Richard W. Hertle, MD, FAAO, FACS, FAAP
In the more than 25 years that I have been caring for infants, children, and families of patients with glaucoma, I have learned that this is one of the most devastating groups of eye diseases. It not only severely affects the developing visual system but also forever changes the lives of the patient’s family. Repeated visits to the physician, hospital, operating room, and social support systems, as well as the frequent need for medication administration, results in significant stress to the families. If a physician decides to assist with the care of these patients, an understanding of the chronicity, complexity, and unique social challenges of this group of patients is needed.
Glaucoma in infancy and childhood constitutes a rare but sight-threatening and heterogeneous group of diseases. It has been estimated that an average ophthalmologist in general practice will encounter a new case of childhood glaucoma about once every 5 years.1 While patients with childhood glaucomas make up less than 0.1% of ophthalmic patients, they constitute 2% to 15% of populations in institutions for the blind.1 Intraocular pressure (IOP) control is only a small part of the battle to preserve vision in children with glaucoma. The most common reason for visual loss is amblyopia complicated by optic nerve and lens damage, corneal opacification, and ametropia.2,3
The pathogenesis of glaucoma in childhood and the responses of the child’s eye to this disorder are often very different from those seen in older patients. Specialized in formation and techniques for the evaluation and care of children with glaucoma are therefore required. In addition, successful management of the childhood glaucoma patient requires cooperation and support from the entire family, not only from the patient. Because systemic disorders do not infrequently coexist with glaucoma in children, and because most of these patients will require one or more general anesthetics during the management of their glaucoma, the ophthalmologist should work closely with his or her pediatric colleagues in the care of children with glaucoma.
Although many classification schemes have been devised to categorize the various childhood glaucomas, their subdivision into primary and secondary mechanisms can be clinically useful. Primary glaucomas are those resulting from an intrinsic disease of the aqueous outflow pathways and are often genetic in origin. Secondary glaucomas, by contrast, result from disease originating in other regions of the eye or body4–6 (Table 69-1). Both primary and secondary glaucoma may be associated with significant systemic conditions often requiring additional consultation.
Symptoms and Signs
Infants and young children with glaucoma usually present for ophthalmologic evaluation because the pediatrician or parents have noted something unusual about the appearance of the patient’s eyes or behavior. Often, corneal opacification and/or enlargement (a response to elevated IOP) are the signs that signal glaucoma in the infant (Figures 69-1 and 69-2). At other times, the child’s glaucoma may manifest itself as one or more of the classic triad of findings: epiphora, photophobia, and blepharospasm. Photophobia and epiphora result from corneal edema (often with associated breaks in Descemet’s membrane). The baby may be noted to withdraw from light or to bury his or her head against the parent or bedding to prevent exposure to light. Even indoors, the infant may show an apparent reluctance to face upward and may mistakenly be considered shy. Blepharospasm may be yet another manifestation of photophobia, often accompanying epiphora, but without the mucoid discharge so often seen in congenital nasolacrimal duct obstruction7-9 (Figure 69-3).
I. Primary glaucoma
A. Congenital open-angle glaucoma
B. Congenital glaucoma associated with iris defects
C. Juvenile glaucoma
D. Primary glaucomas associated with systemic or ocular abnormalities
1. Associated with systemic abnormalities
a. Axenfeld-Rieger syndrome (iridocorneal goniodysgenesis)
b. Chromosomal disorders
i. Trisomy 13 (13-15 trisomy)
ii. Trisomy and partial deletions of chromosome 18
iii. Turner syndrome
iv. Chromosome 6 (ring syndrome and translocations)
c. Congenital rubella
d. Cutis marmorarta telangiectasia congenita
e. Fetal alcohol syndrome
f. Hepatocerebrorenal (Zellweger) syndrome
g. Infantile glaucoma associated with mental retardation and paralysis
h. Kniest syndrome
i. Marfan syndrome
j. Michel syndrome
I. Neurofibromatosis type 1
m. Nonprogressive hemiatrophy
n. Oculocerebrorenal (Lowe) syndrome
o. Oculodentodigital syndrome
p. Open-angle glaucoma associated with microcornea and absent frontal sinuses
q. Prader-Willi syndrome
r. Rubinstein-Taybi (broad-thumb) syndrome
s. Stickler syndrome
t. Sturge-Weber syndrome
u. Warburg syndrome (skeletal dysplasia)
2. Associated with ocular abnormalities
b. Anterior chamber staphyloma
c. Axenfeld-Rieger syndrome
d. Congenital ectropion uveae
e. Congenital hereditary endothelial dystrophy
f. Congenital microcoria with myopia
g. Congenital ocular melanosis
h. Familial iris hypoplasia
i. Idiopathic or familial elevated episcleral venous pressure
j. Peters’ syndrome
k. Posterior polymorphous dystrophy
II. Secondary glaucoma
A. Traumatic glaucoma
1. Acute onset
a. Angle concussion
2. Late-onset with angle recession
3. Arteriovenous fistula
B. Glaucoma secondary to intraocular neoplasm
2. Juvenile xanthogranuloma
6. Iris rhabdomyosarcoma
7. Aggressive iris nevus
C. Uveitic glaucoma
2. Angle closure
a. Synechial angle closure
b. Iris bombé with pupillary block
D. Lens-induced glaucoma
1. Subluxation-dislocation and pupillary block
a. Marfan syndrome
2. Spherophakia and pupillary block
E. Aphakic glaucoma after congenital cataract surgery
1. Lens material blockage of trabecular meshwork
2. Pupillary block
3. Chronic open angle
F. Steroid-induced glaucoma
G. Neovascular glaucoma
2. Coats’ disease
4. Familial exudative vitreoretinopathy
H. Secondary angle-closure glaucoma
1. Retinopathy of prematurity
5. Persistent hyperplastic primary vitreous
6. Congenital pupillary iris-lens membrane
9. Cornea plana
I. Glaucoma with increased episcleral venous pressure
J. Glaucoma secondary to intraocular infection
1. Acute recurrent toxoplasmosis
2. Acute herpetic iritis
Adapted from Walton DS. Glaucoma in infants and children. In: Nelson B, Calhoun JH, Harley RD, eds. Pediatric Ophthalmology. 3rd ed. Philadelphia, PA: WB Saunders; 1991:175-176.
In children older than 1 year of age, glaucoma usually induces fewer overt signs and symptoms. Children with glaucoma developing between 1 and 4 years of age may not be correctly diagnosed unless glaucoma is suspected from other accompanying ocular or systemic abnormalities.
Children older than 4 years of age with glaucoma most frequently seek examination for decreased distance acuity related to myopia. Significant astigmatism and anisometropia are often also present. An exception to the relatively asymptomatic presentation of glaucoma in older children is secondary glaucoma presenting with an acute rise in IOP to levels sufficient to cause nauseating eye pain, headaches, and even colored haloes around lights (as seen with adults having angle-closure glaucoma). In these children, sudden-onset glaucoma may be the result of traumatic hyphema or of angle-closure glaucoma from lens dislocation or cicatricial retinopathy of prematurity. Less frequently, acute glaucoma develops secondary to other processes.10,11
The manifestations of epiphora, photophobia, and blepharospasm are not unique to infantile glaucoma and also can occur as a result of nasolacrimal duct obstruction, ocular inflammation (uveitis), and corneal injury (eg, abrasion). Corneal edema or opacification may occur in the setting of storage diseases (eg, mucopolysaccharidosis, cystinosis), corneal dystrophies (eg, congenital hereditary endothelial dystrophy or posterior polymorphous dystrophy), birth trauma (with resultant Descemet’s tears), and congenital anomalies (eg, sclerocornea, Peters’ anomaly; Figures 69-4 and 69-5). Isolated corneal enlargement occurs in megalocornea and high axial myopia. Although other nonglaucomatous eye conditions may share one or more signs with childhood glaucoma, care must be taken to rule out glaucoma in each of these cases. For example, glaucoma may complicate uveitis and has been reported in the setting of storage disease, corneal dystrophy, congenital anomalies such as Peters’ anomaly, and megalocornea (Figure 69-6). Glaucoma may also occur coincident with congenital nasolacrimal duct obstruction.12,13
Adapted from Consultation Section. Cataract surgical problem. J Cataract Refract Surg. 2003;29:2261-2268; Tabbara KF, Ross-Degnan D. Blindness in Saudi Arabia. JAMA. 1986;255:3378-3384 and Taylor RH, Ainsworth JR, Evans AR, Levin AV. The epidemiology of pediatric glaucoma: the Toronto experience. J AAPOS. 1999;3:308-315.
Rarely, a child may present after infancy with findings suggestive of primary infantile glaucoma yet have normal IOP. Spontaneous cure in cases of mild primary infantile glaucoma has been described, but remains a diagnosis of exclusion.14,15
The neonatal globe is distensible and enlarges in response to elevated IOP. Stretching may occur in all parts of the infant eye, including the cornea, anterior chamber angle structures, sclera, optic nerve, scleral canal, and lamina cribrosa.16–18 The normal horizontal corneal diameter at birth ranges from 9.5 to 10.5 mm (mean 10 mm), enlarging about 0.5 to 1 mm in the first year of life (Table 69-2).18,19 Under 1 year of age, diameters of 12 to 12.5 mm are suggestive of glaucoma, and a measurement of 13 mm or more at any time in childhood strongly suggests abnormality, as does asymmetry in corneal diameter between eyes in a child. Whereas the cornea may enlarge because of elevated IOP until only the age of approximately 3 years, the sclera may deform in response to increased IOP until approximately 10 years of age. Progressive myopia and astigmatism are therefore often seen in older children with glaucoma.18
Elevated IOP stretches and sometimes breaks Descemet’s membrane, resulting in acute localized corneal edema followed by deposition of new basement membrane into hyaline ridges (called Haab’s striae). These permanent striae are usually fairly horizontal and rarely occur in corneas less than 12.5 mm in horizontal diameter or in children older than 2 years (Figure 69-7). In contrast, breaks in Descemet’s membrane arising from obstetrical trauma (usually involving use of forceps) tend to have a more vertical orientation and to present at birth.20,21
Ultrasonography has been used to record changes in the axial length of eyes in infants with infantile glaucoma. Compared with corneal diameter, however, axial length seems less helpful in the evaluation of glaucomatous infant eyes.22–24
OPTIC NERVE CUPPING
Optic nerve cupping occurs as a result of elevated IOP in childhood glaucoma, but its course (in infants and young children) may be quite different from that seen with adult glaucoma patients. In children with advanced glaucoma, as in adults, loss of neuroretinal rim tissue occurs, especially at the vertical poles of the disc, and the optic cup may extend to the disc margins.15,25,26 In very young patients, one more often sees generalized enlargement of the optic cup with preservation of an intact neuroretinal rim. This pattern of symmetric cupping has been attributed to stretching of the optic canal and backward bowing of the lamina cribrosa in these young patients.15 While this type of optic nerve cupping can occur early and quite rap idly in infants with glaucoma, dramatic reversal of cupping may occur with normalization of IOP (Figures 69-8 through 69-11).15
Large size of the optic nerve cup and asymmetry of cupping between fellow eyes is suggestive but not definite evidence of glaucoma. Illustratively, the cup-to-disc ratio exceeded 0.3 in 68% of 126 eyes with primary infantile glaucoma examined by Shaffer and Hetherington,27 but in only 2.6% of 936 normal newborn eyes examined by Richardson.28 Richardson also reported marked optic cup asymmetry in only 0.6% of normal eyes in his series, contrasted with 89% noted for infants with monocular glaucoma.28
INTRAOCULAR PRESSURE ELEVATION
IOP levels and measurement in children with glaucoma will be discussed next.
The ophthalmic evaluation of the child with suspected glaucoma should address the following objectives:
- Confirming or excluding the diagnosis and etiology of glaucoma
- Determining other ocular anomalies
- Obtaining additional systemic medical information needed to plan for an examination under anesthesia
If one can confidently exclude the diagnosis of glaucoma, or if an older child with glaucoma can be thoroughly examined while awake, examination under anesthesia may not be indicated.
History and Equipment
Taking history from parents and caretakers can be especially valuable in evaluating patients too young to provide any useful verbal information. Information should be gathered regarding pregnancy, labor and delivery, possible signs and symptoms of glaucoma, evidence of systemic abnormality, possible trauma, drug and medication exposure, and pertinent family history. In addition to commonly used office equipment, the use of a portable slit lamp, millimeter ruler, Tono-Pen (Medtronic Solan) and/or Perkins tonometer (Haag-Streit), and Koeppe diagnostic gonioscopic lenses (Ocular Instruments) may be valuable.
Assessment of Vision and Ocular Adnexa
Examination begins with an assessment of the general over all appearance and visual function. In infants, the ability to monocularly fix and follow well and the absence of nystagmus suggest good visual function. Visual acuity can be evaluated with Teller Acuity Cards (Precision Vision) in infancy, and eventually visual fields can be evaluated in children older than about 7 years, respectively (Figure 69-12). The penlight and direct ophthalmoscope are useful instruments for inspecting the adnexa and corneas. It may be useful to delay use of the portable slit lamp until after tonometry has been attempted to maximize the opportunity for measuring IOP in an unanesthetized, undisturbed infant. Dur ing the external examination, one looks for abnormalities (eg, lid malformations) to suggest congenital syndromes that may include glaucoma (Table 69-3) and for signs of lacrimal system obstruction that may explain epiphora. The use of visual evoked potentials is becoming increasing useful in the evaluation of optic neuropathies including glaucoma.
The corneas are examined for abnormalities in shape, size, clarity, symmetry, curvature, and thickness. In the presence of corneal epithelial edema, the corneal surface lacks its normal luster and produces an irregular penlight reflection off its bedewed surface. Because corneal opacification obscures details of the underlying pupil and iris, the relative visibility of these intraocular structures helps to quantify the degree of corneal haze or opacity and is well evaluated with the direct ophthalmoscope. In the worst cases, the cornea appears opaque white or pearly gray and completely hides any view of the pupil. In moderately severe cases, the cornea appears bluish and allows visualization of the pupil but few iris details. Corneal diameter can be estimated using a millimeter rule.29 The examiner may notice a difference in the overall size of one cornea compared to the other, even when corneal diameter measurements seem similar between the fellow eyes. Because the area of a circle varies as the square of its radius, it seems reasonable that the observer’s eye may more easily note differences in area than in diameter of a patient’s 2 corneas (Figures 69-13 and 69-14).
1. External examination (brief)
2. Tonometry (as early as possible after induction and before intubation)
3. Corneal diameter measurement
4. Anterior segment examination
5. Koeppe gonioscopy
6. Fundus examination (optic disc)
7. Optic disc photography
Tonometry and Intraocular Pressure
The best IOP measurements are those obtained on a co operative patient using only topical anesthesia, because IOP may be falsely elevated in a struggling patient or in a patient who is squeezing his or her lids and is often unpredictably altered by systemic sedatives and anesthetics (see the “Examination Under Anesthesia” section). Sometimes, tonometry can be achieved on a sleepy or hungry infant taking a bottle in the parent’s arms (Figure 69-15). Among various instruments used to measure IOP in children, the Perkins applanation tonometer and the Tono-Pen (a handheld Mackay-Marg–type tonometer [Reichert Technologies]) rank highly in terms of accuracy and ease of use in these patients.30,31 The Pulsair (Reichert Technologies), a handheld noncontact tonometer, has also been successfully used to measure IOP in children.30,31 The slit lamp–mounted Goldmann applanation tonometer may be useful in older, cooperative children.
Studies of IOP in unanesthetized infants and children suggest that normal values lie below the mean pressures for normal adults. Pensiero and colleagues (using a Pulsair noncontact tonometer) reported a mean IOP of 9.59 ± 2.3 mm Hg in premature/newborn infants. They found that the mean IOP rose gradually with increasing age of the participants, reaching 13.95 ± 2.49 mm Hg by age 7 to 8 years and remaining essentially constant at that level through the middle teenage years. A mean IOP of 10.11 ± 2.2 mm Hg in normal premature infants was found using a Pulsair tonometer, while Perkins applanation tonometry found the mean IOP of unanesthetized newborns to be 11.24 ± 2.4 mm Hg.32 Others have reported mean IOP using the Perkins tonometer as low as 5.89 and as high as 18 mm Hg in infants and young children.30,31,33 Infants with primary infantile glaucoma commonly present with unanesthetized IOPs between 30 and 40 mm Hg, although occasionally values above or below this range occur. Often, pressure measurements are confounded by a failure to cooperate, requiring measure ment under anesthesia or sedation. The mean IOP in a group of struggling infants has been reported as 28.3 mm Hg by Perkins tonometry, more than twice the value (10.8 mm Hg) obtained in the same infants while quiet.30,31,33 Falsely elevated IOP measurements may either falsely alarm or falsely reassure the examiner. For example, measuring high IOP in both eyes of an intermittently struggling infant with unilateral glaucoma may obscure the actual IOP asymmetry between the eyes. The examiner might erroneously attach less importance to the elevated IOP in the glaucomatous eye, secure in the belief that it matched the falsely elevated IOP in the normal eye (Table 69-4).
Anterior Segment Examination
Following tonometry (or attempts at it), use of the portable slit lamp allows more detailed inspection of the cornea and the remainder of the anterior segment. An abnormally deep anterior chamber or abnormalities of the iris may be additional clues to glaucoma in some cases (eg, aniridia, Axenfeld-Rieger syndrome). Gonioscopy provides the most important anatomic information in the clinical examination regarding the mechanism of the glaucoma and may some times be performed using Koeppe contact lenses and a portable slit lamp or loupes in the office. Angle evaluation is then usually repeated in greater detail under anesthesia.
Fundus examination centers on evaluation of the optic discs, although associated findings such as choroidal hemangioma (suggesting Sturge-Weber syndrome) can add useful information regarding the type of glaucoma present. If infant movements preclude direct ophthalmoscopic evaluation of the discs, indirect ophthalmoscopy using a 14-D lens or a direct ophthalmoscope together with a 20-D condensing lens. As with gonioscopy, disc examination should be repeated under anesthesia, un less normal findings and pressures have obviated this next step. Photography of the optic nerve can be accomplished using such cameras as the Nidek handheld fundus camera (Gamagori).
Refraction and Perimetry
Determination of refractive errors using cycloplegic retinoscopy or automated refraction can be helpful, especially when they are asymmetric in the setting of unilateral or aphakic glaucoma; in this case, relative myopia of the affected eye or increasing myopia supports the diagnosis of glaucoma. Older children (beginning at 6 or 7 years of age) can also undergo subjective visual field examinations, allowing assessment of the extent of initial field loss as well as stability of the remaining visual field over time (as one attempts to control the glaucoma). Goldmann visual field testing is our choice for younger children because the tester may constantly encourage the patient and may briefly suspend testing when fixation wanders or attention wanes. Teenaged patients often perform well on standard automated perimetry programs, such as the Humphrey 24-2.
When one or more findings of the initial examination confirm or raise suspicions of childhood glaucoma, the ad ministration of anesthesia is usually justified, both for a more complete examination as well as for probable surgical intervention.
EXAMINATION UNDER ANESTHESIA
General Anesthesia Versus Office Sedation
General anesthesia in the operating room has advantages over sedation or anesthesia administered elsewhere because it allows surgical intervention without further delay once the diagnosis of glaucoma is confirmed. An exception may be the use of chloral hydrate to facilitate office tonometry in the following patients:
- Patients felt unlikely to actually have glaucoma
- Patients in whom the need for further surgical intervention seems unlikely or in whom decision making depends heavily upon obtaining IOP unaltered by inhaled anesthetics
Chloral Hydrate Sedation
Oral chloral hydrate sedation has been used by clinicians (pediatricians, pediatric ophthalmologists, radiologists, and dentists) for many years and may be particularly useful to the ophthalmologist when IOP determination is pivotal to decision making in the office setting. Chloral hydrate seems to minimally alter IOP recorded in children.32 It has been stated that chloral hydrate is an effective short-term sedative that infrequently causes toxicity when administered orally at appropriate dosages with no serious systemic side effects with oral doses as high as 100 mg/kg for the first 10 kg, then 50 mg/kg for each additional kg body weight.32 Recently, major medical centers have begun to formalize the setting under which conscious sedation may be performed (in compliance with JCAHO standards). Key suggested guidelines include the following:
- Preprocedure evaluation of the patient by a physician prior to administration of medication
- Informed consent to include risks of conscious sedation
- Minimum of 2 personnel avail able (the operator, or physician performing the examination, as well as the monitor, or assistant trained to monitor the patient)
- Patient monitoring (and documentation on flowsheet) to include continuous pulse oximetry as well as other vital signs and level of consciousness (recorded at least every 10 minutes)
- Minimum equipment available to include emergency airway equipment (eg, oxygen and suction), pulse oximeter, blood pressure monitor, and cardiac arrest cart
In many centers, this may be so burdensome as to preclude outpatient sedation in favor of only examination under anesthesia.
Sequence of Examination Under Anesthesia
A logical sequence for examination under anesthesia begins with a brief external examination followed by IOP measurements (Figure 69-16). Tonometry should be performed during the earliest possible moments after induction and before endotracheal intubation (Figures 69-17 through 69-19). One may then proceed with corneal diameter measurements followed by slit-lamp examination of the anterior segment and Koeppe gonioscopy and funduscopy. Pupil dilation is performed only if results of the aforementioned examination are reassuring enough to obviate surgery. In this case, optic disc photography is also helpful in following children with glaucoma. Great care should be taken during administration of anesthesia and examination under anesthesia to avoid drying or damage to the corneal epithelium, as this may increase the difficulty and risk of subsequent surgical intervention (especially goniotomy).
Tonometry Under Anesthesia and Sedation
An unfortunate consequence of the anesthesia required for adequate examination is that IOP measurements are variably altered by sedatives, narcotics, and inhaled anesthetic agents (see Table 69-4). There are no to minimal changes in IOP recorded after high-dose oral chloral hydrate (100 mg/kg for the first 10 kg, then 50 mg/kg for each additional kg body weight) was given to a group of 50 normal children under 6 years, as well as to a smaller group of children with glaucoma. The mean IOP under chloral hydrate for normal eyes was 5.6 mm Hg by Perkins tonometry and 14.7 mm Hg by digital pneumotonometry, while glaucomatous eyes measured 19.5 and 28.5 mm Hg, respectively. Others have reported IOP in nonglaucomatous children under chloral hydrate ranging from 11 to 17 mm Hg by Mackay-Marg tonometry.32,34 Ketamine has been variously reported to raise and to minimally affect the pressure in children.34
Although there are conflicting reports, inhaled anesthetics (eg, halothane and enflurane) are generally agreed to lower IOP measurements variably.35–37 The normal IOP in an infant under halothane anesthesia is reported to be 9 to 10 mm Hg, with a pressure of 20 mm Hg or greater considered suspicious for glaucoma.35–37 IOP elevation is consistently reported after administration of succinylcholine as well as with tracheal intubation.38 Even administration of 100% oxygen alone slightly lowers IOP (as does breathing nitrous oxide-oxygen mixtures).38
Fortunately, although IOP measurements influenced by sedatives and anesthetics may vary greatly from true awake readings, high preanesthetic IOPs usually remain in an abnormal range, even under anesthesia. Asymmetric IOP measurements between fellow eyes more reliably indicate abnormality than do borderline IOP readings in both eyes taken under anesthesia. IOP measurements under anesthesia should never be taken as the sole proof of glaucoma; if they are elevated in the setting of an otherwise negative glaucoma evaluation, conservative management and close observation are warranted. In contrast, when corneal and optic nerve abnormalities suggest glaucomatous damage, low IOP readings may be cause for repeat examination prior to surgical intervention, but should not provide false reassurance (see Table 69-4).
Ophthalmologists may have ready access in the operating room to Schiotz tonometry but not to the Perkins applanation or Tono-Pen tonometers. While IOP measurement with Schiotz tonometry may be employed during examination under anesthesia, this technique has definite disadvantages. Because indentation tonometry is influenced by both scleral rigidity and corneal curvature and thickness, IOP recorded in infants using Schiotz tonometry may differ significantly from that recorded by applanation, depending upon the size and thickness of the cornea. For a given Schiotz pressure (1955 calibration), the corresponding applanation IOP may be from 5 mm Hg higher to 7 mm Hg lower.
Anterior Segment Examination
Corneal diameter measurements under anesthesia are made using a caliper ordinarily used for strabismus and other surgeries with similar precision. Anterior segment examination with a portable slit lamp should be performed.
Gonioscopy Under Anesthesia
If the cornea is clear enough to permit it, gonioscopy should be performed using Koeppe gonioscopy lenses of proper size, together with a handheld binocular micro scope and Barkan focal illuminator (Reichert Technologies) or a portable slit lamp (Figures 69-20 through 69-22). Placing a Koeppe lens onto each eye at the same time facilitates comparison of the angle features in the fellow eyes.
Gonioscopic findings in normal infants and young children differ significantly from those of adults. Of the visible angle structures, the uveal meshwork (extend ing forward from peripheral iris onto corneoscleral mesh work) differs most greatly between the 2 age groups. In normal infants younger than 1 year of age, the uveal meshwork is so delicate that the juncture of scleral spur and ciliary body band appears crisp and distinct. In later years, the uveal meshwork loses its early homogeneous, sheet-like appearance and becomes a more coarse, lacy, and open structure. In dark-eyed individuals, pigmentation of the uveal meshwork with increasing age increases visibility of this lacy structure.
The iris in infantile glaucoma often shows a more anterior insertion than that of the normal infant, with altered translucency of the angle face producing an indistinct ciliary body band, trabecular meshwork (TM), and scleral spur. The scalloped border of the iris pigment epithelium and the meshwork itself may be unusually prominent in infantile glaucoma, visible through the translucent peripheral iris stroma as if viewed through a “morning mist.”39,40 Juvenile open-angle glaucoma patients usually demonstrate a normal-appearing open angle, often with a prominent, lacy uveal meshwork.
Fundus Examination and Possible Surgery
After gonioscopy, direct ophthalmoscopy through a Koeppe lens (and undilated pupil) usually affords an excellent view of the optic nerves. At this point, if sufficient evidence suggests glaucoma, one may proceed directly to appropriate surgical intervention. Otherwise, if glaucoma is excluded or conservative management is indicated (as in the case of borderline pressures in the absence of suggestive corneal, angle, or optic nerve abnormalities), the pupils can be dilated (Figure 69-23). Pupil dilation facilitates photographic documentation of disc cupping, as well as cycloplegic refraction (although the latter can usually be performed with equal ease in the office setting, obviating prolonged anesthesia). Examination under anesthesia can often be accomplished entirely without endotracheal intubation in slightly older infants and children, until the need for surgical intervention has been confirmed in the operating room. If surgery is deferred, wake-up and recovery time for the patient may be minimized.
VISUAL FIELD TESTING IN CHILDREN
Standard Goldmann or automated perimetry can be performed on children with glaucoma, but like all clinical evaluations in the pediatric population, are age dependent.37 Most developmentally normal children are able to provide valid and reliable data on perimetry at about 10 years of age, albeit many need practice sessions. In a group of 13 children between the ages of 4 and 14 years with congenital glaucoma and 10 age-matched healthy children, localized visual field defects (eg, paracentral scotoma, nasal step, and arcuate scotoma) were determined.38 Specific visual field defects were found only in bilateral cases.38 Paracentral scotoma was found in 1 of 12 eyes with bilateral congenital glaucoma.38 Nasal steps were found in 6 of 12 eyes with bilateral congenital glaucoma.38 Arcuate scotoma were found in 4 of 12 eyes with bilateral congenital glaucoma.38 In another report, long-term functional results in 102 eyes of 59 patients with childhood glaucoma with specific reference to the pattern of optic nerve damage were studied.39 Optic disc photography and quantitative perimetry were used to judge the degree of damage that had been sustained.39 There was a predilection for initial visual field damage in the arcuate area followed by further arcuate and nasal field loss similar to the pattern of visual field loss seen in adult glaucoma. In children, as in adults, neural tissue appeared to be lost preferentially at the vertical disc poles.39 The selective pattern of glaucomatous optic nerve damage seemed not to depend upon the age of the optic nerve structures.39
OPTICAL COHERENCE TOMOGRAPHY IN CHILDREN
This is an exciting clinical and research tool that has a tremendous impact on the understanding, diagnosis, and treatment of glaucoma in infants and children. Other chapters in this book discuss this technology in detail. We have been able to acquire reliable Stratus optical coherence tomography (OCT; Carl Zeiss Meditec) data from outpatients as young as 3 years of age. Now that handheld OCT technology is becoming available, the use of this in the operating room will assist the clinician in diagnosis and management. Some early reports on OCT and children have been completed. In one report, 156 eyes of 79 patients were enrolled. Fifty-two eyes (33.3%) met criteria for glaucoma and 104 (66.7%) were normal. There were 44 female (55.6%) and 35 male (44.3%) participants whose ages ranged from 3 to 17 years old. The OCT-3 (Carl Zeiss Meditec) was used to obtain a fast macular thickness map as well as a fast retinal nerve fiber layer map of each eye. There was a statistically significant difference in macular thickness and nerve fiber layer thickness when normal eyes were compared against those with glaucoma in all quadrants studied (all P ≤ .001). The authors concluded that OCT may prove valuable in the early diagnosis of glaucoma and that the difference between normal and glaucomatous eyes in children is similar to that reported in adults41 (Figures 69-24 through 69-26).
PRIMARY CONGENITAL OPEN-ANGLE GLAUCOMA
Primary congenital open-angle glaucoma (trabeculodysgenesis), commonly referred to as congenital glaucoma or infantile glaucoma, is a specific inherited developmental defect of the TM and anterior chamber angle in which the angle appears to be open in the sense that the iris and corneoscleral TM are separated.5,42 It is a significant cause of childhood blind ness and is the most common type of glaucoma in infants. Characteristically, it manifests itself in the neonatal or infantile period with clouding and enlargement of the cornea, buphthalmos, epiphora, photophobia, and blepharospasm. Because of its relative rarity, it is often misdiagnosed and confused with inflammatory or infectious processes affecting the conjunctiva, cornea, and lids.13,43 Approximately 25% of patients are diagnosed at birth, more than 60% are diagnosed by age 6 months, and more than 80% will have their onset within the first year of life.13,43 Primary infantile glaucoma can occur in later childhood, then commonly termed juvenile glaucoma. This type is usually not associated with buphthalmos and corneal enlargement, although these can continue to occur until ages 6 to 8 years.44
Primary congenital glaucoma can be distinguished from secondary infantile glaucoma by the absence of easily recognizable congenital abnormalities of the iris (such as aniridia), obvious obstructions of the TM (such as iridocorneal dysgenesis), and other metabolic inflammatory or congenital diseases of the eye (Figures 69-27 through 69-31).
Primary infantile glaucoma occurs in approximately 0.01% of children (1 out of 10,000 births) and results in blindness in 2% to 15% of individuals (Table 69-5).9,10 It is bilateral in 60% to 80% of patients and occurs more frequently in males (65%) than females (35%).45-47 There is no racial or geographic predilection.