Corneal Volume Research Articles

Prevalence of Keratoconus and Keratoconus Suspect among a sample of Iraqi Children with Refractive Errors: A Cross-Sectional Study

Background: Keratoconus (KC) is a chronic, bilateral, non-inflammatory degenerative condition with severe consequences. Objective: To assess the prevalence of KC and Keratoconus Suspect (KCS) in a pediatric population with astigmatic error ≥1 diopter (D) and non-axial myopia. Methods: Between March and October 2022, a cross-sectional study was done with a group of 6–18-year-old kids with an astigmatic error of ≥1 D or non-axial myopia who went to the pediatric ophthalmology clinic at Ibn Al-Haitham Teaching Eye Hospital in Baghdad, Iraq, for regular checkups. All patients got a thorough eye examination and corneal imaging using the Corneal Tomography System (CSO) Sirius equipment and Scheimpflug technology. Results: The majority of patients were females aged 110–14 years (55%). The frequencies of KC and SKC were 13.5 and 119.6%, respectively. The proportion of KC was substantially higher for those above the age of 14. Patients with KC exhibited considerably larger cylinder and axis measurements. Participants with inferior cones and an asymmetric Bow Tie exhibited greater rates of KC (51.2% and 29.4%, respectively). Except for Pachy-Thin and corneal volume mean values, all other metrics were considerably greater in KC and KCS patients than in control patients. Conclusions: The high prevalence of KC and KCS emphasizes the importance of this issue and the necessity for a systematic strategy for screening in pediatric age groups with refractive error.

The impact of postoperative nasal oxygen therapy on early-stage corneal edema in cataract patients with dynamic Scheimpflug analyze: A retrospective study.

This study aimed to assess the impact of 6 hours of postoperative nasal oxygen therapy on early-stage corneal edema in patients with nuclear cataracts of grades 3 to 4. A retrospective study involved 49 patients (49 eyes) with grades 3 to 4 nuclear cataracts undergoing phacoemulsification and intraocular lens implantation from September 2021 to September 2022. The oxygen group (27 cases) received postoperative nasal oxygen therapy for 6 hours, while the control group (22 cases) received no additional treatment. Corneal edema was evaluated 24 hours postoperatively using a slit lamp microscope, recording the edema degree. The Pentacam anterior segment analyzer measured central corneal thickness (CCT), corneal volume (CV), and corneal optical density (COD) values preoperatively and 24 hours postoperatively. The study enrolled 49 patients. Preoperatively, there were no significant differences between the 2 groups. The oxygen group and the control group exhibited significant differences in CCT, CV, and corneal optical density values before and after surgery for intragroup comparison (all P < .05). At 24 hours postoperatively, the proportion of grade 0 corneal edema in the oxygen therapy group was 59.3%, compared to 31.8% in the control group, with no statistically significant difference (P > .05). The postoperative logMAR visual acuity in the oxygen therapy group was 0.0969 (0.0969, 0.2218), and in the control group it was 0.0969 (0.2218, 0.3979), with a statistically significant difference (P < .05). In oxygen group, the CCT, CV were 585.00 (553.00, 604.00), 68.0 (61.9, 71.3) respectively, all significantly lower than 603.50 (578.50, 788.25), 73.05 (65.3, 75.73) (all P < .05). Statistically significant differences were found in overall COD, COD within specific depth and thickness ranges, and COD within the anterior layer (120 μm thickness) at 24 hours postoperatively (all P < .05). No significant difference was observed in COD values within the central and posterior layers (60 μm thickness) between the 2 groups (all P > .05). Postoperative nasal oxygen therapy for 6 hours immediately after surgery could alleviate the severity of early-stage corneal edema in patients with nuclear cataracts of grades 3 to 4.

Comparison of scansys and pentacam HR in healthy eyes

ABSTRACT 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.

Corneal aberrations are associated with low-energy meniscus injuries

BackgroundVisual impairment can cause balance problems. Therefore, visual impairment caused by an increase in corneal deviations can lead to sudden and unstable loads in the lower extremities. We aimed to investigate the possible relationship between low-energy meniscal injuries and corneal structural measures.MethodsThis prospective, observational study included individuals aged between 18–40 years with a normal body-mass index. The study group consisted of 54 patients with grade 2 or 3 meniscus injuries after low-energy activity. The control group consisted of 54 healthy individuals without any complaints in the knee joint. The corneal parameters of all participants were evaluated with a Scheimpflug corneal topography and specular microscopy device. Simulated keratometry (SimK), minimum central corneal thickness (MCCT), cylindrical diopter (ClyD), corneal volume (CVol) spheric aberrations (SphAbb), high-order aberration (HOA), coma values, and endothelial parameters were recorded.ResultsThe research and control groups were similar in terms of age, body mass index, and gender distribution. There was no significant difference between the groups in the corneal SimK and CylD, parameters. However, HOA, Coma, SphAbb, and cell variability (Cv) values were significantly higher in the study group, and contrarily MCCT, CVol, and endothelial count (Cd) values were significantly lower.ConclusionsOur findings suggest that individuals with relatively lower MCCT values tend to develop meniscal damage after low-energy activity. Hence, the loss of corneal strength in these patients may be a sign of possible weakness in the meniscus. The HOA value above 0.26, the coma value above 0.16, and the SphAbb value above 0.1 may significantly increase the possible meniscus injury.

Evaluation of anterior segment parameters between pregnancy trimesters and postpartum with pentacam scheimflug ımaging: a prospective study

PurposeTo evaluate the effect of pregnancy on the anterior chamber, corneal parameter, and intraocular pressure measurements; and compare the results between trimesters, postpartum and non-pregnant healthy age-matched women.MethodsThis prospective study included 41 pregnant women and 53 non-pregnant women. Four measurements were taken from the pregnant women, in each trimester and postpartum third month, and once from the control group. Of the individuals included in the study, anterior chamber depth (ACD), anterior chamber volume (ACV), K1 (flat keratometry), K2 (steep keratometry), Kmean (mean value of K1 and K2), anterior chamber angle (ACA), central corneal thickness (CCT), thinnest corneal thickness (TCT), astigmatism value (AST), corneal volume (CV), biometry, axial length (AL), spherical equivalent (SFEQ), intraocular lens power (ILP), VA (visual acuity) datas were recorded.ResultsWe observed a statistically significant decrease in K2, CCT, ACD, AL and CV in the postpartum period (p = 0.025, p < 0.001, p = 0.029, p = 0.005, p = 0.004 respectively) and a statistically significant increase in ACV, CCT, and TCT as the gestational week progressed in the pregnant group (p = 0.007, p < 0.001, p = 0.025, respectively). A statistically significant decrease in IOP towards to the third trimester, and an increase in the postpartum period was observed (p < 0.001). We did not observe statistically significant changes in K1, Kmean, AST, ACA, VA, ILP, and SFEQ values.ConclusionIt is important to investigate the physiological changes that may occur during pregnancy, distinguish them from pathological changes, and avoid unnecessary treatment. We consider that it’s also important to guide the timing of anterior segment surgeries such as cataract and refractive surgery and to prescribe glasses/contact lenses.

Sex and age estimation with corneal topography parameters by using machine learning algorithms and artificial neural networks

BackgroundThe aim of this study, which was based on this hypothesis, was to estimate sex and age by using a machine learning algorithm (ML) and artificial neural networks (ANN) with parameters obtained from the eyeball. The study was conducted on corneal topography images of 155 women and 155 men aged between 6 and 87 who did not have surgical intervention or pathology in their eyeballs. In the study, the individuals were divided into four different age groups 6–17, 18–34, 35–55, and 56–87. Sex and age estimation was carried out by using the numerical data of parameters obtained as a result of corneal topography imaging in ML and ANN inputs.ResultsAs a result of our study, in sex determination, a 0.98 accuracy rate (Acc) was obtained with the logistic regression algorithm, one of the ML algorithms, and 0.94 Acc was obtained with the MLCP model, one of the ANN algorithms; in age estimation, 0.84 Acc was obtained with RF algorithm, one of the ML algorithms. With the SHAP analyzer of the Random Forest algorithm, through which the effects of parameters on the overall result are evaluated, the parameter that made the highest contribution to sex estimation was found to be corneal volume, and the parameter that made the highest contribution to age estimation was found to be pupil Q parameter.ConclusionAs a result of our study, it was found that parameters obtained from the eyeball showed a high accuracy in sex and age estimation.

Correlations of Corneal Endothelial Morphology and Corneal Thickness With Anterior Segment Parameters in Healthy Individuals.

The purpose of this study was to investigate the associations between central corneal endothelial cell density (ECD), endothelial morphology, and corneal thickness (central corneal thickness) with the anterior chamber depth, corneal volume (CV), white-to-white (WTW) distance, mean anterior chamber angle (CAmean), and gender in healthy individuals. This observational study included 136 healthy volunteers. The ECD, coefficient of variation of cell area, and hexagonal cell appearance ratio (%Hex) were measured by means of specular microscopy. The central corneal thickness, anterior chamber depth, CV, WTW distance, and the angle width of 12 points were taken by the Pentacam HR Scheimpflug anterior segment imaging. The arithmetical mean of the 12 points was considered as the CAmean. We used mixed effect linear regression model for the statistical analysis of the data. ECD was positively correlated with CV ( P = 0.028), while after adjusting for age, it was negatively correlated with age ( P < 0.001). Coefficient of variation of cell area was positively correlated with CAmean ( P = 0.036), while after adjusting for age, it was positively correlated with age ( P < 0.001) and CAmean ( P = 0.005). Hex was negatively correlated with WTW ( P = 0.023) and CAmean ( P = 0.025), and after adjusting for age, this correlation remained the same ( P = 0.029 when correlated with WTW and P = 0.035 with CAmean). There were significant changes in the morphology of the corneal endothelial cells in eyes with wider anterior chamber angle. Greater pleomorphism and polymegethism of the corneal endothelium was observed in healthy patients with wider CAmean. Deepening of the anterior chamber as myopia progresses could render the corneal endothelium more fragile and susceptible to mechanical stress, which is an area worthy of further study.

Correlation between Corneal Volume and Corneal Biomechanics and Corneal Volume Significance in Staging and Diagnosing Keratoconus.

To investigate the relationship between corneal volume (CV) at different zones and corneal biomechanics in keratoconus (KC) along with the significance of CV in diagnosing and staging KC. This prospective clinical study included 456 keratoconic eyes (Group B) and 198 normal eyes (Group A). Using the topographic KC classification method, Group B was divided into subgroups based on severity (mild, moderate, and severe). The CVs of the 3 mm, 5 mm, and 7 mm zones and biomechanical parameters were obtained by Pentacam and Corvis ST. The diagnostic utility of multirange CVs at different disease stages and severity was determined using a receiver operating characteristic (ROC) curve analysis. The CV of the 7-mm zone had the strongest correlation with A1V, A2T, PD, DA ratio max (2 mm), DA ratio max (1 mm), ARTh, integrated radius, SPA1, and CBI (p < 0.01). The CVs of the Group B subgroups were significantly lower than those of Group A for each diameter range (p < 0.05). There were significant differences between the severe, mild, and moderate subgroups for the 3 mm zone (p < 0.05, all). The 3 mm zone CV exhibited better diagnostic ability in each group for distinguishing KC from the normal cornea (Groups A vs. B: area under the ROC curve (AUC) = 0.926, Groups A vs. B1: AUC = 0.894, Groups A vs. B2: AUC = 0.925, Groups A vs. B3: AUC = 0.953). The CV significantly decreased in keratoconic eyes. Progressive thinning in the 3 mm zone may be a valuable measurement for detecting and staging KC. Combining the CV examination with corneal biomechanical information may effectively enhance the ability to detect KC.

Repeatability assessment of anterior segment measurements in myopic patients using an anterior segment OCT with placido corneal topography and agreement with a swept-source OCT

BackgroundThe precision of anterior segment biometric measurements in eyes has become increasingly important in refractive surgery. The purpose of this study is to assess the repeatability of the automatic measurements provided by a new spectral-domain optical coherence tomograph (SD-OCT)/Placido topographer (MS-39, CSO) and its agreement with a swept-source OCT (SS-OCT) biometer (CASIA SS-1000, Tomey) in patients with myopia.MethodsThe right eye of 235 subjects was scanned 3 times with both devices. The evaluated parameters included central corneal radius of the steep meridian, central corneal radius of the flat meridian, mean central corneal radius, thinnest corneal thickness, central corneal thickness, anterior chamber depth, corneal volume and diameter. The intraobserver repeatability of the MS-39 measurements was calculated using intraclass correlation coefficient (ICC), within subject standard deviation, coefficient of repeatability, coefficient of variation and repeated-measures analysis of variance of the 3 repeated measurements. The agreement between the two devices was evaluated by 95% limits of agreement (LoA).ResultsThe majority of the parameters acquired from MS-39 showed high repeatability. The repeatability of corneal diameter was slightly lower than the other measurements, although the ICC remained high. Agreement with the CASIA SS-1000 was good, indicated by the Bland-Altman plots with narrow 95% LoA values for all parameters assessed.ConclusionsThe high repeatability of automatic measurements by the new device supports its clinical application in eyes with myopia, and the good agreement between the two devices indicates they could be used interchangeably for the parameters evaluated.

Associations between corneal curvature and other anterior segment biometrics in young myopic adults

To investigate the associations between corneal curvature (CC) and other anterior segment biometrics in young myopic adults. In this retrospective multi-center study, 7893 young myopic adults were included. CC and other anterior segment biometrics were measured by Scheimpflug imaging (Pentacam). CC was defined as SimK at central 3 mm area, and other anterior segment biometrics included white-to-white corneal diameter (WTW), central corneal thickness (CCT), corneal volume (CV) at 3 mm, 5 mm, and 7 mm area, anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), anterior corneal eccentricity (ACE) and asphericity (ACAP), posterior corneal eccentricity (PCE) and asphericity (PCAP), anterior chamber depth (ACD), and anterior chamber volume (ACV). Univariate regression analyses were used to assess the associations between CC and other anterior segment biometrics, and multivariate regression analyses were further performed to adjusted for age, gender and spherical equivalent. CC was higher in patients of female gender and higher myopia (all P < 0.05). Eyes in higher CC quartiles had lower WTW, thinner CCT, lower CV at 3 mm and 5 mm, lower ACD, and lower ACV (all P < 0.001), but had larger ACA, larger PCA, less PCE and less PCAP (all P < 0.001), compared to eyes in lower CC quartiles. The trends of CV at 7 mm, ACE and ACAP were inconsistent in different CC quartiles. After adjusting for age, gender and spherical equivalent with multivariate linear regression, CC was positively correlated to CV at 7 mm (βs = 0.069), ACA (βs = 0.194), PCA (βs = 0.187), ACE (βs = 0.072), PCAP (βs = 0.087), and ACD (βs = 0.027) (all P < 0.05), but was negatively correlated to WTW (βs = − 0.432), CCT (βs = − 0.087), CV-3 mm (βs = − 0.066), ACAP (βs = − 0.043), PCE (βs = − 0.062), and ACV (βs = − 0.188) (all P < 0.05). CC was associated with most of the other anterior segment biometrics in young myopic adults. These associations are important for better understanding of the interactions between different anterior segment structures in young myopic patients, and are also useful for the exploration of the pathogenesis of myopia.

A comparison of Scansys and Sirius tomography in healthy eyes

PurposeTo 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.MethodsIn 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.ResultsThe 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.ConclusionScansys 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.

Ocular biometrics in eyes with different white-to-white corneal diameter in young myopic adults.

The interactions between white-to-white corneal diameter (WTW) and other ocular biometrics are important for planning of refractive surgery and understanding of ocular structural changes in myopia, but such interactions are rarely investigated in young myopic adults. This is a retrospective study involving 7893 young myopic adults from five centers. WTW and other ocular biometrics were measured by Pentacam. The ocular biometrics included anterior corneal curvature (AK) and posterior corneal curvature (PK), central corneal thickness (CCT) and corneal volume (CV), anterior and corneal eccentricity and asphericity, anterior corneal astigmatism (ACA) and posterior corneal astigmatism, anterior chamber depth (ACD), and anterior chamber volume (ACV). The ocular biometrics were compared among eyes of different WTW quartiles. Multivariate linear regression was used to assess the linear associations between WTW and other ocular biometrics adjusting for age, gender and spherical equivalent. In eyes of different WTW quartiles, other ocular biometrics were also significantly different (all P < 0.05). After adjusting for age, gender and spherical equivalent, WTW was positively correlated to AK (β = 0.26 to 0.29), ACA (β = 0.13), anterior corneal asphericity (β = 0.05), PK (β = 0.33 to 0.34), posterior corneal asphericity (β = 0.13), ACD (β = 0.29), and ACV (β = 40.69), and was negatively correlated to CCT (β = - 6.83), CV (β = - 0.06 to - 0.78), anterior corneal eccentricity (β = - 0.035), and posterior corneal eccentricity (β = - 0.14) (all P < 0.001). In conclusion, we found that in young myopic adults, larger WTW was associated with thinner corneal thickness, flatter corneal curvature, more anterior corneal toricity, less corneal eccentricity and asphericity, and broader anterior chamber. Our findings may fill in the gap of literature, and help us better understand how the anterior segment structures interact with the WTW in myopia.

Distribution and determinants of corneal volume among healthy young Chinese adults: a cross-sectional study

BackgroundSeveral studies have previously reported the normal values of corneal volume (CV) in various populations, whereas little is known about the CV distribution in healthy young Chinese adults. Our study aimed to investigate the distribution of CV and its relationships with other ocular biometric parameters among healthy young Chinese adults.MethodsA total of 1645 eyes from 1645 students at Dali University in Yunnan Province, China, were analyzed. Pentacam was used to measure CV. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated by Corvis-ST. Other biometrical parameters, including axial length (AL), keratometry, and white-to-white (WTW) distance, were measured using IOL Master.ResultsThe mean age of the study population was 19.01 ± 0.92 years, and 68.81% of them were women. The CV was normally distributed in the whole sample, with a mean value of 61.23 ± 3.22 mm3. CV and CCT were significantly smaller in the Yi ethnic group than in the Han ethnic group (p < 0.01). CCT (coefficient: 0.085; p < 0.001) and keratometry (coefficient: 0.422; p < 0.001) were positively correlated with CV, while AL (coefficient: -0.204; p < 0.001), WTW distance (coefficient: -0.236; p < 0.001) and bIOP (coefficient: -0.06; p < 0.001) were inversely associated with CV.ConclusionsOur study provides an age-specific distribution of CV among healthy young Chinese adults. CCT, keratometry, AL, WTW distance and bIOP were important factors associated with CV.

Longitudinal Changes of Cornea Volume Measured by Means of Anterior Segment-Optical Coherence Tomography in Patients with Stable and Progressive Keratoconus.

Keratoconus is a corneal disease which results in progressive thinning and protrusion of the cornea leading to irregular astigmatism. The purpose of this study was to evaluate longitudinal changes in corneal volume (CV) occurring over time in keratoconus eyes. Consecutive patients affected by keratoconus were evaluated by means of anterior segment-optical coherence tomography (AS-OCT) at two different time points: baseline (T0) and after 1 year (T1). Anterior and posterior refractive value; corneal thickness at the thinnest point (TP) and corneal volume (CV) calculated within discs of 3, 5 and 8 mm of diameter; anterior chamber depth (ACD); and anterior chamber volume (ACV) were obtained. Enrolled patients were divided into 3 groups (groups 1, 2, 3) according to the increasing disease severity and into 2 groups (groups A, B) according to the progression or stability of the disease. Overall, 116 eyes of 116 patients (76 males and 40 females, mean age 34.76 ± 13.99 years) were included. For the entire group of keratoconus patients, in comparison with T0, mean TP decreased at T1 from 458.7 ± 52.2 µm to 454.6 ± 51.6 µm (p = 0.0004); in parallel, mean value of CV calculated at 5 mm and 8 mm decreased significantly (from 10.78 ± 0.8 at T0 to 10.75 ± 0.79 at T1 (p = 0.02), and from 32.03 ± 2.01 mm3 at T0 to 31.95 ± 1.98 at T1 (p = 0.02), respectively). Conversely, there were no statistically significant differences in CV at 3 mm from T0 to T1 (p = 0.08), as well as for ACD and ACV. Regarding the course of the disease, patients belonging to group A showed statistically significant differences from T0 to T1 for TP, and for CV at 3 mm, 5 mm and 8 mm (p < 0.0001, p < 0.0001, p < 0.001 and p = 0.0058 respectively). There were no statistically significant differences for ACD (p = 0.6916) and ACV calculated at 3, 5 and 8 mm (p = 0.7709, p = 0.3765, p = 0.2475, respectively) in group A. At the same time, no statistically significant differences for ACD (p = 0.2897) and ACV calculated at 3, 5 and 8 mm (p = 0.9849, p = 0.6420, p = 0.8338, respectively) were found in group B. There were statistically significant positive correlations between changes of TP and CV at 3 mm (r = 0.6324, p < 0.0001), 5 mm (r = 0.7622, p < 0.0001) and 8 mm (r = 0.5987 p < 0.0001). In conclusion, given the strong correlation with TP, CV might be considered an additional AS-OCT parameter to be used in association with conventional parameters when detecting longitudinal changes in keratoconic eyes.

Assessment of corneal parameters in patients with rheumatoid arthritis.

To assess the corneal parameters in rheumatoid arthritis (RA) patients. We enrolled 64 patients with RA (32 receiving biologic and 32 receiving conventional drugs) and 32 healthy subjects. Keratometric values (anterior flat [K1], steep [K2], and mean keratometry [Km]), corneal thickness from the pupil center (CCT), apex (ACT), and the thinnest point (TCT), and corneal volume (CV) were measured and compared between the groups. K1, K2, and Km values were significantly higher in the RA group (P = 0.013, P = 0.048, P = 0.027, respectively). The means of CCT, ACT, TCT, and CV were significantly lower in RA patients (P < 0.001, P < 0.001, P < 0.001, P = 0.011, respectively). When we divided RA patients into two groups according to the treatment and compared them to controls, the differences in K1, CCT, ACT, TCT and CV were significant (P = 0.030, P = 0.005, P = 0.001, P = 0.001, P = 0.034, respectively). K1 and CV values of RA-biologic group were similar to the control group (P = 0.205 and P = 0.127, respectively). Biologic agents contribute to the improvement of K1 and CV values in patients with RA.

Comparison between Early Clinical Results of Dual-Linear and Conventional Foot-Pedal Control in Phacoemulsification

Background: The aim of this study was to compare early clinical results regarding the safety and efficacy of dual-linear vs. conventional foot-pedal control in cataract surgery. Methods: This was a paired-eye contralateral, retrospective, observational study. Each patient underwent cataract surgery in both eyes: one eye with dual-linear foot-pedal control (study group) and the other eye with conventional foot-pedal control (control group). Absolute phaco time (APT), average phaco power, effective phaco time (EPT), and surgical complications were analyzed and compared. Corneal endothelial cell count, corneal thickness, corneal volume, and best-corrected distance visual acuity (BCDVA) were measured preoperatively and at 1 week, 1 month, and 3 months postoperatively. Results: A total of 94 patients (188 eyes) were enrolled. The respective APT, average phaco power, and EPT values were 7.05 ± 5.31 s, 28.4 ± 1.00, and 2.05 ± 1.56 s in the study group and 6.82 ± 6.48 s, 18.9 ± 1.74, and 1.35 ± 1.35 s in the control group. Conclusions: The average phaco power and EPT values were significantly higher in the study group. The safety of the dual-linear foot pedal was comparable to that of a conventional pedal in terms of endothelial cell loss, central corneal thickness, and surgical complications.

Evaluation of eye and serum findings in different waters in rabbits by drowning and submersion modeling.

This study investigated serum, vitreous, and anterior chamber fluid electrolyte changes, corneal thickness (CT), corneal volume (CV), anterior chamber volume (ACV), and anterior chamber depth (ACD) as an auxiliary diagnostic method in the identification of drowning in fresh or salt water. The study used 35 healthy, adult, male, white New Zealand rabbits, seperated into five groups (control, saltwater drowning (SWD), saltwater immersion (SWI), freshwater drowning (FWD), freshwater immersion (FWI)). CT, CV, ACV, and ACD measurements were made with Pentacam topography at 0, 2, and 4 h in all groups. Magnesium (mg), sodium (Na), and chlorine (Cl) were measured in the blood at 0 and 2 h, and in blood, vitreous fluid, and humor aqueous at 4 h. It was determined that CT, CV, ACV, and ACD are not of great value in drowning diagnosis and are affected by the fresh or salt water rather than drowning. Vitreous Na, Cl, and Mg levels are ineffective in determining drowning after one h. Anterior chamber fluid may provide valuable information in the differentiation freshwater - saltwater drownings at the 4th h in corpses retrieved from water. Anterior chamber fluid Na and Cl levels, especially in corpses removed from salt water, can be an easily used test that can help diagnose drowning.

Chromatic swept‐source corneal confocal microscopy ‐ A breakthrough innovation?

Methods for visual or quantitative exploration of the cellular morphology of the cornea based on inherent three‐dimensional features open up completely new diagnostic possibilities. However, previous approaches to confocal microscopy of the cornea using mechanical 3D scanning strategies are slow and thus only partially suitable for in vivo investigations. Addressing these shortcomings, the idea of developing a novel confocal microscopic technique for three‐dimensional in vivo imaging of the cellular morphology of the cornea is aimed. By exploiting induced chromatic aberration using a swept‐source laser in conjunction with a specifically designed high‐dispersion optic, an extremely fast method for focal positioning in the tissue shall be developed. Utilizing a dedicated laser line scanning, will enable the display of sectional images in real time. These are comparable to slit lamp images, but with cellular resolution. Furthermore, with an x–y scanning protocol, corneal volumes can be acquired in less than 1 s. The project thus paves the way for cellular 3D slit‐lamp microscopy and, in perspective, provides ophthalmologists with further methods for dedicated diagnostics of ocular surface diseases. This paper summarizes the concept of this novel approach.

Corneal and anterior segment parameters in patients with clinically unilateral pseudoexfoliation syndrome.

Pseudoexfoliation syndrome (PES) is an age-related systemic condition that predominantly affects ocular structures and is characterized by the deposition of material on the lens, ciliary body, zonules, corneal endothelium, iris, and pupillary margin. We compared the corneal endothelial morphology, anterior segment parameters, corneal densitometry, and corneal topographic characteristics between the clinically affected and apparently normal fellow eyes of patients with clinically unilateral PES. This was a comparative, cross-sectional study of 34 patients with clinically unilateral PES. The anterior segment was examined using a Scheimpflug imaging system, and the corneal endothelium was assessed using a noncontact specular microscope. Corneal endothelial cell density, polymegathism, and pleomorphism were assessed using the specular microscope. Furthermore, the Scheimpflug camera was used to measure the corneal power of the flat and steep axis, mean corneal power, maximum keratometry, anterior chamber angle, anterior chamber depth, anterior chamber volume, corneal volume, and the corneal thickness at the apex point, center of the pupil, and the thinnest point. Corneal densitometry was evaluated at two concentric zones (0-2 mm and 0-12 mm). In total, 68 eyes from 34 patients were ultimately included in the study. The mean (standard deviation) age of the patients was 73.38 (8.75) years (range: 50-87 years). Among the included patients, 17 (50%) were male and 17 (50%) were female. The anterior segment parameters did not significantly differ between eyes with PES and their clinically unaffected fellow eyes (all P > 0.05). Similarly, no statistically significant difference was observed in corneal endothelial morphology (all P > 0.05). Our measured parameters do not differ between the clinically affected eye and the clinically unaffected fellow eye. This supports the theory that PES is a bilateral disorder. Considering the variety of complications associated with PES, bilateral involvement should be assumed in the clinical and surgical management of patients with clinically unilateral PES. In the future, new research could increase our understanding of this syndrome.

Prevalence and associations of keratokonus among children, adults and elderly in the population‐based ural eye studies

Aims/Purpose: To estimate prevalence and associations of keratoconus in populations in Russia with an age from childhood to seniority.Methods: The study population consisted of the cohorts of three population‐based studies performed in urban and rural areas within the same geographical region in Bashkortostan/Russia: The Ural Children Eye Study (UCES; age: 6–18 years; n = 4890), Ural Eye and Medical Study (UEMS; age: 40+ years; n = 5314) and Ural Very Old Study (UVOS; age: 85+ years; n = 651). Based upon Scheimflug imaging, keratoconus was defined by a keratometric reading of ≥48 D in any eye.Results: The mean maximal and minimal corneal refractive power increased from the UCES (43.58 ± 1.50 dioptres (D) and 42.70 ± 1.42D, respectively) to the UEMS (44.26 ± 1.70 D and 43.61 ± 1.76D, resp.) and to the UVOS (45.1 ± 1.72D and 43.98 ± 1.68D, resp.). Correspondingly, keratoconus prevalence increased from the UCES (42/4890; 0.086%; 95% CI: 0.060, 0.112) to the UEMS (112/5314; 2.11%; 95% CI: 1.72, 2.49) and to the UVOS (42/651; 6.45%; 95% CI: 4.56, 8.34). In the UCES, higher keratoconus prevalence was associated (multivariable analysis) with higher birth order (OR: 2.34; 95% CI: 1.32, 4.15; p = 0.004), lower birthweight (OR: 0.99; 95% CI: 0.99, 0.99; p &lt; 0.001), and shorter axial length (OR: 0.15;9 5% CI: 0.08, 0.30; p &lt; 0.001). In the UEMS, keratoconus prevalence correlated with shorter axial length (OR: 0.15; 95% CI: 0.10, 0.23; p &lt; 0.001), larger corneal volume (OR: 1.17; 95% CI: 1.09, 1.25; p = 0.001), thicker lens (OR: 2.27; 95% CI:1.06, 5.28; p = 0.04), cortical cataract degree (OR: 1.02; 95% CI:1.01, 1.04; p = 0.01), and higher stage of age‐related macular degeneration (OR: 1.65; 95% CI: 1.09, 2.51; p = 0.02). In the UVOS, keratoconus prevalence correlated with lower educational level (OR: 0.84; 95% CI:0.71, 0.99; p = 0 0.04) and lower dynamometric hand grip force (OR: 0.92; 95% CI: 0.88, 0.97; p = 0.003).Conclusions: In this study on multiethnic groups from Russia, keratokonus prevalence increased from the paediatric group (0.09%) to the adult group (2.11%) and seniority group (6.45%), correlated mostly with biometric ocular parameters, and was in all age groups statistically independent of most systemic parameters.