Isa Mohamud

Summary

Congenital glaucoma is a rare but potentially blinding condition resulting from abnormal development of the aqueous outflow pathways, leading to elevated intraocular pressure (IOP) during infancy or early childhood (1). Although uncommon, it represents an important cause of irreversible childhood visual impairment if not diagnosed and treated promptly (2). The disorder encompasses a heterogeneous group of conditions with varying aetiologies, clinical presentations, and prognoses. This clinical overview summarises current literature on the epidemiology, pathophysiology, clinical features, diagnostic evaluation, and management of congenital glaucoma and highlights key principles relevant to clinical practice.

Introduction

Childhood glaucoma comprises a distinct group of disorders that differ fundamentally from adult-onset glaucoma in terms of aetiology, clinical manifestations, diagnostic approach, and management strategies (2). Congenital glaucoma, in particular, presents unique challenges due to the immaturity of ocular structures, rapid disease progression if untreated, and the need for examination and intervention at an early age (3).

Congenital glaucoma is estimated to occur in approximately 1 in 10,000–20,000 live births, with marked variation across geographic regions and ethnic groups (1,3). Higher incidence rates have been reported in populations with increased consanguinity, reflecting the significant genetic contribution to disease pathogenesis (5). Despite its low prevalence, congenital glaucoma accounts for a substantial proportion of childhood blindness worldwide, particularly in regions where access to specialised paediatric ophthalmic care is limited (1).

The disease typically presents within the first year of life, most commonly during the first 6 months (2). Elevated IOP during this critical period disrupts normal ocular development, resulting in characteristic anatomical changes, including corneal enlargement, globe distension, and optic nerve damage (4). Unlike the adult eye, the infantile sclera and cornea are highly distensible, allowing sustained IOP elevation to cause progressive enlargement of ocular structures, a defining feature of congenital glaucoma (2).

Early diagnosis is crucial, as timely intervention can halt disease progression and preserve useful vision (7). However, diagnosis may be delayed due to nonspecific early symptoms, limited awareness among caregivers, and challenges associated with paediatric eye examination. The frequent requirement for examination under anaesthesia (EUA) further complicates both diagnosis and long-term monitoring (2).

Management of congenital glaucoma differs significantly from adult glaucoma, as surgical intervention is the cornerstone of treatment, while medical therapy serves only an adjunctive role (4). Advances in surgical techniques have improved long-term outcomes, though lifelong follow-up is essential to monitor IOP control, visual development, refractive errors, and amblyopia (6).

Pathophysiology and Aetiology

Congenital glaucoma is broadly classified into primary and secondary forms (2).

Primary congenital glaucoma (PCG)

PCG occurs in isolation, without associated ocular or systemic abnormalities. The underlying pathology is abnormal development of the trabecular meshwork and anterior chamber angle, collectively referred to as trabeculodysgenesis (2,4). This structural abnormality impairs aqueous humour outflow, leading to elevated IOP and subsequent optic nerve damage.

Genetic factors play a major role in PCG. Mutations in the CYP1B1 gene are most frequently identified, particularly in populations with high rates of consanguinity (5). Other genes, including LTBP2 and TEK, have also been implicated, supporting the concept of genetically mediated anterior segment dysgenesis (5).

Secondary congenital glaucoma

Secondary congenital glaucoma occurs in association with other ocular or systemic conditions such as aniridia, Axenfeld–Rieger syndrome, Peters anomaly, Sturge–Weber syndrome, or following paediatric cataract surgery (2,6). The mechanisms of IOP elevation vary and may include angle malformations, increased episcleral venous pressure, or postoperative disruption of aqueous outflow pathways (6).

Clinical Presentation

The clinical manifestations of congenital glaucoma reflect the effects of elevated IOP on the developing eye. The classic triad includes epiphora (excessive tears), photophobia and blepharospasm (4).

Additional signs commonly described in the literature include:

• Buphthalmos: enlargement of the eyeball resulting from distension of the sclera
• Enlarged corneal diameter, typically exceeding 12 mm in infants
• Corneal oedema and clouding, due to endothelial dysfunction
• Haab striae, representing breaks in Descemet’s membrane
• Optic disc cupping, which may be partially reversible with early treatment (2,4)

Symptoms most often present within the first 6 months of life, although later presentation may occur, particularly in milder or secondary forms of the disease (1).

Diagnostic Evaluation

Accurate diagnosis frequently requires examination under anaesthesia (EUA), as infants and young children are unable to cooperate with detailed ophthalmic examination (2).

Key components of diagnostic evaluation include:

• Measurement of intraocular pressure
• Assessment of corneal clarity and horizontal corneal diameter
• Gonioscopy to evaluate anterior chamber angle development
• Examination of the optic nerve head
• Measurement of axial length, with progressive elongation indicating inadequate IOP control (4)

Adjunctive investigations such as ultrasound biomicroscopy or anterior segment optical coherence tomography may be useful in selected cases, particularly in complex or secondary congenital glaucoma (6).

Management

The management of congenital glaucoma is primarily surgical, with medical therapy serving a supportive and temporary role (2).

Medical Therapy

Topical beta-blockers and carbonic anhydrase inhibitors are commonly used to reduce IOP preoperatively and improve corneal clarity (2). Systemic acetazolamide may be employed for short-term IOP control. Prostaglandin analogues generally demonstrate limited effectiveness in congenital glaucoma and are not considered first-line therapy (6).

Surgical Management

Surgical intervention remains the definitive treatment

• Goniotomy is preferred when the cornea is sufficiently clear to allow visualisation of the angle structures (4).
• Trabeculotomy is indicated when corneal opacity prevents adequate visualisation (2).
• Combined trabeculotomy–trabeculectomy may be required in advanced or refractory cases (7).
• Glaucoma drainage devices and cyclodestructive procedures are reserved for disease or secondary congenital glaucoma due to their higher risk profiles (6).

Early surgical intervention is consistently associated with improved long-term IOP control and better visual outcomes (7).

Prognosis and Follow-Up

The prognosis of congenital glaucoma depends on age at presentation, severity of disease, underlying aetiology, and success of surgical intervention (2). Primary congenital glaucoma diagnosed and treated early generally carries a favourable prognosis, whereas secondary forms and delayed presentation are associated with poorer outcomes (6).

Lifelong follow-up is required to monitor IOP, optic nerve status, visual development, refractive errors and amblyopia. Multidisciplinary care involving paediatric ophthalmologists, orthoptists and low-vision services is often necessary to optimise visual outcomes.

Conclusion

Congenital glaucoma is a sight-threatening paediatric condition that requires early recognition, accurate diagnosis and prompt surgical management. Understanding its pathophysiology and clinical presentation enables timely intervention, while advances in surgical techniques have improved long-term outcomes. Continued surveillance throughout childhood remains essential to preserve vision and manage associated complications (2,7).

References

1. Papadopoulos M, Cable N, Rahi J, Khaw PT. The British Infantile and Childhood Glaucoma Eye Study. Invest Ophthalmol Vis Sci. 2007;48(9):4100–6.
2. Mandal AK, Chakrabarti D. Update on congenital glaucoma. Indian J Ophthalmol. 2011;59(Suppl):S148–57.
3. Taylor RH, Ainsworth JR, Evans AR, Levin AV. The epidemiology of pediatric glaucoma. JAAPOS. 1999;3(3):154–64.
4. Shaffer RN, Weiss DI. Congenital and Pediatric Glaucomas. St Louis: Mosby; 1970.
5. Al-Hazmi A, Zwaan J, Awad A, et al. Genetic and surgical outcomes in primary congenital glaucoma. Ophthalmology. 2005;112(12):2142–9.
6. Beck AD. Diagnosis and management of pediatric glaucoma. Ophthalmol Clin North Am. 2001;14(3):501–12.
7. Mandal AK, Gothwal VK, Bagga H, et al. Outcome of surgery for primary congenital glaucoma. Ophthalmology. 2003;110(10):1919–26.