Intraocular Scattering Gradation from Double-Pass MTF Analysis

JOAN MARTINEZ-RODA; MERITXELL VILASECA; JUAN CARLOS ONDATEGUI-PARRA; CLEMENTE PAZ; SÁNCHEZ ROBERTO FRANCISCO; SERGIO LUQUE; JAUME PUJOL

Fort Lauderdale,Florida

Congreso; ARVO 2012 Annual Meeting; 2012

ARVO

Purpose: To objectively estimate the intraocular scattering by means of a new index (Frecuency Scattering Index,FSI), which is computed by using the whole double-pass (DP) image. The index proposed takes into account the maximum variation of the slope of the modulation transfer function (MTF) obtained from the DP image recorded. Methods: We selected a group of 50 patients with different grades of nuclear cataracts, including from early to moderate stages according to the LOCS III classification system (from NO1 to NO3). A control group of 10 young normal eyes was also evaluated with the same procedure. DP images (size: 72 arc min) were obtained using a clinical instrument (OQAS, Visiometrics SL, Spain). From those images the FSI was computed by means of the corresponding MTF images and the analysis of their maximum slope. The FSI index was then compared with the OSI values (Objective Scatter Index) in terms of correlation. The OSI was provided by the OQAS instrument (Artal et al Plos 2011). The influence of low-order aberrations on the FSI was also analyzed by performing measurements on 8 healthy young subjects with induced defocus from -1.50 to +1.50 D in 0.25 D steps. These results were compared with those obtained by using the OSI parameter. Results: For the control group and patients with different cataract grades, a statistically significant correlation (r=0.726, p