| Background and objectiveCystoid macular edema (CME) is a common fundus disease. It is not an independent idiopathic disease but results from a variety of fundus diseases. Optical coherence tomography (OCT)and fluorescence fundus angiography (FA) are the main methods of CME diagnosis at current. Fundus autofluorescence (AF) imaging is a fast and noninvasive technique developed over the last decade and became the focus in the field of fundus diseases. However,rare study about AF imaging in CME had been carried out due to macular pigment disturbing the observation of AF imaging in CME. Our purpose was to investigate the characteristics of shortwave autofluorescence(SW-AF) in CME patients and to evaluate it’s clinical application.MethodsA cross-sectional study of140cases (189eyes) was carried out. All selected eyes were suffered from primary eye disease or underwent intraocular surgery which easily lead to CME. In those189eyes,129eyes were diagnosed as CME and60eyes without CME by examination of OCT.All cases were underwent ocular examination such as SW-AF, infrared autofluorescence (IR-AF), FFA and OCT. SW-AF imagings were collected by a confocal scanning laser ophthalmoscope which uses an argon blue laser light with a wavelength of488nm for excitation and a barrier filter with a cut-off at500nm. Autofluorescence images were produced using a30°field-of-view mode with512*512pixel resolution,scanning,but without injecting contrast agent. Calculating the sensitivity, specificity and other indicators in diagnostic test of SW-AF in CME with OCT images as golden standard. Measuring the maximum ILM-RPE thickness in fovea of CME eyes either with true positive nor with false negative in SW-AF images and compare the value of two groups. Observing the relationship of relative grayscale ratio of cystoid hyper-fluorescence and maximum ILM-RPE thickness in fovea in CME eyes with positive SW-AF images and analysis of the correlation between them. Grayscale of SW-AF images was determined by Photoshop cs5.0. All statistical analysis including x2test, independent sample T test, correlation analysis and linear regression were calculate with spss13.0.Results129eyes were diagnosed as CME by OCT and displayed focal or multiple cystoid increased autofluorescence in fovea in SW-AF images,the patterns of these was perfectly corresponding with shape in their FFA images. Only29eyes (22.48%) were diagnosed as CME by IR-AF, the sensitivity were with statistically significant defferent compared with SW-AF,P<0.001(x2test). Regard OCT images as gold standard in diagosis of CME,SW-AF had certain accuracy with sensitivity78.29%, specificity96.67%, Youden index0.75,positive predictive value98.06%, negative predictive value67.44%and AUC was0.875as95%confidence interval rang0.823-0.926, P<0.001.CME eyes with true positive SW-AF images had lager maximum ILM-RPE thickness in fovea(500.36±132.62um) than those with false negative SW-AF images(316.35±79.92um), the defference was statistically significant,P<0.001(t test for independent samples).The value of relative grayscale ratio in cystoid hyper-fluorescence and maximum ILM-RPE thickness in fovea displayed linear correlation trend in scatter diagram, further more,correlation analysis showed a correlation coefficient of0.846, P<0.01,r2=0.717,and regression formula coule been delivered as Y=0.0003773X+0.633.ConlusionSW-AF can be used as a new rapid, non-invasive,ancillary technique and played a important role in diagnosis of CME. We can infer the ILM-RPE thickness in fovea by analysing the grayscale value of SW-AF images. |
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