Assessment of the Feasibility of Using Noninvasive Wearable Biometric Monitoring Sensors to Detect Influenza and the Common Cold Before Symptom Onset.

Importance: Currently, there are no presymptomatic screening methods to identify individuals infected with a respiratory virus to prevent disease spread and to predict their trajectory for resource allocation. Objective: To evaluate the feasibility of using noninvasive, wrist-worn wearable biometric monitoring sensors to detect presymptomatic viral infection after exposure and predict infection severity in patients exposed to H1N1 influenza or human rhinovirus. Design, Setting, and Participants: The cohort H1N1 viral challenge study was conducted during 2018; data were collected from September 11, 2017, to May 4, 2018. The cohort rhinovirus challenge study was conducted during 2015; data were collected from September 14 to 21, 2015. A total of 39 adult participants were recruited for the H1N1 challenge study, and 24 adult participants were recruited for the rhinovirus challenge study. Exclusion criteria for both challenges included chronic respiratory illness and high levels of serum antibodies. Participants in the H1N1 challenge study were isolated in a clinic for a minimum of 8 days after inoculation. The rhinovirus challenge took place on a college campus, and participants were not isolated. Exposures: Participants in the H1N1 challenge study were inoculated via intranasal drops of diluted influenza A/California/03/09 (H1N1) virus with a mean count of 106 using the median tissue culture infectious dose (TCID50) assay. Participants in the rhinovirus challenge study were inoculated via intranasal drops of diluted human rhinovirus strain type 16 with a count of 100 using the TCID50 assay. Main Outcomes and Measures: The primary outcome measures included cross-validated performance metrics of random forest models to screen for presymptomatic infection and predict infection severity, including accuracy, precision, sensitivity, specificity, F1 score, and area under the receiver operating characteristic curve (AUC). Results: A total of 31 participants with H1N1 (24 men [77.4%]; mean [SD] age, 34.7 [12.3] years) and 18 participants with rhinovirus (11 men [61.1%]; mean [SD] age, 21.7 [3.1] years) were included in the analysis after data preprocessing. Separate H1N1 and rhinovirus detection models, using only data on wearble devices as input, were able to distinguish between infection and noninfection with accuracies of up to 92% for H1N1 (90% precision, 90% sensitivity, 93% specificity, and 90% F1 score, 0.85 [95% CI, 0.70-1.00] AUC) and 88% for rhinovirus (100% precision, 78% sensitivity, 100% specificity, 88% F1 score, and 0.96 [95% CI, 0.85-1.00] AUC). The infection severity prediction model was able to distinguish between mild and moderate infection 24 hours prior to symptom onset with an accuracy of 90% for H1N1 (88% precision, 88% sensitivity, 92% specificity, 88% F1 score, and 0.88 [95% CI, 0.72-1.00] AUC) and 89% for rhinovirus (100% precision, 75% sensitivity, 100% specificity, 86% F1 score, and 0.95 [95% CI, 0.79-1.00] AUC). Conclusions and Relevance: This cohort study suggests that the use of a noninvasive, wrist-worn wearable device to predict an individual's response to viral exposure prior to symptoms is feasible. Harnessing this technology would support early interventions to limit presymptomatic spread of viral respiratory infections, which is timely in the era of COVID-19.

Influence of Artificial Tears on Keratometric Measurements in Cataract Patients.

PURPOSE: To assess the influence of artificial tears of different viscosity on K-readings prior to cataract surgery. DESIGN: Prospective randomized crossover, before-and-after clinical study. METHODS: Setting: Department of Ophthalmology, Medical University of Vienna. PATIENT POPULATION: A total of 123 eyes of 80 patients prior to cataract surgery were assigned to 2 groups based on normal and dry eyes. INTERVENTION: Two native baseline keratometries were followed by instillation of either high- or low-viscosity eye drops. Keratometry was repeated 30 seconds, 2 minutes, and 5 minutes after instillation. MAIN OUTCOME MEASURES: Influence of eye drops of different viscosity in normal and dry eyes on short time K-readings. RESULTS: Repeatability between native baseline measurements was high (standard deviation = 0.02 mm in normal and in dry eyes). In normal and dry eyes, a statistically significant increase in measurement variability after instillation of both low-viscosity and high-viscosity eye drops was observed (P < .01). Measurement variability was most pronounced between baseline measurement and 30 seconds and diminished over time. Variability of K-readings appeared higher in dry eyes compared with normal eyes. Astigmatism changed more than 0.5 diopters in 13.2% of normal eyes and 34.4% in dry eyes using eye drops of high viscosity. CONCLUSION: Tear film-stabilizing eye drops prior to keratometry measurements influenced K-readings significantly, especially in dry eyes. A time period of more than 5 minutes should be allowed to pass after instillation of eye drops. The higher the viscosity of the eye drops, the stronger the influence and the longer its persistence.

Competition of onion genotypes in the soil and climatic conditions of Guarapuava, State of Paraná

The use of genotypes more adapted to climatic conditions can contribute to increase the yield of onion producers. The goal of this study was to evaluate the agronomic performance of 15 onion genotypes in the soil and climatic conditions of Guarapuava, state of Paraná. The study was conducted in the experimental area of Horticulture, Cedeteg campus, Universidade Estadual do Centro-Oeste (UNICENTRO), Guarapuava, state of Paraná, Brazil, from July to November 2018. The experimental design used was randomized blocks, with four replications, and the treatments consisted of four commercial cultivars Optima F1, Bella Dura, Sirius F1, Soberana F1 and eleven experimental genotypes N1, N2, N3, N4, N5, N6, N7, N8, N9, AF4241 and AF4243. Biometric characteristics of the plants, production components and early flowering were evaluated. Plants presented between 6 and 9 leaves, in which N1, N3, N4 and N6 had less than 7 leaves, differing statistically from the others. The cultivar Optima F1 and the genotypes N2, N3, N5, N6, N7 and N8 presented the tallest plants, with 66.1 to 76.0 cm. The pseudostem diameter did not differ significantly between genotypes, showing values between 15.2 and 20.4 mm. Total productivity was higher in genotypes N2, N6, N5, N4, N3, N7 with values from 43.6 to 50.3 t ha-1. The highest average bulb mass was found in N2, N4, N6, Sirius F1, Optima F1 and Soberana F1

Agreement Between Two Optical Biometers Based on Large Coherence Length SS-OCT and Scheimpflug Imaging/Partial Coherence Interferometry.

PURPOSE: To evaluate the agreement between measurements obtained with a new optical biometer (Argos; Movu Inc) using large coherence length swept-source optical coherence tomography (SS-OCT) and those obtained with an optical biometer with a rotating Scheimpflug camera, combined with partial coherence interferometry (PCI) (Pentacam AXL; Oculus Optikgeräte GmbH) in adults. METHODS: The following measurements were examined and evaluated: axial length, central corneal thickness (CCT), anterior chamber depth (ACD), mean keratometry, J0 and J45 vectors, and corneal diameter. Measurements with the two biometers were conducted in triplicate per instrument in a random order by the same examiner. Paired t tests were employed to compare the difference between the two devices. The Bland-Altman method was implemented to assess their agreement. RESULTS: A total of 145 patients were enrolled in the study. The differences between the Scheimpflug/PCI-based biometer and the SS-OCT biometer were as follows: -0.02 ± 0.05 mm for axial length, 1.15 ± 5.79 µm for CCT, -0.04 ± 0.04 mm for ACD, -0.28 ± 0.16 diopters (D) for mean keratometry, 0.01 ± 0.11 D for J0, -0.02 ± 0.10 D for J45, and -1.03 ± 0.62 mm for corneal diameter. Bland-Altman plots showed narrow ranges in axial length, CCT, ACD, mean keratometry, and J0 and J45, which implied excellent agreement between the two biometers. Corneal diameter displayed poor agreement, with a 95% limits of agreement ranging from -2.25 to 0.19 mm. CONCLUSIONS: Excellent agreement was established between the measurements provided by the new optical biometer based on SS-OCT and the optical biometer using Scheimpflug imaging and PCI, except for corneal diameter. [J Refract Surg. 2020;36(7):459-465.].

Evaluation of total corneal power measurements with a new optical biometer.

PURPOSE: To evaluate the repeatability and validity of total corneal power measurements (total keratometry [TK]) obtained with a recently introduced optical biometer (IOLMaster 700, Carl Zeiss Meditec AG) to a Scheimpflug device (Pentacam, Oculus). SETTING: Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany. DESIGN: Prospective randomized controlled trial. METHODS: The inclusion criteria were a corneal astigmatism of 3.00 diopters (D) or less, no previous ocular surgery, no known corneal irregularities, and no known dry eyes. All eyes were measured 3 times using the optical biometer and the Scheimpflug device. The results were statistically compared using Bland-Altman, within-subject SD, and astigmatism vector analysis. RESULTS: Ninety-three eyes of 93 subjects were included. Overall, the repeatability of all eyes measured was 0.42 for standard K, 0.40 for TK, 0.45 for total corneal refractive power (TCRP), 0.43 for true net power (TNP), and 0.39 for simulated K. Bland-Altman analysis showed no significant difference between the optical biometer's TK compared with standard K and the Scheimpflug device's simulated K, TNP, and TCRP, the P value exceeding .05 in each case. A difference of >0.50 diopters between astigmatism measurements between TK and TCRP was found in 10 cases compared with standard K and TNP with 0 and 2 cases. CONCLUSIONS: Repeatability of both devices was high, although measurements of meridian showed a great variability, suggesting that numerous measurements are needed to enhance accuracy. TCRP measurements between recently introduced TK and TCRP cannot be used interchangeably. Future studies are necessary to evaluate which measurement will result in a better outcome when respective measurements are used for toric intraocular lens calculations.

Axial length measurement and detection rates using a swept-source optical coherence tomography-based biometer in the presence of a dense vitreous hemorrhage.

PURPOSE: To evaluate axial length (AL) measurements and detection rates using a swept-source optical coherence tomography (SS-OCT) biometer (OA-2000) compared with the IOLMaster, LENSTAR, and ultrasound (US) measurements in eyes with vitreous hemorrhage. SETTING: Eye Hospital of Wenzhou Medical University, China. DESIGN: Comparative evaluation of a diagnostic test or technology. METHODS: Patients were adults with vitreous hemorrhage in one or both eyes. Lens Opacities Classification System III was used to determine they type and severity of cataract and the Forrester system was used to classify the grade of vitreous hemorrhage. The AL measurement was taken with the OA-2000, IOLMaster (v5.4), and LENSTAR (v2.1), and with US (Axis-II). The Bland-Altman test was used to assess the agreement between devices. RESULTS: Forty eyes were scanned with each of the 4 biometers. For Forrester grade III, the detection rate was 100%, 41.7%, and 41.7% with the OA-2000, IOLMaster, and LENSTAR, respectively. For Forrester grades I and II, the detection rate was 46.4%, 3.57%, and 3.57% with the OA-2000, IOLMaster, and LENSTAR, respectively. The detection rate with US was 100% for all grades. The Bland-Altman limits of agreement between the 4 biometers indicated an excellent agreement: OA-2000 vs IOLMaster (95% limits of agreement -0.15 to 0.05 mm), OA-2000 vs LENSTAR (-0.04 to 0.12 mm), and OA-2000 vs US (-0.3 to 0.56 mm). CONCLUSIONS: In vitreous hemorrhage, the detection rate with the SS-OCT OA-2000 biometer was better than that with the IOLMaster and LENSTAR. In cases in which all biometers were able to acquire an AL measurement an excellent agreement was found.

Comparison of formula accuracy for intraocular lens power calculation based on measurements by a swept-source optical coherence tomography optical biometer.

PURPOSE: To analyze the results of intraocular lens (IOL) power calculation using measurements by a swept-source optical coherence tomography (SS-OCT) optical biometer. SETTING: IRCCS G.B. Bietti Foundation, Rome, Italy. DESIGN: Evaluation of a diagnostic test instrument. METHODS: Preoperative measurements by the OA-2000 (Tomey Inc.) were taken in a consecutive series of patients undergoing cataract surgery with one IOL model (AcrySof SN60WF; Alcon Laboratories, Inc.). Measurements were entered into the following formulas: Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Holladay 1, Holladay 2, Holladay 2 with axial length adjustment, Kane, Olsen, Panacea, SRK/T, T2, and VRF. When refraction was measured at 1 month postoperatively, the mean arithmetic prediction error, the median absolute error (MedAE), and the percentage of eyes with a error of ±0.50 D or less were calculated after constant optimization. RESULTS: We enrolled 150 eyes. All formulas yielded excellent outcomes. The MedAE ranged between 0.200 D and 0.259 D, with a statistically significant difference among formulas (P = .0004). The lowest MedAE values were obtained with the Barrett, EVO, Kane, Olsenstandalone, Radial Basis Function (RBF), and T2 formulas. The percentage of eyes with a prediction error of ±0.50 D or less ranged between 80.00% and 90.67%, with a statistically significant difference (P < .0001). The Barrett, EVO, Holladay 2 with axial length adjustment, Kane, RBF, and T2 achieved the highest percentages (≥88%). CONCLUSIONS: Measurements provided by the SS-OCT optical biometer enable accurate IOL power calculation because all formulas yielded a prediction error within 0.50 D in at least 80% of eyes.

[Comparison of keratometric measurements obtained by the Verion image guided system with the IOLMaster and the Pentacam before cataract extraction surgery].

Objective: To compare the keratometric measurements of the Verion image guided system with the partial coherence interferometry (IOLMaster700) and the scheimpflug corneal topography (Pentacam). Methods: In this cross-sectional study, 146 eyes of 88 patients [mean age, (69±10) years; 62 eyes of male patients and 84 eyes of female patients] with cataract were examined before cataract extraction and IOL implantation surgery in the Tenth People's Hospital Affiliated to Tongji University from January 2016 to March 2017. Corneal curvature values acquired by the Verion optical imaging system were compared with the IOLMaster700 and the Pentacam. Keratometric data, magnitude of astigmatism, and steep astigmatic axis measurements from all three instruments were also compared. According to the steep axis of astigmatism, the eyes were divided into groups of with the rule (WTR), against the rule (ATR), and oblique astigmatism. The parameter differences between the Verion and the other devices in the three groups were analyzed. The data were evaluated using repeated measures analysis of variance and Bland-Altman plots. Results: The values of steep keratometry (Ks) of the Verion, IOLMaster700, and Pentacam were (44.60±1.32), (44.73±1.37), (44.43±1.35) D, respectively. The values of flat keratometry (Kf) of the Verion, IOLMaster700, and Pentacam were (43.51±1.41), (43.51±1.52), (43.40±1.45) D, respectively. The values of mean keratometry (Km) of the Verion, IOLMaster700, and Pentacam were (44.60±1.32), (44.12±1.35), (43.92±1.34) D, respectively. The values of astigmatism magnitude were (1.09±0.87), (1.24±1.02), (1.04±0.80) D, respectively. The F values were 1.81, 0.31, 0.93 and 2.22 in relation to Ks, Kf, Km and corneal astigmatism magnitude among the three instruments, respectively (all P>0.05). The 95% confidence intervals of Kf, Ks and astigmatism magnitude between the Verion and the other two devices were -1.10 to 0.80 D, -0.55 to 0.88 D; -1.10 D to 1.10 D, -0.80 to 1.04 D; -1.21 to 0.90 D, -0.92 to 1.02 D. The outcomes were considered acceptable. There were no statistically differences in steep astigmatic axis measurements between the Verion and the other two instruments among the WTR (62 eyes), ATR (45 eyes) and oblique (15 eyes) groups (F=0.63, 0.37; P=0.54, 0.72, respectively). Conclusions: The Verion image guided system is a reliable system for the measurement of keratometry values and astigmatism. The keratometric power, magnitude and steep axis of astigmatism have no significant difference, and there is a good agreement among the Verion, IOL Master 700, and Pentacam. (Chin J Ophthalmol, 2020, 56: 47-52).

Comparison of Preoperative Parameter Measurements Using an Optical Biometer, Automated Keratometer, and a Placido-Based Topographer Module.

OBJECTIVES: To assess the agreement of corneal power, corneal astigmatism, axis location, and astigmatic vector component measurements using a Lenstar LS900, a T-cone add-on, and an ARK 1S autorefractor, furthermore, to assess instrument agreement in a subset of astigmatic eyes. METHODS: Retrospective analysis of keratometric readings from 3 instruments for 66 eyes undergoing cataract surgery at the Maryland Veterans Affairs Medical Center from November 2014 to 2015. Agreement in corneal power, mean corneal power, axis location, and astigmatic vector components (J0, J45) between devices was evaluated. Comparability was assessed using intraclass correlation, analysis of variance (ANOVA) one-way analysis, Bland-Altman analysis, and power vector analysis. Intraclass correlation was then assessed for a subset of 42 eyes with corneal astigmatism greater than or equal to 1 D. RESULTS: The intraclass correlation between instruments was 0.941 for corneal power, 0.788 for corneal astigmatism, 0.932 for J0, and 0.809 for J45. The ANOVA one-way repeated P values comparing Kf, Ks, Km, corneal astigmatism, axis location, J0, and J45 were all greater than 0.05. Power vector analysis showed nearly all values between instruments to be within ±0.5 D. Finally, the intraclass correlation between instruments in eyes with ≥1 D of corneal astigmatism as measured by the T-cone was 0.946 for corneal power, 0.837 for corneal astigmatism, 0.948 for J0, and 0.950 for J45. CONCLUSIONS: The high level of agreement between all devices indicates the instruments may be used interchangeably. Our data suggest that this may also be true for the subset of eyes with greater than or equal to 1 D in astigmatism, highlighting the toric intraocular lens population.

Intrasession Repeatability of Biometric Measurements Obtained with a Low-Coherence Interferometry System in Pseudophakic Eyes.

Purpose: To evaluate the intrasession repeatability of the biometric measurements obtained with a low-coherence reflectometry optical biometer in pseudophakic eyes implanted with two different types of intraocular lens (IOL).Methods: Prospective, single-center, comparative study including 69 eyes of 69 patients with ages ranging from 51 to 92 years. Previous uncomplicated cataract surgery had been performed in all patients 1 to 2 months before measurements, with implantation of the Acrysof SN60WF IOL in 35 eyes (35 patients, group 1) and the IOL Akreos MI60 in 34 eyes (34 patients, group 2). A complete postoperative ophthalmological examination was performed including three consecutive measurements with the "Aladdin" system from (Topcon, Japan). Intrasession repeatability of axial length (AXL), anterior chamber depth (ACD) and IOL thickness (IOLT) were assessed with the within-subject standard deviation (Sw), intraobserver precision (1.96 × Sw), coefficient of variation (CV) and intraclass correlation coefficient (ICC). Results: The Sw for AXL measurements was 0.03 and 0.05 mm in groups 1 and 2, respectively, with ICC of 1.000 and 0.999 (CV: 0.14% and 0.22%) (p ≤ 0.031). Concerning pseudophakic ACD, the Sw was 0.03 and 0.09 mm in groups 1 and 2, respectively, with ICC of 0.992 and 0.956 (CV: 0.55% and 1.75%) (p ≤ 0.021). The variability of IOLT measurements was high in both groups, with Sw of 0.12 and 0.29 mm for groups 1 and 2 (p = .008), respectively, and ICC of 0.065 and 0.770 (CV: 20.84% and 62.39%).Conclusions: The optical biometer "Aladdin" (Topcon, Japan) provides consistent measurements of AXL and ACD in pseudophakic eyes. However, there is a limitation in the consistency of IOLT measurements that should be investigated further.

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

PURPOSE: 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). SETTING: Hygeia Clinic, Gdansk, Poland. DESIGN: Prospective evaluation of diagnostic test. METHODS: 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. RESULTS: The study evaluated 63 eyes of 63 volunteers. The mean AL measurement (+0.11 mm ± 0.02 [SD]) and mean ACD measurement (0.05 ± 0.04 mm) 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 0.15 mm), ACD (-0.02 to 0.12 mm), LT (-0.23 to 0.17 mm), and CCT (-7.83 to 6.17 µm). CONCLUSIONS: 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.

Predictive value of intracrystalline interphase point measured by optical low-coherence reflectometry for the estimation of the anatomical position of an intraocular lens after cataract surgery.

PURPOSE: To investigate the predictive value of the intracrystalline interphase point (ICIP) measured with optical low-coherence reflectometry (OCLR) to estimate the final lens position (FLP) of an intraocular lens (IOL) after cataract surgery. SETTING: Alcañiz Hospital, Teruel, Spain. DESIGN: Single-center retrospective descriptive study. METHODS: Patients undergoing cataract surgery were enrolled. They were grouped according to the IOL implanted as follows: Group 1, Acrysof IQ aspheric SN60WF IOL (77 eyes); Group 2, enVista MX60 IOL (71 eyes); Group 3, CT Asphina 409 IOL (44 eyes). An OCLR-based biometer (Lenstar LS 900 system) was used for biometric measurements preoperatively and at 4 to 5 weeks postoperatively. RESULTS: The study comprised 192 eyes of 174 patients (mean age: 76.4 years). One hundred seventy eyes (88.5%) eyes showed an absolute refractive prediction error (ARPE) less than 0.50 diopters (D). The mean ARPE was 0.25 D ± 0.21 (SD). Significantly higher FLP values were found in Group 2 compared with the other two groups (P < .001). Significantly lower ICIP values were found in the eyes with an ARPE of 0.50 D or more compared with eyes that had an ARPE less than 0.50 D in Group 1 (P = .042) and Group 2 (P = .023). The correlation of the FLP with the ICIP was good in all three groups (r ≥ 0.74, P <.001). Three linear expressions were obtained to predict the FLP from the ICIP and other preoperative data (R2: 0.85, 0.69, and 0.49 in Groups 1, 2, and 3, respectively). CONCLUSIONS: The position of the ICIP measured with OCLR correlated with the FLP after cataract surgery, and it can be used to optimize IOL power calculations.

Agreement of ocular biometry measurements between 2 biometers.

PURPOSE: To establish the agreement of routine measurements taken before cataract surgery between the Aladdin biometer, which is based on optical low-coherence interferometry (OLCI), and the Lenstar biometer, which is based on optical low-coherence reflectometry (OLCR). SETTING: Virginia Eye Consultants, Norfolk, Virginia, USA. DESIGN: Prospective case series. METHODS: Biometry parameters in the same eye were measured using the OLCI biometer and the OLCR biometer at separate preoperative visits. Measured parameters included axial length (AL), anterior chamber depth (ACD), keratometry (K) values (flat K, steep K, steep K axis), lens thickness, central corneal thickness (CCT), and the white-to-white (WTW) distance. Adverse events were monitored. RESULTS: Data were collected for 101 eyes (65 right eyes) of 101 patients (mean age 67.9 years ± 7.2 [SD]). The mean values measured by the OLCI biometer and OLCR biometer, respectively, were as follows: AL, 23.88 ± 1.23 mm and 23.89 ± 1.23 mm; ACD, 3.24 ± 0.36 mm and 3.25 ± 0.37 mm; flat K, 43.63 ± 1.65 diopters (D) and 43.61 ± 1.67 D; steep K, 44.59 ± 1.76 D and 44.61 ± 1.77 D; lens thickness, 4.61 ± 0.39 mm and 4.45 ± 0.45 mm; CCT, 0.55 ± 0.04 mm and 0.55 ± 0.04 mm; and WTW distance, 11.63 ± 0.41 and 12.03 ± 0.49 mm. There was a high correlation between all parameter measurements obtained by the 2 devices. No adverse events occurred. CONCLUSION: The measurements of the OLCI biometer were as reliable and reproducible as those of a leading biometer on the market, with the former having the advantage of an incorporated full corneal topographer.

Comparative analysis of 2 swept-source optical coherence tomography biometers.

PURPOSE: To report the level of agreement, repeatability, and correlation of axial length (AL), mean keratometry, central corneal thickness, anterior chamber depth, lens thickness, and corneal diameter measurements of 2 swept-source optical coherence tomography (SS-OCT) biometers, the IOLMaster 700 (reference biometer) and the Argos (new biometer). SETTING: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. DESIGN: Retrospective case series. METHODS: Each patient had SS-OCT biometry with the reference biometer and new biometer. In addition to reporting the statistical results derived from both eyes, this study included a subgroup analysis of right eyes and left eyes. The level of agreement between the biometers was represented with the Bland-Altman method. Power vector analysis of the J0 (Jackson cross-cylinder, axes at 0 degrees and 90 degrees) and J45 (Jackson cross-cylinder, axes at 45 degrees and 135 degrees) vectorial components of astigmatism was performed. Internal consistency was assessed with the Cronbach α coefficient of reliability. The dispersion of probability distribution was computed with the coefficient of variation. The intraoperator repeatability was calculated using the intraclass correlation coefficient (ICC). RESULTS: The study comprised 112 patients (218 eyes). There was a statistically significant difference between the 2 biometers in all measurements (P < .05) except AL. The level of correlation between the reference biometer and the new biometer was very high for all the parameters except corneal diameter, and the agreement was high. The ICC and internal consistency were excellent with both biometers. CONCLUSION: The new biometer provided good agreement and repeatability compared with the reference biometer.

Ocular measurements of a swept-source biometer: Repeatability data and comparison with an optical low-coherence interferometry biometer.

PURPOSE: To assess the repeatability of a swept-source biometer in phakic and pseudophakic patients, including astigmatism analysis, and to compare measurement data with those obtained by an optical low-coherence interferometry method. SETTING: Borsod-Abaúj-Zemplén County Central Hospital and University Teaching Hospital, Miskolc, Hungary. DESIGN: Evaluation of diagnostic technologies. METHODS: One eye of each patient was examined with the Argos and Aladdin devices. With the Argos, three repeated measurements were performed. Biometric parameters and cross-cylinder power vector components of astigmatism were assessed. Descriptive and repeatability data of the Argos were observed, and Bland-Altman plots were created. RESULTS: The study comprised 96 eyes (50 phakic and 46 pseudophakic) of 96 patients (mean age 69.22 years and 71.14 years, respectively). The two devices showed a significant difference regarding astigmatism and corneal diameter in the phakic group (measured larger by Argos, P < .05). In the pseudophakic group, only the corneal diameter data were significantly different (measured larger by Argos, P = .02). No other statistically significant differences were observed in either group. An excellent intraclass correlation coefficient (ICC) was reported on the Argos device in the case of all measured parameters except for the diopter values of astigmatism and the vector values of the astigmatism in the phakic group. In the pseudophakic group, the ICC was moderate in the case of anterior chamber depth (ACD) and good in the case of astigmatism and vectorial data. CONCLUSIONS: The repeatability data regarding the Argos biometer were excellent for all parameters except astigmatism data in both groups and ACD readings in the pseudophakic group. However, only a limited agreement was observed between these devices in both groups.

Clinical Evaluation of a New Swept-Source Optical Coherence Biometer That Uses Individual Refractive Indices to Measure Axial Length in Cataract Patients.

BACKGROUNDS: Although the OCT biometer using individual refractive index is available, comparisons of measurement value and intraocular lens (IOL) power calculation error with other SS-OCT biometers are not known. OBJECTIVES: To compare the new SS-OCT biometer ARGOS (OCTB1), which uses individual refractive indices to measure axial length, with the IOLMaster 700 (OCTB2) and OA-2000 (OLCR), which use equivalent refractive index. METHOD: Six hundred and twenty-two eyes of 622 patients who had been diagnosed with cataract were enrolled in the study. Among the 158 eyes that had undergone cataract surgery, the postoperative refractive error was evaluated using the Haigis formula. RESULTS: The axial length measured by the OCTB1 showed a proportional bias in comparison with the other two biometers and a fixed bias in eyes with an axial length ≥26 mm. No significant difference was found in the median absolute refractive prediction error (p = 0.3278). However, in eyes with an axial length ≥26 mm, the OCTB1 showed myopic error compared with the other two biometers (p < 0.0001). CONCLUSIONS: In eyes with long axial length, when the conventional IOL calculation was optimized with the equivalent refractive index-based instrument, we need to consider that IOL calculation using OCTB1 tends to cause slightly myopic refractive prediction error.

Comparison of anterior segment measurements obtained using a swept-source optical coherence tomography biometer and a Scheimpflug-Placido tomographer.

PURPOSE: To assess the repeatability and agreement of anterior segment measurements between an optical biometer (IOLMaster 700) using swept-source optical coherence tomography and a Scheimpflug-Placido tomographer (Sirius) in patients scheduled for corneal refractive surgery. SETTING: Eye Hospital of Wenzhou Medical University, Zhejiang, China. DESIGN: Prospective case series. METHODS: The parameters, including the central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth, keratometry (K) values, astigmatism, J0 (Jackson cross-cylinder with axes at 180 degree and 90 degrees) and J45 vectors (Jackson cross-cylinder with axes at 45 degrees and 135 degrees), and horizontal corneal diameter, were measured 3 times per instrument. The intraobserver repeatability was assessed using test-retest repeatability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC). Paired t tests were used to compare the difference between the 2 methods. Agreement was evaluated using Bland-Altman analyses. RESULTS: The study enrolled 100 right eyes. All measurements of the 2 devices showed high repeatability. The CoV of all measured parameters was less than 0.93 and the ICC value was more than 0.85. The paired t test did not show a significant difference in CCT, astigmatism, J0 or J45 vector. The mean ACD and aqueous depth were statistically lower with the optical biometer; however, the 95% limits of agreement (LoA) were low (from -0.20 to -0.03 mm). The K and corneal diameter values obtained using the optical biometer were higher by 0.1 diopter and 0.1 mm, respectively, but with narrow 95% LoA. CONCLUSIONS: The optical biometer and the Scheimpflug-Placido tomographer showed high repeatability for all anterior segment measurements. The measured parameters showed good agreement and could be used interchangeably.

Comprehensive Comparison of Axial Length Measurement With Three Swept-Source OCT-Based Biometers and Partial Coherence Interferometry.

PURPOSE: To compare axial length measurements (and failure rate) of three swept-source optical coherence tomography (SS-OCT)-based biometers: IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany), OA-2000 (Tomey, Nagoya, Japan), and Argos (Movu Inc., Komaki, Japan) to those provided by a partial coherence interferometry (PCI)-based optical biometer (IOLMaster v5.4 [Carl Zeiss Meditec]). METHODS: A total of 119 patients (171 eyes) undergoing cataract surgery were enrolled. Axial length was measured with the four biometers in a random order. Chi-square analysis was used to determine whether statistically significant differences in success rates were found between biometers. Within-subject standard deviation (Sw), test-retest repeatability (TRT), coefficient of variation (CoV), and intraclass correlation coefficients (ICCs) were calculated to analyze the intraobserver repeatability. Bland-Altman plots were used for agreement assessment. RESULTS: Axial length measurements were successfully measured in 166 eyes (97.08%) with the IOLMaster 700, 166 eyes (97.08%) with the OA-2000, 170 eyes (99.42%) with the Argos, and 138 eyes (80.70%) with the IOLMaster v5.4. Chi-square analysis indicated a significant difference in the failure rate between PCI- and SS-OCT-based biometers (P < .001). Intraobserver repeatability for the IOLMaster 700, OA-2000, and Argos showed excellent repeatability with low TRT (0.03, 0.06, and 0.05 mm, respectively), low CoV (0.04%, 0.10%, 0.07%, respectively), and high ICC (1.000, 0.999, and 1.000, respectively). The Bland-Altman 95% limits of agreement were as narrow as 0.09 mm, indicating excellent agreement among the three SS-OCT biometers and the PCI biometer. CONCLUSIONS: The three SS-OCT biometers showed a significantly higher success rate for axial length measurement than the IOLMaster v5.4 in various lens opacities. These SS-OCT biometers are likely to become the gold standard for axial measurement. [J Refract Surg. 2019;35(2):115-120.].

Comparison of two biometers: A swept-source optical coherence tomography and an optical low-coherence reflectometry biometer.

PURPOSE: The technological improvements in optical biometers have made cataract surgery evolve to the level of refractive surgery. This study assessed the correlation and agreement between a biometer using swept-source optical coherence tomography technology (IOLMaster 700; Carl Zeiss Meditec, Jena, Germany) and a biometer using optical low-coherence reflectometry (Lenstar; Haag Streit, Koeniz, Switzerland). PROCEDURES: Optical biometric measurements were taken with the IOLMaster 700 and the Lenstar on 129 eyes of 129 patients referred for cataract surgery. We compared biometric data (axial length, mean keratometry, central pachymetry, anterior chamber depth, lens thickness, and horizontal white-to-white measurement) and the emmetropic intraocular lens power calculated with SRK/T and Haigis formulas. Correlation and agreement for these parameters were evaluated. RESULTS: Only anterior chamber depth measurements (3.05 ± 0.07 vs 3.07 ± 0.07, p < 0.001) and the white-to-white measurement (11.97 ± 0.07 vs 12.06 ± 0.07, p < 0.001) differed significantly between the machines. Correlations and agreements were excellent, with perfect agreement for axial length measurement (r = 1, intraclass correlation coefficient = 1). Emmetropic intraocular lens power did not differ between devices with SRK/T formula (20.94 ± 0.51 vs 20.92 ± 0.50, p = 0.51). With Haigis formula, there was a statistically significant difference (21.04 ± 0.52 vs 20.84 ± 0.52, p < 0.001). CONCLUSION: This study suggests that there is a very high correlation and agreement for the biometric measurements and calculation of intraocular lens implant power with the SRK/T formula.