How Young is Too Young?

The challenge of congenital cataract surgery.

CLARE QUIGLEY MD REPORTS

Delivering the keynote lecture at the World Society of Paediatric Ophthalmology and Strabismus Subspecialty Day in Milan, Italy, Paolo Nucci MD, FEBO discussed congenital cataract surgery, important paradigm shifts, and his current approach.

He began with a case illustrating the impact congenital cataract surgery may have on a patient. A six-month-old child underwent a late operation for a congenital cataract. The operating surgeon implanted a multifocal lens in the sulcus. The resulting poor vision led to a referral to Prof Nucci for rehabilitation. He removed the lens implant, and the corrected vision improved from 20/400 to 20/200 with the help of occlusion therapy directed by the orthoptist. Unfortunately, the child had a severe trauma to the good eye, which was eviscerated. So, what happened to the bad eye? Following this catastrophic injury, the child’s vision unexpectedly improved, reaching 20/50.

“Maybe we know less than we believe about congenital cataract,” Prof Nucci proposed. “The first question is whether the time window for unilateral and bilateral surgery is appro- priate. Many ophthalmologists follow a strict time window of four to six weeks of age, but this could be revised later with important benefits to operated children. The problem with aphakic glaucoma is strictly related to earlier surgery. Maybe four to six weeks is a little bit early.”

He currently employs a strict patching regime to stretch surgery time, shifting the window for congenital cataract surgery to 8 to 12 weeks in unilateral and 10 to 14 weeks in bilateral.

“Keep in mind the child has interrupted waking hours and sleeps a lot,” Prof Nucci advised.

Parental monitoring, he said, is crucial, and patching should be part time, carried out for a portion of the time the infant is awake. Monitoring is harder during the neonatal stage, as waking hours are so few.

Prof Nucci suggested creating nuances for each step of congenital cataract surgery, including dilation, the main incision, and the rhexis approach. An off-label intracameral preparation that includes tropicamide, phenylephrine, and lidocaine (Mydrane®, Thea Pharmaceuticals) can dilate. He recently published how he found it provides good dilation in infants without safety concerns and is completely reversible with intracameral acetylcholine.i

In constructing incisions, Prof Nucci spares the superior cornea, carrying out cataract surgery from a temporal approach to help preserve different options for future glaucoma surgery for these patients, which one in four will go on to have.

Many surgeons can be nervous to perform capsulorhexis on infants due to the more elastic nature of the paediatric lens capsule, but Prof Nucci counselled going forward with this step.

“If you use the correct dilation and correct viscoelastic, I can say the capsulorhexis is very, very easy,” he emphasised. “Aim for a smaller capsulorhexis. Aim for a small opening in the capsule [because it] will be larger than your target. A high molecular weight viscoelastic is required. Giving care and attention to the forces at play allows a controlled manual rhexis. The movement is always centripetal.”

Regarding when to implant a lens, Prof Nucci advised between ages eighteen months and two years and using a posterior approach with a 2.5 mm to 3.0 mm port.

And what about a primary implant at a very young age? It’s a procedure he doesn’t recommend in infancy.

“The number of complications when I do this surgery under age six months is relevant. Also, there is no possibility to accurately calculate the lens.”

Prof Nucci also does not advocate for multifocal lens implantation in young children.

“We should aim for a hyperopic target. Perfect centration is quite difficult. Movement and tilt, even after months from surgery of a multifocal lens cause problems. Also, children’s eyes have unpredictable axial growth, and their reading distance is closer than that of adults,” he explained. “The one advantage, which is of course not an advantage at all, is children don’t complain. So, when problems such as glare, loss of contrast, and low vision quality arise, the ophthalmologist may not hear about it.”