The influencing factors of surgically induced astigmatism in phacoemulsification / 西安交通大学学报(医学版)

【Objective】 To investigate the influencing factors of surgically induced astigmatism (SIA) in phacoemulsification. 【Methods】 Cataract phacoemulsification was performed in 69 patients with regular corneal astigmatism from December 2021 to March 2022. SIA of the anterior corneal surface, posterior corneal surface and simulated keratometry (SimK) in the diameter range of 3 mm, 5 mm and 7 mm centered at the apex of the cornea was observed. Pearson correlation analysis was used to analyze SIA with age, axial length (AL), anterior chamber depth (ACD), white-to-white (WTW), and central corneal thickness (CCT). Multiple linear regression was used to analyze the influencing factors of SIA. 【Results】 The mean age of the 69 patients was (63.25±14.74) years old, and 28 (40.58%) were male. The analysis found that the |SIA| of SimK was negatively correlated with WTW (r=-0.265, P=0.028), the |SIA| of 3 mm, 5 mm, 7 mm anterior surface was negatively correlated with WTW (r=-0.320, P=0.007; r=-0.337, P=0.005; r=-0.287, P=0.017), and the |SIA| of 3 mm, 5 mm, 7 mm posterior surface was negatively correlated with AL (r=-0.390, P=0.001; r=-0.352, P=0.003; r=-0.317, P=0.008). Multiple regression analysis showed that WTW was negatively correlated with |SIA| of SimK, 3 mm, 5 mm, 7 mm anterior surface and 3 mm posterior surface (B=-0.261, P=0.047; B=-0.387, P=0.016; B=-0.323, P=0.009; B=-0.297, P=0.041; B=-0.085, P=0.049). WTW was positively correlated with XSIA of 3 mm anterior surface, YSIA of 5 mm, and 7 mm anterior surface (B=0.347, P=0.040; B=0.318, P=0.034; B=0.403, P=0.010). AL was negatively correlated with |SIA| on the posterior surface of 3 mm and 5 mm (B=-0.023, P=0.021; B=-0.034, P=0.030). 【Conclusion】 During cataract surgery, the effect of ocular biological parameters such as axial length and corneal diameter on SIA should be considered.

Prediction of vault after implantable collamer lens implantation and its research progress / 国际眼科杂志(Guoji Yanke Zazhi)

Myopia is considered to be a disease occurred under the influence of genetic and environmental factors, and it can only be restored by corrective surgeries. The current surgical methods include laser surgeries and phakic intraocular lens(PIOL)implantation, and PIOL has the advantages of wide range of correction, repeatable procession and small damage to corneal tissue. Furthermore, good visual acuity can be achieved after implantation of intraocular lens. Implantable collamer lens(ICL)is the most common surgical method in this group. The vertical distance between the highest point of the posterior central surface of the implanted lens and the anterior surface of the crystalline lens is called vault. It will cause serious complications if the vault turns out to be abnormal. Up to now, there is no optimal prediction method. This research focuses on vault, discusses the ideal range of postoperative vault, the safety and effectiveness of this surgery, and analyzes the existing prediction methods to provide directions for future clinical research.

Agreement between the biometric measurements used to calculate the size of the implantable collamer lenses measured with four different technologies

Purpose: To evaluate the agreement between the biometric measurements used to calculate the size of the implantable collamer lenses (ICL) with different technologies: swept?source optical coherence tomography, spectral domain optical coherence tomography, and Scheimpflug tomography. Methods: This retrospective observational study included subjects undergoing refractive surgery with posterior chamber phakic IOL implantation to correct their myopia. The anterior chamber depth (ACD) and the horizontal white to white (WTW) or the angle to angle (ATA) distance were measured with the following four devices: the IOLMaster 700 biometer (Carl Zeiss Meditec, Jena, Germany), based on swept?source optical coherence tomography; the Cirrus and Visante optical coherence tomographs (Carl Zeiss Meditec) based on low?coherence interferometry; and the Pentacam rotating Scheimpflug camera (Oculus, Wetzlar, Germany). Results: In the horizontal corneal diameter measurements, there were statistically significant differences between Pentacam–IOLMaster 700 pair (P < 0.001) and Pentacam–Visante pair (P < 0.001). WTW from CIRRUS showed the lowest correlation when paired with Pentacam and IOLMaster 700 (R2 = 0.452 and 0.385 for Visante and R2 = 0.494 and 0.426 for Cirrus). Regarding the linear correlation of the ACD measurements, all pairs of devices were statistically significant and all of them showed a very good correlation index. Conclusion: There is a good agreement between the different devices under evaluation for ACD measurements. As for WTW, the values measured with the different devices showed large discrepancies with low correlation levels, especially when comparing the tomographs with the other devices under evaluation

Confounding sizing in posterior chamber phakic lens selection due to white-to-white measurement bias

Purpose: To assess the agreement in the white-to-white (WTW) measurement with two different devices, the reproducibility and the probability of confusing sizing (PCS) in selecting a different implantable collamer lens (ICL). Study Design: Retrospective observational case series. Methods: Images of 192 eyes were captured with both devices. The WTW was measured automatically (OA) and manually (OM) with the Orbscan and Keratograph (KA and KM) by one examiner who repeated a total of four measures. A second examiner conducted a single manual measure for each device over the same image. The ICL sizing was computed for each measure of WTW and the PCS was calculated as the percentage of cases for which the confronted or repeated measure resulted in a different size of the ICL. The critical WTWs with highest PCS were identified. Results: KM overestimated the WTW versus OM in 0.13 ± 0.18 mm (P < 0.001) but not in the automated method comparison, 0.01 ± 0.19 mm (P = 0.58). Inter-examiner reproducibility (R) was higher with OM than with KM, and the intra-examiner R decreased with the average of two measures in both cases. The PCS was higher with the increase of mean differences, the limits of agreement (LoAs), and R. WTWs from 11.1 to 11.2 mm, 11.6 to 11.7 mm, and 12.3 to 12.4 mm resulted in higher PCS. Conclusion: The mean difference is not enough to apply conversions between devices and the LoAs and R should be considered. Special attention should be taken for WTWs with higher PCS.

A Comparison of Axial Length, Keratometry, and Measured White-to-white Using Different Devices

PURPOSE: To compare the accuracy and clinical usefulness of various devices by measuring axial length, keratometry, and white-to-white. METHODS: In 64 eyes of 56 cataract patients, axial length was measured using Galilei™, Lenstar®, and A-scans, and keratometry was measured using Galilei™, Lenstar®, and ARK. In 86 eyes of 74 cataract patients, white-to-white was measured using Galilei™ and Lenstar®. RESULTS: The average axial length measurements using Galilei™, Lenstar®, and A-scans were significantly correlated (p < 0.001), but without a statistically significant difference (p = 0.611). The 95% agreement range was the smallest at 0.22 mm for the Lenstar® and A-scans. The average mean K using Galilei™, Lenstar®, and ARK were significantly correlated (p < 0.001), but without a statistically significant difference (p = 0.657). The 95% agreement range was relatively small at 1.83 D for Lenstar® and ARK. The average white-to-white using Galilei™ and Lenstar® were significantly correlated (p < 0.001), with a statistically significant difference (p = 0.011). The 95% agreement range was 2.20 mm. CONCLUSIONS: Axial length, keratometry, and white-to-white measured by different devices were highly correlated and were not statistically different; however, agreement was low between measurements. It is therefore important to consider these findings when using them equally.

The Angle Kappa in Dominant and Non-Dominant Eye

PURPOSE: To evaluate differences between dominant and non-dominant eyes by analyzing angle kappa in dominant and non-dominant eyes. METHODS: Fifty-seven subjects who had best corrected visual acuity 20/20 in the better-seeing eye and no underlying ocular disease were recruited. Ocular dominance was determined using the hole-in-the-card test. Corneal topography, refractive error, intraocular pressure (IOP), and axial length were evaluated in both eyes. RESULTS: On corneal topography examination, the angle kappa and white-to-white measurements were significantly smaller in the dominant eye than the non-dominant eye (p = 0.013 and p = 0.045, respectively). However, no significant differences in sim K's' astigmatism (p = 0.210), central corneal thickness (p = 0.533), and anterior chamber depth (p = 0.216) were observed. In addition, cylindrical powers of the subjects measured by autorefraction (AR) were significantly lower in the dominant eye (p = 0.026); however no differences in spherical equivalent measured by AR (p = 0.061), IOP measured using pneumonic tonometer (p = 0.536), or axial length measured using laser biometry (p = 0.093) were observed. CONCLUSIONS: In this study, we found the angle kappa a new factor in determining the dominant and non-dominant eye. Difference in axial length and spherical equivalent between dominant and non-dominant eye may be associated with the difference in angle kappa.

Discrepancy of sulcus-to-sulcus diameter and its relationship with white-to-white diameter in high myopic eyes / 中华实验眼科杂志

Background Horizontal sulcus-to-sulcus (STS) and white-to-white diameter are important parameters for designing the proper size of collamer implantable contact lens (ICL).Inappropriate size of ICL may induce the complications postoperatively.Several previous studies compare horizontal STS and white-to-white diameter in normal eyes have been reported,but seldom in high myopic eyes.Objective This study was to investigate the discrepancy of STS diameters in 4 axes and analyze the relationship between horizontal STS diameter and white-towhite diameter in high myopia eyes.Methods The STS diameters in 4 axes (45,90,135 and 180 degrees) and the white-to-white diameters were measured in 48 eyes of 26 high myopia patients using the 50 MHz ultrasound biomicroscopy (UBM),the Orbscan-Ⅱ topography system,and the IOL Master,respectively.The mean spherical was (-12.93±3.87) diopters (D) (-8 to-20 D).Statistical evaluation was performed using the one-way ANOVA for comparison of measurement.The agreement of three devices was assessed using the Bland and Altman method.Results The mean STS diameter at 45,90,135 and 180 degrees was (12.06±0.50) mm,(12.27±0.50)mm,(12.03±0.46) mm and (11.84±0.47)mm,respectively.The 90 degree STS was significantly larger than other STS diameters (all at P＜0.05).The 180 degrees STS was significantly shorter than other STS diameters (all at P＜0.05).However,there was no significant difference between 45 degree STS and 135 degree STS (P=0.817).The mean WTW was (11.56±0.40) mm with Orbscan Ⅱ z topography system and (11.98±0.41) mm with IOLMaster.The WTW measured with Orbscan Ⅱ z was significantly shorter than the 180 degrees STS (t =-4.384,P =0.000).The WTW measured with IOLMaster was significantly larger than the 180 degrees STS (t =2.368,P =0.000).Bland-Altman analysis showed not very well agreement for measurements of WTW,STS between Orbscan Ⅱz and UBM,IOLMaster and UBM,Orbscan Ⅱ z and IOLMaster,the width of 95％ confidence interval (CI) were-0.57 to 1.12 mm,-0.96 to 0.67 mm,-0.73 to-0.13 mm,respectively.Conclusions The STS diameters in 4 different axes are not identical with each other in high myopia eyes.The longest STS is in the vertical meridian,the shortest STS is in the horizontal meridian.The WTW diameter measured with both Orbscan Ⅱ z and IOLMaster are not precise for calculating the horizontal STS in high myopia eyes.Three instruments cannot be interchanged for calculating the size of ICL.

Comparison of ocular anterior segment parameters measured by three kinds of biometric measuring methods in myopic eyes / 中华实验眼科杂志

Background It is essential to measure and assess the parameters of ocular anterior segment for refractive surgery in myopic eyes.Some different imaging devices can be used for biometric measurement of ocular anterior segment,but which is more accurate and convenient is still under investigation.Objective This study was to compare the anterior segment parameters in myopic eyes measured by anterior segment optical coherence tomography (AS-OCT),Orbscan topography and ultrasonic pachymetry (US).Methods One hundred and forty eyes of 70 myopic subjects with the diopter of-0.75 to-10.25 D,who intended to receive corneal refractive surgery in the Second Affiliated Hospital of Zhejiang University School of Medicine from November 2011 to May 2012,were retrospectively analyzed.Central corneal thickness (CCT) was measured using AS-OCT,Orbscan Ⅱ and US,respectively,and anterior chamber depth (ACD) was measured by AS-OCT and Orbscan Ⅱ,and the angle to angle (ATA) distance and corneal white-to-white corneal distance (WTW) were measured by AS-OCT and Orbscan Ⅱ,respectively.The parameters from different apparatuses were statistically compared.Results The mean CCT were (516.57±30.25) μm in AS-OCT,(523.68±31.87) μm in US and (514.69±38.40) μm in Orbscan Ⅱ,without significant difference among them (F =2.775,P =0.063).Then the patients were divided into three groups based on the US measurement of CCT (＜500 μm group,500-569 μm group,and ≥ 570 μm group).In the ＜500 μm group,there was a significant difference in the CCT among the three methods (F =22.236,P =0.000),significant differences were found between AS-OCT and Orbscan Ⅱ,or Orbscan Ⅱ and US(both at P＜0.05).In the 500-569 μm group,there was no significant difference in the CCT among the three methods (F =3.011,P =0.051).In the ≥ 570 μm group,there was a significant difference in the CCT among the three methods (F =4.133,P =0.021),a significant difference was found between AS-OCT and US(P＜0.05),but there was no significant difference between AS-OCT and Orbscan Ⅱ (P＞0.05).The ACD values measured by AS-OCT was (3.83±0.21) mm,which was higher than (3.75 ± 0.21) mm by Orbscan Ⅱ,with a significant difference between them (t =-8.520,P =0.000).In addition,the ATA value by AS-OCT (12.43 mm±0.74 mm) was higher than the WTW value (11.42 mm±0.33 mm) by OrbscanⅡ,with a significant difference between them(t=-18.088,P=0.000).Conclusions AS-OCT,US and Orbscan Ⅱ can offer accurate CCT value,and they can provide references to one another before refractive surgery.However,the ACD,ATA and WTW values by AS-OCT and Orbscan]Ⅱ have large differences.

Comparison of Anterior Segment Measurements Using Scanning-Slit Topography and Optical Low-Coherence Reflectometry (OLCR) Biometry

PURPOSE: To compare the results of anterior segment biometry including white-to-white (WTW) between scanning-slit topography (ORBscan IIz(R), Bausch & Lomb), optical low-coherence reflectometry (OLCR) biometry (Lenstar(R), Haag-Streit), and Castroviejo calipers. METHODS: Measurements on 72 eyes of 36 patients that underwent refractive surgery were measured using ORBscan(R), Lenstar(R), and calipers and compared. Ocular biometry parameters used in this study included the WTW, central corneal thickness, anterior chamber depth (ACD), keratometry, and pupil size. RESULTS: The WTW measurements using ORBscan(R) and calipers (11.57 +/- 0.35 mm and 11.58 +/- 0.34 mm, respectively) were statistically similar. However, the measurement using Lenstar(R) (12.05 +/- 0.40 mm) was significantly greater than with the other methods (p < 0.001). Central corneal thickness and keratometry measurements using ORBscan(R) were greater than when using Lenstar(R) (p = 0.01 for both). ACD and pupil size measurement using Lenstar(R) were greater than when using ORBscan(R) (p < 0.001 for both). CONCLUSIONS: Because WTW and ACD measurements using Lenstar(R) were greater than when using ORBscan(R) and calipers, unexpected high-vaulting may be observed due to the selection of a larger-sized posterior chamber phakic intraocular lens. Therefore, the differences in measurements obtained when using these methods should be considered.

Comparison of Anterior Segment Measurements Using Scanning-Slit Topography and Optical Low-Coherence Reflectometry (OLCR) Biometry

PURPOSE: To compare the results of anterior segment biometry including white-to-white (WTW) between scanning-slit topography (ORBscan IIz(R), Bausch & Lomb), optical low-coherence reflectometry (OLCR) biometry (Lenstar(R), Haag-Streit), and Castroviejo calipers. METHODS: Measurements on 72 eyes of 36 patients that underwent refractive surgery were measured using ORBscan(R), Lenstar(R), and calipers and compared. Ocular biometry parameters used in this study included the WTW, central corneal thickness, anterior chamber depth (ACD), keratometry, and pupil size. RESULTS: The WTW measurements using ORBscan(R) and calipers (11.57 +/- 0.35 mm and 11.58 +/- 0.34 mm, respectively) were statistically similar. However, the measurement using Lenstar(R) (12.05 +/- 0.40 mm) was significantly greater than with the other methods (p < 0.001). Central corneal thickness and keratometry measurements using ORBscan(R) were greater than when using Lenstar(R) (p = 0.01 for both). ACD and pupil size measurement using Lenstar(R) were greater than when using ORBscan(R) (p < 0.001 for both). CONCLUSIONS: Because WTW and ACD measurements using Lenstar(R) were greater than when using ORBscan(R) and calipers, unexpected high-vaulting may be observed due to the selection of a larger-sized posterior chamber phakic intraocular lens. Therefore, the differences in measurements obtained when using these methods should be considered.

Effect of Orthokeratologic Lenses on Myopic Progression in Childhood

PURPOSE: The present study assessed the influence of overnight orthokeratology (ortho-k) on the myopic progression in Korean children and analyzed factors affecting myopic progression. METHODS: The ortho-k group was comprised of 31 patients satisfying the inclusion criteria for ortho-k. In the ortho-k group, spherical equivalent refractive error (SER) was measured at baseline, and after 2 weeks, 6 and 12 months. The control group was comprised of 31 patients who were matched according to age, gender, and baseline SER of the ortho-k subjects. RESULTS: In the ortho-k group, the mean +/- SD changes in SER from 2 weeks to 6 months, 6 to 12 months, and 2 weeks to 12 months were -0.17 +/- 0.50 D, -0.04 +/- 0.76 D, and -0.21 +/- 0.78 D, respectively. In the control group, the changes in SER from baseline to 6 months, 6 to 12 months, and baseline to 12 months were -0.38 +/- 0.42 D, -0.44 +/- 0.38 D, and -0.82 +/- 0.68 D, respectively. Significant differences were found between changes in SER from 6 to 12 months and from baseline to 12 months (p or = -0.5 D with the group of SER change < -0.5 D, numeric values of white-to-white diameters of the 2 groups were different, and a significant correlation was found between the range of SER change and the white-to-white diameter (Pearson's r = -0.471, p = 0.008). CONCLUSIONS: Ortho-k is effective for slowing myopic progression. The smaller the white-to-white diameter, the slower the myopic progression could be.

Comparison of White-to-White Diameters Measured by IOLMaster, Lenstar, Orbscan, and a Manual Method

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

Effect of Preoperative Crystalline Lens Rise on Vaulting after Implantable Collamer Lens Implantation

PURPOSE: To evaluate the parameters affecting vaulting and correlation between preoperative crystalline lens rise and vaulting after implantable collamer lense (ICL) implantation. METHODS: A total of 53 eyes of 34 patients who underwent ICL implantation were examined retrospectively. White-to-white (WTW) and anterior chamber depth (ACD) were obtained from scanning topography (ORB scan) before surgery. Preoperative crystalline lens rise (CLR) and vaulting at 6 months after ICL implantation were measured using anterior segment optic coherence tomography (AS-OCT). Multiple regression analysis was performed to evaluate the factors affecting central vaulting. RESULTS: The mean preoperative crystalline lens rise was -120 +/- 219 microm, and mean central vaulting 6 months after surgery was 544 +/- 175 microm. Preoperative SE, WTW, ACD, and CLR were significantly correlated with vaulting at 6 months after surgery. With the use of meaningful variables, multiple regression analysis showed that CLR, WTW, ACD and SE, in that order of influence, had significant effects on vaulting and the multiple regression equation was obtained as follows: Vaulting (microm) = (160.913 x ACD (mm)) + (170.134 x WTW (mm)) + (-0.338 x CLR (microm)) + (-23.783 x SE (D)) - 2250.184. CONCLUSIONS: CLR had a stronger influence on vaulting after ICL implantation than the previously proven parameters: WTW, ACD, and SE. In addition to WTW, ACD and SE, CLR should also be considered a new criterion for estimating vaulting after ICL implantation.

Comparison of Eyemetrics and Orbscan automated method to determine horizontal corneal diameter.

Purpose: To compare horizontal corneal diameter measurements using the Orbscan Eyemetrics function and Orbscan corneal topographer. Materials and Methods: Seventy-three eyes of 37 patients were included in the study. In all cases, the automated white-to-white (WTW) measurements were obtained using Orbscan by two observers. Using the Eyemetrics function, the WTW was measured manually by the same observers from limbus to limbus using the digital caliper passing through the five point corneal reflections on the Orbscan real image. The data was analyzed using SPSS software for correlation, reliability and inter-rater repeatability. Results: The mean horizontal corneal diameter was 11.74 ± 0.32mm (SD) with the Orbscan and 11.92 ± 0.33mm (SD) with Eyemetrics Software-based measurement. A good positive correlation (Spearman r = 0.720, P = 0.026) was found between these two measurements. The coefficient of inter-rater repeatability was 0.89 for the Orbscan and 0.94 for the Eyemetrics software measurements on the anterior segment images. The Bland and Altman analysis showed large limits of agreement between Orbscan WTW and Eyemetrics WTW measurements. The intra-session repeatability scores for repeat measurements for the Orbscan WTW and Eyemetrics measurements were good. Conclusion: Eyemetrics can be used to measure WTW and the Eyemetrics measured WTW was longer than the WTW measured by Orbscan.

Measurement of White-to-White Diameter and Anterior Chamber Depth by Dual Scheimpflug Camera

PURPOSE: To estimate the horizontal and vertical white-to-white diameters (WTW) and anterior chamber depths (ACD) with a dual Scheimpflug camera (GALILEI(TM), Ziemer, Switzerland) and to compare the estimates measured by a measuring caliper and ultrasound biomicroscopy (UBM PlusTM, Paradigm Inc., Utah, USA) in normal subjects. METHODS: Forty-four eyes of 23 subjects were evaluated. Corneal diameter as measured by GALILEI was directly compared with the white-to-white diameter (WTW) measured by a caliper and the correlation with ciliary sulcus diameter (STS) by UBM was evaluated. The anterior chamber depth (ACD) as measured by GALILEI(TM) was compared with the estimates measured by UBM. RESULTS: The horizontal and vertical diameters of WTW by GALILEI were not significantly different from the measurements taken by calipers (p>0.05, p>0.05, respectively), and there were no correlations between the measurements (r=-0.074, p>0.05 at 180degrees r=0.297, p>0.05 at 90degrees, respectively). The estimates by GALILEI did not correlate with those measured with UBM (r=-0.006, p>0.05 at 180degrees r=-0.222, p>0.05 at 90degrees, respectively). However, the mean ACD by GALILEI was deeper than thatby UBM (p<0.01), and the measurements correlated strongly with each other (r=0.760; p<0.01). CONCLUSIONS: The mean WTW measured by GALILEI was not significantly different from the measurements taken by calipers and the measurements did not correlate with each other. There was also no correlation with the measurementsby GALILEI and UBM. ACD by GALILEI was measured to be deeper those that by UBM.