Subjektivní a objektivní vlastnosti bangerterových okluzorů
| Title in English | Subjective and objective qualities of Bangerter's occluders |
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| Authors | |
| Year of publication | 2014 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | The study investigated the efficiencies of two commercially available series of Bangerter diffusional occluders and two reference series (biconvex optical lenses and progressively multilayered diffusive foils) in the reduction of image quality. The aim is to compare objective metric of image degradation parameters and subjectively perceived changes of visual targets. Objective characteristics were measured by means of PSF (Point Spread Function; He- Ne laser 632.8 nm, a spatial filter, collimator, aperture 3.5 mm, digital camera). By calculating the Fourier transform of the PSF samples in each filter was set out the modulation transfer function (MTF) and described the shape of the MTF curves and integral MTF criterion. Subjective measurements obtained the best corrected visual acuity (ETDRS optotype, VectorVision, USA) and contrast sensitivity (standard chart for 1.5, 3 , 6 , 12 , 18 CPD, VectorVision, USA), measured under photopic conditions recommended by the FDA for multicenter clinical trials at 85 cd/m2. The results of the study proved accordance between objective and subjective parameters. In particular measurements, commercially distributed series of the Bangerter filters lack harmonic progression of optical properties and were discordant to declared gradation of the diffusional properties both in higher and in lower spatial frequencies. |