Anterior Stroma Research Articles

Corneal reshaping: an experiment with a type I collagen-based vitrigel for remodeling porcine corneas.

This study aimed to report an experiment designed to determine anatomical changes in porcine corneas following placement of a novel polymer implant into the cornea. An ex vivo porcine eye model was used. A novel type I collagen-based vitrigel implant (6 mm in diameter) was shaped with an excimer laser on the posterior surface to create three planoconcave shapes. Implants were inserted into a manually dissected stromal pocket at a depth of approximately 200 μm. Three treatment groups were defined: group A (n=3), maximal ablation depth 70 μm; Group B (n=3), maximal ablation depth 64 μm; and group C (n=3), maximal ablation depth 104 μm, with a central hole. A control group (D, n=3) was included, in which a stromal pocket was created but biomaterial was not inserted. Eyes were evaluated by optical coherence tomography (OCT) and corneal tomography. Corneal tomography showed a trend for a decreased mean keratometry in all four groups. Optical coherence tomography showed corneas with implants placed within the anterior stroma and visible flattening, whereas the corneas in the control group did not qualitatively change shape. The novel planoconcave biomaterial implant described herein could reshape the cornea in an ex vivo model, resulting in the flattening of the cornea. Further studies are needed using in vivo animal models to confirm such findings.

Prostate Imaging Reporting and Data System (PI-RADS) v 2.1: Overview and Critical Points

The technical parameters and imaging interpretation criteria of the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) using multiparametric MRI (mpMRI) are updated in PI-RADS v2.1. These changes have been an expected improvement for prostate cancer evaluation, although some issues remain unsolved, and new issues have been raised. In this review, a brief overview of PI-RADS v2.1 is and several critical points are discussed as follows: the need for more detailed protocols of mpMRI, lack of validation of the revised transition zone interpretation criteria, the need for clarification for the revised diffusion-weighted imaging and dynamic contrast-enhanced imaging criteria, anterior fibromuscular stroma and central zone assessment, assessment of background signal and tumor aggressiveness, changes in the structured report, the need for the parameters for imaging quality and performance control, and indications for expansion of the system to include other indications.

Anterior fibromuscular stroma-preserved endoscopic enucleation of the prostate: a precision anatomical approach.

Benign prostate obstruction (BOO) is becoming increasingly important in this aging society. Some urge/stress urinary incontinence (UUI/SUI) still occurs after endoscopic enucleation of the prostate (EEP). It remains unclear how post-EEP incontinence can be avoided. Currently, early apical release to ameliorate the traction of the external sphincter is the best technique for incontinence prevention. To describe our surgical technique of anterior fibromuscular stroma (AFS)-preserved EEP for BOO. The medical records of 60 consecutive patients who underwent AFS-preserved EEP for BOO in our center from September 2019 to December 2019 were retrospectively reviewed. AFS-preserved EEP starts at the 12 o'clock position of the urethra, and the junction between the AFS and transitional zone (T-zone) was identified. The AFS and T-zone were separated first to protect the AFS in the initial operative procedure. Then, following the usual enucleation procedure, AFS-preserved EEP could be achieved. Postoperative prostate-specific antigen (PSA), testosterone, urethral stricture, and voiding status, such as incontinence, uroflow, and postvoiding residual urine were assessed. The data show that AFS-preserved EEP could achieve similar surgical outcomes as other early apical release approaches. The preserved AFS provides a nice landmark at the 12 o'clock position during EEP.

Quantitative Evaluation of In Vivo Corneal Biomechanical Properties after SMILE and FLEx Surgery by Acoustic Radiation Force Optical Coherence Elastography.

The purpose of this study is to quantitatively evaluate the differences in corneal biomechanics after SMILE and FLEx surgery using an acoustic radiation force optical coherence elastography system (ARF-OCE) and to analyze the effect of the corneal cap on the integrity of corneal biomechanical properties. A custom ring array ultrasound transducer is used to excite corneal tissue to produce Lamb waves. Depth-resolved elastic modulus images of the in vivo cornea after refractive surgery were obtained based on the phase velocity of the Lamb wave. After refractive surgery, the average elastic modulus of the corneal flap decreased (71.7 ± 24.6 kPa), while the elastic modulus of the corneal cap increased (219.5 ± 54.9 kPa). The average elastic modulus of residual stromal bed (RSB) was increased after surgery, and the value after FLEx (305.8 ± 48.5 kPa) was significantly higher than that of SMILE (221.3 ± 43.2 kPa). Compared with FLEx, SMILE preserved most of the anterior stroma with less change in corneal biomechanics, which indicated that SMILE has an advantage in preserving the integrity of the corneal biomechanical properties. Therefore, the biomechanical properties of the cornea obtained by the ARF-OCE system may be one of the essential indicators for evaluating the safety of refractive surgery.

Susceptibility of the Intact and Traumatized Feline Cornea to In Vitro Binding and Invasion by Acanthamoeba castellanii.

Acanthamoeba castellanii ( A. castellanii ) displays host specificity at the level of the ocular surface. This study determined the susceptibility of the intact and traumatized feline cornea to A. castellanii binding and invasion relative to other host species with established susceptibility and resistance to Acanthamoeba binding. Full-thickness buttons of fresh feline, porcine, and canine corneas were prepared. The corneal epithelium was confirmed intact by fluorescein staining or lightly scarified with a 25-G needle to simulate corneal trauma. Acanthamoeba castellanii was axenically cultivated. Corneal buttons were incubated with the parasite suspension or parasite-free medium for 18 hours at 35°C. Corneal buttons were rinsed, fixed, and processed for histopathology and immunohistochemistry using immunoperoxidase and immunofluorescence methods of amoeba detection. Numerous amoebae were bound to feline and porcine corneas incubated with parasites. In both intact and traumatized corneas, amoebae were detected at all levels in the corneal epithelium and within the anterior stroma. In traumatized corneal sections, amoebae were frequently present in regions of epithelial damage. Corneal architecture was well-preserved in sections incubated with parasite-free medium; however, epithelial cell sloughing, separation of epithelial layers, and epithelial detachment from the stroma were observed in corneas incubated with amoebae. Intact and traumatized canine corneas were relatively free of adherent amoebae, and corneal architecture was indistinguishable between sections incubated with the parasite suspension and parasite-free medium. The feline cornea is highly susceptible to in vitro binding and invasion by A. castellanii . Acanthamoeba binding to the feline cornea does not require a previous epithelial defect.

Interaction of immune cells and lymphatic vessels in corneal transplantation

AbstractImmune‐mediated graft rejections remain the most common cause for graft failure after organ and tissue transplantation. There is a great unmet medical need for pharmacologic strategies to promote graft survival without unduly compromising the health of the recipient.Corneal allograft rejection is histologically characterized by massive infiltration of CD4+ T‐cells, macrophages and the invasion of blood and lymphatic vessels.We could show that lymphatic vessels determine the high‐risk status of a corneal graft recipient. The healthy cornea is devoid of blood and lymphatic vessels. In contrast, in the high risk situation graft rejection is highly correlated with the degree of corneal vascularisation and presence of numerous pro‐inflammatory immune cells.CD11c+ CD11b+ myeloid dendritic cells (DCs) are present throughout the anterior stroma – even in the healthy cornea. Inflammatory stimuli determine the maturation stage of DCs and their immunogenic properties. It is known that an increasing number of MHC class II‐bearing, antigen specific DCs in cervical draining lymph nodes arise only a few hours after transplantation. This implies that DCs at different maturation stages might be the main initiators of this devastating tissue destruction.The origin of donor antigen presenting cells can be either from the donor tissue or the host. Thereby allo‐antigens from the grafted tissues travel via lymphatic vessels towards the draining lymph nodes of the recipient. Here they are recognized by host T cells either by the direct pathway, which involves the recognition of intact donor MHC molecules on donor‐derived APCs, or by the indirect pathway, which involves the recognition of donor major or minor MHC‐derived peptides, processed and presented by recipient APCs to host T cells. Nowadays it is widely accepted that resident MHC class II APC populations are present in the cornea. These cells are capable of expressing MHC class II antigen and accessory molecules (CD40, CD80) after transplantation. We and others could demonstrate that the immune reaction is triggered by the above described “direct allo‐sensitisation” where APCs travel from the donor tissue via corneal pathological lymphatic vessels into the local draining lymph nodes of the recipient and present the foreign antigen.Recent studies could show that lymphatic vessels not just display an exit route for leukocytes but are in close interaction with these cells and regulate the entry and trafficking of antigen presenting cells into and via lymphatic vessels.This presentation will summarize the current knowledge about the interaction of immune cells and lymphatic vessels in corneal transplantation.

Infectious Crystalline Keratopathy after Penetrating Keratoplasty with Light and Electron Microscopic Examination.

To highlight the typical histological and ultrastructural features of severe infectious crystalline keratopathy (ICK) in a corneal graft, which required excimer laser-assisted repeat penetrating keratoplasty (PKP) and to present the challenging treatment conditions associated with ICK. An 85-year-old female patient underwent PKP for secondary graft failure after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs' endothelial corneal dystrophy in the left eye. One year later, white branched opacities were observed in the superficial corneal stroma of the graft without surrounding inflammation in the left eye. The patient underwent excimer laser-assisted repeat PKP (8.0/8.1 mm) in the left eye after prolonged refractory topical anti-infectious treatment for 1 month. The corneal explant was further examined by light and transmission electron microscopy (TEM). The light microscopic examination of the corneal explant demonstrated aggregates of coccoid bacteria in the superficial and mid-stromal region that were positive for periodic acid-Schiff (PAS) and Gram stain. The bacterial aggregates extended into the interlamellar spaces, showed a spindle-shaped appearance, and were not surrounded by an inflammatory cellular reaction. TEM demonstrated lamellae separation within the anterior corneal stroma with spindle-shaped aggregates of bacteria, which were embedded in an extracellular amorphous matrix with incipient calcification, being consistent with a biofilm. No inflammatory cellular reaction was evident by TEM. At discharge from hospital, the corrected visual acuity was 20/80 in the left eye. ICK is often challenging due to the difficult diagnosis and treatment conditions. The refractory courses are mainly attributed to a biofilm formation, which inhibits effective topical anti-infectious treatment. In such cases, (repeat) PKP may be necessary to completely remove the pathology, prevent recurrences, and improve vision.

Biomechanical profile of refractive procedures; is there a biomechanical privilege?

AbstractThe cornea shows regional in‐plane variation in strain and deformation. Paracentral and peripheral cornea is stiffer than the central cornea due to differing orientation and number of collagen fibrils. Corneal elastic strength is a function of depth, with decreasing strength from the anterior to the posterior stroma.During central myopic ablation, an immediate circumferential severing of corneal lamellae is produced. resulting in a forward herniation. Additionally central ablation also relaxes lamellar tension in residual peripheral lamellar segments, which decreases local resistance to swelling leading to peripheral stromal thickening. Expansion of the peripheral stroma may generate centripetal stress in underlying lamellae through dense interlamellar connections at the margin of the ablation zone, resulting central flattening.Empirically, the hyperopic response is dominant when ablation is limited to the anterior stroma, and progressively deeper circumferential insults result in a shift towards corneal steepening. Central flattening response augments the effects of a myopic procedure but impedes efforts to correct hyperopia.

Rediscovering a valuable manual Deep Anterior Lamellar Keratoplasty (DALK) technique: Outcomes of 42 "Peeling-off" DALK.

Residual bed thickness in DALK should be less than 80μm to provide optimal visual outcomes. "Peeling-off" is a manual DALK technique, which separates the anterior stroma by pulling the deep stromal lamellae following the plane of their lowest adhesion, which is usually very deep. The purpose of this study is to measure the residual bed thickness achievable with this technique. Retrospective case series of "Peeling-off" DALK cases performed between January 2014 and January 2021 with at least 1 year of follow-up. Indications for DALK, intraoperative and postoperative complications, residual recipient bed thickness at 1 day and at 1 month after surgery, and postoperative best corrected visual acuity (BCVA) at 1 year of follow up were evaluated. 42 eyes (42 patients) underwent DALK performed with "Peeling-off" technique. Indications for surgery were keratoconus in 33 eyes and stromal scar in 9 eyes. "Peeling-off" technique was used as a rescue approach to perform a DALK after a failed Big-Bubble in all cases, and also failed Air-Visco-Bubble in some cases. No intraoperative and postoperative complications were recorded. Residual recipient bed thickness was deep and regular, measuring 42 microns at 1 day postoperative (range 21-65 microns) and 23 microns (range 17-26 microns) at 1 month postoperative. Mean postoperative BCVA at 1 year of follow up was 0.18 logMAR ± 0.09. "Peeling-off" DALK is a valuable manual technique that achieves a deep stromal plane with optimal visual outcomes.

Expression Pattern of Tenascin-C, Matrilin-2, and Aggrecan in Diseases Affecting the Corneal Endothelium.

Purpose: The aim of this study was to examine the expression pattern of tenascin-C, matrilin-2, and aggrecan in irreversible corneal endothelial pathology such as pseudophakic bullous keratopathy (PBK) and Fuchs’ endothelial corneal dystrophy (FECD), which most frequently require corneal transplantation. Materials and methods: Histological specimens of corneal buttons removed during keratoplasty were investigated in PBK (n = 20) and FECD (n = 9) and compared to healthy control corneas (n = 10). The sections were studied by chromogenic immunohistochemistry (CHR-IHC) and submitted for evaluation by two investigators. Semiquantitative scoring (0 to 3+) was applied according to standardized methods at high magnification (400x). Each layer of the cornea was investigated; in addition, the stroma was subdivided into anterior, middle, and posterior parts for more precise analysis. In case of non-parametric distribution Mann–Whitney test was applied to compare two groups. Kruskal–Wallis and Dunn’s multiple comparisons tests have been applied for comparison of the chromogenic IHC signal intensity among corneal layers within the control and patient groups. Differences of p < 0.05 were considered as significant. Results: Significantly elevated tenascin-C immunopositivity was present in the epithelium and every layer of the stroma in both pathologic conditions as compared to normal controls. In addition, also significantly stronger matrilin-2 positivity was detected in the epithelium; however, weaker reaction was present in the endothelium in PBK cases. Minimal, but significantly elevated immunopositivity could be observed in the anterior and posterior stroma in the FECD group. Additionally, minimally, but significantly higher aggrecan immunoreaction was present in the anterior stroma in PBK and in the posterior stroma in both endothelial disorders. All three antibodies disclosed the strongest reaction in the posterior stroma either in PBK or in FECD cases. Conclusions: These extracellular matrix molecules disclosed up to moderate immunopositivity in the corneal layers in varying extents. Through their networking, bridging, and adhesive abilities these proteins are involved in corneal regeneration and tissue reorganization in endothelial dysfunction.

Salzmann’s Nodular Degeneration

Saltzman’s nodular degeneration is a rare, non-inflammatory, slowly progressive degenerative disease of the cornea characterized by bluish-white nodules elevated above the surface of the cornea. More often nodules are located in the mid periphery of the cornea, they can spread into the optical zone. Sometimes localize along the limbus. They consist of dense heterogeneous collagen tissue with hyalinization, localized between the epithelium and Bowman’s layer. Can penetrate deeper into the stroma. The exact pathophysiological mechanism of the lesion is unclear. It is considered that this condition is associated with a violation of the structural relationship of epithelial cells against the background of chronic inflammation of the ocular surface, which leads to the destruction of the Bowman’s layer, the activation and migration of fibroblasts anteriorly, and the deposition of a disorganized extracellular matrix in subepithelial nodules. Clinically, the disease can be manifested by irritation and inflammation of the ocular surface, dryness or decreased vision, more often due to flattening of the cornea and astigmatism. In some cases, the formed tissue can be easily separated from the corneal surface, leaving Bowman’s layer almost intact. In this case, a subsequent phototherapeutic keratectomy may be required to “smooth” the surface. Relapses in these eyes are rare. In other situations (often with extensive peripheral vascularization), the lesions involve the anterior stroma, making it more difficult to remove them while maintaining the smoothness of the cornea. Several laser ablation procedures may be required, but there is a high risk of recurrence with this approach. It may be necessary to treat the meibomian gland’ dysfunction and dry eye syndrome that often accompanies Saltzman’s degeneration to reduce the risk of disease progression.

Segmentation of the prostate, its zones, anterior fibromuscular stroma, and urethra on the MRIs and multimodality image fusion using U-Net model.

BackgroundDue to the large variability in the prostate gland of different patient groups, manual segmentation is time-consuming and subject to inter-and intra-reader variations. Hence, we propose a U-Net model to automatically segment the prostate and its zones, including the peripheral zone (PZ), transitional zone (TZ), anterior fibromuscular stroma (AFMS), and urethra on the MRI [T2-weighted (T2W), diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC)], and multimodality image fusion.MethodsA total of 91 eligible patients were retrospectively identified; 50 patients were considered for training process in a 10-fold cross-validation fashion and 41 ones for external test. Firstly, images were registered, and cropping was performed through a bounding box. In addition to T2W, DWI, and ADC separately, fused images were used. We considered three combinations, including T2W + DWI, T2W + ADC, and DWI + ADC, using wavelet transform. U-Net was applied to segment the prostate and its zones, AFMS, and urethra in a 10-fold cross-validation fashion. Eventually, dice score (DSC), intersection over union (IoU), precision, recall, and Hausdorff distance (HD) were used to evaluate the proposed model.ResultsUsing T2W images alone on the external test images, higher DSC, IoU, precision, and recall was achieved than the individual DWI and ADC images. DSC of 95%, 94%,98%, 94%, and 88%, IoU of 88%, 88.5%, 96%, 90%, and 79%, precision of 95.9%, 93.9%, 97.6%, 93.83%, and 87.82%, and recall of 94.2%, 94.2%, 98.3%, 94%, 87.93% was achieved for the whole prostate, PZ, TZ, urethra, and AFMS, respectively. The results clearly show that the best segmentation was obtained when the model is trained using T2W + DWI images. DSC of 99.06%, 99,05%, 99.04%, 99.09%, and 98.08%, IoU of 97.09%, 97.02%, 98.12%, 98.13%, and 96%, precision of 99.24%, 98.22%, 98.91%, 99.23%, and 98.9%, and recall of 98.3%, 99.8%, 99.02%, 98.93%, and 97.51% was achieved for the whole prostate, PZ, TZ, urethra, and AFMS, respectively. The min of the HD in the testing set for three combinations was 0.29 for the T2W + ADC procedure in the whole prostate class.ConclusionsBetter performance was achieved using T2W + DWI images than T2W, DWI, and ADC separately or T2W + ADC and DWI + ADC in combination.

Complications in deep anterior lamellar keratoplasty - A retrospective interventional analysis in a large series.

To analyze the complications in patients managed with deep anterior lamellar keratoplasty (DALK) for diseases of the anterior corneal stroma. This is a retrospective analysis of all the patients who underwent DALK in a tertiary care center in South India from 2010 to 2020. A total of 474 eyes in 373 patients were included in the study. Patients who underwent DALK for advanced keratoconus, keratoconus with Bowman's membrane scar, healed hydrops, macular corneal opacity, macular corneal dystrophy, granular corneal dystrophy, spheroidal degeneration, pellucid marginal degeneration, post-laser-assisted in situ keratomileusis ectasia, descematocele, post-collagen cross-linking aborted melt and dense scar, and post-radial keratotomy were included in the study. The patients were followed up for 17.2 +/- 9.2 months (1-9 years). Complications noted in the surgery were intra-operatively Descemet's membrane perforation in 31 eyes (6.54%), post-operatively secondary glaucoma in 16 eyes (3.37%), cataract in seven eyes (1.47%), suture-related complications in five eyes (1.05%), graft rejection in three eyes (0.63%), traumatic dehiscence in two eyes (0.42%), filamentary keratitis in two eyes (0.42%), interface infiltrate in one eye (0.21%), and recurrence of disease in four eyes (7.14%) out of 57 eyes with corneal dystrophy. DALK as an alternative to penetrating keratoplasty for anterior corneal stromal diseases. It has become an automatic choice for diseases of the anterior cornea requiring keratoplasty. Complications can occur at any stage of surgery; however, if identified and managed early, they can result in optimal outcome.

Corneal histomorphology and electron microscopic observation of R124L mutated corneal dystrophy in a relapsed pedigree.

To investigate the histological characteristics and ultrastructure of recurrent Chinese R124L mutated corneal dystrophy after keratoplasty. The subjects were enrolled from a Chinese family of corneal dystrophy with R124L heterozygous gene mutation and with a history of consanguineous marriage. Normal corneal samples were used as controls. In this family, 2 patients (3 eyes) underwent penetrating keratoplasty (PKP) and 2 patients (4 eyes) underwent lamellar keratoplasty (LKP). They had recurrence at 33.5±3.0 (range 30-36)mo after keratoplasty. Among them, 1 patient (1 eye) underwent PKP again and 1 patient (2 eyes) underwent LKP again. In the R124L mutated recurrent corneal dystrophy, the corneal turbidity was mainly distributed from the upper corneal cortex to the anterior stroma; the corneal epithelium surface was rougher and more uneven; and, the corneal erosions were larger. Hematoxylin-eosin staining showed that the thickness of the corneal epithelium was uneven; the arrangement of the epithelial cells was disordered; and, some corneal epithelial cells were swollen. The results of Congo red staining, Masson's trichrome staining and Periodic acid-Schiff staining were positive, while that of Alcian blue staining was negative. Under a transmission electron microscope, deposition of high electron density substances between epithelial and basal cells, and, apoptosis of basal cells were observed. Many high electron density depositions were observed in the sub-epithelial and anterior corneal matrix. In the Chinese family of recurrent corneal dystrophy with R124L gene mutation, the corneal epithelia of the recurrent cases are rougher, and the corneal depositions are extracellular amyloid fibrin.

Aberrant Corneal Homeostasis in Neurosurgery-Induced Neurotrophic Keratopathy.

The characteristic features of neurotrophic keratopathy have been well documented by in vivo and in vitro studies using animal models. However, case reports of neurotrophic keratopathy induced by neurosurgery are limited. We describe the clinical characteristics, anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) findings of neurotrophic keratopathy induced by surgery for intracranial lesions. This is a case series including 6 eyes of 3 patients (mean age, 69.67 ± 12.50 years) with unilateral neurotrophic keratopathy. The clinical findings of three patients were described and IVCM findings of three patients were analyzed. The duration of neuropathy ranged from 2 to 30 years (median, 22 years). Thickening of the epithelial layer and higher reflection density of the anterior stroma were observed during the healing process using AS-OCT. The mean nerve fiber density of the subepithelial plexus, as determined by IVCM, was 1943 ± 1000 μm/mm2 for neurotrophic eyes and 2242 ± 600.3 μm/mm2 for contralateral eyes (p = 0.0347). The mean respective dendritic cell densities were 30.8 ± 21.8 and 6.25 ± 5.59 cells/mm2 (p < 0.0001), while the mean basal cell sizes were 259 ± 86.5 and 185 ± 45.9 μm2 (p < 0.0001), respectively. These findings suggest that neurosurgery-induced neurotrophic keratopathy may be associated with alterations in the healing process and immune cell distribution in the cornea.

Corneal stromal depth of the demarcation line after accelerated versus conventional cross-linking

Background: Keratoconus is one of ectatic corneal disease which is characterized by corneal steepening, visual distortion, apical corneal thinning, and central corneal scarring. Its exact etiology is unknown. Aim and objectives: to assess the depth of the corneal stromal demarcation line (a transition zone between the cross-linked anterior corneal stroma and the untreated posterior corneal stroma,which is considered a measurement of the depth of cross-linking treatment into the stroma). 6 After conventional crosslinking versus accelerated crosslinking after one and three months postoperative. Subjects and methods: This Prospective, randomized, comparative, cross-sectional study was conducted in Kobri El Qobba Military specialized eye hospital, Cairo, Egypt. This study was conducted on 40 eyes with progressive keratoconus divided into two groups, each of them included 20 eyes: group 1: 20 eyes underwent accelerated cross-linking, and group 2: 20 eyes underwent conventional (standard) cross-linking. Results: The demarcation line and Kmax at 1-month and 3-months postoperative showed no statistically difference between the two studied groups. Conclusion: cross-linking is a safe and efficient treatment in progressive keratoconus. Accelerated CXL was comparable with conventional CXL at all-time points and both conventional and accelerated CXL significantly improve CCT and Demarcation line depth.

Delayed Laser In Situ Keratomileusis Interface Haze 6 Months After Corneal Cross-linking for Ectasia

PURPOSE: To report a case of delayed subepithelial haze at the laser in situ keratomileusis (LASIK) flap interface after corneal cross-linking (CXL) for LASIK-induced ectasia. METHODS: A 39-year-old woman with ectasia after LASIK underwent accelerated CXL with riboflavin and hydroxypropyl methylcellulose every 2 minutes for 20 minutes, then ultraviolet light at a fluence of 10 mW/cm 2 for 9 minutes. Outcomes measured included stromal haze assessment and visual refractive parameters. Follow-up was conducted using slit-lamp imaging, optical coherence tomography (OCT), corneal topography, and a dedicated OCT image analysis software. RESULTS: Six months after CXL, OCT of the right eye showed a sharply demarcated hyperreflective linear lesion inferotemporal to the corneal center, at the LASIK flap interface. The haze was 1.5-mm wide with 12.49 grayscale units (GSU) intensity and involved the anterior stroma at 0.9 mm away from the center extending from 225° to 255°. This haze peaked at 9 months after CXL, reaching 3 mm in size and 29.01 GSU in intensity. Corneal topography showed steepening on the haze area and flattening on the diametrically opposite side. Topical steroid therapy was initiated. At final evaluation (19 months), there was a significant decrease in haze reflectivity and size, accompanied by marked improvement of the topography. CONCLUSIONS: Delayed corneal haze after CXL with a history of LASIK can develop at the level of the LASIK interface right under the cone area. Although it was responsive to topical steroid therapy, the reasons for this clinical presentation are still unknown. [ Journal of Refractive Surgery Case Reports. 2022;2(2):e46–e50.]

Molecular characterization of CTNSmutations in Tunisian patients with ocular cystinosis.

BackgroundOcular cystinosis is a rare autosomal recessive disorder characterized by intralysosomal cystine accumulation in renal, ophthalmic (cornea, conjunctiva), and other organ abnormalities. Patients with ocular cystinosis are mostly asymptomatic and typically experience mild photophobia due to cystine crystals in the cornea observed accidently during a routine ocular examination. The ocular cystinosis is associated with different mutations in CTNS gene. Cysteamine therapy mostly corrects the organ abnormalities.MethodsThis study was performed in collaboration with the department of ophthalmology of Farhat Hached Hospital. The Optical Coherence Tomography (OCT) of the cornea and retinal photography were used to search cystine crystals within the corneas and conjunctiva in eight Tunisian patients. Screening for the common 57-kb deletion was performed by standard multiplex PCR, followed by direct sequencing of the entire CTNS gene.ResultsThe studied patients were found to have cystine crystal limited anterior corneal stroma and the conjunctiva associated with retinal crystals accumulation. CTNS gene sequencing disclosed 7 mutations: three missense mutations (G308R, p.Q88K, and p.S139Y); one duplication (C.829dup), one framshift mutation (p.G258f), one splice site mutation (c.681 + 7delC) and a large deletion (20,327-bp deletion). Crystallographic structure analysis suggests that the novel mutation p.S139Y is buried in a first transmembrane helix closed to the lipid bilayer polar region, introducing a difference in hydrophobicity which could affect the hydrophobic interactions with the membrane lipids. The second novel mutation p.Q88K which is located in the lysosomal lumen close to the lipid membrane polar head region, introduced a basic amino acid in a region which tolerate only uncharged residue. The third missense mutation introduces a positive change in nonpolar tail region of the phospholipid bilayer membrane affecting the folding and stability of the protein in the lipid bilayer.ConclusionsOur data demonstrate that impaired transport of cystine out of lysosomes is the most common, which is obviously associated with the mutations of transmembrane domains of cystinosine resulting from a total loss of its activity.

Investigating Scarless Tissue Regeneration in Embryonic Wounded Chick Corneas.

Chick embryonic corneal wounds display a remarkable capacity to fully and rapidly regenerate, whereas adult wounded corneas experience a loss of transparency due to fibrotic scarring. The tissue integrity of injured embryonic corneas is intrinsically restored with no detectable scar formation. Given its accessibility and ease of manipulation, the chick embryo is an ideal model for studying scarless corneal wound repair. This protocol demonstrates the different steps involved in wounding the cornea of an embryonic chick in ovo. First, eggs are windowed at early embryonic ages to access the eye. Second, a series of in ovo physical manipulations to the extraembryonic membranes are conducted to ensure access to the eye is maintained through later stages of development, corresponding to when the three cellular layers of the cornea are formed. Third, linear cornea wounds that penetrate the outer epithelial layer and the anterior stroma are made using a microsurgical knife. The regeneration process or fully restored corneas can be analyzed for regenerative potential using various cellular and molecular techniques following the wounding procedure. Studies to date using this model have revealed that wounded embryonic corneas display activation of keratocyte differentiation, undergo coordinated remodeling of ECM proteins to their native three-dimensional macrostructure, and become adequately re-innervated by corneal sensory nerves. In the future, the potential impact of endogenous or exogenous factors on the regenerative process could be analyzed in healing corneas by using developmental biology techniques, such as tissue grafting, electroporation, retroviral infection, or bead implantation. The current strategy identifies the embryonic chick as a crucial experimental paradigm for elucidating the molecular and cellular factors coordinating scarless corneal wound healing.

PD57-09 THE IMPORTANCE OF MRI-TARGETED BIOPSY FOR TUMORS IN ANTERIOR FIBROMUSCULAR STROMA

You have accessJournal of UrologyCME1 May 2022PD57-09 THE IMPORTANCE OF MRI-TARGETED BIOPSY FOR TUMORS IN ANTERIOR FIBROMUSCULAR STROMA Hayato Yamamoto, Teppei Okamoto, Toru Yoneyama, and Chikara Ohyama Hayato YamamotoHayato Yamamoto More articles by this author , Teppei OkamotoTeppei Okamoto More articles by this author , Toru YoneyamaToru Yoneyama More articles by this author , and Chikara OhyamaChikara Ohyama More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002637.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Anterior prostate cancers are frequently missed since they can be neither palpable nor tangible on physical examination. The objective of this study was to analyze the MRI/transrectal ultrasound-fusion biopsies to detect and to characterize significant prostate cancer in the anterior fibromuscular stroma (AFS) and in the transition zone of the prostate. METHODS: One hundred and fourteen patients underwent prebiopsy 3 T multi parametric (mp) MRI and transperineal biopsy between February 2019 and May 2021. MRI images were analyzed using PIRADS (Prostate Imaging-Reporting and Data System) ver 2. All patients had systematic biopsies and targeted biopsies with rigid software registration in case of MRI-suspicious lesions. RESULTS: The positive rates of systematic and targeted biopsies were 10% and 29%, respectively with a significant difference. The cancer occupancy rate of the biopsy specimens was higher in the targeted biopsy, 22.2% and 36.3%, respectively. There were AFS tumors in 23 of 114 patients, and they harbored 23 lesions (10%) in AFS on mpMRI. The positive rate of targeted biopsy by PI-RADs category was 77% for PI-RADs 5, 42% for PI-RADs 4, and 16% for PI-RADs 3. The positive rate by target region were 24%, 31%, and 83% for peripheral zone (PZ), transition zone (TZ), and AFS, respectively. Especially, in PIRADs category 3 region, the positive rate in AFS region was a high positivity rate of 100%. CONCLUSIONS: Targeted biopsy has improved cancer detection rates. However, we should also pay attention to lesions of low PIRADs category in the AFS region. Source of Funding: none © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e964 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hayato Yamamoto More articles by this author Teppei Okamoto More articles by this author Toru Yoneyama More articles by this author Chikara Ohyama More articles by this author Expand All Advertisement PDF DownloadLoading ...