Subclinical Corneal Research Articles

Cataract surgery with endothelial keratoplasty.

This review aims to provide an updated summary of the combined approach of cataract surgery with endothelial keratoplasty (EK), addressing key considerations, including intraocular lens (IOL) choice and calculation, decision between sequential and triple EK, and modifications in surgical techniques and postoperative management. Advances in imaging techniques (Scheimpflug tomography and anterior segment optical coherence tomography) have improved the ability to detect subclinical corneal edema, aiding in surgical decision-making for EK. Recent studies comparing sequential and triple-EK indicate that both methods yield similar visual outcomes. Though triple-EK offers quicker recovery, it may have higher complication rates. The use of gases like SF6 and C3F8 for anterior chamber tamponade is evolving, with conflicting findings on their efficacy in preventing graft detachment. Furthermore, IOL selection remains crucial, as hyperopic refractive surprises are common, and hydrophilic lenses should be avoided owing to the risk of opacification after EK. The combination of cataract surgery with EK has emerged as an effective treatment for patients with corneal endothelial diseases and cataract. Careful preoperative evaluation, appropriate IOL selection, and advances in surgical techniques contribute to better outcomes, although patient-specific factors must guide the choice between sequential and triple-EK procedures.

Corneal High-Order Aberrations in Fuchs Endothelial Corneal Dystrophy and Subclinical Corneal Edema.

High-order aberrations (HOAs) are known to be increased in corneas with Fuchs endothelial dystrophy (FECD) and are associated with visual impairment. This case series aimed to analyze whether tomographic changes in FECD affect the HOA in the early period of the disease. In this retrospective single-center case series, 144 eyes of 85 patients were included, of which 78 eyes of 47 patients with FECD with slit-lamp biomicroscopically visible guttae but no visible corneal edema served as the study-cohort. According to Sun et al, included eyes were divided into 2 groups: group 0 (n = 28; no subclinical corneal edema) and group 1 (n = 50; subclinical corneal edema). A total of 66 healthy eyes of 38 patients served as control group. Mean values and standard deviations were calculated for the root mean square (RMS), coma, trefoil and spherical aberrations (SA) of the cornea (C), the anterior surface (CF), and the posterior surface (CB). Statistically significant differences (P < 0.001) in the RMS HOA (group 0: 0.209 ± 0.044 μm, group 1: 0.372 ± 0.122 μm) and in coma (group 0: 0.082 ± 0.054 μm, group 1: 0.214 ± 0.101 μm) and SA (group 0: -0.130 ± 0.038 μm, group 1: -0.176 ± 0.074 μm) of the CB were found in eyes in group 1 versus those in group 0. There were no statistically significant differences in HOA between the control group and eyes in group 0. FECD eyes with subclinical corneal edema demonstrated significant increase in RMS, coma, and SA of the CB. Tomographic analysis, therefore, helps in visual impairment assessment, disease progression, and decision-making for early endothelial keratoplasty in patients with FECD.

Deep Learning Versus Corneal Tomography Features to Detect Subclinical Corneal Edema in Fuchs Endothelial Corneal Dystrophy

Purpose: To compare a deep learning model with corneal tomography features for detecting subclinical corneal edema in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: We trained a deep learning model to detect corneal edema on 379 optical coherence tomography B-scans of normal and edematous corneas. 51 eyes of 32 patients with FECD were analyzed and compared with 100 eyes of 50 normal patients. For each eye, the cornea was scanned on the same day using 2 modalities of the same swept-source optical coherence tomography device (Anterion): corneal tomography maps and 6 high-resolution radial B-scans. The 6 radial B-scans were analyzed using our model from which an en face map of edema was reconstructed. The location exhibiting the highest probability of edema was derived from that map. Two corneal surgeons assessed the tomography maps and labeled the location of the supposed highest edema. This location was compared with our model's en face map. Results: According to tomography features, 64.7% of eyes presented subclinical edema. Our model and tomography features agreed in 80% of cases for the presence or absence of subclinical edema. The average distance between the location of maximal edema determined by human experts on tomography maps and that derived from our model's en face map was 1.91 ± 1.15 mm. Our model detected superior peripheral edema in a majority of eyes. Conclusions: Despite being based on different approaches, both methods agreed in the detection of subclinical edema in most cases. The location of detected edema was very similar in both methods. In cases where both methods disagree, our approach provides new objective results that might help the surgeon in making a decision in difficult cases.

Differences in Guttae Ultramorphology in Relation to Visual Function in Fuchs Endothelial Corneal Dystrophy.

The purpose of this study was to investigate the differences in guttae ultramorphology and their relation to visual function in eyes with Fuchs endothelial corneal dystrophy (FECD). Thirty FECD eyes without ocular comorbidities were included. Visual functional parameters (best-corrected visual acuity with high-contrast and low-contrast letters and contrast sensitivity/LogCS) and corneal morphology measured with Scheimpflug tomography (Pentacam) were assessed. The surgically removed Descemet membranes were examined by light and transmission electron microscopy. Preoperative mean best-corrected visual acuity (logarithm of the minimum angle of resolution) was 0.52 ± 0.18, LogCS 0.96 ± 0.21 and central corneal thickness 640 ± 55 μm. All eyes had signs of subclinical corneal edema in Scheimpflug tomography; clinically visible corneal edema was present in 40% of eyes. Histological findings included a posterior fibrillar zone (PFZ) in 10 specimens (33%) and abnormal collagen depositions in Descemet membranes in 14 specimens (47%). Guttae buried within the PFZ were present only in eyes with clinically visible edema (n = 4, 13%). There was no difference in visual function results and tomography parameters between eyes with and without PFZ or between protruding guttae and guttae embedded in a PFZ, respectively. Guttae morphology and density were not correlated with visual functional parameters. Guttae buried in a PFZ occurred only in eyes with clinically manifest edema, and thereby, they are an ultramorphological sign for advanced FECD. Subclinical edema was present in all eyes and might be more relevant for quality of vision than guttae ultramorphology.

Scheimpflug Tomography as a Predictor of Corneal Edema After Phacoemulsification in Fuchs Endothelial Corneal Dystrophy.

To determine if Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict the occurrence of corneal edema following uneventful phacoemulsification surgery in Fuchs endothelial corneal dystrophy (FECD). Observational prospective case-control study. Fifty FECD eyes (50 patients) with visually significant cataract: 25 with subclinical corneal edema (SCE) versus 25 without SCE. Preoperatively, FECD was clinically assessed, and only patients devoid of clinical corneal edema were enrolled. Utilizing the Mayo Clinic classification for subclinical corneal edema (SCE), eligible FECD eyes were stratified based on Scheimpflug imaging pachymetry map and posterior elevation map characteristics, including loss of regular isopachs, displacement of the cornea's thinnest point, and the presence of posterior surface depression, into two groups: Group A representing FECD with SCE, and Group B: FECD without SCE. One week postoperatively, clinical and tomographic evaluation was performed. Regression analysis was conducted to evaluate predictors of corneal edema after uneventful phacoemulsification surgery in both groups. All patients were successfully imaged before and 1 week after surgery. Visual acuity was significantly improved in both groups (P < 0.001). No postoperative clinical edema was observed in Group B, while 23 (92%) had mild edema and 2 (8%) had moderate edema in Group A. Both groups showed a significant increase in postoperative central corneal thickness (CCT) and thinnest corneal thickness (TCT) (both P < 0.001). Compared to Group B, Group A showed a significant central flattening of the anterior corneal surface (P = 0.007 and P = 0.04 for K1 and K2 respectively), and a significant increase in the postoperative posterior surface depression. Multivariate analysis showed that 94% of postoperative corneal edema could be predicted by the presence of preoperative posterior surface depression (P = 0.04, ARR = 5.8 (1.89-35.7)). Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict corneal edema after uneventful phacoemulsification surgery in FECD with subclinical corneal edema.

Influence of Subclinical Corneal Edema on Contrast Sensitivity in Fuchs Endothelial Corneal Dystrophy.

The aim of this study was to compare visual function, with a focus on contrast sensitivity, between patients with Fuchs endothelial corneal dystrophy (FECD) with and without subclinical corneal edema. In this cross-sectional, observational, single-center study, 46 pseudophakic eyes of 31 patients with FECD were divided into 2 groups depending on the presence of subclinical corneal edema. All eyes presented with a Krachmer grade of 5 and no clinical corneal edema. The criteria for subclinical corneal edema were loss of regular isopachs, displacement of the thinnest point, and focal posterior surface depression in Scheimpflug tomography. If more than 1 criterion was present, subclinical corneal edema was diagnosed. The corrected distance visual acuity, contrast sensitivity (Pelli-Robson chart and CSV-1000 test with optional glare), and straylight were measured. The differences between both groups were analyzed using clustered Wilcoxon rank-sum tests. The corrected distance visual acuity and the contrast sensitivity, measured with a Pelli-Robson chart, were significantly inferior in eyes with subclinical corneal edema compared with eyes without subclinical edema ( P < 0.05). At all spatial frequencies, eyes with subclinical edema demonstrated lower contrast sensitivity with a statistically significantly reduction in total contrast sensitivity when tested with ( P = 0.005) and without ( P = 0.002) glare. The straylight did not significantly differ between both groups ( P > 0.05). The corrected distance visual acuity and contrast sensitivity were significantly reduced in FECD eyes with subclinical corneal edema compared with those with no subclinical edema. This decrease in visual quality may be considered when evaluating the need for surgical intervention at earlier stages of FECD.

The Impact of Severe COVID–19 on Corneal Endothelial Cells–Analysis of the In Vivo Noncontact Specular Microscopy

ABSTRACT Purpose This study aimed to investigate the effects of severe COVID-19 infection on the corneal endothelium via in vivo specular microscopy. Methods This was an observational, prospective, and controlled study including 56 eyes of 56 severe COVID-19 patients, compared to after-recovery and 56 eyes of 56 age- and gender-matched healthy controls. Results Endothelial cell density was lower in the active disease period compared to healthy controls (p = .001) and decreased even more after recovery (p < .0001). After recovery, the average cell area and coefficient of variation were higher compared to the active disease period (p < .0001 and p = .008, respectively) and the healthy controls (for both, p < .0001), whereas hexagonality was lower (p < .0001). Central corneal thickness increased in the active disease period compared to after recovery (p < .0001) and healthy controls (p = .002). Conclusions These results may be due to direct host-virus interaction or linked to immune dysregulation, subclinical corneal endotheliitis, or still yet a viral-mediated inflammation.

Refractive surprise of irregular astigmatism following cataract surgery in two patients with neglected subclinical corneal ectasia: two case reports

BackgroundCorneal ectatic diseases are a group of corneal disorder characterized by the steepening and thinning of the cornea. Older people are not a high-risk population for corneal ectatic diseases; due to the lack of typical preoperative topographic manifestations, there is a high possibility that corneal ectasia is undetected.Case presentationTwo patients with subclinical corneal ectasia and senile cataracts presented with irregular astigmatism after steep-axis incision during cataract surgery. The two cases presented in this case report are rare because both patients experienced tremendous changes in astigmatism after cataract surgery.ConclusionThis case report may shed some light on astigmatism-correcting steep-axis incisions in cataract surgeries.

Anterior Corneal High-order Aberrations in Fuchs' Endothelial Corneal Dystrophy Classified by Scheimpflug Tomography.

Visual acuity may be limited after endothelial keratoplasty in Fuchs' endothelial corneal dystrophy. This may be due to increased anterior high-order aberrations that persist after endothelial keratoplasty. It is not clear at what stage these aberrations begin. We aimed to evaluate how subclinical corneal edema affects anterior corneal high-order aberrations. We aimed to evaluate anterior corneal high-order aberrations according to the presence of subclinical corneal edema in Fuchs' endothelial corneal dystrophy using Scheimpflug topography. All the patients underwent corneal topography (Sirius Scheimpflug-Placido disc camera; CSO Ophthalmic, Scandicci, Italy). Fifty-two eyes of 31 patients with Fuchs' endothelial corneal dystrophy and 52 eyes of 35 patients without corneal problems were included. In addition, patients with Fuchs' endothelial corneal dystrophy were divided into two groups according to subclinical corneal edema as with Fuchs' endothelial corneal dystrophy-edema and Fuchs' endothelial corneal dystrophy-nonedema. Subclinical corneal edema was defined based on the presence of at least two of three findings of the loss of regular isopachs, displacement of the thinnest point of the cornea, and posterior depression. High-order aberrations were expressed as Zernike polynomials in the 4- and 6-mm optical zone. We found that subclinical corneal edema in Fuchs' endothelial corneal dystrophy caused a larger 4-mm trefoil II and a smaller 6-mm spherical aberration II measurements than the nonedema group. The 6-mm total high-order aberrations, 6-mm coma aberration, and 4- and 6-mm trefoil II aberration measurements were larger, and the 6-mm spherical aberration II was smaller in Fuchs' endothelial corneal dystrophy patients with edema compared with the healthy eyes. The presence of subclinical corneal edema in Fuchs' endothelial corneal dystrophy results in larger 4-mm trefoil II and smaller 6-mm spherical aberration II measurements. More patients with intermediate values are needed to evaluate the effect of these aberrations on visual acuity.

Determining subclinical edema in fuchs endothelial corneal dystrophy: Scheimpflug versus anterior segment‐optical coherence tomography

AbstractPurpose: To compare the capacity of anterior segment optical coherence tomography (AS‐OCT) and Scheimpflug camera in detecting subclinical corneal edema in patients with Fuchs endothelial corneal dystrophy (FECD).Methods: 177 eyes of 103 patients with FECD without obvious corneal edema were included and analysed in this single‐center prospective study (NCT03974230). Tomographic analyses were performed successively using Scheimpflug imaging (Pentacam HR, Oculus) and a swept‐source AS‐OCT (Casia SS‐1000 Tomey). All measurements were performed more than 4 hours after awaking to have a stabilized corneal thickness. The resulting images were analysed by two experienced independent observers. AS‐OCT and Scheimpflug images were analysed independently. The main outcome was the agreement between the ability of the two devices to detect subclinical corneal edema, assessed using inter‐device reliability measured by the Cohen kappa statistic. The criteria for subclinical corneal edema were as follows: the presence of irregular isopachs, displacement of the thinnest point of the cornea, and the presence of posterior surface depression.Results: The agreement between the two devices to detect subclinical corneal edema was high. The inter‐device reliability for loss of parallel isopachs, as measured by the Cohen kappa coefficient, was 0.75; for the displacement of the thinnest point of the cornea, it was 0.65; and for the focal posterior corneal surface depression, it was 0.53. The inter‐device reliability for the detection of subclinical corneal edema was 0.70. Subclinical corneal edema was detected in 77% of cases analysed with both devices.Conclusions: Subclinical corneal edema in patients with FECD can be detected by AS‐OCT as well as by Scheimpflug imaging. Both devices can facilitate surgical decision‐making when evaluating the risk of corneal edema after cataract surgery in eyes with FECD.

Detecting Subclinical Corneal Edema Using Corneal Thickness Mapping in Patients Presenting Fuchs Endothelial Corneal Dystrophy

To determine whether local corneal thickness changes observed with optical coherence tomography (OCT) can detect subclinical corneal edema in Fuchs endothelial corneal dystrophy (FECD). Retrospective cohort study. A series of patients presenting FECD who underwent cataract surgery alone (45 eyes) or with concomitant Descemet membrane endothelial keratoplasty (triple procedure; 117 eyes). The study reviewed medical records, collected the preoperative corneal thickness map and calculated the differences and ratio of corneal thickness measured at 5, 7, and 9 mm from the central corneal thickness. Area under the receiver operating characteristic curves (AUCs) were calculated and thresholds were selected to obtain a specificity of 90%. The median difference between 5- and 2-mm corneal thickness in the supra-nasal quadrant (∆5-2mmSN) was 38 µm (interquartile range 34-46) in the cataract group and 17 µm (2-38) in the triple procedure group (P < .001). The corneal thickness ratios of supra-nasal 5- to 2-mm (R5/2mmSN) and 7- to 2-mm (R7/2mmSN) were 1.07 (1.06-1.08) and 1.15 (1.13-1.17)] in the cataract group and 1.03 (1.00-1.06) and 1.09 (1.06-1.14) in the triple procedure group (P < .001). The probability of corneal edema was increased 7-fold with ∆5-2mm SN < 27 µm (AUC=0.76) and 9.4- and 7.4-fold with R5/2mmSN and R7/2mmSN < 1.045 (AUC=0.77) and 1.118 (AUC=0.76), respectively. Local changes in corneal thickness may be useful in detecting preclinical corneal edema, especially in patients with FECD undergoing cataract surgery.

Scheimpflug Versus Optical Coherence Tomography to Detect Subclinical Corneal Edema in Fuchs Endothelial Corneal Dystrophy.

The purpose of this research was to compare the ability of Scheimpflug and anterior segment optical coherence tomography (OCT) in detecting subclinical corneal edema in patients with Fuchs endothelial corneal dystrophy (FECD) without clinical corneal edema. In this single-center, consecutive case series, 47 eyes of 29 patients with FECD were analyzed. The main outcome measures were anterior/posterior keratometry and central/thinnest corneal thickness. The criteria for subclinical corneal edema were loss of regular isopachs, displacement of the thinnest point of the cornea, and presence of posterior surface depression. Tomographic analyses were performed using Scheimpflug imaging (Pentacam HR) and OCT (anterior segment swept-source optical coherence tomography). The measurement of the continuous variables revealed a significant difference between the 2 devices. The anterior curvature was steeper and the posterior curvature was flatter when measured with OCT ( P < 0.001). The OCT showed a lower central corneal thickness and thinnest corneal thickness ( P < 0.001). The agreement between both devices to detect subclinical corneal edema was high. The interdevice reliability for loss of parallel isopachs as measured by Cohen kappa coefficient was 0.84; for the displacement of the thinnest point of the cornea, it was 0.6, and for the focal posterior corneal surface depression, it was 0.62. Subclinical corneal edema was detected in 72.3% of the patients with both devices. In only 2 cases (4.3%), subclinical corneal edema was detected by one of the devices. Scheimpflug and OCT imaging were both able to detect tomographic patterns of subclinical corneal edema. Therefore, both devices can help decision-making, favoring early endothelial keratoplasty in symptomatic patients with FECD without clinical corneal edema.

A Risk Prediction Model for Endothelial Keratoplasty After Uncomplicated Cataract Surgery in Fuchs Endothelial Corneal Dystrophy

To develop a risk prediction model for endothelial keratoplasty (EK) after uncomplicated cataract surgery in Fuchs endothelial corneal dystrophy (FECD) using Scheimpflug imaging. Prospective, observational cohort study. The study was conducted at the Ramón y Cajal University Hospital (Madrid, Spain) on 127 eyes from 93 consecutive patients with vision loss, FECD, and cataracts. We assessed the corneas using Scheimpflug imaging pachymetry and elevation maps for loss of regular isopachs, displacement of the thinnest point, and posterior surface depression according to the Mayo Clinic subclinical corneal edema classification. We also recorded other preoperative data. Primary Endpoints: The primary endpoint was the need for EK after uncomplicated phacoemulsification within 2 years (median duration, 18 months). We calculated the risk using hazard ratios and the Kaplan-Meier cumulative incidence risk. Forty-four participants required EK, and those eyes with 1, 2, or all 3 tomographic features had a hazard risk of 21.8, 57.2, and 76.5, respectively (P < .005), compared with those eyes with normal tomographic patterns. The best predictive model was based on the number of tomographic features simultaneously present in an eye and the central corneal thickness (CCT) at the pupillary center. We aimed to develop a risk score from 0 to 8. The cumulative risk for EK ranged from virtually 0 for risk scores <4 to almost 100% for those with a score of 8. The combination of CCT values and tomographic features can be employed to make valid predictions of the risk of requiring EK after phacoemulsification.

Modeling Changes in Corneal Parameters With Age: Implications for Corneal Disease Detection

To apply computational methods to model normal age-related changes in corneal parameters and to establish their association with demographic factors, thereby providing a framework for improved detection of subclinical corneal ectasia (SCE). Cross-sectional study. One hundred seventeen healthy participants were enrolled from Centre for Eye Health (Sydney, Australia). Corneal thickness (CT), front surface sagittal curvature (FSSC), and back surface sagittal curvature (BSSC) measurements were extracted from 57 corneal locations from 1 eye per participant using the Pentacam HR. Cluster analyses were performed to identify locations demonstrating similar variations with age. Age-related changes were modeled using polynomial regression with sliding window methods, and model accuracy was verified with Bland-Altman comparisons. Pearson correlations were applied to examine the impacts of demographic factors. Concentric cluster patterns were observed for CT and FSSC but not for BSSC. Sliding window analyses were best fit with quartic and cubic regression models for CT and FSSC/BSSC, respectively. CT and FSSC sliding window models had narrower 95% limits of agreement compared with decade-based models (0.015mm vs 0.017mm and 0.14mm vs 0.27mm, respectively), but were wider for BSSC than decade-based models (0.73mm vs 0.54mm). Significant correlations were observed between CT and astigmatism (P=.02-.049) and FSSC and BSSC and gender (P=<.001-.049). The developed models robustly described aging variations in CT and FSSC; however, other mechanisms appear to contribute to variations in BSSC. These findings and the identified correlations provide a framework that can be applied to future model development and establishment of normal databases to facilitate SCE detection.

Detection of Subclinical Corneal Ectasia Using Corneal Tomographic and Biomechanical Assessments in a Japanese Population.

To test the detection of subclinical corneal ectasia using integrated Scheimpflug tomography and biomechanical assessment in a Japanese population. This prospective, case-control study included 23 patients with very asymmetric ectasia (VAE) and 70 normal controls. Patients with VAE had defined clinical ectasia in one eye and a fellow eye with normal topography (VAE-NT). Objective topography for confirming normal topography in VAE-NT cases included having 0% similarity and 0% severity derived from Placido-disk based topography. Scheimpflug-based corneal tomography and corneal biomechanical assessment were performed. The Belin/Ambrósio Enhanced Ectasia Deviation index (BAD-D), Corvis Biomechanical Index (CBI), and Tomographic Biomechanical Index (TBI) were compared and their discriminating ability for detecting ectasia was assessed. For differentiating normal and VAE-NT eyes, the areas under the receiver operating curve for the BAD-D, CBI, and TBI were 0.668, 0.660, and 0.751, respectively. The TBI cut-off of 0.259 provided 52.17% sensitivity and 88.57% specificity. Fourteen VAE-NT cases (60.9%) were abnormal in at least one of the criteria of the BAD-D > 1.60 (39.1%), CBI > 0.5 (26.1%), or TBI > 0.29 (43.5%). Conversely, nine VAE-NT cases (39.1%) exhibited normal values for the BAD-D, CBI, and TBI. In the current study, 40% of VAE-NT eyes were classified as normal by the BAD-D, CBI, and TBI. Although some of these cases may truly represent unilateral ectasia, further advances are needed to enhance ectasia detection and characterize the susceptibility for ectasia progression. [J Refract Surg. 2019;35(6):383-390.].

Quantitative evaluation of corneal epithelial edema after cataract surgery using corneal densitometry: a prospective study

PurposeThe optical density of the cornea can be evaluated quantitatively by “densitometry” using a rotating Scheimpflug camera. Densitometry allows evaluation of corneal opacity in the anterior segment of the eye by quantitative measurement of scattering light. In the present investigation, we evaluate quantitatively minimal subclinical corneal edema after cataract surgery using densitometry.MethodsFifty four eyes of 34 patients who underwent cataract surgery were enrolled. Measurement of corneal density was performed using Pentacam® before and on days 1, 3 and 7 after surgery.ResultsDensitometry scores increased from 18.12 ± 1.76 before cataract surgery to 21.03 ± 3.84 on day 1 (P < 0.001) and 19.90 ± 2.46 on day 3 (P = 0.018), but recovered to 19.44 ± 1.58 on day 7 (P = 0.131). Total corneal thickness was 549.1 ± 32.7 μm before surgery and increased to 582.7 ± 46.3 μm on day 1 (P = 0.001), but recovered to 566.4 ± 29.7 μm on day 3 (P = 0.097). Densitometry reading correlated positively with corneal thickness (correlation coefficient = 0.13, P = 0.003).ConclusionsDensitometry is useful to detect corneal edema that is not detectable by slit-lamp examination.

Determining Subclinical Edema in Fuchs Endothelial Corneal Dystrophy: Revised Classification using Scheimpflug Tomography for Preoperative Assessment

To determine if Scheimpflug tomography can identify subclinical corneal edema in Fuchs endothelial corneal dystrophy (FECD), and to recommend a new classification of FECD for clinical practice and research. Cross-sectional study with follow-up of outcomes. Ninety-three eyes from 57 subjects with a range of severity of FECD and 74 eyes from 40 subjects with normal corneas. Corneas were clinically assessed for FECD and corneal edema by using slit-lamp biomicroscopy, and categorized as having clinically definite edema (obvious visible edema), being suspicious for subclinical edema (possible corneal thickening without obvious edema on slit-lamp examination), or not having edema (no clinical suspicion of edema). Tomographic pachymetry and elevation maps derived from Scheimpflug images were evaluated by 3 masked observers for specific features believed to be consistent with corneal edema. FECD clinical disease course and outcomes were reviewed from the time of Scheimpflug image acquisition to the last available follow-up. Presence of tomographic features: (1) loss of parallel isopachs, (2) displacement of the thinnest point of the cornea, and (3) focal posterior corneal surface depression. Clinical outcomes included the change in central corneal thickness (CCT) and vision after endothelial keratoplasty (EK). The 3 specific tomographic features were all present in all FECD corneas with clinically definite edema (n= 15), in ≥81% of FECD corneas suspicious for subclinical edema (n= 16), in ≤42% of FECD corneas deemed not to have edema (n= 62), and in ≤5% of normal corneas (n= 74). Corneas suspicious for subclinical edema that subsequently underwent EK (n= 9) all had at least 2 of the tomographic features present before EK, and improvement in vision, CCT, and tomographic features after EK confirmed the presence of subclinical edema preoperatively. Subclinical corneal edema in FECD can be detected by Scheimpflug tomography. We recommend classifying FECD corneas as having clinically definite edema (based on slit-lamp examination), subclinical edema (based on tomographic features without clinically definite edema), or no edema (no tomographic or slit-lamp features of edema). This classification is independent of CCT and should be considered when evaluating FECD eyes for cataract surgery or EK.

Confocal Microscopic Analysis of a Rabbit Eye Model of High-Incidence Recurrent Herpes Stromal Keratitis.

Using CJLAT, a chimeric herpes simplex virus (HSV-1) that produces a high incidence of herpes stromal keratitis (HSK) in latently infected rabbits, and in vivo confocal microscopy (CM), we characterized the cellular events that precede the development of HSK. Thirty days after infection, in vivo CM was performed daily for 10 days and then weekly for up to 80 days after infection. We detected 3 types of subclinical corneal lesions before HSK was clinically apparent: (1) small epithelial erosions; (2) regenerating epithelium overlying small cell infiltrates within the basal epithelial cell layer; and (3) dendritic-like cells within the basal epithelial layer overlying stromal foci containing infiltrating cells. Sequential in vivo CM observations suggested that subclinical foci resolved over time but were larger and more abundant with CJLAT than with wild-type HSV-1 McKrae. Active HSK was observed only with CJLAT and was initially associated with a large epithelial lesion overlying stromal immune cell infiltrates. These results suggest that replication in the cornea of reactivated virus from the trigeminal ganglia produces epithelial lesions, which recruit immune cell infiltrates into the basal epithelial layer and anterior stroma. The virus is usually cleared rapidly eliminating viral antigens before the arrival of the immune cells, which disperse. However, if the virus is not cleared rapidly, or if an additional reactivation results in an additional round of virus at the same site before the immune cells disperse, then the immune cells are stimulated and may induce an immunopathological response leading to the development of HSK.

Clinical and ultrastructural characteristics of graft failure in DMEK: 1-year results after repeat DMEK.

To evaluate the role of preexisting corneal pathology on the outcome of Descemet membrane endothelial keratoplasty (DMEK), and also to evaluate the long-term outcome of repeat DMEK for graft failure after primary DMEK. Eighteen patients undergoing repeat DMEK after failed DMEK were enrolled; 9 of 18 patients had successful primary DMEK on the fellow eye. Evaluations included preoperative anterior chamber depth, intraoperative degree of difficulty, transmission electron microscopy images (n = 14), best-corrected visual acuity (BCVA), endothelial cell density, central corneal thickness, corneal volume, and patient satisfaction. Surgeries that led to graft failure had a higher intraoperative degree of difficulty compared with successful surgeries (P = 0.002). Eight of 14 failed grafts showed ultrastructural abnormalities, that is, inclusions or deposits of abnormal fibrillar material in Descemet membrane, indicating endothelial dysfunction before transplantation. BCVA on day 10 after surgery was worse in eyes with graft failure compared with successful DMEK (P = 0.008). Median BCVA (logarithm of the minimum angle of resolution) improved from 0.5 before DMEK and 1.9 before repeat DMEK to 0.3 at 1-year follow-up (P = 0.011). One year after repeat DMEK, endothelial cell density (cells/mm2) of donor corneas decreased from 2501 ± 264 to 1373 ± 270 (P < 0.001), central corneal thickness (µm) decreased from 807 ± 160 to 576 ± 178 (P = 0.002), and corneal volume (mm3) decreased from 84.1 ± 13.0 to 64.4 ± 12.5 (P = 0.002). Patient satisfaction showed no difference between primary and repeat DMEK. A preexisting subclinical corneal endothelial dysfunction may contribute to primary DMEK failure. Repeat DMEK can be performed safely with good long-term outcome.

Relevancy of corneal biomechanical in glaucoma

Case report of a patient, with a thick cornea, for Fuchs dystrophy in its early stages, yet with preserved corneal transparency (subclinical corneal edema), associated with normal intraocular pressure (IOP) by Goldman applanation tonometry (GAT), which was however, the diagnosis of primary open-angle glaucoma on the basis of structural changes of the optic nerve. The tomographic study showed a pattern of spatial pachymetry compatible with subclinical edema. The corneal biomechanical study with ORA (Ocular Response Analyzer, Reichert ®) associated with [...]