Effect of Myopia Severity on the Health-Related Quality of Life in Children and Their Parents.

PURPOSE: To investigate the effect of different myopia severity on the health-related quality of life (QOL) in both children and their parents. METHODS: Cross-sectional study from October to November, 2021. Age and sex-matched children with binocular emmetropia (-0.5D < spherical equivalence [SE] < 0.5D), low myopia (-5.0D < SE ≤ -0.5D), and high myopia (SE ≤ -5.0D), as well as their parents, were enrolled. All children underwent ocular examinations. The Pediatric Quality of Life Inventory (PedsQL) Generic Core Scales, Version 4 (child-report, 23 items) and the PedsQL Family Impact Module, Version 2 (parent-report, 36 items) was used for QOL assessment of the children and their parents, respectively. RESULTS: Forty-one, 48 and 45 age- and sex-matched children with their accompanying parents were included in the emmetropia, low myopia and high myopia group, respectively. Parents in the three groups also did not differ in age, sex, or education level. The median total QOL scores were comparable for emmetropic and low myopic children (96.74 [IQR: 93.48-97.83] vs. 96.74 [IQR: 94.57-98.37]) but were significantly lower for high myopic children (88.04 [IQR: 82.61-92.39], both p < .001). A decreasing trend was observed in the median total QOL for parents in the emmetropia (96.53, IQR: 86.81-100), low myopia (82.30, IQR: 70.83-97.22), and high myopia group (70.83, IQR: 60.42-84.03) (p for trend <.001). The effect of per myopic diopter change on QOL was larger in parents than children (coefficient: 1.48 (95%CI: 1.19-1.78) vs. 2.58 [95%CI: 1.83-3.32]), and parents with higher educational level appeared to have more reduction in QOL (p = .008). CONCLUSIONS: More severe myopia resulted in a larger QOL decrease in both children and parents. Significantly reduced QOL were identified in children with high myopia and parents of children with any myopia.

Distribution and associated factors of crystalline lens volume in noncataract adolescents and adults and patients with cataract in a Chinese population.

PURPOSE: To explore the distribution of lens volume (VOL) and its associated factors in noncataract adolescents and adults and patients with cataract in a Chinese population. SETTING: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. DESIGN: Cross-sectional study. METHODS: 1674 eyes from 1674 Chinese participants (690 adolescents and 363 adults without cataract, and 621 patients with cataract) aged from 7 to 90 years were included. Lens thickness (LT) and lens diameter (LD) were measured using swept-source anterior segment optical coherence tomography (SS-AS OCT) to calculate VOL. Axial length (AL) was measured by IOL-Master 700. Pearson correlation analysis and multivariate linear regression models were used to evaluate the potential associated factors of lens dimensions. RESULTS: The mean VOL was 167.74 ± 12.18 mm 3 in noncataract adolescents, 185.20 ± 14.95 mm 3 in noncataract adults, and 226.10 ± 49.25 mm 3 in patients with cataract. VOL had no significant correlation with AL in patients with cataract ( P > .05), neither in noncataract adolescents nor noncataract adults, when adjusted with LT, LD, age, and sex ( P > .05). On the other hand, eyes with longer ALs tended to have smaller LTs and larger LDs in all groups (all P -trend < .05). Larger VOL was associated with older age in all groups (all P < .001). CONCLUSIONS: A data set of VOLs in Chinese eyes over a wide age range was presented. It is inaccurate to predict VOL, LT, and LD solely according to AL. The direct measurement and calculation of VOL in vivo and the establishment of the normal range of VOL could help predict the size of lens capsular bag and plan cataract surgery.

Building prediction models of clinically significant intraocular lens tilt and decentration for age-related cataract.

PURPOSE: To explore the risk factors and construct nomogram models to predict the risks of clinically significant intraocular lens (IOL) tilt and decentration after cataract surgery in patients with age-related cataract. SETTING: Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN: Prospective cohort study. METHODS: 207 patients (207 eyes) who underwent phacoemulsification combined with IOL implantation were enrolled in the study. Casia2 was used to measure the tilt and decentration of crystalline lenses and IOLs before and 3 months after surgery. Univariate and multivariate logistic regression analyses were used to determine the risk factors of clinically significant IOL tilt and decentration, and nomogram prediction models were constructed according to the results of the multivariate logistic regression analysis. RESULTS: Two hundred and seven patients were included in analysis. 24 eyes (11.59%) and 16 eyes (7.73%) had clinically significant IOL tilt and decentration at 3 months after cataract surgery. Multivariate logistic regression analysis revealed that preoperative crystalline lens tilt and decentration were the risk factors for clinically significant IOL tilt (odds ratio [OR], 3.519, P < .001) and decentration (OR, 410.22, P = .001), respectively. Axial length was another association factor for clinically significant IOL decentration (OR, 2.155, P = .019). The risk models demonstrated good calibrations and discriminations for the predictions of clinically significant IOL tilt (receiver operating characteristic [ROC] area = 0.833, cutoff value = 6.5) and decentration (ROC area = 0.757, cutoff value = 0.08). CONCLUSIONS: The good performances of our models suggested that they may be useful risk prediction tools for postoperative IOL tilt and decentration. The measurement of preoperative crystalline lens tilt and decentration should be one of the routine examinations before cataract surgery, especially for toric and multifocal IOLs.

In-vivo Lens Biometry Using the Novel Ultrasound Biomicroscopy.

BACKGROUND AND AIM: To assess the reproducibility of the novel ultrasound biomicroscopy, Insight 100 and its agreement with a swept-source optical coherence tomography, CASIA2. METHODS: A total of 96 volunteers (96 eyes) were enrolled. The radius of anterior lens curvature (RAL), the radius of posterior lens curvature (RPL), lens thickness (LT), and lens diameter (LD) were measured with Insight 100 and CASIA2. A semiautomated software was used to adjust the measurement of LT (LTS) and LD (LDS) by Insight 100. Intraobserver and interobserver reproducibility of Insight 100 measurements, and the agreement of results from Insight 100 and CASIA2 were assessed with 95% limit of agreement (LoA), intraclass correlation coefficient (ICC), Pearson correlation, and linear regression. RESULTS: For Insight 100 measurements, the intraobserver ICCs of RAL, RPL, LTS, and LDS measurement were 0.996, 0.973, 0.936, and 0.889, and the interobserver ICCs were 0.987, 0.890, 0.974, and 0.816, respectively. There was an excellent correlation in LT measurements (R = 0.961, P < 0.001) but poor agreements in other parameters between the two devices. The LD measurements tended to be larger (95% CI: 0.768-0.928) in CASIA2 when compared with Insight 100. CONCLUSION: Insight 100 could obtain highly repeatable lens biometry in vivo. With better signal penetration, it shows promising potential in future clinical applications.

Agreement of Anterior Segment Parameter Measurements With CASIA 2 and IOLMaster 700.

PURPOSE: To compare the difference and agreement in central corneal thickness (CCT), keratometry (K), anterior chamber depth (ACD), aqueous depth (AQD), and lens thickness (LT) measured with CASIA 2 and IOLMaster 700 in patients with cataract. METHODS: A total of 81 patients with cataract (81 eyes) scheduled for phacoemulsification were prospectively collected from March to May, 2020 in the cataract department of Zhongshan Ophthalmic Center, Sun Yat-sen University, including 43 males and 38 females with age of 61.5 ± 10.6 years. CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT were measured with CASIA 2 and IOLMaster 700. Paired t-test, intraclass correlation coefficients (ICCs), 95% limit of agreement (95% LoA), and Bland-Altman plots were performed and used to analyze the difference and agreement between the two devices. RESULTS: There was no statistically significant difference in anterior K measurement with the CASIA 2 (44.3 ± 1.66 mm) and IOLMaster 700 (44.31 ± 1.67 mm, P = 0.483). Differences among the CCT, anterior Kf, real Kf, real Ks, ACD, AQD, and LT measured by the two instruments were statistically significant (P < 0.001). The ICCs of CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT measurements between the two devices were 0.892, 0.991, 0.991, 0.827, 0.817, 0.937, 0.926, and 0.997, respectively. The 95% LoA between CASIA 2 and IOLMaster 700 was -30.06 to 0.43 µm for CCT, -0.3 to 0.48 D for anterior Kf, -0.46 to -0.43 D for anterior Ks, -1.49 to -0.49 D for real Kf, -1.62 to -0.49 D for Real Ks, -0.03 to 0.24 mm for ACD, 0.04 to 0.25 mm for AQD, and -0.06 to 0.09 mm for LT. CONCLUSION: Anterior Kf, anterior Ks, ACD, AQD, and LT have excellent agreement between the two devices. CCT, real Kf, and real Ks have moderate agreement between the two devices. It is recommended to use anterior Kf, anterior Ks, ACD, AQD, and LT interchangeably between CASIA 2 and IOLMaster 700.

Accuracy of Intraocular Lens Calculation Formulas in Patients Undergoing Combined Phakic Intraocular Lens Removal and Cataract Surgery.

PURPOSE: To investigate the prediction accuracy of intraocular lens (IOL) calculation formulas, and the impact of anterior chamber depth (ACD) and lens thickness (LT) measurement errors on IOL power calculation in patients undergoing combined phakic IOL (PIOL) removal and cataract surgery. DESIGN: Retrospective, consecutive case series study. METHODS: Thirty-six PIOL implanted eyes (12 anterior chamber PIOLs and 24 posterior chamber PIOLs [PC-PIOL]) undergoing cataract surgery were included. The prediction accuracy of new formulas (Barrett universal II, Emmetropia verifying optical, Kane, and Ladas super formula) and traditional formulas (Haigis, Hoffer Q, Holladay 1 and SRK/T) with or without Wang-Koch (WK) axial length (AL) adjustment was evaluated. The influence of ACD and LT measurement errors of IOLMaster 700 on refractive outcomes was also investigated. RESULTS: The Kane and traditional formulas with WK AL adjustment had no significant systematic prediction error and displayed a smaller median absolute error, whereas the other formulas showed significant hyperopia shift (P < .05) and relatively lower prediction accuracy. The accuracy rate of IOLMaster 700 in measuring the ACD and LT was 100% in eyes with anterior chamber PIOL implantation, and 37.50% in the PC-PIOL subgroup. No significant difference was observed in refractive outcomes of formulas using correct and wrong parameters in the PC-PIOL subgroup (P > .05). CONCLUSIONS: The Kane and traditional formulas with WK AL adjustment exhibited relatively higher prediction accuracy in patients who underwent combined PIOL removal and cataract surgery. The IOLMaster 700 displayed low accuracy in ACD and LT measurements for PC-PIOL implanted eyes, but showed negligible impact on IOL prediction accuracy.

Objective quantification of lens nuclear opacities using swept-source anterior segment optical coherence tomography.

BACKGROUND/AIMS: The primary objective is to quantify the lens nuclear opacity using swept-source anterior segment optical coherence tomography (SS-ASOCT) and to evaluate its correlations with Lens Opacities Classification System III (LOCS-III) system and surgical parameters. The secondary objective is to assess the diagnostic performance for hard nuclear cataract. METHODS: This cross-sectional study included 1222 patients eligible for cataract surgery (1222 eyes). The latest SS-ASOCT (CASIA-2) was used to obtain high-resolution lens images, and the average nuclear density (AND) and maximum nuclear density (MND) were measured by a custom ImageJ software. Spearman's correlations analysis was used to assess associations of AND/MND with LOCS-III nuclear scores, visual acuity and surgical parameters. The subjects were then split randomly (9:1) into the training dataset and validating dataset. Receiver operating characteristic curves and calibration curves were constructed for the classification on hard nuclear cataract. RESULTS: The AND and MND from SS-ASOCT images were significantly correlated with nuclear colour scores (AND: r=0.716; MND: r=0.660; p<0.001) and nuclear opalescence scores (AND: r=0.712; MND: r=0.655; p<0.001). The AND by SS-ASOCT images had the highest values of Spearman's r for preoperative corrected distance visual acuity (r=0.3131), total ultrasonic time (r=0.3481) and cumulative dissipated energy (r=0.4265). The nuclear density had good performance in classifying hard nuclear cataract, with area under the curves of 0.859 (0.831-0.886) for AND and 0.796 (0.768-0.823) for MND. CONCLUSION: Objective and quantitative evaluation of the lens nuclear density using SS-ASOCT images enable accurate diagnosis of hard nuclear cataract.

Clinically Significant Intraocular Lens Decentration and Tilt in Highly Myopic Eyes: A Swept-Source Optical Coherence Tomography Study.

PURPOSE: To investigate the occurrence and risk factors of clinically significant intraocular lens (IOL) decentration and tilt in highly myopic eyes using swept-source anterior segment optical coherence tomography (SS-AS-OCT). DESIGN: Cross-sectional study. METHODS: This study included 334 participants (334 eyes) with high myopia, defined as axial length (AL) ≥26 mm, who underwent phacoemulsification with IOL implantation. Decentration and tilt of IOL were assessed by SS-AS-OCT. Clinically significant IOL decentration and tilt was defined as decentration ≥0.4 mm and tilt ≥7°. Routine preoperative and postoperative examinations included visual acuity, refraction, biometric measurement using IOLMaster 700 (Carl Zeiss Meditec), and objective visual quality evaluated by OPD-Scan III (Nidek Technologies). RESULTS: Among the 334 highly myopic participants, 71 (21.3%) had clinically significant IOL decentration, and 26 (7.78%) had clinically significant IOL tilt. The proportion of clinically significant IOL decentration (37.1% vs 14.0%, P < .001) and tilt (16.2% vs 3.90%, P < .001) in those with AL ≥30 mm was significantly higher than in those with AL <30 mm. The multivariable logistic regression model showed only AL ≥30 mm was associated with clinically significant IOL decentration (odds ratio, 1.65; P = .002). AL ≥30 mm (odds ratio, 2.09; P = .001) was an independent risk factor for clinically significant IOL tilt after adjusting for confounders. AL ≥30.3 mm could effectively predict IOL decentration ≥0.6 mm (area under the curve, 0.802). CONCLUSIONS: Participants with AL >30 mm have a higher risk of clinically significant IOL decentration and tilt, thus caution should be taken to implant multifocal or toric IOL for these patients.

Effect of High Myopia on Dynamic Changes of Anterior Angle After Pharmacologic Mydriasis in Cataract Patients: A SS-ASOCT Study.

Purpose: The purpose of this study was to evaluate the effect of high myopia on anterior angle change after pharmacologic mydriasis in patients with cataract using swept-source anterior segment optical coherence tomography (SS-ASOCT). Methods: This prospective cross-sectional study continuously recruited patients with cataract aged 40 years and older during the period August 2019 to August 2020. The anterior segment parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular-iris angle (TIA), angle to angle width (ATA), and anterior chamber volume (ACV), were obtained using SS-ASOCT at baseline and 30 minutes after mydriasis. Regression analyses were performed to identify the factors related to the relative change of AOD500 (ΔAOD500). Results: A total of 938 patients (938 eyes) were included. The AOD500 decreased from 0.46 ± 0.22 mm to 0.40 ± 0.19 mm, with percent ΔAOD500 of -13.59% ± 37.73% (P = 0.005). The patients with high myopia had a smaller reduction of anterior angle parameters, with a percent ΔAOD500 of -22.74% ± 58.09%% in non-high myopic eyes and -0.84% ± 45.47% in high myopic eyes (P < 0.001). The stepwise multivariate regression demonstrated that the smaller reduction of AOD500 were independently associated with younger age (coefficient = -2.11, 95% confidence interval [CI] = -2.59 to -1.64, P < 0.001), presence of high myopia (coefficient = 15.35, 95% CI = 3.63 to 27.07, P = 0.010), greater baseline TISA500 (coefficient = 60.78, 95% CI = 8.75 to 112.82, P = 0.022), and ATA (coefficient = 11.21, 95% CI = 4.53 to 17.89, P = 0.001). Conclusions: The anterior chamber angle decreased after pharmacologic mydriasis in these patients with cataract. Angle shallowing after pharmacologic mydriasis was significantly less pronounced in high myopic eyes than in non-high myopic eyes. Translational Relevance: These findings are informative for the relative less risk of angle-closure glaucoma in highly myopic eyes.

The Structure of the Lens and Its Associations with the Visual Quality.

In humans, the lens is the organ with the ability to change morphology and refractive power, designated as accommodation, to focus light from various distances and obtain clear retinal image. The accommodative ability of the lens depends on its structure and biological parameters. The lens grows throughout the life, forming specific lens sutures and a unique gradient refractive index, and possesses regenerative ability under certain circumstances. Minimally invasive lens surgery that preserves endogenous lens epithelial stem/progenitor cells (LECs) can achieve functional lens regeneration in humans. The lens is the main source of intraocular aberration, especially intraocular higher-order aberrations (IHOAs) which is found to be binocularly symmetrical in phakic eyes. There is a compensation mechanism between corneal aberrations and lens aberrations. Therefore, the structure and the biological parameters of the lens, the binocular relationship of the lens and the correlation between the lens and cornea affect visual quality. This paper summarises the above findings and their current and potential applications in refractive surgeries, providing a comprehensive understanding of the lens as a strong determinant of visual quality in the optical system.

Determinants of intraocular lens tilt and decentration after cataract surgery.

BACKGROUND: To identify the main determinants of intraocular lens (IOL) tilt and decentration after cataract surgery using a novel anterior segment optical coherence tomography (AS-OCT) method. METHODS: Fifty-six patients who underwent phacoemulsification with IOL implantation in one eye were continuously enrolled in this cohort study. Axial length (AL) was measured with IOL Master 700. The tilt and decentration of patients' preoperative crystalline lenses and postoperative IOLs, as well as crystalline lens thickness (LT), were measured using AS-OCT before surgery and 1 week after surgery. RESULTS: The mean tilt and decentration of the patients' preoperative crystalline lenses were 4.90°±1.81° and 0.21±0.02 mm, and the mean tilt and decentration of IOLs were 4.75°±1.66° and 0.21±0.02 mm, respectively. There were no significant differences in magnitude, direction of tilt, or decentration between crystalline lenses and IOLs. The strongest determinant of IOL tilt was preoperative crystalline lens tilt (R2=0.512, P<0.001), followed by AL (R2=0.154, P=0.003). Additionally, crystalline lens decentration and AL explained 54.6% of the variability in IOL decentration. AL was the factor most highly associated with IOL decentration (R2=0.332, P<0.001), rather than crystalline lens decentration (R2=0.214, P<0.001). CONCLUSIONS: The position of the preoperative crystalline lens and AL were the critical determinants of IOL tilt and decentration. The tilt and decentration of IOLs will be greater in patients with larger tilt and decentration of crystalline lenses, or shorter and longer AL.

Profiles of intraocular higher-order aberrations in healthy phakic eyes: prospective cross-sectional study.

BACKGROUND: Ocular wavefront aberration is a crucial optical factor affecting retinal imaging. Internal aberrations contributed to compensation mechanism of ocular aberration. However, previous studies mainly focused on total and corneal higher order aberrations, and little is known about the profile of internal HOA (IHOA) in healthy subjects. METHODS: Participants with healthy crystalline lenses were prospective enrolled. The root mean square (RMS) of IHOAs for a pupil diameter of 4 mm were measured with an iTrace aberrometer. Lenticular parameters were measured with a swept source anterior segment optical coherence tomography (AS-OCT). Regression analyses were used to determine factors associated with logarithmic IHOAs. RESULTS: Sixty-six Chinese participants (132 eyes) ranging from 5 to 59 years were analyzed. Logarithmic IHOA was positively associated with axial length (AL) (coefficient =0.101, P=0.016), and negatively associated with ocular refraction (coefficient =-0.032, P=0.023). Logarithmic internal coma increased by 0.161/mm (P=0.016) as AL became longer and decreased by 0.081/diopter (P<0.001) as ocular refraction became hyperopic. Lens tilt (coefficient =-0.121, P=0.037), decentration (coefficient= 3.027, P=0.003), and radius of anterior lens surface curvature (RAL) (coefficient= 0.096, P=0.026) were associated with logarithmic internal trefoil. lens tilt was also associated with logarithmic internal spherical aberration (coefficient =-0.195, P=0.018) and second astigmatism (coefficient =-0.132, P=0.030). Binocularly, the extent of coma, trefoil was different, while that of spherical aberration, secondary astigmatism was consistent. The vectors of the same type of IHOAs were nearly paralleled. CONCLUSIONS: IHOAs are mainly affected by ocular refraction, RAL, lens tilt and decentration. Intraocular differences and directions of higher-order aberrations follow certain rules, and their effects on visual function warrant further study.

Fluid-jet technique to polish the posterior capsule for phacoemulsification surgeries: efficacy and safety evaluation.

PURPOSE: To compare the efficacy and safety of a fluid-jet technique with capsular polish in reducing residual lens fibers (RLFs) in phacoemulsification surgery. SETTING: Single center. DESIGN: Prospective nonrandomized comparative study. METHODS: Patients receiving phacoemulsification were included. Consecutive eligible patients alternately underwent either removal of RLFs on the posterior capsule using capsular polish after irrigation and aspiration, and before intraocular lens (IOL) implantation, or RLF removal using a fluid-jet technique after IOL implantation. Posterior capsular images were used to quantify RLFs. Visual parameters were evaluated at 1 day, 1 week, and 1 year postoperatively. The proportion of capsule occupied by posterior capsule opacification (PCO) (area %) and incidence of protocol-driven laser posterior capsulotomy were recorded at 1 year in masked fashion. RESULTS: Seven hundred forty eyes were allocated to polishing (n = 370) or fluid-jet technique (n = 370). Polishing required 70.4 ± 17.5 seconds and fluid-jet 32.2 ± 9.9 seconds (P ≤ 0.001). Compared with the polishing group, capsular area occupied by RLFs in the fluid-jet group was significantly smaller (3.5% vs 0.5%, P = .031) at the end of surgery. One day postoperatively, the fluid-jet group had more desirable corrected distance visual acuity, objective scattering index, and Strehl ratio (all P < .05). PCO area percentage did not differ between groups (6.5% vs 4.5%, P = .252) 1 year postoperatively, but incidence of posterior capsulotomy was lower in the fluid-jet group (3.2% vs 0.8%, P = .019). CONCLUSIONS: Fluid-jet removed RLFs effectively and had lower incidence of postoperative capsulotomy than capsular polishing.

Characteristics and factors associated with intraocular lens tilt and decentration after cataract surgery.

PURPOSE: To analyze the characteristics and factors associated with intraocular lens (IOL) tilt and decentration after uneventful phacoemulsification with IOL implantation. SETTING: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. DESIGN: Cross-sectional study. METHODS: All patients underwent a general ophthalmologic examination and anterior segment photography. IOL tilt and decentration were measured with a second-generation anterior segment optical coherence tomography (Casia2). Univariate and multivariate regression analyses were performed to assess the association between IOL tilt and decentration with ocular biometric and systemic parameters, and the visual acuity. RESULTS: A total of 196 eyes of 196 patients were enrolled in this study. IOLs showed a mean tilt of 4.8 degrees toward the inferotemporal direction, and the mean decentration was 0.21 mm. Both eyes presented a mirror symmetry relationship. Twenty-two eyes (11.22%) had a tilt greater than 7 degrees, and 21 eyes (10.72%) had a decentration more than 0.4 mm. Multivariate regression analysis showed previous pars plana vitrectomy (PPV) and short axial length (AL) were associated with greater IOL tilt (P = .014 and P < .001). In addition, long AL, thicker lens, and less capsulorhexis-IOL overlap were positively correlated with decentration (P < .001, P = .029, and P = .026). Corrected distance visual acuity did not directly correlate with IOL tilt and decentration (P = .417 and P = .550). CONCLUSIONS: PPV history and short AL were associated with greater IOL tilt, whereas longer AL, thicker lens, and overlarge capsulorhexis contribute to greater decentration. Implantation of toric and multifocal IOLs in these patients should be cautious.

Comparison of radius of anterior lens surface curvature measurements in vivo using the anterior segment optical coherence tomography and Scheimpflug imaging.

BACKGROUND: To assess the radius of anterior lens surface curvature (RAL) measurements with anterior segment optical coherence tomography (AS-OCT) in comparison with Scheimpflug imaging. METHODS: This prospective, cross-sectional study was carried out at Zhongshan Ophthalmic Center, Guangzhou, China. We enrolled 59 eyes, including 30 eyes from 30 cataractous volunteers (59 to 87 years) and 29 eyes from 29 young participants (19 to 49 years). After mydriasis, the RAL was measured automatically by the built-in software in the AS-OCT (CASIA 2). The Scheimpflug images were measured with the build-in caliper tool of the Scheimpflug camera (Pentacam), and RAL were further calculated with the principle of best-fitted circle. Intraobserver and interobserver reproducibility of RAL measurement using Scheimpflug camera were evaluated with limit of agreement (LoA) and intraclass correlation coefficient (ICC). Consistency between RAL measurement of Scheimpflug camera and AS-OCT were assessed with LoA, correlation analysis and linear regression. RESULTS: For all subjects, intraobserver (LoA: -0.25 to 0.23 mm, ICC: 0.996) and interobserver reproducibility (LoA: -0.85 to 0.92 mm, ICC: 0.947) of RAL were good using Scheimpflug imaging. Both AS-OCT and Scheimpflug imaging found that the age-related cataract participants had smaller RAL (P=0.010, P=0.001 respectively). LoA of RAL measurement between AS-OCT and Scheimpflug imaging was -3.83 to -0.79 mm, and the Pearson correlation efficient was 0.909 (P<0.001). The RAL values measured by AS-OCT were significantly greater than that by Scheimpflug camera with a mean difference of 2.31 mm for all participants (P<0.001). The RAL measurement could be converted using the equation: YCASIA 2 =1.155 × XPentacam + 1.060. CONCLUSIONS: Both Scheimpflug camera system with internal caliper tool and the AS-OCT are fast and non-contact tools that could measure RAL successfully. The two measurement results are highly correlated and interchangeable through linear regression equation.

Effect of Axial Length Adjustment Methods on Intraocular Lens Power Calculation in Highly Myopic Eyes.

PURPOSE: To evaluate the performance of Holladay 1 and SRK/T formulas with the axial length (AL) adjustment methods including the linear and nonlinear versions of Wang-Koch AL adjustment methods and Cooke-modified AL (CMAL); and to determine whether the CMAL should be extended to the latest Barrett Universal II, Ladas Super formula (LSF), and Emmetropia Verifying Optical formulas in highly myopic eyes. DESIGN: Retrospective, consecutive case-series study. METHODS: A total of 164 eyes of 164 patients with AL ≥26.0 mm were included and divided into 2 groups: AL <28.0 mm (Group 1) and AL ≥28.0 mm (Group 2). The average arithmetic spherical equivalent prediction error (PE), mean absolute PE, median absolute error (MedAE), and the percentage of eyes within ±0.25 diopter (D), ±0.50 D, and ±1.0 D of PE were determined. RESULTS: The Holladay 1 formulas showed the smallest MedAE when combined with the first linear or nonlinear version of Wang-Koch AL adjustment methods, both in total and in subgroups. The SRK/T formula displayed the highest prediction accuracy in combination with the first linear version of Wang-Koch adjustment method in total and subgroups. The CMAL reduced the absolute PE of LSF in total (P = .003) and in Group 1 (P = .017). CONCLUSIONS: The Holladay 1 and SRK/T formulas combined with specific AL adjustment methods had accuracy similar to the fourth-generation formulas for highly myopic eyes. Moreover, the CMAL can improve the accuracy of the LSF for highly myopic eyes.