PAEDIATRIC GLAUCOMA
Glaucoma is the name given to a group of diseases in which the optic nerve is damaged. The cause of this damage in children is virtually always raised pressure within the eye (intraocular pressure). If the pressure occurs in children for no apparent underlying reason, the glaucoma is known as primary congenital glaucoma (PCG). If there is an identifiable underlying reason for elevated eye pressure, they are called secondary glaucomas.
Primary Congenital Glaucoma
This is the most common type of glaucoma in babies and children. The normal drainage channels do not fully develop so aqueous humour cannot flow out of the eye properly. Most types of congenital glaucoma are not inherited and so the risk of further children being are affected are small, although advice should be sought from your doctor.
Secondary Glaucomas
There are many different types of secondary glaucomas in children.
Axenfeld-Reiger Anomaly is a rare type of glaucoma where the front part of the eye develops abnormally. In addition, there can be other effects such as dental abnormalities and changes in the face. Glaucoma occurs in about half of people with this anomaly and follow up needs to continue for life. This type of abnormality is usually inherited.
Peter's anomaly is another developmental disorder where the cornea (the clear window of the eye) is also affected. Glaucoma may develop and often requires surgery.
Aniridia is a rare condition where the normal iris does not develop properly. This condition is usually inherited but can also occur sporadically. Glaucoma occurs in about half of affected individuals and often requires surgery. Children who are born with aniridia may also develop kidney problems and screening may therefore be required. Sturge-Weber syndrome is not usually inherited and results in a blood vessel birth mark on the face (port-wine stain). Children with
Sturge-Weber syndrome may also develop epilepsy and other neurological problems. Glaucoma can also follow cataract surgery in children (congenital cataracts). This type of glaucoma is known as
aphakic glaucoma and often needs either laser treatment or surgery.
Some children who develop inflammation within the eye (uveitis or iritis) can also develop glaucoma as the drainage system may get blocked with inflammatory cells.
SYMPTOMS AND SIGNS OF GLAUCOMA IN CHILDREN
Large eyes (Buphthalmos)
As the pressure in the eye builds up in children, the coats of the eye, which are softer than in adults blow up like a balloon. The enlarged eye is one of the best indications of raised eye pressure in a child. Reducing the pressure does not bring the eye back to a normal size but may reduce the size slightly.
Light Sensitivity (Photophobia)
Children with elevated eye pressure often become very light sensitive. This is often caused when the cornea becomes slightly 'waterlogged' as a result of the high pressure. Even when the pressure is well controlled, light sensitivity may persist.
Cloudy Eyes
When the cornea becomes waterlogged, as aqueous humour is pushed into the cornea, the cornea begins to look cloudy. This may occur suddenly and may be the first indication that there is glaucoma present. When the pressure is brought back to normal with treatment, it may take several weeks or months for the cornea to clear.
Watery Eyes
Watering is a natural response to any form of eye irritation. As the cornea becomes swollen, the natural reflex is eye watering. This should improve when the eye pressure is controlled
Glaucoma in Families
The majority of glaucoma in children is not inherited. Families with a history of childhood glaucoma should consult a specialist in children's glaucoma regarding the possibility of inheritance.
HOW IS GLAUCOMA IN CHILDREN TREATED?
Examination under anaesthetic (EUA)
Most babies and children are examined under an anaesthetic. If the diagnosis is confirmed and the eye pressure is found to be raised, then surgery is carried out at the same time. Children at the age of 5 years can usually be examined without the need for an anaesthetic.
SURGICAL OPTIONS
Goniotomy
This is often the first surgical operation that is performed in babies with glaucoma. A very fine scalpel enters the eye and an incision is made into the filtering system of the eye. This opens up the channels that have not developed properly. Occasionally it is necessary to scrape the cells from the front of the eye to get a good view to perform the operation. This rapidly regrows but may cause the child some discomfort for a couple of days. If the pressure does not reduce, a second goniotomy can be performed. If the eye does not respond to goniotomy surgery, another procedure may be required to create a new drainage channel (trabeculectomy).
Trabeculotomy
If the cornea is not clear enough to perform a goniotomy, a trabeculotomy can be performed in which a very fine probe is threaded into the main collector channel of the eye (Schlemm's canal). The probe is pushed through into the front chamber of the eye to create a new drainage channel.
Trabeculectomy
A small flap is created in the part of the eye just underneath the upper eyelid. In this procedure a completely new drainage channel is made. The fluid accumulates beneath the conjunctiva forming a 'bleb'. The main problem with this operation is that scar tissue can form, especially in young eyes and block off the drainage of aqueous humour. However, new techniques and the use of anti-scarring medicines used during the operation have considerably improved the results of surgery.
Drainage Tubes
In some cases, a special drainage tube has to be inserted into the eye to drain fluid out. In certain cases the tube works better than a trabeculectomy and can stay in for an indefinite time. A special stitch is inserted in the tube to prevent the pressure from dropping too low. This stitch can be removed after a few months if the pressure stays too high.
Needling
After both trabeculectomy or tube surgery, scar tissue can build up over time which can limit the success of the operations. This scar tissue can be released by loosening some of the scar tissue with a very fine needle (this procedure is called 'needling'). This procedure is combined with an injection of anti-scarring medicine to try and prevent the scar tissue from building up again.
Diode Laser
Sometimes, laser treatment is recommended which may avoid or delay the need for more invasive surgery. The laser produces very small burns in the ciliary body which produces aqueous humour. The reduced production of aqueous humour causes the eye pressure to fall. This treatment may have to be repeated several times.
HOW GOOD WILL THE CHILD'S EYESIGHT BE AFTER TREATMENT?
It is very difficult to give a final prediction of the outcome, especially when the child is very young. Many children have excellent vision into adult life and effectively have normal vision. Children with limited vision can often function well in mainstream school and lead an independent life.
Following treatment, the child will need to attend the clinic at regular intervals and have their condition monitored for life.
GLAUCOMA
What is Glaucoma?
Glaucoma is a group of diseases in which there is progressive damage to the optic nerve (the nerve which transmits light signals from the eye to the brain). The main risk factor for this damage is elevated eye pressure (intraocular pressure), although not all glaucoma is caused by raised pressure. Initially, the disease does not cause any symptoms but if progressive, there is a loss of the peripheral visual field and eventually can lead to blindness if not treated.
What causes pressure within the eye?
Fluid (aqueous humour) is produced inside the eye by a layer of cells known as the ciliary body. The fluid is necessary for the normal functioning of the eye. The fluid drains out of the eye through a structure called the trabecular meshwork. The normal pressure within the eye is between 12 and 21mmHg. If there is an obstruction to the flow of fluid out through the trabecular meshwork, the pressure can rise and glaucoma can develop.
Types of Glaucoma
There are many different types of glaucoma but the two main types are closed angle and open angle glaucoma.
Open angle Glaucoma
Open angle glaucoma is the most frequent type of glaucoma and affects over 2% of adults over the age of 40 years. It becomes more common with increasing age, myopia (short-sightedness) and possibly dibetes. It also is more common and can be more severe in certain ethnic groups, especially blacks. The exact cause of glaucoma is unknown but it does tend to run in families and it is therefore important that relatives are checked by their optometrist on a yearly basis.
Open angle glaucoma is a slow insidious disease which usually affects both eyes. Progressive damage to the optic nerve causes loss of peripheral vision and eventually blindness. The visual loss is gradual and completely painless.
Closed angle Glaucoma
Closed angle glaucoma is less common in the UK. It is more common in elderly patients and those of Oriental race. It is also more frequent in hypermetropes (long-sighted).
Closed angle glaucoma can present very suddenly when the eye becomes very red and painful. This occurs because the trabecular meshwork becomes blocked and the eye pressure rises dramatically. This sudden onset can be preceded by intermittent symptoms such as seeing haloes or rainbows around lights.
This type of glaucoma should be treated as an ocular emergency and often requires laser treatment in hospital. Occasionally, this type of glaucoma can be treated prophylactically (as a preventative measure) if the eyes at risk are identified.
How is Glaucoma Treated?
The vast majority of patients with glaucoma can be treated medically with eye drops. The treatment is to reduce the pressure within the eye and halt the progression of the optic nerve damage. Although glaucoma cannot be cured, treatment can usually control the disease.
If medical treatment fails to control the eye pressure, occasionally laser treatment can be performed, although this is usually only a temporary measure. Glaucoma surgery can be performed in those patients who are not controlled on medical therapy.
Glaucoma Surgery
The most frequent operation for glaucoma is called a trabeculectomy. The aim of this operation is to create a passage for aqueous to drain from the eye into a space beneath the conjunctiva (known as the bleb). It is generally a successful operation but complications may occur, such as excessive drainage causing the pressure to become too low or infection which may be sight-threatening. Excessive scarring beneath the conjunctiva may also cause the operation to fail. Drugs are used frequently nowadays during the operation to prevent scarring (anti-scarring agents).
In very advanced cases or in patients who have certain types of glaucoma, a glaucoma tube can be inserted into the eye to drain away the fluid. This is a major operation with some risk of complications but can offer a useful way of lowering the eye pressure and preventing blindness.
Paediatric Glaucoma