Pediatric glaucoma: types, tests and treatments

Michael Chaglasian, OD, FAAO, is chief of staff at the Illionois Eye Institute

Stacy Potwin, OD, FAAO, is a staff optometrist at the Veterans Affairs community-based outreach clinic in Charleston, WV

Children are not just miniature adults, and a variety of factors need to be considered when diagnosing and treating pediatric glaucoma patients.

Many of the questions ODs have about adults with glaucoma suspicion are the same for children: Who will go on to develop glaucoma, and why do some children respond well to treatment and others do not?

In many ways, pediatric glaucoma has completely different concerns than adult glaucoma: Children have their whole lives to lose vision from glaucoma, the treatment has numerous years to cause side effects, and many pediatric glaucoma patients will require significantly more surgeries than adults with glaucoma.

Pediatric glaucoma can become aggressive very quickly. Children can lose vision from the glaucoma itself but, unlike adults, can have permanent vision loss from amblyopia and corneal scarring that occur before treatment. Treating an infant, child or adolescent with glaucoma requires a team approach, and optometrists have an important role to play.

Related: Know what common glaucoma mistakes to avoid

Childhood blindness occurs in 0.03 percent of children in high income countries and up to 0.12 percent in undeveloped countries worldwide. Glaucoma accounts for 4.2 to 5 percent of childhood blindness. The main cause of vision impairment in children with glaucoma is amblyopia.¹

Primary congenital glaucoma
Accounting for 50 to 70 percent of childhood glaucoma, primary congenital glaucoma (PCG) is the most common form.

PCG is diagnosed from birth to early childhood (80 percent in the first year of life). There is reduced aqueous outflow through an abnormally developed filtration angle/trabecular meshwork, which begins to form in the fourth gestational month and reaches adult structure by age 8.^1-3 PCG has an autosomal recessive inheritance.⁴ It is bilateral 70 to 75 percent of the time, and can be asymmetric.^1,4

Early diagnosis is imperative because PCG can be aggressive, and children can lose vision quickly. Interestingly, if treatment is successfully performed early enough, glaucomatous cupping can actually be reversed, owing to the immature, elastic lamina cribrosa.^1,2,4,5

Related: Glaucoma facts: Essential perspectives for long-term management

Unlike silent glaucoma in older children or adults, PCG presents as a triad of epiphora, photophobia, and blepharospasm. These symptoms are due to the extremely elevated intraocular pressure (IOP), which causes corneal clouding and buphthalmos at the corneoscleral junction, eventually overburdening the endothelium and leading to Haab striae of Descemet’s membrane. This, in turn, can lead to permanent corneal scarring and vision loss.^1,3,5,6

As opposed to adults with glaucoma, whose outflow system becomes faulty over many years of use, children born with faulty drainage systems that cause PCG require surgery as first-line treatment, usually goniotomy or trabeculotomy if the cornea is clear.² If the cornea is not clear, or if the angle surgeries do not control the IOP, the next step is trabeculectomy or aqueous shunt devices (e.g., Molteno, Ahmed, Baerveldt implants).¹

Related: Coats’ disease: A case study of a 4-year old boy

Minimally invasive glaucoma surgery (MIGS) shows emerging potential for reduced trauma to the conjunctiva, preserving this area in a population who may need multiples surgeries, but further investigation is needed.^7,8

Cyclodestruction is the last resort for a blind, painful eye that is refractory to other treatments.^1,4,9

Medications are used for PCG as a secondary option. For infants and young children, they can be used to lower IOP and reduce pain and photophobia prior to surgery or in those with only partially successful surgical outcomes.^1,4,9 A total of 70 to 90 of true PCG patients who undergo 1 to 2 procedures after 3 months of age but before 2 years of age are cured of the condition without further surgical or medical intervention.^3,6,9

The success rate is lower for those who receive surgery from birth to 2 months of age, most likely due to the more severe filtration anomaly and thus immediate diagnosis and treatment.⁴

Children with PCG are at a lifelong risk of retinal detachment and increased risk of age-related cataract surgery complications.²

Related: Look at more than the optic nerve head in glaucoma patients

Secondary to cataract removal
The second most common form of childhood glaucoma is secondary to congenital cataract removal.

This type of glaucoma is usually open angle and can occur immediately or years after surgery. Anyone who has had congenital cataract surgery is a lifelong glaucoma suspect. The risk of developing glaucoma is 17 percent at 5 years post-surgery and is similar for those receiving initial intraocular implant and those initially left aphakic.^1,10

Early cataract surgery is associated with improved visual outcomes but increased risk of glaucoma development. This secondary type of childhood glaucoma is treated first with medications.^1,10

Read: ODs: Redefine your role in glaucoma collaborative care

Juvenile open-angle glaucoma
The final type of childhood glaucoma is another primary glaucoma, juvenile open-angle glaucoma (JOAG), which is considered to be diagnosed from age 4 to age 35 and accounts for 0.2 percent of glaucomas. This disease has autosomal dominant inheritance and affects 1 in 50,000 people.

JOAG is often more severe than POAG and can be markedly asymmetric. Risk factors for JOAG include ocular hypertension (often above 40 mm Hg), being male, myopia (can be significant and progressive from axial elongation), and family history of glaucoma. Patients often present with irreversible optic disc cupping and visual field defects.^1,4,5,11-13

Puberty can make treating JOAG more challenging, with rapid growth and development along with hormonal changes causing IOP to change during this time (usually lowering during puberty, then increasing after).²

Secondary causes of glaucoma (pigment, steroid, inflammation, trauma) should be ruled out before diagnosing JOAG. Often, the diagnosis is made incidentally, but patients can present with a headache, which can be unilateral and severe. The first line of treatment for JOAG is medication. Due to their elevated IOP, these patients require laser or surgical interventions more often than POAG patients.¹²

Read: Deciding between glaucoma or physiologic cupping

Treatment
Medications used to treat childhood glaucoma are similar to those used for adults, with some differences. Brimonidine (Alphagan P, Allergan), which crosses the blood–brain barrier, is absolutely contraindicated in infants and young children due to central nervous system toxicity. It should even be used in caution in older children and has been shown to not have a significant effect on IOP reduction.^1,4-6,9

Beta blockers are often first-line treatment and show a 20 to 30 percent reduction in IOP, but are best used at the lowest dose possible and gel formulation; selective betaxolol (Betopic-S, Alcon) should be considered in children with asthma or other breathing conditions. Topical carbonic anhydrase inhibitors (CAIs) are safer (contraindicated if clear corneal transplant) but not as effective as oral CAIs (contraindicated in infants due to risk of metabolic acidosis) and are usually reserved for short-term use to help clear the cornea prior to angle surgery in PCG.^1,4,5,9

Finally, prostaglandin analogs (PGAs), considered first-line treatment in adults, are also well tolerated in children, but not as effective. The greatest effect is seen in older children who have been diagnosed with JOAG, who use it as monotherapy.^1,4,5,9,14

Read: How inflammation may play a role in retinal disease

Children and steroids
Let’s talk more about steroid responders and steroid-induced glaucoma in children. In total, 20 percent or more of children treated with steroids have been shown to develop glaucoma, and this glaucoma can be more severe with an earlier onset and more rapid progression as compared to adults. Additionally, the steroid response may not be reversible, and the patient can be asymptomatic.

Steroids cause increased IOP by increasing the resistance within outflow pathways. Many ocular conditions in childhood are treated with topical steroids, including uveitis, blepharoconjunctivitis, and vernal keratoconjunctivitis.

Topical steroids are the most common cause of steroid response or glaucoma in children. Topical steroids with the lowest effect on IOP are fluorometholone (FML, Allergan), loteprednol (Lotemax, Alrex; Bausch + Lomb), rimexolone (Vexol, Alcon), and medrysone (HMS, Allergan). An alternative option is topical cyclosporine (Restasis, Allergan; Cequa, Sun Pharma), which has been shown to be effective at treating ocular surface inflammation in children.¹⁵

Read: Misdiagnosis when clinical findings don’t make sense

Examining infants and children
Optometrists are primary ocular health providers and have a responsibility to be aware of these conditions, know what to look for in each age group and population, and when to refer. ODs who are InfantSEE providers may be the first to be aware of changes indicative of PCG, such as large-looking eyes, possibly signifying an abnormally large horizontal corneal diameter.

Abnormal corneal diameters (>11 mm in an infant, >12 mm in a child less than 1 year of age, or >13 mm in any age) are suggestive of glaucoma.

Other signs to be aware of include a cloudy, tearing eye with corneal scarring in a baby who avoids opening her eyes, especially with bright lights. ODs may get the referral from the pediatrician to delineate nasolacrimal duct obstruction or conjunctivitis from PCG.^4,6

Start a pediatric exam by first noticing visual behaviors and the appearance of the face and eyes, noting nystagmus or strabismus. ODs may see a child for a pre-kindergarten eye exam and notice that, even with cyclopledgic refraction, the child is myopic. Knowing that children should still be hyperopic at that age (any myopic child should be a glaucoma suspect), make sure that IOP is checked and closely evaluate the cornea, iris, and anterior segment after taking a detailed case history.^1,6

For infants and young children especially, Icare tonometry will likely be the easiest way to obtain IOP, although it is known to have slightly higher readings than other techniques.10 Tono-Pen (Reichert) is another good option, but it requires numbing. IOP will be higher in a crying, lid-squeezing, breath-holding, or fighting child.^2,6,11

Amblyopia is the most common cause of visual impairment in children with glaucoma, and the brain can suppress an eye very quickly at a young age; IOP cannot be the only element treated in childhood glaucoma. Optometrists will also diagnose potential for or already present amblyopia, and treat it with appropriate glasses, patching, and vision therapy.² ODs can readily diagnose, treat, and manage amblyopia, high refractive error, and necessary contact lens fittings for these patients.

Other beneficial testing includes stereoscopic fundus photos (document abnormalities that can mimic glaucoma such as optic disc pits, tiled discs, optic nerve hypoplasia), visual field testing (not useful until at least age 6, preferably age 8 years or older). A handheld slit lamp would also be helpful for evaluating children not old enough to sit in the slit lamp.^5,11,16

The pachymetry of children who had congenital cataracts removed or with aniridia will be thicker, but they develop glaucomatous damage much faster than other children, and patients with PCG and JOAG have thinner than average corneal thickness.^1,11,16

Scanning of the optic nerve can be helpful as well, although there is no normative database for ages less than 18 years. Confirmation of larger than average discs (and therefore larger cups) can be documented, and changes over time can be monitored when comparing back to baseline.

Ocular coherence tomography (OCT) has confirmed that the ISNT rule (inferior ≥ superior ≥ nasal ≥ temporal) applies in children.¹¹

Related: Unconventional clinical options for lowering IOP

Clinical pearls
Evaluate the parents of childhood glaucoma suspects to determine if there is a family history of glaucoma or hereditary large optic nerves.¹¹

If an OD is suspicious of glaucoma in a child, consider obtaining a modified diurnal curve of IOP. In children without glaucoma, the IOP will vary only 1 to 2 mm Hg between eyes and over time, but in glaucoma IOP can vary 10 mm Hg or more over time and 3 mm Hg or more between eyes.⁵

When following a child with ocular hypertension (OHTN) and no evidence of glaucoma, keep in mind that one study showed that 25.6 percent of children who had two or more episodes of elevated IOP (on different days) went on to convert to glaucoma.¹⁷

The decision to treat OHTN to decrease risk of conversion to JOAG should be based on the likelihood of visual impairment (pediatrics have many more years to lose vision), cost (many more years to pay for treatment), side effects of treatment (decades to produce side effects and/or failure) and quality of life, which can be affected by a complicated dosing schedule.^5,12

Medications have increased side effects in children because children’s enzyme-metabolizing systems are not yet fully developed.³ Consider preservative-free glaucoma drops for children who will be on prolonged topical glaucoma treatment.¹⁸ Also, recommend punctual occlusion and remind parents/caregivers to pay close attention to adverse side effects in this population, who may not be able to verbalize them.¹

The Childhood Glaucoma Research Network (CGRN) can be a resource for anyone who sees pediatric patients. There is information available for parents and caregivers of children with glaucoma, including a visual impairment toolkit and a link to connect with others.^2,6

Optometrists should not hesitate to seek the support of a pediatric glaucoma specialist, pediatric ophthalmologist, or adult glaucoma specialist for surgical consultation, especially in infants. ODs must remember that children are not just miniature adults and have different clinical considerations as patients.

Related: Be leery of large optic cups when screening for pediatric glaucoma

References:

1. Marchini G, Toscani M, Chemello F. Pediatric glaucoma: current perspectives. Pediatric Health Med Ther. 2014;5:15-27.
2. Karmel M. Childhood glaucoma. EyeNet Magazine. Available at: https://www.aao.org/eyenet/article/childhood-glaucoma?august-2016. Accessed 5/20/20.
3. Karmel M. Caring for children with congenital glaucoma. EyeNet Magazine. Available at: https://www.aao.org/eyenet/article/caring-children-with-congenital-glaucoma?may-2006. Accessed 5/20/20.
4. Freedman S. Managing pediatric patients with glaucoma. Review Ophthal. 2016 May 10;23(5):80-84.
5. Freedman SF. Pediatric glaucoma. Glaucoma Today. 2006 Jul/Aug:25-28.
6. Ho CL, Walton DS. Primary congenital glaucoma: 2004 update. J Pediatr Ophthalmol Strabismus. 2004 Sep-Oct;41(5):271-288.
7. Do A, Panarelli JF. Pediatric MIGS. Glaucoma Today. 2017 Mar/Apr:48-49.
8. Chang TCP. MIGS in kids. Glaucoma Today. 2016 Sept/Oct:54-56.
9. Huang W. Pediatric glaucoma: A review of the basics. Rev Ophthalmol. 2014 April;21(4):76-80.
10. Giangiacomo A, Beck A. Pediatric glaucoma: review of recent literature. Curr Opin Ophthal. 2017 Mar;28(2):199-203.
11. Beck A. Evaluating and managing optic disc cupping in children. Glaucoma Today. 2009 Jan/Feb:26-28.
12. Bar-Sela SM, Feldman RM. Diagnosing and managing ocular hypertension in teenagers. Glaucoma Today. 2009 Jan/Feb:29-32.
13. Chak G, Mosaed S, Minckler DS. Diagnosing and managing juvenile open-angle glaucoma. EyeNet Magazine. Available at: https://www.aao.org/eyenet/article/diagnosing-managing-juvenile-openangle-glaucoma-2?march-2014. Accessed 5/20/20.
14. Black AC, Jones S, Yanovitch TL, Enyedi LB, Stinnett SS, Freedman SF. Latanoprost in pediatric glaucoma--pediatric exposure over a decade. J AAPOS. 2009 Dec;13(6):558-562.
15. Nuyen B, Weinreb RN, Robbins SL. Steroid-induced glaucoma in the pediatric population. J AAPOS. 2017 Feb;21(1):1-6.
16. Stuart A. The challenge of diagnosing pediatric glaucoma. EyeNet Magazine. 2009 Nov/Dec. Available at: https://www.aao.org/eyenet/article/challenge-of-diagnosing-pediatric-glaucoma?novemberdecember-2009. Accessed 5/20/20.
17. Greenberg MB, Osigian CJ, Cavuoto KM, Chang TC. Clinical management of outcomes of childhood glaucoma suspects. PLoS ONE. 2017 Sep;12(9):e0185546.
18. Walton DS. Managing the pediatric glaucomas. Glaucoma Today. 2009 Jan/Feb:21-24.