Ocular residual astigmatism: Effects of demographic and ocular parameters in myopic laser in situ keratomileusis

Фрингс, Андреас; Katz, Toam; Steinberg, Johannes; Druchkiv, Vasyl; Richard, Gisbert; Linke, Stephan J.

doi:10.1016/j.jcrs.2013.11.015

Cited by 33 publications

(26 citation statements)

References 17 publications

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“…It is not clear if the same would be true for other samples with higher amounts of RA, but Shankar and Bobier 11 found no difference in IA between higher and lower RA in children 3 to 5 years of age. Others have also not been very successful in finding useful predictors of higher amounts of calculated IA, though males were found to be 26% less likely than females to have IA ≥ 1.00D 14 . Park and colleagues 7 reported that since the mean spherical equivalent was negatively correlated with IAJ0 and RA was positively correlated with IAJ0, RA and mean spherical equivalent might be predictors of IA.…”

Section: Discussionmentioning

confidence: 99%

“…Other terms for IA, reflecting the uncertainty of its origin, include: physiological astigmatism (see 5 for the evolution of this terminology), residual astigmatism 2 , ocular residual astigmatism 7 , intraocular, lenticular or non-corneal astigmatism 10 . Although originally regarded as a mathematical constant of −0.50 to −0.75D axis 90 (Javal 1890 as cited by Kratz and Walton 5 ), investigators have questioned if IA plays an active compensatory role in reducing RA 11,12 or is influenced by refractive error 7, 13, 14 . Internal astigmatism has also been of interest to refractive and cataract surgeons desiring to minimize astigmatism derived from intraocular components that may manifest following alteration of the cornea or removal of the lens.…”

mentioning

confidence: 99%

“…Internal astigmatism has also been of interest to refractive and cataract surgeons desiring to minimize astigmatism derived from intraocular components that may manifest following alteration of the cornea or removal of the lens. 7, 10, 14, 15 …”

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confidence: 99%

“…Park et al 7 did confirm the general compensatory role of IA in reducing the corneal contribution to RA and explored factors that might predict high IA in a group of myopic patients, a useful tool that would assist the surgeon in determining the optimal power for intra-ocular lenses 15,22 or better predict outcomes from corneal refractive surgery 7,10,14 . They reported a significant correlation between IA and the mean spherical equivalent and between IA and RA.…”

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confidence: 99%

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Internal Astigmatism in Myopes and Non-myopes: Compensation or Constant?

Manny¹,

Deng

Gwiazda

et al. 2016

Optom Vis Sci

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Purpose To examine internal astigmatism (IA) in myopes and non-myopes using a new method to assess compensation of corneal astigmatism (CA) by IA, to look for predictors of high IA in young adult myopes and determine if as CA changes IA changes to reduce refractive astigmatism (RA) in an active compensatory process in myopes. Methods Right eye keratometry and cycloplegic autorefraction were measured annually over 14 years in 367 myopes and once in 204 non-myopes age- (mean 21.91 years ± 1.47), gender-, and ethnicity-matched to myopes at year 12. CA and RA at the corneal plane were expressed as J0, J45. IA = RA - CA. Inverse power transformation provided cylinder power and axis of IA for the compensation factor (IA/CA). Analyses included: 1) paired and unpaired t-tests (refractive data), 2) chi-square tests (distributions of compensation factor), 3) logistic regression analysis (predictors of high IA), and 4) linear mixed models (time effect on RA, CA and IA). Results The magnitude of IAJ0 varied by refractive error (myopes −0.25 ±0.24 vs non-myopes −0.32 ± 0.21, p<0.001). Compensation of CA by IA was poorer in myopes than non-myopes (χ2 p<0.001). When matched by CA, compensation remained poorer in myopes than non-myopes (χ2 all p≤ 0.04). Within each refractive group compensation was better when CA was low than high (χ2 p<0.001). When CA was low in myopes, high IA (≥1.00D) was less likely (p=0.01). Longitudinal follow-up of myopes found no evidence for an active compensatory role for IA as CA increased over time. There were differences in IAJ0 by ethnicity over time (p<0.0001). Conclusions In myopic and non-myopic eyes with low amounts of CA, IA may reduce CA’s contribution to RA, but IA is not a constant. However, there is no evidence for an active compensatory role for IA reducing CA in myopes.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Internal Astigmatism in Myopes and Non-myopes: Compensation or Constant?

Manny¹,

Deng

Gwiazda

et al. 2016

Optom Vis Sci

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“…The introduction of toric intraocular lens (IOL) technology has made it possible to offer better and more stable uncorrected visual acuity to patients with astigmatism. In clinical practice, however, some patients still present with postoperative refractive astigmatism of unknown origin even with toric IOL implantation, and the accuracy of preoperative measurements of corneal astigmatism is often discussed [2, 3]. …”

Section: Introductionmentioning

confidence: 99%

Influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery

et al. 2016

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BackgroundTo examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery.MethodsThe study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-keratometer with a 0.01- diopter (D) scale. Two types of corneal astigmatism were calculated using anterior segment optical coherence tomography; keratometric and total corneal astigmatism. Keratometric astigmatism was obtained based on anterior corneal curvature alone and total corneal astigmatism was calculated using both anterior and posterior corneal curvatures. The difference between refractive and corneal astigmatism was computed as the vector difference using 1) refractive and keratometric astigmatism and 2) refractive and total corneal astigmatism.ResultsThe mean refractive, keratometric, and total corneal astigmatism was 0.92 ± 0.48 D, 0.87 ± 0.44 D, and 0.94 ± 0.46 D, respectively. The difference between refractive and keratometric astigmatism (0.70 ± 0.40 D, mean vector of 0.30 D axis 164°) was significantly larger than the difference between refractive and total corneal astigmatism (0.63 ± 0.38 D, mean vector of 0.12 D axis 137°) (P = .019).ConclusionsThe difference between refractive and total corneal astigmatism, calculated using both anterior and posterior corneal curvatures, was significantly smaller than the difference between refractive and keratometric astigmatism using anterior corneal astigmatism alone, implying that the latter overestimates the true postoperative refractive astigmatism and can cause cylindrical inaccuracy after cataract surgery.

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