Chromatic stimulus for accommodation to stationary and moving targets

Kruger, Philip B.; Mathews, Steven; Aggarwala, Karan R.; Stark, Lawrence; Bean, Sharon; Lee, J.; Cohen, Sara

doi:10.1007/978-3-0348-7586-8_18

Cited by 1 publication

(6 citation statements)

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“…The resultant dioptric stimulus levels for the 2.4 m (+0.416 D) viewing conditions were +1.916 D, −1.08 D or +0.416 D, not correcting for LCA. A middle‐of‐the‐road estimate of the LCA resulting from the tinted blue lens may approximate +0.75 D (Kruger et al. , 2000).…”

Section: Methodsmentioning

confidence: 99%

“…The resultant dioptric stimulus levels for the 2.4 m (+0.416 D) viewing conditions were +1.916 D, )1.08 D or +0.416 D, not correcting for LCA. A middle-of-the-road estimate of the LCA resulting from the tinted blue lens may approximate +0.75 D (Kruger et al, 2000). Taking LCA into account, the net dioptrical stimulus levels may accordingly average +1.83 D (+1.5 D lens condition), )1.17 D ()1.5 D lens condition), and +0.33 D (0 D lens condition).…”

Section: Measurement Of Csmentioning

confidence: 99%

“…Shifts of attention guide the eye to a target of interest and the lens of the eye assumes a more convex shape when gaze is directed at a nearby object. Although the anatomical and physiological basis for this process is becoming more understood, the precise features of the wavelength stimulus to accommodation are still uncertain (Fincham, 1951;Kruger et al, 2000;Rucker and Kruger, 2004). Till date, few studies have focused on control processes within the accommodative/vergence system that differentiate asthenopics from asymptomatic subjects under short-wavelength viewing conditions.…”

Section: Introductionmentioning

confidence: 99%

“…the eye would have to decrease its accommodation to focus short wavelengths on the retina). Thus, when the eye has accommodated accurately for only some of the wavelengths, generally assumed to be those in the middle of the range, the others are permitted to be out of focus (Kruger et al, 2000;Rucker and Kruger, 2004). There is currently no agreement regarding the actual wavelengths that should be assumed to constitute the reference wavelength (Kruger et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Superior short‐wavelength contrast sensitivity in asthenopics during reflexive readjustments of ocular accommodation

Richter

Knez

2007

Ophthalmic Physiologic Optic

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The purpose of this work was to characterize contrast sensitivity (CS) under short-wavelength illumination in 20 symptom-free subjects and eight asthenopics: all had normal unaided or corrected visual acuity and no sign of oculomotor disease. Threshold CS was assessed using the von Békésy tracking method from a viewing distance of 2.4 m (0.40 D). Three counterbalanced tasks required central fixation of black-and-white square-wave gratings (1, 5, 10, 14 and 17 c/deg) presented through a low-pass filter blue lens and (1) a +1.50 D lens; (2) a -1.50 D lens and (3) a 0 D lens, while attempting accommodation to minimize blur. Baseline increases in eye strain, which approached high levels at the end of the experiment, did not differentiate between the two groups of volunteers. All the subjects made evident appropriate accommodation during the low blur condition (0 D); the CS curve exhibited the expected characteristics. When the minus lens was placed before the eyes of the observers the distant square-wave gratings were still seen clearly, the eyes presumably had accommodated by an amount equal to the power of the negative lens. Compared with symptom-free subjects, asthenopics exhibited greater CS at the intermediate spatial frequencies both during the low blur and the minus blur conditions. Asthenopics may exhibit an individualized sensory tendency to react more strongly to shorter wavelengths of light and may therefore reflexively 'drive' their accommodative system harder than symptom-free subjects. This would explain the presence of their asthenopia in the first place. Blue light may, in addition, induce more arousal and higher alertness in this category of participants. This would boost the oculomotor aspects of their performance. These findings add to the current understanding of individual variability in the level of oculomotor loads following strenuous near work.

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Section: Methodsmentioning

confidence: 99%

Section: Measurement Of Csmentioning

confidence: 99%