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AIM:To evaluate the agreement of corneal high-order aberrations from Topcon KR-1W, i.Profiler and OPD-Scan Ⅲ wavefront aberrometers in myopic adults.METHODS:A prospective clinical study. A total of 92 adult patients(92 eyes)with myopia in the department of optometry, the People's Hospital of Guangxi Zhuang Autonomous Region from June to August 2022 were enrolled. The third-order and fourth-order corneal aberrations at the pupil diameter of 4 and 6mm were measured by Topcon KR-1W, i.Profiler, and OPD-Scan Ⅲ, respectively. The difference and agreement of the three aberrometers were evaluated.RESULTS: The measurements at 6mm pupil diameter were all greater than those at 4mm pupil diameter. Although there were no statistical differences in the measurements of Z-44、Z-24 by the three aberrometers at 4 pupil diameter(P>0.05), there were statistical differences in other measurements(P<0.05). The aberration results measured by the three aberrometers were statistically different at the 6mm pupil diameter(P<0.05). The 95% limit of agreement(95%LoA)of the measurements of higher-order aberration, including the third-order aberrations at 4mm pupil diameter and the third-order and fourth-order aberrations at 6mm pupil diameter(except for the Z-24)were greater than 0.1μm. The concordance correlation coefficient(Pc)was lower than 0.90, indicating a poor consistency. The correlation coefficients of corneal higher-order aberrations were significantly different among the three aberrometers at 4 and 6mm pupil diameter(r4mm=0.215～0.805, P4mm<0.05; r6mm=0.561～0.916, P6mm<0.001).CONCLUSION:There were significant differences in the measurements of the third- and fourth-order corneal aberrations at 4 and 6mm pupil diameter among Topcon KR-1W, i.Profiler, and OPD-Scan Ⅲ, and the agreements were poor, so they are not interchangeably in clinical applications.
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?AIM: To assess the consistency of refractive errors measured by two autorefractors in myopia screening of school-age Chinese children.?METHODS: Topcon RM- 8900 and Tianle RM - 9000 autorefractors were utilized to measure refractive errors under noncycloplegic condition in students aged 6 to 16 years old who were cluster sampled from four primary and secondary schools in Dongli district, Tianjin. Sperman correlation analysis and Bland-Altman method were used to evaluate the consistency of spherical diopters, cylindrical diopters and spherical equivalents measured by the two methods, and the axial difference distribution of astigmatism measured by the two methods was analyzed.?RESULTS:A total of 2276 eyes of 1138 subjects with a mean age of 10.49± 2.66 a were finally enrolled. Spearman correlation analysis showed that sphere ( r = 0.958, P<0.0001) , cylinder ( r= 0.769, P<0.0001 ) , and spherical equivalent ( r=0.962, P<0.0001) measured by Tianle RM-9000 were highly correlated with those measured by Topcon RM-8900, respectively. Bland-Altman analysis showed spherical diopters measured by Tianle RM-9000 were significantly more hyperopic ( P< 0.0001 ) with a mean difference of 0. 44 D ( SD: 0.37;95％ CI: -0.27, 1.16) while the maximum absolute value ( 1.13 D) of the difference within the 95％ CI was above the clinically acceptable range;however, no significant difference ( P=0.83) was found between cylindrical diopters measured by the two methods with a mean difference of -0.01 D ( SD: 0.31;95％ CI= -0.62, 0.61 ) while the maximum absolute value ( 0.62 D ) of the difference within the 95％CI was clinically acceptable. The proportion of the axial deviation within ± 20° was 84.6％( 1503/1777) in eyes with cylinder ≤-0.25D while that rose to 96.4％ ( 853/885) in eyes with cylinder ≤-0.75D.?CONCLUSION: Spherical diopters measured by Tianle RM-9000 have a significant hyperopia bias than those measured by Topcon RM-8900 while the consistency of cylindrical diopters and cylindrical axes is clinically acceptable.
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@#AIM: To assess the consistency of refractive errors measured by two autorefractors in myopia screening of school-age Chinese children.<p>METHODS: Topcon RM-8900 and Tianle RM-9000 autorefractors were utilized to measure refractive errors under noncycloplegic condition in students aged 6 to 16 years old who were cluster sampled from four primary and secondary schools in Dongli district, Tianjin. Sperman correlation analysis and Bland-Altman method were used to evaluate the consistency of spherical diopters, cylindrical diopters and spherical equivalents measured by the two methods, and the axial difference distribution of astigmatism measured by the two methods was analyzed.<p>RESULTS:A total of 2 276 eyes of 1 138 subjects with a mean age of 10.49±2.66 a were finally enrolled. Spearman correlation analysis showed that sphere(<i>r</i>=0.958, <i>P</i><0.0001), cylinder(<i>r</i>=0.769, <i>P</i><0.0001), and spherical equivalent(<i>r</i>=0.962, <i>P</i><0.0001)measured by Tianle RM-9000 were highly correlated with those measured by Topcon RM-8900, respectively. Bland-Altman analysis showed spherical diopters measured by Tianle RM-9000 were significantly more hyperopic(<i>P</i><0.0001)with a mean difference of 0.44 D(SD: 0.37; 95% <i>CI</i>: -0.27, 1.16)while the maximum absolute value(1.13 D)of the difference within the 95% <i>CI</i> was above the clinically acceptable range; however, no significant difference(<i>P</i>=0.83)was found between cylindrical diopters measured by the two methods with a mean difference of -0.01 D(SD: 0.31; 95% <i>CI</i>=-0.62, 0.61)while the maximum absolute value(0.62 D)of the difference within the 95% <i>CI</i> was clinically acceptable. The proportion of the axial deviation within ±20° was 84.6%(1 503/1 777)in eyes with cylinder ≤-0.25D while that rose to 96.4%(853/885)in eyes with cylinder ≤-0.75D. <p>CONCLUSION: Spherical diopters measured by Tianle RM-9000 have a significant hyperopia bias than those measured by Topcon RM-8900 while the consistency of cylindrical diopters and cylindrical axes is clinically acceptable.
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PURPOSE: To evaluate the corneal thickness values before and after refractive keratoplasty with the Topcon SP-2000 noncontact specular microscope(Topcon American Corp.) and the common standard ultrasonic pachymeter. METHODS: Corneal thickness was measured in 40 eyes of 20 patients, 5 times each before and after keratoplasty, with the Topcon SP-2000P and an ultrasonic pachymeter (DGH 1000, DGH Technology Inc.). The main outcome measures were accuracy and reproducibility as assessed with coefficient of variation (CV) of corneal thickness measurements. RESULTS: The reproducibility of corneal thickness measurements was better with the ultrasonic pachymeter (CV 0.36%) than with the Topcon SP-2000 (CV 1.23%). Mean corneal thickness measured by the Topcon SP-2000P before and after keratoplasty was significantly less than the mean values obtained with the ultrasonic pachymeter (14.4 micro meter; P<.0001, 5.6 micro meter; P<.01; respectively). Compared with theoretical ablated corneal thickness, ablated corneal thickness measured with the Topcon SP-2000P was significantly less (P<.01) than values obtained with the ultrasonic pachymeter (P=0.07) CONCLUSIONS: The noncontact Topcon specular microscope provides measurements of corneal thickness that are significantly less than those of the ultrasonic pachymeter, both before and after keratoplasty. These results indicate that these 2 techniques are not clinically comparable, thereby precluding interchangeable use of their data in planning or assessing keratoplasty.
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Humans , Corneal Pachymetry , Corneal Transplantation , Outcome Assessment, Health Care , UltrasonicsABSTRACT
The authors' clinical experience has suggested that the noncontact tonometer (NCT) has a tendency to record a lower intraocular pressure(IOP) than the Goldmann applanation tonometer(GAT) after excimer laser photo refractive keratectomy(PRK). This study was done to verify this tendency. We performed PRK on 177 eyes of 122 patients using a VISX 20/20 excimer laser, and topical fluorometholone was used after PRK. The eyes were divided into three groups according to their ablation depths, and the IOP was measured with the GAT and the Topcon NCT before surgery and 1, 3, 6, 9, and 12 months postoperatively. The mean postoperative IOP measured with the GAT or the NCT decreased as compared with the mean preoperative IOP(GAT: 1.67 ~ 2.90 mmHg, NCT:5.27 ~ 6.54 mmHg). The mean NCT reading was 1.12 mmHg higher than the mean GAT reading preoperatively, but was 2.48 ~ 2.88 mmHg lower than the mean GAT reading postoperatively. Difference between GAT and NCT measurements postoperatively was more prominent in the group of deeper ablation. These results suggest that we should be cautious of evaluating the IOP measured with the GAT or the NCT after PRK.