Pediatric glaucoma encompasses a diverse range of conditions. While these patients will need to establish a relationship with a pediatric ophthalmologist due to the high likelihood of surgery, we as optometrists also serve an important role in referring these patients, monitoring them in between visits with their ophthalmologist, and providing them with other vision services outside of their glaucoma diagnosis.
By doing so, we can ensure that these patients are well taken care of and have the best visual prognosis.
Overview of pediatric glaucoma
To diagnose a patient with pediatric glaucoma, according to the Childhood Glaucoma Research Network (CGRN), two or more of the following must be present; if only one is present, a patient can be considered a glaucoma suspect:1
- Intraocular pressure (IOP) greater than 21mmHg.
- Cup-to-disc asymmetry of 0.2 or more.
- Focal thinning of the optic nerve rim.
- Corneal changes (ex., Haab striae, edema, or enlargement).
- Myopic shift or increasing axial length.
- Reproducible visual field defect.
Classifying pediatric glaucoma
The CGRN has divided pediatric glaucoma into seven subsets:
Primary congenital glaucoma (PCG)
While “congenital” implies that the patient is born with PCG, the condition can present at any point in the first year of life. Only 25% of patients with PCG have the condition present at birth.2
The classic triad of symptoms for PCG is photophobia, epiphora, and blepharospasm; other symptoms include corneal enlargement, Haab striae, corneal edema and/or opacification, and buphthalmos.2
Juvenile open-angle glaucoma (JOAG)
Patients with juvenile open-angle glaucoma are characterized by an autosomal dominant inheritance pattern and an age of onset between 3 and 40 years.
Compared to POAG, it is more rapidly progressive with more significantly elevated IOP measurements.3
Glaucoma following cataract surgery (GFCS)
Pediatric cataract surgery can result in glaucoma whether or not an intraocular lens (IOL) is placed. It can manifest anytime from days to years after cataract surgery.
One risk factor is an earlier age at the time of cataract surgery; however, earlier surgical intervention reduces visual deprivation and the risk of amblyopia.4
Glaucoma associated with non-acquired systemic disease or syndrome
Non-acquired systemic conditions that can cause pediatric glaucoma include Sturge-Weber syndrome, neurofibromatosis type 1, Marfan syndrome, and Stickler syndrome.5
Glaucoma associated with non-acquired ocular anomalies
Non-acquired ocular anomalies that can result in pediatric glaucoma include aniridia, Axenfeld-Rieger anomaly, Peters anomaly, and persistent fetal vasculature, among others.6
Glaucoma associated with acquired conditions
Acquired conditions that can lead to childhood glaucoma include retinopathy of prematurity (ROP), ocular tumors, trauma, hyphema, traumatic iritis, lens subluxation/dislocation, and ocular surgery.7
Glaucoma suspect
For patients who present with only one of the above diagnostic criteria, close monitoring is still required to determine if and/or when they may convert to glaucoma.1
Prevalence of pediatric glaucoma
Pediatric glaucoma affects more than 300,000 children in the world and accounts for 5% of blindness in the pediatric population.1 The prevalence of each subtype varies depending on the population being studied. For example, a retrospective study in Egypt found that PCG was the most commonly diagnosed form, while one done in Boston found that GFCS was the most common.1
PCG is estimated to occur in about 1 in 10,000 births and is the most common primary pediatric glaucoma.8 The likelihood of secondary glaucoma varies depending on the etiology of the initial condition. Aniridia occurs in 1.8 in 100,000 births; approximately 50% of these patients will go on to develop glaucoma.6
Similarly, around 50% of patients with Sturge-Weber syndrome are likely to be diagnosed with glaucoma, although some estimate the incidence to be closer to 70%.5 JOAG is estimated to occur in between 0.38 to 2 of 100,000 individuals between the ages of 4 and 20 years.3
Recent research on pediatric glaucoma
There are a myriad of current research topics in the world of pediatric glaucoma. Optimizing surgical outcomes is a top concern; consequently, the efficacy of different surgical techniques, such as the recent PAUL glaucoma implant vs. traditional Ahmed or Baerveldt shunts, are being reviewed to determine best practices.9
Other research avenues include what factors are most likely to make pediatric cataract patients develop glaucoma after lensectomy, which glaucoma suspects are at the highest risk of conversion, and what socioeconomic factors have the highest impact on outcomes in childhood glaucoma patients.10,11,12
The OD’s role in the diagnosis of pediatric glaucoma
As primary care providers, optometrists are often the first eyecare providers examining pediatric patients, especially through the American Optometric Association's (AOA’s) InfantSEE program.
As such, it is important that we are able to recognize the signs and symptoms of pediatric glaucoma. Our evaluation is likely to vary depending on the patient’s age, but it is important to do as much as we can to determine the patient’s visual status.
Some of the diagnostic testing that can be done to help determine a patient’s risk of glaucoma include:
- Corneal Diameter: Measuring corneal diameter is critical in patients with suspected primary congenital glaucoma.
- Any diameter above 12.0mm before 1 year of age indicates an abnormality, especially in cases of asymmetry between the two eyes.8
- Tonometry: While Goldmann tonometry is the gold standard, iCare or Tono-Pen measurements are often easier to obtain on young patients and can also provide vital information.
- Visual Field Testing: Humphrey visual field testing should be completed as soon as a child is capable of maintaining their focus and completing the test in order to quantify possible field loss.13
- Pachymetry: Corneal thickness should be measured in all glaucoma suspects and glaucoma patients to determine if IOP adjustment is necessary.14
- Refraction and Axial Length Measurements: Cycloplegic retinoscopy should be done to identify myopia, astigmatism, and/or any corneal irregularities associated with pediatric glaucoma.
- A-scan ultrasonography also provides information on the possible elongation of the eyeball associated with primary congenital glaucoma.8
- Optic Nerve Evaluation: Evaluation of both optic nerves with either direct or indirect ophthalmoscopy is essential in order to evaluate for damage and/or asymmetry.
- Fundus photography is helpful in determining progression over time.
- Optical Coherence Tomography (OCT): OCT testing can provide valuable information about optic disc size and damage over time.
- OCT of both the optic nerve and macula should be done once the patient can focus long enough for the test; the anterior chamber angle can also be imaged.
- One important note is that the normative database incorporated into the OCT is for patients 18 and older, so it is not as applicable to pediatric patients.14
Treatment options for optometrists to manage pediatric glaucoma
Most pediatric glaucoma patients will eventually require surgical intervention; however, optometrists can play an important role in medical treatment prior to and as an adjunct to surgery.
The lowest possible dosage of medication should be used for any pediatric glaucoma patient due to their still-developing systems. For patients who will be on long-term medications, preservative-free formulations can be considered.14
Beta-blockers are typically considered the first line of treatment for pediatric glaucoma patients, but they are contraindicated in patients with bronchospasm and cardiac arrhythmias. Carbonic anhydrase inhibitors (CAIs) are second line but should be avoided in patients with sulfa allergies and any corneal compromise.8
Because it can cross the blood-brain barrier, brimonidine use in children can result in extreme fatigue and is generally avoided. Prostaglandin analogs, while efficacious, are generally avoided due to increased iris pigmentation and lash growth. However, they can be first line for JOAG, as long as the patient and parent are aware of the possible side effects.8
Guidelines and protocol for referral of pediatric glaucoma
Prompt diagnosis and referral are critical for pediatric glaucoma patients, especially in PCG patients where earlier surgical intervention usually results in better visual outcomes. For older patients and those for whom medical intervention is the first line of treatment, it is important to be aware of the legal guidelines for your jurisdiction regarding treatment of pediatric glaucoma.
For example, in Virginia, state law states that optometrists may treat glaucoma “excluding the treatment of congenital and infantile glaucoma.”15 The California Business and Professions Code gives optometrists the authority to administer “medical treatment of all primary open-angle, exfoliation, pigmentary, and steroid-induced glaucomas in persons 18 years of age or over.”16
Co-management with a pediatric ophthalmologist allows optometrists to continue to provide care for pediatric glaucoma patients while staying within our scope of practice. Seeing patients for regular IOP checks and other diagnostic testing in the optometric setting can help free ophthalmologists to focus on more surgical patients; it can also be less of a travel burden for patients.
Co-managing pediatric glaucoma: Counseling and long-term follow-up
The prognosis for pediatric glaucoma varies based on the type of glaucoma and the initial visual status of the patient upon diagnosis; in some cases, it may be necessary to refer patients for low vision services as part of their counseling.
When co-managing a pediatric glaucoma patient, it is crucial to make sure that the parents and, if they are old enough, the patient, understand how important compliance is, both in terms of medications and keeping up with their follow-up appointments.
Parents of PCG patients should be advised that surgical intervention is highly likely as it is considered the mainstay of treatment, and it is possible that multiple surgeries will be needed. Just like any pediatric patient, pediatric glaucoma patients will require regular comprehensive eye exams.
Pediatric glaucoma patients are highly likely to require optical correction due to a number of possible factors (ex., myopia due to increased axial length, pseudophakia requiring an ADD at near, etc.), and we as optometrists are more than capable of managing the refractive needs of these patients. Refractive amblyopia due to high astigmatism (a side effect of corneal stretching) can also be managed by the optometrist.14
Conclusion
Pediatric glaucoma, while a rare condition, can be visually devastating if it is improperly managed. Establishing a relationship with local pediatric ophthalmologists is essential to give patients the best visual prognosis both at the time of diagnosis and beyond.
Remember, these patients are not just their glaucoma—they will need lifelong comprehensive eyecare, which optometrists are in a prime position to provide.
