No abstract available.
Biometry* ; Rheology* ; Umbilical Arteries*

PURPOSE: To compare and evaluate device efficacy using white-to-white (WTW) diameter measurements by IOLMaster(R), Lenstar(R), Orbscan II(R), and a manual method with anterior segment photographs in normal eyes. METHODS: Three sets of WTW diameter measurements were obtained from 62 normal eyes of 31 patients, using the Orbscan II(R), Lenstar(R), IOLMaster(R), and a manual method with anterior segment photographs. Repeatability of each device was evaluated by coefficient of variation. ANOVA and Pearson's correlation were used to compare the differences among the devices. Bland Altman plot was performed to assess measurement agreement among the devices. RESULTS: The mean WTW distance was 11.79 +/- 0.46 mm with Orbscan II(R), 12.05 +/- 0.38 mm with Lenstar(R), 12.15 +/- 0.36 mm with IOLMaster(R), and 12.30 +/- 0.40 mm with a manual method. There were significant differences in the results among the methods (ANOVA, p < 0.05). There were significant correlations between the devices except Orbscan II(R) (Pearson's correlation, r > 0.8, p < 0.05). The coefficient of variation of Orbscan II(R) was larger than those of Lenstar(R) and IOLMaster(R). CONCLUSIONS: The WTW measurement using Orbscan II(R) has low correlations with other devices and lower repeatability. Our findings suggest that partial coherence interferometry should be considered as a new standard.
Biometry ; Eye ; Humans ; Interferometry

This paper summarized the internal and external development of medical metrology, posed its main problem and studied its development trend.
Biometry ; Epidemiologic Measurements

OBJECTIVEThe Chinese Journal of Hepatology is a key journal in the research field of liver diseases in China. Ranked by the impact factor, which was issued and used by the Institute of Scientific and Technical Information of China, it is in fourth position among medical journals in China. In order to evaluate the journal, some facts about it were surveyed, including the number of pages, the number of papers in each issue, organizations of the authors, funding for their works, the impact factor, immediacy index, statuses of the articles' references, and a listing of their being cited.

METHODSThe number of pages of each issue, the number of papers in every volume, and citations were quantitatively analyzed. Funding, impact factor, immediacy index, citations and organizations of the authors were analyzed by weighted Rank Sum Ratio (RSRw).

RESULTSIn the five years, 1999, 2000, 2001, 2002, and 2003, (1) The Chinese authors came from 26 of the 31 provinces and cities in China. 48.8% in 1999 to 71.7% in 2003 of the authors were working in medical universities or medical colleges, and some authors were overseas experts. (2) The number of articles cited in the five years were 702, 1158, 1087, 1178 and 1744. (3) The number of papers published were 248, 221, 242, 212 and 336. (4) Impact factors of the journal were 0.897, 0.931, 1.421, 1.858, 1.440. With the cites, immediacy index, cited rate, ratios of research provided by national or international funds and number of organizations of authors evaluated, the RSRw results of the five years were 0.2750, 0.3417, 0.5000, 0.5000 and 0.5000.

CONCLUSIONThe Chinese Journal of Hepatology is well-known and is one of the highest academic quality medical journals in China. It reflects the progress of liver disease research in China.

PURPOSE: To compare axial length, anterior chamber depth, and keratometric measurements of an optical low-coherence reflectometry device with those of other ocular biometry devices and evaluate the accuracy of predicting postoperative refraction. METHODS: A total of 32 eyes in 32 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured by optical low-coherence reflectometry (Lenstar LS900(R)), partial coherence interferometry (IOL master(R)), and ultrasound. The SRK/T formula was used to calculate IOL power, and predictive error that subtracts predictive refraction from postoperative refraction was compared among ocular biometry devices. RESULTS: Axial length, anterior chamber depth, and keratometry had a strong correlation and demonstrated no statistically significant differences between Lenstar LS900(R) and other devices. The Bland-Altman plots showed a high degree of agreement between Lenstar LS900(R) and other devices. The mean absolute prediction errors in Lenstar LS900(R) and IOL master(R) were not significantly different. CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using Lenstar LS900(R) were as accurate as IOL master(R) and ultrasound.
Anterior Chamber ; Biometry ; Cataract ; Eye ; Humans ; Interferometry

PURPOSE: To investigate clinical availability of AL-Scan(TM) (Nidek, Gamagori, Japan) by comparing corneal refractive power with AL-Scan(TM), Autokeratometer(TM) (Topcon KR-1, Tokyo, Japan) and Pentacam(TM) (Oculus, Wetzlar, Germany) devices. METHODS: Seventy-one patients (142 eyes) who visited our hospital for refractive surgery were tested using AL-Scan(R), Autokeratometer and Pentacam(R) and corneal refractive power was compared among devices. RESULTS: When comparing measurements with AL-Scan(R), Autokeratometer and Pentacam(R), the mean corneal refractive power was 43.37 +/- 1.32 D (2.4 mm zone), 43.35 +/- 1.32 D (3.3 mm zone), 43.36 +/- 1.35 D, and 43.35 +/- 1.36 D respectively and showed no significant differences. Corneal refractive power had strongly positive linear correlation (p < 0.001) and Bland-Altman plots showed high degree of agreement among AL-Scan(R), Autokeratometer and Pentacam(R) devices. CONCLUSIONS: Because measuring ocular biometry with AL-Scan(R) including axial length, intraocular lens power calculation and topography simultaneously is possible, clinical use is convenient. Corneal refractive power was not different when compared with autokeratometer and Pentacam(R) devices, thus, AL-Scan(R) can be used in the clinical environment.
Biometry ; Humans ; Lenses, Intraocular ; Refractive Surgical Procedures

PURPOSE: To compare ocular biometry measured using 4 applanation ultrasonographic biometry devices and evaluate the accuracies of the refractive outcomes after cataract surgery. METHODS: A total of 60 eyes in 60 patients who received cataract surgery were included in the present study. The axial length was measured using applanation ultrasonographic biometry devices (Aviso(R), Hi-Scan(R), UD-6000(R), P37-II(R)). Additionally, keratometry was measured using an autokeratometer (Topcon KR 8000) and the SRK/T formula was used to calculate intraocular lens (IOL) power. Two months after cataract surgery, the refractive outcome was determined, and results from the 4 different applanation ultrasonographic biometry devices were compared. RESULTS: Axial lengths were 23.52 +/- 1.45 mm, 23.51 +/- 1.04 mm, 23.54 +/- 1.58 mm, and 23.52 +/- 1.38 mm measured using Aviso(R), Hi-Scan(R), UD-6000(R), and P37-II(R), respectively with no statistically significant differences observed (p = 0.92). The mean absolute error (MAE) of the Aviso(R), Hi-Scan(R), UD-6000(R), and P37-II(R) was 0.41 +/- 0.32 diopter (D), 0.40 +/- 0.30 D, 0.36 +/- 0.26 D, and 0.39 +/- 0.26 D, respectively. The mean numerical error (MNE) was 0.39 +/- 0.37 D, 0.36 +/- 0.32 D, 0.26 +/- 0.29 D, and 0.38 +/- 0.32 D, respectively. The differences between the 4 different applanation ultrasonographic biometry devices were not statistically significant (p = 0.90, p = 0.81). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using Aviso(R), Hi-Scan(R), UD-6000(R), P37-II(R) showed no significant differences.
Biometry* ; Cataract ; Humans ; Lenses, Intraocular ; Refractive Errors

PURPOSE: To evaluate the reproducibility and accuracy of axial length and anterior chamber depth measurements from IOL Master(R). METHODS: The axial length and anterior chamber depth measurements in 30 eyes with normal crystalline lens, 30 eyes with cataract and 30 pseudophakic eyes were measured by two practitioners using IOL Master(R) followed by A-scan and Orbscan II. The reproducibility of IOL Master(R) was analyzed by comparing the results from the first and second practitioners. To evaluate the accuracy of IOL Master(R), the axial length was compared to A-scan and the anterior chamber depth was compared to A-scan and Orbscan II. RESULTS: The difference between the axial length and anterior chamber depth measurements from the two practitioners using IOL Master(R) were not statistically significant (p>0.05). The axial length of measurement from IOL Master(R) was 0.16 mm, 0.18 mm, and 0.96 mm longer than that from A-scan, in the normal, cataract and pseudophakic groups, respectively. In addition, the anterior chamber depth measurement from IOL Master(R) was significantly deeper than that from A-scan and Orbscan II (p<0.05). CONCLUSIONS: There was good reproducibility and accuracy of axial length and anterior chamber depth measurements from IOL Master(R). However, some patients who had media opacity were not measured using IOL Master(R). It is a noncontact method, which provides an alternative to A-scan.
Anterior Chamber ; Biometry* ; Cataract ; Humans ; Lens, Crystalline

PURPOSE: To evaluate the reproducibility and repeatibility of biometry in cataractous eyes, pseudophakic eyes and eyes having undergone refractive surgery. The OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) instruments were compared, as were. The accuracies of the refractive results after cataract surgery. METHODS: The biometries of 45 cataractous eyes, 31 pseudophakic eyes, and 32 eyes having undergone refractive surgery were measured by two practitioners using OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) instruments. The paired t-test was used to compare the reproducibilities in the three groups. RESULTS: There were no differences in axial length among the groups when using any of the instruments. There was no significant difference in the repeatibility regardless of the instrument used, although. In the cataractous eyes, pseudophakic eyes and eyes with refractive surgery, OcuScan(R)RxP showed the highest repeatability. However, we knew that all three instruments were excellent in the repeatability because the difference was less than 1.5%. The Prediction error of the instruments with regard to refractive results could not be determined after cataract surgery. In some patients with severe cataract, measurement was impossible for both the LENSTAR(R) and IOL Master(R) instruments. CONCLUSIONS: In all groups, OcuScan(R)RxP, LENSTAR(R) and IOL Master(R) showed no significant differences with regard to reproducibility or prediction of refractive power after surgery. Among three groups, the repeatability was rather high in the existing ultrasound method than in the partial coherence interferometers. In some patients with severe cataract, measurement was impossible for both the LENSTAR(R) and IOL Master(R) instruments.
Biometry ; Cataract ; Eye ; Humans ; Refractive Surgical Procedures

PURPOSE: To investigate the accuracy of measuring ultrasonic axial lengths using A-scan (Ocuscan(R), Alcon, USA) on opaque intraocular lenses after hydrophilic lens (ACRL-160(R), Ophthalmed, USA) implantation. METHODS: We measured axial length through ultrasonic biometry prior to intraocular lens exchange. Twelve eyes of 14 patients who had intraocular lens opacity following hydrophilic acryl lens implantation were examined in a clinical study. We compared pre-cataract operative axial lengths to pre-IOL exchange axial lengths. The pre-IOL exchange axial lengths were measured in aphakic and pseudophakic modes. In the pseudophakic mode, the ultrasound velocity through an IOL was set at a rate ranging between 1,500 m/sec to 2,200 m/sec. RESULTS: The pre-IOL exchange axial lengths in the pseudophakic mode at the rate of 1,600 m/sec in lens velocity were the closest to pre-cataract operative values (p=0.88). CONCLUSIONS: When pre-cataract operative axial length is known with a hydrophilic acrylic intraocular lens, previous values may be used for IOL exchange of an opacity patient. If not, however, the closest values to pre-cataract operative axial lengths may be obtained by setting the velocity in the pseudophakic mode to a lens velocity rate of 1,600 m/sec.
Biometry ; Eye ; Humans ; Lenses, Intraocular ; Ultrasonics