Impact of scatter on double-pass image quality and contrast sensitivity measured with a single instrument

Abstract

Abstract:We compared objective Double-Pass (DP) image quality data with subjective visual parameters measured within the same modified instrument for different amounts of scatter. The original DP imaging channel of a clinical instrument was maintained intact and two additional channels were included, one for visual testing and another for tear film (TF) imaging by using a retro-illumination technique. Contrast sensitivity (CS) was compared with measurements of the Objective Scattering Index (OSI) obtained from DP retinal images corresponding to different scatter levels induced by pre-defined filters. OSI values were correlated with the change in CS for different spatial frequencies measured with the same instrument. Since TF and DP images were recorded at the same rate, this provided additional information about the dynamic spatial stability of the tear film. This new DP instrument has been proven to provide accuracy and repeatability, and to be suitable for clinical diagnosis, with a complete evaluation of the eye's performance by a simultaneous objective and subjective assessment under the same experimental conditions.

Effect of higher-order aberrations and intraocular scatter on contrast sensitivity measured with a single instrument

“…Figure 6 shows the results of CSF for all subjects measured with and without scatter filters. It can be observed that the CS decreased with increasing scatter for each spatial frequency, which was consistent with the previous results reported by Bueno et al [10]. For a better understanding of the effect of scatter on visual performance, parameter Impact factor Scatter was computed for each scatter filter and spatial frequency.…”

“…Results showed that CS decreased with increasing scatter and AO correction of HOAs improved CS in all spatial frequencies for each subject, suggesting that both HOAs and intraocular scatter played an essential role in the CSF. To date, there have been several studies [8,10] assessing the respective effect of HOAs and intraocular scatter on CSF, and similar results were reported. Kang et al [8] measured the CS with and without HOAs correction, and their results showed that AO correction of HOAs improved CS for all spatial frequencies in all eyes.…”

“…Kang et al [8] measured the CS with and without HOAs correction, and their results showed that AO correction of HOAs improved CS for all spatial frequencies in all eyes. Bueno et al [10] measured CS with different scatter levels induced by pre-defined filters, they found that CS decreased with increasing scatter for each spatial frequency.…”

“…Intraocular scatter is another important optical factor affecting CS. There have been several studies [9][10] assessing the effect of intraocular scatter on CS, and inconsistent conclusions were made from the experimental data. Using the statistical analysis method, Lee et al [9] compared parameters of the double-pass (DP) system with the CS.…”

“…They discovered that the objective scatter index (OSI) was not correlated with CS at any spatial frequencies. In a more recent study, Bueno et al [10] measured CS with different scatter levels induced by pre-defined filters. The results indicated that CS decreased with increasing scatter for all spatial frequencies.…”