Scheimpflug System Research Articles

Comparison of corneal indices between normal and keratoconus (kc) using pentacam hr for patients aged 6-21 years

OBJECTIVES: The aim is to compare normal and KC corneas using Pentacam keratometry, curvature indices, elevation indices, and pachymetry indices for patients aged between 6 to 21 years in the Riyadh area and analyze the indicators' sensitivity and specificity in differentiating between normal and KC corneas. METHOD: The present study employed a prospective, cross-sectional, observational, multicenter design to gather data from patients aged 6 to 21 who were seen in several non-ophthalmic emergency departments in Riyadh, Kingdom of Saudi Arabia, in 2017. Scheimpflug corneal tomography system in rotation was used to measure the cornea. Following optometric exams, corneal imaging and KC index measurements were performed using the Pentacam. RESULTS: Between the normal and KC groups, the majority of variables showed noteworthy statistical differences (p < 0.001). The most effective indicators for keratoconus discrimination were K Max, ISV, and IHD. K Max, ISV, and IHD each had an area under the curve of 0.94, 0.90, and 0.93. IHA, IHD, and in the paired study of the ROC curves, CKI indices performed significantly better than the other topometric variables. (p < 0.05). Nevertheless, when comparing the ROC curves with ISV, IVA, and KI pairwise, there are no statistically significant variations. Furthermore, the area under the curve (AUC) of the ROC for display TP in the pairwise comparison was smaller than that of Pachy apex (p 0.002). PPI max, ART average, and TP all had larger areas under the curves than TP (p<0.05) CONCLUSION: Pentacam indices are vital to the diagnosis of KC. K Max, ISV, and IHD are the best diagnostic indices for KC. Yet, using a combination of indices is advised to improve the diagnosis and accuracy of Pentacam indices to differentiate KC from normal.

Distribution of Belin-Ambrosio indices using Pentacam HR for normal patients aged 6 to 21 years in the Riyadh area

Objectives: To ascertain the Belin-Ambrosio indices distribution for Saudi patients aged 6-21 years in Riyadh. Method: Participants in this prospective, cross-sectional, observational, multicenter study ranged in age from 6 to 21 years old and were seen in several no n-ophthalmic emergency departments in Riyadh, Saudi Arabia, in 2017. Scheimpflug corneal tomography system in rotation was used to measure the cornea. Following optometric exams, corneal imaging and KC index measurements were performed using the Pentacam Results: The study's 366 participants were examined once the exclusion criteria were applied. All children's mean and standard deviation (SD) age was 17.41±4.83 years (range: 6–21 years). All Belin-Ambrosio indices percentiles for pediatric, adolescence, and young adult groups are within normal ranges. A comparison between Belin-Ambrosio indices and age demonstrates that the age groups have a statistically significant difference following indices topo astig, BAD Db, BAD Dp, BAD Dt, BAD Da, BAD Dy, BAD D, ART Min, ART Max and ART Avg with p-value 0.05. Also, the correlation coefficient results show a statistically significant correlation between Belin-Ambrosio indices and age with the following indices: Topo Astig, BAD Db, BAD Dp, BAD Dt, BAD Da, BAD Dy, BAD D, ART Min, ART Max, and ART Avg with p-value 0.05 as the age increases BAD Dt and BAD Dy, ART Min, ART Max, and ART Avg decrease. Also, As the age increases, the Topo Astig, BAD Db, BAD Dp, BAD Da, and BAD D increase. The correlation coefficient ranges from 0.11 negative weak to 0.65 negative moderate, and from positive 0.13 to negative strong 0.78. Conclusion:The usual range was seen in the Belin-Ambrosio indices. The Belin-Ambrosio indices and age groups differed statistically significantly.

Thinnest Point of the Cornea Compared with the Central Corneal Thickness of Myopic Eyes Measured with Pentacam Scheimpflug System

Purpose: Noncontact instruments like Pentacam Scheimpflug imaging allows assessment of corneal Pachymetry with good repeatability and reproducibility as compared to ultrasound. We aimed to differentiate corneal thinnest point and central corneal thickness on basis of magnitude and location, and its relation to age, sex, laterality, spherical equivalent and astigmatism in myopes. Study Design: Correlational study. Place and Duration of Study: Hashmanis Hospital Karachi from March 2021 to May 2021. Methods: We enrolled 92 eyes (38 males, 54 females) of myopic adult patients from age 19-52 years. Pre-screening of myopes (-0.75DS to -8.00DS) included refraction, slit-lamp biomicroscopy and fundoscopy. Participants with ocular disease, previous ocular surgery, contact lens and history of any eye drops use were excluded from the study. Pentacam was used to determine CCT, thinnest corneal thickness (TCT) and vector location of TCT. Results: Majority (77%) of the eyes had myopic astigmatism whereas 23% had simple myopia. We found statistically significant difference between CCT and TCT. Inferotemporal and inferonasal displacements of TCT were noted. No difference was noted between TCT and its location among the two sexes. We observed that alteration among the CCT and TCT in both age groups was statistically significant. Conclusion: CCT and TCT are separate measurements and both are important since their magnitudes and locations might differ greatly especially with age. Both reading have significance in determining post-operative risk of corneal ectasia, assessment for refractive surgeries and early detection of ectatic conditions like keratoconus.

Observation on the tilt and decentration of multifocal intraocular lens with optic capture in Berger space for pediatric cataract.

This study aimed to observe the tilt and decentration of multifocal intraocular lens (IOL) with optic capture in Berger space within 2 years after pediatric cataract surgery. This is a prospective observational study. The implantation of multifocal IOL (Tecnis ZMB00) with optic capture in Berger space was performed on 33 patients (48 eyes) with pediatric cataract at Qingdao Eye Hospital. Tilt and decentration of IOL was measured using Scheimpflug system (Pentacam) at 1month and 2years postoperatively. All the multifocal IOLs were successfully implanted in Berger space with optic capture and no visually significant complications were detected during the follow-up. The mean tilt of IOLs was 2.779° ± 0.950° in the vertical plane and 2.399° ± 0.898° in the horizontal plane at 1month postoperatively, and the mean length of the decentration was 0.207 ± 0.081mm in vertical plane and 0.211 ± 0.090mm in the horizontal plane. Compared with 1month after surgery, the angle of tilt decreased by a mean of 0.192° and decentration increased by a mean of 0.014mm at the vertical meridian at 2 years postoperatively (P = 0.37 and P = 0.27, respectively), meanwhile, tilt increased by 0.265° and decentration increased by 0.012mm at the horizontal meridian (P = 0.11 and P = 0.22, respectively). The follow-up results suggest the tilt and decentration of multifocal IOL implantation with optic capture in Berger space remain stable in an acceptable range within 2years after cataract surgery in children above the age of 5. The study was approved by the Ethics Committee of Qingdao Eye Hospital, and registered on Chinese Clinical Trial Registry (ChiCTR identifier: 1900023155).

Distribution of Normative Keratoconus (KC) indices for patients aged 6 to 21 Years using Pentacam HR in the Riyadh area

Objectives: To determine the distribution of Normative Keratoconus (KC) indices in normal Saudi patients aged between 6-21 years in the Riyadh area. Method: The present study employed a prospective, cross-sectional, observational, multicenter design to gather data from patients aged 6 to 21 who were seen in several non-ophthalmic emergency departments in Riyadh, Kingdom of Saudi Arabia, in 2017. Scheimpflug corneal tomography system in rotation was used to measure the cornea. Following optometric exams, corneal imaging and KC index measurements were performed using the Pentacam. Results: 366 study participants were analyzed after the exclusion criteria were applied. All children's mean and standard deviation (SD) ages were 17.41±4.83 (6–21). All the KC indices percentiles for pediatric, adolescent, and young adult groups are within normal ranges. Comparison between KC indices and age groups reveals statistically significant differences for most indices with P <0.05. As the age increases, the ISV, IVA, KI, CKI, IHA, IHD, BFS Front, BFS Back, ART Min, ART Max, ART Avg, and AC Depth decrease. Also, As the age increases, the topographic astigmatism (Topo Astig), PPI Min, PPI Max, and PPI Avg increase. There was a statistically significant correlation between KC indices and age, with most indices with P <0.05. The correlation coefficient ranges from 0.14 negative weak to 0.65 negative moderated, and from positive weak 0.22 to negative strong 0.82. Moreover, compression between KC indices and Topo Astig groups reveals statistically significant differences for most indices P <0.05. As the Topo astig increase, the K1, RSagMin PPIMax, and PPIAvg decrease. As the Topo Astig increases, the K2, ISV, IVA, CKI, IHA, BFS Back, and ACD increase. Also, there was a statistically significant correlation between Topo Astig groups and indices with P <0.05. The correlation coefficient ranges from 0.13 positive weak to 0.70 positive strong and from negative weak 0.11 to negative moderate 0.42. Conclusion: The KC indices of the current study were within normal range and comparable to prior studies. However, some indices were related to age, refractive error, and location. The normative values of multiple Pentacam indices showed statistically significant variations throughout the age groups and Topo astig subgroups.

Evaluation of anterior chamber morphology following scleral buckling with Pentacam

PurposeTo evaluate anterior segment parameter changes following scleral buckling (SB) surgery for rhegmatogenous retinal detachment (RRD) using the Pentacam Scheimpflug system. MethodsTwenty-eight phakic eyes of 28 patients who underwent SB surgery for RDD were included. The anterior chamber volume (ACV), central anterior chamber depth (CACD), mean anterior chamber angle (ACA) and ACA in a specific position (buckle quadrant), and central corneal thickness (CCT) were evaluated preoperatively and at 1 day, 1 week, and 1 and 3 months postoperatively by an anterior Pentacam Scheimpflug method. ResultsThe ACV parameters were significantly decreased compared with preoperative levels at 1 day after SB surgery (P = 0.0004), but had no significant differences at 1 week, and 1 and 3 months (P > 0.05). The mean intraocular pressure (IOP) at 1 day was significantly higher than the preoperative level, but no subsequent significant difference was noted between the preoperative IOP and that at 1 week and 1 and 3 months postoperatively (P > 0.05). The CCT at 1 day after surgery increased significantly (P = 0.0122) and subsequently returned to the normal level postoperatively at 1 week and remained stable until 3 months (P > 0.05). The degree of postoperative ACA displayed different changes in the different quadrants and there was a significant increase in the ACA of the buckle quadrants at 1 day (P < 0.0001), 1 week (P = 0.02), and 1 month (P = 0.0266) after surgery, returning to the normal level at 3 months. ConclusionsThe changes of anterior chamber parameters after SB can be demonstrated by Pentacam both objectively and quantitatively. The ACV and CCT changes were mild and resumed their preoperative parameters after 1 week, while the increase of the ACA at the buckle quadrant returned to normal after 3 months. SB surgeries without encircling or conducted with radial buckling might decrease anterior chamber change.

Angle Kappa and angle Alpha agreement between Pentacam Scheimpflug system, swept source optical coherence tomography and ray-tracing aberrometry

PurposeTo compare the consistency of Pentacam Scheimpflug system (Pentacam® HR), ray-tracing aberrometry (iTrace), and swept source optical coherence tomography (IOLMaster 700) measurements for Angle Kappa and angle Alpha. MethodsA prospective randomized cohort study. 86 individuals (86 eyes) aged 19–45 years with best corrected vision of 4.9 or better were randomly selected from January 2022 to December 2022 in a tertiary-level hospital. Angle Kappa and angle Alpha were measured or calculated using Pentacam, iTrace, and IOLMaster 700, respectively. ResultsThe mean difference of angle Kappa between any two instruments was not statistically significant, but the mean difference of angle Alpha between both Pentacam and iTrace, Pentacam and IOLMaster 700, and iTrace and IOLMaster 700 was statistically significant (p value <0.001, 0.003, <0.001). The highest consistency of angle Kappa and the narrowest 95% LoA (-0.20 to 0.21) were found between Pentacam and iTrace according to Bland Altman plots, but between Pentacam and IOLMaster 700 according to Mountain plots. Both Bland Altman plots and Mountain plots showed the highest consistency of angle Alpha and the narrowest 95% LoA (-0.14 to 0.24) between Pentacam and iTrace. ConclusionThe mean angle Kappa among Pentacam® HR, iTrace, and IOLMaster 700 had good agreement, and the value of angle Kappa could be output directly, making it more convenient for clinical application. The measured or calculated angle Alpha had poor agreement, and ophthalmologists could refer to measurements from multiple instruments.

Comparison of different corneal imaging modalities using artificial intelligence for diagnosis of keratoconus: a systematic review and meta-analysis.

This review was designed to compare different corneal imaging modalities using artificial intelligence (AI) for the diagnosis of keratoconus (KCN), subclinical KCN (SKCN), and forme fruste KCN (FFKCN). A comprehensive systematic search was conducted in scientific databases, including Web of Science, PubMed, Scopus, and Google Scholar based on the PRISMA statement. Two independent reviewers assessed all potential publications on AI and KCN up to March 2022. The Critical Appraisal Skills Program (CASP) 11-item checklist was used to evaluate the validity of the studies. Eligible articles were categorized into three groups (KCN, SKCN, and FFKCN) and included in the meta-analysis. The pooled estimate of accuracy (PEA) was calculated for all selected articles. The initial search yielded 575 relevant publications, of which 36 met the CASP quality criteria and were included in the analysis. Qualitative assessment showed that Scheimpflug and Placido combined with biomechanical and wavefront evaluations improved KCN detection (PEA, 99.2, and 99.0, respectively). The Scheimpflug system (92.25 PEA, 95% CI, 94.76-97.51) and a combination of Scheimpflug and Placido (96.44 PEA, 95% CI, 93.13-98.19) had the highest diagnostic accuracy for the detection of SKCN and FFKCN, respectively. The meta-analysis outcomes showed no significant difference between the CASP score and accuracy of the publications (all P > 0.05). Simultaneous Scheimpflug and Placido corneal imaging methods provide high diagnostic accuracy for early detection of keratoconus. The use of AI models improves the discrimination of keratoconic eyes from normal corneas.

Comparison of Corneal Densitometry and Visual Quality after Small Incision Lenticule Extraction (SMILE) and Laser Epithelial Keratomileusis (LASEK): One-Year Comparative Study.

To investigate changes in corneal densitometry (CD) and visual quality following small incision lenticule extraction (SMILE) and laser epithelial keratomileusis (LASEK) in patients with mild-to-moderate myopia. A retrospective analysis was performed on 24 and 25 patients (46 eyes each) who underwent SMILE and LASEK, respectively, for mild-to-moderate myopia. The visual quality and CD values were recorded. Using the Pentacam Scheimpflug system, CD values were collected in three concentric optical zones at the depths of the anterior, central, and posterior layers. Efficacy, safety, predictability, corneal wavefront aberrations, and QoV scores were measured to evaluate visual quality. A correlation analysis was performed between changes in CD and clinical characteristics. There were no statistical differences in efficacy and safety indices between the two groups. At 3 months postoperatively, a pronounced reduction in several zones was observed in the LASEK group (p < 0.05), whereas no obvious change was observed in the SMILE group. There were obvious changes in the CD values in several zones in the SMILE and LASEK groups (p < 0.05) after 1 year. The magnitude of the CD changes in the anterior and central corneal layers was smaller in the SMILE group than in the LASEK group (all p < 0.05). Lower HOAs, spherical aberration, and horizontal comas of the anterior and whole corneal surfaces were observed in the SMILE group. QoV scores were similar between the two groups. CD decreased in the SMILE and LASEK groups after 1 year; there was a smaller reduction in SMILE than in LASEK. SMILE and LASEK did not differ significantly in terms of safety and effectiveness in correcting mild-to-moderate myopia.

Comparison of anterior corneal aberrations measured by Scheimpflug and Placido Disc System for myopes

BackgroundTo ascertain the agreement of corneal aberrations obtained from the Pentacam and the KR-1W in myopic populations and to investigate the influence of the level of myopia as well as the laterality on the agreement.MethodsIn this observational study, a rotating Scheimpflug camera (Pentacam AXL) and a Hartmann-Shack wavefront analyzer with Placido-disc topographer (KR-1W) were used to measure the aberrations of myopes in the anterior corneal surface by one experienced operator. All examinations were computed across a 6 mm diameter. Six subgroups were generated according to the degree of myopia (mild, moderate, and severe myopia) and the laterality of eyes (right and left eyes).ResultsThe study included 245 eyes of 170 participants. For certain anterior corneal aberrations, statistically significant differences existed between the Pentacam and the KR-1W (all P < .05). The values of Zernike (Z)(2,0), Z(2,2), Z(3,1), and Z(4,0) varied in all levels of myopia regardless of the laterality, with the values of the Pentacam constantly larger than the KR-1W in the measurement of Z(2,0), Z(2,2), and Z(4,0). For 2nd to 6th aberrations, both instruments correlated poorly to moderately. The width of limits of agreement between the two instruments was clinically too wide (> 0.1 μm) for aberrations closely correlated with visual quality, including Z(3, ± 3), Z(3, ± 1), and Z(4,0), and almost all aberrations, indicating poor agreement.ConclusionsIn clinical practice, the Pentacam based on Scheimpflug technology and the KR-1W based on Placido Disc System are not interchangeable in measuring anterior corneal aberration for myopes regardless of myopia degree and the laterality, suggesting that a consistent instrument should be selected for surgical design as well as follow-up.

Reproducibility, Repeatability, and Correlation of Central Corneal Thickness Measurement with the Pentacam Scheimpflug System and Ultrasound Pachymetry.

The importance of an accurate determination of central corneal thickness (CCT) relies on its diagnostic and therapeutic implications in glaucoma, corneal ectasias, corneal edema and endothelial function monitoring, and refractive surgery suitability, among others. We aimed to analyze the repeatability, reproducibility, correlation, and laterality variations of CCT measurements performed with the Pentacam HR and the standard of care ultrasound A-scan (USP). A cross-sectional study including CCT measurements of healthy individuals was performed by three independent examiners with the Pentacam HR and USP. Intra-observer and inter-observer variations were calculated with intra-class correlation coefficients (ICCs). Bland-Altman plots and 95% limits of agreement (95% LoA) were used to assess the agreement between devices. Linear correlation was calculated with Pearson's coefficient. Thirty individuals (60 eyes), including 10 (33.3%) men and 20 (66.6%) women, with a mean age of 30.0 ± 9.1years, were studied. No statistical differences were found in CCT measurements between Pentacam HR (range 500 - 609 µm) and USP (range 498 - 628 µm). There was a high degree of correlation in repeatability and reproducibility of each independent device (ICC > 0.90). Pearson's correlation between 1 vs. 2, 2 vs. 3, and 3 vs. 1 Pentacam HR attempts were 0.914, 0.958, and 0.925, respectively (p < 0.001). Corresponding results for USP were 0.957, 0.957, and 0.943 (p < 0.001). The Pentacam HR tended to overestimate CCT by a mean difference of 3.77 µm (95% LoA, - 24.9 - 18.4). Right eyes were also overestimated (- 3.6 ± 14.1 µm) with the Pentacam HR device, whereas left eyes were underestimated (1.3 ± 11.1 µm). The Pentacam HR device provides reliable operator-independent estimates of CCT. Right eyes exhibited a tendency to overestimate with the Pentacam HR. We suspect this difference is due to USP underestimation related to patients' position while performing the study. In clinically relevant scenarios, performing a third measurement and cautiously measuring right eyes can provide higher accuracy.

Comparison of Two Scheimpflug Systems in the Measurements of Eyes with Corneal Diameter Smaller than 11.1mm.

This article aimed to evaluate the measurements of ectasia parameters by two Scheimpflug-based tomography devices, Pentacam and Sirius, for eyes with different corneal diameters (CDs). This cross-sectional research included subjects from the Fudan University EENT Hospital Refractive Center Database that were followed once a year for at least 3years with unremarkable slit-lamp examination and normal topography. Pentacam and Sirius examinations were performed on these subjects and the ectasia indices were compared between different CD groups. The right eyes of 153 subjects were included (CD ≤ 11.1mm, n = 50; 11.2-12mm, n = 52; > 12.0mm, n = 51). For the ectasia parameters from Pentacam, CD had the greatest influence on the deviation of normality of back elevation (Db, R2 = 0.371, β = -1.119, P < 0.001), overall deviation of normality (BAD-D, R2 = 0.305, β = -0.589, P < 0.001), and minimum pachymetric progression index (PPImin, R2 = 0.282, β = -0.131, P < 0.001). For parameters derived from Sirius, CD had the greatest influence on Baiocchi-Calossi-Versaci index of the back surface (BCVb, R2 = 0.138, β = -0.179, P < 0.001), keratoconus vertex of the back surface (KVb, R2 = 0.099, β = -2.273, P < 0.001), and BCV (R2 = 0.071, β = -0.078, P = 0.001). CD had little influence on surface asymmetry index of the front (SIf) and back surface (SIb), keratoconus vertex of the front surface (KVf), Baiocchi-Calossi-Versaci index of the front surface (BCVf), and Sirius classifier (P > 0.05). For Pentacam, CD mainly influenced indices related to back elevation (BE) and pachymetry progression, whereas for Sirius, CD mainly influenced indices related to BE and corneal aberration.

Effect of cataract incision type on corneal spherical aberration.

Corneal spherical aberration (CSA) plays an important role in the ocular refractive system. However, ophthalmologists have not considered the effect of difference cataract incisions on it. The purpose of this study is to investigate the effect of transparent corneal incision (TCI) and scleral tunnel incision (STI) on CSA after the cataract phacoemulsification with foldable IOLs. One hundred ninety-three eyes (61 males and 79 females) for 1-month observation and 114 eyes (29 males and 51 females) for 3-month observation with age-related cataracts (ARC) were included in this study. CSA was measured with dilated pupil by Pentacam Scheimpflug system at 1 day preoperative and 1, 3-month postoperative. Preoperative CSA >1.00 μm was excluded. Both TCI and STI are 3 mm incisions with Infiniti system and Ozil handpiece. No significant difference of age or gender was found between TCI and STI groups in 1 or 3-month observation. In 1-month observation, preoperative CSA for TCI and STI are 0.31 ± 0.29 and 0.41 ± 0.19 μm, which of postoperative are 0.42 ± 0.17 and 0.44 ± 0.35 μm, respectively. The change of CSA is 0.11 ± 0.32 and 0.04 ± 0.33 μm (P = .233). For 3-month observation, preoperative CSA for TCI and STI are 0.32 ± 0.28 and 0.36 ± 0.23 μm, which of postoperative are 0.43 ± 0.16 and 0.39 ± 0.26 μm, respectively. The change of CSA is 0.10 ± 0.34 and 0.03 ± 0.21 μm (P = .312). For the phacoemulsification combined with foldable IOL implantation, STI has minimal effect on CSA, but TCI might increase postoperative CSA.

Çocuk ve erişkin Keratokonus hastalarında hızlandırılmış çapraz bağlama tedavisi sonrası Scheimpflug Kornea Dansitometri analizi

Amaç: On sekiz yaş altı ve 18 yaş üstünde keratokonus nedeniyle çapraz bağlama tedavisi (ÇB) uygulanan hastalardaki korneal dansitometri değişimlerini karşılaştırmalı olarak değerlendirmektir. Yöntem: Keratokonus tanısıyla ÇB uygulanan 55 hastanın 74 gözü çalışmaya alındı. 18 yaş ve altındaki hastalar grup 1’e dahil edilirken, 18 yaş üstündeki hastalar grup 2’ye dahil edildi. Hastaların ÇB öncesinde ve sonrasında Pentacam Scheimpflug görüntüleme sistemi ile kornea kalınlığı ve korneal dansitometri değerleri ölçülerek kaydedildi. Çapraz bağlama sonrası tüm hastaların kornea kalınlıkları ultrasonik pakimetri ile de ölçüldü ve Scheimpflug sistem ölçümleri ile karşılaştırma yapıldı. Bulgular: Grup 1’de ÇB öncesindeki korneal dansitometri değeri 19.84±2.67 GSU iken, işlem sonrası 21.54±3.32 GSU idi ve aradaki fark istatistiksel olarak anlamlıydı (p=0.048). Benzer şekilde Grup 2’deki dansitometri değeri ÇB öncesinde 18.74±1.56 GSU iken, işlem sonrasında 24.53±10.46 GSU idi ve aradaki fark anlamlıydı (p&amp;lt;0.0001). Grup 1’de Scheimpflug görüntüleme sistemi ile ÇB öncesi ölçülen kornea kalınlığı 473.04±24.23 µ iken, grup 2’de 467.89±29.09 µ idi. Her iki grupta ÇB sonrası kornea kalınlıkları sırasıyla 461.88±27.64 µ ve 446.42±32.76 µ idi ve aradaki fark iki grupta da istatistiksel olarak anlamlıydı (sırasıyla p=0.003, p&amp;lt;0.0001). Sonuç: Keratokonus hastalarında, ÇB sonrasında, çocuk ve erişkinlerde korneal bulanıklık oluşmaktadır. Erişkinlerde çocuklara göre daha fazla bulanıklık olmaktadır. Bulanıklığın takibinde korneal dansitometri objektif veriler sunar. Bulanıklık olan kornealarda kalınlık takibi için ultrasonik pakimetri, Scheimpflug kameraya göre daha doğru ölçümler sunabilir.

Angle Kappa agreement between Scheimpflug tomography, combined placido Scheimpflug and combined slit scanning placido systems

PurposeTo compare the measured or calculated angle Kappa using Oculus pentacam HR, Sirius and Orbscan III devices.Patients and methodsA prospective randomized cohort study, conducted on 47 eyes of 47 healthy orthotropic individuals, with an age range of 18–50 years and a corrected Snellen’s distance visual acuity (CDVA) of 0.8 decimal or better. Angle Kappa is assessed directly using Orbscan® III software version 1.8.165.1. (Bausch and Lomb Rochester, New York, United States), while Pentacam® HR 1.21r.65 (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Sirius device (CSO, version 3.2.1.60, Costruzione Strumenti Oftalmici, Florence, Italy) were used to calculate angle kappa indirectly.ResultsLeast mean difference of estimated angle Kappa was between Orbscan and Pentacam devices (− 0.18° ± 1.8), and it was statistically insignificant (p value = 0.1294). Differences between both Orbscan and Sirius, and Pentacam and Sirius were statistically significant (p value = 0.0004 and < 0.0001 consecutively). Bland Altman analysis showed a 95% confidence interval between Orbscan III and Pentacam of − 3.76 to 3.4 and between Orbscan III and Sirius of − 3.79 to 2.26.ConclusionPentacam parameters can be used as a reliable method to calculate angle kappa indirectly, without usage of any additional measurements from other machine. Sirius device parameters could also be used, but with less accurate results. A simple modification to those devices’ software to calculate it, and incorporate it in the printout is possible, and highly recommended.

Comparison of corneal tomography using a novel swept-source optical coherence tomographer and rotating Scheimpflug system in normal and keratoconus eyes: repeatability and agreement analysis

BackgroundTo determine the repeatability and agreement using corneal tomography of a swept-source optical coherence tomographer (SS-OCT) compared to a rotating Scheimpflug camera (RSC) in normal eyes and keratoconus (KC) eyes.MethodsThis prospective repeatability analysis was performed at the Department of Ophthalmology of University Hospital Carl Gustav Carus, Dresden, Germany. Forty-three normal and 57 KC eyes were enrolled in the study. Three consecutive measurements were performed by the same operator on each device. Corneal parameters of anterior and posterior corneal surface, such as simulated keratometry (SimK), as well as central and thinnest corneal thickness were evaluated. Repeatability and agreement were assessed by using the coefficient of repeatability and Bland-Altman analysis.ResultsThe repeatability of anterior corneal parameters was comparable between RSC and SS-OCT in normal eyes (repeatability < 0.5 D). Repeatability was increased in mild and moderate KC for all parameters using both devices. In moderate KC, repeatability of Kmax was 1.33 D and 0.78 D for RSC and SS-OCT, respectively. Repeatability of posterior corneal parameters was consistently better for SS-OCT. Significant offsets and wide ranges of limits of agreement were found between the devices for SimK and corneal thickness values.ConclusionsSS-OCT showed highly repeatable measurements of anterior and posterior corneal parameters in normal and KC eyes. Compared to RSC, the SS-OCT had a better repeatability of anterior corneal parameters in mild and moderate KC as well as posterior corneal parameters in all groups. Both devices should not be used interchangeably in the diagnostic process of patients.Trial registration NCT04251143 at Clinicaltrials.gov, registered on 12 March 2018, https://clinicaltrials.gov/ct2/show/NCT04251143?cond=Keratoconus&cntry=DE&city=Dresden&draw=2&rank=1

Dual-Scheimpflug-Placido-disc corneal analysis in cats.

To evaluate the corneal topography and tomography of cats using a dual Scheimpflug and Placido disc device. Sixteen mixed-breed cats (32 eyes). Cats were sedated using meperidine (4.3mg/kg/IM) and xylazine (0.5mg/kg/IM), and evaluated using the software Galilei™. Values assessed included anterior and posterior corneal curvature, total corneal power, and corneal thickness. Ten males and six females aged between 18 and 48 months were evaluated. The simulated keratometry (SimK) was 38.37± 0.83D, mean posterior keratometry -4.89 ± 0.34D, and mean total corneal power 38.04± 0.94D. The mean central corneal thickness (CCT) was 617.34± 53.38μm with a mean thinnest point of 583.74 ± 60.60 μm. The Galilei™ examination was feasible in cats, enabling a detailed study of the cornea. To the best of our knowledge, this is the first study evaluating the corneal topography and tomography of cats using a device that integrates data from a dual Scheimpflug and Placido disc system.

Comparison of preoperative angle kappa measurements in the eyes of cataract patients obtained from Pentacam Scheimpflug system, optical low-coherence reflectometry, and ray-tracing aberrometry

BackgroundAngle kappa plays a vital role in the implantation of multifocal intraocular lens (MIOL). Large angle kappa is related to a higher risk of postoperative photic phenomena. This study aims to compare preoperative angle kappa in the eyes of cataract patients obtained from the Pentacam Scheimpflug system (Pentacam), optical low-coherence reflectometry (Lenstar), and ray-tracing aberrometry (iTrace).MethodsOne hundred thirteen eyes of 113 patients with cataracts were included. Each eye was examined 3 times using all devices to obtain angle kappa and pupil diameter. When considering dependent eyes for one individual, angle kappa in both right eyes and left eyes should be analysed separately. The repeatability and reproducibility were evaluated using the within-subject standard deviation (Sw), repeatability (2.77 Sw), and intraclass correlation coefficient (ICC). The difference, correlation, and agreement between devices were evaluated by paired t-tests, Pearson tests, and Bland-Altman analysis, respectively.ResultsIntraoperator repeatability and interoperator and intersession reproducibility of angle kappa showed an Sw of less than 0.05 mm, a 2.77 Sw of 0.14 mm or less, and an ICC of more than 0.96. Angle kappa was not significantly different between Pentacam and Lenstar (P > 0.05), while angle kappa was significantly different between Pentacam and iTrace and between Lenstar and iTrace (P < 0.05). There was a strong correlation between Pentacam and Lenstar for angle kappa (r =0.907 to 0.918) and a weak or moderate correlation between Pentacam and iTrace and between Lenstar and iTrace (r =0.292 to 0.618). There were narrow 95% limits of agreement (LoA) between Pentacam and Lenstar for angle kappa and wide 95% LoA between Pentacam and iTrace and between Lenstar and iTrace. No significant differences in pupil diameter were found between Pentacam and Lenstar in either eye (P > 0.05). Positive angle kappa (nasal light reflex) was found in most cataract patients (79.25% to 84.91%) through 3 different devices in both eyes.ConclusionsThe 3 devices provided high intraoperator repeatability and interoperator and intersession reproducibility for angle kappa measurements. The measurement of preoperative angle kappa in the eyes of patients with cataracts by Pentacam and Lenstar has good agreement.

Evaluation of Intraocular Lens Tilt and Decentration in Congenital Ectopia Lentis by the Pentacam Scheimpflug System.

Purpose The purpose of this study was to quantify the characteristics of the tilt and decentration of the IOL after trans-scleral suture fixation surgery in congenital ectopia lentis (CEL) patients. Methods The clinical characteristics of 70 CEL patients at Zhongshan Ophthalmic Center in China were retrospectively analyzed. The tilt and decentration of intraocular lens (IOL) were measured by using a Pentacam and compared between different axial length (AL) subgroups. The correlation between IOL tilt, decentration, and ocular characteristics was investigated using Spearman's correlation analysis. Results The postoperative IOL position of CEL patients was mainly located nasally inferiorly. The average tilt of the IOL in CEL patients was less than 7° (for temporal: 2.21 ± 1.53°, for nasal: −1.84 ± 2.04°, for superior: 2.22 ± 2.18°, and for inferior: −1.70 ± 1.62°), and the average decentration of the IOL in CEL patients was larger than 0.4 mm (for temporal: 0.49 ± 0.38 mm, for nasal: −0.69 ± 0.46 mm, for superior: 0.72 ± 0.58 mm, and for inferior: −0.68 ± 0.54 mm). The decentration of CEL patients in the AL ≥ 26 subgroup was greater than those with AL < 24 mm and AL 24 to 26 mm subgroups (for superior: 0.72 ± 0.28 mm vs. 0.46 ± 0.25 mm and 0.48 ± 0.22 mm, all P < 0.05; for inferior: -0.94 ± 0.56 mm vs. −0.44 ± 0.26 mm and -0.44 ± 0.46 mm, all P < 0.05). IOL decentration was positively correlated with AL (for superior: r = 0.44, P=0.019; for inferior: r = 0.54, P=0.006). IOL tilt was positively correlated with AL on the superior side (r = 0.38, P=0.041). Conclusions The extent of IOL decentration after trans-scleral suture fixation was great in CEL patients, and the IOL decentration in CEL patients was significantly associated with AL.

Associated factors and distribution of posterior corneal astigmatism in a middle-aged population

ABSTRACT Clinical relevance Posterior corneal astigmatism has an important role in diagnosis and treatment of astigmatism, but it is usually overlooked. Background This cross-sectional study aimed to investigate the distribution of posterior corneal astigmatism (PCA) and its associated factors in a middle-aged population that participated in the Shahroud Eye Cohort Study (ShECS) phase II. Methods Anterior corneal astigmatism (ACA) and PCA values were measured using rotating Scheimpflug System (Pentacam HR, Oculus). With-the-rule (WTR) astigmatism was considered when the steepest corneal meridian was aligned within 90° ± 30°, and against-the-rule (ATR) astigmatism when the steepest meridian was 0 ± 30°. All the remaining values were considered as oblique astigmatism. Logistic regression models were used for evaluating the association of PCA magnitudes with other factors. Results The current study consisted of 3871 eyes with available Pentacam data. Mean age of participants was 55.4 ± 6.1 years and 1557 (40.2%) subjects were male. Means of ACA and PCA were 0.77 ± 0.67 and −0.24 ± 0.15 D, respectively. The majority of PCA consisted of WTR astigmatism (82.43%), while ACA mostly showed ATR astigmatism (55.46%). PCA > 0.3 D was associated with male sex (OR = 1.16, P-value = 0.028) and spherical equivalent (OR = 0.93, P-value = 0.011) in the adjusted model, while PCA > 0.5 dioptre was strongly associated with myopia (OR = 4.6, P-value < 0.001). Conclusion The most common forms of ACA and PCA in middle-aged Iranian adults were ATR and WTR, respectively. While the shape of posterior corneal surface remained mostly unchanged across ages of 45 to 69 years, ACA was associated with a decrease in ATR proportion. Moreover, the most significant factors associated with higher magnitudes of PCA were male sex and myopia.