A. Samojedny

E. Pastuszek

J James

K. Lukaszuk

M Spencer

N Gatimel

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LETTER TO EDITORComment on: BIntracytoplasmic morphologically selected sperminjection (IMSI) does not improve outcome in patients with twosuccessive IVF-ICSI failures^ by Gatimel et al.K. Lukaszuk1,2 & E. Pastuszek1,2 & A. Samojedny1Received: 18 May 2016 /Accepted: 19 May 2016 /Published online: 30 May 2016# The Author(s) 2016. This article is published with open access at Springerlink.comDear Editor,We have read with great interest the article BIntracytoplasmicmorphologically selected sperm injection (IMSI) does not im-prove outcome in patients with two successive IVF-ICSIfailures^ by Gatimel and colleagues [1].However, we have to bring attention to the problem whichis unfortunately repeated in many articles and shows theweakness of our field in the application of basic physics.The authors state that the spermatozoa were observed under×6000 magnification. It is a very misleading claim that makesit seem that it is indeed possible to obtain such magnificationusing a standard optical microscope (even a most advancedone). Calculation of the actual real magnification is impossibleas the article does not list the basic microscope parameters—objective numeric aperture (NA), condenser NA and wave-length that was used to observe the spermatozoa [2, 3].Nevertheless, let us try to calculate the actual real magnifi-cation used by the authors. We know that the objective’s mag-nification was ×100. It is described as an immersion micro-scope so we can assume the immersion was in oil (as opposedto air). The objective was mounted on the Leica DMI 6000invertedmicroscope. Available objectives of this type have theNA from 1.3 to 1.49. Let’s assume the NA of 1.4.Resolution, and consequently the real magnification, also de-pends on the condenser. As no specific information is provided,we could deduce that, in the best case scenario, the microscopehad the condenser typically used in cell cultures and IVF labo-ratories. These kinds of condensers need to have a relatively largeworking distance that always means a lower condenser NA.A condenser allowingmoderate comfort of work that couldbe used with a ×100 objective would be TI-C-LWD LWD(numerical aperture 0.52).Wavelength is another parameter that has not been provid-ed. In order to get optimal resolution, a filer was probablyused. We can assume the use of a standard filter, i.e., a green550-nm filter. Resolution can be calculated based on the fol-lowing formula:r ¼ 1:22λNAob j: þ NAcond:In a properly configured microscope: NAobj . +NAcond. = 2NAobj.We arrive at 0.35 μm. As the resolution of the human eye isapproximately 300 dpi (dots per pixel) or 83 μm pixels on thescreen 30 cm away from the human eye, we arrive at themagnification of ×237.If we assume a much worse than usual eyesight (100 dpi)with the use of an ideal objective with NA of 1.49, T-C HighNA condenser with NA of 0.85, and a 400-nm filter (bluefilter that gives the highest resolution achievable with the hu-man eye), we will get the real resolution of 0.21 μm and realmagnification of only ×1199.We can say, simplifying it greatly, that the real magnifica-tion of a microscope can be most easily estimated by multi-plying the objective’s NA by 1000. It is a highly idealizedmodel as exemplified by above calculations.This should all be taken into account when informationabout microscopes is included in publications and when usedto rationalize data and results.* E. Pastuszekewa_pastuszek@gumed.edu.pl1 INVICTA Fertility and Reproductive Center, WroclawGdansk, Warsaw, Poland2 Department of Obstetrics and Gynecological Nursing, Faculty ofHealth Sciences Medical, University of Gdansk, Gdansk, PolandJ Assist Reprod Genet (2016) 33:1253–1254DOI 10.1007/s10815-016-0746-9Open Access This article is distributed under the terms of theCreative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricteduse, distribution, and reproduction in any medium, provided you giveappropriate credit to the original author(s) and the source, provide a linkto the Creative Commons license, and indicate if changes were made.References1. Gatimel N, Parinaud J, Leandri RD. Intracytoplasmic morphologi-cally selected sperm injection (IMSI) does not improve outcome inpatients with two successive IVF-ICSI failures. J Assist ReprodGenet. 2016;33:349–55.2. James J, Tanke HJ. Biomedical light microscopy, softcover reprint ofthe original 1st ed. 1991st ed. New York: Springer Science &Business Media; 2012.3. Spencer M. Fundamentals of light microscopy (IUPAB BiophysicsSeries). 1st ed. Cambridge: Cambridge University Press; 1982.1254 J Assist Reprod Genet (2016) 33:1253–1254

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Comment on: “Intracytoplasmic morphologically selected sperm injection (IMSI) does not improve outcome in patients with two successive IVF-ICSI failures” by Gatimel et al.

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Comment on: “Intracytoplasmic morphologically selected sperm injection (IMSI) does not improve outcome in patients with two successive IVF-ICSI failures” by Gatimel et al.

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