Neurofibromatosis 1 (NF1), also known as von Recklinghausen disease or peripheral neurofibromatosis, is the most common type, with a prevalence of 1 in 3000–5000 persons. NF1 is localized to band 11 of the long arm of chromosome 17 and is inherited in an autosomal dominant fashion in approximately 50% of cases, with the other cases being sporadic. Ectropion uveae is a common ocular finding whose presence in a neonate should prompt a workup for NF. Other ocular findings include Lisch nodules, optic nerve gliomas, eyelid neurofibromas, and glaucoma. Systemic findings include cutaneous café-au-lait spots, cutaneous neurofibromas, and axillary or inguinal freckling.
Neurofibromatosis 2, or central neurofibromatosis, is defined by the presence of bilateral acoustic neuromas and is not associated with glaucoma.
Secondary Glaucomas
Many of the causes of secondary glaucoma in infants and children are similar to those in adults (see Table 6-2). Trauma, inflammation, steroid use, and topiramate-induced angle closure are frequent causes of secondary glaucoma in all age groups. Lens-associated disorders causing angle-closure glaucoma include Marfan syndrome, homocystinuria, Weill-Marchesani syndrome, and microspherophakia. Posterior segment disorders such as persistent fetal vasculature (PFV); retinopathy of prematurity (ROP); and familial exudative vitreoretinopathy (FEVR); as well as tumors of the retina, iris, or ciliary body can also result in glaucoma. Retinoblastoma, juvenile xanthogranuloma, and medulloepithelioma are some of the intraocular tumors known to lead to secondary glaucoma in infants and children. Rubella and congenital cataract are important conditions that are also associated with secondary pediatric glaucoma.
Aphakic Glaucoma
Of children who undergo surgery for congenital cataract, 15%–50% or more develop glaucoma. Although most aphakic glaucoma develops within 3 years of cataract surgery, the patient is at risk of developing glaucoma for his or her entire life and therefore requires lifelong follow-up. Risk factors for the development of aphakic glaucoma include cataract surgery in the first year of life, postoperative complications, and small corneal diameter. While the underlying mechanism is unclear, it appears that congenital anomalies, surgically induced inflammation, and altered intraocular anatomy postoperatively may play a role. Removal of all residual cortex during cataract surgery may reduce the occurrence of pediatric aphakic glaucoma.
Aponte EP, Diehl N, Mohney BG. Incidence and clinical characteristics of childhood glaucoma: a population-based study. Arch Ophthalmol. 2010;128(4):478–482.
Beck AD. Diagnosis and management of pediatric glaucoma. Ophthalmol Clin North Am. 2001;14(3):501–512.
Chen TC, Bhatia LS, Halpern EF, Walton DS. Risk factors for the development of aphakic glaucoma after congenital cataract surgery. J Pediatr Ophthalmol Strabismus. 2006;43(5):274–280.
Papadopoulos M, Cable N, Rahi J, Khaw PT; BIG Eye Study Investigators. The British Infantile and Childhood Glaucoma (BIG) Eye Study. Invest Ophthalmol Vis Sci. 2007;48(9):4100–4106.
Tai TY, Mills MD, Beck AD, et al. Central corneal thickness and corneal diameter in patients with childhood glaucoma. J Glaucoma. 2006;15(6):524–528.
Yanovitch TL, Freedman SF. Pediatric glaucoma. Focal Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 2012, module 3.
Evaluating the Pediatric Glaucoma Patient
Evaluating the pediatric glaucoma patient is very different from evaluating the adult patient with
glaucoma. Ophthalmologists should be prepared with an orderly system for evaluating infants and young children in both the office and the operating room when required. All equipment needed for the examination should be readily available. For examinations under anesthesia (EUAs), the ophthalmologist should have a prepared checklist and dedicated storage that houses all supplies needed for the examination (Table 6-5). Efficiency in performing measurements and recording data in the operating room can minimize the time that the patient is under anesthesia.
Table 6-5
History
The ophthalmologist should ask questions that will elicit information about the patient’s signs and symptoms. When evaluating an infant, the ophthalmologist should ask the caregiver whether the baby is fussy or irritable, whether the child is not feeding well or is losing weight, and whether the baby cries when taken outside, into the sunshine. The caregiver’s observations regarding corneal clouding should be sought, specifically as to whether the clouding is intermittent or constant.
For evaluation of school-aged children, the history should include any failed vision screenings, any change in academic performance, and complaints about trouble seeing the blackboard. It is helpful to know which extracurricular activities the child is involved in. A complete history should include the names of previous physicians who have been consulted; all prior ocular and systemic medical and surgical treatments; family history of congenital glaucoma and other ocular and systemic disorders; medication use (with particular attention to all forms of steroids); and allergies.
Visual Acuity
Testing of visual acuity in infants and young children is discussed in BCSC Section 6, Pediatric Ophthalmology and Strabismus. Refraction should be performed and may identify myopia from axial enlargement, and/or astigmatism from corneal irregularity. Decreased vision may result from endstage glaucomatous optic nerve damage, amblyopia, corneal scarring, or other associated ocular disorders (retinal detachment, macular edema, cataract, lens dislocation).
External Examination
The ophthalmologist should look for buphthalmos and other signs and symptoms of PCG, including epiphora and blepharospasm (see Fig 6-1). The examination should be directed at features of primary and secondary glaucomas other than PCG, including chromosomal abnormalities, phakomatoses, connective tissue disorders, and Axenfeld-Rieger syndrome.
Anterior Segment Examination
As discussed previously, corneal enlargement and opacification are important signs of the onset of
glaucoma in patients younger than 3 years. Corneal diameter should be measured with calipers or a ruler. The normal corneal diameter is approximately 10–10.5 mm in full-term newborns, increasing to 11–12 mm by age 1. Eyes with congenital glaucoma may have a corneal diameter greater than 12 mm in the first year of life. Corneal edema may be due to elevated IOP or Haab striae and may range from mild haze to dense opacification of the corneal stroma (see Fig 6-1). Retroillumination after pupillary dilation may help visualize Haab striae. Evaluation for other anterior segment anomalies, such as aniridia, iridocorneal adhesions, and corectopia, may provide insight into the underlying diagnosis.
Tonometry
Accurate tonometry is vital in the assessment of the childhood glaucomas. IOP may be falsely elevated in the uncooperative or struggling child. Often, the clinician can successfully measure the IOP of an infant younger than 6 months without general anesthesia or sedation by performing the measurement while the infant is feeding or immediately thereafter. For this group of patients, the Tono-Pen (Reichert Ophthalmic Instruments, Depew, NY) or pneumotonometer works best for inoffice tonometry. The Perkins tonometer can also be helpful for children who are too young to cooperate for Goldmann tonometry at the slit lamp. The rebound tonometer is a newer instrument that does not require topical anesthesia and that has been shown to decrease the number of EUAs required in the management of pediatric glaucoma. Initial reports indicate that measurements in patients with congenital glaucoma were higher with rebound tonometry than with the Perkins tonometer.
Anesthesia is usually required for accurate IOP assessment of older infants (>6 months) and young children. However, most general anesthetic agents and sedatives can profoundly lower IOP. Exceptions include chloral hydrate, which does not affect IOP, and ketamine, which may raise IOP. In addition, in preparation for general anesthesia, infants may become dehydrated, which can also reduce IOP. Increased IOP during general anesthesia may result from endotracheal intubation, upward drift of the eyes, or possible induced laryngospasm. It is best to coordinate with the anesthesiologist before the child is brought to the operating room and arrange to take the IOP measurement immediately after induction of general anesthesia (preferably before intubation), which should ensure that the anesthesia has not yet maximally lowered the IOP.
The normal IOP in newborns is in the low teens, increasing to adult levels of 10–20 mm Hg by middle childhood. Glaucoma should be suspected if IOPs are elevated or asymmetric in a cooperative or anesthetized child.
Martinez-de-la-Casa JM, Garcia-Feijoo J, Saenz-Frances F, applanation tonometer in congenital glaucoma. J Glaucoma.
et al. Comparison of rebound tonometer and Goldmann handheld 2009;18(1):49–52.
Central Corneal Thickness
The role of pachymetry in the diagnosis and management of pediatric glaucoma is unclear. The average central corneal thickness (CCT) is 540–560 µm in children without glaucoma. CCT is lower than average in eyes with congenital glaucoma and in children with Down syndrome; CCT is higher than average in eyes with aphakic glaucoma and aniridia. The effect of CCT on the accuracy of IOP measurements in these groups is unclear, and nomograms cannot accurately be used to “correct” IOP measurements for differences in CCT measurements.
Gonioscopy
Gonioscopy provides important information about the mechanism of the pediatric glaucoma as well as evidence of prior surgeries. An EUA is usually required for gonioscopic examination of younger