Glaucoma overview © Michelle Baker This overview provides general information related to Glaucoma and does not take into account your personal circumstances
GLAUCOMA INFORMATION SHEET
Glaucoma Information Sheet
TABLE OF CONTENTS Glaucoma Overview 3 Are You At Risk Of Glaucoma? 3 Eye Anatomy 4 What Are The Glaucoma Types? 4 Glaucoma Symptoms 5 Who Should Be Checked For Glaucoma? 6 How Is Glaucoma Diagnosed? 6 How Does Glaucoma Evolve? 7 What Is The Treatment For Glaucoma? 8 Glaucoma Eye Drops 8 Glaucoma Laser Surgery 9 Glaucoma Surgery 10 Micro Invasive Glaucoma Surgery (MIGS) 10 Trabeculectomy 10 Glaucoma Drainage (Tube) Device 11 Recently Diagnosed With Glaucoma 11 Life Style Changes To Help Control Glaucoma 12 Is Glaucoma Associated With Cataract? 13 Can I Still Drive With Glaucoma? 13 Pregnancy and Breast Feeding With Glaucoma 13 What Can Be Done For Low Vision Or Blind Patients? 14 How Can I Find More Information On Glaucoma? 14
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Glaucoma Information Sheet
GLAUCOMA OVERVIEW How can I find more information on Glaucoma? 1. From your 2. 3. 4. 5.
ophthalmologist (eye specialist) - Ask me!
Glaucoma Australia RANZCO Glaucoma Foundation World Glaucoma Association
Glaucoma is the name given to a group of eye disease processes which damage the optic nerve and can lead to irreversible vision loss and blindness. Glaucoma is the second most common cause of blindness worldwide, and at least 1 in 200 Australians have glaucoma at age 40, and this rises to 1 in 8 Australians over age 80. Glaucoma is often caused by an elevated pressure inside the eyeball, called intraocular pressure. The level of intraocular pressure which causes damage to the optic nerve varies between people. If glaucoma is detected early, treatment to reduce the intraocular pressure can prevent or reduce vision loss in most patients.
ARE YOU AT RISK OF GLAUCOMA?
Although anyone may develop glaucoma, some people have a higher risk: • • • • • • • • • • • •
older age high eye pressure family history of glaucoma African or Asian descent diabetes refractive error (short sighted or long sighted) experience migraines high or low blood pressure cortisone (steroid) medication previous eye surgery or eye injury history of poor blood circulation obstructive sleep aponea
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Glaucoma Information Sheet
EYE ANATOMY DRAINAGE SYSTEM OF THE EYE
A major risk factor for developing glaucoma is raised intraocular pressure, which occurs when fluid in the eye, used to transport important nutrients to the lens and cornea, and helps hold the eyes shape, accumulates and cannot drain naturally. The fluid in the eye, known as aqueous humour, is produced by the ciliary body (located in the posterior chamber of the eye, behind the coloured part of the eye called the iris). The aqueous humour then flows through the pupil to the anterior chamber of the eye where it drains out of the eye through a sieve-like structure called the trabecular meshwork, into Schlemm’s Canal and out through the Aqueous veins. Many (but not all) types of glaucoma occur when the rate of aqueous humour pumped into the eye by the ciliary body is greater than the rate of aqueous humour flowing out the eye, through the trabecular meshwork.
WHAT ARE THE GLAUCOMA TYPES? There are many types of glaucoma. Glaucoma can be divided into two categories based on the status of drainage angle of the eye (‘open’ vs. ‘closed’). Open angle glaucoma develops slowly and the aqueous humour cannot drain properly due to some resistance to flow in the trabecular meshwork. When no cause is found for open angle glaucoma with high intraocular pressure (>21 mmHg), it is termed Primary Open Angle Glaucoma, or if the intraocular pressures is within the normal range (< 21 mmHg) it is termed Normal Tension Glaucoma. Normal Tension Glaucoma may be caused by poor regulation of blood flow to the optic nerve. Raised intraocular pressure without any damage to the optic nerve is termed ‘Ocular Hypertension’.
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Glaucoma Information Sheet
Angle closure disease is often asymptomatic but sometimes can progress rapidly within 24 hours due to the flow of aqueous humour being blocked called Acute Primary Angle Closure. Besides glaucoma being classified as a primary disease it can also be classified as occuring secondary to other disease processes such as inflammation, pigment dispersion, pseudo-exfoliation, iridocorneal erosion syndrome, trauma, steroid-induced and diseases affecting the retina. Most glaucoma occurs in older adults, but childhood glaucoma can occur including congenital glaucoma (from birth and often hereditary) and earlyonset forms can occur referred to as juvenile glaucoma. ‘Glaucoma Suspect’ is a term used when a person might be showing early signs of glaucoma, and requires ongoing monitoring.
GLAUCOMA SYMPTOMS Most people affected with glaucoma are unaware that they have glaucoma because there are no symptoms in the early stages of glaucoma (silent thief of sight). Glaucoma tends to be asymptomatic until a very late stage in the disease process. As your peripheral vision is not as sensitive as your central vision, it’s difficult to notice any early changes to your vision but your vision is being damaged. In addition, as one eye tends to be affected more than the other, the better eye may compensate. Very occasionally, glaucoma can develop suddenly as an opthalmology emergency in primary acute angle-closure and can cause: blurred vision, eye pain, nausea and vomiting, red eye, headache, and seeing haloes around lights.
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Glaucoma Information Sheet
WHO SHOULD BE CHECKED FOR GLAUCOMA? In general, all individuals between 35-40 years should undergo an eye examination for glaucoma, which should include examination of the drainage angle (gonioscopy), intraocular measurement and examination of the optic nerve head. In general, after the age of 40 years, a glaucoma examination should be done every 2-3 years, and a check-up every 1-2 years is advised after the age of 60 years. The appropriate time intervals between glaucoma examinations may vary, depending on your risk factors. All individuals with a positive family history of glaucoma should undergo a glaucoma examination, and maintain follow-up at regular intervals. First degree relatives of glaucoma patients have up to 50 times the risk to develop glaucoma, compared to the normal population. Patients with diabetes also need monitoring for glaucoma.
HOW IS GLAUCOMA DIAGNOSED?
Glaucoma diagnosis involves undergoing a comprehensive eye exam. As the peripheral vision is usually affected earlier than the central vision in glaucoma, only specialised clinical examination of the eye and diagnostic methods can pick up early cases. Clinical examination to assess glaucoma involves six tests: 1. Measurement of intraocular pressure, the pressure inside the eyeball. 2. Central corneal thickness is important as it is an independent risk factor for glaucoma and the thickness of the cornea affects the intraocular pressure reading. 3. Gonioscopy (examination of the drainage angle of the eye) allows for differentiation between an open angle and a closed angle glaucoma which is important because the treatment approach differs. 4. Optic nerve assessment and photos. Formal assessment of the optic nerve and optic nerve “disc” photographs are taken as a baseline for future comparison.
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Glaucoma Information Sheet
5. OCT scan is a computerised assessment of the optic nerve to assess for structural damage of the optic nerve, compared to age-matched controls. 6. Visual field testing measures functional vision loss. All of these parameters are considered collectively before a diagnosis of glaucoma can be made or excluded. Sometimes it is not possible to determine whether one has glaucoma and these patients are called a ‘Glaucoma Suspect’ and require ongoing monitoring.
HOW DOES GLAUCOMA EVOLVE? Glaucomatous damage to the optic nerve is irreversible vision loss, so what is lost cannot be recovered. It is important to regularly monitor patients with glaucoma to ensure that the intraocular pressure is sufficiently low to offset further optic nerve damage and prevent increasing peripheral vision loss. In late disease, central vision loss may ensue (blindness) but this is less common with today’s treatments.
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Glaucoma Information Sheet
WHAT IS THE TREATMENT FOR GLAUCOMA? Glaucoma treatment aims to control the intraocular pressure and halt glaucoma progression. Glaucoma treatment will not improve vision loss. The only modifiable factor to prevent glaucoma treatment is lowering of intraocular pressure, which can be achieved in many ways. All these approaches have different side-effects and safety profiles. Most glaucoma can be managed with the use of glaucoma eye drops, laser or incisional surgery, or a combination of all three. Various modalities of treatment are available: 1. Glaucoma eye drops 2. Systemic treatment (oral tablets) 3. Glaucoma laser 4. Glaucoma surgery I will discuss the best treatment option(s) with you for your type of glaucoma.
GLAUCOMA EYE DROPS
Glaucoma eye drops (and tablets) work by lowering the intraocular pressure by either decreasing fluid production in the eye or increasing fluid drainage from the eye. There are many different types of glaucoma eye drops which can be given alone or in combination. Eye drops need to be instilled correctly and are limited by side effects and drop adherence.
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Glaucoma Information Sheet
GLAUCOMA LASER
Glaucoma laser has a key role in glaucoma treatment. Selective Laster Trabeculoplasty (SLT) allows low dose pulses of light energy directed at the drainage angle to stimulate the trabecular meshwork and enhance drainage of aqueous humour out of the eye, which then lowers the intraocular pressure. SLT is an effective non-invasive, painless procedure with an excellent safety profile which typically works for 24 months, and can be repeated. Laser peripheral iridotomy (LPI) involves making a small hole in the iris and is used to widen the drainage angle for patients with narrow drainage angles or angle closure glaucoma. If LPI does not work (around 25% do not succeed) a different type of laser (laser iridoplasty) or cataract surgery (lens extraction) may be required to widen the drainage angle effectively. LPI is a safe procedure and generally most complications are mild and do not result in permanent damage. Transcleral Diode Laser cyclophotocoagulation reduces the amount of aqueous humour produced by the ciliary body in the eye and is typically performed when glaucoma doesn’t respond to other treatments e.g. MicroPulse diode, Cyclodiode.
GLAUCOMA SURGERY
The failure of glaucoma eye drops and glaucoma laser to control the intraocular pressure and consequently glaucoma progression, is an indication for glaucoma surgery. Glaucoma surgery may also be performed when there is an allergy to the glaucoma eye drops, poor glaucoma eyedrop adherence issues or if the glaucoma continues to progress, despite conservative treatment. Advanced glaucoma, and other specific glaucoma types, are also an indication for glaucoma surgery and the best possible surgery option(s) for your glaucoma type will be discussed with you. The goal of glaucoma surgery is to lower the intraocular pressure to prevent further glaucoma progression.
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Glaucoma Information Sheet
MICRO - INVASIVE GLAUCOMA SURGERY (MIGS) Several new procedures have been developed which are quicker and safer than the trabeculectomy surgery known as micro-invasive glaucoma surgery (MIGS) but with limited long-term data.
iSTENT
iStent inject G2W™ is typically reserved for mild-moderate glaucoma cases. It can be performed as a solo-procedure or with cataract surgery. iStent inject G2W™ comprises of two 0.4mm titanium stents which are the smallest medical appliance in the world. They are implanted through the trabecular meshwork (drainage angle) and enhance fluid outflow into Schlemm’s Canal, the main drainage channel out of the eye. iStent inject G2W™ can reduce reliance on intraocular pressure-lowering medications. Seven-year study results have been published.
HYDRUS
The Hydrus™ microstent is 8mm long (approximately the size of an eyelash) and opens Schlemm’s canal. It is made from nitinol, a flexible nickel-titanium alloy. Five-year study results have been published.
XEN
The XEN™ implant is a 6mm gelatin stent with a 45 micron lumen which can be performed as a solo-procedure or with cataract surgery for moderate glaucoma. XEN™ lowers intraocular pressure by draining fluid from inside the eye, through the stent to the space under the conjunctiva with mitomycin-C, similar in principle to a trabeculectomy.
PRESERFLO
PreserFlo™ is a novel device made from “SIBS”, the same material used in cardiac stents and it measures 8.5 mm in
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Glaucoma Information Sheet
length with a 70 micron lumen. PreserFlo lowers intraocular pressure by draining aqueous humour from inside the eye through a stent to the space under the conjunctiva, with mitomycin, and is a hybrid of trabeculectomy and glaucoma drainage (tube) device surgery.
TRABECULECTOMY
A trabeculectomy is the most traditional surgical method to treat moderate to advanced glaucoma and remains the gold standard. It works by lowering the intraocular pressure through the making of a channel in the eye wall which allows fluid to escape from the eye in a controlled manner. Anti-scarring medication (mitomycin-C) is used to stop the flap from healing over, and special stitches control the amount of aqueous humour draining from the eye. Trabeculectomy surgery may lead to several and some serious, complications, including infection, mild ptosis (droopy eyelids) and loss of vision.
GLAUCOMA DRAINAGE (TUBE) DEVICE
A glaucoma drainage implant (e.g. Baerveldt tube, Paul tube) is used in certian types of glaucoma and also when traditional surgery has failed. Tube surgery may lead to serious complications, including infection. Tube surgery may lead to several and some serious, complications, including infection, mild ptosis (droopy eyelids) and loss of vision.
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Glaucoma Information Sheet
RECENTLY DIAGNOSED WITH GLAUCOMA If you have recently been diagnosed with glaucoma you might be feeling overwhelmed and concerned for your vision. While there is no cure for glaucoma it usually can be managed with laser and/or drops . Please know you will be supported and are not alone. The first steps to follow are easy to access at Glaucoma Australia.
ARE THERE ANY CHANGES IN LIFE STYLE TO HELP CONTROL GLAUCOMA? There are lifestyle changes which can help your eye health including smoking cessation, regular exercise, and a healthy diet. However, note that not every type of exercise is good. In those with certain types of glaucoma called pigment dispersion glaucoma vigorous exercise is discouraged. In addition, exercises e.g. yoga with head-down or inverted positions which raise the intraocular pressure may damage the optic nerve and may need to be avoided but there is no evidence to confirm this currently. Care also needs to be taken with swimming goggles as smaller sized goggles can significantly increase the intraocular pressure. Vitamin D deficiency is likely an independent risk factor for glaucoma and your vitamin D level will be checked at diagnosis and over time. Ultimately, regular monitoring is perhaps the single most important thing you can do for your eyes, to pick up early signs, or progression, of glaucoma, and then lowering intraocular pressure to prevent further damage and vision loss.
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Glaucoma Information Sheet
IS GLAUCOMA ASSOCIATED WITH CATARACT Cataract is an opacity in the lens or its capsule that normally occurs with ageing, and it may eventually lead to vision impairment. Glaucoma and cataract can both co-exist in the same eye. Visually impairing cataracts are treated by surgery, which will remove the opaque lens and replace it with an artificial lens. If there are no other abnormalities or complications, then vision is fully recovered after surgery. Patients with glaucoma should undergo a comprehensive individualised assessment to determine the best surgical strategy. Advanced glaucoma or intraocular pressure poorly controlled by medical/laser treatment should be evaluated for combined glaucoma/ cataract surgery.
CAN I STILL DRIVE WITH GLAUCOMA? Glaucoma patients with visual field defects are at an increased risk for motor vehicle accidents. Although central vision is usually spared until late phases of the disease, glaucoma may affect the peripheral vision at early to moderate phases and a visual field needs to be done to assess if you meet the driving standard. A specific type of visual field called an Estermann is performed to assess your eligibility for driving; if the criteria is not met, a restricted licence may still be possible.
HOW DOES PREGNANCY AND BREAST FEEDING AFFECT GLAUCOMA? Any glaucoma eye drop used by the Mother can get absorbed into the circulation and it may affect the foetus;
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Glaucoma Information Sheet
also some medicines are secreted in breast milk for breast feeding Mothers. There is a risk to the foetus with all glaucoma medications – especially in the first trimester of pregnancy. If you have glaucoma and are planning to start a family, please discuss this with me. Risk to the foetus with all glaucoma medications.
WHAT CAN BE DONE FOR LOW VISION OR BLIND PATIENTS? Losing your vision can cause feelings of anxiety, fear and even anger. Understandably a diagnosis of a serious eye disease can create worry about a loss of independence and uncertainty about the future. After a proper assessment by a specially qualified eye-care professional in providing low vision services, you can be supported on how to maximise vision through illumination and low vision aids. Talking to others who have experienced vision loss may help by sharing strategies, feeling and information. Please visit the Vision Australia website including the Telelink program and the Talking Book library. You are not alone.
HOW CAN I FIND MORE INFORMATION ON GLAUCOMA? 1. 2. 3. 4. 5.
From your ophthalmologist (eye specialist) - Ask me!
Glaucoma Australia RANZCO Glaucoma Foundation World Glaucoma Association
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