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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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Background: One of the most widely performed surgical procedures nowadays is cataract surgery combined with monofocal intraocular lens implantation (IOL). Monofocal IOLs can compensate for the spherical refractive error but not astigmatism. Thus, patients with astigmatism are unable to see well after surgery without spectacles. A new generation of IOLs called toric IOLs, improve uncorrected visual acuity in eyes with high astigmatism due to a specific lens design. This study aimed to present a practical method of toric intraocular lens (IOL) implantation based on a refractive power analyzer system and slit-lamp observation.Material & Methods:This prospective study comprised 30 patients who underwent toric IOL implantation with cataract extraction at the Department of Ophthalmology, National Institute of Ophthalmology, Dhaka, Bangladesh. This study was conducted from Jan 2021 to Dec 2021. Approval from the local ethical committee was obtained.Results:The study included 45 eyes of 30 patients. The sex distribution of the study patients where the male was 18(60%) and the female was 12(40%). In the age distribution of the study, 5(16.67%) patients were from the 60-69 range, 10(33.33%) patients were from the 70-79 range, and 15(50.00%) patients were from the 80-89 range. The patients’ demographic variables consequently. Changes in visual acuity and refraction are shown in table-4 thorough preoperative and postoperative. Postoperative IOL alignment methods are shown in table-5, the mean±SD of the slit-lamp target was 2.55±2.76 and in the range, of 0.0 to 12.0, the mean±SD of the corneal analyzer target was 2.55±1.98 and range was 0.0 to 11.0, and the mean±SD of the slit-lamp corneal analyzer was 3.27±2.98 and range was 0.0 to 16.0.Conclusions:We studied 2 methods of assessing toric IOL alignment postoperatively and found no significant difference between them. Both were reliable and predictable. In addition, we found that the simple preoperative marking technique we used yielded toric IOL alignment that was as accurate as that obtained with other commonly used techniques and that was within a clinically acceptable level.
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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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Objective:To compare the accuracy of IOLMaster 700 and IOLMaster 500 in intraocular lens (IOL) power calculation.Methods:A cross-sectional study was conducted.Two hundred and sixty-two eyes of 262 patients who underwent phacoemulsification combined with IOL implantation at the Eye Hospital of Wenzhou Medical University from November 2018 to November 2019 were enrolled.Preoperative biometry for cataract surgery was performed using IOLMaster 700 and IOLMaster 500.IOL power was calculated through the built-in formulas, Haigis, Holladay Ⅰ, Hoffer Q and SRK/T of the two devices.The difference in IOL power calculation between the two devices was analyzed through the prediction error of IOL power calculation using different formulas across different axial length (AL) ranges.This study complied with the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Eye Hospital of Wenzhou Medical University (No.2020-038-K-33). Written informed consent was obtained from each patient before the surgery.Results:There was no significant difference in mean absolute error (MAE) between IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T over the entire AL range (all at P >0.05). The MAE of IOLMaster 500 was 0.47 (0.24, 0.90) D, which was significantly lower than 0.50 (0.28, 0.99) D of IOLMaster 700 using Holladay Ⅰ formula ( Z=-3.120, P=0.002). When AL was <22.0 mm and ≥24.5 mm-<26.0 mm, there was no significant difference in MAE between the two devices using the four formulas (all at P >0.05). When AL was ≥22.0 mm-24.5 mm, there was no significant difference in the MAE between the two devices using Haigis, Hoffer Q and SRK/T (all at P >0.05), but 0.42 (0.18, 0.75) D from IOLMaster 500 was smaller than 0.45 (0.25, 0.79) D from IOLMaster 700 using Holladay Ⅰ, showing a statistically significant difference ( Z=-3.487, P <0.001). But the difference was negligible and therefore was of no clinical significance.When AL was ≥26.0 mm, there was no statistically significant difference in the MAE between the two devices using Haigis, Holladay Ⅰ and SRK/T, but 0.66 (0.38, 1.00) D from IOLMaster 500 was significantly smaller than 0.98 (0.62, 1.32) D from IOLMaster 700 using Hoffer Q ( Z=-3.046, P=0.002). Conclusions:The refractive prediction accuracy of IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T is similar over the entire AL range.For patient with long AL, the IOL calculation from IOLMaster 700 using Hoffer Q is significantly larger than that from IOLMaster 500, which requires extra caution in clinical practice.The accuracy of IOLMaster 700 and IOLMaster 500 for IOL prediction is very similar.
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@#AIM: To compare the change of refractive power and corneal high-order aberrations after femtosecond laser-assisted excimer laser <i>in situ</i> keratomileusis(FS-LASIK)and FS-LASIK combined with accelerated corneal cross-linking(FS-LASIK Xtra)for high myopia correction, and to evaluate the early effects of two surgical methods to correct high myopia. <p>METHODS:Retrospective case-control study. Totally 42 patients(84 eyes)with high myopia underwent FS-LASIK Xtra and FS-LASIK in our hospital from April 2019 to April 2020 were followed up for 3mo, including 21 patients in each group(42 eyes). The uncorrected visual acuity(UCVA), spherical equivalent(SE), astigmatism and corneal high-order aberration of the two groups were analyzed and compared.<p>RESULTS: The UCVA of the FS-LASIK Xtra group was significantly lower than that of the FS-LASIK group at 1d after surgery(<i>P</i><0.01), there was no statistical difference in UCVA at the other time points after surgery between the two groups(<i>P</i>>0.05). The postoperative SE of the two groups was significantly lower than that before surgery, at 3mo after surgery, 38 eyes(90%)in the FS-LASIK Xtra group and 41 eyes(98%)in the FS-LASIK group had SE within ±1.00D. In both groups, 35 eyes(83%)had residual astigmatism within 0.50D after surgery. The total corneal high-order aberrations, spherical aberrations, coma and clover aberrations in the two groups were increased at 3mo after surgery, the total high-order aberration and clover aberration in the FS-LASIK Xtra group were greater than those in the FS-LASIK group(all <i>P</i><0.05).<p>CONCLUSION:FS-LASIK and FS-LASIK Xtra have good effectiveness and predictability in correcting high myopia in the early postoperative period, the total high-order aberrations of the cornea both increased in the early postoperative period, and the patients who underwent FS-LASIK Xtra were increased significantly.
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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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Objective To compare the differences of corneal biomechanics in different types of glaucoma and its related influence factors,and to investigate the change trends of cornea biomechanics after the operations.Methods In a prospective comparative case series,61 eyes of 61 acute primary angle-closure glaucoma (APACG)(remission or chronic phase)patients,94 eyes of 94 chronic primary angle-closure glaucoma (CPACG) patients,70 eyes of 70 primary open angle glaucoma (POAG) patients and 64 eyes of 64 age-related cataract (ARC) patients were recruited in Tianjin Eye Hospital from January to July,2017.Corneal biomechanical properties were measured by using Corvis ST.The differences of corneal biomechanics in different types of glaucoma and the change trends after surgeries were assessed;the association between parameters and the age,intraocular pressure after correction (IOPcc),central cornea thickness (CCT),axial length (AL),average corneal diopter (K) were assessed by multiple linear regression analysis.This study followed the Declaration of Helsinki.This study protocol was approved by Ethic Committee of Tianjin Eye Hospital (TJYYLL-2016-17).Written informed consent was obtained from each subject prior to any medical examination.Results Compared with the ARC group,the first applanation velocity (A1V)and second applanation time (A2T) were both smaller in preoperative CPACG,POAG groups (all at P＜0.05);compared with the ARC group and APACG group,second applanation velocity (A2V) was larger in preoperative CPACG,POAG groups,the differences were all statistically significant (all at P＜0.05).A1V,A2T,deformation amplitude (DA) and peak distance (PD) were negatively correlated with IOPcc (r =-0.494,-0.612,-0.652,-0.277;all at P＜0.05),A2V,first applanation time (A1T) and central curvature radius (CCR) were positively correlated with IOPcc (r =0.508,0.960,0.249;all at P ＜ 0.05);first applanation length (A1 L) and second applanation length (A2L) were negatively correlated with K (r =-0.323,-0.227;both at P＜0.05);A 1 V,A2T and DA were positively correlated with K (r =0.214,0.256,0.242;all at P＜0.05).Compared with preoperative,the A1T and A2V were reduced,A1V,A2T and DA were increased in one month after surgery in CPACG group;the A1T and A2V were reduced,the A2T and DA were increased in one month after surgery in POAG group,and the differences were all statistically significant (all at P＜0.05).Compared with preoperative,there were no statistically significant differences between the parameters in one month after surgery in APACG group and ARC group (all at P ＞0.05).Conclusions CPACG and POAG have poorer ability of corneal deformation,which gradually returns to normal after surgery;because the intraocular pressure of APACG (remission or chronic stage) return to normal after transient elevated stage,the corneal biomechanics is basically similar to ARC,which has no difference between pre-and pos-operation.The parameters of corneal biomechanics are affected by IOPcc and K.
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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.
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Humans , Anterior Chamber , Loa , OutpatientsABSTRACT
Objective To investigate the effects of congenital ptosis on refractive power of the corneal surface.Methods Forty-five patients (90 eyes) with congenital ptosis in the First Affiliated Hospital of Kunming Medical University were examined from October 2013 to June 2015.Corneal topographic analysis was performed in both the ptosis and the normal eyes.The comparison between the ptotic eye and the normal eye was done according to the topographic results.Results Among 90 eyes,55 were ptotic and 35 were normal.Amblyopia was detected in 21 ptotic eyes (38.2％).No correlation was found between amblyopia and the severity of ptosis (x 2=2.617,P＞0.05).Ptotic eye showed an asymmetrical bow tie pattern (23 eyes) and an irregular pattern (32 eyes) on corneal photography and the maximum refractive power occurred at the inferior quadrant of the corneal horizontal axis.Difference value of the average refractive power of the cornea between lower side and upper side in ptotic eyes was higher than that of the normal eyes at 5mm and 7mm diameter areas (P＜0.01) except for 3mm diameter area (P＞ 0.05).Conclusion Congenital ptosis may lead to the change of refractive power of the local corneal surface.Amblyopia has no correlation with the severity of ptosis.
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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
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 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 measure choroidal thickness in healthy myopic eyes and to evaluate the relationship among choroidal thickness and refractive power and axial length. METHODS: Eighty healthy myopic eyes were evaluated in the present study. The refractive power was measured using an automatic refractor and the axial length using A-scan. The subjects were divided into two groups based on refractive power (> or =-6.0 D and or =25 mm and <25 mm). The choroidal thickness was measured using spectral domain (SD) optical coherence tomography (3-dimensional [3D] OCT-2000, Software Version 6.01; Topcon Corp., Tokyo, Japan), and the statistical relationship between the two groups was analyzed. RESULTS: A statistically significant difference was found in choroidal thickness according to refractive power and axial length between the two groups (p < 0.001 and p < 0.05, respectively). CONCLUSIONS: Refractive power and axial length had a significant relation to choroidal thickness measured by OCT. When excluding eyes with pathologic myopia, high myopia in healthy eyes may cause choroidal thinning.
Subject(s)
Choroid , Eye , Myopia , Tokyo , Tomography, Optical CoherenceABSTRACT
Background The measurement of the extraocular muscle is critical for the diagnosis of extraocular muscle diseases,but conventional medical imaging techniques present some shortcomings because of the contact pattern.The anterior segment optical coherence tomography (OCT) is thought to be an in vivo noninvasive optical diagnostic imaging method.Objective This clinical study attempted to seek an available approach to the evaluation of the anatomic structure of human horizontal rectus insertion with Visante OCT.Methods One hundred and fourteen eyes of 58 subjects were included in this study and were divided into the low refractive power group (≤-3.00 D) with 43 eyes,moderate refractive power group(＞-3.00 D-≤-6.00 D) with 49 eyes and high refractive power group(＞-6.00 D) with 22 eyes.The horizontal rectus insertion distance to the scleral spur and its thickness were measured by Visante OCT.The correlation of the refractive power with the rectus insertion distance or thickness was analyzed.Written informed consent was obtained from each subject before medial assessment.Results The average distance from the scleral spur to the lateral and medial rectus insertion were (5.23±0.50)mm and (3.81±0.46)mm respectively.The average thickness of the lateral and medial rectus insertions were (0.39±0.06)mm and (0.39±0.06)mm respectively,showing no significant differences in comparison with those of ultrasound biomicroscopy (P=0.338,P=0.759).The lateral and medial rectus insertion distances were (5.25±0.45)mm and (3.74±0.53)mm in the low refractive power the group,(5.22±0.60)mm and (3.81±0.42)mm in the moderate group and (5.20±0.35)mm and (3.90±0.42)mm in the high refractive power group,presenting inconsiderable difference among these three groups(lateral rectus: χ2=0.054,P=0.974;medial rectus: F=0.508,P=0.604).The thickness of the lateral and medial rectus insertions were (0.41±0.06)mm and (0.40±0.06)mm in the low refractive power group,(0.40±0.07)mm and (0.37±0.07)mm in the moderate refractive power group,(0.36±0.05)mm and (0.39±0.05)mm in the high refractive power group with a significant difference among lateral rectus (F=4.922,P=0.009) but not medial rectus (F=2.152,P=0.125).The lateral rectus insertions thickness in the high refractive power group was thinner than that in low refractive power group (P＜0.05).A positive correlation was found between refractive power and the thickness of lateral or medial rectus insertions (r=0.284,P＜0.01).Conclusion Visante OCT is a uscful way in measuring the distance and thickness of the extraocular muscles.Lateral rectus insertions thickness tends to be thinner with the worsening of myopia,which is obvious in high myopia.
ABSTRACT
PURPOSE: To investigate changes in corneal astigmatism and refractive power in intermittent exotropia after lateral rectus recession with or without medial rectus resection. METHODS: We compared visual acuity, spherical equivalent, refractive power, astigmatism from cycloplegic refraction, and Orbscan corneal topography in two groups consisting of 40 eyes from 20 patients who underwent bilateral lateral rectus recession (Group 1) and 33 eyes from 33 patients who underwent monocular medial rectus resection with lateral rectus recession (Group 2) immediately preoperatively and at 1 and 4 weeks postoperatively. RESULTS: In Group 1, the refractive power changed +0.12 D on average in the horizontal median and -0.08 D on average in the vertical median at 1 week postoperatively. The refractive power changed +0.07 D on average in the horizontal median and -0.04 D on average in the vertical median at 4 weeks postoperatively. No significant change in the corneal astigmatic axis was detected. In Group 2, the refractive power changed +0.4 D on average in the horizontal median and -0.19D on average in the vertical median, and the corneal astigmatic axis significantly shifted by +0.51 D in the 'with-the-rule astigmatism' direction at 1 week postoperatively (p=0.02). However, the refractive power changed +0.2 D on average in the horizontal median and -0.09 D on average in the vertical median, and the corneal astigmatic axis changed +0.2 D at 4 weeks postoperatively, although these values were not statistically significant. CONCLUSIONS: Postoperative refractive power and corneal astigmatism did not change significantly, as compared to preoperative values, at 4 weeks postoperatively in the lateral rectus recession-only or medial-and-lateral rectus recession group.