Could new-generation lenses be considered for children with congenital cataracts?
Click Here to Manage Email Alerts
Click here to read the Cover Story, "US surgeons benefit from early adoption of premium IOLs by European colleagues."
Positive experience with multifocal technologies
I have a long experience with pseudoaccommodating IOLs in pediatric patients.
Since the first 3M diffractive implants in 1989, I have used them in more than 2,100 children, and I always welcome new innovations such as trifocal and extended depth of focus (EDOF) lenses. So far, I have only implanted a small number of them (27 and 12, respectively), and my follow-up is limited, but I have been favorably impressed, particularly by trifocals. EDOF IOLs, at this stage of development, are insufficient for good reading vision, which is critically important for children.
Initially, when multifocal technologies made their debut, I was skeptical about their use in pediatric patients, and as I do for every new lens, I first tried them in adults. When I eventually decided to implant them in children, I was surprised to see how fast and well they adapted. While adults have to reset and retrain the visual brain through a slow and not always successful process, the neural plasticity of the children’s brain allows them to learn how to see through these lenses easily and naturally, with no photic phenomena and no loss of contrast sensitivity, as shown by a study we performed on 270 cases. After implantation of diffractive IOLs, they develop excellent vision at all distances, including intermediate, something we have never seen in adults. Importantly, the lens power is undercorrected to account for myopic shift, in the same way as we would do with monofocal IOLs.
When we perform cataract surgery in children, we make them as presbyopic as a 65 year old at a time when the development of near visual function is crucial. Multifocal IOLs are the only option that preserves accommodation and, therefore, the full visual function of a young eye. My long follow-up in many patients into adulthood has shown that good vision is maintained over time. Only in a few cases have I performed IOL exchange with a similar lens of a later generation. These were patients with a family history of myopia who developed high myopia in their teens.
My first choice so far has been diffractive multifocal IOLs with a +4 near add, leading to an approximate +3.25 add at the spectacle plane. In case of unilateral cataract, implantation should be performed early, within the first 12 months of life. With bilateral cataract, we can wait longer, evaluating the individual case and discussing it with the parents because compliance with postoperative visual rehabilitation is crucial.
Michele Fortunato, MD, is an ophthalmologist at Bambino Gesù Pediatric Hospital in Rome.
Axial growth may affect long-term outcomes
In children, monofocal IOLs are the implant of choice because of their superior image quality and minimal visual aberrations.
The new-generation trifocal and extended depth of focus (EDOF) lenses are remarkable, but their performance is sensitive to residual refractive error. In children, the initial IOL calculations are often less accurate, and the ongoing axial eye growth guarantees that any precision achieved initially will not remain unchanged over time. The myopic shift is most pronounced in the first decade of life, but even in the second decade, a variable amount of significant eye growth and myopic shift occurs. We studied 98 pseudophakic eyes with serial axial length measurements during the ages of 10 to 20 years. Those real pseudophakic patient data predicted a median axial growth from 23.11 mm at age 10 to 24.41 mm at age 20, a 4 D change in the IOL power needed for emmetropia.
Toric IOLs are a good option for children older than age 5 years because keratometry becomes stable at that age. However, trifocal and EDOF lenses should be used with caution in children who are still growing. The added cost is not a good investment for the family because spectacle independence is often short lived. In addition, monofocal IOLs perform well in children. Young patients are often happy even when they develop mild to moderate myopia over time. Ironically, the child with a trifocal or EDOF IOL may become more spectacle dependent when myopia invariably develops than the myopic child with a monofocal IOL who functions well even without glasses. Refractive surgery or IOL exchange to treat the myopia is often not offered until growth is complete.
The newer monofocal “plus” lenses such as the Tecnis Eyhance (Johnson & Johnson Vision) or the enVista (Bausch + Lomb) are much more suited for children. They have an enhanced intermediate range of focus, and they still function well when the child becomes myopic over time due to axial eye growth. Also, there is not an upcharge for these IOLs. Because we cannot promise spectacle impendence for the child, many young families are understandably reluctant to pay extra for a lens that produces multiple simultaneous images and reduces contrast sensitivity.
- Reference:
- Wilson ME, et al. Trans Am Ophthalmol Soc. 2009;107:120-124.
M. Edward Wilson, MD, is an OSN Pediatrics/Strabismus Board Member.
Collapse
Read more about
Click Here to Manage Email Alerts