PAEDIATRIC CATARACTS

Alina Bakunowicz-Åazarczyk MD

Paediatric cataracts present the ophthalmic surgeon with many compromises and dilemmas, but evidence has accumulated over the years that support certain strategies in the treatment of such eyes, said Alina Bakunowicz-Åazarczyk MD, at a symposium of the Polish Society of Cataract and Refractive Surgery at the 17th ESCRS Winter Meeting. “There are questions surrounding anterior and posterior capsule management and there are questions around when we should perform anterior vitrectomy and laser capsulotomy and which intraocular lens we should use, the type of lens and the power of the lens,” said Dr Bakunowicz-Åazarczyk, Medical University of Bialystok, Bialystok, Poland.

In congenital cataracts there is also the important question of when to operate, she noted. Operating too late will result in a lifetime of poor visual acuity, operating too early will increase the risk of glaucoma. There is a loss of one line of eventual visual acuity for every three weeks of the first 14 weeks of life outside the womb that a child’s congenital cataract is left in the eye. Operating within the first month of life reduces the likelihood of strabismus and will also preserve an eventual extra Snellen line of vision, but there is a greater risk of glaucoma and secondary membrane development. Conversely, children who undergo surgery when they are between 14 and 31 weeks of age will have a lower risk of glaucoma, but will have an unrecoverable loss of eventual vision, Dr Bakunowicz-Åazarczyk said.

Diathermic capsulorhexis,
Courtesy of Alina Bakunowicz-Åazarczyk MD

Paediatric eyes have several anatomical features that can make the removal of a cataract very difficult. To begin with they are very small and have small lenses. In addition, their elastic and thick anterior capsules require the application of more force to create the initial tear when performing a capsulorhexis. For that reason, a procedure using a vitrector, called vitrectorhexis, may be useful. Another alternative is endodiathermy. In addition, children’s pupils can be difficult to dilate and may require the use of retractor hooks and rings. Furthermore, their thin and elastic sclera makes it hard to create a self-sealing incision and generally a 10-0 nylon suture is therefore necessary.

To prevent posterior capsular opacification (PCO), Dr Bakunowicz-Åazarczyk recommended performing a posterior capsulorhexis plus vitrectomy in patients less than three years of age and posterior capsulorhexis only in patients three-tosix years of age. In patients more than six to seven years of age the posterior capsule should be left intact. If PCO occurs, a YAG Laser capsulotomy is usually sufficient although anterior vitrectomy may be necessary in some cases where the visual axis becomes opacified. Intraocular lenses (IOLs) are usually implanted in patients greater than two years of age because at one year of age there is a shift in refraction of 10 D, she said. However, some have reported acceptable results in children as young as seven days old.

She added that single-piece hydrophobic acrylic IOLs seem to be the best implants to use because they have a lower risk of PCO and secondary glaucoma. There have also been good reports with iris-fixated IOLs. Hydrophilic acrylic IOLs, on the other hand, are prone to calcium phosphate deposits and silicone contamination on the IOL surface.