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RESEARCH PRODUCT

Reliability results of straylight measurements using the C-Quant

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description

Purpose Assessment of repeatability and reproducibility of straylight measures with the C-Quant straylightmeter (Oculus AG, Germany), effect of age on reliability measures and correlation of measures determined with new methods of scatter determination. Methods Results from different studies will be presented. For repeatability assessment, 20 eyes (age 26.9±2.7 years) were examined with the C-Quant, taking 10 consecutive readings. 5 subjects were also examined on 5 consecutive days to assess reproducibility. Repeated measures from 84 subjects, age range 19-86 years, were analysed to assess the effect of patient’s age. Software was developed to quantify scatter from centroid patterns obtained using a clinical aberrometer(WASCA, Zeiss) based on previous work by Donnelly & Applegate, and 3 values were obtained on 10 eyes. 3 measures were also made with the C-Quant. Preliminary results comparing the C-Quant and the StarLight hallometer will also be presented. Results Results failed to show differences between readings taken within the same session (mean SD 0.07, p>0.05) or between sessions (mean SD 0.05, p>0.05). Variability of intrasession measurements was not significant for subjects of different age (p=0.094). After removal of incomplete patterns, good correlation was achieved between psychometric and objective measures despite small sample size (n=6; r= -0.831, p=0.040). Conclusion The C-Quant straylightmeter is repeatable and reliable for retinal straylight assessment on human eyes. Age does not decrease repeatability eventhough they feel more insecure about their ability to perform the test. Psychometrical determination of straylight showed remarkably high correlation with objective measures of scatter on young healthy subjects.