AIM:To find a simple mathematical correlation between the lens base curve(BC) and keratometry findings(krf).METHODS:This retrospective study included 400 keratoconic eyes(350 patients) previously fit with rigid contac...AIM:To find a simple mathematical correlation between the lens base curve(BC) and keratometry findings(krf).METHODS:This retrospective study included 400 keratoconic eyes(350 patients) previously fit with rigid contact lenses at an academic eye center over a five year period.The patients were classified into five groups based on the keratometry findings(krf<7,krf:7-8,krf>8,krf-krs(difference between two keratometry;flat and steep)= 0.3-0.6,krf-krs >0.6mm as groups 1 to 5,respectively.Multivariate linear regression and Munro's correlation coefficient were employed to defer the formulas.RESULTS:A linear correlation could be found in all groups except for patients in group 3.For group 1,BC=0.211×krf+ 5.904.For group 2,BC=0.456×krf+4.160.For group 4,BC= 0.321×krf+5.219.For group 5,BC=0.337×krf+ 5.090.CONCLUSION:The development of new formulas for RGP fitting enables ophthalmologists to work with confidence and prevents unnecessary and frequent lens trials.The customary lens fitting methods are needed to be replaced by new formulas,which help to save time and costs.展开更多
AIM:To evaluate inter-device agreement of anterior keratometry obtained by the IOLMaster 500 and Pentacam HR in type 2 diabetic and non-diabetic patients.METHODS:Corneal measurements were sequentially performed in 60 ...AIM:To evaluate inter-device agreement of anterior keratometry obtained by the IOLMaster 500 and Pentacam HR in type 2 diabetic and non-diabetic patients.METHODS:Corneal measurements were sequentially performed in 60 diabetes mellitus(DM)and 48 age and sex-matched controls undergoing cataract surgery.Variables recorded included flat and steep keratometry,mean keratometry(Km),astigmatism magnitude,axis location,JO and J45 components.Bland-Altman plots and intraclass correlation coefficients were used for examination of agreement.Subgroup analyses were performed for astigmatism magnitude,diabetes duration,hemoglobin A1c(HbA1c)levels and diabetic retinopathy(DR)stage.RESULTS:Agreement for Km and astigmatism magnitude were considered good and moderate,with 95%limits of agreement(LoA)of-1.09 to 1.23 diopters(D)and-0.83 to 0.86 D in DM group,respectively;and-0.59 to 0.72 D and-0.98 to 0.75 D in non-DM group,respectively.In contrast,the 95%LoA for corneal axis exceeded the clinically relevant margins in both groups.In the total sample,only 41 eyes(38%)had a smaller than 5-degree difference.Diabetes duration,HbA1c levels and DR stage were not found to significantly affect agreement.Logistic regression showed that higher corneal power(P=0.021)and astigmatism magnitude(P=0.011)were associated with a decreased risk of having a difference in axis location greater than 10-degrees.CONCLUSION:In both groups,IOLMaster and Pentacam agree well for corneal power and moderately for astigmatism.However,axis location disagreement is frequent in eyes with flatter corneas and small amounts of astigmatism.展开更多
To evaluate the effect of preoperative keratometry on visual and refractive outcomes after Myopic LASER in Situ Keratomileusis (LASIK) in eyes with preoperative spherical equivalent (SE) of -6.00D or less. Material an...To evaluate the effect of preoperative keratometry on visual and refractive outcomes after Myopic LASER in Situ Keratomileusis (LASIK) in eyes with preoperative spherical equivalent (SE) of -6.00D or less. Material and Methods: A retrospective study enrolling clinical records of 482 eyes of 275 patients with myopia who underwent LASIK between 2009 and 2016. Subjects were grouped according to the degree of preoperative mean keratometry (Km), into three groups: Group 1 (Flat Cornea): Km ≤ 42.00 diopters (D);Group 2: 42.00 46.00D;Group 3 (Steep Cornea): Km ≥ 46.00D. To evaluate the prognostic impact of keratometry in Myopic LASIK, we considered the results measured at 6 months postoperatively, including uncorrected distance visual acuity (UDVA), postoperative sphere, cylinder, SE and its variation. Results: The mean preoperative SE was -3.91 ± 1.54D, ranging between -0.88 and -6.00D. The percentage of eyes achieving a postoperative SE of ±0.50D was 39.5%, 31.8% and 26% in groups 1, 2 and 3 respectively. Moreover, in group 3, 14.3% of the eyes had a residual SE of -2.00D or greater, contrasting with the groups 1 and 2 with only 6% - 7%. These results were found to be statistically significant. Concerning UDVA, eyes achieving 20/25 or more were 81.5%, 81.8% and 71.5%, and 20/50 or less were 6.7%, 6.2% and 11.7% in groups 1, 2 and 3 respectively. Conclusions: Myopic eyes with steeper corneas seem to have greater tendency to undercorrection, also presenting worse visual outcomes.展开更多
Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regio...Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children.Methods:Pachymetric and keratometric maps for both systems were evaluated.Central,midperipheral and peripheral corneal thickness(CT),keratometry and astigmatism power vectors were recorded.The three outcomes yielded by the same observer were used to assess intraobserver repeatability.The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility.Within-subject standard deviation,test-retest repeatability(TRT)and coefficient of variation(CoV)were used to analyze the intraobserver repeatability and interobserver reproducibility.Paired T-test and Bland-Altman were used to appraise interdevice agreement.Results:Seventy-eight eyes of 78 children were included.The CoV was≤2.12 and 1.10%,respectively,for repeatability and reproducibility.TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements.The SS-OCT device generated higher precision when acquiring CT data,whereas Scheimpflug system showed higher reliability when measuring corneal keratometry.Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device(P<0.001),the central and thinnest CT values were still of high agreement.The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas.Conclusions:The precision of CT measurements by SS-OCT was higher,while the reliability of keratometry measurements by the Scheimpflug system was higher in children.Apart from the measured values in the central corneal region,the thickness and keratometry readings should not be considered interchangeable between the two systems.展开更多
Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regio...Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children.Methods:Pachymetric and keratometric maps for both systems were evaluated.Central,midperipheral and peripheral corneal thickness(CT),keratometry and astigmatism power vectors were recorded.The three outcomes yielded by the same observer were used to assess intraobserver repeatability.The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility.Within-subject standard deviation,test-retest repeatability(TRT)and coefficient of variation(CoV)were used to analyze the intraobserver repeatability and interobserver reproducibility.Paired T-test and Bland-Altman were used to appraise interdevice agreement.Results:Seventy-eight eyes of 78 children were included.The CoV was≤2.12 and 1.10%,respectively,for repeatability and reproducibility.TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements.The SS-OCT device generated higher precision when acquiring CT data,whereas Scheimpflug system showed higher reliability when measuring corneal keratometry.Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device(P<0.001),the central and thinnest CT values were still of high agreement.The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas.Conclusions:The precision of CT measurements by SS-OCT was higher,while the reliability of keratometry measurements by the Scheimpflug system was higher in children.Apart from the measured values in the central corneal region,the thickness and keratometry readings should not be considered interchangeable between the two systems.展开更多
AIM:To analyze the differences,agreements,and correlation among total corneal power parameters generated by different instruments after myopic keratorefractive surgery.METHODS:The prospective cross-sectional study inc...AIM:To analyze the differences,agreements,and correlation among total corneal power parameters generated by different instruments after myopic keratorefractive surgery.METHODS:The prospective cross-sectional study included patients who underwent myopic keratorefractive surgery and received measurements of corneal power 3mo after surgery.Automated keratometer was used for the measurement of simulated keratometry(Sim K),sweptsource optical coherence tomography(SS-OCT)based biometer for total keratometry(TK),anterior segment-OCT for real keratometry(RK),and Scheimpflug keratometer for the true net power(TNP),the total corneal refractive power(TCRP)and equivalent K-readings(EKR).The differences among these parameters were analyzed,and the agreements and correlation between Sim K and other total corneal power parameters were investigated.RESULTS:A total of 70 eyes of 70 patients after myopic keratorefractive surgery were included.The evaluated corneal power parameters were as follows:Sim K 38.32±1.93 D,TK 37.54±2.12 D,RK 36.64±2.09 D,TNP 36.56±1.97 D,TCRP 36.70±2.01 D,and EKR 37.55±2.00 D.Pairwise comparison showed that there were significant differences(P<0.001)among all parameters except for between TK and EKR,RK and TNP,RK and TCRP(P=1.000,1.000,1.000,respectively).The limits of agreement between Sim K and TK,RK,TNP,TCPR,and EKR were 1.08,1.08,1.43,1.48,and 1.73 D,respectively.All parameters showed good correlation with Sim K,and the correlation coefficients were 0.995,0.994,0.983,0.982,and 0.975.CONCLUSION:Among the corneal power parameters after myopic keratorefractive surgery,the value of Sim K is the largest,followed by TK and EKR,with TCRP,RK,and TNP being the smallest.The differences among the parameters may be attributable to the different calculation principles.Correct understanding and evaluation of corneal power parameters can provide a theoretical basis for taking advantage of the total corneal power to improve the accuracy of intraocular lens calculation after keratorefractive surgery.展开更多
Background:The accuracy of using total keratometry(TK)value in recent IOL power calculation formulas in highly myopic eyes remained unknown.Methods:Highly myopic patients who underwent uneventful cataract surgery were...Background:The accuracy of using total keratometry(TK)value in recent IOL power calculation formulas in highly myopic eyes remained unknown.Methods:Highly myopic patients who underwent uneventful cataract surgery were prospectively enrolled in this prospective comparative study.At one month postoperatively,standard deviation(SD)of the prediction errors(PEs),mean and median absolute error(MedAE)of 103 highly myopic eyes were back-calculated and compared among ten formulas,including XGboost,RBF 3.0,Kane,Barrett Universal II,Emmetropia Verifying Optical 2.0,Cooke K6,Haigis,SRK/T,and Wang-Koch modifications of Haigis and SRK/T formulas,using either TK or standard keratometry(K)value.Results:In highly myopic eyes,despite good agreement between TK and K(P>0.05),larger differences between the two were associated with smaller central corneal thickness(P<0.05).As to the refractive errors,TK method showed no differences compared to K method.The XGBoost,RBF 3.0 and Kane ranked top three when considering SDs of PEs.Using TK value,the XGboost calculator was comparable with the RBF 3.0 formula(P>0.05),which both presented smaller MedAEs than others(all P<0.05).As for the percentage of eyes within±0.50 D or±0.75 D of PE,the XGBoost TK showed comparable percentages with the RBF 3.0 TK formula(74.76%vs.66.99%,or 90.29%vs.87.38%,P>0.05),and statistically larger percentages than the other eight formulas(P<0.05).Conclusions:Highly myopic eyes with thinner corneas tend to have larger differences between TK and K.The XGboost enhancement calculator and RBF 3.0 formula using TK showed the most promising outcomes in highly myopic eyes.展开更多
AIM: To examine the refractive prediction error in high myopic eyes after phacovitrectomy.METHODS: This retrospective comparative case series included 91 eyes(18 high myopic eyes and 73 non-high myopic eyes) of 91 pat...AIM: To examine the refractive prediction error in high myopic eyes after phacovitrectomy.METHODS: This retrospective comparative case series included 91 eyes(18 high myopic eyes and 73 non-high myopic eyes) of 91 patients who underwent successful phacovitrectomy(phacoemulsification, intraocular lens implantation, and pars plana vitrectomy). The high myopic eyes were defined as the eye with more than 26.0mm of axial length. The postoperative prediction error of mean error and mean absolute error were evaluated at4 mo postoperatively. Axial length and keratometry measurement were performed preoperatively and 4mo postoperatively using the IOL Master.RESULTS: The refractive outcome after phacovitrectomy showed significantly greater myopic shift in the high myopic eyes [-1.08 ±0.87 diopters(D)] than that in the non-high myopic eyes(-0.43 ±0.63 D, P =0.004). Axial length and keratometric value in the high myopic eyes were significantly increased(P =0.043, 0.037 respectively),whereas those in the non-high myopic group were not significantly increased(P =0.135, 0.347 respectively). The change of the axial length in the myopic eye(0.46±0.28 mm)was greater than that in the non- high myopic eye(0.11 ± 0.34 mm; P <0.001).CONCLUSION: High myopic eyes showed more myopic shift than non-high myopic eyes after phacovitrectomy.The cause of myopic shift in high myopic eyes seems tobe attributed to actual elongation of the axial length in high myopia.展开更多
AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean a...AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1 y were included. In all cases, a corneal curvature analysis was performed with IOL-Master(IOLM), iDesign 2(ID2), and Sirius systems(SIR). Differences between instruments for flattest(K1) and steepest(K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity(Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21(P<0.001),-0.12±0.36(P=0.046) and-0.32±0.36 D(P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33(P<0.001),-0.08±0.43(P=0.265) and-0.39±0.38 D(P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance(0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis(26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2(0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provideby the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.展开更多
AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation...AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P >0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P <0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.展开更多
AIM: To investigate the ocular development of patients who had unilateral congenital cataract(CC) combined with persistent fetal vasculature(PFV).METHODS: This cross-sectional, observational study included patients wh...AIM: To investigate the ocular development of patients who had unilateral congenital cataract(CC) combined with persistent fetal vasculature(PFV).METHODS: This cross-sectional, observational study included patients who had unilateral CC and PFV and those with isolated unilateral CC.Axial length(AL), keratometry, anterior chamber depth(ACD), lens thickness, and vitreous length were obtained.The ocular biometric parameters of the affected eyes of patients with CC and PFV were compared with the fellow eyes and with the affected eyes of patients with isolated CC.RESULTS: A total of 110 patients were included and divided into 4 groups: group 1(18 patients with CC and PFV, <24 mo), group 2(22 patients with CC and PFV, ≥24 mo), group 3(35 patients with CC, <24 mo), and group 4(35 patients with CC, ≥24 mo).The ALs of the affected eyes were shorter than those of the fellow eyes in group 1(20.02±1.06 vs 20.66±0.63 mm, P=0.025).While the ALs of the affected eyes were longer than those of the fellow eyes in group 2(23.18±2.00 vs 22.31±1.06 mm, P=0.044) and group 4(22.64±1.80 vs 22.02±1.01 mm, P=0.033).The keratometries of the affected eyes were steeper than those of the fellow eyes in group 2(44.78±1.66 vs 43.83±1.38 D,P=0.041) and group 4(43.76±1.91 vs 43.34±1.46 D, P=0.043).No difference of ACDs between two eyes was found in all groups(all P>0.05).CONCLUSION: Compared with the fellow eyes, the ALs of the eyes with unilateral CC and PFV are shorter in patients younger than 24 mo and longer in those older than 24 mo;the keratometries of the eyes with unilateral CC and PFV are steeper in patients older than 24 mo and similar with those younger than 24 mo.These findings provide further understanding of ocular development in patients with both CC and PFV.展开更多
AIM:To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking(CXL)with total corneal refractive power(TCRP)using ray tracing method.METHODS:A total of 40 eyes of 30 consecutive p...AIM:To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking(CXL)with total corneal refractive power(TCRP)using ray tracing method.METHODS:A total of 40 eyes of 30 consecutive patients who underwent CXL for progressive keratoconus were retrospectively enrolled.The following keratometric parameters provided by Pentacam HR,including maximum keratometry(Kmax),steepest keratometry(Ksteep),3 mm zonal TCRP centered over corneal apex(TCRPapex,zone 3 mm),zonal mean keratometry and TCRP centered over corneal cone(Kmcone,zone and TCRPcone,zone 1,2,3 mm)were evaluated preoperatively and 1,3,6,and 12 mo postoperatively.Groups 1 and 2 were defined based on Kmax at postoperative 1 mo as improved(the initial improvement group)or worsen(the initial deterioration group)compared to the preoperative level.RESULTS:In the overall group,only keratometric parameters based on ray tracing method displayed significant improvement early at 3 mo postoperatively,in which TCRPcone,zone 1 mm and 2 mm exhibited the largest flattening(0.57 D and 0.53 D,respectively).In Group 1,only Kmax,Kmcone,zone 2 mm and TCRPcone,zone 2 mm showed significant improvement initially at 1 mo postoperatively,in which Kmax exhibited the largest improvement(1.05 D),followed by TCRPcone,zone 2 mm(0.82 D).In Group 2,only keratometric parameters based on ray tracing method and Kmcone,zone 3 mm showed slight but not significant improvement early at 3 mo,in which TCRPcone,zone 3 mm displayed the most improvement(0.19 D),followed by TCRPcone,zone 2 mm(0.15 D).CONCLUSION:The findings indicate that a 2 mm zonal TCRP centered over Kmax could earlier detect keratometric improvement by CXL compared to other commonly used parameters in mild to moderate keratoconic eyes.展开更多
Aim: The purpose of this study was to compare measurements of CCT in emmetropia and patient with refractive anomalies. Methods: We represent a retrospective research which was conducted at the University Clinical Cent...Aim: The purpose of this study was to compare measurements of CCT in emmetropia and patient with refractive anomalies. Methods: We represent a retrospective research which was conducted at the University Clinical Center of Kosovo (UCCK). In this study were included 80 patients, divided into two groups: test and a control group. Mean age was (M = 25.90, DS = 7.16), men (N = 41% or 51.3%) and women (N = 39% or 48%). Results: Results show that there were no differences in the CCT, Hyperopic (M = 545.21 DS = 52.24), Myopic (M = 547.90 DS = 47.93) and Emmetropic (M = 550.75 DS = 41.29). After measuring of the longitudinal axis and analyzing the data by means of Anova test, it appeared to be a significant difference between the analyzed groups, Hyperopic (M = 21.99, DS = 1.27), Myopics (M = 23.21, DS = 1.24), Emmetropic (M = 22.36, DS = 0.81). Results also revealed that there is correlation between the CCT and IOP, where increase CCT decreases IOP and vice versa (r = -0.26, p = 0.01). Conclusion: The results have shown that CCT is thinner in myopic but does not show correlation with hypermetropic and emmetropic. While during the measurement of central corneal thickness and eye tension it is found that there is a negative correlation between them. Keratometry has a negative correlation with CCT. While there was no correlation between CCT and age. Given the role of CCT in interpreting IOP values, it is recommended to perform a systematic CCT measurement in routine clinical practice, which would assist in the diagnosis of ocular hypertension.展开更多
Background:This review aims to explain the reasons why intraocular lens(IOL)power calculation is challenging in eyes with previous corneal refractive surgery and what solutions are currently available to obtain more a...Background:This review aims to explain the reasons why intraocular lens(IOL)power calculation is challenging in eyes with previous corneal refractive surgery and what solutions are currently available to obtain more accurate results.Review:After IOL implantation in eyes with previous LASIK,PRK or RK,a refractive surprise can occur because (i)the altered ratio between the anterior and posterior corneal surface makes the keratometric index invalid;(ii)the corneal curvature radius is measured out of the optical zone;and (iii)the effective lens position is erroneously predicted if such a prediction is based on the post-refractive surgery corneal curvature.Different methods are currently available to obtain the best refractive outcomes in these eyes,even when the perioperative data(i.e.preoperative corneal power and surgically induced refractive change)are not known.In this review,we describe the most accurate methods based on our clinical studies.Conclusions:IOL power calculation after myopic corneal refractive surgery can be calculated with a variety of methods that lead to relatively accurate outcomes,with 60 to 70%of eyes showing a prediction error within 0.50 diopters.展开更多
文摘AIM:To find a simple mathematical correlation between the lens base curve(BC) and keratometry findings(krf).METHODS:This retrospective study included 400 keratoconic eyes(350 patients) previously fit with rigid contact lenses at an academic eye center over a five year period.The patients were classified into five groups based on the keratometry findings(krf<7,krf:7-8,krf>8,krf-krs(difference between two keratometry;flat and steep)= 0.3-0.6,krf-krs >0.6mm as groups 1 to 5,respectively.Multivariate linear regression and Munro's correlation coefficient were employed to defer the formulas.RESULTS:A linear correlation could be found in all groups except for patients in group 3.For group 1,BC=0.211×krf+ 5.904.For group 2,BC=0.456×krf+4.160.For group 4,BC= 0.321×krf+5.219.For group 5,BC=0.337×krf+ 5.090.CONCLUSION:The development of new formulas for RGP fitting enables ophthalmologists to work with confidence and prevents unnecessary and frequent lens trials.The customary lens fitting methods are needed to be replaced by new formulas,which help to save time and costs.
基金Supported by a research grant from the Portuguese Society of Ophthalmology。
文摘AIM:To evaluate inter-device agreement of anterior keratometry obtained by the IOLMaster 500 and Pentacam HR in type 2 diabetic and non-diabetic patients.METHODS:Corneal measurements were sequentially performed in 60 diabetes mellitus(DM)and 48 age and sex-matched controls undergoing cataract surgery.Variables recorded included flat and steep keratometry,mean keratometry(Km),astigmatism magnitude,axis location,JO and J45 components.Bland-Altman plots and intraclass correlation coefficients were used for examination of agreement.Subgroup analyses were performed for astigmatism magnitude,diabetes duration,hemoglobin A1c(HbA1c)levels and diabetic retinopathy(DR)stage.RESULTS:Agreement for Km and astigmatism magnitude were considered good and moderate,with 95%limits of agreement(LoA)of-1.09 to 1.23 diopters(D)and-0.83 to 0.86 D in DM group,respectively;and-0.59 to 0.72 D and-0.98 to 0.75 D in non-DM group,respectively.In contrast,the 95%LoA for corneal axis exceeded the clinically relevant margins in both groups.In the total sample,only 41 eyes(38%)had a smaller than 5-degree difference.Diabetes duration,HbA1c levels and DR stage were not found to significantly affect agreement.Logistic regression showed that higher corneal power(P=0.021)and astigmatism magnitude(P=0.011)were associated with a decreased risk of having a difference in axis location greater than 10-degrees.CONCLUSION:In both groups,IOLMaster and Pentacam agree well for corneal power and moderately for astigmatism.However,axis location disagreement is frequent in eyes with flatter corneas and small amounts of astigmatism.
文摘To evaluate the effect of preoperative keratometry on visual and refractive outcomes after Myopic LASER in Situ Keratomileusis (LASIK) in eyes with preoperative spherical equivalent (SE) of -6.00D or less. Material and Methods: A retrospective study enrolling clinical records of 482 eyes of 275 patients with myopia who underwent LASIK between 2009 and 2016. Subjects were grouped according to the degree of preoperative mean keratometry (Km), into three groups: Group 1 (Flat Cornea): Km ≤ 42.00 diopters (D);Group 2: 42.00 46.00D;Group 3 (Steep Cornea): Km ≥ 46.00D. To evaluate the prognostic impact of keratometry in Myopic LASIK, we considered the results measured at 6 months postoperatively, including uncorrected distance visual acuity (UDVA), postoperative sphere, cylinder, SE and its variation. Results: The mean preoperative SE was -3.91 ± 1.54D, ranging between -0.88 and -6.00D. The percentage of eyes achieving a postoperative SE of ±0.50D was 39.5%, 31.8% and 26% in groups 1, 2 and 3 respectively. Moreover, in group 3, 14.3% of the eyes had a residual SE of -2.00D or greater, contrasting with the groups 1 and 2 with only 6% - 7%. These results were found to be statistically significant. Concerning UDVA, eyes achieving 20/25 or more were 81.5%, 81.8% and 71.5%, and 20/50 or less were 6.7%, 6.2% and 11.7% in groups 1, 2 and 3 respectively. Conclusions: Myopic eyes with steeper corneas seem to have greater tendency to undercorrection, also presenting worse visual outcomes.
基金This work was supported in part by the Medical and Health Science and Technology Program of Zhejiang Province(2019KY111)Foundation of Wenzhou City Science&Technology Bureau(Y20180174)+3 种基金Zhejiang Provincial Key Research and Development Program(2018C03012)Zhejiang Provincial High-level Talents Program(2017–102)Wenzhou Key Team of Scientific and Technological Innovation(C20170002)The contribution from the G.B.Bietti Foundation was supported by the Italian Ministry of Health and Fondazione Roma.
文摘Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children.Methods:Pachymetric and keratometric maps for both systems were evaluated.Central,midperipheral and peripheral corneal thickness(CT),keratometry and astigmatism power vectors were recorded.The three outcomes yielded by the same observer were used to assess intraobserver repeatability.The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility.Within-subject standard deviation,test-retest repeatability(TRT)and coefficient of variation(CoV)were used to analyze the intraobserver repeatability and interobserver reproducibility.Paired T-test and Bland-Altman were used to appraise interdevice agreement.Results:Seventy-eight eyes of 78 children were included.The CoV was≤2.12 and 1.10%,respectively,for repeatability and reproducibility.TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements.The SS-OCT device generated higher precision when acquiring CT data,whereas Scheimpflug system showed higher reliability when measuring corneal keratometry.Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device(P<0.001),the central and thinnest CT values were still of high agreement.The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas.Conclusions:The precision of CT measurements by SS-OCT was higher,while the reliability of keratometry measurements by the Scheimpflug system was higher in children.Apart from the measured values in the central corneal region,the thickness and keratometry readings should not be considered interchangeable between the two systems.
基金supported in part by the Medical and Health Science and Technology Program of Zhejiang Province(2019kY111)Foundation of Wenzhou City Science&Technology Bureau(Y20180174)+2 种基金Zhejiang Provincial Key Researchand Development Program(2018C03012)Zhejiang Provincial High-level Talents Program(2017-102)WenzhouKey Teamof Scientific and Technological Innovation(C20170002).
文摘Purpose:To assess the repeatability and reproducibility of swept-source optical coherence tomography(SS-OCT)and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children.Methods:Pachymetric and keratometric maps for both systems were evaluated.Central,midperipheral and peripheral corneal thickness(CT),keratometry and astigmatism power vectors were recorded.The three outcomes yielded by the same observer were used to assess intraobserver repeatability.The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility.Within-subject standard deviation,test-retest repeatability(TRT)and coefficient of variation(CoV)were used to analyze the intraobserver repeatability and interobserver reproducibility.Paired T-test and Bland-Altman were used to appraise interdevice agreement.Results:Seventy-eight eyes of 78 children were included.The CoV was≤2.12 and 1.10%,respectively,for repeatability and reproducibility.TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements.The SS-OCT device generated higher precision when acquiring CT data,whereas Scheimpflug system showed higher reliability when measuring corneal keratometry.Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device(P<0.001),the central and thinnest CT values were still of high agreement.The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas.Conclusions:The precision of CT measurements by SS-OCT was higher,while the reliability of keratometry measurements by the Scheimpflug system was higher in children.Apart from the measured values in the central corneal region,the thickness and keratometry readings should not be considered interchangeable between the two systems.
基金Supported by the Hospital Founding of Beijing Tongren Hospital(No.2021-YJJ-PY-002)。
文摘AIM:To analyze the differences,agreements,and correlation among total corneal power parameters generated by different instruments after myopic keratorefractive surgery.METHODS:The prospective cross-sectional study included patients who underwent myopic keratorefractive surgery and received measurements of corneal power 3mo after surgery.Automated keratometer was used for the measurement of simulated keratometry(Sim K),sweptsource optical coherence tomography(SS-OCT)based biometer for total keratometry(TK),anterior segment-OCT for real keratometry(RK),and Scheimpflug keratometer for the true net power(TNP),the total corneal refractive power(TCRP)and equivalent K-readings(EKR).The differences among these parameters were analyzed,and the agreements and correlation between Sim K and other total corneal power parameters were investigated.RESULTS:A total of 70 eyes of 70 patients after myopic keratorefractive surgery were included.The evaluated corneal power parameters were as follows:Sim K 38.32±1.93 D,TK 37.54±2.12 D,RK 36.64±2.09 D,TNP 36.56±1.97 D,TCRP 36.70±2.01 D,and EKR 37.55±2.00 D.Pairwise comparison showed that there were significant differences(P<0.001)among all parameters except for between TK and EKR,RK and TNP,RK and TCRP(P=1.000,1.000,1.000,respectively).The limits of agreement between Sim K and TK,RK,TNP,TCPR,and EKR were 1.08,1.08,1.43,1.48,and 1.73 D,respectively.All parameters showed good correlation with Sim K,and the correlation coefficients were 0.995,0.994,0.983,0.982,and 0.975.CONCLUSION:Among the corneal power parameters after myopic keratorefractive surgery,the value of Sim K is the largest,followed by TK and EKR,with TCRP,RK,and TNP being the smallest.The differences among the parameters may be attributable to the different calculation principles.Correct understanding and evaluation of corneal power parameters can provide a theoretical basis for taking advantage of the total corneal power to improve the accuracy of intraocular lens calculation after keratorefractive surgery.
基金supported by research grants from the National Natural Science Foundation of China(Grant Nos.82122017,81870642,81970780 and 81670835)Science and Technology Innovation Action Plan of Shanghai Science and Technology Commission(Grant Nos.19441900700 and 21S31904900)+1 种基金Clinical Research Plan of Shanghai Shenkang Hospital Development Center(Grant Nos.SHDC2020CR4078 and SHDC12019X08)the Fudan University“Outstanding 2025”Program.
文摘Background:The accuracy of using total keratometry(TK)value in recent IOL power calculation formulas in highly myopic eyes remained unknown.Methods:Highly myopic patients who underwent uneventful cataract surgery were prospectively enrolled in this prospective comparative study.At one month postoperatively,standard deviation(SD)of the prediction errors(PEs),mean and median absolute error(MedAE)of 103 highly myopic eyes were back-calculated and compared among ten formulas,including XGboost,RBF 3.0,Kane,Barrett Universal II,Emmetropia Verifying Optical 2.0,Cooke K6,Haigis,SRK/T,and Wang-Koch modifications of Haigis and SRK/T formulas,using either TK or standard keratometry(K)value.Results:In highly myopic eyes,despite good agreement between TK and K(P>0.05),larger differences between the two were associated with smaller central corneal thickness(P<0.05).As to the refractive errors,TK method showed no differences compared to K method.The XGBoost,RBF 3.0 and Kane ranked top three when considering SDs of PEs.Using TK value,the XGboost calculator was comparable with the RBF 3.0 formula(P>0.05),which both presented smaller MedAEs than others(all P<0.05).As for the percentage of eyes within±0.50 D or±0.75 D of PE,the XGBoost TK showed comparable percentages with the RBF 3.0 TK formula(74.76%vs.66.99%,or 90.29%vs.87.38%,P>0.05),and statistically larger percentages than the other eight formulas(P<0.05).Conclusions:Highly myopic eyes with thinner corneas tend to have larger differences between TK and K.The XGboost enhancement calculator and RBF 3.0 formula using TK showed the most promising outcomes in highly myopic eyes.
文摘AIM: To examine the refractive prediction error in high myopic eyes after phacovitrectomy.METHODS: This retrospective comparative case series included 91 eyes(18 high myopic eyes and 73 non-high myopic eyes) of 91 patients who underwent successful phacovitrectomy(phacoemulsification, intraocular lens implantation, and pars plana vitrectomy). The high myopic eyes were defined as the eye with more than 26.0mm of axial length. The postoperative prediction error of mean error and mean absolute error were evaluated at4 mo postoperatively. Axial length and keratometry measurement were performed preoperatively and 4mo postoperatively using the IOL Master.RESULTS: The refractive outcome after phacovitrectomy showed significantly greater myopic shift in the high myopic eyes [-1.08 ±0.87 diopters(D)] than that in the non-high myopic eyes(-0.43 ±0.63 D, P =0.004). Axial length and keratometric value in the high myopic eyes were significantly increased(P =0.043, 0.037 respectively),whereas those in the non-high myopic group were not significantly increased(P =0.135, 0.347 respectively). The change of the axial length in the myopic eye(0.46±0.28 mm)was greater than that in the non- high myopic eye(0.11 ± 0.34 mm; P <0.001).CONCLUSION: High myopic eyes showed more myopic shift than non-high myopic eyes after phacovitrectomy.The cause of myopic shift in high myopic eyes seems tobe attributed to actual elongation of the axial length in high myopia.
基金supported by the Ministry of Economy,Industry and Competitiveness of Spain within the program Ramón y Cajal,RYC-2016-20471Additionally he received an unrestricted grant from Johnson and Johnson Vision for the performance of this research
文摘AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles.METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1 y were included. In all cases, a corneal curvature analysis was performed with IOL-Master(IOLM), iDesign 2(ID2), and Sirius systems(SIR). Differences between instruments for flattest(K1) and steepest(K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity(Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21(P<0.001),-0.12±0.36(P=0.046) and-0.32±0.36 D(P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33(P<0.001),-0.08±0.43(P=0.265) and-0.39±0.38 D(P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance(0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis(26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2(0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provideby the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.
文摘AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P >0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P <0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.
基金Supported by the National Key R&D Program of China (No.2020YFC2008200)the National Natural Science Foundation of China (No.81970813+4 种基金No.81970778No.82000946)the Natural Science Foundation of Guangdong Province (No.2020A1515010987No.2021A1515012238)Guangzhou Municipal Science and Technology Project (No.201904010062)。
文摘AIM: To investigate the ocular development of patients who had unilateral congenital cataract(CC) combined with persistent fetal vasculature(PFV).METHODS: This cross-sectional, observational study included patients who had unilateral CC and PFV and those with isolated unilateral CC.Axial length(AL), keratometry, anterior chamber depth(ACD), lens thickness, and vitreous length were obtained.The ocular biometric parameters of the affected eyes of patients with CC and PFV were compared with the fellow eyes and with the affected eyes of patients with isolated CC.RESULTS: A total of 110 patients were included and divided into 4 groups: group 1(18 patients with CC and PFV, <24 mo), group 2(22 patients with CC and PFV, ≥24 mo), group 3(35 patients with CC, <24 mo), and group 4(35 patients with CC, ≥24 mo).The ALs of the affected eyes were shorter than those of the fellow eyes in group 1(20.02±1.06 vs 20.66±0.63 mm, P=0.025).While the ALs of the affected eyes were longer than those of the fellow eyes in group 2(23.18±2.00 vs 22.31±1.06 mm, P=0.044) and group 4(22.64±1.80 vs 22.02±1.01 mm, P=0.033).The keratometries of the affected eyes were steeper than those of the fellow eyes in group 2(44.78±1.66 vs 43.83±1.38 D,P=0.041) and group 4(43.76±1.91 vs 43.34±1.46 D, P=0.043).No difference of ACDs between two eyes was found in all groups(all P>0.05).CONCLUSION: Compared with the fellow eyes, the ALs of the eyes with unilateral CC and PFV are shorter in patients younger than 24 mo and longer in those older than 24 mo;the keratometries of the eyes with unilateral CC and PFV are steeper in patients older than 24 mo and similar with those younger than 24 mo.These findings provide further understanding of ocular development in patients with both CC and PFV.
基金National Natural Science Foundation of China(No.81970769)Hunan Province Technology Innovation Guidance Program(No.2018SK50108)+1 种基金Wuhan City Medicine Research Project(No.WX19C12)Ophthalmology and Otorhinolaryngology College of Hubei University of Science and Technology Research Development Fund Project(No.2020XZ38)。
文摘AIM:To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking(CXL)with total corneal refractive power(TCRP)using ray tracing method.METHODS:A total of 40 eyes of 30 consecutive patients who underwent CXL for progressive keratoconus were retrospectively enrolled.The following keratometric parameters provided by Pentacam HR,including maximum keratometry(Kmax),steepest keratometry(Ksteep),3 mm zonal TCRP centered over corneal apex(TCRPapex,zone 3 mm),zonal mean keratometry and TCRP centered over corneal cone(Kmcone,zone and TCRPcone,zone 1,2,3 mm)were evaluated preoperatively and 1,3,6,and 12 mo postoperatively.Groups 1 and 2 were defined based on Kmax at postoperative 1 mo as improved(the initial improvement group)or worsen(the initial deterioration group)compared to the preoperative level.RESULTS:In the overall group,only keratometric parameters based on ray tracing method displayed significant improvement early at 3 mo postoperatively,in which TCRPcone,zone 1 mm and 2 mm exhibited the largest flattening(0.57 D and 0.53 D,respectively).In Group 1,only Kmax,Kmcone,zone 2 mm and TCRPcone,zone 2 mm showed significant improvement initially at 1 mo postoperatively,in which Kmax exhibited the largest improvement(1.05 D),followed by TCRPcone,zone 2 mm(0.82 D).In Group 2,only keratometric parameters based on ray tracing method and Kmcone,zone 3 mm showed slight but not significant improvement early at 3 mo,in which TCRPcone,zone 3 mm displayed the most improvement(0.19 D),followed by TCRPcone,zone 2 mm(0.15 D).CONCLUSION:The findings indicate that a 2 mm zonal TCRP centered over Kmax could earlier detect keratometric improvement by CXL compared to other commonly used parameters in mild to moderate keratoconic eyes.
文摘Aim: The purpose of this study was to compare measurements of CCT in emmetropia and patient with refractive anomalies. Methods: We represent a retrospective research which was conducted at the University Clinical Center of Kosovo (UCCK). In this study were included 80 patients, divided into two groups: test and a control group. Mean age was (M = 25.90, DS = 7.16), men (N = 41% or 51.3%) and women (N = 39% or 48%). Results: Results show that there were no differences in the CCT, Hyperopic (M = 545.21 DS = 52.24), Myopic (M = 547.90 DS = 47.93) and Emmetropic (M = 550.75 DS = 41.29). After measuring of the longitudinal axis and analyzing the data by means of Anova test, it appeared to be a significant difference between the analyzed groups, Hyperopic (M = 21.99, DS = 1.27), Myopics (M = 23.21, DS = 1.24), Emmetropic (M = 22.36, DS = 0.81). Results also revealed that there is correlation between the CCT and IOP, where increase CCT decreases IOP and vice versa (r = -0.26, p = 0.01). Conclusion: The results have shown that CCT is thinner in myopic but does not show correlation with hypermetropic and emmetropic. While during the measurement of central corneal thickness and eye tension it is found that there is a negative correlation between them. Keratometry has a negative correlation with CCT. While there was no correlation between CCT and age. Given the role of CCT in interpreting IOP values, it is recommended to perform a systematic CCT measurement in routine clinical practice, which would assist in the diagnosis of ocular hypertension.
基金The contribution of G.B.Fondazione Bietti IRCCS was supported by the Italian Ministry of Health and Fondazione Roma.
文摘Background:This review aims to explain the reasons why intraocular lens(IOL)power calculation is challenging in eyes with previous corneal refractive surgery and what solutions are currently available to obtain more accurate results.Review:After IOL implantation in eyes with previous LASIK,PRK or RK,a refractive surprise can occur because (i)the altered ratio between the anterior and posterior corneal surface makes the keratometric index invalid;(ii)the corneal curvature radius is measured out of the optical zone;and (iii)the effective lens position is erroneously predicted if such a prediction is based on the post-refractive surgery corneal curvature.Different methods are currently available to obtain the best refractive outcomes in these eyes,even when the perioperative data(i.e.preoperative corneal power and surgically induced refractive change)are not known.In this review,we describe the most accurate methods based on our clinical studies.Conclusions:IOL power calculation after myopic corneal refractive surgery can be calculated with a variety of methods that lead to relatively accurate outcomes,with 60 to 70%of eyes showing a prediction error within 0.50 diopters.
