Glaucoma in children is a chronic medical condition with an uncertain prognosis. Sadly, this debilitating disease affects a child’s health-related quality of life over the course of their lifetime. Using case studies, this article puts the spotlight on primary congenital glaucoma, an uncommon but particularly disabling form of the disease.
Childhood glaucoma is intraocular pressure (IOP)-related damage to the eye. This is a heterogeneous group of diseases leading to optic neuropathy and visual field changes, which can be categorised as either primary or secondary. Secondary childhood glaucoma may be either present from birth or acquired. Acquired causes may be related to prior ocular surgery, systemic conditions or ocular trauma. While these categories appear similar to the classification of glaucoma in adults, many of the causes in children are unique to the paediatric population.
there are some unique features to look out for… examination almost always requires general anaesthesia in theatre
The incidence of childhood glaucoma varies among different populations. In developed countries it has been reported to occur in 1:50,000 live births (for all forms of childhood glaucoma). The most common forms are either secondary or acquired. Uncommon childhood glaucoma is associated with a high disease burden for affected patients and their families, and often results in significant visual loss – accounting for up to 5% of blindness in children.
PRIMARY CONGENITAL GLAUCOMA
Primary Congenital Glaucoma (PCG) is a unique and disabling condition. Affected babies can present with a very specific clinical picture. It is essential to recognise the signs and symptoms as early detection and proper treatment by a specially trained ophthalmologist can actually reverse some of the damage, and help delay progression of this sight-threatening disease.
PCG can be difficult to diagnose. It may present either in the neonatal period (birth to one month of age) or in infants between the age of one month and two years. Some children may present late, or have delayed diagnosis, and thus present beyond two years of age.
The typical history and signs of childhood glaucoma can include a combination of the following:
- Large eyes,
- Cloudy eyes,
- Watery eyes,
- Reduced visual responses due to corneal clouding,
- Sensitivity to light, and / or
- Excessive blinking.
Table 1 summarises the diagnostic criteria of PCG, as outlined by the Childhood Glaucoma Research Network (CGRN). Children displaying the symptoms and signs listed here require urgent referral and treatment at a specialist centre with expertise managing this condition. In order to make the diagnosis, almost all children require an examination under anaesthesia. This is performed as soon as possible after presentation with surgical intervention carried out at the same time. Surgery is a critical component of the management of PCG as the disease is due to the fact that the drainage angle has not formed properly and is structurally abnormal.
The initial procedure of choice is angle surgery, either a goniotomy or trabeculotomy, both of which are unique to the management of childhood glaucoma. Glaucoma may be controlled in up to 75% of patients with only one procedure. However, it is important to prepare patients and their parents/care-givers for lifelong follow-up, and possible future surgeries.
Medical therapy is frequently required as a temporising measure prior to surgery, or as adjuvant therapy after partially successful surgical procedures. It is important to realise children may be more vulnerable to adverse effects of medications. They may be unable to verbalise symptoms, and parents may not readily recognise them. Additionally, compliance and adherence issues are greater and more complex in children.
The Childhood Glaucoma Research Network Definition of Childhood Glaucoma
- IOP > 21 mmHg.
- Optic disc cupping (neuroretinal rim narrowing): a progressive increase in cup-disc ratio (diffuse rim narrowing), cup-disc asymmetry of > 0.2 when the optic discs are of similar size, or focal rim narrowing.
- Cornea findings: Haab striae, corneal oedema or diameter > 11mm in newborn, > 12mm in child under one year of age, > 13mm any age.
- Progressive myopia or myopic shift coupled with an increase in ocular dimensions out of keeping with normal growth.
- A reproducible visual field defect that is consistent with glaucomatous optic neuropathy with no observable reason for the visual field defect.
THE CASE OF ELLIOT
Elliot presented when he was two months old (Figure 1). He had been referred in with no visual responses, light sensitivity and absent red reflexes. The photo shows cloudy corneas and globe enlargement bilaterally. Elliot had intraocular pressures of 25mmHg in the right eye and 30mmHg in the left eye.
Figure 2 shows a delightful young Elliot at five months of age after having two surgical procedures (trabeculotomies) in each eye on three separate occasions, all performed under general anaesthesia. His intraocular pressures were 11mmHg on the right and 10mmHg on the left, with recovered vision appropriate for age, and resolution of his corneal oedema. He will need life-long monitoring of intraocular pressures. Additionally, he will need ongoing monitoring of his refraction and vision to ensure normal and equal visual development, and to avoid amblyopia.
THE CASE OF MADELINE
Young Madeline (Figure 3) is a beautiful six month old girl whose parents were concerned about tearing, particularly in the left eye, with associated globe enlargement. After a couple of assessments during which they were falsely reassured, Madeline was finally referred to Westmead Children’s Hospital where she was identified as having left eye PCG. The intraocular pressure (IOP) was 30mmHg and her left eye globe was enlarged. Shortly after this presentation, she had an examination under anaesthesia and successfully underwent her first glaucoma surgery to the left eye.
UNIQUE FEATURES OF PCG
In addition to the signs and symptoms already discussed, there are some unique features to look out for on examination of children with childhood glaucoma and PCG specifically – noting that examination almost always requires general anaesthesia in theatre.
Figure 4 is an intraoperative image of the specific corneal changes referred to as Haab striae. These are horizontal breaks in Descemet’s membrane as a result of accelerated globe enlargement due to raised intraocular pressure. The pliable collagen fibres in a child’s developing eye stretch to compensate for the elevated IOP. This may contribute to corneal clouding, and may result in permanent corneal scarring if treatment is delayed. Figure 5 shows trabeculotomy, the surgical procedure that was performed for these children. A Trabeculotome (pictured) is inserted via a scleral flap into Schlemm’s Canal, and then rotated into the eye, thereby removing the tissue which is obstructing the angle, facilitating aqueous outflow.
Other features unique to glaucoma in children are axial length (AL) enlargement and myopia, which occur because the sclera at this age is vulnerable to the effects of elevated IOP. Rapid changes in refractive status (worsening myopia) and AL enlargement are helpful, both for diagnosing the condition and determining the response to treatment. Continued enlargement of AL beyond the normal range and progressive myopia suggest the glaucoma is inadequately treated. In addition to the vision-threatening effects of optic neuropathy in these children, the other sight-threatening complications to monitor for are AL enlargement, myopia and secondary amblyopia. Figure 6 shows young Razi in his updated glasses correcting his high myopia. Razi has been having occlusion therapy for amblyopia, and at the most recent follow up, had equal vision in each eye – an excellent achievement.
IMPACT ON DEVELOPMENT AND WELLBEING
Childhood glaucoma can have a significant impact on a child’s social development and mental wellbeing from early childhood right through to adolescence and well into adulthood.
Left undiagnosed and untreated, it can lead to visual impairment, which has been shown to have a lifelong impact on all aspects of a child’s development including physically, emotionally, and socially.
Education, future employment opportunities, and social integration remain life-long challenges in children with vision impairment. While it is often a long road ahead for these children, the sooner they are identified and treatment is commenced, the better the management outcomes. In addition to expert medical care, support services for these patients and their families is crucially important.
Dr Tanya Karaconji is a glaucoma specialist and honorary glaucoma consultant at Westmead Children’s Hospital. She is also a clinical senior lecturer at the University of Sydney.
Dr David Wechsler is a glaucoma specialist at Burwood Eye Clinic, and Concord and Macquarie University Hospitals in Sydney. He is also a clinical senior lecturer at the University of Sydney.
- Aponte E, Diehl N, Mohney M (2010). Incidence and Clinical Characteristics of Childhood Glaucoma. Arch Ophthalmol. 128 (4): 478 – 482.
- Weinreb R, Grajewski A, Papadopoulos M et al. (Eds) 2013. Childhood Glaucoma. Kugler Publications Amsterdam.
- Zagora S, Funnell C, Martin F et al (2015). Primary Congenital Glauocma Outcomes: Lessons from 23 yeas of follow-up. Am J Ophth
Managing Children with Childhood Glaucoma: Key Points
- Requires urgent referral to a specialist ophthalmologist – early diagnosis and appropriate treatment can minimise a lifetime of visual impairment.
- Requires examination under general anaesthesia and surgical intervention once diagnosed.
- Drops are only a temporising measure and should only ever be prescribed by an ophthalmologist due to side effects of medications in children.
- Requires monitoring of visual development, treatment of myopia with ametropic correction and amblyopia therapy.
- Visual impairment can be compounded by amblyopia, which leads to lifelong disability.