Evaluation of the Repeatability and the Reproducibility of AL-Scan Measurements Obtained by Residents

Purpose. To assess the repeatability and reproducibility of ocular biometry and intraocular lens (IOL) power measurements obtained by ophthalmology residents using an AL-Scan device, a novel optical biometer.Methods. Two ophthalmology residents were instructed regarding the AL-Scan device. Both performed ocular biometry and IOL power measurements using AL-Scan, three times on each of 128 eyes, independently of one another. Corneal keratometry readings, horizontal iris width, central corneal thickness, anterior chamber depth, pupil size, and axial length values measured by both residents were recorded together with IOL power values calculated on the basis of four different IOL calculation formulas (SRK/T, Holladay, and HofferQ). Repeatability and reproducibility of the measurements obtained were analyzed using the intraclass correlation coefficient (ICC).Results. Repeatability (ICC, 0.872-0.999 for resident 1 versus 0.905-0.999 for resident 2) and reproducibility (ICC, 0.916-0.999) were high for all biometric measurements. Repeatability (ICC, 0.981-0.983 for resident 1 versus 0.995-0.996 for resident 2) and reproducibility were also high for all IOL power measurements (ICC, 0.996 for all).Conclusions. The AL-Scan device exhibits good repeatability and reproducibility in all biometric measurements and IOL power calculations, independent of the operator concerned.

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Precision of Corneal Thickness Measurements Obtained Using the Scheimpflug-Placido Imaging and Agreement with Ultrasound Pachymetry

Journal of Ophthalmology ◽

10.1155/2015/328798 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Jinhai Huang ◽

Giacomo Savini ◽

Chengfang Wang ◽

Weicong Lu ◽

Rongrong Gao ◽

...

Keyword(s):

Healthy Subjects ◽

Corneal Thickness ◽

Intraclass Correlation ◽

Normal Subjects ◽

Limits Of Agreement ◽

Ultrasound Pachymetry ◽

Good Repeatability ◽

Repeatability And Reproducibility ◽

The Mean ◽

Thickness Measurements

Purpose.To assess the reliability and comparability of measuring central corneal thickness (CCT) and thinnest corneal thickness (TCT) using a new Scheimpflug-Placido analyzer (TMS-5, Japan) and ultrasound (US) pachymetry.Methods.Seventy-six healthy subjects were prospectively measured 3 times by 1 operator using the TMS-5, 3 additional consecutive scans were performed by a second operator, and ultrasound (US) pachymetry measurements were taken. The test-retest repeatability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were calculated to evaluate intraoperator repeatability and interoperator reproducibility. Agreement among the devices was assessed using Bland-Altman plots and 95% limits of agreement (LoA).Results.The intraoperators TRT and CoV were <19 μm and 2.0%, respectively. The interoperators TRT and CoV were <12 μm and 1.0%, respectively, and ICC was >0.90. The mean CCT and TCT measurements using the TMS-5 were 15.97 μm (95% LoA from −26.42 to −5.52 μm) and 20.32 μm (95% LoA from −30.67 to −9.97 μm) smaller, respectively, than those using US pachymetry.Conclusions.The TMS-5 shows good repeatability and reproducibility for measuring CCT and TCT in normal subjects but only moderate agreement with US pachymetry results. Caution is warranted before using these techniques interchangeably.

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Comparison of Anterior Ocular Biometric Measurements Using Swept-Source and Time-Domain Optical Coherence Tomography

Journal of Ophthalmology ◽

10.1155/2020/9739878 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Sisi Chen ◽

Rongrong Gao ◽

Colm McAlinden ◽

Junming Ye ◽

Yiran Wang ◽

...

Keyword(s):

Time Domain ◽

Corneal Thickness ◽

Intraclass Correlation ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Correlation Coefficients ◽

Random Order ◽

Optical Coherence ◽

Swept Source ◽

Significant Difference

Purpose. To compare central corneal thickness (CCT), aqueous depth (AQD), and anterior chamber depth (ACD) measurements using the swept-source (CASIA SS-1000, Tomey, Japan) and time-domain (Visante, Carl Zeiss Meditec, USA) anterior segment optical coherence tomographers (OCT) in normal eyes. Methods. Sixty-eight eyes of 68 subjects were included. Three consecutive scans of each subject were obtained using both devices in a random order by one experienced operator. Standard deviation (Sw), coefficient of repeatability (CoR), coefficients of variation (CoV), and intraclass correlation coefficients (ICC) were used to evaluate the intraoperator repeatability. Agreement was assessed using the Bland–Altman plots and 95% limits of agreement (LoA). Results. All measurements of the swept-source OCT (SS-OCT) and time-domain OCT (TD-OCT) showed high repeatability with low CoR (CCT: 2.34 μm and 6.16 μm; AQD: 0.05 mm and 0.09 mm; ACD: 0.06 mm and 0.09 mm), low CoV (CCT: 0.16% and 0.42%; AQD: 0.61% and 0.97%; ACD: 0.53% and 0.83%), and high ICC (>0.98). The mean CCT with SS-OCT was slightly thicker than the results with TD-OCT (difference = 4.55 ± 2.62 μm, P<0.001). There was no statistically significant difference in AQD or ACD measurements between the two devices (0.01 ± 0.05 mm, P=0.111; 0.02 ± 0.05 mm, P=0.022, respectively). The 95% LoA between the SS-OCT and TD-OCT were −0.59 to 9.69 μm for CCT, −0.10 to 0.12 mm for AQD, and −0.09 to 0.12 mm for ACD. Conclusions. High levels of repeatability and agreement were found between the two devices for all three parameters, suggesting interchangeability. SS-OCT demonstrated superior repeatability compared with TD-OCT.

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Comparison of intraocular lens power calculation results before and after glaucoma surgery

Ophthalmology journal ◽

10.17816/ov42296 ◽

2020 ◽

Vol 13 (4) ◽

pp. 15-20

Author(s):

Dmitrii Fedorovich Belov ◽

Vadim Petrovich Nikolaenko

Keyword(s):

Intraocular Lens ◽

Anterior Chamber Depth ◽

Glaucoma Surgery ◽

Power Calculation ◽

Ahmed Glaucoma Valve ◽

Iol Power Calculation ◽

Iol Calculation ◽

Before And After ◽

Iol Power ◽

Target Refraction

Aim to compare intraocular lens (IOL) power calculation before and after different types glaucoma procedures. Material and methods.Into the study, 115 patients were included, divided into 3 groups: group 1 patients, in whom sinustrabeculectomy was performed (n= 86); group 2 patients with implanted Ex-PRESS shunt (n= 19), group 3 patients after Ahmed glaucoma valve implantation (n= 10). For each patient before surgery optical biometry (IOL-Master 500) was performed and IOL power calculation using Barrett Universal II Formula (target refraction emmetropia). Baseline data were compared with corresponding examinations results obtained in 6 months after glaucoma procedure, to evaluate its effect on main biometric parameters of the eye and the IOL calculation accuracy. Results.Despite significant changes of optical and anatomic indices, mean values of target refraction before and after glaucoma surgery did not differ significantly: 0.00 0.03 versus 0.03 0.52 D (p= 0.628), 0.00 0.1 versus 0.19 0.61 D (p= 0.173), 0.04 0.08 versus 0.11 0.42 D (p= 0.269) for groups, respectively. However, there was a pronounced trend to the increase of target refraction data scattering. Conclusion.Glaucoma procedures cause changes of biometrical parameters of the eye, which leads to decrease in accuracy of IOL calculation. Consequently, when choosing intraocular lens, it is recommended to use measurement results obtained after glaucoma surgery. Keywords:intraocular lens; IOL power calculation; glaucoma; sinustrabeculectomy; Ex-PRESS shunt; Ahmed glaucoma valve; biometry; phacoemulsification; axial length; anterior chamber depth; keratometry.

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Repeatability and reproducibility of corneal biomechanical parameters derived from Corvis ST

European Journal of Ophthalmology ◽

10.1177/1120672119864554 ◽

2019 ◽

Vol 30 (6) ◽

pp. 1287-1294

Author(s):

Nermin Serbecic ◽

Sven Beutelspacher ◽

Lovro Markovic ◽

Abhijit Sina Roy ◽

Rohit Shetty

Keyword(s):

Correlation Coefficient ◽

Intraclass Correlation Coefficient ◽

Coefficient Of Variation ◽

Intraclass Correlation ◽

Diurnal Changes ◽

Good Reliability ◽

Good Repeatability ◽

Repeatability And Reproducibility ◽

Biomechanical Parameters ◽

High Intraclass Correlation Coefficient

Introduction: The aim of this study was to evaluate repeatability and reproducibility of newly calculated biomechanical parameters of the cornea, developed by our research group. Methods: One eye from each of the 23 healthy subjects was measured three times consecutively, three times at different daytimes and on three different days. The within-subject standard deviation and coefficient of variation, as well as the intraclass correlation coefficient, were calculated for every parameter in each group. Results: Excellent repeatability and reproducibility (coefficient of variation < 5%, intraclass correlation coefficient > 0.75) was found for corrected values measured at A1, HC, and A2 time points (2nd A2 Time, 2nd A1 Time, 2nd HC Time, 2nd HC Def Amp and 2nd A1 Def Amp). Corneal-specific stiffness parameters, which showed good repeatability and reliability, were DA_cor (coefficient of variation = 4.02%, intraclass correlation coefficient = 0.919), KcLinear (coefficient of variation = 4.03%, intraclass correlation coefficient = 0.895), areaForceCornea (coefficient of variation = 3.34%, intraclass correlation coefficient = 0.853) and E2 (coefficient of variation = 4.1%, intraclass correlation coefficient = 0.78). Overall, most parameters fell into the category of good reliability (high intraclass correlation coefficient) and poor reproducibility (low coefficient of variation), including all the parameters describing extraocular deformation (DA_ext, AEPvED, AUC EDef, areaForceExtra, Kg and μg). Comparing the coefficient of variation values for intrasession, intersession and daytime measurements, there were no indices for diurnal changes. Conclusion: Most parameters showed good repeatability and reliability. The extraocular stiffness parameters showed poor reproducibility. KcLinear can serve as a very reliable and repeatable indicator of corneal stiffness.

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Comparison of Repeatability and Agreement between Swept-Source Optical Biometry and Dual-Scheimpflug Topography

Journal of Ophthalmology ◽

10.1155/2017/1516395 ◽

2017 ◽

Vol 2017 ◽

pp. 1-5 ◽

Cited By ~ 9

Author(s):

Soyeon Jung ◽

Hee Seung Chin ◽

Na Rae Kim ◽

Kang Won Lee ◽

Ji Won Jung

Keyword(s):

Prediction Error ◽

Central Corneal Thickness ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Swept Source ◽

Good Repeatability ◽

Optical Biometer ◽

Corneal Diameter ◽

High Repeatability ◽

Iolmaster 700

Purpose. To assess the repeatability and agreement of parameters obtained with two biometers and to compare the predictability. Methods. Biometry was performed on 101 eyes with cataract using the IOLMaster 700 and the Galilei G6. Three measurements were obtained per eye with each device, and repeatability was evaluated. The axial length (AL), anterior chamber depth (ACD), keratometry (K), white-to-white (WTW) corneal diameter, central corneal thickness (CCT), and lens thickness (LT) were measured and postoperative predictability was compared. Results. Measurements could not be obtained with the IOLMaster 700 in one eye and in seven eyes with the Galilei G6 due to dense cataract. Both the IOLMaster 700 and Galilei G6 showed good repeatability, although the IOLMaster 700 showed better repeatability than the Galilei G6. There were no statistically significant differences in AL, ACD, steepest K, WTW, and LT (P>0.050), although flattest K, mean K, and CCT differed (P<0.050). The proportion of eyes with an absolute prediction error within 0.5 D was 85.0% for the IOLMaster 700 and was 80.0% for the Galilei G6 based on the SRK/T formula. Conclusions. Two biometers showed high repeatability and relatively good agreements. The swept-source optical biometer demonstrated better repeatability, penetration, and an overall lower prediction error.

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Evaluation of the Relationships between Corneal Parameters, Ocular Biometry, and Myopia Magnitude

Sains Malaysiana ◽

10.17576/jsm-2021-5010-20 ◽

2021 ◽

Vol 50 (10) ◽

pp. 3077-3084

Author(s):

Mohd Izzuddin Hairol ◽

Norlaili Arif ◽

Pui Theng Yong ◽

Mariah Asem Shehadeh Saleh Ali ◽

Nik Nor Adlina Nik Idris ◽

...

Keyword(s):

Axial Length ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Radius Of Curvature ◽

Corneal Curvature ◽

Ocular Biometry ◽

Corneal Asphericity ◽

Corneal Radius ◽

The Difference ◽

The Relationship

Axial length of the eye correlates with the magnitude of myopia. However, there are conflicting reports on the relationship between certain corneal parameters with myopia magnitude. The objective of this study was to compare ocular biometry and corneal parameters between emmetropic and myopic groups. Participants (n=127) were categorized as emmetropia (spherical equivalent, SE, ±0.50D), low myopia (-0.75D≤SE<-6.00D) and high myopia (SE≥-6.00D). The difference in axial length, anterior chamber depth, and vitreous chamber depth between emmetrope, low myope, and high myope were highly significant (one-way ANOVA, all p<0.001) with significant correlations between SE and all these parameters (simple regressions, all p<0.001). However, central corneal thickness, corneal radius of curvature, and corneal asphericity between these groups, and the correlations between the ocular parameters with SE were not significantly different (all p>0.05). Corneal curvature correlated significantly with axial length (p=0.001) but not with myopia magnitude (p=0.91). Rather than myopia magnitude, axial length appears to be more sensitive to detect changes in corneal curvature in myopes. In conclusion, myopic patients’ axial length should be carefully considered for interventions that involve the cornea, such as orthokeratology and refractive surgery.

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Preoperative Anatomy Parameters in Implantable Collamer Lenses

10.21203/rs.3.rs-968382/v1 ◽

2021 ◽

Author(s):

Yanzhen Xue ◽

Yonghong Guo ◽

Ruibo Zhao

Keyword(s):

Regression Analysis ◽

Linear Regression ◽

Anterior Chamber ◽

Linear Regression Analysis ◽

Corneal Thickness ◽

Intraclass Correlation ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Case Series ◽

Significant Difference

Abstract Purpose: To determine patient preoperative anatomical features and the parameters of implantable collamer lenses (ICLs) relevant in explaining vault variability.Setting: Ophthalmology Xi’an Aier Gucheng Eye hospital , Xi’an China.Design: Retrospective case series.Methods:This study comprised 88 eyes of 45 patients implanted with myopic or toric ICLs between May 2021 and August 2021.Pentacam imaging was used for assessing white-to-white (WTW) diameter, central keratometry, anterior chamber depth(ACD), central corneal thickness and vault. Anterior-segment optical coherence tomography（AS-OCT） was used to measure the horizontal anterior chamber angle distance (ATA). Ultrasound biomicroscopy (UBM) was used to measure horizontal and vertical sulcus to sulcus(vSTS). According to different ACD,we divide ACD into shallow group(2.8 to 3.2 mm),medium group(3.2 to 3.5 mm),and deep group(＞3.5mm).Results: Linear regression analysis found significant correlation between WTW diameters and ATA diameters( y= 0.9605x+0.1491,R² = 0.9148),with a coefficient of determinant of 0.9148 (P＜0.01). Linear regression analysis found significant correlation between hSTS and vSTS（y=0.9855x-0.0178,R²=0.1979）,with a coefficient of determinant of 0.1979 (P＜0.01). WTW diameters showed statistically significant difference in shallow and medium ACD (t=-3.28,P＜0.01 ), significant difference in shallow and deep ACD (t=-4.69,P＜0.01 ),there was no correlation in medium and deep ACD(t=-1.41,P＞0.05 ). There was a statistically significant correlation between WTW diameters and hSTS diameters when the ACD was less than 3.5 mm (t=-0.451, P=0.000) (t=1.406, P=0.026),but weak correlation when the ACD was bigger than 3.5 mm(t=1.594, P=0.051). ATA and WTW with a mean difference close to zero(-0.66 mm). Despite the relatively high correlation (intraclass correlation co-efficient =0.689), the range of agreement is quite broad (1.33 mm).Conclusions:ATA measured with AS-OCT can not be used interchangeably with WTW obtained with Pentacam. WTW diameters and hSTS diameters have a statistically significant correlation when the ACD was less than 3.5 mm. WTW, ATA, hSTS and vSTS all should be considered during design the size of lens and regulating the vault after surgery.

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Comparison of the influence of pupil dilation on predicted postoperative refraction and recommended intraocular lens power among Barrett Universal II, Haigis, and SRK/T calculation formulas: a retrospective study

10.21203/rs.2.17071/v1 ◽

2019 ◽

Author(s):

Takeshi Teshigawara ◽

Akira Meguro ◽

Nobuhisa Mizuki

Keyword(s):

Retrospective Study ◽

Intraocular Lens ◽

Significant Positive Correlation ◽

Anterior Chamber Depth ◽

Pupil Dilation ◽

Power Calculation ◽

Positive Correlation ◽

Iol Calculation ◽

Before And After ◽

Iol Power

Abstract Background We investigated the effect of pupil dilation on predicted postoperative refraction (PPR) and recommended intraocular lens (IOL) power calculated using three different generations of IOL power calculation formulas: Barrett Universal II (Barrett) (new generation), Haigis (4th generation), and SRK/T (3rd generation).Methods This retrospective study included 150 eyes. The following variables were measured and calculated using an optical biometer before and after dilation: anterior chamber depth (ACD), lens thickness (LT), white-to-white (WTW), mean absolute change (MAC) in PPR, and recommended IOL power. PPR and recommended IOL power were calculated by Barrett, Haigis, and SRK/T IOL calculation formulas. Correlations between all changes were analyzed. The influence of pupil dilation on recommended IOL power calculated by each formula was also analyzed.Results MAC in PPR before and after dilation was highest in Barrett, followed by Haigis and SRK/T. Significant differences were found among each MAC. Significant changes were observed before and after dilation in ACD and LT but not in WTW. In Barrett and Haigis, there was a significant positive correlation between change in PPR and change in ACD and a negative correlation between change in PPR and change in LT. Correlations were strongest in Barret followed by Haigis, especially in LT. Change in PPR in Barrett also demonstrated a significant positive correlation with change in WTW. The recommended IOL power using Barrett and Haigis changed before and after dilation in 23.3% and 19.3% cases; SRK/T showed no change.Conclusions In PPR and recommended IOL power, pupil dilation influenced Barrett most strongly, followed by Haigis and SRK/T. Given the stronger correlation between the change in PPR in Barrett and the change in ACD, LT, and WTW, the change of ACD, LT, and WTW is more important to the influence of dilation on Barrett. The influence of dilation on each formula and variables, including ACD, LT, and WTW is key to improving IOL calculation.

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Repeatability and reproducibility of horizontal corneal diameter and anterior corneal power measurements using the Oculus Keratograph 4

African Vision and Eye Health ◽

10.4102/aveh.v75i1.350 ◽

2016 ◽

Vol 75 (1) ◽

Author(s):

Khathutshelo P. Mashige

Keyword(s):

Normal Vision ◽

Intra Class Correlation ◽

Corneal Power ◽

Good Repeatability ◽

Repeatability And Reproducibility ◽

The Right ◽

Power Measurements ◽

Intra Class Correlation Coefficient ◽

Corneal Diameter

Purpose: To evaluate the repeatability and reproducibility of horizontal corneal diameter (HCD) and anterior corneal power (ACP) measurements obtained with the Oculus Keratograph 4 (OCULUS Optikgeräte GmbH).Methods: These parameters (HCD and ACP) were prospectively measured in quick succession three times in each of the right eyes of 40 healthy subjects, aged 18–28 years, with normal vision (6/6 or better visual acuity) in the first session by a single examiner. Measurements were then repeated in the second session scheduled 1 week later by the same examiner using the same instrument. Repeatability and reproducibility of HCD and ACP measurements was assessed based on the intra-session and intersession within-subject standard deviation (sw), repeatability (2.77sw), coefficient of variation (CoV) and intra-class correlation coefficient (ICC).Results: Intra-session repeatability and intersession reproducibility of all measured parameters showed a repeatability (2.77sw) of 0.35 mm or less for HCD and 0.35 D or less for ACP, a CoV of 0.30% or less and an ICC of more than 0.9.Conclusion: HCD and ACP measurements obtained using an Oculus Keratograph 4 show good repeatability and reproducibility in healthy eyes; therefore, these parameters can be used for longitudinal follow-up when measured with this device.

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Comparison of Optical versus Ultrasonic Biometry in Keratoconic Eyes

Journal of Ophthalmology ◽

10.1155/2013/481238 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Yasin Çınar ◽

Abdullah Kürşat Cingü ◽

Muhammed Şahin ◽

Alparslan Şahin ◽

Harun Yüksel ◽

...

Keyword(s):

Central Corneal Thickness ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Demographic Characteristics ◽

Ophthalmological Examination ◽

Average Difference ◽

Bland Altman Method ◽

Study Population ◽

Biometric Measurements ◽

The Difference

Purpose. To compare the measurements of optical versus ultrasonic biometry devices in keratoconic eyes.Materials and Methods. Forty-two eyes of 42 keratoconus (KC) patients enrolled in the study were examined. Clinical and demographic characteristics of the patients were noted, and detailed ophthalmological examination was performed. Following Pentacam measurements, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were obtained using the Lenstar and US biometer to determine the reproducibility of the measurements between the two devices in keratoconic eyes. The Bland-Altman method was used to describe the agreement between the two devices.Results. The Lenstar could not measure at least one of the biometric properties in one eye and did not automatically give the corrected ACD in 2/3 of our study population. The Lenstar measured CCT (average difference 5.4 ± 19.6 µm; ICC = 0.90; ), LT (average difference 0.13 ± 0.17 mm; ICC = 0.67; ), and AL (average difference 0.10 ± 0.76 mm; ICC = 0.75; ) thinner than US biometer, whereas it measured ACD (average difference 0.18 ± 0.17 mm; ICC = 0.85; ) deeper than US biometer in keratoconic eyes.Conclusion. Although the difference between the measurements obtained using the two devices might be clinically acceptable, US biometry and Lenstar should not be used interchangeably for biometric measurements in KC patients.

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