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Background: To determine the interchangeability of Scansys (MediWorks, Shanghai, China) and entacam HR (Oculus, Wetzlar, Germany) in anterior segment measurements. Research designs and methods: 42Forty-two healthy individuals' right eye (mean age 31.5 ± 7.3 years) were assessed for keratometry (K), central corneal thickness (CCT), thinnest corneal thickness (TCT), pupil center pachymetry, corneal volume, anterior chamber volume (ACV), anterior chamber depth (ACD), terior chamber angle (ACA), intraocular pressure (IOP) sum, Q-value (asphericity), and horizontal white-to-white (WTW). Intraclass correlation coefficient (ICC), linear regression analysis, difference of mean, and Bland-Altman plots [bias line and 95% limits of agreement (LoA)] were analyzed. Results: Scansys repeated excellently the Pentacam HR for keratometry (except for anterior steep K), ACD, pupil center pachymetry, CCT, TCT, IOP sum, and corneal volume (all ICC > 0.9, r2 > 0.8, and narrow LoAs). There was strong correlations in measuring WTW and ACV (r2 = 0.631 and r2 = 0.623, respectively) and weak correlations in measuring ACA and Q values (all r2 < 0.5). Conclusion: The interchangeability of devices were confirmed in measuring ACD, pupil center achymetry, CCT and TCT, IOP sum, corneal volume, and keratometry except for the anterior steep K. However, in measuring WTW, ACV, asphericity, and ACA, Scansys should not be used instead of Pentacam HR. [ABSTRACT FROM AUTHOR]

Abstract Keratoconus (KC) is an irreversible blinding eye disease; therefore, early screening of KC suspects (KCS) is crucial for protecting patients’ quality of life. Scheimpflug imaging is a commonly used screening device in clinical practice. We aimed to evaluate the diagnostic ability of a Scheimpflug imaging device (Scansys) for KC and KCS and compared it with other Scheimpflug-based devices (Pentacam and Corvis ST). This prospective case-control study included 107 normal eyes, 72 KCS, and 57 KC. Scansys screening index Keratoconus probability (KCP) showed excellent performance in diagnosing KC at a cutoff value of 16.4 (area under the receiver operating characteristic [AUROC] = 1.000), with 100% sensitivity and 98.11% specificity. KCP had a better KCS diagnostic ability at a cutoff value of 8.9 (AUROC = 0.813) than Corvis biomechanical index (CBI, AUROC = 0.764), reaching 67.61% sensitivity and 85.85% specificity. Pentacam screening index Belin/Ambrósio enhanced ectasia display deviation (BAD-D) showed the best performance with 92.96% sensitivity and 89.62% specificity at a cutoff value of 1.525 (AUROC = 0.970) in diagnosing KCS. Scansys provides accurate KCP parameters in diagnosing KC; however, the efficiency of diagnosing KCS should be further optimized.

Abstract Background To analyze the difference and agreement between measurements obtained by a new fully automatic optical biometer, the SW-9000 μm Plus, based on optical low-coherence reflectometry (OLCR) and a commonly used optical biometer (Pentacam AXL) based on Scheimpflug imaging with partial coherence interferometry (PCI). Methods The central corneal thickness (CCT), anterior chamber depth (ACD, from epithelium to anterior lens surface), lens thickness (LT), mean keratometry (Km), corneal astigmatism, corneal diameter (CD), pupil diameter (PD), and axial length (AL) of 74 eyes (from 74 healthy subjects) were measured using the SW-9000 μm Plus and the Pentacam AXL to determine the agreement. Double angle plots were used for astigmatism vector analysis. Bland–Altman and 95% limits of agreement (LoA) were calculated. Results Statistically significant differences were detected for all parameters but J0 vector. The Bland–Altman analysis of AL, CCT, ACD, Km, CD, J0 and J45 indicated a high level of agreement between the two devices. Among AL, CCT, ACD, Km, J0, J45, CD, and PD, the 95% LoA ranged from -0.07 to 0.05 mm, -9.67 to 7.34 mm, -0.11 to 0.04 mm, -0.25 to 0.50 D, -0.22 to 0.20 D, -0.15 to 0.20 D, -0.23 to 0.35 mm and 1.55 to 3.77 mm, respectively. Conclusions The measurements of AL, CCT, ACD, Km, corneal astigmatism, and CD showed a narrow LoA and may be used interchangeably in healthy subjects between the new OLCR optical biometer and the Scheimpflug/PCI biometer; however, a poor agreement was noted for PD values.

Abstract Background Keratoconus in children is often more severe and rapidly progressive compared to adults. While Scheimpflug imaging (Pentacam) improves screening, there are no established pediatric guidelines. Due to challenges in diagnosis, we aimed to correlate clinical factors with abnormal imaging results to aid in the development of screening protocols. Methods A single-center retrospective cohort analysis of patients 3–18 years screened for keratoconus with ophthalmic examination and initial Scheimpflug imaging between 2021 to 2023. Scheimpflug indices including final D, ART max, and calculated CAIRO 8, which is a corneal metric combining pachymetry, ART max, and elevation, were compared to published pediatric ranges for normal and keratoconus corneas. Results Seventy-eight patients (11.8 ± 3.9 years) were screened with the majority referred due to high and/or progressive astigmatism (74 patients, 94%). Forty-nine patients (63%) were male and 48 (62%) self-reported Hispanic ethnicity. Average astigmatism was 4.9 ± 1.8 D and 86% had with-the-rule astigmatism. Fourteen patients (18%) had corneal findings on slit lamp. Average LogMAR CDVA was 0.243 ± 0.274 D. By Pentacam, 55 (70%) patients had ≥ 1 indeterminate or keratoconus value. Patients stratified as keratoconus by all parameters were older (15 vs. 11 years, p = 0.015–0.02), had worse visual acuity (p

Background: To analyze the difference and agreement between measurements obtained by a new fully automatic optical biometer, the SW-9000 μm Plus, based on optical low-coherence reflectometry (OLCR) and a commonly used optical biometer (Pentacam AXL) based on Scheimpflug imaging with partial coherence interferometry (PCI). Methods: The central corneal thickness (CCT), anterior chamber depth (ACD, from epithelium to anterior lens surface), lens thickness (LT), mean keratometry (Km), corneal astigmatism, corneal diameter (CD), pupil diameter (PD), and axial length (AL) of 74 eyes (from 74 healthy subjects) were measured using the SW-9000 μm Plus and the Pentacam AXL to determine the agreement. Double angle plots were used for astigmatism vector analysis. Bland–Altman and 95% limits of agreement (LoA) were calculated. Results: Statistically significant differences were detected for all parameters but J0 vector. The Bland–Altman analysis of AL, CCT, ACD, Km, CD, J0 and J45 indicated a high level of agreement between the two devices. Among AL, CCT, ACD, Km, J0, J45, CD, and PD, the 95% LoA ranged from -0.07 to 0.05 mm, -9.67 to 7.34 mm, -0.11 to 0.04 mm, -0.25 to 0.50 D, -0.22 to 0.20 D, -0.15 to 0.20 D, -0.23 to 0.35 mm and 1.55 to 3.77 mm, respectively. Conclusions: The measurements of AL, CCT, ACD, Km, corneal astigmatism, and CD showed a narrow LoA and may be used interchangeably in healthy subjects between the new OLCR optical biometer and the Scheimpflug/PCI biometer; however, a poor agreement was noted for PD values. [ABSTRACT FROM AUTHOR]

Keratoconus (KC) is an irreversible blinding eye disease; therefore, early screening of KC suspects (KCS) is crucial for protecting patients' quality of life. Scheimpflug imaging is a commonly used screening device in clinical practice. We aimed to evaluate the diagnostic ability of a Scheimpflug imaging device (Scansys) for KC and KCS and compared it with other Scheimpflug-based devices (Pentacam and Corvis ST). This prospective case-control study included 107 normal eyes, 72 KCS, and 57 KC. Scansys screening index Keratoconus probability (KCP) showed excellent performance in diagnosing KC at a cutoff value of 16.4 (area under the receiver operating characteristic [AUROC] = 1.000), with 100% sensitivity and 98.11% specificity. KCP had a better KCS diagnostic ability at a cutoff value of 8.9 (AUROC = 0.813) than Corvis biomechanical index (CBI, AUROC = 0.764), reaching 67.61% sensitivity and 85.85% specificity. Pentacam screening index Belin/Ambrósio enhanced ectasia display deviation (BAD-D) showed the best performance with 92.96% sensitivity and 89.62% specificity at a cutoff value of 1.525 (AUROC = 0.970) in diagnosing KCS. Scansys provides accurate KCP parameters in diagnosing KC; however, the efficiency of diagnosing KCS should be further optimized. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the repeatability of corneal densitometry (CD) measurements obtained using both an anterior-segment optical coherence tomography (AS-OCT) device and a Scheimpflug camera system, while also assessing the level of agreement. The study also sought to investigate the correlation of CD with age, gender, and central corneal thickness (CCT) in normal eyes. Methods: CD measurements were obtained using the Casia 2 and the Pentacam AXL Wave. Data were collected on Total Corneal Densitometry and 4 concentric corneal annular areas, these are referred to as zone 1, denoting the central area, through to zone 4, designating the outermost peripheral region. Repeatability was assessed using intra-session test–retest variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). The agreement was evaluated using Bland–Altman plots. Correlation analysis was performed between CD, age, gender, and CCT. Results: The study included 96 healthy volunteers. The Casia 2 demonstrated high repeatability with ICC values exceeding 0.9 in all the corneal zones and lower CoV values compared to the Pentacam AXL Wave (ranging from 1.07% to 2.25% for Casia 2 and from 1.91% to 6.89% for Pentacam).95% LoA were within ± 2 standard deviation from the average mean except from zone 1 (± 2.42).However, the measurements showed a consistent bias among all the corneal zones. CD values were positively correlated with age, except for zone 1 with the Pentacam (p = 0.083). Conclusions: The findings suggest that the Casia 2 can be a reliable tool for assessing corneal transparency in healthy individuals, however its measurements are not interchangeable with those provided by the Pentacam. The AS-OCT device may be more sensitive in detecting subtle age-related changes in CD within the central zone. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the percent change in central corneal thickness (%ΔCCT) during air-puff-induced deformation as an indicator of corneal biomechanical response. Methods: Forty ex vivo human eyes from forty donors were imaged using the CorVis ST at experimentally controlled intraocular pressure (IOP) of 10, 20, 30, and 40 mmHg, followed by uniaxial strip testing to calculate tensile modulus. The CorVis ST research software tracked the anterior and posterior cornea edges and determined the dynamic corneal response (DCR) parameters. Eyes were excluded if image quality or posterior tracking issues were present. Custom algorithms were used to calculate CCT during deformation using a ray-tracing method to correct for Scheimpflug and optical distortion within each image. Correlation and stepwise regression analyses between the shape-related DCR parameters and %ΔCCT were conducted. A mixed model analysis was performed to test the effect of IOP and the strongest significant predictors of the stepwise regression on %ΔCCT. The significance threshold was set to p < 0.05. Results: Thirty eyes were ultimately analyzed and CCT increased significantly from the pre-deformation state to the highest concavity state at each IOP level (p < 0.001). IOP and multiple shape DCRs were found to be significantly related to %ΔCCT (p < 0.0001). The strongest predictor of %ΔCCT was integrated inverse radius (IIR) (p < 0.0001; partial R2 = 0.4772) with no other parameter having a partial R2 value greater than 0.04. The mixed model analysis showed that IIR was the sole predictor (p = 0.0098) and IOP was no longer significant as a single predictor. However, the interaction of IIR with IOP (p = 0.0023) had a significant effect on %ΔCCT. Conclusion: Percent change in CCT is influenced by corneal stiffness as indicated by the significant relationship with IIR. The %ΔCCT may be a potential biomarker for determining differences in corneal deformation response with corneal diseases. [ABSTRACT FROM AUTHOR]

Abstract Purpose To assess the level of agreement and evaluate the reliability of measurements between two Scheimpflug imaging modalities, Scansys (MediWorks, China) and Sirius (CSO, Italy), in quantifying the anterior segment parameters in healthy eyes. Methods In a cross-sectional study, the right eyes of 38 healthy participants without any ocular or systemic diseases were examined. A range of anterior segment parameters including anterior and posterior flat and steep keratometry, central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), anterior chamber angle (ACA), corneal volume, anterior chamber volume, and horizontal white to white diameter, derived from the sagittal curvature maps were measured. To evaluate the reliability of the measurements, intraclass correlation coefficient (ICC) and correlation coefficient were measured. Additionally, Bland-Altman plots were employed to examine the agreement in mean (bias line) and 95% limits of agreement between the two devices. Results The mean age was 31.5 ± 6.9 (range: 19–47) years. The ICC indicated that the majority of anterior segment parameters had an excellent or good level of reliability, surpassing the threshold of 0.9. Nevertheless, CCT and ACA exhibited a moderate level of reliability, with ICC values of 0.794 and 0.728, respectively. The correlation analysis showed a strong correlation for all the variables tested. The Bland-Altman plots revealed that the bias line was near zero and the 95% limits of agreement were narrow for most variables, except for the anterior flat and steep keratometry, which were found to range from − 0.57 to 0.84 D and − 0.68 to 0.87 D, respectively. Conclusion Scansys and Sirius devices can be effectively used interchangeably for the evaluation of most anterior segment parameters; however, for anterior corneal curvatures, CCT and ACA, their alternative use is not recommended.

Purpose To assess the level of agreement and evaluate the reliability of measurements between two Scheimpflug imaging modalities, Scansys (MediWorks, China) and Sirius (CSO, Italy), in quantifying the anterior segment parameters in healthy eyes. Methods In a cross-sectional study, the right eyes of 38 healthy participants without any ocular or systemic diseases were examined. A range of anterior segment parameters including anterior and posterior flat and steep keratometry, central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), anterior chamber angle (ACA), corneal volume, anterior chamber volume, and horizontal white to white diameter, derived from the sagittal curvature maps were measured. To evaluate the reliability of the measurements, intraclass correlation coefficient (ICC) and correlation coefficient were measured. Additionally, Bland-Altman plots were employed to examine the agreement in mean (bias line) and 95% limits of agreement between the two devices. Results The mean age was 31.5±6.9 (range: 19–47) years. The ICC indicated that the majority of anterior segment parameters had an excellent or good level of reliability, surpassing the threshold of 0.9. Nevertheless, CCT and ACA exhibited a moderate level of reliability, with ICC values of 0.794 and 0.728, respectively. The correlation analysis showed a strong correlation for all the variables tested. The Bland-Altman plots revealed that the bias line was near zero and the 95% limits of agreement were narrow for most variables, except for the anterior flat and steep keratometry, which were found to range from −0.57 to 0.84 D and −0.68 to 0.87 D, respectively. Conclusion Scansys and Sirius devices can be effectively used interchangeably for the evaluation of most anterior segment parameters; however, for anterior corneal curvatures, CCT and ACA, their alternative use is not recommended. [ABSTRACT FROM AUTHOR]

To characterize focal biomechanical alterations in subclinical keratoconus (SKC) using motion-tracking (MT) Brillouin microscopy and evaluate the ability of MT Brillouin metrics to differentiate eyes with SKC from normal control eyes. Prospective cross-sectional study. Thirty eyes from 30 patients were evaluated, including 15 eyes from 15 bilaterally normal patients and 15 eyes with SKC from 15 patients. All patients underwent Scheimpflug tomography and MT Brillouin microscopy using a custom-built device. Mean and minimum MT Brillouin values within the anterior plateau region and anterior 150 μm were generated. Scheimpflug metrics evaluated included inferior–superior (IS) value, maximum keratometry (K max), thinnest corneal thickness, asymmetry indices, Belin/Ambrosio display total deviation, and Ambrosio relational thickness. Receiver operating characteristic (ROC) curves were generated for all Scheimpflug and MT Brillouin metrics evaluated to determine the area under the ROC curve (AUC), sensitivity, and specificity for each variable. Discriminative performance based on AUC, sensitivity, and specificity. No significant differences were found between groups for age, sex, manifest refraction spherical equivalent, corrected distance visual acuity, K max , or KISA% index. Among Scheimpflug metrics, significant differences were found between groups for thinnest corneal thickness (556 μm vs. 522 μm; P < 0.001), IS value (0.29 diopter [D] vs. 1.05 D; P < 0.001), index of vertical asymmetry (IVA; 0.10 vs. 0.19; P < 0.001), and keratoconus index (1.01 vs. 1.05; P < 0.001), and no significant differences were found for any other Scheimpflug metric. Among MT Brillouin metrics, clear differences were found between control eyes and eyes with SKC for mean plateau (5.71 GHz vs. 5.68 GHz; P < 0.0001), minimum plateau (5.69 GHz vs. 5.65 GHz; P < 0.0001), mean anterior 150 μm (5.72 GHz vs. 5.68 GHz; P < 0.0001), and minimum anterior 150 μm (5.70 GHz vs. 5.66 GHz; P < 0.001). All MT Brillouin plateau and anterior 150 μm mean and minimum metrics fully differentiated groups (AUC, 1.0 for each), whereas the best performing Scheimpflug metrics were keratoconus index (AUC, 0.91), IS value (AUC, 0.89), and IVA (AUC, 0.88). Motion-tracking Brillouin microscopy metrics effectively characterize focal corneal biomechanical alterations in eyes with SKC and clearly differentiated these eyes from control eyes, including eyes that were not differentiated accurately using Scheimpflug metrics. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article. [ABSTRACT FROM AUTHOR]

Abstract Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular biometry was performed, using the Pentacam AXL, by an experienced optometrist on all the participants. The axial length (AL) measurements were taken thrice, with a gap of 10 minutes. To evaluate the repeatability, the intraclass correlation coefficient (ICC) and the repeatability coefficient (RC) were calculated. To determine the significant difference in the repeatability index among study variables, the tolerance index (TI) was calculated. Results: In this report, 897 eyes of 677 individuals aged between 20 and 91 years (mean ± SD: 64.90 ± 13.62 years) were reported. The ICC of the axial length measurements was 0.981 for all cases. Based on the within-subject standard deviation, the RC was 0.401. The ICC was 0.976 and 0.985 in men and women, respectively. The TI showed better RC of measurements among females. The ICC decreased from 0.999 in participants under 40 years to 0.973 in individuals over 60 years of age. The TI showed a decrease in RC with advancing age. The RC was worse in eyes with nuclear cataracts; the RC was also worse in the first quartile of the signal-to-noise ratio (SNR) compared to the other SNR quartiles. Conclusion: The Scheimpflug-based systemPentacam AXL had high repeatability in measuring axial length. Some variables such as male gender, older age, and nuclear cataract were associated with reduced repeatability of the measurements. A higher SNR was associated with better repeatability of the axial length measurements.

PurposeTo compare different corneal keratometry readings (swept-source-OCT-assisted biometry and Scheimpflug imaging) with a novel software platform for calculation of toric intraocular lenses.SettingDepartment of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.DesignRetrospective, non-randomized, clinical trial.MethodsTwenty-three eyes undergoing toric intraocular lens implantation were included. Inclusion criteria were preoperative regular corneal astigmatism of at least 1.00 D, no previous refractive surgery, no ocular surface diseases and no maculopathies. Lens exchange was performed with CALLISTO eye (Zeiss). For each patient, the expected postoperative residual refraction was calculated depending on three different corneal parameters of two different devices: standard K-front (K) and total keratometry (TK) obtained by a swept-source-OCT-assisted biometry system (IOL Master 700, Zeiss) as well as total corneal refractive power (TCRP) obtained by a Scheimpflug device (Pentacam AXL, Oculus). Barrett’s formula for toric intraocular lenses was used for all calculations within a novel software platform (EQ workplace, Zeiss FORUM®). Results were statistically compared with postoperative refraction calculated according to the Harris dioptric power matrix.ResultsThe standard K values (mean PE 0.02 D ± 0.45 D) and TK values (mean PE 0.09 D ± 0.43 D) of the IOL Master 700 reached similar results (p = 0.96). 78% of eyes in both K and TK groups achieved SE within ±0.5 D of attempted correction and all eyes (100%) were within ±1.0 D of attempted correction in both groups. By contrast, the prediction error in the IOL calculation using the TCRP of the Scheimpflug device was significantly greater (mean PE −0.56 D ± 0.49 D; p = 0.00 vs. standard K and p = 0.00 vs. TK) with adjusted refractive indices. Thirty-nine and Ninety-one percentage of eyes in the TCRP group achieved SE within ±0.5 D (p = 0.008 K vs. TCRP and p = 0.005 TK vs. TCRP) and ± 1.0 D (p = 0.14 vs. TCRP) of attempted correction, respectively.ConclusionAll three corneal parameters (standard K, TK, TCRP) performed well in calculating toric IOLs. The most accurate refractive outcomes in toric IOL implantation were achieved by IOL calculations based on swept-source-OCT-assisted biometry. The SS-OCT-based K-front and TK values achieve comparable results in the calculation of toric IOLs.

Purpose: This study aimed to report practice patterns in the management of keratoconus in India. Methods: An e-survey was conducted among members of the Cornea Society of India to assess preferred practice patterns for keratoconus. Results: Of the 912 members, 234 (25.7%) completed the survey. About 88.4% worked in private eye care facilities and 76.1% in cities. Of all the respondents, 91.5% had access to a Scheimpflug-based device or an Orbscan II®; 71.4% of the respondents dispensed scleral contact lenses, and 66.7% dispensed Rose K contact lenses; 92.7% of the respondents performed corneal cross-linking (CXL); and 73.1% of the respondents performed deep anterior lamellar keratoplasty (DALK). A Scheimpflug device or Orbscan II®, Rose K or scleral contact lenses, and CXL were more readily available (P < 0.05) in private eye care facilities. The diagnostic criteria for keratoconus followed by the majority of the respondents (52.1%) were increase in corneal curvature, elevation, and thickness. An increase in keratometry values greater than 0.5 or 1.0D in a 6-month to 1-year period was considered the most favored criterion for keratoconus progression. Epithelium-off, 0.1% riboflavin solution in dextran, and accelerated protocol were the more commonly reported techniques in CXL. About 77.2% of the respondents routinely performed CXL in corneas <400 microns thick. Spectacles (91.0% of the respondents) and topography-guided photorefractive keratectomy (37.6% of the respondents) were, respectively, the preferred optical and surgical methods used to improve vision. Conclusion: While keratoconus management in India is comparable to other developed healthcare systems, the concentration of trained corneal surgeons in cities and private eyecare facilities may lead to less equitable distribution of treatment across the country. [ABSTRACT FROM AUTHOR]

To assess the effect of chronic cigarette smoking on corneal and lens densitometry measurements using Pentacam HR and to compare the results obtained with those in non-smokers. This cross-sectional comparative study included 40 chronic-smokers and 40 age-matched healthy non-smokers between 18–40 years. After general ophthalmic examination, the Pentacam HR imaging system was used to evaluate corneal and lens densitometry measurements of smokers and non-smokers. The mean corneal densitometry values were not statistically significantly different in all the concentric zones and layers in the eyes of the smokers and non-smokers (p > 0.05, for all). However, the mean values of zone 1, zone 2, zone 3 and average lens densitometry measurements of the smokers were statistically significantly higher compared to non-smokers (p < 0.05, for all). Additionally, significant positive correlations were detected between the number of pack-years smoked and lens densitometry measurements. Lens densitometry measurements of smokers were significantly increased while corneal densitometry measurements were not significantly altered compared to non-smokers. Smoking may contribute to cataractogenesis and smoking and age-related changes may act synergistically to cataract development among smokers. [ABSTRACT FROM AUTHOR]

Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular biometry was performed, using the Pentacam AXL, by an experienced optometrist on all the participants. The axial length (AL) measurements were taken thrice, with a gap of 10 minutes. To evaluate the repeatability, the intraclass correlation coefficient (ICC) and the repeatability coefficient (RC) were calculated. To determine the significant difference in the repeatability index among study variables, the tolerance index (TI) was calculated. Results: In this report, 897 eyes of 677 individuals aged between 20 and 91 years (mean ±SD: 64.90 ±13.62 years) were reported. The ICC of the axial length measurements was 0.981 for all cases. Based on the within-subject standard deviation, the RC was 0.401. The ICC was 0.976 and 0.985 in men and women, respectively. The TI showed better RC of measurements among females. The ICC decreased from 0.999 in participants under 40 years to 0.973 in individuals over 60 years of age. The TI showed a decrease in RC with advancing age. The RC was worse in eyes with nuclear cataracts; the RC was also worse in the first quartile of the signal-to-noise ratio (SNR) compared to the other SNR quartiles. Conclusion: The Scheimpflug-based system Pentacam AXL had high repeatability in measuring axial length. Some variables such as male gender, older age, and nuclear cataract were associated with reduced repeatability of the measurements. A higher SNR was associated with better repeatability of the axial length measurements. [ABSTRACT FROM AUTHOR]

Purpose: The aim this study is to determine anterior chamber parameters variations induced by PreserFlo MicroShunt implantation, in the early post-operative days. Methods: This is a prospective observational study on 48 eyes undergoing PreserFlo MicroShunt implantation alone (n = 30) or combined with phacoemulsification (n = 18). Anterior chamber depth (ACD) and volume (ACV), central corneal thickness (CCT) and total corneal astigmatism (TCA) were evaluated pre-operatively, post-operatively at day-1 and at 1 week with the Pentacam tomography. Results: Intraocular pressure decreased significantly from 20.9 ± 4.0 to 8.0 ± 2.8 mmHg (p < 0.0001) and to 10.8 ± 3.7 mmHg (p = 0.0001) at day-1 and week-1, respectively. TCA varied significantly from baseline (1.5 ± 1.2 D) to both day 1 follow up (2.7 ± 1.9 D, p = 0.0003) and week 1 follow up (2.2 ± 1.6 D, p = 0.02). Nevertheless, only K1 showed a transient flattening at day 1, while K2 value didn't show any statistical variation in the early post-operative period. CCT value rose significantly at day 1 (547 ± 49 vs. 529 ± 32 µm at baseline, p = 0.04), but then returned toward pre-operative values at week 1 (537 ± 39 µm, p = 0.57). In contrast, ACD values changed insignificantly from 3.3 ± 0.9 to 3.7 ± 1.0 mm at day 1 (p = 0.21), and then stabilized at 3.4 ± 0.9 mm (p = 0.82) at week 1 follow up. ACV changed from 150.0 ± 36.2 to 159.5 ± 42.1 mm3 at day 1 (p = 0.58), and successively to 153.9 ± 37.9 mm3 at week 1 follow up (p = 0.96). The subgroup analysis in eyes undergoing standalone PreserFlo implantation didn't show significant changes in both ACD and ACV. Conclusion: PreserFlo implantation minimizes the anterior chamber modifications generated by traditional filtering surgery, inducing low and transient corneal and biometric changes only in the very early postoperative period and insignificant changes to ACD and ACV, label of its safety and minimal invasiveness. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the use of Scheimpflug tomography in corneal densitometry (CD) in comparing the stages of keratoconic eyes. Methods: Keratoconic (KC) corneas (stages 1–3 classified according to the topographic parameters) were examined using the Scheimpflug tomographer (Pentacam, Oculus) using the CD software. CD was measured over three different depths (anterior stromal layer [120 μm], posterior stromal layer [60 μm], and middle stromal layer between these two layers), and concentric annular zones (0.0 to 2.0, 2.0 to 6.0, 6.0 to 10.0, and 10.0 to 12.0 mm diameter area). Results: The study participants were divided into three groups: keratoconus (KC) stage 1 (KC1) with 64 participants, keratoconus stage 2 (KC2) with 29 participants, and keratoconus stage 3 (KC3) with 36 participants. Comparing CD of all three layers (anterior, central, and posterior) of the cornea over different circular annuli (0–2, 2–6, 6–10, and 10–12 mm) revealed a significant difference in the 6–10 mm annulus between all groups and in all layers (P = 0.3, 0.2, and 0.2, respectively). Area under curve (AUC) was done. It revealed that the central layer showed the highest specificity (93.8%) in comparing KC1 and KC2, whereas CD in the anterior layer between KC2 and KC3 had the highest specificity (86.2%). Conclusion: CD showed increased values in the anterior corneal layer and in the annulus 6–10 mm more than other locations in all stages of KC.

Pur6pose To detect epithelial thickness-based diagnostic variables to detect early keratoconus (KC) and differentiate cases of early KC from high regular astigmatism, especially if abnormal topographic changes are present. Patients and methods A total of 84 eyes with high regular astigmatism on Scheimpflug imaging were evaluated by anterior segment optical coherence tomography (AS-OCT). Imaging of the cornea as well as pachymetry and epithelial thickness mapping was done using AS-OCT via a special lens mounted to a tomographic device. The same was done using Scheimpflug imaging (CSO Sirius device). Thickness of the corneal epithelium was automatically mapped using a computer algorithm. Calculations of the following diagnostic factors were recorded: minimum, superior–inferior, minimum–maximum, root-mean-square variation, root-mean-square pattern deviation, and thickness of the zonal epithelium. Results This study analyzed 84 eyes divided into two groups: group A (n=56 eyes) had high regular astigmatism and group B (n=28 eyes) with early KC. The mean spherical refraction, cylindrical refraction, and central corneal thickness (Scheimpflug imaging) for group A were −1.16±1.02 D, −3.67±0.67, and 542.88±29.64 μm, respectively. In group A, the mean central corneal thickness and central epithelial thickness was 538.84±29.67 and 52.34±1.69 μm, respectively. The mean spherical refraction, cylindrical refraction, central corneal, and epithelial thickness mean for group B were −1.75±0.87, −4.02±0.69 D, 505.36±28.48, and 49.93±0.9 μm, respectively. A significant correlation between central epithelial thickness with anterior elevation was noted in group B (P=0.048). Conclusion AS-OCT epithelial mapping may prove to be a useful diagnostic tool for determining early development of KC.

Stefan Bandlitz,1,2 Makram Nakhoul,3 Konstantin Kotliar3 1Höhere Fachschule für Augenoptik Köln (HFAK), Cologne School of Optometry, Cologne, Germany; 2School of Life and Health Sciences, Aston University, Birmingham, UK; 3Department of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Campus Jülich, Jülich, 52428, GermanyCorrespondence: Konstantin Kotliar, Department of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Campus Jülich, Heinrich-Mussmann-Str. 1, Jülich, 52428, Germany, Tel +49 241 6009-53812, Fax +49 241 6009-53222, Email kotliar@fh-aachen.dePurpose: A precise determination of the corneal diameter is essential for the diagnosis of various ocular diseases, cataract and refractive surgery as well as for the selection and fitting of contact lenses. The aim of this study was to investigate the agreement between two automatic and one manual method for corneal diameter determination and to evaluate possible diurnal variations in corneal diameter.Patients and Methods: Horizontal white-to-white corneal diameter of 20 volunteers was measured at three different fixed times of a day with three methods: Scheimpflug method (Pentacam HR, Oculus), placido based topography (Keratograph 5M, Oculus) and manual method using an image analysis software at a slitlamp (BQ900, Haag-Streit).Results: The two-factorial analysis of variance could not show a significant effect of the different instruments (p = 0.117), the different time points (p = 0.506) and the interaction between instrument and time point (p = 0.182). Very good repeatability (intraclass correlation coefficient ICC, quartile coefficient of dispersion QCD) was found for all three devices. However, manual slitlamp measurements showed a higher QCD than the automatic measurements with the Keratograph 5M and the Pentacam HR at all measurement times.Conclusion: The manual and automated methods used in the study to determine corneal diameter showed good agreement and repeatability. No significant diurnal variations of corneal diameter were observed during the period of time studied.Keywords: corneal diameter, white-to-white, diurnal variation, Scheimpflug imaging, placido based topography, slitlamp

This study aims to apply the densitometry distribution analysis (DDA) method to study corneal densitometry depending on age and corneal region from Galilei Dual Scheimpflug Analyzer tomography. A total of 83 healthy participants aged 39.02 ± 18.34 years (range 9–81 years) were screened using a Ziemer Galilei G2. Images were analysed using the DDA, and two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. A two-way ANOVA analysis was performed to investigate whether α and β are influenced by age, corneal región (four concentric areas were considered), and their interaction. The parameters α and β statistically change with age and corneal region. A statistically significant interaction effect of 13% (α) and 11% (β) exists between age and corneal region. However, the corneal region plays a more significant role than aging in corneal densitometry; 31% (α) and 51% (β) of the variance can be attributed to the corneal region, while 28% (α) and 5% (β) can be attributed solely to aging. Corneal densitometry can be objectively assessed from Galilei G2 images using the DDA method. The corneal region plays a more significant role than aging in corneal densitometry. Consequently, general results on corneal densitometry and aging should be taken cautiously. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the use of Scheimpflug tomography in corneal densitometry (CD) in comparing the stages of keratoconic eyes. Methods: Keratoconic (KC) corneas (stages 1–3 classified according to the topographic parameters) were examined using the Scheimpflug tomographer (Pentacam, Oculus) using the CD software. CD was measured over three different depths (anterior stromal layer [120 μm], posterior stromal layer [60 μm], and middle stromal layer between these two layers), and concentric annular zones (0.0 to 2.0, 2.0 to 6.0, 6.0 to 10.0, and 10.0 to 12.0 mm diameter area). Results: The study participants were divided into three groups: keratoconus (KC) stage 1 (KC1) with 64 participants, keratoconus stage 2 (KC2) with 29 participants, and keratoconus stage 3 (KC3) with 36 participants. Comparing CD of all three layers (anterior, central, and posterior) of the cornea over different circular annuli (0–2, 2–6, 6–10, and 10–12 mm) revealed a significant difference in the 6–10 mm annulus between all groups and in all layers (P = 0.3, 0.2, and 0.2, respectively). Area under curve (AUC) was done. It revealed that the central layer showed the highest specificity (93.8%) in comparing KC1 and KC2, whereas CD in the anterior layer between KC2 and KC3 had the highest specificity (86.2%). Conclusion: CD showed increased values in the anterior corneal layer and in the annulus 6–10 mm more than other locations in all stages of KC. [ABSTRACT FROM AUTHOR]

AIM: To explore the possibility of deploying three contactless devices (static and rotating Scheimpflug technology, spectral domain optical coherence tomography) for measuring central corneal thickness (CCT) in preoperative and postoperative examinations of cataract patients. METHODS: Totally 72 patients who had undergone surgery without complications were selected. The CCT was measured prior to the operation, as well as on the first, 5th-7th and 28th day following the operation using the Nidek NT 530-P, Sirius®, and Topcon OCT-2000 devices. RESULTS: A significant postoperative increase and subsequent decrease in CCT was identified with all three devices. The correlations were highly significant and thus reflect a very good degree of comparability at all times with the exception of the rotating Scheimpflug camera. The postoperative results from the latter differed significantly from the other devices. The correlations were Sirius/Topcon (P=0.010) and Sirius/Nidek (P

This work presents theoretical and experimental studies on a binocular Scheimpflug light-field based PIV. To investigate the effects of key parameters such as magnification, camera separation angle and tilt angle, a simulation study and quantitative comparison between conventional and binocular Scheimpflug light-field PIV have been performed. To validate the performance of binocular Scheimpflug light-field PIV, a series of vortex ring experiments have been carried out with different parameters. A comparison of the reconstructed volume and quality of the resolved vortex ring structures shows the advantages of binocular Scheimpflug light-field PIV. With Scheimpflug imaging, the focal plane of two light-field cameras can be fully overlapped which results in an extended reconstructed particle volume and less distortion in the resolved flow field than conventional binocular light-field PIV. • A novel binocular Scheimpflug light-field based PIV is proposed for accurate volumetric flow field measurement. • The principle and implementation of the proposed method are described. • Theoretical investigation on the effects of key parameters is performed via simulation and quantitative comparison. • Experiments on a vortex ring flow are conducted to evaluate the proposed method using various combinations of key parameters. [ABSTRACT FROM AUTHOR]

Ramón Ruiz-Mesa, Maria Ruiz-Santos, Julia Blanch-Ruiz, Ana Jiménez-Nieto Cataract and Refractive Surgery Department, Oftalvist Jerez de la Frontera, Jerez de la Frontera, SpainCorrespondence: Ramón Ruiz-Mesa, Oftalvist Jerez de la Frontera, Avenida Puerta del Sur S/N, Jerez de la Frontera, Cádiz, 11408, Spain, Email ramonruizmesa@gmail.comPurpose: To compare the acquisition time necessary to obtain the optical biometry plus corneal power measurement using the IOLMaster 700 with central topography with that found using the standard IOLMaster 700 in combination with two corneal topographers, when acquiring biometry measurements during cataract evaluation.Methods: This prospective, observational, controlled study included 96 eyes of 96 cataract patients. Acquisition times were registered for different conditions: time required for one complete measurement with IOLMaster 700 with central topography, time required for one complete measurement with standard IOLMaster 700 (without central topography), time required for one complete measurement with standard IOLMaster 700 plus time required for one complete measurement with Cassini, and time required for one complete measurement with standard IOLMaster 700 plus time required for one complete measurement with Pentacam HR. In addition, the agreement between keratometry (K), total keratometry (TK) and equivalent K reading (EKR) parameters using the three devices was performed.Results: The post hoc Tukey’s test revealed that there were statistically significant differences for all pairwise comparisons (p < 0.001) except for the acquisition times of the IOLMaster with central topography and the standard IOLMaster 700 (p = 0.501). The acquisition time by the IOLMaster 700 with central topography takes approximately three less times than the use of a corneal topographer combined with a biometer. The agreement of K1, K2, TK1, TK2, EKR1 and EKR2 measurements between the three devices revealed statistically significant differences for all possible comparisons (p < 0.001) except for the comparison between the IOLMaster 700 and the Cassini for all parameters (p > 0.05).Conclusion: We consider that this is an efficient procedure that improves clinical flow. We also conclude that K readings obtained with the three devices cannot be used interchangeably since there are clinically relevant differences that may affect cataract surgery outcomes.Keywords: IOLMaster 700, optical biometer, cataract, Scheimpflug imaging, color LED

Objectives: The purpose of the study was to investigate the eyelid hyperlaxity, anterior segment, and corneal topographic parameters in patients with obstructive sleep apnea syndrome (OSAS) using Scheimpflug camera and topography system. Methods: In this prospective and cross-sectional clinical study, 32 eyes of 32 patients with OSAS and thirty-two eyes of 32 healthy subjects were evaluated. The participants with OSAS were selected from those with an apnea-hypopnea index = 15. The minimum corneal thickness (ThkMin), apical corneal thickness (ACT), central corneal thickness (CCT), pupillary diameter (PD), aqueous depth (AD), aqueous volume (AV), anterior chamber angle (ACA), horizontal anterior chamber diameter (HACD), corneal volume (CV), simulated K readings (sim-K), front and back corneal keratometric values at 3 mm, RMS/A values, highest point of ectasia on the anterior and posterior corneal surface (KVf, KVb), symmetry indices and keratoconus measurements were taken by combined Scheimpflug-Placido corneal topography and compared with healthy subjects. Upper eyelid hyperlaxity (UEH) and floppy eyelid syndrome were also evaluated. Results: There were no statistically significant difference between groups in terms of age, gender, PD, ACT, CV, HACD, simK readings, front and back keratometric values, RMS/A-KVf and KVb values, symmetry indices, and keratoconus measurements (p>0.05). ThkMin, CCT, AD, AV, and ACA values were significantly higher in OSAS group compared to the control (p<0.05). UEH was detected in two cases in the control group (6.3%) and in 13 cases in the OSAS group (40.6%) and the difference was significant (p<0.001). Conclusion: The anterior chamber depth, ACA, AV, CCT, and UEH increase in OSAS. These ocular morphological changes occurring in OSAS may explain why these patients prones to normotensive glaucoma. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers. Methods: This is a cross-sectional, case-control study. The AS diagnosis was made clinically. Forty-five eyes of 45 patients with AS and 38 eyes of 38 age-matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant. Results: The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = −1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10–12 mm) (r = 0.334 and P = 0.025). Conclusion: The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea's paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS.

AIM: To evaluate the clinical use of Fourier analysis of videokeratography data in the diagnosis and follow-up of keratoconus (KC). METHODS: We conducted a chart review of consecutive patients presented to our cornea clinic. A team of two experienced cornea specialists divided the patients into three groups: normal cornea, forme fruste KC (FFKC), and clinical KC. The exclusion criteria were a history of previous ocular surgery, any accompanying corneal pathology other than KC, high myopia (>6.00 diopters), amblyopia, pregnancy, breastfeeding, or any current autoimmune disease. The data of Fourier series harmonic analysis were evaluated for their diagnostic capacity using the receiver operating characteristic (ROC) curve. A binary logistic regression analysis was also conducted to construct a diagnostic model. A total of 259 eyes showed progression in the clinical KC group and underwent a combination of accelerated corneal collagen cross-linking and topography-guided customized treatment with an excimer laser. RESULTS: The study included 1262 eyes (618 normal, 530 KC, and 114 FFKC) of 1262 patients. We observed that maximum decentration (MaxDec) was almost as good as maximum keratometry (Kmax) in detecting progressive KC. The area under the curve (AUC) was 0.95 for KC [95% confidence interval (CI): 0.93-0.96] and 0.84 for FFKC (95%CI: 0.79-0.88). Higher predictive accuracy was obtained using a model combining the spherical component, MaxDec, irregularity, and regular astigmatism in the center of the cornea (AUC: 0.97; sensitivity: 89%, and specificity: 96%). CONCLUSION: Decentration, Kmax, and posterior radii of curvatures from a 3.0-mm optical zone centered on the thinnest point of the cornea provide the highest accuracy with low reproducibility of Kmax.

The purpose of this study is to quantitatively assess lens opacity, using a swept-source optical coherence tomography (SS-OCT) device for anterior segment assessment, and establish the correlation with Scheimpflug imaging, corrected distance visual acuity (CDVA) and cumulative dissipated energy (CDE). This prospective cross-sectional single-center study enrolled 51 patients (51 eyes) with crystalline lens opacity. Patients with previous ocular surgery, pathologies or general disorders affecting vision were excluded. Eyes were scanned with an SS-OCT device, and lens densitometry was automatically analyzed using a custom MATLAB script which examined lens density, nuclear density and linear density. The same analyses were performed on Scheimpflug images. Preoperative CDVA and CDE during phacoemulsification were recorded. Spearman's (ρ) and Pearson's (r) correlation coefficients were assessed according to data normality. Statistically significant correlations were established between SS-OCT and Scheimpflug imaging using lens analysis (ρ = 0.47, p < 0.001), nuclear analysis (ρ = 0.73, p < 0.001) and linear analysis (r = 0.44, p < 0.001). A significant correlation with CDE was found with all the SS-OCT methods (r = 0.57, p < 0.001). Only the nuclear analysis of the SS-OCT scans (Tb = −0.33, p < 0.01) and Pentacam Nucleus Staging (Tb = −0.26, p < 0.05) showed a statistically significant correlation with CDVA. Good inter-device agreement in lens densitometry was found. However, SS-OCT yielded improved lens imaging compared with the Scheimpflug device and a higher correlation with clinical parameters. Thus, high-resolution SS-OCT has the potential to become a preferable option for automatic cataract grading and preoperative planning. [ABSTRACT FROM AUTHOR]

Purpose: To objectively evaluate changes in lens densitometry in eyes with neovascular age-related macular degeneration (n-AMD) treated with repeated intravitreal ranibizumab injections during a 12-month period and to compare the results with those in untreated healthy fellow eyes and healthy control eyes. Methods: In this prospective study, the 36 treated eyes and the 37 untreated fellow eyes of 38 patients with n-AMD and the 32 control eyes of 32 healthy individuals were analyzed. Lens densitometry was evaluated using the Scheimpflug imaging. All data in both groups regarding lens densitometry were recorded at baseline and 12 months. Results: The mean densitometry of zone 1 in the treated eyes of patients had increased significantly at 12 months compared with the baseline (baseline: 9.3 ± 1.5, 12 months: 11.9 ± 1.7, p =.004) and was significantly greater than those measurements in the fellow eyes (9.8 ± 1.6 p =.02) and control eyes (9.6 ± 1.9, p =.01) at 12 months as well. There were no significant differences in terms of densitometry values between the fellow and control eyes at baseline and 12 months (for all, p >.05). Conclusions: Our results objectively demonstrate early nuclear lens density changes using with Scheimpflug images in eyes with n-AMD that were treated with repeated ranibizumab injections for 12 months. [ABSTRACT FROM AUTHOR]

PurposeTo assess the relationship between corneal thinning measured by clinician-graded slit-lamp examination compared with ultrasound pachymetry (USP), anterior segment optical coherence tomography (AS-OCT), and the Pentacam.MethodsPatients with corneal thinning underwent USP, AS-OCT, Pentacam measurements and standardized clinical grading by 2 cornea specialists estimating thinning on slit-lamp examination. Reproducibility of each testing modality was assessed using the intraclass correlation coefficient. Bland-Altman plots were used to determine precision and limits of agreement (LOA) between imaging modalities and clinical grading.ResultsWe included 22 patients with corneal thinning secondary to infectious or inflammatory keratitis. Mean percent stromal thinning estimated by grader 1 was 51% (SD 31) and grader 2 was 49% (SD 33). The intraclass correlation coefficient between the masked examiners was 0.95 (95% confidence interval, 0.88-0.98). Graders were more similar to each other than to any other modality with 2% difference and 4.6% of measurements outside the LOA. When measuring the area of maximum thinning, AS-OCT measured approximately 10% thicker than human graders while the Pentacam measured approximately 10% thinner than human graders with 16.7% outside the LOA. USP measured approximately 20% thinner than human graders with 5.6% outside the LOA.ConclusionsTrained corneal specialists have a high degree of agreement in location and degree of corneal thinning when measured in a standardized fashion on the same day. Other testing modalities had acceptable reproducibility and agreement with clinical examination and each other, although Scheimpflug imaging fared worse for corneal thinning, particularly in the periphery, than the other modalities.

Purpose: To report Anterior Segment Optical Coherence Tomography (ASOCT) characteristic and its usefulness in the case of Descemet's membrane (DM) anchoring caterpillar seta, highlighting the importance of vertical scans of ASOCT in detecting and delineating the deep seta and its anterior chamber (AC) penetration. Observation: A 30-year-old male patient presented with complaints of foreign body sensation and watering in the left eye after falling of an insect. Slit-lamp examination showed the presence of two caterpillar hairs, one embedded in the superficial conjunctiva and the second one embedded in the corneal stroma. Conjunctival hair was removed leading to the resolution of symptoms. ASOCT was done for deep corneal hair which showed DM breach and AC protrusion in volume vertical scans. ASOCT scan on follow-up visit showed migration of seta in AC. Deep seta being inert was not removed and the patient was closely followed. Conclusion: and IMPORTANCE: To the best of our knowledge, this is the first case reporting vertical scan imaging of caterpillar seta and showing AC migration of seta on ASOCT.

Purpose: This report describes the technique of utilizing a neutral density filter (NDF) during Scheimpflug imaging of a dense corneal opacity in order to increase data acquisition success and improve data reliability for densitometry analysis. Observations: A 49-year-old female with Steven-Johnson Syndrome secondary to sulfonamide use presented for routine follow up evaluation of her customized ocular surface prosthetic device (PD). Her ocular history was significant for mucous membrane grafting and limbal stem cell transplant in both eyes. The ocular surface examination of the left eye was notable for chronic dense neovascularization and scarring of the temporal and inferior cornea which extended into the visual axis. Scheimpflug imaging and densitometry analysis were performed in order to quantify the severity of the scar, however, there was significant difficulty in acquiring densitometry data. During a subsequent follow-up visit to monitor the scar, standardized room lighting and a neutral density filter were used to obtain reproducible and reliable imaging for densitometry analysis. The corneal scar was monitored over time using this standardized imaging protocol and by densitometry analysis minimal progression of the scar was evident, suggesting that recently documented significant vision loss in the left eye could not be attributed solely to changes in the scar. Conclusion and Importance: The use of a neutral density filter along with standardized ambient lighting conditions when performing Scheimpflug imaging may be necessary to reliably monitor densitometry progression of clinically severe corneal opacities.

• Integrated dual-modality offers a great method for accurately determining the individual corneal thickness and refractive index. • The non-contact nature of the optical imaging technique also renders it appropriate for capturing dynamic measurements. • The scheimpflug image can display the anterior segment of the eye including the complete cornea, lens (the front) and iris. • The OCT image can resolve more detailed corneal structures including the epithelium, stroma and Decemet's-endothelium complex layers. Previously we demonstrated a combined scanning-point optical coherence tomography (OCT) and Scheimpflug Imaging (SI) system, to provide cross-section images of the corneal layers and the whole anterior segment of the eye simultaneously. However, to fully realise the benefits of this dual imaging modality concept towards clinical practice, it is required that the OCT part of the system can achieve ultra-high axial resolution (<3 µ m in air) and faster imaging speeds, without using prohibitively expensive components. To achieve this, a new imaging device integrating line-field OCT and SI, using a supercontinuum light source, is demonstrated. This line-field configuration enables both OCT and SI B-scan to be captured using the same light illumination in a single shot, which is the most significant improvement over single point scanning. This achieves an OCT axial resolution down to 2.1 µ m in air (1.6 µ m in corneal tissue) and an imaging speed up to 213 kA-Scans/s. Since the OCT and SI capture the identical corneal position and serve as cross-validation, this technique offers a great method for accurately determining the individual corneal thickness and refractive index, thereby minimizing individual variations, which can help determine the extent of cutting or correction needed in vision correction. Moreover, the precise measurement of corneal thickness provided by this technique allows for a better understanding of the biomechanical properties of the cornea. We demonstrate the efficacy of the proposed system by evaluating porcine and bovine eyes ex-vivo for determining the corneal refractive index and thickness. [ABSTRACT FROM AUTHOR]

AIM: To explore single centre results of sutureless intrascleral fixation of single-piece posterior chamber intraocular lens(IOL).METHODS: In this prospective study, 50 aphakia cases were evaluated. Preoperative and postoperative visual acuity, slit lamp and fundus examination, applanation tonometry, keratometry, IOL MASTER measurement, optical coherence tomography(OCT), Scheimpflug imaging were done for an extensive evaluation.RESULTS: All IOLs were successfully implanted at the desired position without intraoperative complications. Postoperative complications included corneal edema(n=2), raised intraocular pressure(IOP)(n=3), cystoid macular edema(CME)(n=1)and decentration(n=2). All were managed to the level of good visual recovery. Surgery videos were retrospectively evaluated in cases of postoperative complications. There was no significant change in corneal astigmatism.CONCLUSION: After extensive 6mo follow up with evaluation of a variety of parameters, our technique of sutureless, glueless scleral fixation of IOL using single-piece IOL has shown favorable results and a potential option in visual rehabilitation.

A 55-year-old male presented with foreign-body sensation in the left eye, with a history of hammering a chisel. On slit-lamp evaluation, two iron corneal foreign particles with rust ring were noted. The foreign bodies were removed with 26G hypodermic needle after instilling local anesthetic drops. The purpose of this manuscript was to provide a better understanding of the role of Scheimpflug imaging in objective evaluation of corneal epithelialization in such situations. Scheimpflug imaging along with anterior segment optical coherence tomography can be used to support diagnosis, objectively monitor the healing process (epithelialization) after removal, and reveal unexpected lesions, invisible on slit-lamp biomicroscopy.

Purpose: To find the accuracy of Scheimpflug imaging for the evaluation of posterior lens capsule and to assess the incidence of pre-existing posterior capsular tear (PCT) in pediatric traumatic cataracts. Methods: It was a prospective, non-randomized, and interventional study. Scheimpflug imaging was done preoperatively to detect pre-existing PCT in pediatric traumatic cataracts after blunt trauma. All patients underwent cataract extraction with intraocular lens implantation. Intraoperatively, the posterior capsule status was noted and compared with the preoperative Scheimpflug images. Results: Forty-seven eyes of 47 children having traumatic cataracts following closed-globe injury were included. There were 32 males and 15 females with a mean age of 10.91 ± 2.75 years. The mean duration of performing the Scheimpflug imaging from injury was 41.7 ± 7.78 days. Preoperative Scheimpflug imaging showed intact posterior lens capsule in 36 eyes and PCT in 11 eyes. Intraoperative, 37 eyes had an intact posterior lens capsule and 10 eyes had PCT. The Scheimpflug imaging did not detect the PCT in three eyes (false-negative), and in four eyes, PCT was detected falsely on Scheimpflug imaging (false-positive). The sensitivity and specificity of the Scheimpflug imaging were 70 and 89.18%, respectively. The accuracy of the technique was 85.11%. Conclusion: Scheimpflug imaging is a useful modality for the detection of PCT preoperatively in cases with doubtful posterior lens capsule integrity.

Central subendothelial geographic deposits are formed as a fibrillar layer (FL) in advanced Fuchs endothelial corneal dystrophy (FECD). Previous studies demonstrated a significant decrease in corneal endothelial cell (CEC) density and an increase in focal corneal backscatter in the FL area. The present study investigated the association of the FL with edema formation and its localization. Patients (n = 96) presenting for Descemet membrane endothelial keratoplasty (DMEK) for advanced FECD were included. Slit-lamp biomicroscopy with FECD grading was followed by Scheimpflug imaging with en face backscatter analysis and pachymetric analysis. FL dimensions were measured, and correlation with pachymetric values was performed. An FL was detected in 74% of all eyes (n = 71). Pachymetric values in FL-positive versus FL-negative eyes were for corneal thickness at the apex (ACT) 614 ± 52 µm and 575 ± 46 µm (p = 0.001), for peripheral corneal thickness at 1 mm (PCT1mm) 616 ± 50 µm and 580 ± 44 µm (p = 0.002), for PCT2mm 625 ± 48 µm and 599 ± 41 µm (p = 0.017), for PCT3mm 651 ± 46 µm and 635 ± 40 µm (p = 0.128) and for PCT4mm 695 ± 52 µm and 686 ± 43 µm (p = 0.435), respectively. Correlation analysis indicated a weak correlation for the FL maximum vertical caliper diameter with ACT and PCT1mm values but no further relevant correlations. In FL-positive eyes, increased focal corneal backscatter and increased corneal thickness showed primarily central and inferotemporal localization. In conclusion, Scheimpflug imaging shows an association of the FL with increased corneal thickness in advanced FECD and shows localization of the FL and increased corneal thickness in the central and inferotemporal region. This may provide important information for progression assessment and therapeutic decision making in FECD patients in the future. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers.Methods: This is a cross-sectional, case-control study. The AS diagnosis was made clinically. Forty-five eyes of 45 patients with AS and 38 eyes of 38 age-matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant.Results: The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = -1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10-12 mm) (r = 0.334 and P = 0.025).Conclusion: The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea's paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS. [ABSTRACT FROM AUTHOR]

To assess the repeatability and reproducibility of corneal measurements performed by the Galilei G6 and determine its agreement with the Pentacam® AXL. 105 eyes underwent examination by both devices, measuring nine parameters. Paired t-tests, Deming Regression, and Bland-Altman plots were used to determine agreement. Analysis of Variance was used to determine repeatability and reproducibility. Measurements showed no clinically significant differences between the two devices. On average, the Galilei G6 measured axial length longer than the Pentacam® AXL by 0.05 mm ± 0.03 mm (p < 0.001), just 0.2% of the mean value and therefore clinically insignificant. It measured central corneal thickness and anterior chamber depth 3.77 μm ± 7.71 μm longer (p < 0.001) and 0.04 mm ± 0.07 μm shorter (p < 0.001), respectively. They are also clinically insignificant, constituting just 0.7% and 1% of the mean values. The results showed evidence of repeatability and reproducibility. Only measurements of corneal cylinder showed some clinically significant variance. The Galilei G6 and Pentacam® AXL measurements show evidence of repeatability, reproducibility, and agreement for examined parameters. Certain caution needs to be applied in cases with moderate or severe corneal cylinder, due to discrepancies in repeatability and reproducibility of corneal cylinder measurements with the Galilei G6. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of topical bimatoprost on the corneal optical density values using a dual Scheimpflug Placido analysis system. Methods: This longitudinal case–control study included 18 patients with newly diagnosed primary open-angle glaucoma who received topical bimatoprost as a first-line treatment and 20 healthy individuals (age and sex-matched controls). Corneal densitometry data were obtained using the dual Scheimpflug analyzer at pre-treatment and 1st, 6th, 12th, 18th months of post-treatment. Repeated measures of ANOVA and Pearson correlation tests were used for statistical analysis. Results: There were statistically significant differences between pre-treatment and post-treatment 1st and 6th months corneal densitometry values (p < 0.001, p = 0.007, respectively). However, there was no statistically significant difference between the post-treatment 12th and 18th months (p > 0.05). Corneal densitometry values decreased during the 1st month. Intraocular pressure (IOP) differences were statistically significant between baseline and 1 month after treatment (P < 0.001), however not statistically significant between the 1st and 6th, 6th and 12th, 12th and 18th months after treatment (p > 0.05, for all). Corneal densitometry was not correlated with IOP (r = − 0.037, p = 0.44). In the control group, there was no statistically significant difference between baseline and post-baseline 18th-month corneal densitometry measurements (p > 0.05). Conclusions: Topical bimatoprost administration might result in a decrease in corneal densitometry measurement. It is of clinical importance that topical bimatoprost administration can affect corneal transparency and cause a possible alteration in corneal properties. [ABSTRACT FROM AUTHOR]

Mohamed Hosny, Alaa Badawy, Lobna Khazbak, Mohamed Anis, Sarah Azzam Ophthalmology, Cairo University, Giza, EgyptCorrespondence: Mohamed HosnyOphthalmology, Cairo University, 84 Shehab Street, Mohandeseen, Giza 12411, EgyptTel +20 1000007675Email mohamedhosny@kasralainy.edu.egPurpose: To determine the percentage of contribution of the magnitude of posterior corneal astigmatism to total corneal astigmatism using Scheimpflug imaging.Methods: This prospective cross-sectional study was conducted on 356 eyes of 356 patients, where the total corneal astigmatism was calculated by addition of anterior and posterior corneal astigmatism using vector analysis and then the percentage of posterior to total corneal astigmatism was calculated.Results: The percentage of contribution of posterior to total corneal astigmatism was about 30% in patients with With The Rule astigmatism and about 8% in patients with Against The Rule astigmatism.Conclusion: Posterior corneal astigmatism should not be neglected during calculation of total corneal astigmatism as neglecting posterior corneal astigmatism can result in errors during calculation and correction of astigmatism.Keywords: posterior corneal astigmatism, total corneal astigmatism, Scheimpflug imaging, vector analysis

AIM: To evaluate detailed anterior segment parameters of patients with idiopathic inflammatory myopathies (IIM), including polymyositis (PM), and dermatomyositis (DM), and to clarify the associations between these data and clinical variables of IIM. METHODS: Totally 57 PM, 41 DM patients and 62 controls were enrolled in this cross-sectional, observational, case-control study. All study participants underwent Pentacam evaluation. Laboratory investigations consisted of different antibody assays, while extramuscular clinical assessments included Raynaud’s phenomenon, dysphagia, interstitial lung disease, arthritis/arthralgia, and weight loss. Objective signs and subjective symptoms of dry eye disease (DED) were also evaluated. RESULTS: All pachymetric parameters [center, apex, thinnest and maximal keratometry (Kmax)] and corneal volume (CV) of both sides of PM patients proved to be significantly lower. Some pachymetric data were also noticed as significantly decreased compared to those of controls. Several significant differences were traced between anterior segment values and extramuscular manifestations of myositis, largely in case of arthritis/arthralgia and weight loss, whereas associations between anterior segment parameters and antibodies were weak. Objective clinical tests of DED were also significantly decreased in IIM patients. CONCLUSION: The results suggest that all IIM patients have thinner corneas compared with those of controls, and decreased corneal parameters are significantly associated with the occurrence of some extramuscular manifestations. In addition, IIM patients tend to develop objective signs of DED.

Abstract Background The measurement of the pupillary function is an indispensable test in some eye examinations, being necessary the evaluation of the precision of instruments performing such measures. The aim of this study was to evaluate the intrasession repeatability of pupil size measurements provided by a multidiagnostic platform in a large sample of healthy eyes. Methods This prospective study enrolled 100 healthy eyes of 100 patients, with ages ranging from 23 to 65 years old. Repeated pupil size measures under photopic (P, 220 lx), mesopic (M, 160 lx), low mesopic (L, 70 lx), and scotopic conditions (S, 1 lx) were obtained with the VX120 system (Visionix-Luneau Technologies, Chartres, France) after a complete eye exam. Likewise, pupil size was also measured once in the fellow eye in a total of 75 eyes. The level of intrasession variability as well as differences between fellow eyes were evaluated. Results Most of differences between repeated measures did not exceed 0.5 mm (82% of S and 100% of P below this value). No significant differences between these repeated measures were found for S (p = 0.099) and L (p = 0.751). However, statistically significant differences were found between repeated measures for M (p = 0.002) and P (p = 0.003). The analysis of clinical relevance of differences between pairs (Passing-Bablok) only confirmed the clinical relevance of differences between the first and second repeated measurement of M. Concerning the comparative analysis between fellow eyes, no statistically significant differences in pupil size were found between right and left eyes in any light condition evaluated (p ≥ 0.227). Conclusions The VX120 system can provide consistent measurements of pupil size under scotopic, low mesopic and photopic conditions, with a relative limitation under mesopic conditions.

This study aims to apply the densitometry distribution analysis (DDA) method to study corneal densitometry depending on age and corneal region from Galilei Dual Scheimpflug Analyzer tomography. A total of 83 healthy participants aged 39.02 ± 18.34 years (range 9–81 years) were screened using a Ziemer Galilei G2. Images were analysed using the DDA, and two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. A two-way ANOVA analysis was performed to investigate whether α and β are influenced by age, corneal región (four concentric areas were considered), and their interaction. The parameters α and β statistically change with age and corneal region. A statistically significant interaction effect of 13% (α) and 11% (β) exists between age and corneal region. However, the corneal region plays a more significant role than aging in corneal densitometry; 31% (α) and 51% (β) of the variance can be attributed to the corneal region, while 28% (α) and 5% (β) can be attributed solely to aging. Corneal densitometry can be objectively assessed from Galilei G2 images using the DDA method. The corneal region plays a more significant role than aging in corneal densitometry. Consequently, general results on corneal densitometry and aging should be taken cautiously.

PurposeTo evaluate measurement precision and to compare the Pentacam AXL (Oculus Optikgeräte, Wetzlar, German), a new optical biometer based on Scheimpflug imaging and partial coherence interferometry (PCI) with that of the OA-2000 biometer (Tomey, Nagoya, Japan), which combines swept-source optical coherence tomography (SS-OCT) and Placido-disk topography.MethodsAxial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), mean keratometry (Km), astigmatism vectors J0, J45, and corneal diameter (CD) were measured in triplicate by two technical operators. Within-subject standard deviation (Sw), repeatability and reproducibility (2.77 Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to assess the Pentacam AXL intra-observer repeatability and inter-observer reproducibility. Paired t-test and Bland-Altman plots were used to determine the agreement between the two biometers.ResultsThe new optical biometer had high intra-observer repeatability [all parameters evaluated had low CoV (0.88)]. Inter-observer reproducibility was also excellent, with high ICC (>0.95) and low CoV (