Rebound tonometry is a disruptive technology for checking IOP in children. It has tremendous penetration in pediatric ophthalmology practices around the world, notes Scott R. Lambert, MD. The device bounces a small, lightweight disposable probe off the cornea.
Value as screening instrument
The AAO technology assessment group assessed the outcomes of four pediatric studies. The group found that rebound tonometry tended to measure 2–3 mm Hg higher than Goldman applanation tonometry. Differences between the two techniques were greater at higher pressures.
“Rebound tonometry is a great screening tool,” Dr. Lambert said.
“If you get a high pressure from rebound tonometry, you need to follow up with some other test. But if the pressure is normal, you can be pretty confident that the child’s IOP is okay and no other testing is needed. The group also noted that rebound tonometry is better tolerated than applanation tonometry in young children.
Cost is also considerably lower for rebound tonometry. Each rebound tonometry measurement costs a few dollars versus a few thousand dollars for each an exam-under-general anesthesia.
Ophthalmologists were reluctant to subject children to an exam-under-anesthesia unless an IOP reading was absolutely necessary even before the recognition that extended or repeated general anesthesia may affect the developing brain.
Hospitalization was traumatizing to child and family as well as expensive. As a result, a small subset of children with known glaucoma or other IOP abnormality were subjected to general anesthesia 20 to 30 times during childhood.
And most children never had their IOP measured. It has long been recognized that many children will develop glaucoma following cataract surgery, Dr. Lambert noted, but the pathogenesis of glaucoma in this population has been largely unknown because IOP was rarely measured after pediatric glaucoma surgery.
“In many cases, glaucoma following congenital cataract surgery was reported to develop at older ages,” he explained, “but I think that was because they just didn’t have the ability to check IOP easily and regularly while they were young.
Rebound tonometry is giving us more information about the natural history of glaucoma following pediatric cataract surgery because we can now check IOP throughout childhood. It is helping us to understand the disease better and to treat at the most appropriate time rather than after they have more advanced disease.”
Scott R. Lambert, MD
Dr. Lambert did not indicate any proprietary interest related to the subject matter.