In this presentation, Dr. Brookes discusses about the importance of history taking in a glaucoma clinic.
Lecturer: Dr. John Brookes, Moorfields Eye Hospital, London
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DR BROOKES: So I’m just gonna talk a little bit about taking a glaucoma history, but particularly looking at risk factors and epidemiology of glaucoma. And the reason I thought this was important is I was reading an old textbook, and I read this sentence, that most ophthalmologists on Planet Earth are confused regarding the diagnosis and management of glaucoma. Which I thought was quite amusing. And also it went on to say that history taking is the most neglected part of glaucoma management. But we can see why that might be the case. Because most cases of glaucoma are asymptomatic. A pressure over 21 is not synonymous with glaucoma. There’s an inability to appreciate the pitfalls in pressure measurement. And there’s an inability to appreciate other diseases that might mimic glaucoma. Well, where do we find our patients from? Well, as you know, most glaucoma patients are referred from optometrists, from the GP, or from screening because of a family history of glaucoma. And many of these patients are asymptomatic. It can be symptomatic, from vision loss. It can be symptomatic from episodes of intermittent angle closure, and patients can present with pain, with very high intraocular pressures. But what’s more important, really, in the history, is looking for risk factors. To decide what is the likelihood of a patient sitting in front of you — what risk factors they have for developing glaucoma. So these are some of the risk factors. So there’s strong evidence, very strong evidence, that older age increases the risk of glaucoma, as does ethnic origin, elevated intraocular pressures, and change in the optic nerve. There’s moderate evidence that a family history of glaucoma increases the risk. But fairly modest evidence that a history of diabetes or hypertension is a risk factor for glaucoma. I’m just gonna look at some of the evidence in large epidemiological studies about some of these risk factors. And what are the risk factors in certain groups of them developing glaucoma. These are large, quite old, now, epidemiological studies, looking at the influence of age and race as a risk factor for glaucoma. So you can see in one study… In the group of patients… In the group of — in this group of people — aged between 40 and 49 years old — the prevalence of glaucoma is just over 1%. But if you look in this group of patients over the age of 80, and these are African-American patients, the prevalence of glaucoma is over 10%. And there are other epidemiological studies showing that age is an important factor. In this group, in patients — sorry, in the group of people under the age of 75, the prevalence is 3.4%. But in people over the age of 75, again, it approaches 10%. And you can see in the Black population, the difference is even more startling in the group over 75. The prevalence was over 20%. We always ask about family history when asking about patients with glaucoma. But we don’t — and we do know that family history increases the risk of glaucoma. We also know that the inheritance of glaucoma is not… Sorry. The inheritance of glaucoma is multifactorial. And it’s a polygenic disease. And you can see again from some of these epidemiological studies the lifetime risk of glaucoma in somebody 80 years of age is 10 times higher if there is a positive family history. This is from an old epidemiological study as well, looking at family history. And this shows the odds ratio of a family member having glaucoma. So, for instance, if there’s primary open-angle glaucoma in a parent, the odds ratio is about 1.3. That’s 1.3 times higher than if you didn’t have a parent with glaucoma. If there’s — if you have primary open-angle glaucoma in a sibling, then the risk of glaucoma is three times greater. And the odds ratio if you have a first-degree relative is almost two. Two times. Diabetes is thought by many patients to be a risk factor for glaucoma. But the evidence is quite modest. So you can see in one epidemiological study the risk of glaucoma is about twice that in diabetics than it was in non-diabetics. But interestingly, there was a large study — you’ll be aware — of the Ocular Hypertension Treatment Study, which showed that diabetes was protective. This actually was probably because of case selection, and the patients with diabetes — many were excluded from the study. Hypertension is a moderate risk factor for glaucoma. And again, if we look at some of the epidemiological studies, in the Blue Mountains Eye Study, glaucoma was much more common in patients with systemic hypertension than in patients without elevated blood pressure. And then another couple of studies showing that individuals with a systolic blood pressure over 130 millimeters of mercury had a higher prevalence of primary open-angle glaucoma. As part of our other parts of our history taking, we look at these other factors, which you’re very familiar with. And we’ll look at some of these in relation to patients with glaucoma. So let’s look at refractive error. So we do know that myopia has an increased frequency amongst patients with both ocular hypertension and primary open-angle glaucoma. In one study, about 60% of patients progressing from ocular hypertension to primary open-angle glaucoma were myopic. And this is an epidemiological study from China, showing that subjects with more than 6 diopters of myopia had a significantly higher frequency of developing glaucoma than lower degrees of myopia or patients who are emmetropic. Also it’s important to look in the past ocular history at other factors. For instance, if the patients had previous surgery. Patients having vitreoretinal surgery, for instance, are more at risk of developing glaucoma. And it’s important to look at other factors. Is it the patient’s only eye? Have they had previous laser refractive surgery? Are they pseudophakic or phakic or aphakic? And it’s also important in children to look at amblyopia and anisometropia, because these are often associated with asymmetric optic disc appearance. There are several factors in the past medical history that we need to take account of. So, for instance, patients with asthma. So this might preclude us having to use beta blockers, for instance, which might exacerbate the chest problem. If there’s a past history of rheumatoid arthritis, it might make patients have difficulty in instilling the eye drops. Heart block might stop us using certain types of drops like beta blockers, a history of migraine or Raynaud’s might increase the risk of normal-tension glaucoma. And there’s many papers on asthma, looking at the respiratory side effects of topical beta blockers, dating back really to the 1970s and ’80s, when beta blockers were first used. It’s also important to know which drugs — other drugs the patients are taking. Because some of these drugs might interact or interfere with our glaucoma treatment. So, for example, patients on anticoagulant drops — that might interfere with our glaucoma surgery. Patients on systemic beta blockers — that might influence the choice of our topical treatment. Because there may be no point in using a topical beta blocker, if the patient is already taking a systemic beta blocker. And it’s also important to know if there’s a past history or continued use of steroids. Because that might affect or have caused the elevated intraocular pressure. And also there may be interactions with our classes of drugs that we use for glaucoma. So let’s just look at some of the interactions. So for beta blockers, drugs that elicit bradycardia or cardiac arrhythmia can interfere with the effectiveness of the topical beta blocker. And these are three examples. So an example of a cardiac glycoside is digoxin. An example of a sodium channel blocker, quinidine, procainamide, lidocaine, an example of calcium channel blockers, verapamil and diltiazem. So these can interact with our topical beta blockers. And also remember that beta blockers can mask the hypoglycemia in diabetics. Carbonic anhydrase inhibitors, so dorzolamide and brinzolamide — there can be interactions with numerous drugs. So it’s important to take a full drug history. Be aware that prostaglandins — we try and avoid them in early pregnancy. And I think the most important interaction to remember is alpha-2 agonists, such as brimonidine. So brimonidine can cross the blood-brain barrier, and in very small children can have severe systemic side effects. So when you’re treating children with glaucoma, always avoid brimonidine in children under the age of about 6 years. Apraclonidine, or iopidine, is an alpha-2 agonist as well, but it doesn’t cross the blood-brain barrier, so it’s much safer to use in children than brimonidine. So apraclonidine. The other name is iopidine. The same drug. It’s safer to use in children. This was meant for our residents, but it’s very important, because when we’re doing medical records, it’s important that our records are dated, we have diagnoses and drops written, it’s signed, and appropriate follow-up is taken afterwards. But ignore that. It was meant for my residents. So thank you. That’s a quick history taking.
June 6, 2017