Ординатура / Офтальмология / Английские материалы / The Pediatric Glaucomas_Mandal, Netland_2006

recessive mode of inheritance. No significant sexual or racial predilection for aniridia has been described.

Four phenotypes of aniridia have been identified on the basis of associated ocular and systemic abnormalities.67 One phenotype is aniridia with predominant iris changes and normal visual acuity. Another phenotype is aniridia associated with foveal hypoplasia, nystagmus, corneal pannus, glaucoma, and reduced vision. The third type is aniridia associated with Wilm’s tumor (the aniridia–Wilm’s tumor syndrome) or other genitourinary anomalies. The fourth phenotype is aniridia associated with mental retardation.

Clinical manifestations

Decreased vision is generally associated with aniridia.68–72 The majority of ophthalmic manifestations occurring with aniridia are the result of various associated ocular abnormalities, including cataracts, glaucoma, corneal dystrophy, nystagmus, photophobia, strabismus, ectopia lentis, optic nerve hypoplasia, and poor foveal reflex. Poor foveal development may occur in the postnatal period in some cases. The ophthalmic complications associated with aniridia, especially cataracts, glaucoma, and corneal opacification, are often responsible for progressive loss of vision. Photophobia is often present in affected patients, and is due to absence of a normal pupil and excessive light stimulation. A characteristic facial expression in many children is narrowing of the palpebral fissure and furrowing of the brow (Fig. 7.7).73,74

There is variability in the iris configuration in aniridia, ranging from almost total absence to mild hypoplasia of the iris (Fig. 7.8). Although early reports described cases in which the iris appeared to be completely missing clinically, complete gonioscopic examination was not performed. Ocular colobomas associated with aniridia have been reported among individuals in the same family in the early literature. Aniridia is still considered by some to be one of the colobomatous disorders.75

Congenital glaucoma with or without buphthalmos is rare in infants with aniridia; however, the reported incidence of glaucoma later in childhood is 6% to 75%. The higher

Figure 7.7 Aniridia. Photophobia with narrowing of the palpebral fissure and furrowing of the brow.

figures were reported from glaucoma centers and probably represent an overestimation of the true incidence because of the referral nature of the institutions.

Routine gonioscopic examination is important to detect anatomic changes in the angle structures that may progress to angle closure. During the first few years of life, the trabecular meshwork appears open and is not covered by iris tissue. Grant and Walton found that progressive change in the angle structures may occur during the first two decades of life in those patients who will develop glaucoma.74,76 These changes include attachment of the rudimentary iris to an anterior position, thereby covering the filtration area of the trabecular meshwork. Most of the filtration area is covered by the iris remnant in patients who will develop glaucoma. Glaucoma secondary to intumescent lens changes or ectopia lentis has been reported in aniridia.

Ectopia lentis has been reported, ranging from 0% up to 56% of patients with aniridia. Failure to detect mild subluxations of the lens may be the reason ectopia lentis has not been reported by some investigators. Hypoplastic ciliary processes have been reported in pathologic specimens from patients with aniridia, but no defects in zonules or the pars plana have been reported.73

Cataracts occur frequently and at a young age in aniridia.67,70 Lens opacities develop in 50% to 85% of patients, usually during the first two decades of life. Although many aniridics have poor vision during adolescence secondary to foveal

hypoplasia and corneal opacification, cataracts may further compromise vision. Frequently, at birth, small anterior and posterior lens opacities may be noted, but these do not usually cause significant visual difficulty. Cortical, subcapsular, and lamellar opacities often develop by the teenage years and may require lens extraction.

Corneal abnormalities are common in aniridia. In a high proportion of patients, a corneal pannus and opacity begins in the peripheral cornea in early life and advances towards the center of the cornea with increasing age. Because the corneal abnormality in aniridia is vascularized and inflamed, it is not included among the group of diseases known as dystrophies. Microcornea77 has been reported in association with aniridia. Increased central corneal thickness has been reported in patients with aniridia,78 which may lead to inaccuracy (overestimation) of applanation tonometry measurement of intraocular pressure in some patients.

Layman and coworkers70 suggested that the majority of aniridia patients have optic nerves that are hypoplastic. However, optic nerve hypoplasia is often difficult to document in the aniridia patient because of nystagmus and poor visibility secondary to cornea and lens involvement. Poor retinal and macular development seen in many aniridics probably contributes to or is entirely responsible for the optic nerve hypoplasia.

Pendular nystagmus is present in the majority of patients with aniridia. Most investigators believe the nystagmus is secondary to macular hypoplasia.67,70 Strabismus is common in aniridic patients, often an esotropia. High refractive errors are common and a careful cycloplegic refraction is necessary in affected children. Asymmetric visual loss in aniridic children may occur from amblyopia secondary to strabismus or anisometropia. Aniridia has also been reported in association with Marfan syndrome, Hallerman–Streiff syndrome, and sometimes with ptosis.

Different mechanisms have been proposed for the elevation of intraocular pressure in aniridic patients. There may be abnormal function of the anterior chamber angle, with or without absence of Schlemm’s canal. Peripheral anterior synechiae may cause secondary angle closure.74,76 Secondary angle closure may develop following cataract extraction or glaucoma procedure. The anterior chamber angle may be open, with elevation of intraocular pressure. Unsuccessful argon laser trabeculoplasty may also be associated with elevated intraocular pressure.

Differential diagnosis of aniridia

Aniridia must be differentiated from other disorders, including iris coloboma (typical or atypical), corectopia, iridocorneal endothelial syndrome, anterior chamber cleavage syndromes, and colobomatous microphthalmia.

Management of glaucoma in aniridia

Conventional medical therapy may control the intraocular pressure initially, but eventually proves to be inadequate in

most cases. Aniridic glaucoma requiring surgical treatment occurs in up to half of patients. Goniotomy is of limited value in advanced cases, but early goniotomy to separate the iris and the trabecular meshwork may prevent the development of glaucoma.66,76,79 Initial trabeculotomy80 or trabeculotomy combined with trabeculectomy81 may also be effective. Trabeculectomy alone is often unsuccessful,82 although trabeculectomy with mitomycin C may be a useful option.83 A glaucoma drainage implant may have a lasting benefit in some cases.82,84 Cyclophotocoagulation may have a role in some patients with intractable glaucoma as a temporizing or adjunctive measure.85

Glaucoma in the phakomatoses

The phakomatoses (phakos = birthmark) or disseminated hamartomatoses, are a group of ophthalmologically important hereditary disorders exhibiting variable penetrance and expressivity. These disorders are characterized by the formation of hamartias and hamartomas in the eye, central nervous system, skin, and viscera.

The classic features of the phakomatoses include nontumorous growths on the skin or mucous membranes that arise from cells normally found in the tissue at the involved site of growth (hamartias). Also, there are localized tumors arising from cells normally found in the tissue at the site of growth (hamartomas). There may be true neoplasms originating from undifferentiated embryonic cells of differentiated mature cells as well as other associated congenital abnormalities. In phakomatoses, derivatives of all three embryonic layers may be affected.

Some of the phakomatoses are commonly associated with glaucoma, whereas others are occasionally or rarely associated, or not associated with glaucoma (Table 7.2). Sturge–Weber syndrome (encephalotrigeminal angiomatosis) is commonly associated with glaucoma (Fig. 7.9). Glaucoma is occasionally a manifestation of other phakomatoses, including neurofibromatosis (Von Recklinghausen), angiomatosis retinae (Von Hippel–Lindau), and oculodermal melanocytosis (nevus of Ota, Fig. 7.10). Glaucoma in the phakomatoses86 can develop through a number of different mechanisms, even within a single disease entity.

Table 7.2 Glaucoma associated with phakomatoses

Commonly associated with glaucoma

Encephalotrigeminal angiomatosis (Sturge–Weber syndrome)

Occasionally associated with glaucoma

Neurofibromatosis (Von Recklinghausen)

Angiomatosis retinae (Von Hippel–Lindau)

Oculodermal melanocytosis (nevus of Ota)

Rarely associated with glaucoma

Basal cell nevus syndrome

Tuberous sclerosis (Bourneville)

Klippel–Trenaunay–Weber (in pure form)

Diffuse congenital hemangiomatosis

Unassociated with glaucoma

Ataxia–telangiectasia (Louis–Bar)

Racemose angioma of the retina (Wyburn–Mason)

Diagnosis of glaucoma is frequently straightforward, based on the presence of elevated intraocular pressure, buphthalmos, and other signs of glaucoma in infancy or early childhood, and based on elevated intraocular pressure in children and adults. Optimal treatment, however, often depends on the determination and analysis of the underlying mechanisms of the glaucoma.

Although there is no universal mechanism to explain the pathogenesis of glaucoma in the phakomatoses, there

are similarities among the syndromes. Tissue hypertrophy and developmental abnormalities have been postulated to cause ocular hypertension in both neurofibromatosis and encephalotrigeminal angiomatosis, or melanocytes in oculodermal melanocytosis. A ciliary body or choroidal neurofibroma or an iris hemangioma may cause the iris to obstruct the angle. Neovascular glaucoma has been reported in neurofibromatosis, encephalotrigeminal angiomatosis, angiomatosis retinae, and tuberous sclerosis. Elevated

episcleral venous pressure may occur in encephalotrigeminal angiomatosis, which may increase the risk of complications associated with glaucoma surgery.

Metabolic diseases

Oculocerebrorenal syndrome of Lowe

Oculocerebrorenal syndrome (Lowe syndrome) features increased organic aciduria, systemic acidosis, ketonuria, glycosuria, proteinuria, emotional irritability, and mental retardation. The blood shows a decreased carbon dioxide and a decrease in serum phosphorus. The inheritance pattern is X-linked recessive, and mothers who are carriers of the trait may have characteristic punctate lens opacities.

The ophthalmic findings include congenital cataracts, nystagmus, blue sclera, and, in patients with glaucoma, corneal edema and bilateral corneal opacification (Fig. 7.11). Glaucoma is noted in approximately two-thirds of the patients. Patients may have microphthalmia, which may present with elevated intraocular pressure. The mechanism of the glaucoma is related to faulty development of the filtration angle. Gonioscopy reveals minor anatomic defects, including poor visualization of the scleral spur and a narrow ciliary body band.

Ophthalmic treatment includes cataract extraction and control of glaucoma. Glaucoma may respond to goniotomy or trabeculotomy, although filtering surgery may be required. Comanagement with a pediatrician is required for the metabolic disorder.

Homocystinuria

Homocystinuria is a metabolic abnormality with a defect in the enzyme cystathionine synthetase. It is inherited as an autosomal recessive disorder. The patients are characteristically lightly pigmented with blond hair and blue eyes. Ocular abnormalities include ectopia lentis,87 retinal detachment, and glaucoma. The lens is usually subluxated inferiorly, but may move anteriorly, resulting in pupillary block glaucoma.

Figure 7.11 Lowe’s syndrome (oculocerebrorenal syndrome). This infant had bilateral cataracts and renal tubular dysfunction (Fanconi syndrome). He subsequently manifested elevated intraocular pressure, hypotonia, frontal bossing, and developmental delay. His mother had punctate lens opacities, most apparent after dilation of the pupil with retroillumination.

When the dislocated lens causes angle closure, treatment consists of dilatation of the pupil and peripheral iridectomy to break the pupillary block. If possible, iridectomy should be done with laser, because patients may have an increased risk of thromboembolic phenomena with general anesthesia. Lens extraction is required if the lens has dislocated into the anterior chamber.

Sulfite oxidase deficiency

Sulfite oxidase deficiency is characterized by severe neurological abnormalities, mental retardation, and dislocation of the lens. The syndrome is due to defective activity of the enzyme that normally catalyzes the conversion of sulfite to sulfate. Death usually occurs in early childhood. Glaucoma is managed in the same fashion as in homocystinuria.

Persistent hyperplastic primary vitreous

Persistent hyperplastic primary vitreous typically occurs unilaterally in a microphthalmic eye. It results from failure of atrophy of the primary vitreous and its vascular structures. A retrolental fibrovascular membrane can attach to the posterior aspect of the lens, as well as to the ciliary processes. The membrane may appear as a whitish mass in the pupil, giving rise to leukocoria.

Secondary angle closure glaucoma can occur because of swelling of the lens and contraction of the retrolental membrane, which pushes the lens further forward. Hemorrhages into the eye may also result in glaucoma.

Removal of the lens and membrane may prevent closure of the angle and is indicated if the angle is narrowing. Peripheral iridectomy can delay the need for lens extraction, but the angle must be observed carefully for progressive closure.

Retinopathy of prematurity (retrolental fibroplasia)

Retinopathy of prematurity is often associated with prematurity of the newborn and oxygen therapy. It is typically bilateral and fairly symmetric, although it can present asymmetrically. Occasionally the disease occurs in full-term infants and in those without any oxygen therapy.

Retinal blood vessels reach the ora serrata nasally at eight months gestation but do not vascularize the temporal retina until shortly after birth. The retinal vessels only appear susceptible to oxygen damage before their complete vascularization, which accounts for the propensity for retrolental fibroplasia to occur temporally.

The initial effect of oxygen on the retinal blood vessels is vasoconstriction. When the infant is placed in normal air, vascular endothelial proliferation may occur adjacent to vessels that were constricted and closed during oxygen therapy. Regression is common in the earlier stages of the process, but with more advanced disease neovascularization may develop through the internal limiting membrane onto the retinal

surface and into the vitreous. If these advanced stages are reached, vitreous hemorrhage and fibrosis, and retinal detachment may occur.

The development of these retrolental fibrotic membranes can cause a forward displacement of the lens and iris, which may lead to angle closure glaucoma, usually with some degrees of pupillary block.88 Iridectomy can be helpful in relieving the pupillary block.89 Lens removal with removal of the retrolental membranes may be indicated in selected cases.

Chromosomal anomalies

Several types of chromosomal defects are often associated with developmental glaucoma. These include Trisomy 21 (Down syndrome), Trisomy D (13–15) syndrome, Trisomy 18 (Edward syndrome), and Turner syndrome (XO). Multiple ocular and systemic defects may be evident, in association with a large variety of presentations. The necessity for surgical and medical management must be individualized to each patient because some of these patients have a limited life expectancy. If isolated trabeculodysgenesis is evident on examination, a goniotomy or trabeculotomy would be the initial procedure.

Broad thumb syndrome (Rubenstein–Taybi syndrome)

Broad thumbs and great toes are the most evident abnormalities in this syndrome. They may occur in association with mental and motor retardation, lid colobomata, cataract, as well as congenital glaucoma.90 Large physiologic optic disc cupping without glaucoma also can be seen in these patients. In patients with glaucoma, goniotomy or trabeculotomy can be successful in controlling the glaucoma.

Conclusion

The diagnosis and management of some of the important secondary congenital glaucomas have been discussed in this chapter. In the management of the secondary congenital glaucomas, identification of the underlying mechanism for the glaucoma determines the appropriate therapeutic strategy. The necessity for surgical and medical management must be individualized to each patient, and a multidisciplinary approach must be undertaken whenever necessary.

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Introduction

Overview of clinical management

Factors influencing therapeutic decisions

Conclusion

Introduction

The primary objective in the management of the developmental glaucomas is to normalize and permanently control the intraocular pressure, thereby preventing loss of visual acuity, preserving visual field and ocular integrity, and stimulating the development of binocular stereoscopic vision. In 1939, J. Ringland Anderson1 stated that ‘the future of children with hydrophthalmia [primary infantile glaucoma] is bleak... with little hope of preserving sufficient sight to permit the earning of a livelihood.’ Today a much more optimistic outlook has been reached. It is rare to see a neglected patient with a poor outcome (Fig. 8.1). The improved prognosis of the developmental glaucomas is due to accurate and early diagnosis, as well as prompt and effective treatment.

Glaucoma in the infant is an uncommon disease, but the impact on the visual development is profound. Any vision during the child’s formative years is worth fighting for, even if it is ultimately lost in severe cases, because appropriate and early therapy of this relatively uncommon condition may improve the child’s visual future. This chapter provides an overview of the management of the developmental glaucomas, and highlights the factors influencing therapeutic decisions in the child with glaucoma.

Overview of clinical management

Medical therapy usually provides a supportive role to reduce the intraocular pressure temporarily, to clear the cornea, and to facilitate surgical intervention. Most patients who require long term medical therapy have severe disease that has not responded to surgical therapy. Medical therapy for pediatric glaucomas is described in detail in Chapter 9. Laser therapy has a limited role in the treatment of developmental glaucomas. The effective and definitive form of treatment of most of the developmental glaucomas is surgical. Primary surgical treatment is usually with goniotomy or trabeculotomy, although combined trabeculotomy and trabeculectomy may be useful in certain populations with a high risk for failure of goniotomy or trabeculotomy (Chapter 10). Some patients will not respond well to initial surgery for developmental glaucoma. As described in Chapter 12, these patients may respond to a variety of surgical treatments, including trabeculectomy with antifibrosis drugs, glaucoma drainage implants, and cyclodestructive procedures.

Factors influencing therapeutic decisions

The choice of surgical therapy in the developmental glaucomas is dependent on a variety of factors (Table 8.1). Most important of these is the structural defect2,3 associated with the elevated intraocular pressure. In addition, age, corneal clarity, and associated systemic syndromes can influence the choice of therapy.

Figure 8.1 Untreated congenital glaucoma. Untreated patients are uncommon, and the prognosis of congenital glaucoma has improved with more effective diagnosis and treatment.

Structural defects

Isolated trabeculodysgenesis is the hallmark of primary developmental glaucoma. In most instances, abnormal development of the trabecular meshwork increases the resistance

Table 8.1 Factors influencing clinical treatment

Structural defects

Age

Systemic syndromes

Corneal clarity

Severity of glaucoma

Corneal diameter

to aqueous outflow, which causes the elevated intraocular pressure. This condition is highly responsive to both goniotomy and trabeculotomy ab externo. The classic operation for the treatment of primary infantile glaucoma is Barkan’s goniotomy,4 a procedure which has changed little since its original description. In recent years, however, there has been a trend toward trabeculotomy ab externo.5–7

In iridotrabeculodysgenesis, the success rate for goniotomy and trabeculotomy decreases. When the only iris defect is hypoplasia of the anterior stroma, good response to goniotomy or trabeculotomy has been noted. However, when the iris defect includes abnormal vessels that appear to wander somewhat irregularly across the surface of the iris, then the prognosis is poor. In such cases, multiple surgeries are usually needed. If the angle can be easily visualized, goniotomy may be attempted, but trabeculotomy is probably the better initial procedure of choice.

When there are extensive iris structural defects, careful evaluation of the angle is necessary. In aniridia, Grant and Walton8 noted gradual folding up of the peripheral stump of the iris over the trabecular meshwork forming the peripheral anterior synechia that blocks aqueous outflow. They believe this is a common cause of glaucoma in aniridia, and recommend prophylactic goniotomies to prevent the adhesion. Hoskins and associates frequently noted an anterior insertion of iris stroma in patients with aniridia, which is not an acquired process but present at birth. The stroma of the stump of the iris seems to sweep up across the angle. In the presence of this developmental anomaly, we prefer trabeculotomy ab externo for the initial operation when medical therapy fails.

In iridocorneotrabeculodysgenesis, the prognosis for surgical treatment is poor. Often medical therapy is unsuccessful, and surgical intervention becomes necessary. Ab externo combined trabeculotomy and trabeculectomy may be useful as the initial operation in these patients to control the intraocular pressure.

Angle-closure glaucoma is uncommon in childhood, but is important to recognize when it occurs. The surgical treatments for open-angle glaucoma are not effective for angleclosure glaucoma. Closure of the angle may be secondary to an underlying problem, which should be corrected.

Systemic syndromes

In Sturge–Weber syndrome, the glaucoma can be present at birth or appear at anytime from infancy to adulthood. The mechanism of the glaucoma remains controversial9,12 and these patients show varying response to surgical therapy according to their age. When glaucoma is present in infancy, the developmental anomaly that obstructs aqueous outflow may predominate, which resembles the situation in primary congenital glaucoma.9 Many surgeons prefer goniotomy or trabeculotomy as the operation of choice but report that the rate of success is consistently lower than that with primary congenital glaucoma.10,11

When glaucoma in Sturge–Weber syndrome has its onset in later life, it is thought to be primarily due to elevated episcleral venous pressure.9 The angle defect is less severe and is sometimes minimal. In such patients, medical therapy should be tried first. If medical therapy fails, some surgeons feel that filtering procedures, such as trabeculectomy, should be performed on these eyes.12–14 We often use a technique combining ab externo trabeculotomy and trabeculectomy in such cases. The trabeculotomy is performed to remove the possible obstruction to aqueous outflow by a congenital angle deformity, while the trabeculectomy is included to bypass the episcleral venous system. In other words, the combined procedure may address both possible mechanisms of glaucoma association in this disease.15

There may be a rapid accumulation of a massive amount of suprachoroidal fluid during the operative procedure (Fig. 8.2).11,14 This will produce flattening of the anterior chamber, hardening of the globe, and difficulty in repositing a prolapsed iris when the sclerotomy is made. After the iridectomy is done, it may be difficult to reposit ciliary processes that rotate anteriorly into the sclerostomy, and vitreous may be lost. These complications can be avoided or minimized if, before entering the anterior chamber, two posterior radial sclerotomies or a triangular sclerotomy are made in the inferior quadrants of the globe. This enables the suprachoroidal effusion to drain out of the eye as it forms.

Age

The age of the child at the onset of glaucoma is also a factor in choosing the appropriate therapy. In general, children under the age of 3 years are best treated surgically. Those with isolated trabeculodysgenesis respond well to both goniotomy and trabeculotomy ab externo. It has been observed that goniotomy is less successful after the age of 3 years, whereas trabeculotomy may be successful until later in life.

Children over 3 years of age deserve a trial of medical therapy unless the specific defect of trabeculodysgenesis is seen (including an anterior insertion of the iris, a thickened trabeculum, or a wrapround type of anterior iris stromal insertion). Such patients may be treated with trabeculotomy ab externo.

Figure 8.2 Choroidal effusion during the immediate postoperative period in a patient with Sturge–Weber syndrome.

To help avoid the complications of conventional glaucoma surgery in eyes with increased episcleral venous pressure, filtration techniques that do not require entry into the anterior chamber have been recommended by some surgeons. These include sinusotomy16 and non-penetrating trabec-

ulectomy with or without Nd:YAG laser trabeculotomy.16,17

Oculocerebrorenal syndrome of Lowe is a rare syndrome, which may be associated with glaucoma and trabeculodysgenesis.18 Hemorrhage may accompany surgery and, therefore, medical therapy should be tried initially. The success of surgery is reduced compared with the success

for primary developmental glaucoma.

In homocystinuria, secondary glaucoma associated with angle closure may occur, due to subluxation of the lens. Laser or surgical iridotomy or lens removal are surgical options in this situation. Intravascular thrombosis has been reported

with anesthesia in patients with homocysteinuria.19

In trisomy 13, congenital glaucoma resulting from poor differentiation of the angle structures has been reported.20 However, most of these patients die within the first few weeks of life, with only 18% of patients surviving the first year. Thus, in this syndrome and in others that have a high mortality rate, surgical intervention is warranted only in eyes that have a good prognosis and patients in whom longevity is likely to be good. Consultation with the pediatrician is

useful in deciding management for these patients.

In chronic childhood uveitis, goniotomy is a useful initial surgical procedure. Freedman and coworkers described the efficacy of goniotomy in 12 patients with childhood uveitic glaucoma and found an overall success of 75% with a mean follow-up of 32 months.21 Ho and coworkers reported experience with 54 goniotomies performed in 40 eyes of 31 patients, the majority with a diagnosis of juvenile rheumatoid arthritisassociated uveitis.22 Overall surgical success was achieved in 29 eyes (72%). Surgical outcome was adversely affected by increased age, peripheral anterior synechiae, prior surgeries, and aphakia.

Figure 8.3 Corneal edema due to elevated intraocular pressure in a patient with aniridia. The opacity of the cornea is associated with a poor gonioscopic view of the angle, which precludes goniotomy.

until they were a week or so of age to reduce anesthetic risk. With current anesthetic techniques, surgery can be safely performed on the second or third day of life. We feel that early surgery has salvaged more eyes than with delayed surgery.

Corneal diameter

Some authors have had the impression that corneal enlargement was a poor prognostic factor in trabeculotomy.25 However, this has not been the experience of Luntz and Livingston in a prospective study of 86 treated eyes.23,26 Quigley27 reported a success rate of 67% in eyes with corneal diameter greater than 14 mm compared to 100% success in eyes less than 14 mm. However, McPherson and McFarland28 noted that corneal diameter had little effect on the final outcome of the external trabeculotomy.

The success of goniotomy is decreased in eyes with significant buphthalmos (Fig. 8.4). Barkan29 felt that eyes with corneal diameters greater that 15 mm were not suitable for goniotomy. Similarly, Robertson30 reported 13 of 15 successes in non-buphthalmic eyes compared with only 3 of 10

Corneal clarity

In situations where corneal clouding prevents adequate visualization of the trabecular meshwork by gonioscopy, trabeculotomy ab externo has to be performed in children with developmental glaucoma as the initial surgical procedure (Fig. 8.3).23,24

Severity of glaucoma

In advanced cases of developmental glaucomas, initial goniotomy or trabeculotomy may be tried, but has a high failure rate. In this situation, combined trabeculotomy and trabeculectomy may offer a higher success rate than goniotomy or trabeculotomy. If the initial surgical procedure fails, it may be necessary to perform trabeculectomy with an adjunctive antifibrosis drug or glaucoma drainage implant.

Patients who appeared at birth with bilateral cloudy corneas and severe glaucoma often had surgery delayed

Figure 8.4 Buphthalmos in a child with bilateral congenital glaucoma. Severe corneal enlargement and buphthalmos is associated with decreased success of goniotomy and may be associated with increased risk of surgical complications.

successes in buphthalmic eyes. In patients with a significant increase in corneal diameter, goniotomy is technically difficult to perform and the initial procedure of choice should be trabeculotomy or ab externo combined trabeculotomy and trabeculectomy.

Our impression has been that complications may occur with increased frequency in eyes with severe corneal enlargement and buphthalmos. Additional precautions to avoid complications improve safety during the postoperative period. These precautions include tightly sutured trabeculectomy flap and two stage glaucoma drainage device implantation, in order to minimize postoperative hypotony.

Conclusion

Surgical therapy is the most effective and definitive form of treatment for the developmental glaucomas. The choice of surgical therapy is influenced by a variety of factors, including the structural defect, age of the patient, corneal clarity, and associated systemic syndromes. Consideration of these factors may guide the clinician toward more effective treatment strategies.

References

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