Patterned Synthesis of ZnO Nanorod Arrays for Nanoplasmonic Waveguide Applications.

We report the patterned synthesis of ZnO nanorod arrays of diameters between 50 nm and 130 nm and various spacings. This was achieved by patterning hole arrays in a polymethyl methacrylate layer with electron beam lithography, followed by chemical synthesis of ZnO nanorods in the patterned holes using the hydrothermal method. The fabrication of ZnO nanorod waveguide arrays is also demonstrated by embedding the nanorods in a silver film using the electroplating process. Optical transmission measurement through the nanorod waveguide arrays is performed and strong resonant transmission of visible light is observed. We have found the resonance shifts to a longer wavelength with increasing nanorod diameter. Furthermore, the resonance wavelength is independent of the nanowaveguide array period, indicating the observed resonant transmission is the effect of a single ZnO nanorod waveguide. These nanorod waveguides may be used in single-molecule imaging and sensing as a result of the nanoscopic profile of the light transmitted through the nanorods and the controlled locations of these nanoscale light sources.

Refractive outcomes of phacoemulsification after pars plana vitrectomy using traditional and new intraocular lens calculation formulas.

PURPOSE: To evaluate refractive outcomes of cataract surgery in previously vitrectomized eyes and compare the accuracy of intraocular lens (IOL) calculation formulas in this population. SETTING: Stony Brook University Hospital, Stony Brook, New York, USA. DESIGN: Retrospective case series. METHODS: All electronic medical records of patients who had phacoemulsification from 2013 to 2017 were reviewed. Patients who had previously had pars plana vitrectomy in the same eye were selected. Patients with a history of refractive surgery, silicone oil in the eye, or other factors preventing accurate IOL power calculation were excluded. RESULTS: The mean postoperative spherical equivalent was -0.16 diopter (D) ± 0.81 (SD) (n = 61). The mean prediction errors were 0.30 ± 0.82 D, -0.09 ± 0.76 D, 0.23 ± 0.76 D, 0.25 ± 0.81 D, 0.04 ± 0.85 D, 0.30 ± 0.82 D, 0.33 ± 0.79 D, and 0.45 ± 0.80 D with the Holladay 1, Wang/Koch (WKA) adjusted Holladay 1 (n = 14), Holladay 2 (n = 48), SRK/T, WKA SRK/T (n = 14), Hill-Radial Basis Function (n = 50), and Ladas formulas, respectively. The formula with the highest percentage of predictions within ±0.50 D of the postoperative outcome was the Holladay 2 (60.42%). Statistically significant differences between the predicted and actual refractive outcomes were found with all formulas (P < .05) except the WKA Holladay and WKA SRK/T. Intraclass correlation showed low repeatability (<0.50) for all formulas. CONCLUSIONS: Refractive outcomes after cataract extraction in vitrectomized patients can be variable and more hyperopic than the predicted outcomes using traditional and newer IOL calculation methods. Thus, predicting refractive outcomes in this population is challenging, and patients should be counseled accordingly.