Targeting Anterior Corneal Astigmatism With Topography-Guided Ablation Ignores Ocular Residual Astigmatism, Resulting in Inferior Outcomes

Wallerstein, Avi; Gauvin, Mathieu; Cohen, Mark E.

doi:10.3928/1081597x-20191210-01

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…In corneal refractive surgery, astigmatism correction is often performed based on the preoperative MA only or ACA only ( 8 ). These approaches may lead to suboptimum postoperative visual quality if patients have a significant ORA ( 9 , 10 ). A large number of studies have suggested that astigmatism correction by laser in situ keratomileusis (LASIK) can achieve a better correction outcome if the preoperative MA mainly comes from ACA ( 4 , 5 , 11 ).…”

Section: Introductionmentioning

confidence: 99%

The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

Tang

et al. 2022

Front. Med.

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PurposeWe aimed to investigate the distribution of ocular residual astigmatism (ORA) and its associations with age, gender, manifest refraction, and other ocular indicators in Chinese patients with myopia.DesignThis is a multi-center retrospective cross-sectional study.MethodThe study included 7,893 patients with myopia (7,893 eyes) aged 18–40 years from five ophthalmic centers. Anterior segment biometrics of the eyes were collected from the Pentacam. ORA and its summated vector mean were calculated using Alpins vector analysis. Compensation factor (CF) was used to evaluate the relation between ORA and corneal astigmatism. ORA in different age, gender, and refraction groups was compared. The Spearman correlation was adopted to reveal multiple ocular indicators associated with ORA, which were integrated into a multiple linear regression model to predict ORA.ResultsDistribution of ORA was slightly positively skewed (Skewness= 2.111, Kurtosis = 19.660, KS P < 0.0001). Mean ORA was 0.74 ± 0.39 D (95% normal range: 0.14–1.54 D). Among all the subjects, 22.4% of the eyes had an ORA magnitude of 1.0 D or more. Undercompensation or full-compensation of anterior corneal astigmatism (ACA) by ORA prevailed in both J0 (76.99%) and J45 (58.48%). Women had higher ORA power than men (0.77 ± 0.36 D vs. 0.73 ± 0.41 D, P < 0.0001). Participants with less negative spherical equivalent (SE) or higher manifest astigmatism (MA) also had higher ORA (all P < 0.0001). ORA was significantly correlated with ACA (r = 0.405) and posterior corneal astigmatism (PCA, r = 0.356). The multivariate logistic regression analysis showed strong predictability of ORA magnitude >1.0 D using anterior segment parameters (area under the receiver operating characteristic curve: 0.739).ConclusionORA is present in Chinese adults with myopia and is affected by multiple ocular factors. Our findings may provide valuable information about ORA distribution in candidates for refractive surgery, helping optimize the outcome of astigmatism correction.

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Section: Introductionmentioning

confidence: 99%

The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

Tang

et al. 2022

Front. Med.

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“…ORA is an important metric to assess the efficiency of astigmatism correction. There is evidence that eyes with low ORA (<1.0), are twice as likely to have effective treatment of astigmatism compared with eyes that have high pre-operative ORA (≥1.0) [17,18]. In this study, the pre-operative ORA for our sample was low with a mean of 0.76 ± 0.39D overall.…”

Section: Discussionmentioning

confidence: 57%

Comparison of the Clinical Effectiveness of Correcting Different Types of Astigmatism with Small Incision Lenticule Extraction

Igras,

Czarnota-Nowakowska,

O’Caoimh

2023

JCM

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Few studies have reported the differential outcomes of Small Incision Lenticule Extraction (SMILE) on myopic astigmatism. Given this, we examined the effectiveness of SMILE for up to one year, comparing with-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism, conducting a retrospective review of patients who underwent correction of myopic astigmatism using the 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec) at two refractive clinics in Poland between 2016–2017. Patients were aged ≥21 with stable refractive errors between −0.5 and −10.0 diopter (D) with astigmatism up to 5D. The mean age of the 209 patients (355 eyes) available was 32 years; 58.4% were female. Of these, 247 had WTR, 62 oblique, and 46 ATR astigmatism. The mean pre-operative spherical equivalent (SE) was −5.4 ± 2.57D and the cylinder −1.7 ± 1.0D. The mean SE for WTR reduced from −5.60 ± 2.37D to −0.31 ± 0.67D at 2 months and −0.38 ± 0.70D at 12 months; the mean cylinder improved from −1.90 ± 1.10D to −0.31 ± 0.39D and −0.36 ± 0.43D, respectively. Eyes with oblique astigmatism also improved from a mean SE of −5.8 ± 3.4 D to −0.82 ± 1.50D and −0.69 ± 1.15D and a cylinder of −1.4 ± 0.73D to −0.17 ± 0.33D at 2 months and −0.1 ± 0.32D at 12. For ATR, the mean SE improved from −4.0 ± 1.8D to −0.08 ± 0.22D and −0.04 ± 0.12D; and the mean cylinder from −1.25 ± 0.53 to −0.02 ± 0.09D −0.08 ± 0.21D at 2 and 12 months, respectively. There were statistically significant improvements in SE, manifest sphere and cylinder refraction, and UDVA and CDVA scores for each cylinder type at 2 months with ATR cylinders having better outcomes. Although missing data limited interpretation at one year, differences were maintained. The magnitude of error calculations suggests that WTR was more prone to under-correction, particularly for high astigmatism (>1.5D). SMILE for myopic astigmatism reliably corrects SE, irrespective of the subtype of astigmatism.

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The contribution of ocular residual astigmatism to anterior corneal astigmatism in refractive astigmatism eyes

Lin

2021

Sci Rep

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To determine the distribution of ocular residual astigmatism (ORA) in astigmatic eyes and the influence on the anterior corneal (ACA) and refractive astigmatism (RA). A total of 165 children met the inclusion criteria. Right eyes’ data were analyzed. Using Thibos vector analysis to calculate ORA. Spearman correlation analysis was used to obtain the correlation between the magnitude of ORA, ACA and RA. The median magnitude of ORA in astigmatic eyes was 0.57 D, with interquartile range was 0.42 D. And they were main against-the-rule (57.6–75.8%) and oblique astigmatism (13.9–34.5%) ORA. The ORA in 140 eyes (84.8%) acted as an offset to ACA, meanwhile, 25 eyes (15.2%) superimposed it. About 98% (97.9–98.4%) against-the-rule and 75% (73.9–82.5%) oblique ORA counteracted ACA, nevertheless, all with-the-rule ORA had a superimposed effect on ACA. For with-the-rule ACA, about 86% (85.4–85.9%) ORA worked to offset it. There was statistically correlations between ORA and ACA (r = 0.17, P = 0.03), ORA and RA (r = − 0.27, P = 0.001). The magnitude of ocular residual astigmatism was relatively small in children’s astigmatic eyes. Both against-the-rule and oblique ORA can counteract with-the-rule ACA.

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Targeting Anterior Corneal Astigmatism With Topography-Guided Ablation Ignores Ocular Residual Astigmatism, Resulting in Inferior Outcomes

Cited by 5 publications

References 7 publications

The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

Comparison of the Clinical Effectiveness of Correcting Different Types of Astigmatism with Small Incision Lenticule Extraction

The contribution of ocular residual astigmatism to anterior corneal astigmatism in refractive astigmatism eyes

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