Age‐related changes in with‐the‐rule and oblique corneal astigmatism

Næser, Kristian; Savini, Giacomo; Bregnhøj, Jesper Flethøj

doi:10.1111/aos.13683

Cited by 34 publications

(43 citation statements)

References 26 publications

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“…Other studies with wider age ranges reported greater changes in these indices. 38,39 In agreement with other studies, 40–42 our results indicated that females have more steep corneas. In contrast, Cheung et al 43 reported similar Q-values for the two genders, although the small sample size (63 subjects) and low power may be responsible for the non-significant inter-gender difference.…”

Section: Discussionsupporting

confidence: 93%

Total corneal refractive power and shape in Down syndrome

Asgari

Mehravaran

Fotouhi

et al. 2019

European Journal of Ophthalmology

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Purpose: To determine the total corneal refractive power in 1–8 mm corneal zones and the 8 mm Q-value in non-keratoconic patients with Down syndrome and normal subjects aged 10–30 years. Methods: Right eye data from 203 Down syndrome patients (mean ± standard deviation age: 17.0 ± 4.7 years) and 189 age- and gender-matched normal subjects (17.1 ± 4.5 years) were compared. Main extracted Pentacam indices were total corneal refractive power in steep and flat axes, and mean and difference (corneal astigmatism) total corneal refractive power in 1–8 mm zones. Results: Mean total corneal refractive power in 1–8 mm zones was 45.17–45.74 D and 42.91–43.52 D in Down and normal group, respectively (all p < 0.001). The coefficients of variation of total corneal refractive power from the center to the periphery were similar in the two groups (p = 0.855). None of the mean total corneal refractive powers significantly correlated with age, and all of them were significantly higher in females (p < 0.001). Mean total corneal refractive power–based corneal astigmatism in these zones changed from 1.46 to 1.66 D in Down syndrome patients and 1.64 to 1.99 D in normal group. All corneal astigmatism indices were similar between two groups (all p > 0.05). The prevalence of against the rule and oblique astigmatism in all zones were higher in the Down syndrome group (all p < 0.05). Conclusion: Adolescent and young non-keratoconic patients with Down syndrome have a more prolate cornea and a homogeneous keratometry distribution. In this population, females have a steeper cornea.

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Section: Discussionsupporting

confidence: 93%

Total corneal refractive power and shape in Down syndrome

Asgari

Mehravaran

Fotouhi

et al. 2019

European Journal of Ophthalmology

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“…In the present multicenter study, we found a mean PCA of 0.34 ± 0.14 D with a range of 0.00 D-0.99 D in Chinese myopic patients having corneal refractive surgery. The result was consistent with previous studies showing a mean PCA of 0.24 D-0.37 D in healthy eyes from subjects of the similar ages 9,15,16,24 . In our study, PCA ≥ 0.50 D was found in 11.61% of the eyes.…”

Section: Discussionsupporting

confidence: 93%

“…There have been several reports about PCA pattern in patients having assessment for refractive surgery or in patients about the same age 9,15,16 . However, results from these reports may not be directly applied to our patients since there may be significant differences in posterior corneal metrics among different ethnic groups 17 .…”

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confidence: 99%

A multicenter study of the distribution pattern of posterior corneal astigmatism in Chinese myopic patients having corneal refractive surgery

Zhu²,

Xiong³

et al. 2020

Sci Rep

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Including posterior corneal astigmatism (PCA) into consideration may increase the accuracy of astigmatism correction after corneal refractive surgery. In the present study we aim to investigate the distribution pattern of PCA in a large number of myopic patients from multiple ophthalmic centers. There were 7829 eyes retrospectively included in the study. Pentacam data of the eyes were retrieved from the machine and only results with image quality labelled with ‘OK’ were included. Distribution of PCA was slightly positively skewed (Skewness = 0.419, Kurtosis = 0.435, KS P < 0.0001). Mean PCA was 0.34 ± 0.14 D (range: 0.00 D-0.99 D). PCA was ≥ 0.25 D in 74.91% of the eyes and was ≥ 0.50 D in 11.61% of the eyes. In 97.55% of the eyes the steep meridian of PCA was vertical (SMV). PCA magnitude was significantly higher in eyes with SMV PCA (P < 0.0001) or high manifest astigmatism (MA, P < 0.0001). There was a significant correlation between anterior corneal astigmatism (ACA) magnitude and PCA magnitude in all of the eyes (r = 0.704, P < 0.0001). There was also a trend of decreasing frequency and magnitude of SMV PCA with aging (both P < 0.0001). In conclusion, PCA is present in myopic patients having corneal refractive surgery and PCA magnitude is increased with higher MA or ACA. Consideration of the impact of PCA on laser astigmatism correction may be necessary.

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“…This may be partly explained by the fact that the hyperopic group was significantly older than the myopic group and, therefore, may have underwent natural change of the astigmatism vector toward against-the-rule as corneas and associated refraction tend to shift from with-the-rule to against-the rule while aging. 17 In the current study, an association between age and corneal thickness was non-existent for myopes and negligible for hyperopes. Conflicting reports have been published regarding the association between age and corneal thickness with thinning of the cornea at a rate of up to 7 μm per decade being been reported by some groups, [18][19][20][21] and others reporting no such association.…”

Section: Discussioncontrasting

confidence: 51%

Correlation between refractive state, corneal thickness, and keratometry in ametropic patients

Rosenblatt

Sela

Munzer

et al. 2019

European Journal of Ophthalmology

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Purpose: To analyze the correlation between age, gender, refractive error, keratometry, and corneal thickness in a large group of subjects. Methods: This study is a retrospective analysis of patients who underwent refractive surgery between January 2000 and February 2015 at Care Vision Refractive Clinic, Tel Aviv, Israel. Patient demographics, subjective refraction, pachymetry, and average keratometry were collected. Results: Overall, 51,113 eyes of patients averaging 28.8 ± 9.3 years of which 53.9% were males were included. Average keratometry, spherical equivalent and cylindrical error differed significantly between male and female subjects (p < 0.001), while pachymetry did not (p = 0.332). In myopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between age and either pachymetry (p = 0.462) or spherical equivalent (p = 0.016). All correlations found were negligible or small (|r|= 0.003 to 0.141). In hyperopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between average keratometry and either pachymetry or cylindrical error (p = 0.344 or p = 0.274, respectively). All correlations found were negligible or small, except for a moderate correlation found between age and cylindrical error (r = 0.365). Conclusion: Refractive state, pachymetry, and keratometry of refractive surgery candidates are mostly weakly correlated.

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Age‐related changes in with‐the‐rule and oblique corneal astigmatism

Cited by 34 publications

References 26 publications

Total corneal refractive power and shape in Down syndrome

Total corneal refractive power and shape in Down syndrome

A multicenter study of the distribution pattern of posterior corneal astigmatism in Chinese myopic patients having corneal refractive surgery

Correlation between refractive state, corneal thickness, and keratometry in ametropic patients

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