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Purpose: To compare the biometric measurements obtained from the Pentacam AXL Wave, IOLMaster 700, and ANTERION and calculate the recommended intraocular lens power using the Barrett Formulae., Methods: This was a retrospective cross-sectional study of patients who underwent biometry using the Pentacam AXL Wave, IOLMaster 700, and ANTERION. Flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), and axial length (AL) from each device were measured and compared. These parameters were used to calculate the recommended IOL powers using the Barrett formula., Results: The study included 252 eyes of 153 patients. The IOLMaster had the highest acquisition rate among the two biometers. The Pentacam obtained the shortest mean AL, the IOLMaster measured the highest mean keratometry values, and the ANTERION measured the highest mean ACD. In terms of pairwise comparisons, keratometry and axial length were not significantly different between the Pentacam-IOLMaster and ANTERION-IOLMaster groups, while the rest of the pairwise comparisons were statistically significant. In nontoric and toric eyes, 35-45% of patients recommended the same sphere of IOL power. In another 30-40%, the Pentacam and ANTERION recommended an IOL power one step greater than that of the IOLMaster-derived data. 50% of the study population recommended the same toric-cylinder IOL power., Conclusions: The Pentacam AXL Wave, IOLMaster 700, and ANTERION can reliably provide data for IOL power calculations; however, these data are not interchangeable. In nontoric and toric eyes, 35-45% of cases recommended the same sphere IOL power, and in another 30-40%, the Pentacam and ANTERION recommended one-step higher IOL power than the IOLMaster-derived data. In targeting emmetropia, selecting the first plus IOL power is advisable when using the Pentacam and ANTERION to approximate the IOL power calculations recommended by the IOLMaster 700., (© 2024. The Author(s).)

We investigated a commercial low-coherence interferometer (LenStar LS 900 optical biometer) in measuring young rhesus monkey ocular dimensions. Ocular biometry data obtained using a LenStar and an A-scan ultrasound instrument (OPT-scan 1000) from 163 rhesus monkeys during 20-348 days of age were compared by means of coefficients of concordance and 95% limits of agreement. Linear regression was employed to examine and analyze the inter-instrument discrepancies. In young rhesus monkeys, the test-retest reliability of the LenStar was equal to or exceeded that of A-scan ultrasound (intraclass correlation = 0.86 to 0.93). The inter-instrument agreement was strong for vitreous chamber depth and axial length (coefficient of concordance = 0.95 and 0.86, respectively) and moderate for anterior chamber depth and lens thickness (coefficient of concordance = 0.74 and 0.63, respectively). The LenStar systematically underestimated ocular dimensions when compared to A-scan ultrasound (mean magnitude of difference = 0.11-0.57 mm). This difference could be minimized using linear calibration functions to equate LenStar data with ultrasound data. When this method was applied, the values between instruments were in excellent absolute agreement (mean magnitude of difference = 0.004-0.01 mm). In conclusion, the LenStar reliably measured ocular dimensions in young monkeys. When an appropriate calibration function is applied, the LenStar can be used as a substitute for A-scan ultrasonography., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Metrics derived from the human eye are increasingly used as biomarkers and endpoints in studies of cardiovascular, cerebrovascular and neurological disease. In this context, it is important to account for potential confounding that can arise from differences in ocular dimensions between individuals, for example, differences in globe size., Methods: We measured axial length, a geometric parameter describing eye size from T 2 -weighted brain MRI scans using three different image analysis software packages (Mango, ITK and Carestream) and compared results to biometry measurements from a specialized ophthalmic instrument (IOLMaster 500) as the reference standard., Results: Ninety-three healthy research participants of mean age 51.0 ± SD 5.4 years were analyzed. The level of agreement between the MRI-derived measurements and the reference standard was described by mean differences as follows, Mango - 0.8 mm; ITK - 0.5 mm; and Carestream - 0.1 mm (upper/lower 95% limits of agreement across the three tools ranged from 0.9 mm to - 2.6 mm). Inter-rater reproducibility was between - 0.03 mm and 0.45 mm (ICC 0.65 to 0.93). Intra-rater repeatability was between 0.0 mm and - 0.2 mm (ICC 0.90 to 0.95)., Conclusions: We demonstrate that axial measurements of the eye derived from brain MRI are within 3.5% of the reference standard globe length of 24.1 mm. However, the limits of agreement could be considered clinically significant. Axial length of the eye obtained from MRI is not a replacement for the precision of biometry, but in the absence of biometry it could provide sufficient accuracy to act as a proxy. We recommend measuring eye axial length from MRI in studies that do not have biometry but use retinal imaging to study neurodegenerative changes so as to control for differing eye size across individuals., (© 2022. The Author(s).)

Background: The purpose of this study is to compare the biometric parameters and intraocular lens (IOL) power calculation by a new swept-source optical coherence tomography (SS-OCT) biometer with those by a partial coherence interferometry (PCI) biometer., Methods: Medical records of 175 eyes from 175 patients were retrospectively reviewed. One of two monofocal IOLs (Tecnis ZCB00 or Acrysof SA60AT) were implanted in the eyes. Axial length (AL), mean keratometry (Km), J0, J45 and anterior chamber depth (ACD) were compared between PCI and SS-OCT biometers. The refractive mean error (ME) and refractive mean absolute error (MAE) were also compared. Examination failure rates were calculated in each device., Results: Out of 175 eyes, 150 eyes were successfully examined by both devices. AL was measured slightly shorter when using SS-OCT than PCI biometer, while Km was measured higher (P < .0001, P = .03, respectively, paired t-test). J0, J45 and ACD were not significantly different between two devices. ME and MAE calculated using SRK-T, Hoffer Q, and Haigis formula were not significantly different except MAE calculated with Haigis formula for Tecnis ZCB00 IOLs (P = .03, paired t-test). The examination failure rates were 14.29 and 1.14% when using the PCI and SS-OCT biometers, respectively., Conclusions: AL and Km don't seem to be comparable between two devices, while J0, J45 , and ACD do. IOL power calculation using SRK-T and Hoffer Q was correlated between the devices. The penetration ability of a SS-OCT biometer is superior.

Purpose: To compare and evaluate the agreement between the measurements obtained with a swept-source optical coherence tomography (OCT)-based biometer, the IOLMaster® 700 (IOLM), and those obtained by an optical biometer based on optical low-coherence interferometry (OLCI), the Aladdin (ALD); To evaluate the ability to perform biometric measurements in those eyes with transparency alterations., Methods: Fifty-five eyes of 55 subjects were included in this study. Axial length (AL), corneal power (K, in diopters) and its astigmatism, anterior chamber depth (ACD), central corneal thickness (CCT), and lens thickness (LT) measures were obtained within both biometers, Zeiss IOLMaster 700 and Topcon Aladdin. Results were analyzed and compared using the Student's paired samples t-test, Bland-Altman analysis and intraclass correlation coefficient (ICC)., Results: Mean age was 73.12 ± 2.63 (62-89 years). The IOLM mean AL, K, and LT values did not show a statistically significant difference from ALD values and showed excellent agreement and correlation (ICC = 1.000, 0.970, 0.952). IOLM measured a lower mean ACD (-0.036 mm) and higher CCT measurements (9.296 μm). Those results were statistically different (p < 0.001 in both cases) but showed an excellent correlation coefficients (ICC = 0.994, 0.938). IOLM was able to obtain measures from all the eyes examined, while ALD did not measure in two cases with dense nuclear cataract. ALD showed spherical K measures in 7.27% of cases., Conclusion: Overall a quite good agreement between IOLM and ALD was found. ALD showed spherical keratometry measures in 7.27% of cases. IOLMaster 700 was more effective in obtaining AL measurements in eyes with dense cataracts.

Purpose: To evaluate the repeatability of a new biometer using Scheimpflug technology combined with partial coherence interferometry (PCI) (Pentacam AXL) and its agreement with a device based on optical low-coherence reflectometry (OLCR), the Allegro Biograph., Setting: Oftalvist Centro Integral Ocular Jerez, Jerez de la Frontera, Spain., Design: Evaluation of a diagnostic test., Methods: The mean keratometry (K), central corneal thickness (CCT), anterior chamber depth (ACD), and axial length (AL) were measured with the 2 devices 3 times by the same examiner in 2 groups (patients with cataract and patients without cataract). The repeatability was determined using the within-subject standard deviation, test-retest repeatability, coefficient of variation, and intraclass correlation coefficient. The correlation was evaluated with the Pearson coefficient and interchangeability with the Bland-Altman plot., Results: Eighty eyes (40 eyes in each group) of 80 patients were analyzed. Significant differences were found between the Scheimpflug-PCI device and the OLCR device for mean K in the normal group (P < .001) and for CCT in the normal group (P < .05) and the cataract group (P < .001). There were no differences between devices in ACD and AL in either group. The repeatability between devices was similar. Although a significant correlation between devices was found for all measurements (all P < .001), wide limits of agreement were found in both groups for all biometric parameters., Conclusions: The Scheimpflug-PCI and OLCR devices showed excellent intravisit repeatability and high correlation for mean K, CCT, ACD, and AL in healthy and cataractous eyes. No differences were found in AL; however, the 2 devices might not be interchangeable., (Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Background: This study aimed to evaluate the prediction accuracy of postoperative refractions using partial coherence interferometry (IOL-Master) and applanation ultrasound (AL-3000) assisted with corneal topography (TMS-4) in eyes that had undergone myopic laser-assisted in situ keratomileusis (LASIK)., Methods: Haigis-L formula, Koch-Maloney method using Haigis formula, Shammas clinically derived K-value (simulated keratometric value) correction (Shammas c.d.) using Haigis formula, and Shammas post-LASIK (Shammas-PL) formula were used in eyes with myopic LASIK. Constants were derived from the optimized constants in 133 virgin eyes. Refractive outcomes were determined by streak retinoscopy and subjective manifest refraction. Methods and formulas were evaluated by mean error (ME), standard deviation (SD), range of error, mean absolute error (MAE), median absolute error, 95% confidence interval of MAE, and percentage of eyes within ±0.5 diopter (D), ±1.0 D, and ±1.5 D of prediction., Results: SDs of the Haigis-L, Koch-Maloney method using the Haigis formula, Shammas c.d. using the Haigis formula, and the Shammas-PL formula using IOL-Master were 0.721, 0.695, 0.695, and 0.698; and those using AL-3000 assisted with TMS-4 were 0.782, 0.741, 0.743, and 0.778, respectively., Conclusions: No-history methods that corrected corneal power with measurements using IOL-Master were promising in myopic post-LASIK eyes, but still a gap in prediction accuracy exists between virgin eyes and post-LASIK eyes.

Purpose: To compare axial length (AL) measurements between a swept-source optical coherence tomography (SS-OCT) biometer (IOLMaster 700) and a partial coherence interferometry (PCI) biometer (IOLMaster, version 5.4) in myopic eyes., Setting: Severance Hospital, Yonsei University, Seoul, South Korea., Design: Prospective evaluation of a diagnostic test., Methods: This study enrolled patients with a diagnosis of myopia in their medical records. Two consecutive AL measurements were performed in each eye in random order using the 2 biometers. Subanalysis was performed according to lens status, fixation status, degree of myopia, and the presence of posterior staphyloma. The interdevice agreement was evaluated with Bland-Altman analyses and paired t tests., Results: This study comprised 219 eyes of 117 patients. During a fixation check using SS-OCT, 19.6% of eyes showed fixation loss. Overall, the SS-OCT biometer showed a longer AL than the PCI biometer. (P < .001) In a subanalysis that categorized eyes according to lens status, fixation status, degree of myopia, and the presence of posterior staphyloma, the SS-OCT biometer also showed longer ALs than the PCI biometer. Of eyes with good fixation, significant differences in AL measurements between devices were detected for those with posterior staphyloma (P < .001) but not for those without posterior staphyloma (P = .104)., Conclusions: The 2 devices showed differences in AL measurements in myopic eyes. Fixation status and the presence of posterior staphyloma were important factors in these differences. For myopic eyes with posterior staphyloma, the SS-OCT biometer is expected to produce more precise AL measurements because it allows evaluation of the fixation status., (Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To analyze the influence on intraocular lens (IOL) power calculation of corneal radii measured by the Verion Image-Guided System in comparison with those measured by partial coherence interferometry (PCI) (IOLMaster) and optical low-coherence reflectometry (OLCR) (Lenstar) systems., Setting: International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany., Design: Prospective case series., Methods: One eye of ophthalmologically healthy volunteers was examined with the image-guided, PCI, and OLCR systems. Corneal radii could be measured with all 3 devices; axial length (AL) and anterior chamber depth (ACD) could be measured with PCI and OLCR only. The IOL power calculations for the Acrysof SN60WF IOL using 4 formulas were compared between the image-guided system and both the PCI device and OLCR device. For IOL calculation with the image-guided system, the AL and ACD of the device used for comparison were applied., Results: Of the 150 volunteers, 136 (mean age 39.60 years ± 17.31 [SD]) had valid measurements with all 3 devices and were included in the analysis. Compared with PCI, the image-guided system measured statistically significant larger values for corneal radii and IOL power calculations for all 4 formulas. There were no statistically significant differences between the image-guided system and the OLCR device. In both groups, the surgeon would have chosen the same IOL power in approximately 60% to 65% of cases and a ±0.5 diopter different IOL power in approximately 30% to 35% of cases when using the image-guided system., Conclusions: The IOL power calculation using the image-guided system showed statistically significant differences compared with the PCI device but not when compared with the OLCR device. The clinical relevance of this theoretical approach remains to be evaluated., Financial Disclosure: Drs. Auffarth and Holzer received travel grants and lecture fees from Alcon Pharma GmbH and Carl Zeiss Meditec AG., (Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the level of agreement, repeatability, and correlation of 2 optical biometers, the IOLMaster (based on partial coherence interferometry [PCI]) and Aladdin (based on optical low-coherence interferometry [OLCI]) in terms of axial length (AL), mean keratometry (K), anterior chamber depth (ACD), and corneal diameter., Setting: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom., Design: Prospective comparative case series., Methods: Each participant had biometry with both biometers. The level of agreement between the biometers was calculated using the Bland-Altman method. Double-angle polar plots were used to display the astigmatism vectors. Internal consistency was computed with the Cronbach α coefficient of reliability, whereas the dispersion of probability distribution was assessed with the coefficient of variation (CoV). The intraoperator repeatability was analyzed using the intraclass correlation coefficient (ICC); the AL was evaluated in all eyes and the mean K and the ACD in a subset of eyes., Results: The study comprised 215 eyes; the ICC for the mean K and ACD was calculated in a subset of 54 eyes. There was a statistically significant difference between the 2 biometers in all measurements (P < .05). The level of agreement was high with both methods. The ICC and internal consistency were excellent with both biometers; the CoVs were low., Conclusions: The OLCI biometer provided good agreement and repeatability compared with the PCI biometer, the current gold standard in ocular biometry. Further comparative studies are necessary to clearly define the role of the OLCI biometer in predicting postoperative refractive outcomes., Financial Disclosures: Dr. Findl is a scientific advisor to Carl Zeiss Meditec AG. None of the other authors has a financial or proprietary interest in any material or method mentioned., (Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the repeatability of keratometry of the Verion image-guided system and to compare the keratometry (K) values with those of established biometric devices., Setting: International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany., Design: Prospective case series., Methods: One randomly chosen eye of volunteers was examined with partial coherence interferometry (PCI) (IOLMaster 500), optical low-coherence reflectometry (OLCR) (Lenstar LS 900), a Scheimpflug device (Pentacam HR), and the new image-guided system by the same examiner. None of the eyes had ocular pathology. Three consecutive measurements were performed with the image-guided system and 1 with the other devices. The flat, steep, and average corneal radii; steep axis; and white-to-white (WTW) distance were analyzed and compared., Results: One hundred twenty-three eyes of 123 volunteers (mean age 37.9 years ± 16.2 [SD]) had valid measurements for all examinations and were available for analysis. The image-guided system measured statistically significant smaller flat, steep, and average corneal radii than the Scheimpflug device, statistically significant larger flat and average corneal radii than the PCI device, and no statistically significant different values than the OLCR device. The measured steep axis did not differ significantly in any comparison. The WTW measurements were significantly higher than those of all other devices. The analysis of repeatability of the image-guided system showed high intraclass correlation coefficients (range 0.919 to 0.997)., Conclusions: The new image-guided system had high repeatability for K, steep axis, and WTW measurements. The WTW measurements with the image-guided system were significantly higher than those using the other devices., Financial Disclosure: None of the authors has a financial or proprietary interest in any material or method mentioned., (Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the repeatability and agreement of the anterior segment measurements obtained using the Galilei dual Scheimpflug analyzer (Galilei DSA; Ziemer) and Nidek AL Scan (Nidek CO, Aichi, Japan) biometry in keratoconic and normal eyes., Methods: Three consecutive measurements were performed by the same examiner using both devices in 62 healthy and 88 keratoconic eyes. Central corneal thickness (CCT), anterior chamber depth, keratometry readings (K) [in flattest meridian (Kf), in steepest meridian (Ks), and mean (Km)], and white-to-white distance were evaluated. Repeatability was assessed by calculating the within-subject SD and coefficient of variation. The agreement between both devices was assessed using the Bland-Altman method., Results: Both devices achieved excellent repeatability for all parameters in each group. The 95% limits of agreement (LoA) between both devices were also very narrow and acceptable for all parameters in normal corneas. However, the 95% LoA for agreement was large for CCT and measurements related to K (Kf, Ks, and Km) using both 2.4 and 3.3 mm in keratoconic eyes. In addition, compared with the Galilei DSA, K values of the Nidek AL Scan using a diameter of 3.3 mm showed slightly closer 95% LoA than those obtained using a diameter of 2.4 mm., Conclusions: In normal eyes, the Galilei DSA and Nidek AL Scan can be used interchangeably for anterior segment measurements. In keratoconic eyes, both devices yielded interchangeable anterior chamber depth and white-to-white distance measurements, whereas CCT and keratometry measurements showed clinically significant differences.

Purpose: To compare the refractive results of cataract surgery measured by applanation ultrasound and the new partial coherence interferometer, AL-scan., Methods: Medical records of 76 patients and 104 eyes who underwent cataract surgery from January 2013 to June 2013 were retrospectively reviewed. Biometries were measured using ultrasound and AL-scan and intraocular lens power was calculated using the SRK-T formula. Automatic refraction examination was done 1 month after the operation, and differences between the ultrasound group and AL-scan group were compared and analyzed by mean absolute error., Results: Mean axial length measured preoperatively by the ultrasound method was 23.53 ± 1.17 mm while the lengths measured using the AL-scan were 0.03 mm longer than that of the ultrasound group (23.56 ± 1.15 mm). However, there was not a significant difference in this finding (p = 0.638). Mean absolute error was 0.34 ± 0.27 diopters in the ultrasound group and 0.36 ± 0.31 diopters in AL-scan group, which showed no significant difference (p = 0.946) in precision of predicting postoperative refraction., Conclusions: Although the difference was not statistically significant, intraocular lens calculations done by the AL-scan were nearly similar in predicting postoperative refraction compared to those of applanation ultrasound, however more precise measurements may be obtained if the axial length is longer than 24.4 mm. Except in the case of opacity in the media, which makes obtaining measurements with the AL-scan difficult, AL-scan could be a useful biometry in cataract surgery.

Purpose: To establish repeatability and validity of a partial coherence interferometry (PCI) device in patients with astigmatism., Setting: Industry and university., Design: Observational studies., Methods: A prospective study determined the agreement between the IOLMaster 500 PCI device and the Marco 1-position manual keratometer for measurement of mean corneal power, astigmatic power, and axis. Interinstrument and interoperator reproducibility was also assessed. A retrospective study determined the agreement between the PCI device and the Javal 2-position manual keratometer. Repeatability was also assessed. The 95% limits of agreement (LoA) were determined for all comparisons., Results: Comparing the PCI device and the 1-position manual keratometer, the axis was within 5 degrees in 72.1% of eyes; the cylinder power differed by 0.18 diopter (D) (95% LoA, ±0.45 D) and the mean power by 0.33 D (95% LoA, ±0.25 D). Comparing the PCI device and the 2-position manual keratometer, the axis was within 5 degrees in 77.1% of eyes. The mean difference in cylinder power between the 2 instruments was close to zero (95% LoA, ±0.37 D); however, the mean power differed by 0.34 D (95% LoA, ±0.25 D). The repeatability of the PCI device was better than that of both manual keratometers., Conclusions: Agreement between the PCI device and the 2-position manual keratometer for measures of corneal astigmatism and axis was excellent. The 1-position manual keratometer gave slightly lower estimates of corneal astigmatism, although the agreement for axis was excellent. Thus, the PCI device is an appropriate choice for the calculation of toric intraocular lenses., Financial Disclosure: Dr. Bullimore is a consultant to Carl Zeiss Meditec AG and Alcon Surgical, Inc. Drs. Buehren and Bissmann are employees of Carl Zeiss Meditec AG., (Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Background: To establish whether simulated keratometry values obtained by corneal mapping (videokeratography) would provide a superior refractive outcome to those obtained by Zeiss IOLMaster (partial coherence interferometry) in routine cataract surgery., Design: Prospective, non-randomized, single-surgeon study set at the The Royal United Hospital, Bath, UK, District General Hospital., Participants: Thirty-three patients undergoing routine cataract surgery in the absence of significant ocular comorbidity., Methods: Conventional biometry was recorded using the Zeiss IOLMaster. Postoperative refraction was calculated using the SRK/T formula and the most appropriate power of lens implanted. Preoperative keratometry values were also obtained using Humphrey Instruments Atlas Version A6 corneal mapping., Main Outcome Measures: Achieved refraction was compared with predicted refraction for the two methods of keratometry after the A-constants were optimized to obtain a mean arithmetic error of zero dioptres for each device., Results: The mean absolute prediction error was 0.39 dioptres (standard deviation 0.29) for IOLMaster and 0.48 dioptres (standard deviation 0.31) for corneal mapping (P = 0.0015). Keratometry readings between the devices were highly correlated by Spearman correlation (0.97). The Bland-Altman plot demonstrated close agreement between keratometers, with a bias of 0.0079 dioptres and 95% limits of agreement of -0.48-0.49 dioptres., Conclusions: The IOLMaster was superior to Humphrey Atlas A6 corneal mapping in the prediction of postoperative refraction. This difference could not have been predicted from the keratometry readings alone. When comparing biometry devices, close agreement between readings should not be considered a substitute for actual postoperative refraction data., (© 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.)

Purpose: We aimed to describe norms for the distribution of axial length (AL) and other ocular biometric parameters in an older Caucasian population, measured using partial coherence laser interferometry (Zeiss IOL Master; Carl Zeiss AG, Oberkochen, Germany), a technique now routinely used in measuring AL before cataract surgery. We also aimed to assess age and gender relationships with these parameters and their correlations with spherical equivalent refraction (SER)., Design: Cross-sectional analysis of the Blue Mountains Eye Study (BMES) cohort at the examinations (10-year follow-up examination)., Participants: From 2002 to 2004, 1952 persons (76% of surviving baseline BMES participants) aged 59 years or older had ocular biometry measured at the 10-year examinations., Methods: Spherical equivalent refraction was calculated as the sum of sphere +0.5 cylinder power, after protocol refraction. Measurements of AL, corneal curvature (K1), anterior chamber depth (ACD), and corneal diameter (WTW) were performed using the IOL Master. Only right phakic eyes (n = 1335) with biometry data were included., Main Outcome Measures: Axial length distribution., Results: Mean AL was 23.44 mm (95% confidence interval [CI], 23.38-23.50) and was greater in men, 23.76 mm (CI, 23.68-23.84), than in women, 23.19 mm (CI, 23.11-23.27). The mean K1, ACD, and WTW were 43.42 diopters (D), 3.10 mm, and 12.06 mm, respectively. The AL and ACD distributions were both positively skewed and peaked, whereas the WTW and K1 distributions were near normal. From age 59 years or older, a mean reduction in AL with age was observed (P for trend = 0.005), 0.12 mm per decade (P = 0.0176) in women but only 0.02 mm per decade (P = 0.6319) in men. Mean SER was 0.58 D, and the distribution was peaked with a negative skew. The SER was negatively correlated with both AL (beta coefficient -0.688) and ACD (beta coefficient -0.222), but not with K1 or WTW., Conclusions: These data provide normative values in the older general population for AL measured using the IOL Master. Axial length distribution was peaked and skewed, suggesting an active modulation process., (Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the agreement among three different optical methods in measuring anterior chamber depth (ACD), central corneal thickness (CCT), and pupil diameter., Methods: One hundred eyes of 50 healthy patients (25 men, 25 women) were enrolled in the study. Mean patient age was 25 years (range: 21 to 32 years). Exclusion criteria were history of any intraocular or corneal surgery, contact lens wear, corneal anomalies, and spherical refraction >5.00 diopters (D) or cylindrical refraction >2.00 D. All measurements were done by the same operator under mesopic light conditions and repeated using three different optical methods: Visante optical coherence tomography (OCT) (Carl Zeiss Meditec), Orbscan (Bausch & Lomb), and Pentacam (Oculus Optikgeräte GmbH)., Results: Mean CCT as measured by Visante OCT, Orbscan, and Pentacam was 529+/-30.5 microm, 554+/-32.7 microm, and 552+/-29.3 microm, respectively. Mean ACD values were 2.94+/-0.34 mm, 2.84+/-0.33 mm, and 2.98+/-0.33 mm, respectively. Mean pupil diameter measurements were 4.87+/-1.09 mm, 4.0+/-0.67 mm, and 3.05+/-0.59 mm, respectively. The Visante OCT measured CCT thinner and Orbscan measured ACD shallower than the other two methods. All three methods measured pupil diameters significantly different., Conclusions: This study found some statistically significant but clinically insignificant differences among the optical methods assessed. The differences are small and do not influence decisions for refractive surgery in clinical practice.

Purpose: To determine whether intraocular lens (IOL) power calculations for cataract surgery as measured by postoperative refractive error using partial coherence interferometry (PCI) are more accurate in improving postoperative outcomes than applanation ultrasound biometry (AUS)., Methods: A double-blind randomized controlled trial consisting of 205 patients was undertaken by the Southern Health Ophthalmology Unit, Victoria, Australia. Mean absolute postoperative refractive error (MAE) represented the dependent variable; the biometric technique (PCI; AUS) used to determine the IOL power to be implanted in the surgical eye represented the independent variable. An intention-to-treat analysis was used to prevent loss of randomization caused by the effects of crossover and drop-out., Results: The MAE in patients with implanted PCI-calculated IOLs was 0.40 +/- 0.37 D (SD; 95% confidence interval [CI], 0.32-0.48 D) compared with 0.45 +/- 0.41 D (SD; 95% CI, 0.36-0.54 D) for patients with implanted AUS-calculated IOLs. There was no statistically significant difference between MAE in patients with implanted PCI-calculated IOLs and that in patients with AUS-calculated IOLs in analysis of best possible outcomes (t(167) = 1.0, P = 0.315)., Conclusions: The results of this trial demonstrated that the calculation of IOL power based on ocular axial length measurement with PCI technology provided no clinical advantage over conventional applanation ultrasound, as measured by postoperative refractive outcome (anzctr.org.au number, ACTRN12608000077369).

Purpose: To evaluate the test-retest repeatability of axial length (AL) measurements made with the IOLMaster in children with a wide range of myopic refractive errors, and to clarify the relationship between the AL and other refractive components., Methods: The subjects were 95 children (mean age +/- SD, 10.8 +/- 1.3 years; range, 7-13 years; mean refractive error; -4.37 +/- 1.43 D; range, -1.50 to -8.19 D) who participated in a myopia-control trial. The AL of the right eye was measured three times using an IOLMaster, and the mean value was regarded as the representative measurement. After 5 min, the measurement was performed again, and the repeatability was evaluated by analyzing the distribution of differences between the two measurements. The relationships between the AL and age, cycloplegic autorefraction (RE), and corneal radius of curvature (CR) were also examined., Results: The repeatability of the IOLMaster measurements was +/-0.05 mm (corresponding to a refractive error of +/-0.12 D) and was not affected by age or RE. AL was negatively correlated with RE (RE = -0.68 x AL + 12.74, r = -0.37) and positively correlated with CR (CR = 0.21 x AL + 2.53, r = 0.69). The highest correlation was found between the ratio of AL to CR and RE (AL/CR = -0.04 x RE + 3.08, r = -0.76). No association was observed between age and AL, nor between CR and RE., Conclusions: The IOLMaster provides high repeatability in AL measurement in myopic children. The associations between AL and each refractive component found in this study were consistent with those in previous studies that used the ultrasound A-mode method, except for slightly higher AL/CR ratios in our study.

A new technique has been developed to determine the axial length of the human eye in vivo. Based on laser interferometry in conjunction with the Doppler technique, it uses partially coherent light. This new technique complies with laser safety regulations. High accuracy is achieved, the optical length (OL) can be determined within +/- 30 microns, and the reproducibility of the geometric eye length is greater than +/- 25 microns. Possible errors are discussed. First comparisons with the ultrasound technique yield good agreement for emmetropic subjects and for subjects with a myopia of up to 10 diopters. The advantages of the laser doppler interferometry (LDI) technique are high accuracy, high transversal resolution, and more comfort for the patient (it is a noncontact method; no anesthesia is needed). Possible future applications of LDI, like measurements of fundus profiles and of retinal thickness, are mentioned.

Biometric measurements in the context of myopia are fundamental to detect eyes at risk of developing myopia and during the follow-up of patients with myopia control treatment. Thus, the accuracy of biometers has high clinical relevance. The Myopia Master is a new biometer based on partial coherence interferometry especially dedicated to the follow-up of myopic patients. This study aims to assess the repeatability of the Myopia Master and evaluate its agreement with a swept-source optical coherence interferometry biometer (IOL Master 700). This cross-sectional prospective study assessed the biometric parameters of two groups of myopes (age range: 8–16 years old), spectacle corrected (n = 60) and orthokeratology contact lens wearers (n = 60). One senior optometrist performed two consecutive measurements per instrument, which included axial length, mean keratometry and horizontal visible iris diameter (HVID). The repeatability of each device and the agreement between devices were assessed by the dispersion of the measurement differences, for AL, mean keratometry, corneal astigmatism and HVID. The two biometers measured approximately the same value in both measurements. Test–retest repeatability tended to be lower than clinical significant thresholds, in particular, for AL and mean keratometry. Corneal-related parameters tended to have lower repeatability in the orthokeratology group, especially mean keratometry. The agreement between instruments revealed statistically significant differences between devices with the SS-OCT measuring longer eyes, steeper corneas and larger HVID. In a paediatric population, the Myopia Master showed clinically acceptable repeatability levels, but the IOL Master 700 demonstrated superior repeatability. Eyes treated with orthokeratology may compromise the repeatability of the corneal-related parameters. The Myopia Master and the IOL Master 700 are repeatable devices appropriate for monitoring myopia progression, but the differences observed do not allow their use interchangeably. [ABSTRACT FROM AUTHOR]

Purpose: : To assess the repeatability of ocular measurements, particularly astigmatism, taken using the latest version of an swept-source optical coherence tomography (SS-OCT) device, IOLMaster 700.Methods: This prospective observational study done in a private eye care centre. Study included 213 eyes of 152 patients diagnosed with cataract. Axial length (AL), Anterior corneal astigmatism (ΔK), Total corneal astigmatism (ΔTK), Aqueous depth (AD), Lens thickness (LT), Iris barycentre distance (IBD) and White to white distance (WTW) were analysed; three measurements were taken for each patient in the same sitting by the same examiner in an undilated state using the SS-OCT device. Repeatability was analysed using intraclass coefficient (ICC) and coefficient of variation (CV) measures, and astigmatism values were transformed into vector components (J0/J45) and categorised based on magnitude.Results: Astigmatism vector components (J0/J45) showed poor repeatability (ICC < 0.5 and CV > 0), while iris coordinates (IBD) and astigmatism magnitude had good correlation (ICC > 0.9) but more variations between the readings which was least for magnitude ≥ 1.5D; however, rest of the parameters demonstrated excellent repeatability (ICC > 0.9 with P value < 0.05).Conclusion: IOLMaster 700 demonstrated good reliability for the parameters measured, although, for astigmatism and iris barycentre distance, more number of readings and cross reference with other devices may be required to get clinically accurate results. [ABSTRACT FROM AUTHOR]

Copyright of Türkiye Klinikleri Journal of Ophthalmology is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims: To determine the reliability of transpalpebral ultrasound in B-mode (B-TUS) with a high-resolution linear probe (18 MHz) in estimating both the ocular anterior chamber depth (ACD) and axial length (AL), as well as its agreement with the IOL Master 500 optical biometer.Material and Methods: Cross-sectional study on 82 eyes of 41 volunteers with no history of eye disease. ACD and AL were determined using B-TUS and the IOL Master 500. The agreement between the two tech-niques and the variability of B-TUS (inter- and intra-observer) were analyzed with the Bland-Altman method. To this end, the mean difference between measures±1.96 SD was calculated to determine the limits of agreement (LoA).Results: The mean difference±1.96SD between B-TUS and the IOL Master 500 was -0.41±0.25mm for ACD (p<0.001) and -0.48±0.45 mm for AL (p<0.001). The maximum variability for B-TUS (average±1.96SD) was 0.00±0.35 mm at the inter-observer level for AL, and 0.00±0.18mm at the intra-observer level for AL.Conclusion: The determination of ACD and AL by B-TUS has a good re-liability and variability, in line with other sonographic techniques. However, it systematically provides smaller measurements than those obtained with the IOL Master 500, similar to the conventional ultrasound techniques. B-TUS could be useful in the assessment and follow-up of a wide range of ophthalmic diseases, in which a high accuracy in ACD and AL is not determinant. [ABSTRACT FROM AUTHOR]

Purpose. To compare ocular biometric parameters between urban and rural cataract patients in Shanghai, China. Methods. A study of ocular biometry records from urban and rural hospitals was performed for cataract patients at least 50 years of age. The ocular biometrical parameters, which were measured with partial coherence laser interferometry (IOL Master, Zeiss), were axial length (AL), anterior chamber depth (ACD), radius of corneal curvature (K, including steep/flat/average K), astigmatism, and axis. Only the right eye record of each patient was analysed. Results. Ocular biometric data included 2839 urban patients (73.15 ± 9.54 years) and 2646 rural patients (73.64 ± 7.32 years). Mean AL, ACD, and K were 24.35 ± 2.34 mm, 3.14 ± 0.58 mm, and 44.38 ± 1.52 D, respectively, in urban patients and 23.58 ± 1.70 mm, 3.08 ± 0.57 mm, and 44.53 ± 1.50 D, respectively, in rural patients. The urban subjects had significantly longer axial lengths (in both univariate and multivariate linear regression analyses) and deeper ACDs (in univariate analysis) than rural subjects p < 0.01 . There was no significant difference in steep K, flat K, and average K between the two groups. With-the-rule (WTR) corneal astigmatism was found in 1787 eyes (32.58%), against-the-rule (ATR) corneal astigmatism was found in 2727 eyes (49.72%), and oblique corneal astigmatism was found in 971 eyes (17.70%). Conclusions. We report biometry and astigmatism data in a large cohort of urban and rural adult subjects for the first time. In our study, a short AL, shallow ACD, and axis turned in an ATR direction had higher prevalence rates in the rural subjects. This profile of ocular biometric data and corneal astigmatism will be helpful in planning for intraocular lens (IOL) power calculations and astigmatism correction in subjects in different locations. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To compare biometry measurements obtained by a partial interferometer biometer (IOLMaster 500) to the new Scheimpflug tomography with an integrated axial length biometer module (Pentacam AXL). Patients and Methods: Cataract patients who underwent biometric measurements with the IOL Master 500 and the Pentacam AXL from July to November 2017 were enrolled in this study. Comparisons were performed for axial length (AL), keratometry (K), and anterior chamber depth (ACD). The Pearson correlation coefficient and the 95% limits of agreement (LoA) were calculated. Paired Student's t-tests and Bland-Altman plots were used to assess the differences between devices. Results: One hundred and sixty-six eyes of 92 patients were analyzed. There were no statistically significant differences in AL (p=0.558) or flat K (p=0.196) values between the IOL Master 500 and Pentacam AXL measurements. Statistically significant differences were found between the two devices with respect to steep K, ACD, and mean K measurements (p< 0.001). Conclusion: Both devices provided similar measurements of AL and flat K, though there were statistically significant differences in ACD, steep K, and mean K measurements. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate whether different anterior chamber depth (ACD) affects the predictive accuracy of intraocular lens formulas in eyes with axial length (AL) less than 22 mm. Methods: Eighty-five eyes of 85 patients with AL less than 22 mm were included in this retrospective study, which were divided into three groups: Group 1, ACD less than 2.4 mm; Group 2, ACD between 2.4 and 2.9 mm; and Group 3, ACD greater than 2.9 mm. Optical biometry with partial coherence interferometry was performed in all cases. The median absolute error (MedAE) was compared by Friedman's test, using the optimized lens constant, among seven formulas (Barrett Universal II, Haigis, Hill-RBF, Hoffer Q, Holladay 1, Holladay 2, and SRK/T) in each group. Results: Friedman's test showed no significant difference in MedAE among all formulas in Groups 1 and 3. However, as the Haigis formula had the highest MedAE and lowest percentage of eyes within ±0.25 Diopter, it is least preferred in Group 1. On the contrary, in Group 3 it fared the best, having the least MedAE and highest percentage of eyes within ±0.25 Diopter. In Group 2, Friedman's test gave significant difference, and post-hoc analysis showed statistical superiority of Haigis over the Holladay 1 (p=0.02), Holladay 2 (p=0.01), Hill-RBF (p=0.04), and SRK/T (p=0.02) formulas. However, there was no statistical difference between the Barrett Universal II, Haigis, and Hoffer Q formulas. Conclusion: Considering the ACD in eyes with AL less than 22 mm, Haigis is the preferred formula while SRK/T proved to be the worst formula in Groups 2 and 3. [ABSTRACT FROM AUTHOR]

Background: To evaluate the accuracy of biometric measurements by a swept-source optical coherence tomography (SS-OCT) based biometry for intraocular lens (IOL) power calculation.Methods: This retrospective observational study enrolled 431 patients undergoing cataract surgery. The charts were reviewed to investigate the failure rate of axial length (AL) measurement of the SS-OCT biometer, partial coherence interferometry (PCI), and A-scan ultrasonography (US) according to cataract type and severity. AL and keratometry in 164 eyes with the same IOL inserted were measured using the SS-OCT biometer, PCI, and A-scan US. The SRK/T formula was used to calculate IOL power. The mean absolute error (MAE) and percentage of eyes with a prediction error (PE) of ±0.50 D were compared.Results: The AL measurement failure rate was 0.00% for A-scan US, 2.32% for the SS-OCT biometer, and 15.31% for PCI. The number of eyes measured using three devices (SS-OCT biometer, PCI, and A-scan US) was 128 (Group A) and the number of eyes measured using two devices (SS-OCT biometer and A-scan US) was 36 (Group B). The score of posterior subcapsular opacity was significantly different between two groups (p < .001). The SS-OCT biometer and PCI showed significantly lower MAE compared to A-scan US in Group A (p = 0.027). Using SS-OCT biometer, MAE showed no significant difference between Group A (0.36 ± 0.27) and Group B (0.36 ± 0.31) (p = 0.785). Whereas, MAE of A-scan US was significantly higher than Group A (0.47 ± 0.39) in Group B (0.64 ± 0.36) (p = 0.023).Conclusions: Using biometry with advanced OCT is useful in clinical practice as it is more effective in obtaining biometric measurements in the eyes with PSC and provides accurate measurements for IOL power calculation regardless of cataract type and severity.Trial Registration: Retrospectively registered. Registration number: KC16RISI1020 . Registered 03 January 2018. [ABSTRACT FROM AUTHOR]

Purpose To analyze the precision of 6 intraocular lens (IOL) power calculation formulas in predicting refractive outcome in eyes with an axial length (AL) less than 22.0 mm. Setting Department of Ophthalmology, All India Institute of Medical Sciences, Raipur, India. Design Retrospective observational study. Methods Patients with an AL less than 22.0 mm were included in the study. If both eyes were eligible, a randomly selected eye was chosen. Optical biometry with partial coherence interferometry (PCI) was performed in all cases. Six formulas were analyzed: Barrett Universal II, Haigis, Hoffer Q, Holladay 2, RBF Method and SRK/T. The mean numerical error was defined as the difference between the actual postoperative spherical equivalent (SE) at the 1-month follow-up and the predicted postoperative SE. The median absolute error was calculated and compared between all 6 formulas after the zeroing of the mean numerical error by adjusting the lens constant individually for each formula. Results The study comprised 50 eyes of 50 patients. The Friedman test was applied to compare the median absolute error between the 6 formulas after the zeroing of the mean numerical error. Post hoc analysis and Bonferroni correction for multiple comparisons showed no significant statistical difference between them. Conclusion The Barrett Universal II, Haigis, Hoffer Q, Holladay 2, RBF method and SRK/T formulas were equally accurate in predicting the IOL power in eyes shorter than 22.0 mm. [ABSTRACT FROM AUTHOR]

Purpose: To compare and evaluate the agreement between the measurements obtained with a swept-source optical coherence tomography (OCT)-based biometer, the IOLMaster® 700 (IOLM), and those obtained by an optical biometer based on optical low-coherence interferometry (OLCI), the Aladdin (ALD); To evaluate the ability to perform biometric measurements in those eyes with transparency alterations.Methods: Fifty-five eyes of 55 subjects were included in this study. Axial length (AL), corneal power (K, in diopters) and its astigmatism, anterior chamber depth (ACD), central corneal thickness (CCT), and lens thickness (LT) measures were obtained within both biometers, Zeiss IOLMaster 700 and Topcon Aladdin. Results were analyzed and compared using the Student’s paired samples t-test, Bland–Altman analysis and intraclass correlation coefficient (ICC).Results: Mean age was 73.12 ± 2.63 (62–89 years). The IOLM mean AL, K, and LT values did not show a statistically significant difference from ALD values and showed excellent agreement and correlation (ICC = 1.000, 0.970, 0.952). IOLM measured a lower mean ACD (−0.036 mm) and higher CCT measurements (9.296 μm). Those results were statistically different (p < 0.001 in both cases) but showed an excellent correlation coefficients (ICC = 0.994, 0.938). IOLM was able to obtain measures from all the eyes examined, while ALD did not measure in two cases with dense nuclear cataract. ALD showed spherical K measures in 7.27% of cases.Conclusion: Overall a quite good agreement between IOLM and ALD was found. ALD showed spherical keratometry measures in 7.27% of cases. IOLMaster 700 was more effective in obtaining AL measurements in eyes with dense cataracts. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the accuracy of SRK/T formula used for IOL power calculation by partial coherence interferometer in patients undergoing phacoemulsification surgery. Patients and methods: A prospective interventional clinical study included 40 eyes of 34 patients who underwent uncomplicated phacoemulsification with IOL implantation from March 2015 to March 2017. Biometries were measured using ultrasound or AL-scan and intraocular lens power was calculated using the SRK-T formula. Patients were divided into 2 groups based on device used for IOL power calculation: ALscan or ultrasound ; Axial length: >=25 mm or < 25mm; or lens opacity: Cataractous or clear lens. The mean error (ME) was calculated from the difference between the formula predicted refractive error and the actual post operative refractive error by the end of the followup (3 months postoperative). Results: Mean axial length measured preoperatively was 27.47 ± 316mm (21.55-34.05) mm. 60 percent of the patients were within 0.5 D of the predicted refractive error and 90 percent were within 1.0 D. There was no statistically significant difference in the overall performance of the SRK/T formula between the mean error when dividing the patients into 2 groups according to: device used for IOL power calculation (P= 0.274); Axial length (P= 0.46); or lens opacity (P= 0.18) in precision of predicting postoperative refraction. Conclusions : SRK/T formula helps in improvement of the accuracy of IOL power calculation and decreasing the postoperative refractive error. By using SRK/T formula, there was no statistically significant difference between the AL-scan or applanation ultrasound used in biometry. [ABSTRACT FROM AUTHOR]

Purpose To observe the variability in angle κ in pseudophakic patients and assess its correlation with optical biometry measurements and higher-order aberrations (HOAs). Setting Hanusch Hospital, Vienna, Austria. Design Prospective case series. Methods This study included patients who had cataract surgery 3 months to 1 year before study recruitment. In all cases, Purkinje meter images were taken. In addition, partial coherence interferometry measurement (IOLMaster) of the axial intraocular lens (IOL) position was performed. In a subgroup of patients, an additional Hartmann-Shack sensor measurement was taken to assess HOAs (WASCA). Results This study comprised 395 eyes of 349 patients. The mean age of the 210 women and 139 men was 74.1 years ± 8.6 (SD) (range 44 to 91 years). The mean tilt (pupillary axis) and decentration were 3.9 ± 2.3 degrees (range 0.2 to 16.2 degrees) and 0.4 ± 0.2 mm (range 0.0 to 1.7 mm), respectively. The mean angle κ was 5.2 ± 2.6 degrees (range 0.3 to 13.9 degrees), and the mean orientation of this modulus was 189.5 ± 53.2 degrees (range 25.3 to 339.7 degrees). Conclusion The variability in the angle κ was high. [ABSTRACT FROM AUTHOR]

Background: This study aimed to evaluate the prediction accuracy of postoperative refractions using partial coherence interferometry (IOL-Master) and applanation ultrasound (AL-3000) assisted with corneal topography (TMS-4) in eyes that had undergone myopic laser-assisted in situ keratomileusis (LASIK).Methods: Haigis-L formula, Koch-Maloney method using Haigis formula, Shammas clinically derived K-value (simulated keratometric value) correction (Shammas c.d.) using Haigis formula, and Shammas post-LASIK (Shammas-PL) formula were used in eyes with myopic LASIK. Constants were derived from the optimized constants in 133 virgin eyes. Refractive outcomes were determined by streak retinoscopy and subjective manifest refraction. Methods and formulas were evaluated by mean error (ME), standard deviation (SD), range of error, mean absolute error (MAE), median absolute error, 95% confidence interval of MAE, and percentage of eyes within ±0.5 diopter (D), ±1.0 D, and ±1.5 D of prediction.Results: SDs of the Haigis-L, Koch-Maloney method using the Haigis formula, Shammas c.d. using the Haigis formula, and the Shammas-PL formula using IOL-Master were 0.721, 0.695, 0.695, and 0.698; and those using AL-3000 assisted with TMS-4 were 0.782, 0.741, 0.743, and 0.778, respectively.Conclusions: No-history methods that corrected corneal power with measurements using IOL-Master were promising in myopic post-LASIK eyes, but still a gap in prediction accuracy exists between virgin eyes and post-LASIK eyes. [ABSTRACT FROM AUTHOR]