We read with interest the article by Odenthal et al1 in the April 2002 issue of the ARCHIVES, and we congratulate the authors on their efforts to collect all these data. However, we would like to comment on the data published in Table 2.1(p435) We were surprised to note that in eyes that underwent intraocular lens (IOL) exchange, the power of the spectacle refraction was not consistent with the change in the power of the IOL. For example, in the left eye of patient 2 and the right eye of patient 3, the difference in power between the first and final IOL implants was inferior to the difference in spectacle refraction; on the contrary, in the left eye of patient 3 and the right eyes of patients 4 and 6, the difference in power between the first and final IOL implants was superior to the difference in spectacle refraction. Moreover, even if the power was increased by 3 diopters(D) in the right and left eyes of patient 3, in one eye there was a change of 4 D of spherical equivalence, and in the other eye the change was of 2.75 D. In our opinion, this cannot be explained by the change of the A constant because even if in the first group (the left eye of patient 2 and the right eye of patient 3) an IOL with a lower A constant was used for the second implant, in the second group (the left eye of patient 3 and the right eyes of patients 4 and 6) a lower A constant was used in 1 patient, whereas the same A constant was used in the other 2. In our opinion, the only explanations are a mistake in measuring the patient's refraction or a printing error. We believe that this point should be clarified because precise measurement of the refraction is crucial in determining the efficacy, significance, and repeatability of this kind of study.
Rosa N, Capasso L. Intraocular Lens Power Calculation After Photorefractive Keratectomy for Myopia. Arch Ophthalmol. 2003;121(4):584. doi:10.1001/archopht.121.4.584-a