Secondary IOL implantation in infant aphakia: when and how
Daniel J. Salchow MD
The Infant Aphakia Treatment Study found that when performing cataract surgery in infants up to six months of age, it is appropriate to leave most children aphakic. Therefore, for many children the question becomes when to perform secondary IOL implantation and how to do the surgery.
Addressing these issues at the World Society of Paediatric Ophthalmology and Strabismus subspecialty day preceding the 36th Congress of the ESCRS in Vienna, Daniel J. Salchow MD noted that there is no one-size-fits-all answer.
As a guideline, he recommended that secondary IOL implantation should be done as late as possible, but the timing will depend on many factors.
“These procedures are not free of complications. I believe, however, that we are lucky to be practising at a time where we are able to help almost every aphakic child because we have different options.”
Waiting to implant a secondary IOL is advisable because it will have better refractive predictability, but earlier implantation may be necessary if the child is at risk for amblyopia because of difficulties with contact lens or spectacle wear. Although there are various formulas for predicting myopic shift over time, there is a lot of individual variability. “The younger the child, the less precise the IOL is that you can put in,” Dr Salchow said.
The adequacy of capsular support is one factor influencing IOL selection. When in-the-bag implantation is not an option, sulcus placement can be done. Then, a three-piece design is generally advised as it is more stable than a single-piece lens.
When there are intact anterior and posterior capsulotomies and the two leaflets are fused, implantation of the bag-in-the-lens may be considered. However, preparation is time-consuming as it requires separating the capsule leaflets and aspirating existing lens material and it does not always work. If in this case sulcus placement is selected, it is important to remove lens material between the capsule leaflets in order to avoid secondary-angle closure through anterior displacement of the IOL.
A recent study comparing in-the-bag and sulcus secondary IOL implantation found no difference in prediction error between the two, but the sulcus lenses tended to cause more corneal oedema and early postoperative inflammation. The rate of glaucoma was also higher in the sulcus group, although Dr Salchow suggested that this might have been the consequence of differences between the eyes rather than of the site of IOL placement because the anterior chamber angle maintains normal configuration with sulcus placement.
A study including 174 eyes with secondary IOL implantation showed good visual results, but also showed the potential for complications such as membrane formation in about 10% of eyes, optic capture, hypotony, IOL decentration, and glaucoma.
In eyes with a subluxated lens associated with Marfan syndrome or homocystinuria where placement of a capsular tension ring is not possible, Dr Salchow said he has abandoned suturing the IOL to the iris after he had two patients develop iris cysts. Since then, he and colleagues have been using the iris clip lens. A retrospective review including seven eyes of four patients, showed that the children had good visual outcomes with an acceptable endothelial cell loss rate, and no child developed glaucoma or other complications.
“This is a nice technique because it is something that can work when there is no capsular support and you want to avoid suturing an IOL,” he noted.
Daniel Salchow: firstname.lastname@example.org