The Effects of Central and Peripheral Refraction on Critical Fusion Frequency

Abstract

Absirael-The critical fusion frequency (CFF) ol" each eye of one subjeci is measured for various combinations of focus and retinal posilion. Large (50 min arc) and small (8 min arc) flickering sources are used. Wiih the 8 min arc source, the axial CFF is very sensitive lo defocus and is halved by 2.00 DS of blur. The relinal periphery is less sensitive lo defocus, and ihe naiurally occurring oblique astigmatism of the peripheral media is typically insufficient lo subsianiially affeci CFF.

A Critical Evaluation of Refractive Outcomes Following LASIK for Moderate to High Astigmatism Using Two Excimer Laser Platforms

“…A difference between a pair of SIA and TIA powers values could be due to the typical error in subjective refraction, which is reported to range from ±0.34 D in the younger population and ±0.51 D in the older population. [11][12][13] The high significance of the multiple and single linear regression analyses would not have been encountered if differences between SIA and TIA arose from totally random events associated with subjective refraction alone.…”

A Critical Evaluation of Refractive Outcomes Following LASIK for Moderate to High Astigmatism Using Two Excimer Laser Platforms

“…A difference between a pair of SIA and TIA powers values could be due to the typical error in subjective refraction, which is reported to range from ±0.34 D in the younger population and ±0.51 D in the older population. [11][12][13] The high significance of the multiple and single linear regression analyses would not have been encountered if differences between SIA and TIA arose from totally random events associated with subjective refraction alone.…”

Optimal spherical focus in the peripheral retina

“…oblique astigmatism (Wang et al, 1997). Measurements of detection thresholds with small targets (Fankhauser and Enoch, 1962;Anderson et al, 2001), luminance/ time reciprocity (Ronchi, 1971), motion detection thresholds (Johnson and Leibowitz, 1974) and critical fusion frequency (Jennings and Charman, 1981) are also all markedly affected by defocus. Thus it appears that optical quality is more relevant to dynamic than to static visual performance in the periphery.…”

An exploratory study of temporal integration in the peripheral retina of myopes

“…37,54,55 It is also known that astigmatism can have a pronounced detrimental effect on critical fusion frequency for small light sources. 56 Thus, we speculate that astigmatism is contributing to the poorer visual performance of the temporal retina.…”

A Critical Evaluation of Refractive Outcomes Following LASIK for Moderate to High Astigmatism Using Two Excimer Laser Platforms

“…A difference between a pair of SIA and TIA powers values could be due to the typical error in subjective refraction, which is reported to range from ±0.34 D in the younger population and ±0.51 D in the older population. [11][12][13] The high significance of the multiple and single linear regression analyses would not have been encountered if differences between SIA and TIA arose from totally random events associated with subjective refraction alone.…”

Optimal spherical focus in the peripheral retina

“…oblique astigmatism (Wang et al, 1997). Measurements of detection thresholds with small targets (Fankhauser and Enoch, 1962;Anderson et al, 2001), luminance/ time reciprocity (Ronchi, 1971), motion detection thresholds (Johnson and Leibowitz, 1974) and critical fusion frequency (Jennings and Charman, 1981) are also all markedly affected by defocus. Thus it appears that optical quality is more relevant to dynamic than to static visual performance in the periphery.…”

An exploratory study of temporal integration in the peripheral retina of myopes

“…37,54,55 It is also known that astigmatism can have a pronounced detrimental effect on critical fusion frequency for small light sources. 56 Thus, we speculate that astigmatism is contributing to the poorer visual performance of the temporal retina.…”

A Critical Evaluation of Refractive Outcomes Following LASIK for Moderate to High Astigmatism Using Two Excimer Laser Platforms

“…A difference between a pair of SIA and TIA powers values could be due to the typical error in subjective refraction, which is reported to range from ±0.34 D in the younger population and ±0.51 D in the older population. [11][12][13] The high significance of the multiple and single linear regression analyses would not have been encountered if differences between SIA and TIA arose from totally random events associated with subjective refraction alone.…”

Optimal spherical focus in the peripheral retina

“…oblique astigmatism (Wang et al, 1997). Measurements of detection thresholds with small targets (Fankhauser and Enoch, 1962;Anderson et al, 2001), luminance/ time reciprocity (Ronchi, 1971), motion detection thresholds (Johnson and Leibowitz, 1974) and critical fusion frequency (Jennings and Charman, 1981) are also all markedly affected by defocus. Thus it appears that optical quality is more relevant to dynamic than to static visual performance in the periphery.…”

An exploratory study of temporal integration in the peripheral retina of myopes

“…37,54,55 It is also known that astigmatism can have a pronounced detrimental effect on critical fusion frequency for small light sources. 56 Thus, we speculate that astigmatism is contributing to the poorer visual performance of the temporal retina.…”