Scheimpflug Imaging Research Articles

Automatic Quantitative Assessment of Lens Opacities Using Two Anterior Segment Imaging Techniques: Correlation with Functional and Surgical Metrics.

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.

New artificial intelligence index based on Scheimpflug corneal tomography to distinguish subclinical keratoconus from healthy corneas.

To assess the efficiency of an index derived from multiple logistic regression analysis (MLRA) to measure differences in corneal tomography findings between subclinical keratoconus (KC) in 1 eye, corneal ectasia, and healthy corneas. 2 private Brazilian ophthalmological centers. Multicenter case-control study. This study included 187 eyes with very asymmetric ectasia and with normal corneal topography and tomography (VAE-NTT) in the VAE-NTT group, 2296 eyes with healthy corneas in the control group (CG), and 410 eyes with ectasia in the ectasia group. An index, termed as Boosted Ectasia Susceptibility Tomography Index (BESTi), was derived using MLRA to identify a cutoff point to distinguish patients in the 3 groups. The groups were divided into 2 subgroups with an equal number of patients: validation set and external validation (EV) set. 2893 patients with 2893 eyes were included. BESTi had an area under the curve (AUC) of 0.91 with 86.02% sensitivity (Se) and 83.97% specificity (Sp) between CG and the VAE-NTT group in the EV set, which was significantly greater than those of the Belin-Ambrósio Deviation Index (BAD-D) (AUC: 0.81; Se: 66.67%; Sp: 82.67%; P < .0001) and Pentacam random forest index (PRFI) (AUC: 0.87; Se: 78.49%; Sp: 79.88%; P = .021). BESTi facilitated early detection of ectasia in subclinical KC and demonstrated higher Se and Sp than PRFI and BAD-D for detecting subclinical KC.

Quantifying contact lens-related changes in keratoconus corneal topographic indices: an updated Pentacam Scheimpflug imaging analysis.

Purpose: Slowing ectasia progression is critical for maintaining visual potential in keratoconus (KC), for which various therapeutic approaches have been implemented. A Pentacam Scheimpflug imaging device was used to quantify contact lens (CL)-related changes in keratoconus corneal topographic indices. Methods: Thirty KC patients (group 1; 60 eyes) were using one of the three CL (rigid gas-permeable CL (RGPCL)-10, hybrid CL (HCL)-10, and scleral CL (SCL)-10 patients). A control group included 30 KC patients (group 2; 60 eyes) not using CLs due to intolerance or inappropriateness. The Pentacam® HR Scheimpflug imaging device was used to measure topographic indices such as Km anterior, Km posterior, K max, corneal thickness (CT, corneal central, apex, and thinnest), corneal volume (CV), anterior chamber volume (ACV), and anterior chamber depth (ACD) at baseline, 3rd, 6th, and 12th months. Results: The mean ages for groups 1 and 2 were 32±10 and 31±09 years, respectively. Group 1 had a lower but statistically significant change in K max than group 2 (p<0.038). Also, group 1 had a minor but non-significant decrease in anterior and posterior keratometry values compared to group 2 (pKm ant. right/ left eye = 0.063/ 0.065 and 0.087/ 0.094, respectively). RGPCL users had significant changes in central CT, thinnest CT and ACD (p<0.041). SCL users had more stable changes than other CLs for the thinnest CT along with significant changes in K max, pachy apex and ACV (p<0.036). HCL users had significantly higher K max stability (p<0.039). Conclusion: Regular use of appropriate therapeutic CLs may help to stabilize corneal deformity, thereby slowing changes in corneal topographic indices in KC.

Assessment of the corneal biomechanical features of granular corneal dystrophy type 2 using dynamic ultra-high-speed Scheimpflug imaging.

To evaluate the corneal biomechanical features of eyes with granular corneal dystrophy type 2 (GCD2) by analyzing corneal biomechanical indices obtained using a Corvis ST (CST) dynamic ultra-high-speed Scheimpflug imaging device. In this retrospective case-control study, 35 CST parameters were compared in normal eyes (control) and eyes of patients with GCD2 treated at Osaka University Hospital, Osaka, Japan. The parameters included the Corvis Biomechanical Index (CBI), which is important in differentiating eyes with keratoconus from normal eyes. We measured the deposition rates of lesions in the central 7-mm region of the eye and assessed the correlation between the deposition rate and the CBI. Twenty-one eyes with GCD2 and 23 control eyes were analyzed. Eyes with GCD2 showed significantly less corneal stiffness in 15 CST parameters than did control eyes. In particular, the CBI was remarkably higher in eyes with GCD2 than in control eyes (P = 0.000006). Additionally, the deposition rate and the CBI were positively correlated. GCD2 eyes had softer corneas than did control eyes in most biomechanical CST parameters, and one of the parameters (the CBI) was linked to the rate of deposited lesions. Since IOP may be underestimated in GCD2 eyes, management should be especially careful in GCD2 cases complicated by glaucoma.

Corneal aberrations, densitometry on scheimpflug imaging, and visual acuity after deep anterior lamellar keratoplasty.

To evaluate visual acuity, corneal aberrations, and densitometry post deep anterior lamellar keratoplasty (DALK). Twenty-five eyes of 25 patients who underwent DALK for corneal stromal diseases with normal endothelium were enrolled in a prospective interventional study. Evaluation for corneal aberrations and densitometry postoperatively was performed using Scheimpflug imaging at 6 months. Anterior Segment Optical Coherence Tomography (ASOCT) was done for host-graft morphology. Correlation analysis of postoperative best-corrected visual acuity with corneal aberrations and corneal densitometry (CD) was performed. Big bubble deep anterior lamellar keratoplasty (BB-DALK) was successful in 18 patients, while 7 eyes underwent manual dissection due to failed BB (Big Bubble) technique. The mean BSCVA was 1.35 ± 0.46 logMAR units pre-operatively which improved to 0.36 ± 0.19 logMAR units post DALK at 6 months (P < 0.001). The mean Root Mean Square (RMS) (μm) of the magnitude of total corneal aberrations, HOA and LOA from central 6mm zone of cornea were 14.6 ± 9.2, 4.7 ± 2.9, and 13.8 ± 8.8, respectively. The mean anterior (120μm), central and posterior corneal (60μm) densitometry in 0-2mm zone were 25.8 ± 7.7 GSU, 18.7 ± 4.16 GSU and 10.09 ± 3.9 GSU respectively. A statistically significant correlation of postoperative residual stromal bed thickness, total corneal HOA, LOA, total corneal aberrations, HOA front and posterior corneal densitometry (0-2mm zone) with postoperative BSCVA was found. Though there is a significant improvement in BSCVA after DALK, the quality of vision in terms of aberrometry and densitometry is suboptimal, especially in cases undergoing manual DALK compared to those undergoing big bubble formation.

In vivo confocal microscopy of sub-basal corneal nerves and corneal densitometry after three kinds of refractive procedures for high myopia.

To observe corneal nerve fibers and densitometry after small incision lenticule extraction (SMILE), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and laser-assisted subepithelial keratomileusis (LASEK) for high myopia. This is a prospective, cross-sectional research study. Patients with high myopia (equivalent spherical lens: -6.00 and -11.00D) who underwent laser corneal refractive surgery were divided into three groups: SMILE, FS-LASIK and LASEK. Scheimpflug imaging of corneal nerves in five areas was observed by confocal microscopy before and 6, 12months after surgery. Corneal densitometry was measured by Pentacam anterior segment analysis system. Overall, 59 patients were enrolled. The nerve density in the central area did not recover to the preoperative level in three groups until 12months. The density and length of corneal nerves in central and lower area were better in the SMILE group 6months postoperatively (p = 0.01), while nerve density did not differ significantly among three groups 12months postoperatively (p = 0.18). Nerve fibers in central and temporal region were wider in LASEK than that in other two groups at 6- and 12-month follow-up. Corneal densitometry in the central 6mm diameter was significantly higher in the LASEK group compared with other two groups 6months postoperatively (p = 0.04). Twelvemonths postoperatively, corneal densitometry in range of all zone was lower in SMILE than in FS-LASIK and LASEK (p = 0.01, 0.03, 0.04). Compared with FS-LASIK and LASEK, SMILE-treated eyes with high myopia had certain advantages in nerve density, length and nerve connection way and had better corneal transparency after operation.

Influence of Specialty Contact Lens Wear on Posterior Corneal Tomography in Keratoconus Subjects.

To evaluate the effect of specialty contact lens (CL) wear on posterior corneal tomography in keratoconus subjects. Patients with keratoconus who were wearing specialty CL were included in this retrospective cohort study. Tomographic parameters were evaluated with Scheimpflug imaging (Pentacam HR) before lens fitting and immediately after removal of CLs worn habitually for a period of several months. Subjects were divided into groups, according to type of lens (corneal, scleral, and hybrid) and keratoconus severity based on Belin/Ambrosio D (BAD-D) score, for further analysis. Thirty-four eyes of 34 subjects diagnosed with keratoconus were included. Mean duration of habitual CL wear was 7.0±0.3 months. For the entire cohort, a small increase in flat keratometric reading at the anterior corneal surface (K1F; P =0.032) and at the posterior surface (K1B; P =0.041) was found. In the corneal CL group (10 eyes; 29.4%), flattening of the anterior corneal curvature was detected (K max ; P =0.015). An increase in K1B value was seen in the scleral CL group (15 eyes; 44.1%) ( P =0.03). Combined topometric indices showed a small but significant difference in the entire cohort ( P <0.05) and in the subgroups of corneal CL wear and of moderate keratoconus (BAD-D score≥7). Various types of specialty CLs exert a differential influence on corneal parameters. A small steepening of keratometry at the posterior surface (K1B) was observed in the scleral lens group. Although corneal lens wear flattens the anterior cornea (K max ), it does not significantly alter the posterior corneal surface.

Keratoconus: current aspects of diagnosis and classification

Keratoconus (KC) is a progressive non-inflammatory ectatic corneal disease typified by corneal thinning and conical protrusion, as well as irregular astigmatism with a varying-degree visual impairment. A literature review on the disease epidemiology, classification and diagnosis is presented. Current clinical practice most commonly relies on the Krumeich’s adaptation of ABCD grading system by M. Belin and M. Amsler. The KC diagnosis requires a comprehensive approach that integrates a variety of methods. Scheimpflug imaging with the corneal biochemistry assessment is performed with a Pentacam Oculus keratotomograph in combination with a Corvis ST device. The result is expressed as diagnostic indices, CBI (Corvis Biomechanical Index), BAD-D (Belin/Ambrósio Enhanced Ectasia Index total deviation) and TBI (Tomographic Biomechanical Index). The use of optical coherence tomography is necessary to perform corneal epithelial thickness mapping as well as pachymetry to rule out hidden stromal thinning.

Evaluation of Corneal and Lens Densitometry with Scheimpflug Imaging in Young Beta Thalassemia Patients

The aim of this study is to compare corneal and lens density of children with Beta (β) thalassemia and healthy controls using Pentacam HR. This is a case-control and cross-sectional study. Anterior segment parameters, corneal, and lens densitometry of patients with β-thalassemia and healthy controls were evaluated with Scheimpflug corneal topography. For corneal densitometry analysis, the 12 mm diameter area of the cornea was divided into four concentric radial zones and anterior, central, and posterior layers according to corneal depth. The mean densitometry value for the crystalline lens was calculated in three regions around the center of the pupil. Non-contact specular microscopy was used to examine the morphology of the corneal endothelium. The study group consisted of 32 β-thalassemia major patients and the control group consisted of 31 healthy volunteers. The mean age of the study group was 12.12±3.94 years (range: 5-19 years) and 10.90±3.84 years (range: 5-19 years) in the control group (P&gt;0.05). Corneal light backscattering in the posterior layer was significantly lower in the patient group than in the control group. Corneal endothelial cell density was determined as 3053.55±189.71 in the patient group and 3214±195.12 in the control group (P=0.094). Lens densitometry values did not differ between the two groups (P&gt;0.05). We detected changes in corneal densitometry examination without any clinical findings in patients with β-thalassemia major. Pentacam may be a suitable screening technique for early detection of β-thalassemia ocular signs in children. Prospective studies with a large number of cases are needed to support these findings.

Comparison of the Functional Optical Zone in Eyes With High Myopia With High Astigmatism After SMILE and FS-LASIK.

To compare the functional optical zone (FOZ) in eyes with high myopia with high astigmatism after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). In total, 45 eyes of 45 patients with high myopia with astigmatism greater than 2.00 diopters (D) who underwent SMILE or FS-LASIK were enrolled. The FOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then compared between the two groups 6 months postoperatively. No postoperative complications were observed during follow-up. The mean FOZ diameter was 5.03 ± 0.31 mm for the FS-LASIK group and 5.24 ± 0.27 mm for the SMILE group (P = .007), corresponding to reductions of 1.18 ± 0.23 and 1.01 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .013). A significant difference was noted in the FOZ on the short axis between the two groups (P = .002), whereas no significant difference was observed on the long axis (P = .088). The FOZ area in the FS-LASIK and SMILE groups was 65.39 ± 6.14% and 70.09 ± 5.46% of the POZ area, respectively (P = .010). There was no significant difference in decentration between the two groups (0.29 ± 0.13 mm for the FS-LASIK group vs 0.30 ± 0.13 mm for the SMILE group, P = .798). A significant increase in spherical aberration was observed in the FS-LASIK group (P < .001). However, the induction of vertical coma was higher in the SMILE group than in the FS-LASIK group (P = .002). Eyes with high myopia with high astigmatism following SMILE achieved a larger FOZ and less spherical aberration but a larger vertical coma introduction than following FS-LASIK. [J Refract Surg. 2022;38(9):595-601.].

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.

Loss of Corneal Nerves and Corneal Haze in Patients with Fuchs’ Endothelial Corneal Dystrophy with the Transcription Factor 4 Gene Trinucleotide Repeat Expansion

ObjectiveSeventy percent of Fuchs’ endothelial corneal dystrophy (FECD) cases are caused by an intronic trinucleotide repeat expansion in the transcription factor 4 gene (TCF4). The objective of this study was to characterize the corneal subbasal nerve plexus and corneal haze in patients with FECD with (RE+) and without the trinucleotide repeat expansion (RE−) and to assess the correlation of these parameters with disease severity.DesignCross-sectional, single-center study.ParticipantsFifty-two eyes of 29 subjects with a modified Krachmer grade of FECD severity from 1 to 6 were included in the study. Fifteen of the 29 subjects carried an expanded TCF4 allele length of ≥ 40 cytosine-thymine-guanine repeats (RE+).Main Outcomes MeasuresIn vivo confocal microscopy assessments of corneal nerve fiber length (CNFL), corneal nerve branch density, corneal nerve fiber density (CNFD), and anterior corneal stromal backscatter (haze); Scheimpflug tomography densitometry measurements of haze in anterior, central, and posterior corneal layers.ResultsUsing confocal microscopy, we detected a negative correlation between FECD severity and both CNFL and CNFD in the eyes of RE+ subjects (Spearman ρ = −0.45, P = 0.029 and ρ = −0.62, P = 0.0015, respectively) but not in the eyes of RE− subjects. Additionally, CNFD negatively correlated with the repeat length of the expanded allele in the RE+ subjects (Spearman ρ = −0.42, P = 0.038). We found a positive correlation between anterior stromal backscatter and severity in both the RE+ and RE− groups (ρ = 0.60, P = 0.0023 and ρ = 0.44, P = 0.024, respectively). The anterior, central, and posterior Scheimpflug densitometry measurements also positively correlated with severity in both the RE+ and RE− groups (P = 5.5 × 10−5, 2.5 × 10−4, and 2.9 × 10−4, respectively, after adjusting for the expansion status in a pooled analysis. However, for patients with severe FECD (Krachmer grades 5 and 6), the posterior densitometry measurements were higher in the RE+ group than in the RE− group (P < 0.05).ConclusionsLoss of corneal nerves in FECD supports the classification of the TCF4 trinucleotide repeat expansion disorder as a neurodegenerative disease. Haze in the anterior, central, and posterior cornea correlate with severity, irrespective of the genotype. Quantitative assessments of corneal nerves and corneal haze may be useful to gauge and monitor FECD disease severity in RE+ patients.

The role of preterm birth, retinopathy of prematurity and perinatal factors on corneal aberrations in adulthood: Results from the Gutenberg prematurity eye study.

Prematurity and retinopathy of prematurity (ROP) are associated with altered corneal shape and reduced visual acuity in childhood, but their long-term effects on corneal shape in later life are still unclear. This study evaluated whether prematurity and related perinatal factors are associated with corneal aberrations in adulthood. The Gutenberg Prematurity Eye Study (GPES) is a cohort study using Scheimpflug imaging of the cornea. Associations were assessed between corneal Zernike aberrations and gestational age (GA), birth weight (BW), BW percentile, ROP occurrence, ROP treatment and other perinatal factors using univariate and multivariable linear regression analyses. This study involved 444 eyes of 256 individuals born preterm (aged 28.1±8.4 years, 146 females) and 231 eyes of 132 individuals born full-term (aged 29.8±8.9 years, 77 females). Multivariable analyses revealed an association between corneal higher-order aberrations and lower birth weight percentile (B=-0.001, p< 0.001) as well as ROP treatment (B=0.120, p= 0.03). Corneal lower-order aberrations were also associated with lower birth weight percentile (B=-0.004; p= 0.001) and ROP treatment (B=0.838, p= 0.01) but not with ROP occurrence. Increased corneal aberrations were correlated with lower visual acuity and the spherical equivalent refractive error. Perinatal factors, particularly low birth weight percentile and ROP treatment lead to a more irregular corneal shape in adulthood, thereby reducing optical image quality and potentially contributing to reduced visual acuity and altered refractive error.

Impact of Fuchs Endothelial Corneal Dystrophy Severity on Scheimpflug-Derived Parameters After Descemet Membrane Endothelial Keratoplasty.

The aim of this study was to evaluate how Scheimpflug-derived parameters of eyes with Fuchs endothelial corneal dystrophy (FECD) are influenced by Descemet membrane endothelial keratoplasty (DMEK) depending on FECD severity and the presence of subclinical edema. A retrospective cohort study including 115 eyes (115 patients) that underwent DMEK for FECD and a control group of 27 eyes with nonpathological corneas was conducted. Preoperative and 6 months postoperative Scheimpflug imaging was used to analyze pachymetry, presence of tomographic features (loss of isopachs/displacement of the thinnest point/focal posterior depression), and corneal backscatter. FECD severity was based on the modified Krachmer scale and the absence/presence of subclinical edema. Scheimpflug-derived pachymetry, tomographic, and corneal backscatter parameters were correlated with FECD severity, and all changed from preoperatively to postoperatively (all P < 0.05). Postoperative central corneal thickness, anterior and posterior corneal backscatter, and presence of focal posterior depression remained different from the control group (all P < 0.05). Of eyes without preoperative clinical edema (n = 75), 18.7% showed 0 or 1 tomographic feature (no edema group) and 82.4% had 2 or 3 features (subclinical edema group). Compared with the control group, postoperative best-corrected visual acuity for the "no edema" group did not differ (0.03 ± 0.12 vs. -0.02 ± 0.08 logarithm of the minimum angle of resolution, P = 0.150) but was worse for the subclinical edema group (0.06 ± 0.08 vs. -0.02 ± 0.08 logarithm of the minimum angle of resolution, P = 0.001). For eyes without preoperative edema, more parameters reversed back to 'normal' levels than for eyes with (sub)clinical edema. Although most analyzed parameters correlated with FECD severity, corneal tomography might be best suited for objective grading of disease severity to aid in surgical decision-making.

Inter-changeability Between Anterior Segment Optical Coherence Tomography and Scheimpflug Imaging in the Evaluation of Corneal Opacity

Purpose To compare the results of corneal evaluation, either the total corneal thickness and corneal opacity depth by both technologies AS- OCT and Scheimpflug imaging by Sirius Scheimpflug placido topography. Methods sixty-eight eyes of sixty- eight consecutive patients with corneal opacities were examined by both AS-OCT and Sirius Scheimpflug imaging. Corneal thickness and corneal opacity depth were measured and compared determining the interchangeability using Bland–Altman plotting. Results Total corneal thickness was (470.32±62.10) and (463.47±56.47) by AS. OCT and Sirius Scheimpflug imaging, respectively (P value = 0.8). While the actual measurement of corneal opacity, corneal opacity depth was (135.39±119) and (85.45±128) by AS-OCT and Siris Scheimpflug imaging respectively with P value (0.004). Conclusion AS-OCT and Scheimpflug imaging Sirius may be used interchangeably for measuring both total corneal thickness, while in the determination of corneal opacity depth. the AS-OCT is superior to Scheimpflug imaging in the accuracy of determination of actual boundaries of the corneal opacity.

Normative Values for Corneal Tomography and Comparison of Both Eyes in Young Saudi Males with 20/20 Vision Using Pentacam-HR Scheimpflug Imaging.

PurposeAnterior segment evaluation using Scheimpflug imaging with the Pentacam scanner allows the acquisition of a plethora of information. It aids in screening and diagnosing corneal pathologies and determining suitability for keratorefractive procedures. This research has significant benefits in terms of establishing normative tomographic values, which is crucial in countries where Keratoconus (KC) is more prevalent, especially among young age group, along with aiding future research in the field of refractive surgery by providing relevant normative data.MethodsA retrospective review of digital corneal tomography images for a group of medically and ophthalmologically free males aged between 18 and 21 years with 20/20 unaided distant visual acuity was performed.ResultsA total of 1272 subjects (2544 eyes) were included. Findings revealed a mean maximal corneal curvature (Kmax) of 42.91 ± 1.40D (range 36.90–47.80D). The mean flat keratometry (K1) was 41.87 ± 1.31D (range 36.00–46.40D). The mean steep keratometry (K2) was 42.66 ± 1.35D (range 36.70–47.60D). The mean corneal astigmatism (CA) was 0.79 ± 0.37D (range 0.00D-2.30D). The mean central corneal thickness (CCT) was 558.53 ± 33.84 μm (range 421–677 μm). The mean thinnest corneal location thickness (TCLT) was 551.64 ± 34.08 μm (range 417–669μm). The mean corneal diameter (CD) and anterior chamber depth (ACD) were 12.13 ± 0.39 mm (range 10.50–13.60 mm) and 3.12 ± 0.29 mm (range 2.08–4.08 mm), respectively. The median differences between both eyes of the same subject were as follows: kmax difference of 0.20D (IQR 0.1–0.4); K1, K2 and CA difference of 0.20D (IQR 0.1–0.3) for all 3 parameters; CCT and TCLT difference of 5.00 μm (IQR 3.0–9.0) and 6.00 μm (IQR 3.0–10.0), respectively; CD difference of 0.10 mm (IQR 0.0–0.1); and ACD difference of 0.04 (IQR 0.02–0.06).ConclusionWe believe our data can aid in establishing normative tomographic values and acceptable differences between both eyes. Our data may also help detect subtle corneal pathology and be useful for researchers and innovators in the field of ophthalmology.

Corneal Epithelium Asymmetry in Children With Atopy: The Effect of Hand Dominance.

PurposeTo evaluate the effect of eye rubbing on the epithelial thickness profile in tomographically normal corneas by AS-OCT and to compare right and left eyes in right-handed children.MethodsThirty right-handed boys (mean age 11.2 years) with ocular allergy and history of eye rubbing were evaluated using Scheimpflug (Pentacam HR, Oculus Wetzlar, Germany) and anterior segment optical coherence tomography. Epithelial thickness (ET) and full corneal thickness (CT) parameters were compared between right and left eyes with a non-parametric Mann–Whitney test. A p-value lower than 0.05 was considered for statistical significance.ResultsNo eyes had topometric nor tomographic criteria for keratoconus. The min-max ET was lower in right eyes (−2.8 µm vs −3.5; p = 0.02). The difference between inferior and superior (I-S) octants was lower in right eyes (1.1 µm vs 1.9 µm; p = 0.03) as a result of inferotemporal thinning. The highest ET difference was registered between nasal and temporal octants and was more pronounced in the right eyes (2 µm vs 3.1 µm; p < 0.001).ConclusionAS-OCT analyses reveal different epithelial thickness patterns between the eyes in young atopic patients, likely eye rubbers. Inferior and temporal epithelial thickness seem to be more affected by thinning in the eye on the side of the dominant hand.

Eighteen-month experience of scheimpflug imaging in patients with trisomy 21 at a tertiary pediatric center

Keratoconus is a progressive corneal ectatic disorder that occurs with high frequency in patients with Down syndrome (DS).

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.

Corneal and lenticular clarity in children with inflammatory disease as assessed by Scheimpflug imaging

BackgroundCorneal and lenticular optical properties are not well-documented in pediatric patients with inflammatory diseases. Here we aimed to evaluate corneal and lenticular optical density as well as corneal morphology in children with ocular and/or systemic inflammation by Scheimpflug imaging. MethodsFifty-five eyes of 29 children with non-infectious uveitis, 56 eyes of 28 children with systemic inflammation without uveitis and 60 eyes of 31 healthy children were included. Corneal/lenticular optical density, corneal volume, central corneal thickness, keratometry were analyzed by Pentacam HR. Corneal endothelial cell density, hexagonal cell ratio and coefficient of variation were measured by specular microscope. ResultsThe mean age was 12.0 ± 3.1 years, 11.9 ± 4.0 years and 11.3 ± 3.4 years whereas the female/ratio was 15/14, 15/13 and 14/17 in uveitis, systemic inflammation and control groups respectively. Uveitis type was anterior uveitis in 16 (29.1%) eyes, intermediate uveitis in 32 (58.2%) eyes and panuveitis in 7 (12.7%) eyes. Twenty-two (40%) eyes had active uveitis whereas 33 (60%) eyes had inactive uveitis. Corneal optical density was greater in uveitis group compared with other groups (p = 0.001, Kruskal-Wallis test). Lenticular density and corneal parameters other than optical density were not different between the groups (p > 0.05). Corneal optical density was higher in active uveitis than inactive uveitis (22/33 eyes, p = 0.017). ConclusionChildren with uveitis had decreased corneal clarity compared with systemic inflammation group and healthy controls, while lenticular clarity was similar between the groups. Corneal endothelial parameters did not change significantly based on ocular/systemic inflammation. Scheimpflug imaging provides objective corneal and lenticular optical density measurements.