and proliferative diabetic retinopathy as contained in the American Optometric Association's (AOA's) clinical practice guidelines.
Jerry D. Cavallerano, OD, PhD: I think it is important to remember that even if an optometrist identifies a patient with diabetic retinopathy and consults or refers that patient to a retinal specialist or ophthalmologist who is managing diabetic retinopathy, that's actively managing a patient.
Michael R. Duenas, OD: Yes, we are managing patients with diabetes mellitus, and the word "management" is critical. We're doing more than just monitoring for complications; we're a member of a team. We're telling the patient whether his or her current medications are properly working to prevent further complications and we're measuring blood sugars and ordering hemoglobin A1Cs. I use a management form to recommend changes in care for the general practitioner, internist or endocrinologist treating the patient for diabetes. I fill it out in front of the patient, and it reinforces to the patient that I'm part of the team and interested enough to communicate my findings to other practitioners.
New ADA guidelines
However, in a broader text, diabetes is critical because there's a war on diabetes and optometry is on the front line. I serve on the Technical Advisory Committee for the Centers for Disease Control and Prevention, and from that vantage point I can give you an idea of what this is about politically, as politicians are realizing the importance of diabetes and the cost to society, which is now estimated at $105 billion per year. For instance, the division I serve received $26 million in funding for fiscal year 1997. For fiscal year 1998, the division will get at least a $13 million increase.
Congress also appropriated $150 million - $30 million a year for 5 years - specifically targeted to diabetes in Native Americans, and $150 million for the prevention and cure of type 1 diabetes.
So, in just a short period of time, diabetes is on the front burner, and optometry is positioned very well to alleviate a substantial amount of the burden of this disease, namely blindness. I look at it as both an opportunity and a responsibility. As a profession, we should put as our highest priority the need to eliminate diabetes as the leading cause of blindness.
The new American Diabetes Association (ADA) guidelines have just come out, and everything has changed in the past several months. For example, they have modified the classification of diabetes and lowered the blood sugar levels necessary to classify a patient with diabetes. Before the change, the fasting blood sugar cut-off was 140 mg/dL; it has now been lowered to 126 mg/dL. That means if you have a fasting blood sugar of 126 or greater on two occasions, you have diabetes. Also, the oral glucose tolerance test has been eliminated.
This new classification for type 2 diabetes will increase the number of patients with diabetes almost overnight, which offers additional challenges to our profession.
On a national basis, there is an effort called the National Diabetes Education Program to alert citizens about the importance of diabetes. It's an effort between the CDC and the National Institutes of Health to let every person in the country know that diabetes is a serious disease with important consequences if it remains undetected or uncontrolled. Within the next few years, it will be common knowledge to everyone that their fasting blood sugar should be below 126 mg/dL.
PCON: Among the earliest ocular indicators of diabetes is refractive error shift. Is there a consensus regarding the direction of prescription shift?
Dr. Cavallerano: I agree that one of the early symptoms a patient may experience is blurred vision, which we may measure as a refractive shift, although we can have somebody with retinal changes and undiagnosed diabetes who is not experiencing refractive shifts or alterations in vision.
Concerning the direction of the shift, my clinical experience has been that with higher blood sugar levels, I am more likely to find myopic shift. There is documentation on either side of the issue, but I see 15 to 20 patients with diabetes 5 days a week, all year long. More likely than not, if a patient tells me his or her blood sugar has been elevated I will find him or her more myopic.
Dr. Amos: In general, I agree with the concept that the refractive error shift is an early sign related to diabetes. However, in my experience, it is not a consistent finding because not every diabetic who is undiagnosed or poorly controlled experiences a refractive error change. My rule of thumb is that any relative sudden shift in refractive error between 1 D to 3 D of either a myopic or hyperopic nature should be viewed with some suspicion on the part of the clinician. In my experience, the myopic shift is more common than the hyperopic.
PCON: With what magnitude of shift do you suspect diabetes? And once a diagnosis of diabetes has been made and treatment has been initiated, how long do you wait before prescribing new lenses?
Dr. Cavallerano: Any refractive change not consistent with a patient's age or circumstances will make me suspicious. If I have a 40-year-old person who comes in and is suddenly 2 D or 3 D nearsighted, I am very suspicious. If I have a 16-year-old who suddenly is 1 D or 2 D more nearsighted, I may not be quite as suspicious.
Once a patient has been diagnosed with diabetes and treatment has been initiated, I normally wait 4 to 6 weeks after the blood sugars have been reasonably stabilized before I write a final prescription. I may write a prescription prior to that if a person is desperate. For example, not too long ago, I had two patients with newly diagnosed diabetes in the same week who had hyperopic shifts, and I wound up giving them over-the-counter reading glasses to carry them over until they stabilized, at which time they didn't require any prescription.
The most important thing here is to educate the patient. As long as the patient understands what is happening and the possibility that this may be transient, I may write a prescription earlier.
Disposable lenses can help
Dr. Amos: Refractive shifts can actually occur quite suddenly, within a matter of hours or days, certainly weeks, so they tend to be relatively sudden as opposed to occurring over many months or years. How long one waits before prescribing new lenses depends on the drug used for controlling the diabetes. For instance, good compliance with insulin usually brings the blood glucose level within a normal range in a compliant patient in about 6 to 10 weeks. Poor compliance, obviously, will be longer.
It has also been reported in the literature that oral hypoglycemics may take many months, even as long as 1 year (and I have seen it go longer than that), to bring the person under appropriate control. I prefer to prescribe when the refractive error remains the same on two occasions, separated by 1 to 2 weeks.
It's important to note that the refractive shift almost always returns to its initial baseline. It's also important to remember that disposable contact lenses can be of great assistance in refractive error management during these periods of refractive error fluctuation due to the blood glucose.
PCON: How do you manage a diabetic patient who has sixth nerve palsy? And what other conditions should ODs be aware of in making the differential diagnosis?
Dr. Cavallerano: The length and course of the sixth nerve make it much more vulnerable to injury than other cranial nerves, but that also means it can be affected by a lot of different things that may be nondiabetic in origin and potentially life-threatening.
So, with sixth nerve palsy and any nerve palsy, you want to exclude other causes. With sixth nerve palsy, especially, you could have intracerebral abnormalities such as pseudotumor cerebri, a subdural hematoma or an aneurysm to the vessels leading to the sixth nerve, intracranial tumors or metastatic tumors from the breast.
You can have carotid artery aneurysms; and, it has even been noted that different viruses - chickenpox, malaria, measles, meningitis - can cause sixth nerve palsy. Myasthenia gravis can cause sixth nerve palsy. There are many things that can cause sixth nerve palsy, and when I see a sixth nerve palsy, I want to do a total evaluation and have neurological consultation.
The patient's diabetologist or intern should be notified, and the case should be discussed. The patient needs to be monitored because if the palsy is getting worse, the patient may need to be referred for brain scanning or neurological consultation.
Patching, prisms for palsy
As far as dealing with the symptoms of the double vision, patient education is paramount. Getting rid of the double vision depends on the patient's needs, habits, work and inclination, so it is possible to patch a patient. Sometimes the patch may be an actual eye patch or pad; sometimes it will just be a matter of frosting a person's glass. Very rarely have I found Fresnel prisms useful in these circumstances.
There are circumstances where patching is problematic. Let's say a patient has a right sixth nerve palsy and is amblyopic in the left eye. If you are going to patch the eye with the palsy, you force him or her to use the weak eye and that becomes a problem. So you're not always patching the eye that has the palsy.
The bottom line is that all of these cases have to be managed on an individual basis by determining what works best for the patient.
Dr. Amos: With regard to managing an acute sixth nerve palsy, it depends on the magnitude of the deviation. Almost all of these cases require neurologic evaluation because the sudden onset of a strabismus in an adult is not normal, and you can't necessarily assume that it's diabetic in nature even in a diabetic patient. But having ruled out other etiologies, such as a tumor or cerebral vascular accident, once you decide on the optical management, the type of management depends on the magnitude of deviation. For deviations under 15 - or perhaps at the most 20 prism diopters - prism may be most appropriate. For larger deviations, it may be necessary to patch or occlude the deviating eye until the condition has resolved or some other form of management has been instituted.
I feel a patch works best for angle deviations and because these are incomitant deviations, you get variability in the angle depending on the direction. For small angle deviations, Fresnel prism should be attempted first, but it isn't always tolerated by patients because of the slightly blurred vision they can experience with this press-on type prism. Of course, ophthalmic or regular ground-in prism also remains an option.
You do not want to focus on the optical management, however, without giving some consideration to the underlying etiology. It is usually wise to coordinate a neurologic consultation with the patient's primary care physician in the event of any acquired ophthalmoplegia.
PCON: How often should a diabetic patient undergo a dilated fundus examination? And should ODs order fluorescein angiographies?
Dr. Cavallerano: A patient with diabetes should have a dilated fundus examination at least once a year. I recommend that to all of my patients, and I also recommend that they pick a time of the year that is easy to remember.
For a patient who has no or minimal retinopathy, we recommend annual eye examinations. For patients with type 1 diabetes, we recommend that they have their initial exam for diabetic eye disease within 5 years of diagnosis or at puberty, whichever comes first. For a person with type 2 diabetes, we recommend a dilated exam upon diagnosis and at least annually thereafter.
In regard to pregnancy, we recommend that women have their eyes examined before planned pregnancies, if possible, and then early in the first trimester. We usually see our patients two or three times during the pregnancy, usually once a trimester, then usually 3 months postpartum.
If patients have different levels of retinopathy, the schedule is altered. If a person has mild nonproliferative diabetic retinopathy, the risk of developing proliferative disease in 12 months is 5%, so it is safe to let that person go for a year between exams. If a person has moderate nonproliferative diabetic retinopathy, the risk of proliferative retinopathy developing within in a 12-month period ranges from 12% to 27%. In those circumstances, we certainly don't want a person to go 12 months; we'll recommend about a 6-month follow-up.
For very severe nonproliferative retinopathy, the risk of progressing to proliferative disease within a 12-month period exceeds 50%, so we want to see those patients at 3 to 6 months. On top of that, we have diabetic macular edema considerations, and macular edema can be present at any level of retinopathy. For those patients with macular edema, we follow them every 3 months.
I feel very strongly that optometrists should not be ordering fluorescein angiograms for the diabetic patient. There are two main reasons for doing fluorescein angiography for diabetes. One is for determining the treatment strategy for clinically significant macular edema, and the optometrist will not be doing that, the vitreoretinal specialist will be doing it.
The second reason is for research programs. We do fluorescein as part of research programs. To use a fluorescein to determine the level of proliferative disease or nonproliferative disease is a misuse of the test, and it probably is one of the most overused, inappropriately used tests for patients with diabetes.
It is not uncommon for a patient to come in and say, "Well, I had a baseline fluorescein angiogram," and as far as the diabetes is concerned there shouldn't be any "baseline fluorescein angiography." The diagnosis of level of retinopathy and macular edema should be made from clinical observation without the fluorescein. While there is relatively low risk associated with fluorescein, there are potential complications, and there have been documented deaths following fluorescein.
Dr. Duenas: I recommend dilated exams at least yearly, but if I see a change that I'm concerned about, I will recommend them more often. The guidelines developed by the AOA are very good in terms of frequency of examination based on exam criteria. As we get more involved in managed care, things like HEDIS [Health Plan Employer Data and Information Set] standards and NCQA [National Committee for Quality Assurance] become an issue.
Basically, fewer than half the patients in the country who are diagnosed with diabetes are receiving annual dilated eye exams, which is inexcusable. And you would think annual dilated exam rates would be better in a health maintenance organization or managed care system, but they are not. I think in the future we are going to see some stratification of risk and thus an additional stratification of time frames for dilated eye exams.
Regarding fluorescein angiography, the only need for this procedure is in the treatment of macular edema. The fluorescein angiograph is required in this instance to help better identify where laser spots should be placed. For proliferative retinopathy, you don't need to do fluorescein angiography, because if the patient needs a panretinal photocoagulation that's going to be done the same way, regardless. So, I think there's a little overemphasis on the need for fluorescein.
Consult AOA guidelines
Dr. Amos: A dilated fundus exam is needed at least every year, and that gets back to the stage of diabetes. Here is where one can refer to the AOA clinical practice guideline for management of the patient with diabetes.
Once you stage the disease, these guidelines give the clinician some guidance about whether fundus photography is advisable or whether fluorescein angiography is recommended.
Every diabetic needs to have an annual fundus examination, and this is where optometry can play a role in the annual examinations of all diabetics. The big message is that there are still many diabetics who don't know to get a dilated fundus examination every year.
Optometrists can order fluorescein angiography, but it depends on the setting they're in. I know optometrists who have access to this procedure and who, in some cases, actually perform the procedure, while others prefer to make the appropriate retinal referral. I don't have any problem with optometrists who are properly trained performing the procedure in a given setting.
PCON: When does diabetic retinopathy warrant a vitreoretinal consult?
Dr. Cavallerano: Any patient who might be a candidate for laser surgery should have a consult or a referral. That depends, of course, on how the individual optometrist works with his or her retinal specialist. For any patient who is a potential candidate for laser surgery, which includes patients with very severe nonproliferative retinopathy, early proliferative disease and macular edema or clinically significant macular edema, a consultation would be in order.
Dr. Duenas: It is important to work closely with a vitreoretinal specialist, but I don't refer my patients unless I feel that laser photocoagulation will be necessary. My view is that if we're doing our job - getting these people earlier into treatment and monitoring the complications in our management - we can severely limit the need for laser photocoagulation.
When we do laser photocoagulation, it's sort of an indictment that the system has somehow failed the patient. For most patients who require photocoagulation, if you look back through their course of treatment, you will often discover gaps in treatment, delayed detection, uncontrolled hypertension, uncontrolled blood sugars or other factors which have contributed significantly to their visual morbidity.
Dr. Amos: The issue of a vitreoretinal consult should take the clinician back to the AOA guidelines. The optometrist needs to stage the disease. In cases of mild or perhaps moderate nonproliferative diabetic retinopathy, if the macula's clear and the patient is compliant, no referral may be needed. I usually use severe nonproliferative diabetic retinopathy as a guideline, and I refer for a vitreoretinal consult at this point. At the first sight of macular edema, I'll refer for a retinal consult.
In mild or moderate cases, a great deal depends on whether there's macular edema present, and of course any proliferative diabetic retinopathy must have a retinal consult. I can't answer this question in simple terms because it depends on whether there's macular edema or not, but perhaps at the moderate level and certainly at the severe level, I would recommend getting a retinal consult.
PCON: Should optometrists perform glucose screenings in the office for diabetic patients?
Dr. Amos: In theory, it makes some sense, but you need to have the proper equipment to do this, and you have to accept a degree of responsibility because you're functioning as a lab. One of the other things optometrists can do is to ask the patient about his or her A1C values. The A1C values are the results of the glycosolated hemoglobin test. This test informs the doctor and the patient, retrospectively, what the control has been for the past 60 days.
This test lets you know what the patient's long-term care has been. One of the important roles for the optometrist is to reinforce to patients about how important it is to stay under good control because diabetic retinopathy is the leading cause of blindness; it is a serious disease.
Dr. Cavallerano: Doing a glucose test in the office for a patient with diagnosed diabetes is relatively useless. The only time I consider it, or do it here, is if I have a patient who comes in and looks like he or she is going into reaction - then I may want to get a blood sugar level in order to see whether his or her blood sugar is down to 40.
As far as routinely doing blood glucose screening in the office, I don't see any real value in it. Once again, the education issue is more important; patients need to know it's important to self-monitor their blood sugar level. To get a blood sugar level of 130, 120 or 180 at 10 a.m. won't do anything to help manage that patient properly.
Teaching a patient about glycosolated hemoglobin and encouraging him or her to ask his or her doctor about A1C levels is much more valuable. If a patient comes in and tells me that his or her A1C is 6.1, that's fine. I feel better about that than a patient who comes in and tells me, "My blood sugar was 110 this morning." Maybe he or she knew he or she was coming in today and made sure the blood sugar was 110.
For patients who do not have diabetes and you suspect it, once again I think that getting a random blood sugar sample will be relatively useless. If I suspect a patient has diabetes, I'll refer that person to his or her physician or internist for medical evaluation.
Consider OSHA rules
There is another issue in regard to random blood sugar testing that a lot of people seem to ignore as well, and that's OSHA [Occupational Safety and Health Administration] requirements concerning hazardous waste. If I take blood in my office, I have generated hazardous waste that must be disposed of properly, and if I use a lancet to prick a person's finger, once again I have generated hazardous waste that needs to be disposed of properly.
It's an important issue to raise, and there are times when we do take random blood sugar, but it's more to make sure I don't have a patient lying on my floor unconscious than it is to do anything about managing diabetes.
PCON: What other issues do you stress in patient education?
Dr. Cavallerano: It's important for patients with diabetes to be fully aware of their disease and to be educated about the importance of eye exams. A frequent question is: "What can I do to keep from going blind? I've heard that diabetes can really hurt my eyes. What can I do?"
What I normally tell them is that there is absolutely nothing they can do that guarantees they won't have eye disease from diabetes. But we know from the Diabetes Control and Complications Trial that good control of blood sugar levels reduces the risk of onset and progression of retinopathy in patients with type 1 diabetes mellitus.
I tell them that maintaining regularly scheduled eye examinations as indicated, which is at least once a year, and controlling hypertension, cholesterol, lipids and any anemia, if present, are also important systemic complications that can impact the progression of eye disease.
It's important for patients who require laser treatment to know that laser treatment doesn't cure eye disease; it reduces the risk of vision loss. So you can have laser treatment for macular edema, and you have reduced your risk of moderate vision loss from 25% to 30% down to around 12% to 15%.
When educating patients, optometrists should be familiar with the diabetic disease process and with the findings of major clinical trials that have determined the management course for diabetic retinopathy. The four main trials are: the Diabetes Control and Complication Trial, the Diabetic Retinopathy Study, the Early Treatment Diabetic Retinopathy Study and the Diabetic Retinopathy Vitrectomy Study.
Dr. Duenas: The ADA is coming out with a recommendation that all adults older than 45 should be screened for blood sugar. It's one of the easiest tests we can perform in an office. The reasons for considering testing patients are: obesity (>120% of desirable body weight); having a first-degree relative with diabetes; if they're members of a high risk ethnic population such as African Americans, Hispanics, Native Americans or Asians diagnosed with diabetes mellitus; have delivered a baby weighing more than 9 lb.; are hypertensive; have an HDL cholesterol level of 35 mg/dL or a triglyceride level of >250 mg/dL.
These are things that should be going through the clinician's mind when he or she has the patient in the chair. If we're seeing these patients annually for their eye exams and they have diabetes for 7 to 10 years before it's diagnosed, then we're missing opportunities to diagnose the disease early and prevent complications.
Criteria for glucose tests
The earlier we find these patients, the better. And that's where optometry fits in, because not only are we managing those patients, we're diagnosing those patients earlier. In my office, we do routine blood sugars on patients we suspect might have diabetes based on ocular signs and symptoms as well as risk factors published by the ADA.
We have a certificate of exemption from the Health Care Financing Administration to perform blood sugars in the office, and this allows us to be reimbursed for doing them. It's something I would encourage all optometrists to do. The certificate costs only $100 per year.
Not only does my early detection reduce complications of the disease process, but it also serves to better unite us with the treatment team. I have made the most significant inroads with treating physicians by referring previously nondiagnosed patients with diabetes mellitus for treatment.
As primary care practitioners, we should identify patients with risk factors and screen patients for diabetes mellitus while they are in our office. Any random capillary blood sugar over 200 mg/dL most likely means the patient has diabetes and a confirmation fasting blood sugar should be ordered. In-office testing machines are extremely accurate and easy to use.
In addition, proper sterile techniques should include the use of alcohol preps, gloves, sterile single-use auto lancets and transfer pipettes. Waste disposal is also no problem. I use an Isolyser SMS (sharps management system, Isolyser, Norcross, Ga.), which contains a liquid storage canister for collection and sanitation. When full, a catalyst pack is added, which transfers the system into solid mass. This can be disposed of in regular trash and meets OSHA guidelines.
Patients appreciate the service and those we diagnose are our most loyal patients. Also, their treating physician always sends them back for their dilated eye examinations, a winning combination for the patient and a tremendous cost savings to society.
Dr. Amos: Optometrists have a real role - although they have been underutilized - in managing diabetic retinopathy and monitoring patients on an annual basis for the development of diabetic retinopathy. We could be of greater assistance to the primary care physician, and I encourage optometrists to reach out and develop these liaisons. We need to be more proactive in this area than we have been.
For Your Information:
- Neither Dr. Amos, Dr. Cavallerano nor Dr. Duenas has a direct financial interest in any products mentioned in this article, nor are they paid consultants for any company mentioned.
- The Clinical Practice Guideline, "Care of the Patient with Diabetes Mellitus," is available from the American Optometric Association, 243 N. Lindbergh Blvd., St. Louis, MO 63141; (314) 991-4100; fax: (314) 991-4101; http: //www.aoanet.org.