Overview
Definition:
Congenital glaucoma is a rare, severe, and often inherited disorder characterized by elevated intraocular pressure (IOP) that causes progressive damage to the optic nerve and visual field loss in infants
It is typically diagnosed within the first year of life and presents with characteristic signs of tearing (epiphora) and photophobia.
Epidemiology:
The incidence of primary congenital glaucoma (PCG) varies geographically, ranging from 1 in 10,000 to 1 in 30,000 live births
It affects males slightly more than females
Approximately 60% of cases are bilateral
It can occur as an isolated condition (primary congenital glaucoma) or as part of a syndrome.
Clinical Significance:
Prompt diagnosis and management of congenital glaucoma are crucial to prevent irreversible vision loss
Untreated congenital glaucoma can lead to severe optic nerve damage, amblyopia, and blindness, significantly impacting a child's development and quality of life
Understanding its presentation is vital for pediatricians and ophthalmologists.
Clinical Presentation
Symptoms:
Excessive tearing (epiphora) in the affected eye(s)
Increased sensitivity to light (photophobia), leading to involuntary eyelid closure (blepharospasm)
Rubbing or pawing at the eyes
Watery eyes
Sometimes, a large, cloudy cornea (corneal edema).
Signs:
Enlargement of the eyeball (buphthalmos) due to elevated IOP
Corneal edema causing haziness and reduced visual acuity
Stretching and pallor of the optic disc
Increased axial length of the globe
Fundus examination may reveal optic disc cupping, which can be difficult to assess in infants.
Diagnostic Criteria:
Diagnosis is primarily based on the presence of characteristic clinical signs in an infant
Key indicators include elevated IOP (>21 mmHg), corneal edema, Haab's striae (breaks in Descemet's membrane), optic nerve cupping, and ocular enlargement
The triad of epiphora, photophobia, and blepharospasm is highly suggestive.
Diagnostic Approach
History Taking:
A detailed birth history, including any signs of prematurity or distress
Family history of glaucoma or similar eye conditions
Parental observation of excessive tearing, light sensitivity, or rubbing of eyes
Any history of trauma or infection to the eyes.
Physical Examination:
A thorough ophthalmological examination under anesthesia is often necessary for accurate assessment in infants
This includes measuring intraocular pressure (IOP) using a tonometer (e.g., Tono-Pen or Perkins applanation tonometer)
Slit-lamp examination to assess the anterior chamber, cornea (for edema and Haab's striae), iris, and lens
Fundus examination to evaluate the optic nerve head for cupping and pallor
Measurement of corneal diameter and axial length.
Investigations:
Intraocular pressure (IOP) measurement: Normal IOP in infants is typically between 10-20 mmHg
Corneal diameter measurement: A corneal diameter >11 mm in infants may be indicative of glaucoma
Ultrasound biomicroscopy (UBM) can assess anterior segment structures
Optical coherence tomography (OCT) can help evaluate optic nerve head structure and nerve fiber layer thickness
Genetic testing may be considered in suspected syndromic cases.
Differential Diagnosis:
Infectious keratitis (e.g., bacterial or viral conjunctivitis with corneal involvement)
Congenital corneal opacities (e.g., Peter's anomaly)
Congenital nasolacrimal duct obstruction (dacryostenosis) presenting with tearing, but typically without photophobia or elevated IOP
Uveitis
Traumatic eye injuries.
Management
Initial Management:
Immediate control of elevated IOP is paramount
Medical management is typically initiated to reduce IOP before surgical intervention
If IOP is very high and corneal edema is severe, a temporary patch or bandage contact lens may be used to protect the cornea.
Medical Management:
Topical beta-blockers (e.g., Timolol 0.5% - 1 drop twice daily, cautiously in infants due to systemic absorption risks)
Topical carbonic anhydrase inhibitors (e.g., Dorzolamide 2% - 1 drop twice daily)
Topical alpha-agonists (e.g., Brimonidine 0.2% - 1 drop twice daily, use with caution in infants <2 years due to CNS depression risk)
Topical miotics (e.g., Pilocarpine 1-2%) are generally avoided in congenital glaucoma due to potential for ciliary spasm and anterior segment ischemia.
Surgical Management:
Goniotomy or trabeculotomy are the primary surgical procedures for congenital glaucoma, aiming to bypass or open the trabecular meshwork to improve aqueous outflow
These are typically performed by a pediatric ophthalmologist
If medical and initial surgical management fail, a trabeculectomy or glaucoma drainage device implantation may be considered
Repeated surgeries may be necessary.
Supportive Care:
Regular monitoring of IOP, corneal clarity, optic nerve status, and visual acuity
Management of amblyopia through patching or atropine cycloplegia if present
Counseling and support for parents regarding the chronic nature of the condition and long-term follow-up needs.
Complications
Early Complications:
Hyphema (blood in the anterior chamber)
Corneal dellen (stromal thinning)
Infection following surgery
IOP spikes post-operatively.
Late Complications:
Progressive optic nerve damage and visual field loss despite treatment
Development of amblyopia
Ptosis
Strabismus
Cataract formation
Myopia progression
Recurrence of glaucoma
Scarring and visual impairment from corneal edema.
Prevention Strategies:
Early detection and prompt intervention are key
Regular ophthalmic screening of infants, especially those with risk factors
Adherence to prescribed medical and surgical management plans
Careful monitoring for signs of disease progression or recurrence.
Prognosis
Factors Affecting Prognosis:
The degree of optic nerve damage at presentation
The success of initial surgical intervention
The presence of associated ocular or systemic anomalies
Age at diagnosis and treatment initiation
Patient's adherence to follow-up and treatment.
Outcomes:
With timely and appropriate management, many children with congenital glaucoma can achieve functional vision and prevent significant vision loss
However, long-term follow-up is essential as the condition can be progressive
Complete cure is rare, and management is often lifelong.
Follow Up:
Lifelong regular ophthalmic examinations are crucial
This includes IOP monitoring, optic nerve assessment, visual acuity testing, and corneal evaluation
The frequency of follow-up will depend on the individual patient's response to treatment and disease stability.
Key Points
Exam Focus:
Recognize the classic triad of tearing, photophobia, and blepharospasm in infants
Understand the difference between primary congenital glaucoma and secondary forms
Recall the initial medical management and primary surgical options (goniotomy/trabeculotomy)
Differentiate from dacryostenosis
Be aware of complications like buphthalmos and corneal edema.
Clinical Pearls:
Always consider congenital glaucoma in an infant presenting with unexplained tearing and light sensitivity
A simple corneal diameter measurement (>11mm) can be an early clue
Intraocular pressure measurement under anesthesia is critical for definitive diagnosis
The goal is to preserve optic nerve function and prevent amblyopia.
Common Mistakes:
Attributing tearing solely to nasolacrimal duct obstruction without ruling out glaucoma
Delaying referral to an ophthalmologist
Inadequate IOP monitoring post-operatively
Underestimating the risk of amblyopia development
Using miotics routinely in congenital glaucoma.