education

Important message for glaucoma patients

It is important for you to get yourself regularly screened for glaucoma.

 If you have been diagnosed to have glaucoma, effective treatment options are now available and regular treatment and follow up can help you to preserve your vision for your lifetime, avoiding unnecessary fear of going blind.

You can live happily with glaucoma and enjoy an excellent quality of life, particularly if the disease is detected early and treated in time. Always remember that once you have glaucoma, you will have to be under the care of an eye doctor for the rest of your life.

About Glaucoma

What is Glaucoma?

Glaucoma is a disease of the optic nerve of the eye, which is basically the structure that relays what the eye sees to the brain. The major risk factor is represented by the intraocular pressure (IOP). When elevated high, above normal will damage the optic nerve. If left untreated, continued damage to this structure may lead to visual field defects, visual impairment and blindness.

How does glaucoma damage occur?

The eye contains a fluid known as aqueous humor that provides nourishment to its internal structures. This fluid is produced behind the iris (colored portion of the eye) and then is drained out through a sieve-like structure called the trabecular meshwork at the front part of the eye.  In some eyes, abnormalities in the drainage system leads to impairment of ocular inside fluid outflow, and IOP increases. This high IOP may damage the optic nerve head located in the back part of the eye responsible for the vision. This condition is known as glaucoma. In other cases, IOP may be relatively normal, but glaucoma occurs due to inability of the eye to handle that normal mechanical stress, or because of poor blood supply to these same nerve fibers.

Glaucomatous optic disc

In glaucoma, the optic nerve gets damaged. A portion of the optic nerve may be assessed during the eye exam, where it can be seen as a round structure (optic disc), with the pink or reddish section representing the neural tissue that takes the visual information to the brain. The whitish central part represents absence of neural tissue, and it is called the “cup”. Some amount of cupping is normal, but excessive cupping, or an increase in the amount of cupping over time, suggests glaucoma. There are many blood vessels that emerge from the optic disc to the retina.
Glaucoma causes loss of the neural reddish tissue and there is progressive cupping of the optic disc – enlargement of the whitish central part.

How does glaucoma evolve?

The great majority of glaucoma cases evolve silently, as patients may not notice vision loss until it is significant and present in both eyes, or may assume that vision loss is correctable, as it is for other conditions such as cataract. When the disease is at advanced stages, most patients will then perceive visual abnormalities. Glaucomatous damage to the optic nerve is irreversible, so what is lost cannot be recovered.
The asymptomatic early stages of disease and irreversible nature of the glaucoma makes it one of the main causes of blindness worldwide. Glaucoma does not have a cure, however, this disease can be treated and the worsening of glaucomatous damage can be limited or even stopped. Thus, an early detection associated to an appropriate treatment and follow-up can preserve your vision throughout your lifetime.

Statistics

  • Glaucoma is the most common cause of irreversible blindness.
  • Based on prevalence studies, it is estimated that 79.6 million individuals will have glaucoma in 2020. This number is likely to increase to 111.8 million individuals in 2040.
  • At least, half of those with glaucoma are unaware that they are affected. In some developing countries, 90% of glaucoma is undetected.
  • In many cases, glaucoma may be asymptomatic.
  • It is estimated that more than 11 million individuals will be bilaterally blind due to glaucoma in 2020 (around 13% of the cases).
  • In most cases, blindness can be prevented with appropriate control and treatment.
  • In the USA, blindness is the third most feared health problem, after cancer and cardiac attacks.
  • Unfortunately, many individuals are unaware of the existence of glaucoma.
  • A better awareness could prevent visual disability in many people.

Drainage system of the eye

The eye contains a fluid known as aqueous humor that provides nourishment to its structures. This fluid is produced by the ciliary body (located behind the iris) and then flows between the iris and lens, through the pupil to the anterior part of the iris where is drained out through a sieve like structure called the trabecular meshwork, at the anterior chamber angle (located at the merging of the cornea-sclera with the iris periphery).
Many (but not all) cases of glaucoma occur due to a sufficiently elevated IOP, caused by impairment of the normal aqueous humor drainage.

Types of glaucoma

Glaucoma may be classified according to different aspects. Mainly:

According to the age of the patient:

  1. Congenital and developmental (from birth to 10 years) – Congenital glaucoma
  2. Juvenile (10 years to 35 years) – Juvenile glaucoma
  3. Adult (after 35 years)

According to the cause:

  1. Primary: Non-identifiable cause, occurs in susceptible individuals.
  2. Secondary: occurs due to other causes such as after trauma, drugs, other ocular diseases, intraocular surgeries, etc. – Secondary glaucoma

According to the site of obstruction of drainage system of the eye:

  1. Primary open angle glaucoma – Open angle glaucoma
  2. Primary angle closure glaucoma – Angle closure glaucoma

Are there any symptoms of glaucoma?

Glaucoma is known as the “silent thief of vision” and is typically associated with painless and progressive loss of vision that may not produce any symptoms. Usually, peripheral vision is affected with relative sparing of central vision at early stages of disease, and when the disease gets to advanced stages, the central vision is more severely affected. Glaucoma patients may notice that they cannot see objects at their side (due to loss of peripheral visual field), but largely the patients are not able to detect any symptoms until a very advanced stage. Sometimes, patients may notice or describe that their vision has become foggy (see How does glaucoma evolve?).

Angle-closure glaucoma may be associated with redness, pain in the eye, headache, blurred vision and coloured haloes around light bulbs – acute angle closure attack presenting with quite high IOP levels (above 40 mmHg). However, most angle closure glaucoma cases evolve asymptomatically, as the clogging of the drain and IOP rise tend to occur in a slowly progressive way (see Angle closure glaucoma).

Non-specific vision symptoms may also be associated with glaucoma, like cloudy/foggy vision, glare, or needing more light to read.

Congenital glaucoma

Glaucoma may occur in babies due to abnormal development of the internal drainage system of the eye. Its signs and symptoms are usually different than adult glaucoma. Classical cases present with enlarged eyes, with a whitish-bluish cloudy appearance as the cornea becomes edematous due to the high IOP. The baby will present intense photophobia (intolerance to light), blepharospasm (i.e. keep eyes shut when exposed to sunlight), and excessive tearing (which may be present in other abnormalities such as nasolacrimal duct obstruction).

Congenital glaucoma is a sight-threatening disease, and a consultation with a glaucoma specialist should be arranged as soon as possible. Examination under anesthesia is required for appropriate assessment of the condition, and treatment is primarily surgical. Early diagnosis and proper treatment are important for a good visual prognosis.

Long-term follow-up is necessary, when the IOP and optic nerve will be monitored, but also, glasses and eye-patching might be necessary for the development and maintenance of a good vision.

Juvenile glaucoma

Normally, glaucoma affects individuals after 40-50 years of age, but it may occur in younger ages.
Juvenile glaucoma affects teenagers or young adults and its signs and symptoms are very similar to adult glaucoma. However, juvenile glaucoma may be considered more visual threatening as IOP levels tend to be higher and also, as the disease onset is early in life, there is a need to preserve the optic nerve for a much longer period of time.
Therefore, although it is not a common disease, all individuals attending an ophthalmological check up should undergo IOP measurement and optic disc evaluation.

Open angle glaucoma

As in all forms of glaucoma, the end-organ damage is the optic nerve head. A sufficiently elevated IOP will damage the optic nerve, which is the structure that connects what the eyes see to the brain.

The “angle” is the part of the eye where the iris meets the cornea and the sclera. The drainage system of the eye is located at this region – trabecular meshwork, which consists of multiple layers of collagenous connective tissue. The trabecular beams form a net like structure that creates layers with large and small spaces within the beams.

The open angle glaucoma, as the term suggests, is characterized by an open angle. Nothing obstructs the flow of the aqueous humor to get to the trabecular meshwork, however, abnormalities within the spaces of the trabecular meshwork system lead to increase of the resistance to flow of fluid. The fluid pressure within the eye (IOP) gets elevated, and usually without any symptoms, gradually damages the optic nerve.

Ocular hypertension

This condition occurs in eyes with elevated IOP, without optic nerve damage. Due to individual characteristics that determine a decreased susceptibility to the disease, these eyes do not develop glaucoma. This may be partially explained in some cases due to an increased central corneal thickness (thick cornea), which may lead to imprecise measurement of the IOP by tonometer devices (overestimation of the IOP).

However, it is important to note that some eyes with elevated IOP may be simply at the beginning of the disease process, whereas there was not enough time to damage the optic nerve head. If this is the case, with time, glaucoma will develop.

The ophthalmologist will discuss with the patient the advantages and disadvantages of different management approaches for this condition in each case, including observation only or treatment.

In all Ocular Hypertension cases, continuous long-term follow-up are highly recommended, and some eye exams will be necessary for proper monitoring.

Glaucoma suspect

Glaucoma suspect is the term used for individuals in which glaucoma diagnosis cannot be confirmed but also cannot be excluded at the time of consultation. In these cases, a mid- or long-term follow-up associated with proper evaluation may be necessary to unveil the presence of disease.

Although this may be considered an uncomfortable situation, it is important to emphasize for the patient to remain calm, as the inability to establish the diagnosis usually occurs in early glaucoma cases and not in advanced cases in which the alterations are more evident.

The inability to confirm the diagnosis may be due to different causes.

The normal appearance of the optic nerve head shows wide variation in the normal population. And in some cases, it may be difficult to differentiate an early glaucomatous optic disc from an optic disc with an unusual appearance (but with no disease).

All individuals diagnosed as glaucoma suspects or with a positive family history of glaucoma should ideally perform proper documentation of the optic disc appearance and visual function status. These exams should be repeated periodically, in order to compare them for changes along mid and long-term follow-up. Along with other exams, determining the presence of deterioration of these variables with time will confirm (or not) the presence of disease.

The ophthalmologist will discuss with the patient the advantages and disadvantages of different management approaches for this condition. In all cases continuous long-term follow-up is highly recommended, and some eye exams are necessary for proper monitoring.

Angle closure glaucoma

As in all forms of glaucoma, the end-organ damage is the optic nerve head. A sufficiently elevated IOP will damage the optic nerve, which is the structure that connects what the eyes see to the brain.

The “angle” is the part of the eye where the iris meets the cornea and the sclera. The drainage system of the eye is located at this region – trabecular meshwork. (See Open angle glaucoma.)

In primary angle closure glaucoma, the part of the angle where the trabecular meshwork is located is closed/obstructed by the peripheral iris. This angle closure leads to IOP rise and damage to the optic nerve. Angle closure glaucoma usually affects anatomically “small eyes” – in which intra-ocular structures within a limited space area results in a crowded anterior segment.

It typically affects more women than men, and although it may occur in any individual, it is more common in some ethnic groups (i.e. Chinese). Most of the cases are asymptomatic, but some show quite intense symptoms. (See Acute angle closure.)

The most common mechanism of angle closure is called pupillary block, and it occurs due to relative block of fluid flow at the level of the pupil (from the posterior to anterior part of the eye), which makes the pressure at the posterior chamber to increase, leading to a forward bowing of the iris and narrowing of the angle

Differentiation between an open angle and a closed angle glaucoma is important because the treatment approach differs, as we may use additional procedures to treat angle closure glaucoma when compared to open angle glaucoma cases.

Acute angle closure

There is a form of angle closure that is very aggressive and shows intense symptoms. In this condition, there is a sudden rise in pressure leading to severe eye pain (and around the eye), redness, decrease in vision. This is known as an acute attack of angle closure and represents a medical emergency, which, if not treated in time, can cause optic nerve damage and loss of vision.

Acute attack symptoms normally occur in one eye, but it may be present in both eyes at the same time. The duration of the symptoms is relatively long (hours), when both pain and decrease vision are often associated. The pupil is often mid-dilated, and the pupil reflex is unresponsive to light.

Episodes of isolated eye pain or isolated blurred vision (minutes) that resolve spontaneously are likely not an acute angle closure attack.

Treatment may include topical and systemic drugs to lower IOP, followed by laser treatment aimed to open the angle (See Laser peripheral iridotomy). In some cases, surgical procedures may also be used to treat this condition.

Secondary glaucoma – Can diabetes cause glaucoma?

Neovascular glaucoma

This is an aggressive form of secondary angle closure glaucoma. It usually affects individuals with retinal disease, mainly retinal vascular occlusion or uncontrolled diabetic retinopathy. The primary abnormality is represented by the retinal ischemia, which releases angiogenic factors. These factors create new vessels at the anterior chamber, usually at the iris pupillary border and the angle wall. These new vessels are abnormal and fragile and will cause a series of events which will lead to secondary angle closure (drainage system obstruction).

The treatment strategy should aim at the primary abnormality (retinal ischemia) and also at the IOP control. This relatively complex form of glaucoma often requires the combined efforts of glaucoma and retina specialists. Diabetic patients should try to maintain as good control of their disease as possible.

Secondary glaucoma – Can medications cause glaucoma?

Yes, glaucoma can be caused by several medications taken for other diseases, such as Parkinson, epilepsy, depression, allergies, prostate disorders, etc. These represent secondary glaucoma cases.

Particular attention should be given to corticosteroids. Steroid induced glaucoma is a type of glaucoma which develops with the use of medicines known as corticosteroids. It is most commonly noticed with steroid eye drops taken for allergic conjunctivitis/uveitis but can occur with use of steroid containing inhalers (taken by patients who suffer from asthma), nasal spray, skin ointments and any oral or IV medication containing steroids. Moreover, not only corticosteroids may cause glaucoma, but it may also lead to loss of IOP control in patients in treatment for glaucoma.

Thus steroids should be used cautiously and the patients who are using any form of steroid therapy must consult their ophthalmologist (eye specialist) and have their IOP checked regularly.

Of note, particularly for angle closure glaucoma, there are many medications that may trigger or contribute to the angle closure process. Drugs used for depression, migraine, urine incontinence, gastrointestinal disorders and other health conditions can worsen or cause a closed angle. Thus, patients with this form of the disease or suspect of having it should always mention it to their physicians, who will be able to evaluate which medications are safe or not. Also, patients with untreated angle closure or “occludable angles” should be careful when using some medications, even over the counter medications.

Secondary glaucoma – Can glaucoma occur after injury (trauma) to the eye?

When an eye sustains an injury there can be an acute increase in IOP due to damage to the angle structures, hyphema (blood in anterior chamber), inflammation, and other mechanisms. The more severe the trauma, the greater are the chances to develop glaucoma and other ocular complications. But IOP increase may also occur later in life due to damage of the trabecular meshwork. This form of glaucoma can occur even up to 10-20 years after injury. These are also considered secondary glaucoma cases.

It is recommended that any person who has sustained an injury to the eye should get him/herself evaluated for glaucoma, and maintain regular follow-up with an ophthalmologist.

What are the tests done to diagnose glaucoma?

Glaucoma is diagnosed by performing the following 4 essential tests:

  1. Measurement of intraocular pressure with a tonometer (see How is tonometry done?).
  2. Gonioscopy to view the drainage angle (trabecular meshwork) and see if it is open or closed (see How is gonioscopy done?).
  3. Examination of the structure of the optic nerve (see How is the optic nerve examined?).
  4. Evaluation of function of the optic nerve (visual field / perimetry) (see How is the visual field examined?).

In addition to these basic exams, additional tests that may be performed include:

  • Pachymetry (corneal thickness): helps interpret eye pressure measurements.
  • Special visual field tests (Frequency doubling / Short wave perimetry): to assess different aspects of visual function.
  • Imaging of the optic nerve and retinal nerve fiber layer with machines such as the HRT, GDx or OCT: to assess and quantify the presence of glaucomatous structural damage.
  • Additional evaluation of the angle with Ultrasound biomicroscopy (UBM) / anterior segment optical coherence tomography (ASOCT) Of note, these exams are required in just a few cases, as usually gonioscopy exam is enough to evaluate the angle

How frequently should I get my eyes examined?

If you have been diagnosed with glaucoma you will require a 3-12 monthly follow-up, depending on the severity of disease, the IOP levels under treatment, and other risk factors. The more severe the disease, the more frequent the follow-up. On the other hand, once the disease is well under control and there are no signs of progression, follow-up at longer intervals may suffice.

The bottom line is that the recommended interval between consultations may vary, and should be determined by your ophthalmologist. Of note, glaucoma patients will need follow-up visits for the entire life.

After the initial diagnosis, you will have to get the visual field test repeated to get a good baseline and then repeated more frequently in case the disease is advanced or if your pressure is not under adequate control.

After initial diagnosis, all individuals with glaucoma should perform proper documentation of the optic disc appearance and visual function status. Visual field tests often need to be repeated to get a good and consistent baseline. These exams should then be repeated periodically, in order to compare them for changes along mid and long-term follow-up.

Will glaucoma therapy improve my vision?

No. Unfortunately glaucoma medicines, laser or surgery cannot improve your vision but can prevent you from further visual loss.

What is the treatment of glaucoma?

Glaucoma treatment aims to control the intra-ocular pressure and halt glaucoma progression. It is important to understand that glaucoma cannot be cured and whatever damage has occurred to the optic nerve cannot be reversed. However, it is possible to maintain current vision (central and peripheral), so the patient will not develop further visual damage.

Various modalities of treatment are available today. These include:

  1. Eye drops – see Eyedrop glaucoma treatment
  2. Systemic medications (Tablets and endovenous medication) – see Systemic glaucoma treatment
  3. Laser surgery – see Laser glaucoma treatment
  4. Incisional surgery – see Glaucoma surgeries

Eye drop glaucoma treatment

Eyedrops are usually prescribed as the first line therapy for most types of glaucoma. It is essential to understand that glaucoma does not have a cure, so these drops should be taken on a regular basis, everyday, for your entire life. One of the most important factors in using eye drops for glaucoma is regularity over a long period of time. Consistent/Repetitive failure to comply with eyedrop treatment may result in poor glaucoma control and vision loss.

As a suggestion, you may plan out a schedule for taking your drops around your normal routine, such as when you wake up, brush your teeth, eat meals or when you go to bed at night. You may also set reminders in your cell phone. As a suggestion, after taking a dose, you can put a mark on the calendar so that you remember that you have taken the medicine.

Aim to put only one drop at a time, but if you are not sure the drop got into the eye, you may put an extra drop right away. To optimize eyedrop use, please check What is the correct way of instilling the eyedrops?.

It is recommended to keep a stock of your medication at home, and do not forget to take your eyedrops bottles with you while travelling. Before you visit your eye doctor for check up, always use your eyedrops as usual.

Eyedrops are medicines, and it may be contra-indicated in the presence of some other systemic/ocular diseases. Please remember to tell your doctor if you suffer from any other medical illness like asthma, arrhythmia, bradycardia, diabetes, hypertension, thyroid diseases, angina, arthritis, depression etc., or are taking oral medicines or inhalers for any other condition. The ophthalmologist is able to choose the best treatment strategy for each individual case.

What should I do if I forget to take my eyedrops?

One of the most important factors in using eye drops for glaucoma is regularity over a long period of time. Forgetting to put your eye drops may happen once in a while, but consistent/repetitive failure to comply with eye drop treatment may result in poor glaucoma control and vision loss.
If you forget to take a dose of your eye drops, it is best to instill the drop as soon as you remember it. If the next dose is due shortly, wait for the usual time to use it.

Laser glaucoma treatment

Laser is the treatment of choice for angle closure glaucoma and other types of laser may also be performed for open angle glaucoma. Lasers can be performed as an outpatient procedure in a few minutes and may be used to reduce the IOP.

The following types of laser procedures are generally used in glaucoma:

Glaucoma surgeries

The failure of medications and laser surgery to control the intraocular pressure (IOP) and consequently glaucomatous neuropathy, is an indication for surgery. Surgery may also be performed if the patient has allergy to the drugs, is not compliant to therapy or the disease continues to progress despite treatment. Advanced disease and other conditions are also indication for surgery and the ophthalmologist will discuss the best possible treatment options with the patient.

Stem cell transplant for glaucoma treatment

Can stem cell transplant be done to repair the damaged optic nerve in glaucoma? This is an area of experimental research and until now this treatment is not possible/available for glaucoma patients. However, there are several research groups working on this topic at this moment, and

Changes in life-style for glaucoma treatment

If one has glaucoma, are there any changes in life-style which can help to control the disease?

  • A healthy body is good for a healthy eye, but there is no strong evidence of any life-style changes specifically aimed to improve glaucoma control/prevention.
  • Consumption of food rich in Antioxidants (green leafy vegetables, salads) is good for the body in general.
  • There is some evidence that wearing a tight neck tie may elevate the eye pressure.
  • Drinking large amounts of any liquid within a very short time can also increase eye pressure. Patients with glaucoma may drink plenty of fluids (healthy habit), but they should drink them in normal amounts over the course of a day.
  • All systemic diseases like diabetes and hypertension should be well controlled in consultation with a qualified physician.
  • Patients who are on anti-hypertensive should not have a very low blood pressure, as low blood pressure may be harmful for glaucoma.
  • Glaucoma patients can do all physical exercise (particularly aerobic exercise), which may protect against glaucoma. Yoga is acceptable but one should avoid exercises with head down postures like shirshasana/sarvangasana (yoga positions) as these can cause an increase in Intraocular pressure.
  • Meditation and relaxation exercises can help reduce the stress and anxiety in glaucoma patients and their caregivers.
  • Quit smoking is good for the body in general.

Who should be checked for glaucoma?

  1. In general, all individuals between 35-40 years should undergo an eye examination, which should include IOP measurement and examination of the optic nerve head. In general, after the age of 40 years, check up should preferably be done every 2-3 years and 1-2 years check up is advised after the age of 60 years. The appropriate time intervals between check-ups may vary, please discuss this with your ophthalmologist.
  2. All individuals with a positive family history of glaucoma should undergo comprehensive eye examination, and maintain follow-up at regular intervals. It does not mean all siblings will have the disease, but siblings of glaucoma patients have up to 10 times the risk to develop glaucoma as compared to the normal population.
  3. Patients with diabetes and systemic hypertension also need regular check up for glaucoma.
  4. During routine visits, your eye doctor may be able to identify additional risk factors for glaucoma development, such as: (i) a thin cornea, (ii) being very nearsighted or very farsighted, (iii) having intraocular pressure measurements above 22 mmHg, or (iv) having a narrow angle or narrow anterior chamber. These factors may increase your risk of glaucoma and hence may require closer follow-up. Individuals with African ancestry may be at higher risk for open angle glaucoma, and those with Chinese ancestry may be at higher risk for angle closure glaucoma.

How can the family help?

Patients who have lost vision progressively due to glaucoma will be under great psychological stress, and caring to the needs of the patient may be challenging both to the doctor and family members. The family can help in multiple ways:

  1. Organize the main household items, which are of daily use so that they can be easily located and identified by the patient. As a suggestion, identify important items with high-contrast labels.
  2. Remove all items in home that could make the patient trip over- any small stools, tables, loose wires, etc.
  3. Program important numbers like that of police, ambulance, fire station, etc. in your phone with voice activation.
  4. Put different number of rubber bands over your various medications so that it can be identified.
  5. Add more lights in your house as better illumination can provide better mobility.
  6. Carry list and timing of medications in your wallet or purse or keep an alarm in your cell phone to remind the patient to use eye drops regularly.
  7. Help the patient by bringing him/her regularly to the hospital for check-up.
  8. Above all provide the moral support to the patient and encourage community-based rehabilitation with vocational training to overcome the impact of disability.
  9. Get all family members screened for glaucoma.
  10. Spread the message for glaucoma screening in the community.

What can be done for blind or low vision patients?

After a proper assessment by an eye-care professional, specially qualified in providing low vision services the following aids can be advised to the patient:

  1. Devices with large letters and numbers: recently there are a variety of items manufactured for helping out visually handicapped patients. There are watches, clocks, telephones, calendars, newspapers with large prints, which helps visualization.
  2. Computer modification: The letters on computer screen can be modified by increasing the size and contrast, so as to aid visualization.
  3. Audio enhancements: There are also devices that talk, like talking books, calendars, calculators etc. The computers also have audio aids and speech synthesizers which convert spoken words into text format.
  4. The other low vision aids that can be prescribed are magnifying glasses with or without illumination, spectacles mounted telescopes, CCTV magnifier etc.