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Hayashi K, Uno K, Manabe SI, Yoshimura K. Age-Related Changes in Total Corneal Astigmatism in Eyes With High Myopia. Cornea 2023:00003226-990000000-00432. [PMID: 38049154 DOI: 10.1097/ico.0000000000003447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/26/2023] [Indexed: 12/06/2023]
Abstract
PURPOSE The purpose of this study was to compare age-related changes in corneal astigmatism in eyes with and without high myopia. METHODS Eight-hundred eyes with high myopia (axial length ≥26.0 mm) and 800 eyes without high myopia (200 eyes each from patients in their 40s, 50s, 60s, and ≥70s) underwent videokeratographic examination. The amounts of vertical/horizontal (Rx) and oblique astigmatism (Ry) components, irregular astigmatism, and corneal shape were compared between eyes with and without high myopia and among age categories. RESULTS In both groups, the mean Rx significantly changed to more positive with age (P < 0.001), whereas the Ry did not change significantly. The Rx was significantly more negative in the high myopia group than in the control group in all age categories (P ≤ 0.003), whereas the Ry did not differ significantly. The mean changes in the Rx and Ry during each 2 consecutive decades did not differ significantly between groups. The asymmetry and higher-order irregularity components increased with age (P ≤ 0.001) but did not differ significantly between groups, except for the higher-order irregularity in patients in their 60s (P = 0.018). In the averaged map, the corneal shape changed from with-the-rule to against-the-rule astigmatism with age in both groups, but the changes occurred later in the high myopia group. CONCLUSIONS Age-related changes from with-the-rule to against-the-rule astigmatism occurred later in eyes with high myopia compared with eyes without high myopia in middle or older aged patients, but this change in each age decade was comparable between eyes with and without high myopia.
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Corneal and Whole-Eye Higher Order Aberrations Do Not Correlate With Ocular Residual Astigmatism in Prepresbyopic Refractive Surgery Candidates. Cornea 2022:00003226-990000000-00167. [PMID: 36730015 DOI: 10.1097/ico.0000000000003160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 08/18/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE Ocular residual astigmatism (ORA) is the proportion of manifest astigmatism that is not explained by anterior corneal astigmatism. The role of higher order aberrations (HOAs) in the level of ORA has not been profoundly studied. The purpose of this study was to evaluate the effect of different corneal and whole-eye HOAs on levels of ORA using a multivariate modeling approach. METHODS This is a retrospective analytical study including a sample of healthy refractive surgery candidates. One eye of every patient was randomly selected. A total of 294 eyes from an equal number of patients were included. Corneal and whole-eye HOAs were measured with a Pentacam AXL Wave, and subjective manifest refraction was taken. Astigmatism values were converted into power vectors and ORA was calculated. The Spearman rank-order correlation was initially used to explore correlation between HOA and ORA. All variables with a P value under 0.10 were included into a multiple linear regression model to explore this correlation adjusting for confounding variables. RESULTS The mean age was 28.81 ± 5.40 years. Simple bivariate correlation was significant for root mean square (RMS) total, RMS lower order aberrations, RMS HOAs, defocus, and vertical astigmatism. After being included into a multivariate regression model adjusting for confounding variables, the only variable that was significant was RMS total [F(3, 282) = 78.977; P < 0.001; adjusted R2 = 0.451]. For every μm increase in corneal RMS total, ORA increases by 0.135 diopters. About 45% of variability in ORA can be explained by corneal RMS total, corneal J0, and manifest J0. No individual HOA correlated with ORA in the multivariate regression model. CONCLUSIONS ORA increases with general corneal irregularity, especially regular astigmatism. Irregular astigmatism expressed by corneal and whole-eye HOAs does not seem to be a significant contributor of ORA in healthy refractive surgery candidates.
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Heydarian S, Sardari S, Heidari Z, Yekta AA, Ostadimoghaddam H, Khabazkhoob M. Corneal and Ocular Residual Astigmatism in School-Age Children. J Curr Ophthalmol 2021; 32:355-360. [PMID: 33553837 PMCID: PMC7861098 DOI: 10.4103/joco.joco_8_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 04/08/2020] [Accepted: 04/21/2020] [Indexed: 11/04/2022] Open
Abstract
Purpose To determine the distribution of residual and corneal astigmatism (CA) in children aged 6-18 years and their relationship with age, sex, spherical equivalent, and biometric parameters. Methods In this cross-sectional study, multi-stage stratified cluster sampling was done to select students from Dezful, a city in Southwestern Iran. Examinations included the measurement of visual acuity with and without optical correction, refraction with and without cycloplegia, and biometry using the Biograph (Lenstar, Germany). The main outcomes in this report were corneal and residual astigmatism. The CA was measured by Biograph (difference between k1 and k2), and residual astigmatism was calculated using Alpine method. The power vector method was applied to analyze the data of astigmatism. Results Of 864 students that were selected, 683 (79.1%) participated in the study. The mean residual and CA were -0.84 diopter (D) and -0.85 D, respectively. According to the results of J0 and J45 vectors, residual astigmatism was -0.33 D and 0.04 D, and CA was 0.38 D and 0.01 D, respectively. With-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism were seen in 3.4%, 66.8%, and 4.5% of the children with residual astigmatism and 67.94%, 1.3%, and 1.5% of the children with CA. Residual astigmatism decreased with an increase in spherical refractive error, whereas CA increased with an increase in spherical refractive error. Conclusion The results of the present study showed a high prevalence and amount of residual astigmatism with ATR pattern among the 6-18-year-old population and the compensatory effect of this type of astigmatism on CA that mostly followed a WTR pattern.
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Affiliation(s)
- Samira Heydarian
- Department of Rehabilitation Science, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sara Sardari
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Zahra Heidari
- Department of Rehabilitation Science, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran.,Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Abbas Ali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Mohammadi SF, Khorrami-Nejad M, Hamidirad M. Posterior corneal astigmatism: a review article. CLINICAL OPTOMETRY 2019; 11:85-96. [PMID: 31496856 PMCID: PMC6697663 DOI: 10.2147/opto.s210721] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/29/2019] [Indexed: 05/15/2023]
Abstract
Most human eyes show at least a small degree of corneal astigmatism and it can arise from both surfaces of the cornea. The shape of the anterior corneal surface provides no definitive basis for knowing the toricity of the posterior surface. In the previous studies, average astigmatism of the posterior corneal surface was -0.26 to -0.78 diopter. The radius of the posterior corneal surface is less than the radius of the anterior corneal surface. Most studies have found a clear correlation between the anterior and posterior corneal asphericities and the asphericity of the posterior surface is independent of the vertex radius of curvature, refractive error and gender. In contrast to the anterior corneal surface, the asphericity of the posterior corneal surface varies significantly between meridians. The anterior and posterior corneal surface would have approximately parallel principal meridians and both of these surfaces are often flatter in the horizontal meridian than the vertical one. This is especially true in the higher degrees of corneal astigmatism, and then about 10% of any anterior corneal astigmatism is neutralized by an astigmatism arising from the posterior corneal surface. Although the second corneal surface only contributes to about 10% of the total refractive power of the eye, a precise knowledge of its morphology is needed for the correct diagnosis and monitoring the corneal diseases or the surgical interventions and in many eyes neglecting the posterior corneal surface measurement may lead to significant deviations from the corneal astigmatism estimation. In this article, we have reviewed the shape and the toricity of the posterior corneal surface and also the effect of age on it. We investigated the contribution of posterior corneal astigmatism to the total corneal astigmatism and evaluated the accuracy of corneal astigmatism estimation by neglecting the posterior corneal surface measurement.
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Affiliation(s)
- Seyed-Farzad Mohammadi
- Translational Ophthalmology Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences
, Tehran, Iran
| | - Masoud Khorrami-Nejad
- Translational Ophthalmology Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences
, Tehran, Iran
- School of Rehabilitation, Shahid Beheshti University of Medical Sciences
, Tehran, Iran
| | - Moein Hamidirad
- School of Rehabilitation, Shahid Beheshti University of Medical Sciences
, Tehran, Iran
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Global and regional estimates of prevalence of refractive errors: Systematic review and meta-analysis. J Curr Ophthalmol 2017; 30:3-22. [PMID: 29564404 PMCID: PMC5859285 DOI: 10.1016/j.joco.2017.08.009] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 08/01/2017] [Accepted: 08/24/2017] [Indexed: 11/22/2022] Open
Abstract
Purpose The aim of the study was a systematic review of refractive errors across the world according to the WHO regions. Methods To extract articles on the prevalence of refractive errors for this meta-analysis, international databases were searched from 1990 to 2016. The results of the retrieved studies were merged using a random effect model and reported as estimated pool prevalence (EPP) with 95% confidence interval (CI). Results In children, the EPP of myopia, hyperopia, and astigmatism was 11.7% (95% CI: 10.5–13.0), 4.6% (95% CI: 3.9–5.2), and 14.9% (95% CI: 12.7–17.1), respectively. The EPP of myopia ranged from 4.9% (95% CI: 1.6–8.1) in South–East Asia to 18.2% (95% CI: 10.9–25.5) in the Western Pacific region, the EPP of hyperopia ranged from 2.2% (95% CI: 1.2–3.3) in South-East Asia to 14.3% (95% CI: 13.4–15.2) in the Americas, and the EPP of astigmatism ranged from 9.8% in South-East Asia to 27.2% in the Americas. In adults, the EPP of myopia, hyperopia, and astigmatism was 26.5% (95% CI: 23.4–29.6), 30.9% (95% CI: 26.2–35.6), and 40.4% (95% CI: 34.3–46.6), respectively. The EPP of myopia ranged from 16.2% (95% CI: 15.6–16.8) in the Americas to 32.9% (95% CI: 25.1–40.7) in South-East Asia, the EPP of hyperopia ranged from 23.1% (95% CI: 6.1%–40.2%) in Europe to 38.6% (95% CI: 22.4–54.8) in Africa and 37.2% (95% CI: 25.3–49) in the Americas, and the EPP of astigmatism ranged from 11.4% (95% CI: 2.1–20.7) in Africa to 45.6% (95% CI: 44.1–47.1) in the Americas and 44.8% (95% CI: 36.6–53.1) in South-East Asia. The results of meta-regression showed that the prevalence of myopia increased from 1993 (10.4%) to 2016 (34.2%) (P = 0.097). Conclusion This report showed that astigmatism was the most common refractive errors in children and adults followed by hyperopia and myopia. The highest prevalence of myopia and astigmatism was seen in South-East Asian adults. The highest prevalence of hyperopia in children and adults was seen in the Americas.
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Peyman A, Dastborhan Z, Peyman M. Astigmatic treatment with photorefractive keratectomy: Investigations of non-keratometric ocular astigmatism. J Curr Ophthalmol 2017; 29:98-102. [PMID: 28626818 PMCID: PMC5463002 DOI: 10.1016/j.joco.2016.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/28/2016] [Accepted: 12/06/2016] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To evaluate the effect of non-keratometric ocular astigmatisms on visual and refractive outcomes after photorefractive keratectomy (PRK) for correction of myopic astigmatisms. METHODS Seventy one eyes of 36 subjects were enrolled in this study. Patients underwent PRK for treatment of myopia. Subjects were evaluated for refractive error, keratometry, and visual acuity before and six months after surgery. Pre- and post-op non-keratometric astigmatisms were calculated by vectorial analysis of the difference between the corneal plane refractive astigmatism and keratometric astigmatism. Astigmatic analysis explored the contribution of non-keratometric astigmatisms. RESULTS The pre-op spherical equivalent (SE) was -6.27 ± 1.48 with 1.16 ± 1.02 diopters of corneal plane refractive astigmatism and 1.44 ± 0.47 diopters keratometric astigmatism. Post-op values were -0.60 ± 0.85, 0.56 ± 0.47, and 1.06 ± 0.57, respectively, 6 months after surgery. Pre- and post-op non-keratometric astigmatisms were 0.76 ± 0.41 and 0.76 ± 0.46, respectively, (P = 0.976) with significant correlation (r = 0.37, P = 0.002). Pre-op non-keratometric astigmatisms correlated to the pre-op SE (r = -0.25, P = 0.04). Pre-op non-keratometric astigmatisms had significant correlation with keratometric difference vector of astigmatic correction (r = 0.369, P = 0.002). Post-op non-keratometric astigmatisms correlated to keratometric induced astigmatism (r = 0.334, P = 0.006), keratometric index of success (r = 0.571, P < 0.001), and post-op keratometric astigmatism (r = 0.736, P < 0.001). CONCLUSIONS Higher or lower non-keratometric ocular astigmatisms did not have any effect on refractive and visual outcome after PRK. PRK effectively corrected total refractive astigmatism through correction of keratometric astigmatism and additional adjustment to compensate for non-keratometric ocular astigmatisms.
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Affiliation(s)
- Alireza Peyman
- Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zahra Dastborhan
- Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Peyman
- Department of Ophthalmology, Faculty of Medicine Building, University of Malaya, Kuala Lumpur, Malaysia
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Abstract
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 to 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 ± 1.47 years), 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 (χ p < 0.001). When matched by CA, compensation remained poorer in myopes than non-myopes (χ all p ≤ 0.04). Within each refractive group, compensation was better when CA was low than high (χ 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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Mohammadpour M, Heidari Z, Khabazkhoob M, Amouzegar A, Hashemi H. Correlation of major components of ocular astigmatism in myopic patients. Cont Lens Anterior Eye 2015; 39:20-5. [PMID: 26187142 DOI: 10.1016/j.clae.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 05/30/2015] [Accepted: 06/29/2015] [Indexed: 11/19/2022]
Abstract
PURPOSE To investigate the correlation of major components of ocular astigmatism in myopic patients in an academic hospital. METHODS This cross-sectional study was conducted on 376 eyes of 188 patients who were referred to Farabi Eye Hospital for refractive surgery. Preoperative examinations including refraction and corneal topography were performed for all candidates to measure refractive and corneal astigmatism. Ocular residual astigmatism was calculated using vector analysis. Pearson's correlation and ANOVA analysis were used to evaluate the strength of the association between different types of astigmatism. Both eyes were defined as cluster and the Generalized Estimating Equations (GEE) analysis were performed. RESULTS Mean age of 119 women (63.3%) and 69 men (36.7%) was 27.8 ± 5.7 years. Mean refractive error based on spherical equivalent was -3.59 ± 1.95D (range, -0.54 to -10.22D). Mean refractive and corneal astigmatism was 1.97 ± 1.3D and 1.85 ± 1.01D, respectively. Mean amount of ORA was 0.65 ± 0.36D.There was a significant correlation between ORA and refractive astigmatism(r=0.23, p<0.001), corneal and refractive astigmatism (r=0.91, p<0.001) and a weak correlation between ORA and corneal astigmatism (r=0.13, p=0.014). There was a significant correlation between J0 and J45 values of ORA and corneal astigmatism (p<0.001). CONCLUSION There is a significant correlation between ORA and refractive astigmatism, refractive and corneal astigmatism and a weak correlation between ORA and corneal astigmatism in refractive surgery candidates. Identifying the type of astigmatism and preoperative measurement of ocular residual astigmatism is highly recommended prior to any refractive surgery, especially in cases with significant astigmatism.
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Affiliation(s)
- Mehrdad Mohammadpour
- Associate Professor of Ophthalmology, Farabi Eye Hospital, Ophthalmology Department and Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Heidari
- Researcher, Farabi Eye Hospital, Ophthalmology Department and Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mehdi Khabazkhoob
- Department of epidemiology, Faculty of health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Afsaneh Amouzegar
- Farabi Eye Hospital, Ophthalmology Department and Eye Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Professor of Ophthalmology, Noor Eye Hospital, Noor Ophthalmology Research Center, Tehran, Iran
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Pärssinen O, Kauppinen M, Viljanen A. Astigmatism among myopics and its changes from childhood to adult age: a 23-year follow-up study. Acta Ophthalmol 2015; 93:276-83. [PMID: 25384542 DOI: 10.1111/aos.12572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/07/2014] [Indexed: 12/18/2022]
Abstract
PURPOSE To study the prevalence of and changes in astigmatism from the onset of myopia at school age. METHODS Two hundred and forty myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983-1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Three annual examinations with subjective cycloplegic refraction were performed for 237-238 subjects. Subsequent examinations were performed at the mean ages of 23.2 and 33.9 years for 178 and 163 subjects, and the last examination, including data from prescriptions of different ophthalmologists, for 32 subjects. Corneal topography was studied at baseline, at the 3-year follow-up and at the two adulthood follow-ups. Prevalence and changes in refractive astigmatism (RA), in its polar values J0 and J45, and corneal astigmatism (CA) were studied. RESULTS Mean RA of the right eye increased during follow-up from 0.26 D (SD) ± 0.30 to 0.79 D ± 0.74. Mean CA was 1.07 D ± 0.74 at study end. The prevalence of RA ≥0.25 or ≥1.00 D increased from 54.9 and 3.8% to 83.4 and 34.4%, respectively. The main direction of the axis of RA and its polar value J0 and CA changed mainly through sphericity, from against the rule (ATR) to with the rule during the follow-up. There was a negative correlation between RA and spherical refraction in the ATR group at end of follow-up. Changes in RA were associated with increase in myopia and with changes in CA. CONCLUSIONS The prevalence and mean amount of RA associated with CA increased, and the axis of astigmatism changed among myopics during the 23-year follow-up.
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Affiliation(s)
- Olavi Pärssinen
- Department of Ophthalmology Central Hospital of Central Finland Jyväskylä Finland
- Gerontology Research Center and Department of Health Sciences University of Jyväskylä Jyväskylä Finland
| | - Markku Kauppinen
- Gerontology Research Center and Department of Health Sciences University of Jyväskylä Jyväskylä Finland
| | - Anne Viljanen
- Gerontology Research Center and Department of Health Sciences University of Jyväskylä Jyväskylä Finland
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Roh HC, Chuck RS, Lee JK, Park CY. The effect of corneal irregularity on astigmatism measurement by automated versus ray tracing keratometry. Medicine (Baltimore) 2015; 94:e677. [PMID: 25837759 PMCID: PMC4554023 DOI: 10.1097/md.0000000000000677] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The aim of this study was to compare the effect of corneal irregularity on astigmatism assessment using automated keratometry (AK) (IOLMaster) versus ray tracing keratometry (Pentacam). This is an observational case series approved by the institutional review board of Dongguk University Hospital, Goyang, South Korea. A total of 207 eyes of 207 cataract patients were included. Preoperative corneal astigmatism was measured by both IOLMaster and Pentacam. Corneal irregularity index (IR) was calculated in Fourier analysis map of Pentacam. AK by IOLMaster and total corneal refractive power (TCRP, 3 mm and 4 mm zone analysis with pupil centered) by Pentacam were selected and the difference between the 2 measurements (delta Δ) was calculated using vector analysis. Ocular residual astigmatism (ORA) after cataract surgery was calculated by subtracting 6-month postoperative refractive astigmatism (RA) measurements from corresponding preoperative values (AK, TCRP3, and TCRP4). The mean irregularity index measured was 0.042 ± 0.019 mm (mean ± standard deviation) and was positively correlated with age and magnitude of corneal astigmatism (P < 0.001 and P < 0.05). The difference (Δ) between TCRPs and AK (ΔTCRPs-AK) was 0.43 ± 0.37 (TCRP3) and 0.39 ± 0.35 (TCRP4) diopters. Linear regression analysis revealed that age (P < 0.001), IR (P < 0.001), and AK (P < 0.001) were positively correlated with ΔTCRPs-AK. In highly irregular corneas (IR over 0.77 diopters: mean + 2 standard deviation), postoperative ORAs calculated using TCRPs were significantly lower than ORAs calculated using AK. Corneal irregularities significantly impact astigmatism assessment by IOLMaster (AK) and Pentacam (TCRPs). Compared with AK, TCRPs were more accurate in predicting postoperative residual astigmatism in highly irregular corneas.
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Affiliation(s)
- Hyun Cheol Roh
- From the Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, Kyunggido, South Korea (HCR, CYP); and Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA (RSC, JKL)
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Koh V, Yang A, Saw SM, Chan YH, Lin ST, Tan MMH, Tey F, Nah G, Ikram MK. Differences in Prevalence of Refractive Errors in Young Asian Males in Singapore between 1996–1997 and 2009–2010. Ophthalmic Epidemiol 2014; 21:247-55. [DOI: 10.3109/09286586.2014.928824] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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