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Types of Glaucoma

Open-Angle GlaucomaAngle-Closure GlaucomaNormal-Tension Glaucoma (NTG)Congenital GlaucomaSecondary GlaucomaPigmentary GlaucomaPseudoexfoliative GlaucomaTraumatic GlaucomaNeovascular GlaucomaIrido Corneal Endothelial Syndrome (ICE)

Congenital Or Infantile Glaucoma

Primary congenital, or infantile, glaucoma is elevated intraocular pressure with onset in the first year of life. It occurs in about 1 out of 10,000 births and results in blindness in approximately 10% of cases and reduced vision (worse than 20/50) in about half of all cases. approximately 70% of cases are bilateral.

Although diagnosis is made in only 25% of affected infants at birth, disease onset occurswithin the first year of life in more than 80% of cases.Pediatric glaucomasConstitute a heterogeneous group of diseases that may result from an intrinsic disease or structural abnormality of the aqueous outflow pathways (primary glaucoma)Or from abnormalities affecting other regions of the eye (secondary glaucoma).A variety of systemic abnormalities are also associated with pediatric glaucoma.Systemic diseases with Glaucoma

Aniridia Marfan's syndrome Sturge-Weber syndrome Neurofibromatosis Down's syndrome Steroid therapy, including inhaled steroids for asthma and nasal steroids for allergies .

causes

Genetic (e.g. congenital glaucoma, infantile glaucoma, juvenile glaucoma) Following cataract surgery (aphakic glaucoma) Due to ocular inflammation (iritis) Trauma Malformations of the eye (Axenfeld-Rieger, aniridia , Peters anomaly) Diseases which affect the rest of the body (Sturge-Weber Syndrome, Lowe Syndrome, congenital rubella)

Aniridia

Axenfeld anomaly

Peters anomaly

Primary congenital glaucoma typically presents in the neonatal or infantile period with the classic triad of epiphora, photophobia, and blepharospasm. Corneal clouding from microcystic edema can occur, accompanied by gradual enlargement of the corneal diameter. As the edema extends through the corneal stroma, breaks called Haab striae can occur in Descemets membrane. Congenital Glaucoma (Primary Congenital Glaucoma)

Clinical Findings

Progressive corneal edema with breaks in Descemets membrane (Haab striae) Elevated IOP, typically non-sedated between 30 and 40 mmHg Corneal enlargementThe normal intraocular pressure is lower in infants and young children than adults. A newborn has an average intraocular pressure of 10-12 mm Hg, increasing to 14 mm Hg by age 7 or 8 years of age. An asymmetric measurement or an elevated measurement in the presence of other clinical signs helps make the diagnosis of glaucoma.

General Pathology

Primary congenital glaucoma may represent an arrest of the normal development of the anterior chamber. The iris and ciliary body have an anterior insertion with an open angle. The trabecular meshwork is present and appears patent, but the trabecular beams are thickened and the deeper tissues appear compressed.

The disease is more common in males, typically is bilateral, and does not have a racial or geographic preference. Most cases are sporadic, but there is an autosomal recessive(AR) inheritance pattern either autosomal dominant (AD) for some cases. (GLC3A locus on chromosome 2p21).

Risk Factors The only known risk factors are genetic consanguinity and affected siblings. The risk of congenital glaucoma in the second child is approximately 5%, and the risk increases to 25% with two affected siblings.

Diagnosis

The diagnosis of primary congenital glaucoma can often be made clinically, even without an accurate measurement of intraocular pressure. The hallmark of the disease, however, is an elevated intraocular pressure in the absence of other conditions that can cause glaucoma, such as Axenfeld-Reiger syndrome or aphakia.

. A newborns cornea is typically 9.5-10.5 mm in diameter and increases to 10.0-11.5 mm by age 1. Any diameter above 12.5 mm suggests an abnormality, especially if there is asymmetry between the two eyes.

Differential diagnosis

The differential diagnosis depends on the major presenting symptom. For the classic triad of epiphora, photophobia, and blepharospasm, the differential diagnosis includes: nasolacrimal duct obstruction conjunctivitis corneal abrasion and uveitis.

For corneal clouding and edema, the differential diagnosis includes :congenital corneal dystrophies birth trauma with tears in Descemets membrane keratitiscongenital ocular anomalies like sclerocornea or Peters anomaly or storage disesases like mucopolysaccharidoses or cystinosisFor corneal enlargement, the differential diagnosis includes :high axial myopia and megalocornea. For optic nerve cupping the differential diagnosis includes: physiologic cupping optic nerve coloboma optic nerve atrophyoptic nerve hypoplasia an optic nerve malformationPrognosis

Glaucoma that presents from 3-12 months of age has a favorable prognosis, with 80-90% of cases achieving good control of intraocular pressure with angle surgery. The vision loss in children is multifactorial and does not depend exclusively on the health of the optic nerve.

Affected children can develop significant myopia from axial elongation of the globe, astigmatism from unequal enlargement of the cornea, corneal scarringEven dislocation of the lens from excessive anterior segment enlargement. Correction of the refractive error and aggressive treatment of associated amblyopia and/or strabismus is required to maximize visual outcome.

Visual acuity is worse than 20/50 in at least 50% of cases. This condition is bilateral in about two-thirds of patientsoccurs more frequently in males (65%) than in females (35%).PathophysiologyThe basic pathologic defect in PCG remains controversial. Barkan originally proposed a Thin, imperforate membrane that covered the anterior chamber angle and blocked aqueous outflow.

By age 1 year, normal corneal diameter is 10-11.5 mm a diameter greater than 12.5 mm suggests abnormality. Glaucoma should be suspected in any child with a corneal diameter greater than 13 mm.

Medical therapy

Medical therapy for primary congenital glaucoma is typically used as an adjunct to surgery. Oral carbonic anhydrase inhibitors include acetazolamide (Diamox 10-20 mg/kg/day divided into 3 or 4 doses) and methazolamide (Neptazane 5-10 mg/kg QID). Side affects include weight loss, lethargy, and metabolic acidosis. Topical carbonic anhydrase inhibitors include dorzolamide 2% (Trusopt) and brinzolamde 1% (Azopt) drops TID. These medications may produce less reduction in intraocular pressure than oral carbonic anhydrase inhibitors, but also appear to have fewer systemic side affects. Beta-blockers (timolol or equivalent) can also be given topically, usually using a lower starting concentration of 0.25% drops BID. Side affects include:respiratory distress, caused by apnea or bronchospasm, and bradycardia.

A combined beta-blocker/carbonic anhydrase inhibitor (Cosopt) drop BID has been shown to be effective in reducing intraocular pressure in children requiring more than one topical medication. Prostaglandin analogs latanoprost 0.005% (Xalatan), travoprost 0.004% (Travatan), and bimatoprost 0.03% (Lumigan) have been effective in reducing intraocular pressure, although use is discouraged in the presence of inflammatory condition

Miotic agents (pilocarpine, echothiophate) and adrenergic agents (epinephrine, dipivefrin) are not usually effective. The alpha2-adrenergic agonist brimonidine (Alphagan) is contraindicated in children under age 2 because of potentially serious lethargy, hypotonia, hypothermia, and CNS depression.

Medical follow up

Primary congenital glaucoma requires lifelong serial measurements of intraocular pressure, corneal diameter, refractive error, and optic nerve cupping. Any change in medical regimen should be followed in 1-2 weeks to assess the efficacy of the new treatment regimen.

Surgical follow up

In the short term, these patients require frequent follow up to monitor for infection or excessive inflammation. Long term, just like patients on medical therapy, these patients require serial measurements of intraocular pressure, corneal diameter, refractive error, and optic nerve cupping. If an adequate assessment of the clinical response is not possible in the outpatient clinic, an examination under anesthesia can be performed.

Complications

The most common complication after surgery is poor control of intraocular pressure. The success rate for angle surgery is approximately 80% after 1 or 2 procedures, while the other procedures report a success rate of 33-80%.

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