Comment on: Safety of phakic intraocular collamer lens implantation in 95 highly myopic special-needs children

Abstract

We discussed the study by Reynolds et al. during the ESCRS journal club on July 7, 2021.1 In this retrospective case series, the investigators presented perioperative and longer-term adverse event data from 95 special-needs children or adults with myopia who could not comply with spectacles and/or contact lenses and underwent implantation of an intraocular collamer lens (ICL). Although this study addressed an important clinical question in a challenging patient group, we would like to highlight some points of discussion that are of relevance to the interpretation of the study. The definition of adverse events as minor or major seemed somewhat controversial. For example, in this study, wound leak requiring repair was designated as major since it necessitated a return to the theater, whereas endothelial cell loss was classed as minor. Although this nomenclature may be understandable in the context of a short-term clinical study after intervention, these definitions may not lend appropriate weight to possible serious longer-term safety concerns. The endothelial cell count was only measured in 31 of 160 eyes (ie, less than 19% of the cohort). Consequently, firm conclusions about the long-term safety of ICL implantation in this patient group cannot be made. Furthermore, these eyes are likely to be unrepresentative of the cohort since they are presumably from the most cooperative individuals. A greater yield may have been possible through specular microscopy in the lateral decubitus position undertaken under general anesthesia, although we appreciate that repeated anesthesia may have an overall detrimental effect on special-needs children. In this highly heterogeneous patient group, a more detailed presentation of the data might have allowed the reader to appreciate the relationships between clinical parameters (ie age and refraction) and adverse events. For example, the mean preoperative spherical equivalent refractive error was −11 D (range: −4 to −22) and mean age was 9.3 years (range: 1.8 to 25) with some nonpediatric patients. Illustration of distribution of refractive error and age as individual datapoints would have allowed the reader to determine, for example, whether there is a relationship between preoperative refractive error or age and postoperative endothelial cell loss? Moreover, could these parameters predict the development of postoperative pupil block? Furthermore, the details of adverse events by group (age, refraction, and underlying disorder) would have been helpful. Although the authors reported that there were 95 children and 160 implanted eyes, the article states that 35 unilateral and 60 bilateral surgeries were performed, which adds up to only 155 eyes. Previous studies on the subject have shown that ICL implantation is safe in children with a low rate of adverse events.2 Many of these studies were conducted by the same study group.3,4 Nevertheless, randomized controlled studies are needed in a larger number of pediatric patients to argue that the benefits outweigh the risks as stated by the researchers in their conclusion. Specifically, the measurement of postoperative endothelial cell counts in most individuals in such cohorts are required to make meaningful statements about long-term safety.