Acta ophthalmologica · 2019
Quantification of forward scattering based on the analysis of double-pass images in the frequency domain.
СтатьяНаблюдательное исследованиеНазвание и аннотация: Перевод пока не подготовлен
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Martínez-Roda Joan A, García-Guerra Carlos E, Diaz-Doutón Fernando, Pujol Jaume, Salvador Antoni, Vilaseca Meritxell
Аннотация
PURPOSE: To assess forward intraocular scattering by means of a new parameter (Frequency Scatter Index, FSI3 ) based on the analysing double-pass retinal images in the frequency domain, which minimizes the impact of aberrations on the results.
METHODS: A prospective observational study was carried out in the Department of Ophthalmology, Hospital Universitari Mútua de Terrassa (Spain) on a group of 19 patients diagnosed with nuclear cataracts of various LOCSIII grades and a control group (CG) with nine healthy eyes. We recorded double-pass retinal images with a custom set-up based on a high-sensitivity digital camera. The FSI3 was then computed using spatial frequencies below three cycles per degree. A preliminary validation of the FSI3 was performed on an artificial eye and two eyes of volunteers with and without commercial diffusers, and under defocus.
RESULTS: The FSI3 was hardly affected by defocus values up to 2.50 D. The mean (and standard deviation) FSI3 values were as follows: for the CG, 1.19 (0.21); and for LOCSIII grades nuclear opacity 1, 2 and 3, 1.30 (0.12), 1.62 (0.21) and 1.85 (0.21), respectively. Eyes with cataracts showed FSI3 values significantly different than healthy eyes (p = 0.001). A good correlation (ρ = 0.861, p < 0.001) was found between the FSI3 and objective scatter index provided by a commercial instrument.
CONCLUSION: Since aberrations have little impact on the FSI3 , the light scatter assessment becomes less dependent on the patient's refractive error compensation and the presence of higher-order aberrations. The FSI3 can further the clinical and scientific understanding of forward intraocular scattering.
METHODS: A prospective observational study was carried out in the Department of Ophthalmology, Hospital Universitari Mútua de Terrassa (Spain) on a group of 19 patients diagnosed with nuclear cataracts of various LOCSIII grades and a control group (CG) with nine healthy eyes. We recorded double-pass retinal images with a custom set-up based on a high-sensitivity digital camera. The FSI3 was then computed using spatial frequencies below three cycles per degree. A preliminary validation of the FSI3 was performed on an artificial eye and two eyes of volunteers with and without commercial diffusers, and under defocus.
RESULTS: The FSI3 was hardly affected by defocus values up to 2.50 D. The mean (and standard deviation) FSI3 values were as follows: for the CG, 1.19 (0.21); and for LOCSIII grades nuclear opacity 1, 2 and 3, 1.30 (0.12), 1.62 (0.21) and 1.85 (0.21), respectively. Eyes with cataracts showed FSI3 values significantly different than healthy eyes (p = 0.001). A good correlation (ρ = 0.861, p < 0.001) was found between the FSI3 and objective scatter index provided by a commercial instrument.
CONCLUSION: Since aberrations have little impact on the FSI3 , the light scatter assessment becomes less dependent on the patient's refractive error compensation and the presence of higher-order aberrations. The FSI3 can further the clinical and scientific understanding of forward intraocular scattering.