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Glaucoma

  • Glaucoma in Infants

    Glaucoma rarely affects infants. It is estimated that 1 in 5,000 to 10,000 children under 2 years of age will develop glaucoma. Glaucoma in children under 2 years of age is called infantile (or congenital) glaucoma. Prompt recognition and timely treatment will improve the chance of a good outcome. Infantile glaucoma is the result of failure of fluid to escape from the anterior chamber of the eye resulting in increased pressure within the eye. The young eye responds to this increased pressure differently to an adult eye.

    How would a parent know if a child is suffering from glaucoma?


    In keeping with the rest of an infant the immature eye is floppy and somewhat elastic. Thus early in life (that is before the second birthday) raised intraocular pressure will stretch the eye and actually cause it to increase in size (it expands in all directions/ rather like a balloon being inflated). Early medical writers termed this buphthalmos (=ox eye) as this increase in size of the eye was thought to make the infant's eye look like an ox's eye.

    The stretching of the eye has a number of harmful effects on the eye. As the eye enlarges the cornea increases in size. One of the many layers of the cornea, Descemet's membrane, does not have much give and rather than stretch it will split as the eye enlarges. This splitting results in the cornea losing some of its clarity and becoming cloudy. This cloudiness of the cornea is the result of fluid entering the cornea from the anterior chamber via the splits in Descemet's membrane and is known as corneal oedema. Corneal oedema causes discomfort and sensitivity to light and increased tear production.

    Thus the cardinal features of infantile glaucoma that may be identified by a parent are photophobia (sensitivity to light), increased tearing with an enlarged and cloudy cornea.

    What happens when glaucoma is suspected in a young child?


    The child needs to be assessed by an ophthalmologist. Ideally the child should be referred to an ophthalmologist with experience in managing childhood glaucoma. Often an examination under anaesthetic is required to adequately examine the child and confirm the diagnosis of glaucoma. The diagnosis is confirmed by the presence of typical corneal changes (enlargement, clouding and splits in Descemet's membrane), raised intraocular pressure and optic disc cupping.

    What treatment will be needed?


    Initial treatment may be eye drops or medication by mouth to lower the pressure in the eye. Over the long-term medications have a significant risk of complication in young children and compliance with medical therapy is an even greater problem with young patients than it is with older ones. Surgery is usually required and has a very high success rate.

    Infantile glaucoma is the result of blockage of aqueous (fluid) drainage at the trabecular meshwork of the anterior chamber angle. Operations aim to restore the more normal drainage of aqueous. The two most common operations are goniotomy and trabeculotomy. Both involve opening up the tissue in the angle to enable the aqueous to escape more easily from the eye and thus lower the pressure. All surgery for infantile glaucoma is done under a general anaesthetic. It is not uncommon for more than one operation to be needed to completely control the raised pressure of infantile glaucoma.

    In some instances operations more often used with adult glaucoma such as trabeculectomy or Molteno tubes are used. These procedures aim to create a controlled leak or "fistula" by which the aqueous can bypass the trabecular meshwork and escape from the eye. As with adults anti-inflammatory and antibiotic drops are used post operatively. When trabeculectomy is performed in children an antimetabolite such as 5-fluorouacil (5-FU for short) is very often used as children heal much more rapidly than adults.

    Will there be any pain?

    Before treatment is started there may be some pain related to the corneal oedema and the photophobia. Pain after surgery for infantile glaucoma is usually mild and easily controlled with paracetamol. Severe pain may indicate a significant problem such a post-operative infection.

    Will there be a long stay in hospital?


    Most glaucoma surgery in infants can be done safely as a day case without the need for overnight admission. If surgery is required within the first four to five weeks of life the infant may remain in overnight for monitoring after the anaesthetic.

    What follow up will be required?


    Regular and life long follow up will be required. When the child is quite young it may be necessary for periodic examinations under anaesthetic. As well as monitoring for raised intraocular pressure the follow up will involve monitoring of the development of vision, determine the need for glasses and when older assess any damage to peripheral visual field.

    Will my child's vision be impaired?


    Severe loss of vision due to infantile glaucoma is fortunately rare. It is particularly seen if the onset of the glaucoma is at or before birth. Glasses are commonly required for myopia (short sightedness). This is due to the overall length of the eyeball being increased by the raised intraocular pressure. Photophobia may be a persistent problem if the splits in Descemet's membrane are severe.

    What causes infantile glaucoma?

                                                                                                                                                                                                                                                   The precise cause of primary congenital glaucoma (PCG) is not known.  In Australia approximately 20% of children with PCG have a mutation in the CYP1B1 gene.  If one child in a family has PCG then the risk for a subsequent child to be affected is ~5% and if there are two affected children in one family the risk for subsequent children is 25%.  Australian data suggests that the risk for a parent with a diagnosis of PCG of having an affected child is 2%.  

    Infantile and childhood glaucoma may be associated with other abnormalities in the eye.  The most common of these is a history of having had cataract surgery as an infant, this is called “aphakic glaucoma”.  Other eye abnormalities that can be associated with glaucoma are the anterior segment dysgenesis group of disorders which includes Rieger syndrome.  Glaucoma can occur in association with other systemic abnormalities such as the Sturge-Weber syndrome and rubella (German measles)  embryopathy.  Juvenile arthritis may cause inflammation in the eye (uveitis) that may be complicated by the development of glaucoma.

    What are the chances of another baby of mine developing glaucoma?


    The risk is not zero but it is quite low.

    Will my child's lifestyle need to alter in any way?


    Most children with infantile glaucoma lead normal lives. Glasses may be required for focusing errors or photophobia. The small number of children with more severe visual impairment will require some degree of help at school.

    What research is being done into the causes and treatment of infantile glaucoma?


    Most research into the causes and treatment of glaucoma is directed to understanding adult glaucoma. Fortunately many of these advances can be modified to treat children with glaucoma.