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Joao Victor Veloso Goncalves Godinho, Fábio Ursulino Reis Carvalho, Ricardo Holzchuh, Richard Y Hida, Fernando Cesar Abib; Reproductibility of a non-contact specular microscope in normal eyes using automatic counting. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1462.
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© ARVO (1962-2015); The Authors (2016-present)
Reproductibility of ophthalmic equipment is of great importance in way that it allows objective follow-up of patients on various aspects. Some equipment such as Optical Coherence Tomographer and Scheimpflug-Placido Tomographer have already been tested for reproducibility. The aim of this study is to evaluate non-contact (NC) SM in capturing and analyzing images from the central corneal area.
Same examiner performed specular microscopy in both eyes of 40 randomly chosen patients in the outpatient clinic. The evaluation was performed three consecutive times in each eye using NC SM CEM-350 (NIDEK©).None of the patients had any eye disease or previous ocular surgery. Patients were repositioned by being asked to stand up and sit down between each one of the three examinations. The central endothelial image was obtained in each examination and selected for analysis. The manufacturer’s software automatically counted cells and calculated parameters. The reproducibility of this sequential examination was evaluated by comparing the data calculated by the software: counted cells (CC), endothelial cell density (ECD), average cell area (AVG), coefficient of variation (CV), hexagonality percentage (HEX) and pachymetry. Data generated by manual evaluation of the cell imaging errors were also analyzed: number of non-counted EC, number of EC clusters (two or more cells counted as one), average number of cells in these clusters, number of splited EC (one cell counted as two or more), average number of EC created by these divisions and non-evaluated area of reticulum, which was calculated as 1-[counted cells x average cell area (µm2)/image size (µm2)]. Only left eyes were used for statistical analysis. Statistics were made using ANOVA for repeated measures followed by Tukey’s test for post-hoc comparisons.
Comparison of the data obtained from 3 central corneal area images in all patients has shown non-statistical difference (p>0,05). These results are presented in table 1.
NC SM CEM-350 (NIDEK©) and its software seems reproducible in capturing and analyzing the same corneal area and the same imaging errors in sequential examinations interleaved by brief moments of patient repositioning.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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