Erratum in: “Evaluation of Therapeutic Tissue Crosslinking (TXL) for Myopia Using Second Harmonic Generation Signal Microscopy in Rabbit Sclera” by Mariya Zyablitskaya, Anna Takaoka, Emilia L. Munteanu, Takayuki Nagasaki, Stephen L. Trokel, and David C. Paik (Invest Ophthalmol Vis Sci. 2017;58:21–29) doi: 10.1167/iovs.16-20241
In the Methods and Materials section the laser power setting for the Nikon A1R-MP laser scanning imaging system should read: “Laser power was 60 mW (2.5% of full power) at 860 nm. . . .”
We would like to provide clarification regarding the microscopy and light sourcing terminology used in this study.
The imaging system that we used (Nikon A1R-MP laser scanning system; Nikon Instruments, Melville, NY, USA) does include confocal microscopy components, including the descanned detectors and pinhole aperture. However, second harmonic generation (SHG) signals are not collected through this component of the microscope, and therefore we were not performing “confocal microscopy (CM)” in the strictest sense of the term. In SHG microscopy the total signal is collected in a different light path by high-sensitivity non-descanned detectors (NDD), which are located close to the back aperture of the objective in order to detect the maximum amount of emission signals. This SHG microscopy light path does not include a pinhole aperture (typically used in CM to exclude out-of-focus light) because the optical sectioning in SHG microscopy occurs at the level of the focal volume where the incident laser light is concentrated to a level necessary to produce SHG signal. Thus, the term “confocal microscopy (CM)” should be replaced throughout the text with “laser scanning microscopy (LSM)” in order to be precise.
Secondly, we used a tunable, pulsed, infrared laser (Chameleon Vision II; Coherent, Santa Clara, CA, USA) capable of generating both autofluorescence and SHG signals in specimens. However, the term “two-photon excitation (TPE)” is reserved for absorptive processes such as autofluorescence, which we did not include in this report, focusing solely on SHG signals. Since SHG is a nonabsorptive process, the term “two-photon excitation (TPE)” is technically incorrect. Thus, the term “two-photon excitation (TPE)” should be replaced throughout the text with “infrared laser excitation” in order to be precise.
In summary, the term “second harmonic generation signal microscopy (SHGM),” as used in the manuscript title, is a term that indicates the use of both non-descanned detectors as well as nonabsorptive laser light excitation, and is correct. However, the terms confocal microscopy (CM) and two-photon excitation (TPE) were used imprecisely throughout the text as noted above.
These corrections, as well as a few other text changes, have been made to the article online.
Citation: Zyablitskaya M, Takaoka A, Munteanu EL, Nagasaki T, Trokel SL, Paik DC. Erratum in: Evaluation of therapeutic tissue crosslinking (TXL) for myopia using second harmonic generation signal microscopy in rabbit sclera. Invest Ophthalmol Vis Sci. 2017;58:4161. DOI: 10.1167/iovs.16-20241a