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18 pages, 1823 KB  
Article
A Novel Non-Planar Bioprinting Methodology for Enhanced Surface Fidelity of the Cornea
by Laura Pérez Sánchez, Hodei Gómez-Fernández, Maialen Zelaia Amilibia, Maria Basañez Elorrieta, Eva Larra Mateos, Alessandro Scandurra, José Luis Pedraz Muñoz, Denis Scaini and Camilo Cortés
Bioengineering 2026, 13(6), 682; https://doi.org/10.3390/bioengineering13060682 (registering DOI) - 12 Jun 2026
Viewed by 197
Abstract
Traditional 3D bioprinting of corneal constructs relies on planar slicing, which often results in a significant stairstep effect and the loss of anatomical curvature. Curvilinear layering has emerged as a promising alternative to address these limitations. The presented methodology, based on non-planar layer [...] Read more.
Traditional 3D bioprinting of corneal constructs relies on planar slicing, which often results in a significant stairstep effect and the loss of anatomical curvature. Curvilinear layering has emerged as a promising alternative to address these limitations. The presented methodology, based on non-planar layer integration, ensures a smoother surface finish. The model’s surface is identified via vertex normals and reconstructed using the Poisson method. Finally, surface parametrization is applied to generate spatially curved trajectories. To validate the algorithm, corneal constructs were printed using a planar and the proposed non-planar approach. Quantitative evaluation of micro-Computed Tomography data revealed that the non-planar approach achieved significantly higher morphological fidelity, successfully replicating the intended parabolic profile of the human cornea. Furthermore, the non-planar constructs demonstrated adequate functional performance, characterized by high optical transparency. Thereby, the feasibility of printing non-planar layers using the proposed novel approach is successfully demonstrated. Furthermore, the comparative analysis confirms the method’s potential for corneal biofabrication when compared to traditional planar methods. Full article
(This article belongs to the Special Issue Bioengineering and the Eye—3rd Edition)
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15 pages, 3524 KB  
Article
Biomechanical and Tomographic Outcomes in Pediatric Keratoconus Treated with Conventional Epithelium-Off Corneal Collagen Cross-Linking
by Radu-Nicolae Pop, Patricia Ariadna Nicula, Cristina Ariadna Nicula, Dorin Vasile Nicula and Bianca Pop
Medicina 2026, 62(6), 1145; https://doi.org/10.3390/medicina62061145 - 12 Jun 2026
Viewed by 140
Abstract
Background and Objectives: Pediatric keratoconus may progress rapidly, and treatment decisions are often made before prolonged observation is possible. This study evaluated 24-month visual, tomographic, pachymetric, and biomechanical outcomes after conventional epithelium-off corneal collagen cross-linking (CXL) using Pentacam tomography and Corvis ST [...] Read more.
Background and Objectives: Pediatric keratoconus may progress rapidly, and treatment decisions are often made before prolonged observation is possible. This study evaluated 24-month visual, tomographic, pachymetric, and biomechanical outcomes after conventional epithelium-off corneal collagen cross-linking (CXL) using Pentacam tomography and Corvis ST dynamic Scheimpflug analysis. Materials and Methods: This single-center observational longitudinal cohort included 28 eyes of 23 patients aged 13–18 years treated at the OCULENS Clinic, Cluj-Napoca, Romania, between 2019 and 2023. Because the study had no untreated or alternative-treatment control group, postoperative changes were interpreted as associations after CXL rather than as proof of causality. Baseline, 6-, 12-, and 24-month values were analyzed for UCVA, BCVA, Kmax, thinnest pachymetry, SP-A1, deformation amplitude (DA), first and second applanation times (A1T and A2T), highest concavity (HC) radius, and BAD-D. Repeated-measures ANOVA was used after assessment of within-eye difference normality; findings were interpreted cautiously because the analysis was eye-based, the cohort was small, and multiple outcomes were examined. Results: UCVA improved from 0.53 ± 0.16 to 0.44 ± 0.16 logMAR and BCVA from 0.31 ± 0.11 to 0.25 ± 0.11 logMAR (both p < 0.001). Mean Kmax decreased modestly from 54.36 ± 3.11 D to 53.41 ± 2.79 D, while SP-A1 increased from 84.69 ± 4.75 to 97.39 ± 5.11 (both p < 0.001). Thinnest pachymetry showed early postoperative thinning followed by partial recovery by 24 months. DA decreased, A1T increased, A2T decreased, HC radius increased, and BAD-D decreased significantly. Kmax and SP-A1 were inversely correlated at all visits (r = −0.714 to −0.773; all p < 0.001), but these correlations were considered exploratory. Post-24-month retreatment and keratoplasty-related events were recorded descriptively and were not included in the formal 24-month model. Conclusions: Within the prespecified 24-month analytic window, conventional epithelium-off CXL was associated with stabilization, modest visual and tomographic improvement, and a concordant biomechanical stiffening signal. The results should be interpreted as cautious observational findings rather than definitive evidence of long-term stability, because of the small sample, eye-level analysis, absence of a control group, limited follow-up, and lack of formal repeatability testing. Full article
(This article belongs to the Section Ophthalmology)
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12 pages, 598 KB  
Article
Beyond the Cornea: Early Changes in Scleral, Iris, and Corneal Parameters After Corneal Collagen Cross-Linking
by Tunahan Akyol, Osman Parca, Emine Seker Un, Ibrahim Toprak and Gokhan Pekel
J. Clin. Med. 2026, 15(12), 4428; https://doi.org/10.3390/jcm15124428 - 8 Jun 2026
Viewed by 150
Abstract
Background/Objectives: To evaluate early postoperative changes in scleral and iris thicknesses together with corneal layer thicknesses and tomographic parameters following corneal collagen cross-linking (CXL) in eyes with progressive keratoconus. Methods: This retrospective study included 94 eyes of 94 patients with progressive keratoconus who [...] Read more.
Background/Objectives: To evaluate early postoperative changes in scleral and iris thicknesses together with corneal layer thicknesses and tomographic parameters following corneal collagen cross-linking (CXL) in eyes with progressive keratoconus. Methods: This retrospective study included 94 eyes of 94 patients with progressive keratoconus who underwent standard epithelium-off CXL using the Dresden protocol. Corneal tomography (Pentacam) and anterior segment optical coherence tomography (AS-OCT) measurements were obtained preoperatively and at the early postoperative follow-up (3 months ± 2 weeks). Thickness measurements of the tear film, corneal epithelium, Bowman layer, stroma, Descemet–endothelium complex, sclera (1–3 mm from the limbus), and iris (1–2 mm from the pupillary margin) were analyzed. Pre- and post-CXL values were compared using paired statistical tests, and effect sizes were calculated. Results: In the early postoperative period, scleral thickness showed a significant increase at all measured distances from the limbus, with medium effect sizes, while iris thickness demonstrated a significant decrease at all measurement points with large effect sizes (p < 0.001). Tear film, epithelial, and stromal thicknesses decreased significantly after CXL, whereas Bowman layer and Descemet–endothelium complex thicknesses remained unchanged. Pachymetric measurements revealed significant thinning at the pupil center, corneal apex, and thinnest point. No significant changes were observed in Kmax or anterior chamber depth, indicating stabilization rather than progression in the early postoperative period. Conclusions: Corneal collagen cross-linking was associated with measurable early structural changes in corneal layers and extra-corneal anterior segment tissues during the postoperative period. The observed increase in scleral thickness and decrease in iris thickness suggest that structural alterations may occur in extra-corneal anterior segment tissues following CXL. These findings support the concept that CXL influences anterior segment biomechanics in a tissue-specific manner and that extra-corneal parameters may serve as complementary markers for early postoperative assessment. Full article
(This article belongs to the Special Issue Diagnosis and Management of Corneal Diseases)
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16 pages, 2821 KB  
Article
Deep Learning for the Detection of Corneal Perforation on Anterior-Segment Optical Coherence Tomography in Microbial Keratitis
by Lucia H. Rhode, Kamini N. Reddy, Folahan Ibukun, Subeesh Kuyyadiyil, Elesh Jain, Gautam S. Parmar, Rama Chellappa and Nakul S. Shekhawat
Bioengineering 2026, 13(6), 649; https://doi.org/10.3390/bioengineering13060649 - 30 May 2026
Viewed by 411
Abstract
Purpose: The purpose of this study was to develop and evaluate deep learning models for automated detection of corneal perforation in microbial keratitis using anterior segment optical coherence tomography (ASOCT) images. Methods: We enrolled 150 patients with microbiologically confirmed keratitis. Contralateral [...] Read more.
Purpose: The purpose of this study was to develop and evaluate deep learning models for automated detection of corneal perforation in microbial keratitis using anterior segment optical coherence tomography (ASOCT) images. Methods: We enrolled 150 patients with microbiologically confirmed keratitis. Contralateral healthy eyes served as controls. Ground-truth labels for perforation were established following consensus grading by two masked ophthalmologist graders. A ResNet-34 backbone was used to encode six radial ASOCT scans of an eye independently and mean-pooled into a single eye-level prediction for classification of the presence or absence of corneal perforation. Four model variants were trained. Models differed in the inclusion of healthy controls and stochastic masking of non-corneal anterior segment anatomy during training. All four model variants were evaluated with 5-fold patient-level cross-validation, and the recommended model was chosen on pooled out-of-fold (OOF) test performance. Results: All four model variants achieved high discrimination, with pooled OOF test receiver operating characteristic area under the curve (ROC AUC) between 0.924 and 0.971. The best-performing model (Model 3), which did not include healthy controls or stochastic masking of the inferior image portion during training, achieved an ROC AUC of 0.971 (95% CI, 0.943–0.993), average precision (AP) of 0.863 (95% CI, 0.713–0.963), sensitivity of 0.875 (95% CI, 0.727–1.000), specificity of 0.913 (95% CI, 0.858–0.959), and F1 of 0.750 (95% CI, 0.609–0.870) at the validation-derived Youden threshold. The addition of healthy contralateral eyes to the training set did not improve pooled OOF test metrics, and stochastic inferior blackout produced opposing effects in the two training cohort settings. In the infected-only cohort, it reduced both ROC AUC and AP, whereas in the +healthy cohort, it increased ROC AUC and substantially increased AP. Conclusions: Deep learning models achieved high diagnostic accuracy for detecting corneal perforation on ASOCT imaging in eyes with microbial keratitis. These findings support the potential role of automated ASOCT analysis as a clinical decision-support tool for identifying this vision-threatening complication. Full article
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14 pages, 288 KB  
Article
Relationship Between Scheimpflug-Based Ocular Biomechanics and Myopia Progression in Adolescents
by Pedro M. L. Baptista, João H. Marques, André Ferreira, Gabriel Santos, Paulo Sousa, Ricardo Parreira, Renato Ambrósio, Pedro M. A. M. Menéres and João N. M. Beirão
Bioengineering 2026, 13(6), 615; https://doi.org/10.3390/bioengineering13060615 - 25 May 2026
Viewed by 540
Abstract
Background/Objectives: To describe the progression of axial and segmental ocular biometric lengths and refractive status in adolescents and study independent associations between these changes and baseline ocular biomechanics. Methods: Prospective cohort of 126 eyes from 63 individuals followed for 2.5 years. Data from [...] Read more.
Background/Objectives: To describe the progression of axial and segmental ocular biometric lengths and refractive status in adolescents and study independent associations between these changes and baseline ocular biomechanics. Methods: Prospective cohort of 126 eyes from 63 individuals followed for 2.5 years. Data from general health and lifestyle were collected through a validated questionnaire. Data from ocular biometry (IOL MASTER 700®), objective refraction, and ocular biomechanics (Corvis ST®) were collected at baseline and the end of follow-up timepoints. Biomechanical parameters were correlated with the variation in axial length (d_AL), vitreous cavity length (d_VCL), and spherical equivalent (d_SE). Multivariable linear regression models (one eye randomly assigned) adjusted for age, SE, and AL were developed to identify independent associations between baseline biomechanics and d_AL, d_VCL, and d_SE. Results: The cohort of the present work had a mean age of 14.1 ± 2.6 years at baseline. Variations of 0.122 ± 0.17 mm, 0.092 ± 0.17 mm, and −0.32 ± 0.9 D were found in AL, VCL, and SE at follow-up, respectively. Within the multivariable regression models, the biomechanical parameters found to be independently associated with d_AL (model 1), d_VCL (model 2), and d_SE (model 3) were as follows: Model 1—Biomechanically corrected IOP (bIOP), Integrated Radius (IR), and A2 Deflection Area (A2DArea); Model 2—bIOP, IR, and A2DArea; and Model 3—IR and WholeEyeMovementMAxTime (MaxWEMT). Conclusions: The study of ocular biomechanical behavior may play a pivotal role in the risk assessment of ocular elongation and myopic progression. This work found independent associations between ocular biomechanical behavior at baseline and axial and segmental ocular elongation and refractive myopization, mainly including bIOP, IR, and MaxWEMT. Full article
(This article belongs to the Special Issue Bioengineering and the Eye—3rd Edition)
15 pages, 15276 KB  
Case Report
Masked Corneal Opacity in Bullous Keratopathy: The Impact of Epithelial Pathology on Surgical Decision-Making—A Case Report
by Wojciech Luboń, Łukasz Drzyzga, Wojciech Rokicki and Dorota Wyględowska-Promieńska
J. Clin. Med. 2026, 15(11), 4059; https://doi.org/10.3390/jcm15114059 - 24 May 2026
Viewed by 187
Abstract
Bullous keratopathy may lead to severe corneal opacity and impaired visualization of anterior segment structures, complicating surgical qualification for endothelial keratoplasty (EK). We report the case of a 67-year-old male with pseudophakic bullous keratopathy and Fuchs endothelial dystrophy presenting with clinically complete corneal [...] Read more.
Bullous keratopathy may lead to severe corneal opacity and impaired visualization of anterior segment structures, complicating surgical qualification for endothelial keratoplasty (EK). We report the case of a 67-year-old male with pseudophakic bullous keratopathy and Fuchs endothelial dystrophy presenting with clinically complete corneal opacity and visual acuity limited to hand motion. Slit-lamp examination and anterior segment optical coherence tomography demonstrated marked epithelial remodeling with a dense plaque-like surface lesion obscuring deeper corneal structures. A staged intraoperative approach was undertaken. Following mechanical epithelial debridement, partial restoration of corneal transparency allowed for an intraoperative reassessment of stromal clarity and subsequent Descemet Stripping Automated Endothelial Keratoplasty (DSAEK). Histopathological examination demonstrated reactive epithelial thickening with associated subepithelial fibrosis consistent with chronic bullous keratopathy. Postoperatively, corneal transparency was restored and best-corrected visual acuity improved to 0.7 Snellen (0.15 logMAR), remaining stable during follow-up without graft-related complications or recurrent epithelial abnormalities. This case highlights the importance of considering epithelial contributions to apparent corneal opacity in advanced bullous keratopathy and suggests that staged intraoperative reassessment may support individualized surgical decision-making in selected patients with inconclusive preoperative evaluation. Full article
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4 pages, 2614 KB  
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Bilateral Lipid Keratopathy Treated with Staged Penetrating Keratoplasty: Restoration of Corneal Transparency and Visual Function
by Wojciech Luboń and Mariola Dorecka
Diagnostics 2026, 16(10), 1551; https://doi.org/10.3390/diagnostics16101551 - 20 May 2026
Viewed by 189
Abstract
Lipid keratopathy is an uncommon corneal disorder characterized by stromal lipid deposition that may cause progressive corneal opacity and visual impairment. We report a case of advanced bilateral lipid keratopathy with severe visual-axis involvement. At presentation, best-corrected visual acuity (BCVA) was counting fingers [...] Read more.
Lipid keratopathy is an uncommon corneal disorder characterized by stromal lipid deposition that may cause progressive corneal opacity and visual impairment. We report a case of advanced bilateral lipid keratopathy with severe visual-axis involvement. At presentation, best-corrected visual acuity (BCVA) was counting fingers in the right eye and 0.1 Snellen (1.0 logMAR) in the left eye. Slit-lamp examination and anterior segment optical coherence tomography (AS-OCT) demonstrated dense stromal lipid deposits involving the visual axis in both eyes. The patient underwent staged bilateral penetrating keratoplasty, with procedures performed three months apart. Postoperatively, corneal transparency improved in both eyes. At 6 months, BCVA was 0.5 Snellen (0.3 logMAR) in the right eye and 0.7 Snellen (0.15 logMAR) in the left eye. Residual visual limitation was attributed mainly to coexisting cataract, and sequential cataract surgery was planned. Together, the clinical photographs and AS-OCT scans illustrate an uncommon presentation of visually disabling bilateral lipid keratopathy, characterized by dense central stromal lipid deposition involving both visual axes and profound preoperative visual loss. The case is clinically noteworthy because it combines severe bilateral disease, close clinical–tomographic correlation, and sequential penetrating keratoplasty performed as a staged visual rehabilitation strategy, resulting in restoration of graft clarity and meaningful visual improvement during postoperative follow-up. Full article
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16 pages, 4460 KB  
Article
Corneal Remodeling After DMEK in Fuchs Endothelial Dystrophy Patients: Quantitative and Qualitative Changes
by Ana Maria Arghirescu, Alina-Gabriela Gheorghe, Maria Cristina Marinescu, Dana-Margareta-Cornelia Dascalescu, Vasile Potop, Andreea-Gabriela Schmitzer, Liliana Mary Voinea, Farah Constantin and Radu Constantin Ciuluvica
Life 2026, 16(5), 805; https://doi.org/10.3390/life16050805 - 12 May 2026
Viewed by 275
Abstract
Background/Objectives: Fuchs endothelial corneal dystrophy (FECD) affects not only the corneal endothelium and Descemet membrane, but also the corneal thickness, shape, and optical quality. This study aimed to evaluate the quantitative and qualitative corneal changes after a Descemet membrane endothelial keratoplasty (DMEK) [...] Read more.
Background/Objectives: Fuchs endothelial corneal dystrophy (FECD) affects not only the corneal endothelium and Descemet membrane, but also the corneal thickness, shape, and optical quality. This study aimed to evaluate the quantitative and qualitative corneal changes after a Descemet membrane endothelial keratoplasty (DMEK) in patients with FECD and to compare the postoperative remodeling between eyes with subclinical corneal edema (F-SCE) and those with clinically evident corneal edema (F-CE). Methods: This retrospective observational study included 48 eyes of 40 patients with FECD who underwent DMEK between April 2023 and October 2025. The following parameters were assessed preoperatively and at 6 months postoperatively: central corneal thickness (CCT), mean pupillary power (MPP), anterior and posterior corneal astigmatism, total corneal higher-order aberrations (HOAs), anterior and posterior optical path difference (OPD), point spread function (PSF), anterior and posterior corneal surface regularity (RMS/A), and Gullstrand anterior/posterior (A/P) and posterior/anterior (P/A) ratios. The corneal data was obtained using a CSO MS-39 (Costruzione Strumenti Oftalmici, Firenze, Italy). Results: In the F-SCE subgroup, significant postoperative improvement was observed in the CCT (Δ = −84.6 ± 48.1 µm, p < 0.001), MPP (Δ = −1.010 ± 2.183, p < 0.001), posterior corneal regularity (posterior RMS/A) (Δ = −0.117 ± 0.229, p = 0.004), and both Gullstrand ratios (A/P: Δ = +0.111 ± 0.089, p < 0.001; P/A: Δ = −0.078 ± 0.064, p < 0.001). No significant change was detected in the anterior corneal regularity, anterior or posterior astigmatic metrics, total corneal higher-order aberrations, or PSF. In the F-CE subgroup, the postoperative response was greater, with significant improvement in the BCVA, CCT, thinnest corneal point, MPP, anterior and posterior corneal astigmatism, cylinder, total corneal HOAs, anterior and posterior corneal HOAs, PSF, anterior and posterior corneal regularity, and both Gullstrand ratios. Compared with the F-SCE eyes, the F-CE eyes showed significantly greater postoperative change in most structural and optical parameters, although most 6-month postoperative values were no longer significantly different between groups. Conclusions: DMEK induced significant corneal remodeling in both subclinical and clinically evident FECD. The eyes with subclinical edema demonstrated meaningful recovery in visual acuity, pachymetry, and posterior corneal regularity, supporting the presence of functional corneal impairment before a clinically visible edema. The eyes with clinically evident edema showed a broader and greater postoperative response, while the final postoperative values largely converged between groups. Full article
(This article belongs to the Special Issue Innovations in Diagnosis and Treatment of Ophthalmic Diseases)
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17 pages, 307 KB  
Review
Performance Comparison of Smartphone-Based Portable Slit Lamp Microscopes: A Narrative Review of Medical Devices Applicable to Telemedicine in Ophthalmology
by Eisuke Shimizu, Ryota Yokoiwa and Shintaro Nakayama
Appl. Sci. 2026, 16(9), 4448; https://doi.org/10.3390/app16094448 - 1 May 2026
Viewed by 464
Abstract
Smartphone-based portable slit lamp microscopes are increasingly used as low-cost tools for anterior segment imaging in teleophthalmology, yet the literature combines heterogeneous study designs, comparator standards, and deployment contexts. Because the evidence base spans engineering reports, basic science, clinical validation studies, implementation research, [...] Read more.
Smartphone-based portable slit lamp microscopes are increasingly used as low-cost tools for anterior segment imaging in teleophthalmology, yet the literature combines heterogeneous study designs, comparator standards, and deployment contexts. Because the evidence base spans engineering reports, basic science, clinical validation studies, implementation research, and case-based telemedicine, we structured a narrative review rather than a pooled meta-analysis. We searched PubMed/MEDLINE, Embase, Scopus, Web of Science, Google Scholar, Cochrane Library, ScienceDirect, and DOAJ for literature available on or before 28 February 2026, supplemented by manual reference list screening and targeted retrieval of relevant technical standards. Peer-reviewed English original studies formed the core evidence base; contextual non-English and gray literature sources were retained only when explicitly labeled as non-core. To improve interpretability, the results were grouped by synthesis domain, clinical task, comparator standard, telemedicine scenario, and artificial intelligence (AI) dataset/validation characteristics. The highest-confidence evidence concerned nuclear cataract grading, tear film breakup time and corneal staining assessment, anterior chamber depth screening, tear meniscus height measurement, allergic conjunctival grading, and selected corneal disorders. Agreement with conventional slit lamp examination or anterior segment optical coherence tomography was generally moderate to high within task-specific comparisons, and telemedicine deployment was feasible for screening, follow-up, remote consultation, emergency triage, house visits, and outreach. However, illumination reporting remains inconsistent, explicit ISO-aligned dosimetry is sparse, and most AI studies remain retrospective, single-center, and device family-specific. Current evidence, therefore, supports smartphone-based portable slit lamp microscopes primarily as adjunctive teleophthalmology tools rather than replacements for comprehensive in-clinic microscopy. The synthesis clarifies where conclusions are supported by comparative validation data, where they remain exploratory, and which methodological gaps should be prioritized in future multicenter studies. Full article
5 pages, 1592 KB  
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Multiplanar AS-OCT Detection of Clinically Occult Posterior Gas Bubble Dislocation After DSAEK
by Wojciech Luboń, Małgorzata Luboń and Mariola Dorecka
Diagnostics 2026, 16(9), 1267; https://doi.org/10.3390/diagnostics16091267 - 23 Apr 2026
Viewed by 273
Abstract
Descemet stripping automated endothelial keratoplasty (DSAEK) is a well-established surgical technique for the treatment of endothelial dysfunction, in which intracameral gas tamponade plays a critical role in graft adherence. We report the case of a 67-year-old pseudophakic woman with advanced Fuchs endothelial corneal [...] Read more.
Descemet stripping automated endothelial keratoplasty (DSAEK) is a well-established surgical technique for the treatment of endothelial dysfunction, in which intracameral gas tamponade plays a critical role in graft adherence. We report the case of a 67-year-old pseudophakic woman with advanced Fuchs endothelial corneal dystrophy and symptomatic pseudophakic bullous keratopathy in the right eye, who presented with progressive visual deterioration and underwent DSAEK using an 8.25 mm donor graft inserted with a Busin glide and tamponaded with a 25% sulfur hexafluoride (SF6) gas–air mixture. On the first postoperative day, slit-lamp examination suggested an appropriate anterior chamber configuration and satisfactory graft attachment. However, detailed multiplanar anterior segment optical coherence tomography (AS-OCT), defined here as assessment using vertical, horizontal, and rotational scan orientations, revealed subtle posterior migration of the gas bubble beneath the iris plane. This clinically occult finding indicated altered anterior segment anatomy associated with a risk of secondary angle-closure mechanisms and raised concern for malignant glaucoma. Prompt surgical re-intervention was undertaken on postoperative day one, involving decompression of the misdirected gas bubble and reinjection of a centrally positioned tamponade. This resulted in restoration of normal anterior chamber configuration and stable graft adherence. Best-corrected visual acuity (BCVA) improved from 0.1 Snellen (1.0 logMAR) preoperatively to 0.7 Snellen (0.15 logMAR) at 2 weeks following surgery. This case highlights the added value of multiplanar AS-OCT in detecting clinically occult posterior gas migration after DSAEK, particularly when the abnormality is scan-orientation-dependent and not apparent on slit-lamp examination, thereby enabling timely intervention in the presence of a potentially sight-threatening postoperative configuration. Full article
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16 pages, 2259 KB  
Article
Corneal Higher-Order Aberrations and Posterior Segment Changes in Keratoconus: A Multimodal OCT and OCTA Study
by Ayşe Tüfekçi Balıkçı, Özlem Candan, Ayşe Burcu and Nurten Ünlü
Diagnostics 2026, 16(8), 1212; https://doi.org/10.3390/diagnostics16081212 - 18 Apr 2026
Viewed by 347
Abstract
Background/Objectives: To evaluate the associations between corneal topographic irregularity, higher-order aberrations (HOAs), and posterior segment structural and microvascular parameters in keratoconus using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: In this cross-sectional study, 81 eyes with keratoconus and 60 healthy [...] Read more.
Background/Objectives: To evaluate the associations between corneal topographic irregularity, higher-order aberrations (HOAs), and posterior segment structural and microvascular parameters in keratoconus using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: In this cross-sectional study, 81 eyes with keratoconus and 60 healthy control eyes underwent corneal topography and wavefront analysis, spectral-domain OCT with enhanced depth imaging, and OCTA. Retinal layer thicknesses, choroidal thickness and area metrics, choroidal vascularity index (CVI), and OCTA-derived vascular parameters were analyzed. Associations were assessed using Spearman correlation analysis with false discovery rate (FDR) correction. Results: Compared with controls, keratoconus eyes showed significantly increased corneal curvature, corneal irregularity indices, and HOAs (all p < 0.001). Structural OCT analysis demonstrated preserved inner retinal layers, whereas outer nuclear layer thickness was reduced (p < 0.001) and overall outer retinal layer thickness was increased (p = 0.005). Choroidal thickness and both total and luminal choroidal areas were significantly greater in keratoconus eyes (all p ≤ 0.011), while CVI did not differ between groups (p > 0.05). OCTA revealed reduced superficial capillary plexus vessel density at the whole image and perifoveal regions (all p < 0.001), whereas deep capillary plexus and foveal avascular zone metrics were largely preserved. Correlation analyses identified only weak and inconsistent associations between corneal parameters, HOAs, and posterior segment measurements, none of which remained statistically significant after FDR correction. Conclusions: Despite pronounced anterior segment deformation and optical degradation, posterior segment structural and microvascular alterations in keratoconus are limited and weakly related to corneal disease severity. These findings support a predominantly anterior segment centered pathophysiology of keratoconus and highlight the importance of stringent multiple-comparison control in multimodal imaging studies. Full article
(This article belongs to the Special Issue Diagnostic Imaging in Ocular Surface)
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5 pages, 6473 KB  
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Multimodal Anterior Segment Imaging of Severe Mixed Exposure-Related Neurotrophic Keratopathy with Marked Corneal Thinning in Lamellar Ichthyosis
by Wojciech Luboń, Małgorzata Luboń and Mariola Dorecka
Diagnostics 2026, 16(8), 1209; https://doi.org/10.3390/diagnostics16081209 - 17 Apr 2026
Viewed by 368
Abstract
Lamellar ichthyosis is a rare congenital disorder of keratinization frequently associated with ocular complications, most commonly cicatricial ectropion and exposure keratopathy. We present a case of severe mixed exposure-related and neurotrophic keratopathy with marked corneal thinning in a 61-year-old man with genetically confirmed [...] Read more.
Lamellar ichthyosis is a rare congenital disorder of keratinization frequently associated with ocular complications, most commonly cicatricial ectropion and exposure keratopathy. We present a case of severe mixed exposure-related and neurotrophic keratopathy with marked corneal thinning in a 61-year-old man with genetically confirmed lamellar ichthyosis. At presentation, the best-corrected visual acuity (BCVA) in the right eye was limited to hand motion (logMAR 2.3). Slit-lamp examination revealed a large central to inferocentral corneal ulcer measuring approximately 3 × 4 mm with severe stromal thinning in the setting of marked lower eyelid ectropion, incomplete eyelid closure, and chronic ocular surface exposure, while anterior segment optical coherence tomography (AS-OCT) demonstrated a minimal corneal thickness of approximately 165 µm. Microbiological swabs obtained from the conjunctival sac were negative, and no purulent discharge, hypopyon, or anterior chamber inflammatory reaction was present, making active infectious keratitis unlikely. Corneal sensitivity measured with Cochet–Bonnet esthesiometry at presentation, centrally and in all four peripheral quadrants of both eyes, was markedly reduced, more severely in the affected right eye, supporting the presence of a severe neurotrophic component contributing to impaired corneal healing. Intensive conservative therapy including preservative-free lubricants, dexpanthenol gel, autologous serum eye drops, topical insulin, prophylactic antibiotics, and systemic doxycycline was initiated. Serial AS-OCT imaging demonstrated progressive structural recovery, with corneal thickness increasing to 438 µm after one month of treatment and complete corneal epithelialization. The BCVA improved to 0.2 Snellen (0.7 logMAR). This case highlights the diagnostic value of multimodal anterior segment imaging in monitoring severe mixed keratopathy with advanced corneal thinning and demonstrates that intensive conservative therapy may stabilize the ocular surface and prevent corneal perforation in patients with lamellar ichthyosis. Full article
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21 pages, 8107 KB  
Article
Lens Alternatives to Microscope Objectives in Optical Coherence Microscopy for Ultra-High-Resolution Imaging
by Xinjie Zhu, Zijian Zhang, Samuel Lawman, Xingyu Yang, Yalin Zheng and Yaochun Shen
Photonics 2026, 13(4), 384; https://doi.org/10.3390/photonics13040384 - 17 Apr 2026
Viewed by 842
Abstract
Ultrahigh lateral resolution (UHLR) optical coherence tomography (OCT) technology, also called optical coherence microscopy (OCM), has gained popularity, especially in the field of biomedical imaging. In these systems, high numerical aperture (NA) Microscope objectives (MO) are employed in OCM systems to offer better [...] Read more.
Ultrahigh lateral resolution (UHLR) optical coherence tomography (OCT) technology, also called optical coherence microscopy (OCM), has gained popularity, especially in the field of biomedical imaging. In these systems, high numerical aperture (NA) Microscope objectives (MO) are employed in OCM systems to offer better than 3 µm lateral resolution. However, in the implemented broadband OCM configuration, the use of complex multi-element microscope objectives can reduce the detected returned signal compared with a simpler imaging lens configuration. This reduction in detected returned signals can become an important practical limitation in many OCM applications, particularly for biomedical imaging when high imaging speed is crucial. This study investigates whether a single off-the-shelf lens can provide a practical alternative to conventional MOs, achieving higher throughput while maintaining reasonable spatial resolution. We systematically evaluated 14 commercial lenses using Zemax OpticStudio simulations, identifying an aspherized achromatic lens (Edmund Optics #85302) that best met these key criteria. To validate its feasibility for OCM, performance was tested in both Full-Field Time-Domain OCM (FF-TD-OCM) and Line-Field Spectral-Domain OCM (LF-SD-OCM) configurations. Using a broadband composite Superluminescent Diode (SLD) source (750–920 nm), we quantified the resolvable features, axial resolution, and overall light transmission. The validated system demonstrated near-diffraction-limited performance. In the LF-SD-OCM setup, it successfully resolved features as fine as Group 8, Element 6, corresponding to a 2.2 µm line pair pitch (~1.1 µm line width) and achieved a 2.86 µm axial resolution in air. A through-focus comparison further showed practically useful contrast retention around focus. Additional imaging of onion epidermal tissue and ex vivo porcine corneal tissue demonstrated that the proposed lens could provide interpretable structural images on representative biological samples. Under the tested LF-SD-OCM detection configuration, the selected lens delivered approximately 2.0 dB higher returned signal than the Mitutoyo MY10X-823 objective according to 1.59× larger received signal. Full article
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11 pages, 819 KB  
Article
Comparison of Corneal Epithelial Thickness Profiles Between Aqueous-Deficient and Evaporative Dry Eye Disease
by Yeonwoo Jin, Sangwon Han and Sun Woong Kim
J. Clin. Med. 2026, 15(8), 3055; https://doi.org/10.3390/jcm15083055 - 16 Apr 2026
Viewed by 422
Abstract
Background/Objectives: Corneal epithelial thickness (CET) alterations reflect distinct mechanisms in aqueous-deficient and evaporative dry eye disease (DED) subtypes. In this study, we compare the CET profiles between patients with Sjögren’s syndrome (SS) and those with meibomian gland dysfunction (MGD) to elucidate the underlying [...] Read more.
Background/Objectives: Corneal epithelial thickness (CET) alterations reflect distinct mechanisms in aqueous-deficient and evaporative dry eye disease (DED) subtypes. In this study, we compare the CET profiles between patients with Sjögren’s syndrome (SS) and those with meibomian gland dysfunction (MGD) to elucidate the underlying mechanisms. Methods: We retrospectively analyzed 30 patients with SS and 30 age- and sex-matched with MGD. Assessments included corneal staining, Ocular Surface Disease Index (OSDI), tear meniscus height (TMH), non-invasive breakup time, lipid layer thickness (LLT), and anterior segment optical coherence tomography (AS-OCT) CET mapping. Regional CET and superior–inferior asymmetry were compared. Results: The SS group exhibited higher corneal staining scores (2.18 ± 1.23 vs. 1.03 ± 1.18, p = 0.001) and lower TMHs (0.14 ± 0.06 vs. 0.18 ± 0.07 mm, p = 0.013), while the MGD group reported greater OSDI scores (40.39 ± 22.49 vs. 31.25 ± 22.81, p = 0.029). A significantly thinner central epithelium (p = 0.043) and localized inferior paracentral thinning (2–5 mm zone, p = 0.008) were noted in SS. Corneal staining was identified as the primary independent predictor of central and inferior CET reduction in both groups. In the MGD group, LLT was associated with the preserved inferior CET (p = 0.045) and superior–inferior thickness difference (p = 0.015). Conclusions: Distinct structural signatures are observed between DED subtypes. SS features central/inferior thinning from aqueous deficiency-mediated friction, whereas MGD shows a relatively preserved epithelial thickness influenced by LLT. Regional CET analysis may provide mechanistic insights into DED subtyping. Full article
(This article belongs to the Special Issue Meibomian Gland Dysfunction and Dry Eye Diseases)
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7 pages, 2549 KB  
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Anterior Segment OCT in Fulminant Pseudomonas aeruginosa Corneal Ulcer with Stromal Melting Requiring Emergency Penetrating Keratoplasty
by Wojciech Luboń, Monika Sarnat-Kucharczyk and Mariola Dorecka
Diagnostics 2026, 16(8), 1189; https://doi.org/10.3390/diagnostics16081189 - 16 Apr 2026
Viewed by 339
Abstract
Rapidly progressive infectious keratitis may involve the anterior uveal tract and lead to anterior segment inflammation, resulting in severe structural damage of the cornea and potentially causing corneal perforation or endophthalmitis if not promptly treated. We report the case of a 63-year-old male [...] Read more.
Rapidly progressive infectious keratitis may involve the anterior uveal tract and lead to anterior segment inflammation, resulting in severe structural damage of the cornea and potentially causing corneal perforation or endophthalmitis if not promptly treated. We report the case of a 63-year-old male admitted to the Emergency Ophthalmology Department of the University Clinical Center in Katowice, Poland, with a rapidly progressive corneal ulcer of the left eye that had not responded to two weeks of outpatient topical antibiotic therapy. The condition developed after ocular trauma sustained while chopping wood. At presentation, visual acuity was limited to light perception with preserved projection. Multimodal imaging, including slit-lamp examination, anterior segment optical coherence tomography (AS-OCT), and in vivo confocal microscopy, revealed extensive corneal ulceration with severe stromal destruction, progressive corneal melting, and marked anterior segment inflammation, with an imminent risk of perforation. Microbiological cultures identified Pseudomonas aeruginosa. Despite intensive empiric topical antimicrobial therapy targeting both bacterial infection and a possible fungal component related to trauma with organic material, rapid clinical deterioration necessitated emergency therapeutic penetrating keratoplasty (PK). The procedure resulted in rapid resolution of inflammation and improvement in visual acuity, with best-corrected visual acuity (BCVA) reaching 0.3 logMAR during follow-up. At the three-month follow-up, the corneal graft remained clear with stable visual acuity and no recurrence of infection. The patient remains under regular long-term follow-up, with ongoing monitoring of graft clarity, intraocular pressure (IOP), and visual function. This case differs from routine presentations of infectious keratitis by demonstrating exceptionally rapid stromal melting despite promptly initiated empiric topical therapy. Multimodal imaging, particularly AS-OCT provided clinically meaningful information by revealing structural instability and an imminent risk of perforation not fully appreciable on slit-lamp examination, thereby supporting timely urgent keratoplasty. These findings highlight the practical diagnostic value of imaging-based assessment in advanced infectious keratitis and underscore its role in guiding surgical decision-making in eyes at high risk of corneal perforation. Full article
(This article belongs to the Special Issue Diagnostic Imaging in Ocular Surface)
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