What is Glaucoma?
Glaucoma is the name given to a number of conditions in which the optic nerve (the nerve which carries images to the brain) is damaged where it leaves the eye. This type of damage has characteristic features and effects on vision. The cause of this damage in children is almost always raised pressure within the eye (intraocular pressure). This rise in pressure can be caused by other problems affecting the eye such as inflammation. These are called secondary glaucoma. Glaucoma which forms during the early years of a child's life is called developmental or congenital glaucoma. The glaucomas that affect babies and children are rare (about 1 in 10,000 births).
What controls the pressure in the eye?
The eye is like a football. It pumps itself up with a watery fluid (aqueous humour) secreted by the part of the eye called the ciliary body. This is a ring of tissue just behind the coloured part of the eye (iris). The iris divides the compartment at the back of the eye, called the posterior chamber (not to be confused with the vitreous compartment which is behind the lens) from the small compartment at the front, which is called the anterior chamber. Aqueous humour flows from this ring of tissue through the gap (pupil) in the iris into the front portion of the eye.
The clear window in the front portion of the eye is called the cornea and is like a transparent dome; a filter system runs right around the base of the dome in the drainage angle. The aqueous humour flows out through this filter system (the trabecular meshwork) into a collector channel called Schlemm's canal and then into the blood vessels around the outside of the eye. It is the resistance of the filter system that determines the pressure in the eye. In the vast majority of children with glaucoma, the pressure goes up in the eye because this drainage system does not work properly. This blockage can happen in many ways, as will be explained later.
What types of glaucoma can children have?
Glaucoma in babies and children is also known as developmental glaucoma.
Glaucoma can sometimes occur in children with other conditions such as aniridia, in which there is no, or very little, development of the iris.
Glaucoma following cataract surgery
Glaucoma can also follow cataract surgery in children. If the lens of the eye becomes cloudy, this is called a cataract and may require surgery. This type of glaucoma occurs particularly when the cataract surgery has taken place very early in life. The reason for the development of glaucoma after cataract surgery is still not entirely clear.
Glaucoma can also occur if the eye becomes inflammed for any reason, such as in children who have the childhood form of arthritis, as the drainage system may get blocked with inflammatory cells.
Sturge Weber Syndrome
Glaucoma can also occur in Sturge Weber syndrome; these patients also have a blood vessel birth mark on the face, particularly the forehead, known as a port wine stain. Children with these physical signs need to be monitored for the development of glaucoma and treated if necessary.
Primary congenital glaucoma
This is the most common type of glaucoma in small children. The normal drainage channel in the eye (the trabecular meshwork) does not develop as it should, and as a result the aqueous humour does not flow out of the eye properly and the intraocular pressure in the eye rises.
Generally speaking, the majority of cases of this type of glaucoma are genetic in origin, but because of the type of inheritance (recessive) most families will have no family history of the condition. Ongoing research is increasing our knowledge rapidly and specific advice on the chances of inheritance should be sought from an expert with up to date knowledge if further babies are anticipated or for prospective parents who already have the condition themselves.
Axenfeld's or Reiger's Anomaly
These conditions are named after the doctors who first described them. In this type of glaucoma, apart from the problem with the development of the filter system, there are also usually abnormalities in the development of the iris and sometimes in parts of the cornea. In addition there can be changes in the shape of the teeth, face, ears and other parts of the body, although these changes may not be present.
Glaucoma may not develop in some patients who have the eye changes, but as there is a significant chance of developing glaucoma, patients with Axenfeld's or Reiger's Anomalies need to have regular check-ups for life.
In this condition there are abnormalities in the lens of the eye. Sometimes the lens of the eye continues to be attached to the cornea. Glaucoma may develop and further treatment, such as surgery, may be required.
The symptoms of glaucoma in babies and children are:
The outer coat (sclera) of a child's eye is much softer and more flexible than that of an adult. As a result, if the pressure rises in the eye, the eye expands rather like a balloon being blown up. This gives rise to the old-fashioned name for childhood glaucoma, buphthalmos, a name which likens an eye with glaucoma to the eye of an ox, which is much larger than a human eye. This enlarged eye size is one of the best indications of raised eye pressure in a child. Reducing the pressure does not usually bring the eye back to its normal size but may reduce the size of the eye very slightly. Some parents of children with glaucoma report how people have tended to remark on what lovely large eyes their child has.
Sensitivity to light
Children with raised intraocular pressure often become very sensitive to light. There may be several causes for this. The clear window of the eye (cornea) may be slightly waterlogged and cloudy, which can be uncomfortable. When the cornea is not absolutely clear, light bounces off the cornea irregularly and causes glare. It will not harm the child's vision in the short term to wear dark glasses, particularly in bright lighting conditions. Even after the pressure is lowered, some degree of sensitivity to light may persist in the long term.
The cornea has little cells on the inside which pump aqueous humour out of the cornea, keeping it clear. If the intraocular pressure rises sufficiently, aqueous humour is pushed into the cornea, making it waterlogged and cloudy. If the cornea expands, small cracks may occur on the inside of the cornea and this may also cause partial clouding. The clouding clears when the pressure is reduced but this may sometimes take several months or more.
Watering is a natural response to any form of irritation of the eyes. If the eye pressure is high, and if there is glare from lights and also some swelling of the cornea, then the natural reflex will be watering of the eyes. This should improve when the pressure in the eye is controlled.
Poor vision and jerky eyes (Nystagmus)
Occasionally, if raised pressure in the eye has caused clouding of the cornea or pressure on the optic nerve (the nerve that conveys sight to the brain), vision may be poorer than usual and there maybe also slightly jerky movements of the eye. After treatment, most of these symptoms improve.
In some children the eye with poorer vision may be seen to turn inwards, towards the nose, or outwards.
1. Examination under anaesthetic (EUA)
Most babies and children initially have to be examined under anaesthetic. If their eye pressure is found to be raised, then surgery will usually be carried out at the same time to save a further anaesthetic. Every time a child is examined under anaesthetic, there is a chance that a further procedure may be required and parents should be aware of this. Generally speaking, a child can be examined without anaesthetic after the age of 5 years, but this can vary.
This is often the first operation to be performed. A very fine scalpel is introduced into the front chamber of the eye and an incision made into the filter system. This is to open up the channel that did not open properly as the eye developed. The operation has to be done using a special lens called a gonioscope to view the inside of the eye. To get a good view sometimes the superficial skin layer of the cornea (epithelium) needs to be removed. This rapidly re-grows and heals within a day or two. However, during this period, the eyes will be uncomfortable and the child may not sleep well because of the discomfort. Painkilling syrup (paracetamol, CalpolTM) may be prescribed. If this operation is performed, both eyes will be done at the same time. In the majority of cases this operation lowers the intraocular pressure, but a second goniotomy may be required if the lowering of pressure is not sufficient.
Another operation to create a new drainage channel (trabeculectomy) may be required if the eye does not respond to a reopening of the channels internally.
In this operation, a very fine probe is threaded into the main collector channel (Schlemm's canal). This delicate probe is pushed through into the front chamber of the eye, creating a new drainage channel. This operation is used in certain types of glaucoma or when the cornea is not clear enough to perform a goniotomy. It can be combined with a trabeculectomy, where another new drainage channel is made in the eye.
If one eye is found to be lazy after examination, then patching treatment may be required.
This involves putting a patch on the good eye to force the weaker eye to work harder. A lazy eye occurs because the brain prefers to receive the signal from the better eye and switches off the connections to the weaker eye. If this is allowed to happen, normal connections between the weaker eye and the brain do not form and the vision in the eye is reduced, even though the eyeball itself may be in perfectly good condition. The patching treatment forces the brain to develop connections to the weaker eye. It is extremely important to persist with this patching treatment, as once the pressure is controlled, a good balance between the eyes may be the single most important factor in determining whether the eye sees well or not.
This is when an entirely new drainage channel is made in the eye. A small flap is created by the surgeon, usually in the part of the eye just underneath the upper lid. This flap is secured with extremely fine stitches and is covered with the white skin of the eye (conjuctiva). The fluid accumulated underneath the skin of the eye then flows out of the eye and gets absorbed into the blood vessels surrounding the eyeball.
Following the operation, a tiny bump (known as a bleb) can sometimes be seen under the upper lid. This is a small collection of fluid draining away under the skin of the eye.
In some children a special drainage tube has to be inserted into the eye, to drain fluid out to a reservoir at the back of the eyeball. The reason for using this tube is that, in certain circumstances, it works better than the flap valve that is created during a trabeculectomy, and it will stay in the eye for an indefinite time. Anti-scarring treatment is used and a small stitch is sometimes left in the eye to control the amount of flow going through the tube. This stitch can easily be removed if the eye pressure rises in the future. Sometimes, one or two weeks after surgery, it may be necessary to put gas or jelly into the eye to adjust the pressure if it has got too low.
The child will not 'outgrow' the tube and some people have had them implanted for over 25 years.
Occasionally a small amount of scar tissue forms around the operation site in trabeculectomy, or even after a drainage tube is implanted. This can sometimes be released by loosening some of the scar tissue with a very fine small needle (this procedure is called needling). After this procedure is carried out, anti-scarring treatment can be given, and sometimes a jelly-like substance is used to increase the effect of the anti-scarring injection. This jelly may occasionally be visible as a transparent lump in the eye which disappears after a few days.
Sometimes laser treatment is recommended. In this special form of laser treatment, an invisible laser is shone through the white coat of the eye onto the ciliary body (the tissue which produces the aqueous humour within the eye). This produces very small burns in the ciliary body and reduces the amount of aqueous humour the eye makes, resulting in a fall in the pressure of the eye. This is a relatively gentle treatment, but it often needs to be repeated several times. Sometimes the eye is a little red and inflamed after the procedure and steroid drops are required. Very occasionally, tablets which act like aspirin may be needed to reduce the inflammation after the laser treatment. It is usually necessary to continue treatment with eye drops and repeat laser treatments may be required.
3. How good will my child's eyesight be after treatment?
It is extremely difficult to give a definite prediction of how good a child's eyesight will be after treatment, especially when the child is very young. Many children with glaucoma who have been treated do have excellent vision in adult life and many of them have effectively normal vision. However, the most important thing is control of the intraocular pressure and then, following that, further treatment if necessary with glasses and patches to ensure that the vision develops normally. As the child grows older the specialist will have a better idea of how good their long-term vision will be.
Following successful treatment, the child will need to return to the clinic at regular intervals for check ups. In fact, children with glaucoma need to have their condition monitored for life.
4. Anti-scarring treatment
The main problem with these operations is scarring. Young eyes heal especially well and scar tissue can form, which may block the flow of fluid out of the eye. This results in a further rise in eye pressure. However, new successful methods have been devised to help prevent this happening and these have considerably improved the results of surgery. Some of these treatments may include beta-radiation, 5-fluorouracil and mitomycin-c.
Very tiny doses of these agents localised only to the treatment area (an area a quarter to a half the size of your little fingernail) are used to improve treatment.
During the anaesthetic, or later on in the clinic, the power of the eyes will be checked. This can be done while the child is asleep by using a series of special lenses and a light which reflects off the back of the eyeball (retinoscopy). In older children this can be done in the clinic. If it is found that glasses are needed, these will be prescribed. Sometimes glasses need only be worn during the patching treatment, and sometimes they will be dispensed for continuous wear. If necessary, a pair of tinted glasses will also be dispensed for use in bright light because of the sensitivity to light found in many children with congenital glaucoma.
How do I deal with my child's medications and treatment?
1. How do eye drops work?
There are many types of eye drops. Those that are given for eye pressure work in two main ways: by reducing the amount of aqueous humour formed in the eye (like turning off the tap slightly) or by opening the drainage channels (unblocking the drainpipe).
2. What drops and tablets can be used to treat glaucoma?
Beta blocker eye drops
e.g. Timoptol, Timoptol LA, Nyogel, Betagan, Betoptic, Teoptic
These drops reduce the amount of aqueous humour produced by the eye. They are usually used twice a day, although they can sometimes be prescribed for use once a day. Occasionally these eye drops may cause problems with breathing or slow the heartbeat. If your child has asthma, any other breathing trouble or heart problems, you must advise the doctor. If your child develops symptoms such as wheezing or coughing at night, contact the doctor as their eye drops may have to be changed.
These eye drops are used to increase the amount of aqueous humour that flows out of the eye. They usually have to be used three to four times a day, unless combined with other drops. Pilocarpine can sometimes be given in an ointment form (Pilogel) once at night. These drops may give rise to a little stinging and a slight aching around the eye for some minutes after they are used. Older children may say that their vision becomes blurred for a little while, as the drops make the eye focus for close vision.
If your child notices flashing lights or floaters (specks moving across their vision) after these drops, you must let your specialist know straight away.
Topical carbonic anhydrase inhibitors
e.g. Trusopt, Azopt
These eye drops reduce the pressure in the eye by reducing the amount of aqueous humour produced by the eye. These drops usually have to be used three times a day, although they can be prescribed for use twice a day in combination with other drops. These drops are relatively new and they are the eye drop form of the tablets that are also used for glaucoma.
Alpha adrenergic stimulants
e.g. Iopidine, Alphagan
These drops reduce the amount of fluid produced by the eye. They have to be used twice a day.
Children may occasionally feel dizzy, tired or develop nightmares on these drops, and if so you must contact the specialist immediately.
e.g. Xalatan, Lumigan Travatan
These drops increase the flow of fluid out of the eye. After prolonged use, they may make the coloured part of the eye (iris) darken in a few patients who have light-coloured eyes. This change occurs slowly, but is permanent.
Antibiotic eye drops
e.g. Chloramphenicol, Gentamicin, Exocin
These antibiotic eye drops are generally used after surgery to prevent infection. They are normally stopped after a few weeks, but may occasionally be continued for longer periods.
Steriod eye drops
e.g. Maxidex, Predsol 1% Forte, Predsol
These eye drops are usually used to prevent inflammation and redness of the eye after surgery. They also help to prevent scarring and are used for several months after surgery, or for a week or two after laser treatment.
Occasionally tablets are used to reduce the pressure in the eye. These tablets (Diamox) are very strong and reduce the pressure considerably. However, they can have many side effects and these include tingling fingers, poor appetite, skin rashes, bed wetting at night, occasional behavioural disturbance and in a few patients in the long-term, kidney stones.
3. What is the best way to put eye drops in my child's eye?
When drops are first prescribed, you will be shown how to put them in. Often it is easier to wait until a baby is asleep before putting drops in the eye. It can be helpful with a small baby to wrap him/her tightly in a blanket so that you can concentrate on opening their eyelids rather than keeping little arms and legs from knocking the bottle from your grasp.
Older children could stand, sit or lie whilst you pull down the bottom lid, making a pocket for the fluid to drop into.
4. How important is the timing of eye drops?
Drops only work for a number of hours. The precise amount of time varies depending on the type of eye drop. Putting in two drops of one drug will not work twice as well, and with some drops a small baby could be sick if you do this. If you have two different drops to use, wait a minimum of ten minutes, if possible, between drops. It is always best to ask the advice of your own specialist in order to make a daily timetable for inserting eye drops.
5. Do the drops hurt or sting?
Some eye drops sting a little. This usually lasts for less than a minute and feels rather like the smarting you feel when you accidentally get soap in your eyes. Some drops may cause an ache over the eye for a few minutes after putting them in.
6. Why do some eye drops leaflets advise that they are 'not to be used in children'?
This warning is given by the pharmaceutical companies (who cannot run drug trials on children), but in fact the drops may be used at the discretion of the eye specialist treating the child.
7. Do eye drops affect my child's vision?
Most of the eye drops used in children's glaucoma do not cause any blurring of vision.
8. How long will eye drops be needed?
This depends upon the reason why the drops are being used, e.g. for inflammation of the eye after an operation, for infection, or for glaucoma itself. The only person who can answer this question is your child's eye surgeon.
9. Can my child take tablets instead?
In a very small child it is hard to be sure how much of a tablet or medicine has been swallowed. Also, they can cause stomach upsets. A medicine taken by mouth is more likely to cause side effects than one applied directly to the eye.
For these reasons, tablets are rarely prescribed to children with glaucoma except, in some cases, for a few days before a surgical procedure.
10. Is it necessary to tell the eye specialist about other medical problems?
Always give the doctor as much information as possible about your child's state of health. In particular, they will find it useful to know about asthma, allergies and any heart or kidney problems. Likewise, the child's G.P. or doctors who are treating the child during a hospital stay should be reminded that the child takes glaucoma eye drops, particularly when they prescribe other medications.
11. How should the eye drops be stored?
Storage instructions will be printed on the leaflet enclosed with the drops – always read this. Generally speaking, a cool place below 25 degrees Celsius or in the door of the refrigerator is suitable. The pharmacist will advise you. Always keep them out of the reach of children. Eye drops are drugs and if swallowed can cause illness.
Once opened, drops should be thrown away after one month (even if the bottle is not finished).
Make sure that you have a new bottle ready to use if the doctor wants your child to use the drops continually.
What happens at follow up visits to the clinic?
This section will give you more information on what you can expect when going to the eye clinic and how glaucoma will be managed by the specialist.
How often should my child be checked?
The frequency of check-ups varies for each child and depends upon many factors. The specialist will decide.
What is the doctor looking for?
The child's vision will be assessed. The doctor or orthoptist will look for a squint (strabismus). They will also see if the eye has enlarged and whether there is any redness or clouding of the eye. If possible the pressure of the eye will be measured.
Why are drops put into the eyes when it is being examined?
Sometimes drops are needed to enlarge the pupil in order to see the retina and the head of the nerve of the eye (optic disc). These drops also make it possible for the doctor to test for spectacles.
Drops may also be used which contain local anaesthetic and a yellow dye (fluorescein).This enables the specialist to measure the pressure in the eye using a special instrument with a blue light.
At what age can my child be examined without anaesthetic?
This varies considerably. Many children by the age of 5 years will allow the specialist to check the eye pressure using the Goldmann tonometer (with a blue light). At younger ages, air puff methods of checking eye pressure may be helpful but are not always accurate for high pressures in large eyes. Sometimes a pen-like instrument (Tonopen) can be used.
Should parents and siblings of a child with glaucoma have their eyes checked too?
As some forms of glaucoma occur in families, the doctor will usually examine both parents and siblings when a child is diagnosed. It is very rare for the type of glaucoma found in children to be found for the first time in adults.
This is always a difficult thing for parents of children with glaucoma to judge.
Here follow some of the more commonly asked questions about helping a child to live with glaucoma.
Is my child in pain?
When a baby or young child develops glaucoma they are often miserable, and this is one of the concerns that first alerts the family and doctors to the problem. The baby may be crying a lot and feeding poorly, and the eye is red and watery. The baby is particularly upset by bright lights and may try to bury its head in the pillow. The colour of the eye may seem to change and the eyeball may become enlarged.
Will crying hurt the eye more?
For the front of the eye to stay healthy, it needs the moisture of tears. Tears contain natural antibiotics. Forming a lot of tears when a baby cries does no damage.
Should I worry if my child bangs their head?
Obviously a severe blow to the head could cause injury to any child and if there is any concern, seek a doctor's advice immediately. Minor knocks and bumps are a normal course of events in any toddler's life, but an enlarged eye is more fragile than a normal eye. If there is sudden marked changes in the vision or the eye looks cloudy, has blood inside or if the eye is causing the child pain, then seek medical advice immediately. If a child with glaucoma receives a hard knock directly on the eye (rather than on the head or face) then they should be examined by a specialist.
Can my child play sport, go swimming and so on?
If the eye has become greatly enlarged then it may easily be damaged by a direct blow. As this is the case, rough sports such as rugby are inadvisable. Protective glasses are available for ball sports, and are especially recommended for playing squash. In some cases, for example if your child has recently had eye surgery (especially if it is a trabeculectomy), you may be advised not to allow them to swim in order to avoid infection.
It is recommended that you seek the advice of your own surgeon regarding your child's individual needs.
Not all types of developmental glaucoma are hereditary. However, your family may find it helpful to speak to a genetic counsellor who will advise you on the possibility of a further child being affected by glaucoma and the risk to subsequent generations. This knowledge will also be helpful for your child in the future.