Effect of Dioptric Blur on Pattern-Reversal and Motion-Onset VEPs as Used in Clinical Research

Kordek, David; Voda, Petr; Young, Laura K.; Kremláček, Jan

doi:10.1167/tvst.11.12.7

Cited by 5 publications

(6 citation statements)

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“…It should be noted that these authors only considered VEP components up to ~170ms and thus did not examine post-stimulus latencies encompassing the time window here when we observed our group-wise differences. Other studies have found that blur-induced changes on VEP amplitude and latency depend on the stimuli used, with effects occurring for high but not low spatial frequency stimuli 83 . Specifically, induced blur affected pattern-reversal VEPs, but not motion-onset VEPs.…”

Section: Discussionmentioning

confidence: 92%

Cortical Visual Processing Differences in Myopia and Blur

Steinfeld,

Murray

2024

Preprint

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PurposeMyopia is projected to impact over 50% of the global population by 2050. However, we currently know little of the consequences of myopia on visual brain functions. Theoretical models point to a key role of optical blur in myopia’s natural history. Moreover, myopia is linked to long-lasting changes in cortical visual areas. We thus hypothesized that adults suffering from moderate myopia process visual stimuli under optical blur differently than emmetropic adults.MethodsEmmetropes (n=12, malesn=3, femalesn=9) and low to mild myopes(n=13, malesn=4, femalesn=9) were tested in the condition of -3 diopters of lens-induced blur. Participants performed an illusory contour recognition task while high-density EEG was recorded and analyzed using an electrical neuroimaging framework.ResultsWe provide evidence for cortical processing differences between emmetropes and mild myopes – both of whom were tested under -3D of defocus. From topographic modulations it followed that emmetropes and mild myopes engage (partially) distinct networks of brain regions. Source estimations localized these differences to the medial portion of the occipital pole. Moreover, the predominant topography of the VEP during this period not only correlated with SRE, but also was an excellent classifier of myopia vs. emmetropia. By contrast, our analyses provided no evidence for differences in visual completion processes.ConclusionsTo our knowledge, this is the first study of myopia pairing high density EEG and a behavioral task. Collectively, this pattern of findings supports a model of myopia wherein low-level visual cortices are impacted at relatively late post-stimulus processing stages.

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Section: Discussionmentioning

confidence: 92%

Cortical Visual Processing Differences in Myopia and Blur

Steinfeld,

Murray

2024

Preprint

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“…Peak times P100 and N2 and interpeak amplitudes PR-Am (A_P100 -(A_N75 + A_N145)/2) and, MO-Am ((A_P1 + A_P2)/2 -A_N2) were used for subsequent analysis, a methodology analogous to our previous study 7 .…”

Section: Discussionmentioning

confidence: 99%

“…During the review process, a question arose as to whether a highcontrast structure, particularly one that is used for pattern-reversal VEP, could also be used for vision with refractive errors testing similar way as the low-contrast low spatial frequency structure. The presence of high spatial frequencies or high contrast may interfere with the resistance of the MO VEP to dioptric blur 7 . In the current study, we used a high-contrast checkerboard pattern (Michelson contrast 96%) with spatial frequencies exceeding 10 c/deg.…”

Section: Discussionmentioning

confidence: 99%

“…In these studies, a high degree of dependence of key VEP parameters on the spatial frequency of the stimuli has been demonstrated. Specifically, it has been shown that with increased blurring of the images (due to refractive errors), there is a significant increase in the peak time of the P100 component and a decrease in its amplitude [5][6][7] (for review see 8 ).…”

Section: Introductionmentioning

confidence: 99%

“…Examples of such VEP examinations are motion-onset VEPs (MO VEPs), which can also be elicited in the periphery of the visual field [9][10][11] by stimulating patterns with low spatial frequencies. The dependence of the characteristics of MO VEPs on artificially (dioptrically) induced refractive error was investigated by Kordek et al 2022 7 . It was observed that dioptric blur significantly prolongs peak times and reduces interpeak amplitudes of PR VEPs, but not of MO VEPs.…”

Section: Introductionmentioning

confidence: 99%

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Can motion onset VEPs see through the blur?

Kordek,

Young,

Voda

et al. 2024

Preprint

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Motion-onset visual evoked potentials (MO VEPs) are robust to dioptric blur when low contrast and low spatial frequency patterns are used for stimulation. To reveal mechanisms of MO VEPs robustness, we studied whether the resistance to defocus persists even when using a high-contrast checkerboard using digital defocus in the emmetropic eyes of 13 subjects (males 20–60 years). We compared the dominant components of MO VEPs to pattern-reversal VEPs (PR VEP), which are sensitive to the blur. For stimulation, we used checkerboard patterns with 15´ and 60´ checks. To defocus the checkerboard, we rendered it with a second-order Zernike polynomial (\({Z}_{2}^{0}\)) with an equivalent defocus of 0, 2, or 4 D. For PR VEP, the checkerboards were reversed in terms of their contrast. To evoke MO VEP, the checkerboard of 60´ checks moved for 200 ms with a speed of 5 or 10 deg/s in the cardinal directions. The MO VEP did not change in peak time (P ≥ 0.0747) or interpeak amplitude (P > 0.0772) with digital blur. In contrast, for PR VEP, the results showed a decrease in interpeak amplitude (P ≤ 6.65ˑ10 − 4) and an increase in peak time (P ≤ 0.0385). Thus, we demonstrated that MO VEPs evoked by checkerboard, structure containing high spatial content, can be robust to defocus.

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