IOLs in children
Pros and cons of a controversial option in paediatric cataract surgery
Should multifocals be used in the paediatric population, and if so, how should they be used? This question formed the basis for a spirited debate during the World Congress of Paediatric Ophthalmology and Strabismus 2017 in Hyderabad, India.
Proponents of the use of multifocal IOLs in children suggest the lenses should counter the loss of accommodation following cataract surgery. Cyres Mehta MD, International Eye Centre, Mumbai, spoke in favour of multifocals, arguing that it was important to give depth perception to the growing visual system considering that the visual apparatus developed rapidly up to the age of eight months.
Quoting Rychwalski’s article in the Journal of Cataract and Refractive Surgery (2010), Dr Mehta stated that loss of accommodation had a greater effect on visual function and development in the paediatric age group, and since the visual world of little children was limited to their arm’s length, clear vision was required for near and distance to avoid amblyopia and disruption of binocular single vision. He also cited various studies that showed improvement in stereopsis and spectacle independence following multifocal IOLs.
Multifocal implantation in children younger than two years is controversial, and he admitted that he was perhaps in the minority of cataract surgeons comfortable with implanting a multifocal IOL in an infant. In his experience, similar benefits as in an adult were achieved, the most important being “relative” spectacle independence. He also expanded upon the concept of piggybacking by placing in the bag, a hydrophobic multifocal IOL of estimated power at the age of 15 years, followed by a HEMA piggyback IOL in the sulcus for the residual refractive error. The piggyback IOL is then explanted when the power difference reaches 4 dioptres. Thin nature, non-reactivity and ease of explantability were reasons he preferred HEMA IOLs for piggybacking. He concluded that multifocality is not an option but a necessity and is best achieved by using multiple IOLs with phased removal.
Asimina Mataftsi MD, Aristotle University of Thessaloniki, Greece, on the other hand opposed the use of multifocals in children, stating that advantages these offer in adults need not necessarily translate into the paediatric age group. Multifocals need precise biometry, excellent centration, pupil size <2.5mm and astigmatism <0.5D. Inflammation after paediatric cataract surgery is high, especially in infants, and the previously mentioned conditions are generally not satisfied in this age group.
Questions that also still need to be resolved include whether the child will be able to select the image to focus on as well as adults with multifocal IOLs do, and whether photic phenomena will hinder developing vision. It is also important to know the effect of multifocality on motion and depth perception, and whether refractive or diffractive optics are better.
Other crucial questions that need answering before large-scale adoption of multifocal IOLs in the paediatric age group, especially in unilateral cataracts, are how the multifocal will be able to compete with the contralateral normal eye. Low-contrast images secondary to multifocality affect vision more than a blurry image would do, and this can contribute to amblyopia development rather than protect against it. Posterior capsular opacification can be prolific in children, and its effect on vision through multifocal optics is important to know, as is the degree of posterior capsular opacification acceptable before significant disruption of vision occurs.
Dr Mataftsi also cautioned that considering that there is a significant level of explantation of multifocal IOLs even among adults because of patient dissatisfaction, it is important to note that the infant or toddler is simply unable to complain about any problems. Even older children are less likely than adults to complain about poor quality of vision.
Other yet unresolved issues regarding whether overcorrection is required to compensate for myopic shift will also need to be resolved. She contended that unless a child is physically incapable of wearing spectacles or contact lenses, multifocal IOLs are not an advantage.
Ken Nischal MD, Chief of Paediatric Ophthalmology, University of Pittsburgh Eye Centre, commented during a panel discussion that historically, paediatric ophthalmologists have generally lagged behind adult cataract surgeons in the acceptance of new/changed practice patterns, and that the first ophthalmologists to implant IOLs in children were actually adult cataract surgeons. Therefore, before rejecting multifocal IOLs in children, pros and cons should be weighed with an open mind.
Cyres Mehta: firstname.lastname@example.org
Asimina Mataftsi: email@example.com