Glaucoma, COngenital
The 5 Minute Pediatric Consult
Graham E. Quinn
DEFINITION
Congenital glaucoma is the improper development of the drainage system for aqueous humor, leading to elevated intraocular pressure with enlargement of the eye and damage to the optic nerve.
CAUSES
- Aqueous humor, a clear fluid produced by the ciliary body at the posterior base of the iris, passes through the pupil and exits through the trabecular meshwork and Schlemm’s canal, located at the junction of the cornea and the iris anteriorly.
- Blockage of outflow of the aqueous humor for any reason causes the pressure to build in the eye, resulting in enlargement of the eye in younger children and destruction of fibers of the optic nerve in children with abnormally high intraocular pressures.
PATHOPHYSIOLOGY
- Primary congenital glaucoma caused by structural abnormalities of trabecular meshwork, iris, or cornea
- Glaucoma associated with systemic abnormalities such as aniridia, rubella, Sturge-Weber
- Glaucoma acquired secondary to ocular abnormality such as cataract
EPIDEMIOLOGY/GENETICS
- 1:10,000 births
- 1:2 female to male ratio
- Seventy percent bilaterally affected
- Primary congenital glaucoma accounts for approximately one-half of all cases of glaucoma in children.
COMPLICATIONS
If glaucoma is controlled:
- Unrecognized and untreated amblyopia (the most serious threat to child’s vision)
- High degrees of myopia
- Anisometropia (difference in refractive error between fellow eyes)
- Buphthalmos and corneal scarring
PROGNOSIS
Guarded; even if pressure is well controlled, the child must be carefully followed for amblyopia, abnormal refractive errors, and recurrence of glaucoma.
ASSOCIATED DISEASES
Aniridia, Sturge-Weber, neurofibromatosis, Marfan syndrome, Pierre Robin syndrome, homocystinuria, Lowe syndrome, rubella, chromosomal abnormalities, persistent hyperplastic primary vitreous
- Excessive tearing, most commonly due to nasolacrimal duct obstruction
- Megalocornea
- May be associated with high myopia
- Often familial
- Corneal haze
- Birth trauma, forceps
- Congenital corneal dystrophies, developmental anomalies, intrauterine inflammation (rubella, syphilis), mucopolysaccharidoses, cystinosis
HISTORY
Question: Is there tearing, light sensitivity, or lid squeezing?
Significance: Epiphora (tearing), photophobia (light sensitivity), and blepharospasm (lid squeezing) may be present due to corneal edema from increased intraocular pressure.
- General signs of many systemic syndromes associated with glaucoma (neurofibromatosis, Sturge-Weber)
- Corneal enlargement (11 mm suspicious below age 1 year)
- Corneal haze from edema and/or scarring, often seen with acute ruptures in Descemet’s membrane
- Myopia, often extreme degrees
- Optic nerve cupping develops rapidly in infants but may be reversible with control of glaucoma.
INTRAOCULAR PRESSURE MEASUREMENT
- Prefer awake child; use bottle or breast to quiet along with low lighting.
- If examination under anesthesia is needed, check intraocular pressure as soon as possible after induction, because pressure drops with anesthetic agents.
CORNEAL INSPECTION
- Diameter measure with calipers
- Normal newborn, 10.0 to 10.5 mm
- Over 11.5 mm suspicious
- Watch for asymmetry.
- Clarity
- Haze may be due to edema or breaks in Descemet’s membrane (called Haab’s striae).
- Refractive error
- High myopia common
- Useful as an office measure of change over time
- Optic disc assessment
- Cupping of nerve head is an early sign.
- May reverse with good intraocular pressure control
TESTS
- Gonioscopy: evaluation of anterior chamber angle (between iris and cornea)
- In trabeculodysgenesis, the insertion of the iris into the corneoscleral angle is often flat or concave.
- Iris defects may suggest the type of abnormality causing glaucoma.
- Abnormal iris vessels may influence the surgical plan.
- Ultrasound: axial length using A-scan
- Eye usually abnormally long for age
- Longitudinal data very useful in determining continued presence of glaucoma
IMMEDIATE
- Medical treatment for glaucoma in children is usually a temporizing measure prior to surgical intervention.
- In other types of glaucoma, medical treatment involves the use of the same medications as those used in adults, such as beta-blockers, adrenergic agents, and carbonic anhydrase inhibitors. In general, miotics are not usedbecause they may cause a paradoxical rise in intraocular pressure.
SURGICAL PROCEDURES
- Goniotomy/trabeculotomy: Both of these procedures open portions of Schlemm’s canal (goniotomy approaches Schlemm’s canal from inside the eye and trabeculotomy from the outside) into the anterior chamber, allowing easier outflow of aqueous humor to the subconjunctival space.
- Trabeculectomy: This is similar to trabeculotomy but includes excision of a small portion of Schlemm’s canal and the trabecular meshwork.
- Seton procedures: Various devices are inserted from the subconjunctival space into the anterior chamber, allowing free flow of aqueous humor from the eye.
- Cyclodestructive procedures: Procedures involving destruction of the ciliary body (which produces aqueous humor) decrease aqueous production.
- Iridectomy: If the mechanism of glaucoma is limited outflow of aqueous humor from posterior to iris through the pupil, then removal of a portion of the iris may eliminate obstruction.
EARLY POSTOPERATIVE
- Postoperative steroids and cycloplegic drops are essential to prevent adhesions due to inflammation and to decrease pain.
- Corneal edema clears slowly, but intraocular pressure quickly falls if surgery is successful.
- For young infants, examination under anesthesia may be required frequently in the first 3 to 4 years of life to ensure adequate control of intraocular pressure.
- Contact with social services for blind and visually handicapped individuals must be made for children even if they are only suspected of being visually impaired. Encourage families to make the contact even when the child may be too young to provide objective data on the extent of visual handicap.
PITFALLS
- Even when pressure is well controlled and amblyopia treatment is undertaken vigorously, the child is still at high risk for visual impairment.
- The child and its family must understand that glaucoma may recur at any point and that continued, long-term surveillance is essential.
- Ensure that potential systemic medicines do not raise intraocular pressure.
| COMMON QUESTIONS AND ANSWERS |
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Q: Can glaucoma be painful?
A: If the ocular pressure rises quickly (hours), pain occurs frequently. Very high intraocular pressures may be present without pain if they occur slowly (months to years).
Q: Can glaucoma occur after eye trauma?
A: Yes. This is a very common cause of glaucoma and may be asymptomatic, thus requiring follow-up ophthalmic examinations for early detection and treatment.
ICD-9-CM 743.20
Dickens CJ, Hoskins HD. Developmental glaucoma. In: Isenberg SJ, ed. The eye in infancy. 2nd ed. Chicago: Yearbook Medical, 1994:318–335.
Quigley HA. Childhood glaucoma. Ophthalmology 1982;89:219–225.
Shields MB. Primary congenital glaucoma. In: Shields MB, ed. Textbook of glaucoma. Baltimore: Williams & Wilkins, 1992:220–234.
Copyright © 2000 Lippincott Williams & Wilkins
M. William Schwartz, Louis M. Bell, Jr., Peter M. Bingham, Esther K. Chung, David F. Friedman and Andrew E. Mulberg, The 5 Minute Pediatric Consult