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Purpose: To evaluate a method using measured values of total corneal refractive power (TCRP) for a manufacturer’s online calculator by comparing it with the Barrett toric calculator (BTC) and Kane toric calculator (KTC) combined with simulated keratometry values (SimK). Methods: This was a retrospective case series. Patient records were reviewed to identify the patients who had biometry with the IOL Master 700 and Pentacam recorded before toric IOL implantation and refractive follow?up data after implantation. The predicted error in residual astigmatism was calculated by vector analysis according to the calculation methods and the measurements used. Results: A total of 70 eyes of 56 patients were included. The mean absolute astigmatism prediction errors were 0.6 ± 0.32, 0.59 ± 0.35, and 0.61 ± 0.35 D for the ATCTCRP, BTCSimK, and KTCSimK calculators, respectively (P = 0.934), and the centroid of the prediction errors were 0.3 D @ 178°, 0.11 D @ 102°, and 0.09 D @ 147°, respectively (P = 0.23). In the with?the?rule subgroup, the centroid of the prediction error was 0.34 D @ 176° for ATCTCRP and was the highest among the three calculation methods (P = 0.046). Conclusion: The ATCTCRP, BTCSimK, and KTCSimK calculators had similar performance with regards to their astigmatism prediction accuracy. The ATCTCRP calculator combined with 4.0?mm apex/ ring readings of TCRP was slightly intended to result in against?the?rule residual astigmatism.
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AIM: To compare the difference and consistency of corneal refractive power and astigmatism measured by CASIA2 and IOL Master 700 in patients with age-related cataract.METHODS: Retrospective study. A total of 153 patients(232 eyes)with age-related cataract admitted to Daping hospital from November to December 2021 were selected. The flat keratometry(Kf), steep keratometry(Ks), mean keratometry(Km), degree and axis of astigmatism(vector representation J0 and J45)of the anterior, posterior surfaces together with the total cornea from cataract patients were measured by CASIA2 and IOL Master 700, respectively. The difference, correlation and consistency of the two instruments were analyzed.RESULTS:There was no significant difference in J45 values of posterior corneal surface measured by CASIA2 and IOL Master 700(-0.006±0.038D vs. -0.005±0.044D, P>0.05), but there were significant differences in other parameters(all P<0.05). All parameters measured by the two instruments were significantly positive correlated(all r/rs>0.7, P<0.001); Bland-Altman analysis showed that the refractive power and astigmatism of the anterior cornea surface measured by the two facilities were in good consistency, while the refractive power of the posterior surface and the whole cornea showed poor consistency.CONCLUSION: CASIA2 and IOL Master 700 showed little differences and good consistency in the refractive power and astigmatism of the anterior, posterior and total corneal surface in cataract patients, which seems interchangeable. However, the refractive power of the posterior surface and the whole cornea has significant differences and poor consistency, which should not be interchange casually.
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Objective:To compare the difference and consistency of anterior corneal surface and total corneal refractive power and astigmatism measured by CASIA2, IOLMaster 700 and Pentacam in patients with age-related cataract.Methods:A diagnostic test was conducted.Two-hundred patients (200 eyes) with age-related cataract were enrolled in Tianjin Medical University Eye Hospital from March to April 2021.The steep keratometry (Ks), flat keratometry (Kf), mean keratometry (Km), degree and axis of astigmatism of the anterior and the total corneal surface of patients were measured by CASIA2, IOLMaster 700 and Pentacam, respectively.The astigmatism was transformed into J0 and J45 by Fourier transform formula.The differences and correlation of the measurements obtained with the three instruments were analyzed by one-way repeated measures analysis of variance and Pearson correlation analysis.The consistency was evaluated by Bland-Altman test.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (No.2021KY-07).Results:There were statistically significant differences in anterior corneal surface Kf and J0 measured by the three instruments ( F=18.563, 16.172; both at P=0.001). The Kf measured by CASIA2 was significantly higher than that measured by IOLMaster 700, and the J0 measured by IOLMaster 700 was significantly higher than that measured by Pentacam (both at P<0.05). There were statistically significant differences in total corneal Ks, Kf, Km and J0 measured by the three instruments, which from IOLMaster 700 were the largest, followed by CASIA2, then Pentacam ( F=1 300.447, 1 274.117, 1 609.713, 10.372; all at P=0.001). Pearson correlation analysis showed that the corneal refractive power measured by the three instruments was highly correlated (all at r>0.935, P<0.01), and the correlation of astigmatism values was weaker than the corneal refractive power ( r=0.623-0.908, all at P<0.01). Bland-Altman analysis showed that the three instruments had good consistency in measuring the anterior corneal surface refractive power, anterior corneal surface astigmatism and total corneal astigmatism, which were clinically acceptable, while the consistency of total corneal refractive power measurement was poor.The difference in measuring total corneal refractive power was large between IOLMaster 700 and Pentacam, and relatively small between CASIA2 and Pentacam. Conclusions:The consistency of CASIA2, IOLMaster 700 and Pentacam is good in measuring the anterior corneal surface refractive power of patients with age-related cataract, which can be substitutable, but poor in measuring the total corneal refractive power.The total corneal refractive power measurement from IOLMaster700 is the largest, the smallest from Pentacam, which is not recommended to be clinically exchangeable.
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AIM: To compare the distribution characteristics of axial sagittal front power(ASF), true net power(TNP), total corneal refractive power(TCRP)and the difference in back-front corneal radius ratio(B/F ratio)after cataract surgery.METHODS: A prospective study. A total of 156 patients(156 eyes)with age-related cataract who attend Weifang Eye Hospital for cataract surgery from December 2020 to May 2021 were collected. Pentacam was performed before operation and 3mo after operation to collect ASF, TNP and TCRP on 2, 4 and 6mm diameters rings and areas on the corneal apex and pupil-centered, as well as B/F ratio.RESULTS: 3mo after operation, there was no statistical difference in ASF on the 2mm diameters ring and area centered on the corneal apex compared with preoperative values(all P>0.05), however, the ASF values on the 4 and 6mm diameters rings and areas were significantly different from those before surgery(all P<0.05); There was no statistical difference in ASF on the 2mm diameters rings and areas centered on the pupil compared with preoperative values(all P>0.05). The postoperative values of TNP and TCRP on the 2, 4 and 6mm diameters rings and areas centered on the corneal apex and centered on the pupil were statistically different before surgery(all P<0.05). Preoperative, TCRP values were different between 2mm and 6mm and between 4mm and 6mm on both corneal apex and pupil-centered rings(all P<0.0167), TCRP values were all different between 2mm and 6mm diameters areas on corneal apex and pupil-centered(all P<0.0167); 3mo after operation, TCRP values were different on corneal apex and pupil-centered rings between 2mm and 6mm and between 4mm and 6mm diameters(all P<0.0167). While TCRP values on the corneal apex and pupil-centered areas were only different between 2mm and 6mm diameters(all P<0.0167). The preoperative B/F ratio of patients was 81.79%±1.87%, and the postoperative B/ F ratio of patients was 80.68%±2.23%(P<0.001).CONCLUSION: Corneal parameters of different diameters of rings and areas centered on the corneal apex and pupil before and after cataract surgery may change and differ, which should be taken into account when selecting the K value for intraocular lens calculation and individualizing the selection of IOLs based on corneal characteristics.
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@#AIM: To observe the changes of the development of the anterior segment in children after the treatment of laser photocoagulation(LP)for retinopathy of prematurity(ROP)by corneal topographic. <p>METHODS: In this retrospective case study, 25 children(50 eyes)as ROP group and 23 children(46 eyes)born at term as control group had participated in the study. The best corrected visual acuity(BCVA)was examined in both groups, and converted to LogMAR vision when statistical analysis was performed. The observation indicators of the Sirius anterior segment analysis system in the study were as follows: the horizontal iris diameter(HVID), corneal radius of the thinnest point, the thinnest point of the cornea, the maximum curvature of the cornea, the maximum radius of cornea curvature, central corneal thickness(CCT), corneal volume(CV), anterior chamber depth(ACD), anterior chamber volume and the anterior chamber angle.<p>RESULTS: The HVID, the thinnest point of the cornea, ACD, and the anterior chamber volume in ROP group were smaller than that in the control group(all <i>P</i><0.05). The CV and the anterior chamber angle in ROP group were smaller than that in the control group, but there was no significant difference between the two groups(all <i>P</i>>0.05). The BCVA was significantly better in the control group than that in the ROP group(0.07±0.10 <i>vs</i> 0.24±0.25, <i>P</i><0.05). <p>CONCLUSION: The development of eye anterior ganglion tissues of the ROP group had changed with steeper cornea, shallower anterior chamber, smaller angle of the anterior chamber and poor BCVA. All of the changes above might make it easier for the development of refractive errors and glaucoma.
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PURPOSE: To assess the degree of agreement of two rotating Scheimpflug cameras, Galilei G6 and Pentacam HR, in measuring corneal refractive power (K), anterior chamber depth (ACD), and central corneal thickness (CCT). METHODS: Measurement agreement was assessed in 40 eyes of 40 outpatients at our hospital. Measurements of anterior and posterior corneal refractive power (K), ACD, and CCT were compared between the Galilei G6 and Pentacam HR. RESULTS: For Galilei G6 (4 mm), Pentacam HR (3 mm) and Pentacam HR (4 mm), the anterior corneal refractive powers (K) were 44.35 ± 1.38 D, 44.09 ± 1.32 D, and 44.12 ± 1.35 D, respectively, and the posterior corneal refractive powers (K) were 6.39 ± 0.23 D, 6.45 ± 0.23 D, 6.45 ± 0.22 D. The differences in the results were statistically significant. The average ACD measurements using Galilei G6 and Pentacam HR were 3.26 ± 0.42 mm and 3.17 ± 0.42 mm, respectively, and the average CCT measurements were 556.65 ± 30.12 µm and 553.78 ± 29.42 µm. The differences in the measurements were statistically significant. In addition, ACD 95% limits of agreement (LoA) between Galilei G6 and Pentacam HR were in the range of -0.14~0.32 mm, and CCT 95% LoA were in the range of -12.54~18.29 µm. CONCLUSIONS: There were significant differences in measurements of anterior and posterior corneal refractive power (K), ACD, and CCT between the two cameras. Agreement analysis suggests that Galilei G6 and Pentacam HR should not be used interchangeably.
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Humans , Anterior Chamber , Loa , OutpatientsABSTRACT
PURPOSE: To assess the degree of agreement of two rotating Scheimpflug cameras, Galilei G6 and Pentacam HR, in measuring corneal refractive power (K), anterior chamber depth (ACD), and central corneal thickness (CCT). METHODS: Measurement agreement was assessed in 40 eyes of 40 outpatients at our hospital. Measurements of anterior and posterior corneal refractive power (K), ACD, and CCT were compared between the Galilei G6 and Pentacam HR. RESULTS: For Galilei G6 (4 mm), Pentacam HR (3 mm) and Pentacam HR (4 mm), the anterior corneal refractive powers (K) were 44.35 ± 1.38 D, 44.09 ± 1.32 D, and 44.12 ± 1.35 D, respectively, and the posterior corneal refractive powers (K) were 6.39 ± 0.23 D, 6.45 ± 0.23 D, 6.45 ± 0.22 D. The differences in the results were statistically significant. The average ACD measurements using Galilei G6 and Pentacam HR were 3.26 ± 0.42 mm and 3.17 ± 0.42 mm, respectively, and the average CCT measurements were 556.65 ± 30.12 µm and 553.78 ± 29.42 µm. The differences in the measurements were statistically significant. In addition, ACD 95% limits of agreement (LoA) between Galilei G6 and Pentacam HR were in the range of -0.14~0.32 mm, and CCT 95% LoA were in the range of -12.54~18.29 µm. CONCLUSIONS: There were significant differences in measurements of anterior and posterior corneal refractive power (K), ACD, and CCT between the two cameras. Agreement analysis suggests that Galilei G6 and Pentacam HR should not be used interchangeably.
Subject(s)
Humans , Anterior Chamber , Loa , OutpatientsABSTRACT
AIM: To evaluate the relationship between axial length ( AL ) , corneal and lens refractive power, and the refractive error in children. METHODS:Totally 44 children 88 eyes with refractive error who underwent retinoscopy with cycloplegia, to be measured spherical equivalent refractive error. Axial length was measured by a noncontact optical biometry ( ZEISS IOL-Master) , and corneal K and anterior chamber depth ( ACD) were also measured by the same machine. The refractive power of the lens was calculated by using the SRK formula. The patients were divided into 3 groups, myopia (SE+0. 50D) and emmetropia ( 0 to + 0. 50D ). Linear Correlation and Regression were used to evaluate the correlation among the optical parameters. RESULTS:Totally 44 subjects, 88 eyes, average 9. 04±2.39 years, spherical equivalent (SE) -3. 50D to +8. 75D. Hyperopic AL was shorter than the other two groups ( P CONCLUSION:As the children's growing up, SE trends to myopia, and AL becomes longer, and lens power is stronger.
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PURPOSE: To investigate the clinical availability of AL-Scan(R) (Nidek, GAMAGORI, Japan) by comparing anterior segment parameters measured with AL-Scan(R) and Pentacam(R) (Oculus, Wetzlar, Germany). METHODS: Seventy-three patients (117 eyes) who received refractive surgery at our hospital were tested with AL-Scan(R) and Pentacam(R). We compared measurements including anterior chamber depth, central corneal thickness, white-to-white, and corneal curvature. RESULTS: When comparing measurements obtained with AL-Scan(R) and Pentacam(R), the anterior chamber depth (p < 0.001), central corneal thickness (p < 0.001) and 2.4 mm zone K value (p = 0.038) showed significant differences; the white-to-white (p = 0.348) and 3.3 mm zone K value (p = 0.429) showed no significant differences. All AL-Scan(R) and Pentacam(R) parameters had a strong positive linear correlation (p < 0.001). The Bland-Altman plots showed a high degree of agreement between AL-Scan(R) and Pentacam(R) in all parameters except for anterior chamber depth. CONCLUSIONS: AL-Scan(R) is convenient to use clinically because simultaneous measurements of ocular biometry including axial length, intraocular lens power, and topography are possible. However, because differences in some anterior segment parameters exist when compared with Pentacam(R), measurements with AL-Scan(R) may require comparisons with other instruments.
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Humans , Anterior Chamber , Biometry , Lenses, Intraocular , Refractive Surgical ProceduresABSTRACT
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.
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Humans , Biometry , Lenses, Intraocular , Refractive Surgical ProceduresABSTRACT
PURPOSE: To report the evaluation and comparison of true corneal power after corneal refractive surgery through ARK, Orbscan II(R), Pentacam and IOL master. METHODS: Target IOL (Intraocular lens) power calculated with the SRK/T formula using SMK (Sungmo Eye Hospital keratometry), which is a new method for measuring corneal refractive power, was compared with the back-calculated ideal IOL power after cataract surgery for 30 eyes that required cataract surgery and had previously undergone refractive surgery. Target IOL powers calculated using 4 systems were compared with IOL power calculated using the clinical history method for 64 eyes that had undergone refractive surgery. RESULTS: Using SMK with the SRK/T formula, the actual refraction was within +/-0.5 diopter (D) of the intended refraction for 63.8% of eyes and within +/-1.0 D for 90.9% of eyes. Compared with target IOL power calculated with the clinical history method, target IOL power calculated by SMK with the SRK/T formula had a difference of 1.95 +/- 0.86 D, which was similar to the results calculated by the Haigis-L formula and by TNP with Haigis. CONCLUSIONS: The method of IOL calculation using SMK with the SRK/T formula showed the best predictability in patients after corneal refractive surgery. Comparatively accurate results were produced in IOL power calculations using the Haigis-L formula, and the TNP with Haigis method.
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Humans , Cataract , Refractive Surgical ProceduresABSTRACT
PURPOSE: To evaluate the accuracy of the chosen formula in short eyes and the effect of the anterior chamber depth (ACD) and corneal refractive power on the accuracy. METHODS: A total of 251 eyes out of 185 patients (axial length below 22.0 mm) who underwent cataract surgery in our hospital were retrospectively studied. Introcular lens (IOL) power was calculated with the Hoffer Q, SRK II, SRK-T and Holladay 1 formulas and refractive outcome was measured. Patients were divided into 2 groups based on ACD. The accuracy of the 4 formulas was compared and the errors according to the ACD were also evaluated. RESULTS: In eyes with short axial lengths, all formulas showed a tendency for hyperopic shifts. The Hoffer Q formula showed significantly high predictive accuracy. This tendency for hyperopic shifts was similar in the eyes with extremely short axial length, but a large refractive error deviation was observed. The 2 groups based on ACD showed no significant difference in the refractive error, but the group with deep ACD had a tendency for hyperopic shifts. The difference of the calculated IOL power between the 4 formulas was more pronounced in eyes with lower corneal refractive power. CONCLUSIONS: In eyes with short axial lengths, preoperative ACD and corneal refractive power had an influence on the accuracies of predicted IOL power. Therefore, these factors should be considered in IOL power determination.
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Humans , Anterior Chamber , Cataract , Refractive Errors , Retrospective StudiesABSTRACT
PURPOSE: To report a new method for measuring corneal refractive power after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) using the Orbscan(R) and autorefractokeratometer. METHODS: This study involved 12 cases that had undergone cataract surgery after corneal refractive surgery. Five cases had PRK and seven had LASIK. Keratometric values were evaluated with three different methods. The first, defined as RK, used an autorefractokeratometer (AK) (n=1.3375). The second, defined as K1, added the posterior surface diopter using AK and anterior surface diopter using an Orbscan. The last, defined as K2, added the posterior surface diopter and the anterior surface diopter using an Orbscan. Low K was a lower value between K1 and K2. RK, K1, K2 and Low K were compared with the back-calculated K value (Real K) 2 months after cataract surgery. RESULTS: The mean differences between RK, K1, K2, Low K and Real K were 3.08 +/- 0.98D, 0.41 +/- 0.66D, 0.27 +/- 0.77D, and -0.02 +/- 0.53D, respectively. In 9 of the 12 patients the difference was within 1D (75%) when either K1 or K2 was selected and in all patients, the difference between Low K and Real K was within 1D. CONCLUSIONS: The method of IOL calculation using Low K showed more accurate and predictable results in patients who had had cataract surgery after corneal refractive surgery.