We thank Portaliou and Pallikaris for showing interest in our article “Accuracy of Intraocular Lens Power Calculation Formulae in Children Less than Two Years.” We agree that is there is a myopic shift after cataract surgery in children that can be unpredictable as well. They have suggested the use of modern adjustable lenses for dealing with the problem of myopic shift. Although we were dealing with prediction error, and myopic shift was not the focus of our study, we would like to highlight a few concerns regarding the use of adjustable lenses for pediatric patients.

As highlighted by the authors themselves, multiple-component intraocular lenses (IOLs) have been tried in a few human adults with a limited follow-up. Hence, the usefulness of this technique will require validation in a greater number of human adults before contemplating such attempts in children. Another concern is the reported range of correction that is possible with this design, which is approximately 2 diopters; however, refractive surprises can range much higher, even up to 9 diopters. In addition, this adjustment requires a minimally invasive procedure, which may carry its own set of complications.

The adjustable IOL, although of various possible designs, works on 1 of the 2 basic principles: actual change of refractive power of the IOL such as in a light-adjustable lens and changing the position of the optic of the IOL with respect to the point of focus, which uses a screw- or piston-based system. Both of these IOLs are still far from perfect for use in children.

The light-adjusted IOLs are made up of silicone matrix and require the adjustment of the IOL power using ultraviolet light. This is followed by a lock-in procedure after which the power of the lens cannot be changed. This noninvasive procedure requires patient cooperation, which is difficult in young children. In addition, this IOL is made up of silicone, which is more uveogenic than a hydrophobic acrylic IOL. Further, the second adjustable IOL, as described by Jahn and Schopfer, is a polymethyl methacrylate IOL that can be adjusted using 2 small paracentesis incisions. In addition, the polymethyl methacrylate IOL optic may become displaced posteriorly. Although the use of light-adjusted IOLs theoretically sounds promising, it remains to be seen whether this is actually feasible in children where the anterior capsular rim may become fibrosed.

Hence, we conclude by saying that these adjustable lenses may need to undergo further advances and experimentation before use as an answer to the prediction error surprises, especially in children younger than 2 years. Until then, we need to focus on biometry refinements to achieve a low prediction error.

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Jan 9, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Reply
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