How PCG subtypes are clues for surgical approach

TAKE-HOME

Primary congenital glaucoma represents four clinical subtypes that vary in age of presentation, presenting features, and angle anomaly.

By Cheryl Guttman Krader; Reviewed by David S. Walton, MD

Boston-When treating the most common childhood glaucoma, it is important for clinicians to recognize that the therapy of choice varies by the clinical subtype of the disease.

David S. Walton, MD, explained that primary congenital glaucoma (PCG), which is a hereditary disorder, is subdivided into four clinical subtypes: newborn, infantile, late-recognized, and spontaneous resolution PCG.

“The subtypes of PCG are defined by the age of the child when the glaucoma is recognized, and the presenting signs and symptoms of each is determined by the associated anomalies and severity of the IOP elevation,” said Dr. Walton, clinical professor of ophthalmology, Harvard Medical School, Boston.

Surgery is the treatment of choice for all PCG, but the approach is dictated by the angle anomaly so that careful preoperative gonioscopy is essential, he said.

“Goniosurgery is very successful for infantile and late-recognized PCG, but it is a poor choice for newborn PCG where the filtration angle is not adequately developed to support good results,” Dr. Walton said. “However, glaucoma drainage tube surgery can be very effective treatment for newborn PCG.”

Newborn PCG represents about 10% of all cases of PCG. It is usually recognized within the first few days of life based on striking corneal opacification that is the result of elevated IOP and corneal anomalies. These children also have a very thin iris and hypoplasia of the filtration angle with minimal exposed trabecular meshwork.

Infantile PCG, which is the largest clinical subtype of PCG, is usually diagnosed between 1 and 12 months of age. These children present with large eyes and also have corneal findings that are secondary to the increased IOP. Gonioscopy will reveal an open angle and a normal trabecular meshwork, but with variable narrowing and opacification of the ciliary body band and a minimally visible scleral spur. Gonioscopy for infantile PCG has a reported success rate that exceeds 90%, said Dr. Walton.

Late-recognized PCG includes children whose disease is diagnosed past 1 year of age. Dr. Walton noted that in his own series of 31 children with late-recognized PCG, the average age of presentation was 4.5 years. Late-recognized PCG affects males and females equally, and about half of children will have involvement of both eyes

The main presenting features of late-recognized PCG vary depending on the child’s age. Corneal enlargement is the main finding in children ages 1 to 4 years old, and they may also have some photophobia. Children diagnosed with PCG beyond 4 years of age are usually recognized because of poor visual acuity and rarely by routine tonometry. Late-recognized PCG is associated with moderate angle anomalies.

“Interestingly, not one child in my series who was younger than 4 years of age was recognized by the presence of cornea opacification,” Dr. Walton said.

fyi

David S. Walton, MD

E: walton.blackeye@gmail.com

Dr. Walton has no financial interest in the subject matter. This article is based on Dr. Walton’s presentation during Pediatric Ophthalmology 2012 at the annual meeting of the American Academy of Ophthalmology.