Answer: Can you identify this condition?

3. Primary congenital glaucoma

Primary congenital glaucoma (PCG), also known as infantile glaucoma, is a potentially blinding ocular disorder that is usually present at birth or within the first year of life; it occurs approximately once in every 10 000 live births. However, its associated signs and symptoms can go unrecognized. The disorder is autosomal recessive or sporadic and related to abnormal development of the drainage system of the eye (trabecular meshwork and Schlemm canal). The abnormality results in elevated intraocular pressure causing damage to various ocular structures, including the optic nerve, which ultimately leads to blindness. Approximately 75% of cases are bilateral and about 66% occur in boys.¹ Early recognition and appropriate management are essential and can considerably improve the visual prognosis of these children.

In most cases it is the parents who first notice the enlargement of their child’s eyes. The eye is extremely soft and elastic in the first few years of life,² and increased intraocular pressure results in overall eye enlargement (buphthalmos or oxeye). Enlargement and clouding of the cornea are characteristic of this condition. At birth, the normal horizontal corneal diameter is 10.5 mm, and measurements greater than 12 mm are highly indicative of glaucoma.^1,3 With increasing intraocular pressure, and as the eye continues to swell, the inner layer of the cornea (ie, the Descemet membrane) breaks (which appears as Haab striae), resulting in corneal edema and haziness. This is often accompanied by redness, pain, sensitivity to light (photophobia), and excessive tearing.¹ Any baby with whitening of the cornea, enlarged eyes, or tearing requires immediate assessment by an ophthalmologist.

Differential diagnosis

The differential diagnosis for congenital glaucoma is based on the observation of a cloudy cornea and frequently tearing eye. The mnemonic STUMPED is a good aid to remember the differential diagnosis of a neonate with a cloudy cornea.^4,5

• Sclerocornea

  • -A rare disorder caused by the abnormal development of the tissues of the anterior segment of the eye. It usually occurs bilaterally, but can occur unilaterally. Patients might present with varying degrees of vascularized, peripheral, white cornea rim that merges with the sclera, eliminating the limbus. The central cornea is usually normal, whereas in Peters anomaly the central cornea is opaque.⁶

• Trauma

  • -Birth trauma (eg, forceps-induced obstetric trauma) can result in breaks in the inner layer of the cornea (Descemet membrane), leading to corneal clouding and edema. This clouding of the cornea is different from PCG owing to associated trauma to periorbital soft tissues, normal intraocular pressures, absence of corneal enlargement, and a deep anterior chamber.⁵

• Ulcers

  • -Bacterial or viral infections (eg, herpes simplex, rubella) of the cornea can cause a cloudy cornea in a newborn.

• Metabolic disorders

  • -Several lysosomal metabolic disorders and glycogen storage diseases can cause corneal clouding.

• Peters anomaly

  • -An uncommon disorder caused by abnormal development of the anterior segment of the eye, resulting in central or complete clouding of the cornea. It typically also involves the lens, causing the formation of cataracts.⁷

• Endothelial dystrophy (eg, congenital hereditary endothelial dystrophy)

  • -Congenital hereditary endothelial dystrophy is either autosomal dominant or recessive. The recessive form is usually present at birth and nonprogressive, with infants experiencing intense cornea edema. On the other hand, the dominantly inherited form is usually milder in presentation, with parents of affected infants noticing corneal haziness, tearing, and sensitivity to light.⁵

• Dermoids

  • -Limbal dermoids are benign congenital tumours that contain ectopic tissue and are most often located on the inferior temporal area of the corneal limbus. In rare instances, they present exclusively within the cornea or remain limited to the conjunctiva.⁸

Management

Urgent referral to an ophthalmologist (typically a pediatric ophthalmologist or glaucoma specialist) is warranted in any newborn with whitening of the cornea, enlarged eyes, and frequent tearing. The child will likely require a complete ocular examination under general anesthesia in the operating room to confirm both the diagnosis and that no secondary cause is present. The usual treatment for PCG is surgery.¹ Medical therapy with intraocular pressure–lowering medications is only a temporizing measure to control pressure before and after surgery.² Surgical techniques are aimed at opening the drainage system of the eye, with either an internal (goniotomy) or external (trabeculotomy) approach, so that fluid (aqueous humour) in the eye can drain properly. These surgeries are reported to be successful 80% of the time.¹ The most favourable outcome is observed in neonates between the ages of 2 and 8 months.² In older infants, surgery is found to be less effective, emphasizing the importance of early diagnosis and treatment. Children also need to be managed for refractive errors and to prevent amblyopia (lazy eye).