Noise in Wavefront Error Measurement from Pupil Center Location Uncertainty

Applegate, Raymond A.; Marsack, Jason D; Sarver, Edwin J.

doi:10.3928/1081597x-20100921-05

Cited by 17 publications

(14 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…When a lens is not stable or is misaligned, aberration correction is reduced, and can actually lead to an increase in higher-order aberration and a reduction in visual performance. 27-29 …”

mentioning

confidence: 99%

Wavefront-Guided Scleral Lens Correction in Keratoconus

Marsack¹,

Ravikumar²,

Nguyen

et al. 2014

Optometry and Vision Science

Self Cite

View full text Add to dashboard Cite

Purpose To examine the performance of state-of-the-art wavefront-guided scleral contact lenses (wfgSCLs) on a sample of keratoconic eyes, with emphasis on performance quantified with visual quality metrics; and to provide a detailed discussion of the process used to design, manufacture and evaluate wfgSCLs. Methods Fourteen eyes of 7 subjects with keratoconus were enrolled and a wfgSCL was designed for each eye. High-contrast visual acuity and visual quality metrics were used to assess the on-eye performance of the lenses. Results The wfgSCL provided statistically lower levels of both lower-order RMS (p < 0.001) and higher-order RMS (p < 0.02) than an intermediate spherical equivalent scleral contact lens. The wfgSCL provided lower levels of lower-order RMS than a normal group of well-corrected observers (p < < 0.001). However, the wfgSCL does not provide less higher-order RMS than the normal group (p = 0.41). Of the 14 eyes studied, 10 successfully reached the exit criteria, achieving residual higher-order root mean square wavefront error (HORMS) less than or within 1 SD of the levels experienced by normal, age-matched subjects. In addition, measures of visual image quality (logVSX, logNS and logLIB) for the 10 eyes were well distributed within the range of values seen in normal eyes. However, visual performance as measured by high contrast acuity did not reach normal, age-matched levels, which is in agreement with prior results associated with the acute application of wavefront correction to KC eyes. Conclusions Wavefront-guided scleral contact lenses are capable of optically compensating for the deleterious effects of higher-order aberration concomitant with the disease, and can provide visual image quality equivalent to that seen in normal eyes. Longer duration studies are needed to assess whether the visual system of the highly aberrated eye wearing a wfgSCL is capable of producing visual performance levels typical of the normal population.

show abstract

“…When a lens is not stable or is misaligned, aberration correction is reduced, and can actually lead to an increase in higher-order aberration and a reduction in visual performance. 27-29 …”

mentioning

confidence: 99%

Wavefront-Guided Scleral Lens Correction in Keratoconus

Marsack¹,

Ravikumar²,

Nguyen

et al. 2014

Optometry and Vision Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…Several factors and conditions are expected to impact the correlation between longitudinal change in optical quality and longitudinal change in acuity, including: 1) adaptation 15-18 to one’s slowly changing retinal image quality; 2) the repeatability of both wavefront error 19-21 and acuity measurements 22 is not perfect; and 3) changes in acuity may be related to other factors, such as neurological changes (e.g., neural cell loss or functional decline not measured by optical quality metrics calculated from WFE alone), that may subsequently be accounted for when age is included as a metric. 23-26 …”

mentioning

confidence: 99%

Factors Accounting for the 4-Year Change in Acuity in Patients Between 50 and 80 Years

Koenig

Nguyen

Parker

et al. 2013

Optometry and Vision Science

Self Cite

View full text Add to dashboard Cite

Purpose It is well known acuity slowly decreases in later decades of life. We wish to determine the extent 4 year longitudinal acuity changes can be accounted for by changes in optical quality, or combination of optical quality metrics and age between 50 and 80. Methods High contrast logMAR acuity, 35 image quality metrics, 4 intraocular scatter metrics, and 4 Lens Opacification Classification System-III metrics and entry age were measured on one eye of each of 148 subjects. Acuity change between baseline and the last visit was regressed against change in each metric for all eyes and a faster changing subset of 50 eyes with a gain or loss of 4 or more letters. Results Average change across 148 subjects was a 1.6 ± 4 letter loss (t148 = 4.31, p < 0.001) and loss for the faster changing subset was 3.4 ± 6.1 letters (t50 = 2.73, p = 0.008). The multiple-regression model for faster changing eyes included change in point spread function entropy, posterior subcapsular cataract, and trefoil and baseline age (sequential r2-adj values 0.19, 0.27, 0.32, 0.34 respectively p = 1.48×10−4 for the full 4 factor model). The same variables entered the multiple-regression model for the full 148 data set where the majority of the acuity measurements were within test re-test error and accounted for less of the variance (r2-adj = 0.15, p = 2.37×10−5). Conclusions Despite being near noise levels for the measurement of acuity, change in optical quality metrics were the most important factors in eyes that lost or gained 4 or more letters of acuity. These findings should be generalizable given our four year acuity change is essentially identical to other studies, and indicate these optical quality markers can be used to help identify those on a faster track to an acuity change.

show abstract

“…. The usefulness of a simplified representation, with higher order aberrations expressed as a Zernike vector term, was reported previously [26][27][28][29][30][31][32]. We also investigated each Zernike coefficient of higher order aberrations, such as…”

Section: Methodsmentioning

confidence: 97%