Discussion

Abstract

From the scientific perspective, the authors describe a new intraocular lens that theoretically can create spectacle-free distance and reading vision by ciliary body, vitreous-induced movement of the intraocular lens, resulting in pseudoaccommodation. This form of correction is advantageous over other alternatives such as multifocal intraocular lenses (IOLs) or monovision IOLs, because this pseudoaccommodation is relatively free of the optical distortion seen with most other techniques that allow both distance and near vision. In this paper, the data indicate that of the 62 postoperative patients, 97% saw 20/30 with their distance correction in place. However, as presented, these data immediately raise several questions. We are all familiar with the fact that many patients after routine cataract and IOL surgery, even with old-fashioned, rigid lenses, seem to read amazingly well without any additional reading correction. Because this study has no internal controls, it is difficult to judge whether 97% is better than what may be seen with more traditional IOLs. In addition, classically, we evaluate postoperative reading vision at the 20/20 level. As soon as data are presented in an alternative format, that is, percent 20/30, not percent 20/20, one is forced to suspect that the 20/20 data may be less impressive. This analysis would be similar to refractive surgeons reporting results in the 20/25 to 20/30 range when they are really looking at patients with 20/20 or better potential. I would urge the authors to use the standard reference bounds to report their data so that, in time, comparisons can be made between various alternative data sets, for surely, 20/20 will eventually appear as the reference standard. Because this study did not have a control population, and to gain some perspective, I measured a few of my own postoperative cataract patients. Most of these patients have been implanted with polymethyl methacrylate lenses. (In a consecutive series of 12 patients, with their distance correction in place, 50% saw 20/30. Clearly, my testing conditions, pupil size, and so forth are probably quite different from those of the authors. But there is some question in my mind of whether, without the appropriate controls, it would be possible to establish any statistically significant or clinically meaningful differences between this “new” lens and several older lens designs.) The movement of this new lens is critical to the authors’ thesis. Different theories of accommodation discuss a decrease in ciliary body function, that is, potential lens movement, as a function of the patient’s age. The authors may want to look at the age dependence of lens movement or pseudoaccommodation as an indication of long term effectiveness or lack thereof. Finally, objective measures of lens movement are possible, using, for example, high-resolution ultrasound. These data would be quite helpful in advancing the authors’ thesis.