Optical Low-coherence Reflectometry Device Research Articles

Association of refractive outcome with postoperative anterior chamber depth measured with 3 optical biometers.

This study evaluated the relationship between refractive outcomes and postoperative anterior chamber depth (ACD, measured from corneal epithelium to lens) measured by swept-source optical coherence tomography (SS-OCT), optical low-coherence reflectometry (OLCR), and Scheimpflug devices under the undilated pupil. Patients undergoing cataract phacoemulsification with intraocular lens (IOL) implantation in a hospital setting were enrolled. Postoperative ACD (postACD) was performed with an SS-OCT device, an OLCR device, and a Scheimpflug device at least 1month after cataract surgery. After adjusting the mean predicted error to 0, differences in refractive outcomes were calculated with the Olsen formula using actual postACD measured from 3 devices and predicted value. Overall, this comparative case study included 69 eyes of 69 patients, and postACD measurements were successfully taken using all 3 devices. The postACD measured with the SS-OCT, OLCR, and Scheimpflug devices was 4.59 ± 0.30, 4.50 ± 0.30, and 4.54 ± 0.32mm, respectively. Statistically significant differences in postACD were found among 3 devices (P < 0.001), with intraclass correlation coefficients (ICCs) and Bland-Altman showing good agreement. No significant difference in median absolute error was found with the Olsen formula using actual postACD obtained with 3 devices. Percentage prediction errors were within ± 0.50D in 65% (OLCR), 70% (Scheimpflug), and 67% (SS-OCT) calculated by actual postACD versus 64% by predicted value. Substantial agreement was found in postACD measurements obtained from the SS-OCT, OLCR, and Scheimpflug devices, with a trend toward comparable refractive outcomes in the Olsen formula. Meanwhile, postACD measurements may be potentially superior for the additional enhancement of refractive outcomes.

Choroidal Morphologic and Vascular Features in Patients With Myopic Choroidal Neovascularization and Different Levels of Myopia Based on Image Binarization of Optical Coherence Tomography.

Purpose: To characterize the choroidal morphologic and vascular features in different levels of myopes and patients with myopic choroidal neovascularization (mCNV).Methods: A total of 148 subjects were enrolled in this cross-sectional study, including 78 low-to-moderate myopes (LMM), 53 high myopes (HM), and 17 high myopic patients with mCNV. Ocular biometrics were measured using an optical low-coherence reflectometry device. Retinal and choroidal imaging was performed using enhanced depth imaging (EDI) spectral domain optical coherence tomography (OCT). Retinal parameters including retinal thickness and retinal volume were obtained from a built-in software. Binarization technique was adopted to investigate choroidal parameters including choroidal thickness (CT), vascular area, stromal area, and choroidal vascularity index (CVI). Choroidal parameters were measured at five locations to cover as much area of choroid as possible, and their patterns of distribution were further analyzed.Results: Patients with mCNV had an atrophic retina of comparable thickness to HM (273.65 ± 17.28 vs. 276.49 ± 13.29 μm, p = 0.47), but the choroid was thinner than that of HM (153.94 ± 15.12 vs. 236.09 ± 38.51 μm, p < 0.001). Subfoveal CVI was greatest in the mCNV eyes (0.651 ± 0.009), followed by HM (0.645 ± 0.012) and LMM eyes (0.636 ± 0.012). Similar to CT, CVI was also found significantly different among these three groups at all five locations (p for trend < 0.001 for all locations). Axial length (AL) was negatively correlated with retinal volume (r = −0.236, p = 0.009), which is the only significant finding in associations between ocular factors and retinal parameters. Strong, negative correlations were identified between AL and subfoveal choroidal thickness (SFCT, r = −0.820, p < 0.001). However, AL was positively correlated with subfoveal CVI (r = 0.668, p < 0.001). CVI was greater in myopic eyes with thinner choroid (r = −0.578, p < 0.001). BCVA exhibited no significant association with CVI (r = 0.139, p = 0.092), but was negatively correlated with SFCT (r = −0.386, p < 0.001) and positively correlated with AL (r = 0.351, p < 0.001).Conclusion: Choroid in patients with mCNV was thinner yet more vascularized than that in HM and LMM subjects. CVI increased with a longer AL which was associated with a smaller SFCT, choroidal vascular area (VA), and total choroidal area (TCA). Better BCVA was achieved in subjects with thicker SFCT and shorter AL.

Comparison of corneal surgically induced astigmatism calculations based on keratometry measurements made by 2 biometric devices.

To compare calculated corneal surgically induced astigmatism (SIA) by means of anterior-based keratometry (K) and total keratometry (TK) measurements made by 2 biometric devices. Ophthalmology Department, Shaare Zedek Medical Center, Jerusalem, Israel. Retrospective, consecutive case series. The medical records of patients who had undergone cataract surgery through a 2.4 mm temporal clear corneal incision by a single surgeon between March 2018 and November 2020 were retrospectively reviewed. Patients for whom there were preoperative and postoperative K measurements assessed by 2 biometric devices, optical low-coherence reflectometry (OLCR) (Lenstar LS900, Haag-Streit, software v. eye suite i/9.1.0.0) and swept-source optical coherence tomography (SS-OCT) (IOLMaster700, Carl Zeiss Meditec AG, software v. 1.80.6.60340), were identified. Corneal SIA (mean vector value) was calculated by vector analysis for 3 groups: SS-OCT(K), SS-OCT(TK), and OLCR(K). Bivariate analyses were applied for comparisons. 147 eyes of 123 patients (73 right eyes and 74 left eyes) were enrolled in the study. The right eye corneal SIA values were 0.09 diopters (D) @ 136 degrees, 0.09 D @ 141 degrees, and 0.07 D @ 123 degrees for the SS-OCT(K), SS-OCT(TK), and OLCR, respectively. The corresponding left eye corneal SIA values were 0.13 D @ 120 degrees, 0.11 D @ 123 degrees, and 0.08 D @ 120 degrees. There were no statistically significant differences between the mean vector value and variance of the corneal SIA for the right (P = .78 and P = .65) and the left (P = .75 and P = .37) eyes of the 3 groups. Corneal SIA values were low (0.07 to 0.13 D) and similar for the SS-OCT and the OLCR biometric devices with standard K measurements. TK measurements yielded similar corneal SIA values compared with anterior corneal-based measurements.

Repeatability of 2 swept-source OCT biometers and 1 optical low-coherence reflectometry biometer.

To compare the repeatability of 2 swept-source optical coherence tomography (SS-OCT) biometers, IOLMaster 700 (biometer A, Carl Zeiss Meditec AG) and ANTERION (biometer B, Heidelberg Engineering GmbH) and 1 optical low-coherence reflectometry (OLCR) device (biometer C, LENSTAR, LS900; Haag-Streit AG). Department of Ophthalmology, Hanusch Hospital, Vienna Institute for Research in Ocular Surgery-Karl Landsteiner Institute, Vienna, Austria. Prospective study that included patients scheduled for cataract surgery. Three consecutive measurements were performed with 2 SS-OCT devices and 1 OLCR device. The repeatability of the following biometry variables was compared: keratometry, central corneal thickness, anterior chamber depth (ACD), lens thickness (LT), and axial eye length (AL). To assess the repeatability of each parameter, the within-subject SD (Sw) and coefficient of variation (CoV) were calculated. Fifty eyes of 50 patients were included. The CoV values were below 0.5 for all variables, except for ACD and LT for biometer C. The Sw values for mean keratometry were 0.018 for biometer A, 0.083 for biometer B, and 0.137 for biometer C. For the ACD, the Sw values were 0.039 and 0.004 for biometer A and biometer B, respectively, and 0.134 for biometer C. For the AL, the values were 0.006 for biometer A, 0.008 for biometer B, and 0.012 for biometer C. All biometry devices included in the analysis presented a high repeatability. The SS-OCT devices showed a higher repeatability performance compared with the OLCR device.

Features of the Choroidal Structures in Myopic Children Based on Image Binarization of Optical Coherence Tomography.

PurposeTo evaluate the features of the choroidal structures in the eyes of myopic children obtained by enhanced depth imaging optical coherence tomography (EDI-OCT).MethodsNinety-six myopic children with low to moderate myopia (spherical equivalent refractive error [SER], –5.75 to –1.00 diopter) were included in this cross-sectional study. Ocular biometrics were measured using an optical low-coherence reflectometry device. Data of the choroidal structures extracted from a 7500-µm cross-sectional arc of the choroid extending from the temporal optic disc margin, including the total choroidal area, luminal area, stromal area, and choroidal vascularity index, were determined by image binarization of the EDI-OCT. Associations between demographic factors, ocular parameters, and choroidal structures were evaluated using univariate and multiple linear regression analyses.ResultsThe study participants (mean age, 11.02 ± 1.70 years) had a mean axial length (AL) of 24.94 ± 0.70 mm. The mean total choroidal area was 2.64 ± 0.49 mm2 (luminal area, 1.68 ± 0.32 mm2; stromal area, 0.95 ± 0.19 mm2), and the choroidal vascularity index was 0.64 ± 0.03. Multiple regression analysis showed that the luminal area was significantly associated with the AL (standard β = –0.24, P = 0.022) after adjusting for sex and corneal radius (CR), whereas the stromal area (standard β = –0.30, P = 0.003) and choroidal vascularity index (standard β = 0.36, P = 0.001) were significantly associated with age after adjusting for sex, CR, and lens thickness (LT). Sex, CR, LT, and SER showed no significant association with choroidal structures after adjusting for age and AL (all P > 0.05).ConclusionsThe luminal area of the choroid tends to decrease with a longer AL, whereas the stromal area tends to decrease with increasing age in myopic children. These findings require further exploration in a longitudinal study.

Repeatability and reproducibility of optical biometry implemented in a new optical coherence tomographer and comparison with a optical low-coherence reflectometer

To examine the repeatability and reproducibility of biometry provided by a new anterior-posterior segment spectral-domain optical coherence tomography (SD-OCT) device (Revo NX) and compare it with that provided by a validated optical low-coherence reflectometry (OLCR) biometer (Lenstar LS 900). Hygeia Clinic, Gdańsk, Poland. Prospective evaluation of diagnostic test. The axial length (AL), lens thickness (LT), central corneal thickness (CCT), and anterior chamber depth (ACD) (corneal epithelium to lens) were measured in eyes of volunteers. Two skilled operators obtained 3 measurements in random order with the SD-OCT device. Repeatability was calculated for each observer, while reproducibility was assessed by a change in observer. To compare agreement between the SD-OCT device and OLCR device, the first observer took 3 measurements with both devices. The study evaluated 63 eyes of 63 volunteers. The mean AL measurement (+0.11mm±0.02 [SD]) and mean ACD measurement (0.05±0.04mm) were significantly higher with the SD-OCT device than with the OLCR device; the CCT measurements did not differ between the devices. A very strong correlation was found for all parameters, while Bland-Altman analysis showed narrow 95% limits of agreement for AL (0.06 to 0.15mm), ACD (-0.02 to 0.12mm), LT (-0.23 to 0.17mm), and CCT (-7.83 to 6.17μm). The new SD-OCT device provided repeatable and reproducible AL, ACD, LT, and CCT measurements. The results with the SD-OCT device showed strong correlations with those obtained with the OLCR device. However, the AL and ACD measurements of the 2 devices cannot be considered interchangeable.

Accuracy of Refractive Outcome Using Optical Low Coherence Reflectometry in Silicone Oil-Filled Eyes Undergoing Intraocular Lens Implantation with Silicone Oil Removal

Aim: To assess the accuracy and consistency of intraocular lens (IOL) power calculation using optical low coherence reflectometry device (OLCR), LENSTAR LS-900, in silicone oil-filled eyes undergoing combined IOL implantation and silicone oil removal (SOR). Setting: Sankara Eye Hospital, Bangalore, Karnataka, India. Design: Retrospective study. Method: This study comprised 49 silicone oil-filled eyes of 47 patients who underwent combined IOL implantation with SOR. All patients were measured with OLCR before performing phacoemulsification and IOL implantation in silicone oil mode. The predicted refraction as calculated with OLCR was correlated with the postoperative spherical equivalent. Results: The mean deviation of the spherical equivalent was −0.74 diopters (D). The mean difference between predicted refraction and postoperative spherical equivalent was −0.34 D. The mean axial length of the eyes was 23.53+1.86 (range 21.49–30.03 mm). Conclusion: OLCR is a safe device that provides precise biometry and accurate IOL power calculation in silicone oil-filled eyes.

Comparison of agreement and efficiency of a swept source-optical coherence tomography device and an optical low-coherence reflectometry device for biometry measurements during cataract evaluation.

PurposeTo compare the agreement and efficiency of a swept source-optical coherence tomography biometer, IOLMaster 700 (IOLM700), and a low-coherence optical reflectometry biometer, LENSTAR LS 900 (LS900), when acquiring biometry measurements during cataract evaluation.MethodsA retrospective chart review of biometry measurements that were performed in 64 eyes of 32 patients on the same day using the LS900 and the IOLM700. The total image acquisition time per subject was compared between the two machines using a Wilcoxon rank-sum test. Bland–Altman plots showing the mean difference and 95% limits of agreement were graphed. Intraclass correlation coefficients (ICCs) were calculated for the mean axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and two keratometry mean values (K1 and K2) that were output from each device.ResultsThe average time to complete biometry measurements in both eyes was significantly shorter for the IOLM700 compared with the LS900 (44.5±12.4 vs 168.8±67.2 seconds, P<0.001). The Bland–Altman analysis and ICCs showed high degrees of agreement for the mean biometry values (ICC: AL 0.9999, ACD 0.9993, LT 0.9571, K1 0.9922, K2 0.9926) generated by the two devices.ConclusionThere was a high level of agreement between the mean biometry output measures for IOLM700 and LS900. However, it took ~73% less time on average to acquire the images when using the IOLM700 compared with the LS900. In a busy clinic setting, use of the IOLM700 for biometry measures may save time and prove more efficient.

Comparison of preoperative and postoperative measurements of optical low-coherence reflectometry biometry and assessment of its refractive predictability.

To compare the preoperative and postoperative measurements of optical low-coherence reflectometry (OLCR) biometry and assessment of its refractive predictability. A total of 114 eyes of 102 patients who underwent cataract treatment were prospectively examined. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), K (keratometry) 1, K2, K average (KAVE) and K astigmatic (KAST) values were recorded using Lenstar LS 900 (Haag-Streit, Koeniz, Switzerland) OLCR device. The IOL (intraocular lens) power was measured based on the SRK/T formula. The cases were divided into three subgroups according to AL (Group 1: AL < 22mm, Group 2: 22mm ≤ AL < 24mm, Group 3: 24mm ≤ AL). The mean absolute error (MAE) calculated for each eye. The right eyes of 45 patients (44.1%), left eyes of 45 patients (44.1%), and both eyes of 12 patients (11.7%) were examined. The average AL in the preoperative period was 23.19 ± 1.01; it was 23.20 ± 0.99 in the postoperative period (p > 0.05). A significant deepening was detected in the postoperative ACD (preop 2.76 ± 0.38mm, postop 3.81 ± 0.46mm, p < 0.001). CCT was measured as 521.4 ± 36.3µm in the preoperative period and as 530.8 ± 42.8 (p > 0.05) µm in the postoperative period. The average mean absolute error (MAE) was measured as 0.48 ± 0.41D, whereas refractive error was - 0.081 ± 0.67D. The MAE distribution of cases was found to be ≤ 1.5D 109 (95.6%) eyes, and ≤ 2.0D in 114 (100%) eyes. MAE values according to AL of the cases were calculated as 0.71 ± 0.83D in group 1, 0.49 ± 0.43D in group 2 and 0.41 ± 0.36D in group 3 (p > 0.05). When the measurement and refractive results of the OLCR biometry were evaluated, it was observed that there was a very satisfactory result and a predictable device compatible with the current literature. The SRK/T formula, one of the new generation formulas, has shown high MAE and RE results in eyes with AL ≤ 22mm, although not statistically significant. Other new generation formulas should be tried in these eyes.

Comparison of immersion ultrasound and low coherence reflectometry for ocular biometry in cataract patients.

To compare the results of axial length (AL) biometry in cataract eyes by three methods: immersion B-ultrasound (IB) biometry, immersion A-ultrasound (IA) biometry and optical low coherence reflectometry. In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. Eighty eyes of 80 patients (39 men and 41 women) for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance (P=0.97); the mean difference in AL measurements was -0.031 mm (P=0.26; 95%CI, -0.09 to 0.02); linear regression showed an excellent correlation (r=0.98, P<0.0001). Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance (IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07); linear regression showed an excellent correlation (IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96); Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement (LoA), -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

Accuracy and feasibility of axial length measurements by a new optical low-coherence reflectometry-based device in eyes with posterior subcapsular cataract

To evaluate the feasibility and accuracy of measuring axial length (AL) by a new optical low-coherence reflectometry (OLCR)-based device in eyes with central posterior subcapsular cataract (PSC). Department of Ophthalmology, Assaf-Harofeh Medical Center, Zerifin, Israel. Retrospective case series. Consecutive cases of patients who had uneventful cataract surgery and whose preoperative AL measurements were not feasible with the partial coherence interferometry (PCI) device because of a central PSC were assessed. Preoperative AL was measured by the OLCR device and immersion ultrasound (US). Preoperative results were compared with the postoperative AL measurements obtained by the PCI. Twenty-seven patients (27 eyes) were enrolled in the study. The median difference between the OLCR and the PCI AL measurements (0.07mm) was lower than the median difference between the US and the PCI AL measurements (0.13mm)(P=.016). The ranges of the limits of agreement were 0.15mm between OLCR and PCI, and 0.88mm between US and PCI. The proportion of eyes with an AL difference of less than 0.1mm was significantly higher between the OLCR and the PCI devices (24 eyes [88.9%]) than between the US and the PCI devices (9 eyes [33.3%]) (P=.001). The OLCR-based device successfully measured the preoperative AL in all eyes with central PSC for which preoperative PCI scans were not feasible. These measurements had a high level of agreement with the postoperative AL measurements obtained by the PCI device.

Influence on intraocular lens power calculation of corneal radii measurement using an image-guided system

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. International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Prospective case series. 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. Of the 150 volunteers, 136 (mean age 39.60years±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 4formulas. 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. 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. Drs. Auffarth and Holzer received travel grants and lecture fees from Alcon Pharma GmbH and Carl Zeiss Meditec AG.

Comparison of a new image-guided system versus partial coherence interferometry, Scheimpflug imaging, and optical low-coherence reflectometry devices: Keratometry and repeatability

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. International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Prospective case series. 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. One hundred twenty-three eyes of 123 volunteers (mean age 37.9years±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). 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. None of the authors has a financial or proprietary interest in any material or method mentioned.

Biometry with a new swept-source optical coherence tomography biometer: Repeatability and agreement with an optical low-coherence reflectometry device

To assess the repeatability of a new swept-source optical coherence tomography (SS-OCT) biometer (IOLMaster 700) and evaluate the agreement with an optical low-coherence reflectometry (OLCR) biometer (Lenstar 900) in cataractous eyes. Tertiary eyecare facility. Prospective evaluation of a diagnostic test. Eyes of patients had 3 consecutive scans acquired by the same operator. The repeatability of measurements was assessed using the within-subject standard deviation and coefficient of variation (CoV). Agreement between the mean measurements of each machine was evaluated. The study comprised 100 eyes of 100 patients. The median lens thickness and axial length (AL) measurements were significantly greater (P<.001) with SS-OCT (4.29mm and 23.5mm, respectively, versus 4.25mm and 23.4mm, respectively); anterior chamber depth (ACD) was greater with OLCR (2.72mm versus 2.70mm, respectively) (P<.001). The within-subject standard deviation and CoV of the AL (0.01 and 0.05, respectively) and the ACD (0.04 and 1.22, respectively) measurements showed lower variability with SS-OCT (0.05 and 0.21, respectively, for AL; 0.06 and 1.99, respectively, for ACD) than with OLCR. Good agreement was seen for anterior segment measurements between the 2 devices. The 95% limits of agreement of most parameters fell within the test-retest variability of the parameters. The SS-OCT biometer also showed better penetration in dense posterior subcapsular cataracts, measuring AL successfully in 96% of cases. The new SS-OCT biometer showed good repeatability and agreement with the OLCR biometer. The SS-OCT biometer measured the AL with fewer dropouts compared with the OLCR even in dense cataracts. None of the authors has a financial or proprietary interest in any material or method mentioned.

Prediction accuracy of preinstalled formulas on 2 optical biometers

To evaluate how well partial coherence interferometry (PCI) (IOLMaster) and optical low-coherence reflectometry (OLCR) (Lenstar LS 900) predict postoperative refractions using only the formulas that come preinstalled on the machines. Private practice, Saint Joseph, Michigan, USA. Retrospective consecutive case series. Eyes were measured with 2 biometers before cataract surgery. Six formulas were ranked by machine. Formulas were also ranked for extremely long and short eyes by averaging the ranks of 6 statistics (mean error, mean absolute error, standard deviation [SD], maximum error, and percentage of eyes within ±0.5 diopter [D] and ±1.0 D of prediction). Formulas were ranked by the SD of the prediction errors. The OLCR device outperformed the PCI device using the preinstalled formulas. The Olsen formula performed the best (0.378) but was preinstalled on the OLCR device only. Other formulas had the following SDs (OLCR device first, PCI device second): Haigis (0.393, 0.401), Holladay 1 (0.408, 0.414), Hoffer Q (0.428, 0.432), SRK/T (0.433, 0.440), and SRK II (0.623, 0.633). Rankings for long eye were (first to last) were Olsen, Haigis, SRK/T, Hoffer Q, and Holladay 1. Rankings for short eyes were Olsen, Haigis, Holladay 1, SRK/T, and Hoffer Q. The OLCR device outperformed the PCI device using the Olsen formula. The Olsen formula also ranked first for short eyes and long eyes. Other formulas performed about the same on both machines. The SRK II formula should be avoided.

Measurement agreement between a new biometer based on partial coherence interferometry and a validated biometer based on optical low-coherence reflectometry

To evaluate the agreement of ocular measurements obtained with a new optical biometer (AL-Scan) and a previously validated optical biometer (Lenstar). Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China. Prospective observational cross-sectional study. For a comprehensive comparison between the partial coherence interferometry (PCI) device and the optical low-coherence reflectometry (OLCR) device, the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth, mean keratometry (K), astigmatism, white-to-white (WTW), and pupil diameter were measured 3 times per device in eyes with cataract. The sequence of the device was in random order. The mean values were compared and 95% limits of agreement (LoA) were assessed. Ninety-two eyes of 92 cataract patients were included. Bland-Altman analysis showed excellent agreement between the PCI device and the OLCR device for AL, CCT, ACD and aqueous depth measurements with narrow 95% LoA (-0.05 to 0.06 mm, -13.39 to 15.61 μm, -0.11 to 0.10 mm, and -0.12 to 0.10 mm, respectively), and the P values were more than 0.05. The mean K, astigmatism, and WTW values provided by the PCI device were in good agreement with the OLCR device, although statistically significant differences were detected. A major difference was observed in the pupil diameter measurement, with a 95% LoA of -0.73 to 1.21 mm. The PCI device biometer provided ocular measurements similar to those provided by the OLCR device for most parameters, especially for AL, CCT, and ACD. The pupil diameter values obtained with the PCI device were in poor agreement with the OLCR device, and these measurements should be interpreted with necessary adjustment. None of the authors has a proprietary or financial interest in any material or method mentioned.

Comparability of anterior chamber depth measurements with partial coherence interferometry and optical low-coherence reflectometry in pseudophakic eyes

To assess whether anterior chamber depth (ACD) measurements in pseudophakic eyes obtained with partial coherence interferometry (PCI) and optical low-coherence reflectometry (OLCR) devices can be used interchangeably. Vienna Institute for Research in Ocular Surgery, A Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria. Prospective case series. The ACD measurements in 1 eye of each pseudophakic patient were performed with the PCI-based ACMaster device and the OLCR-based Lenstar LS900 device at least 1 day postoperatively. The study comprised 65 eyes of 65 patients with a mean age of 71.7 years ± 9.0 (SD) (range 39 to 91 years). In 15 eyes, no valid ACD readings could be obtained with the OLCR device. No obvious reason for these measurement failures was identified; however, tear-film alterations shortly after surgery were suspected. No significant difference in the mean ACD in the remaining 50 eyes was found between PCI measurements (5019 ± 660 μm; range 4008 to 6181 μm) and OLCR measurements (5015 ± 663 μm; range 4017 to 6163 μm) (P = .06). Three (6%) of 50 measurements were not within the 95% limits of agreement in the Bland-Altman analysis. Pseudophakic ACD measurements with the PCI and OLCR devices can be used interchangeably. The OLCR device proved to be more user-friendly and faster; however, in a substantial number of eyes, no usable values were obtainable. No author has a financial or proprietary interest in any material or method mentioned.

Ocular biometric characteristics during the menstrual cycle.

PurposeTo determine the ocular biometric characteristics during the menstrual cycle using the optical low-coherence reflectometry (OLCR) biometry.MethodsTwenty-two healthy women between the ages of 19 and 36 years with regular menstrual cycles were enrolled in this prospective study. Subjects with irregular menstrual cycles, those taking contraceptive pills, those with a history of ocular surgery or trauma, and women unable to cooperate with the ocular biometry device were excluded from this study. A complete ophthalmic examination was performed between 8.30 and 10.30 am for all participants. Also, central corneal thickness, axial length, anterior chamber depth, lens thickness, and keratometric measurements were made at the same time using the OLCR device. Measurements were taken at the beginning of the cycle (1–3 days), at ovulation (12–16 days), and at the end of the cycle (26–32 days).ResultsThe mean age of the participants was 22.86±4.22 (range: 18–36) years. The difference in central corneal thickness, axial length, anterior chamber depth, lens thickness, and keratometry values were not statistically significant during the menstrual cycle.ConclusionThe ocular biometric parameters did not significantly vary during the menstrual cycle according to the OLCR biometry.

Comparison of anterior segment measurements with optical low-coherence reflectometry and rotating dual Scheimpflug analysis

To compare the anterior segment measurements obtained with optical low-coherence reflectometry (OLCR) (Lenstar LS 900, version 2.1.1) and rotating dual Scheimpflug analysis (Galilei G1, version 3). Private practice, Policlinic Lleida, Lleida, Spain. Prospective comparative observational study. The following measurements were performed in patients requiring a preoperative study for a refractive procedure or cataract surgery and healthy volunteers from the clinic's staff: central corneal thickness (CCT), anterior chamber depth (ACD), horizontal limbal distance (white-to-white distance [WTW]), pupil diameter, keratometry (K) readings at the steepest meridian (steep K) and the flattest meridian (flat K), corneal astigmatism power, and plus astigmatic cylinder. Measurements were taken using the OLCR device and rotating dual Scheimpflug analyzer. The main outcome measure was the degree of agreement between steep K, flat K, astigmatism power, cylinder axis, CCT, ACD, WTW, and pupil diameter measurements. The study enrolled 100 eyes of 100 subjects. Steep K, flat K, corneal astigmatism power, cylinder axis, and WTW measurements with the OLCR device and Scheimpflug analyzer showed narrow 95% limits of agreement (LoA), which implies good agreement (P>.05, Bland-Altman plot analysis). In contrast, the range and 95% LoA for CCT, ACD, and pupil diameter values were statistically significantly different (P<.05, Bland-Altman plot analysis). In clinical practice, the OLCR device and the rotating dual Scheimpflug analyzer system can be used interchangeably for WTW measurements and K readings but not for CCT, ACD, and pupil diameter values. No author has a financial or proprietary interest in any material or method mentioned.

The Effects of Smoking on Anterior Segment Parameters, Retinal Nerve Fiber Layer, and Pupillary Functions

Address for Correspondence/Yazisma Adresi: Bengu Ekinci Koktekir MD, Selcuk University School of Medicine, Department of Ophthalmology, Konya, Turkey Gsm: +90 532 353 27 16 E-mail: benguekinci@hotmail.com Received/Gelis Tarihi: 23.06.2013 Accepted/Kabul Tarihi: 23.07.2013 This study was presented as free paper presentation in the 46th Annual Turkish Ophthalmological Society Meeting, Antalya, Turkey, 2012 Objectives: To evaluate the alterations in the anterior segment parameters, retinal nerve fiber layer, and pupillary functions in smokers. Materials and Methods: In this case-control study, 45 eyes of 45 smokers and 45 eyes of 45 non-smoker control subjects were evaluated. All patients underwent measurement of anterior segment parameters with optical low coherence reflectometry (OLCR), mesopic and photopic pupillary diameter with an aberrometer device, retinal nerve fiber layer thickness with optical coherence tomography, and dry-eye assessment with Schirmer’s test. The results were compared with independent t-test by SPSS 16.0 Inc., and a p-value lower than 0.05 was determined as significant. Results: There was a significant difference between both groups in terms of mesopic pupil diameters that were measured with both OLCR and aberrometer device (p=0.03 and 0.02, respectively). Schirmer scores were also significantly decreased in smokers (p=0.001). The other measured parameters demonstrated no difference between smokers and non-smokers (p>0.05 for all). Conclusion: Smoking may affect pupillary functions, especially the mesopic pupillary diameter, and may cause a deficiency in pupil response under dark circumstances. (Turk J Ophthalmol 2014; 44: 11-4)