Integrated light scattering as a function of wavelength in donor lenses

Thaung, Jörgen; Sjöstrand, Johan

doi:10.1364/josaa.19.000152

Cited by 13 publications

(6 citation statements)

References 19 publications

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“…We also found a similar visual acuity ($1.3 in decimal units) for fog with a visibility V = 15 m (Ozolinsh et al, 2006). This shows that, with a PDLC Thaung and Sjostrand (2002); and van den Berg (1997).…”

Section: Discussionsupporting

confidence: 81%

Light scattering in artificial fog and simulated with light scattering filter

Ikaunieks

Colomb

Ozolinsh

2009

Ophthalmic Physiologic Optic

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Disability glare, affecting e.g. road safety at night, may result either from intraocular light scattering or from external conditions such as fog. Measurements were made of light scattering in fog and compared with intraocular straylight data for normal eyes and eyes with simulated cataract. All measurements were made with a direct compensation flicker method. To estimate light scattering levels in fog, straylight measurements were carried in a fog chamber for different densities of fog. Density was characterized by the meteorological term visibility V and ranged from 7 to 25. Test distance for measurements in the fog was constant at 5 m. Cataract eye conditions were simulated by placing a light scattering polymer dispersed liquid crystal (PDLC) filter with scatterers of submicron size in front of the normal eye. All measurements were made using each of three broad-band color stimuli - red, green and blue (produced either with LEDs or a color CRT monitor). Differences were found in both the level and the spectral characteristics of scattering under the different conditions. The measured values of the straylight parameter, s, in artificial fog showed no noticeable spectral dependence at any visibility range. Increasing the visibility range caused an exponential decrease in the straylight. Intraocular straylight measured with the clear eye showed an increase at the red and blue ends of the spectrum as compared to the green. Straylight measured using PDLC plates with different transparency levels showed a spectral dependence which decreased with wavelength. The scattering introduced by the PDLC plate therefore failed to give a valid simulation of cataract and fog conditions for polychromatic stimuli, due to its erroneous spectral dependence.

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Section: Discussionsupporting

confidence: 81%

Light scattering in artificial fog and simulated with light scattering filter

Ikaunieks

Colomb

Ozolinsh

2009

Ophthalmic Physiologic Optic

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“…According to the light scatter theory, the intensity of light is weakened by either absorption or scattering, depending on the wavelength and the thickness of the media, through which the light has to pass (van den Berg & Ijspeert ; Thaung & Sjöstrand ). Techniques that allow for non‐invasive assessment of retinal haemodynamic, retinal vessel densitometry and bidirectional Doppler assessment, have already confirmed to be influenced by the cataract light induced scatter (Nagaoka et al.…”

Section: Discussionmentioning

confidence: 99%

Influence of cataract light scatters on retinal vessel oxygen saturation

Waizel

Türksever

Todorova

2019

Acta Ophthalmologica

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Background: The aim of our study was to compare metabolic (oxygen saturation; %) and anatomical parameters (retinal vessel diameter; lm) of retinal vessel oximetry (RO) in patients with cataract formation against those of healthy controls with clear lenses. Methods: A total of 96 eyes of 62 subjects were examined: 51 eyes from 33 cataract patients (mean age: 64.8y) were compared to 45 eyes from 29 controls with clear lenses (mean age: 61.5y). RO was performed with the oxygen saturation measurement tool from the RVA (IMEDOS Systems UG). The oxygen saturation in all major peripapillary retinal arterioles (A-SO 2 ) and venules (V-SO 2 ) was measured, and their difference (A-V SO 2 ) was calculated. In addition, the corresponding diameter in retinal arterioles (D-A) and venules (D-V) was evaluated. Cataract formation was graded according to the Lens Opacities Classification System III (LOCS III). Oximetry data were compared with the grade of cataract formation within both groups. For statistical evaluation, ANOVAbased linear mixed-effects models were calculated (SPSS â , pairwise comparisons: Bonferroni-corrected; p < 0.05). Results: Cataract eyes showed significantly lower A-SO 2 and A-V SO 2 values (mean AE SD 92.52 AE 9.80% and 28.56 AE 9.80%), when compared to healthy controls (95.47 AE 4.48% and 34.8 AE 7.08%; p = 0.046 and p = 0.001). Within the cataract group, cortical opacities showed significant interactions with the A-SO 2 , V-SO 2 and the A-V SO 2 parameters (p = 0.027; p = 0.002; and p = 0.026, respectively). Conclusions: These data indicate that the cataract-induced light scatter influences optical retinal oxygen measurements. Cortical opacities showed the highest influence on RO measurement when compared to nuclear opacification, nuclear colour and posterior cataract formation.

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“…According to the scatter theory and studies on excised lenses, light scattering in the lens is wavelength dependent (van den Berg & Ijspeert 1995; Thaung & Sjöstrand 2002). Light scatter in donor lenses increases monotonically from 700 nm towards 400 nm (van den Berg & Ijspeert 1995; Thaung & Sjöstrand 2002); therefore, there is a greater degree of scatter for shorter wavelength light. This wavelength dependency is greater in older patients (van den Berg & Ijspeert 1995).…”

Section: Discussionmentioning

confidence: 99%

The impact of cataract on the quantitative, non‐invasive assessment of retinal blood Flow

Azizi¹,

Wong²,

Wan³

et al. 2011

Acta Ophthalmologica

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Retinal vessel densitometry assessment in the presence of cataract results in the erroneous elevation of the diameter measurement and thereby the calculation of blood flow. The bidirectional Doppler assessment of blood velocity appears to be more robust to light scatter induced by cataract. Care needs to be exercised in the interpretation of studies of retinal vessel diameter or blood flow that utilize similar densitometry techniques.

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Integrated light scattering as a function of wavelength in donor lenses

Cited by 13 publications

References 19 publications

Light scattering in artificial fog and simulated with light scattering filter

Light scattering in artificial fog and simulated with light scattering filter

Influence of cataract light scatters on retinal vessel oxygen saturation

The impact of cataract on the quantitative, non‐invasive assessment of retinal blood Flow

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