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J. Pujol, M. Vilaseca, A. Salvadó, M. J. Romero, G. Pérez, L. Issolio, P. Artal; Cataract Evaluation With an Objective Scattering Index Based on Double-Pass Image Analysis. Invest. Ophthalmol. Vis. Sci. 2009;50(13):6127.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the amount of intraocular scattering in cataract patients by using the Objective Scatter Index (OSI) provided by a double-pass instrument. We establish a quantitative comparison between this objective evaluation and some subjective procedures commonly employed to evaluate cataracts such as visual acuity (VA) and slit-lamp examination.
We selected a group of patients in different levels of cataract development from early stages to mature levels. A control group of young normal eyes was also evaluated with the same procedure. The subjective procedure consists in a preliminary exam of the VA with and without correction (UCVA and BSCVA) and the direct observation of the crystalline lens by the slit-lamp image from which a first gradation of the state of every cataract eye is assessed (from 0 to 4). The analysis by the double-pass instrument (OQAS, Visiometrics SL, Spain) provides an objective quantification of intraocular scattering not affected by the contribution of the ocular aberrations (Alcon et al. ARVO 2007).
The scatter index (OSI) provided a robust tool to objectively classify cataract patients: OSI<2 for eyes without cataract, 2<OSI<5 for early cataracts and OSI>5 for the mature cataract eyes. In most of the patients, we find a correlation between the value of OSI and the BSCVA and UCVA and the previous classification by the slit-lamp images. However, some noticeable differences suggest the convenience of using an objective parameter to establish the severity of the cataract and its actual impact on the retinal image.
We evaluated the feasibility of using a scatter parameter OSI as a standard procedure in clinical environments to quantify the severity of cataracts. This objective parameter helps to take a sound decision about the convenience of scheduling the cataract surgery.
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