Dystrophy Of Cornea Research Articles

Corneal Backscatter, Pachymetric Indices, and Ectasia Indices for the Assessment of Fuchs Endothelial Corneal Dystrophy.

To determine whether corneal backscatter, pachymetric indices, and ectasia indices derived from Scheimpflug tomography can identify Fuchs endothelial corneal dystrophy (FECD) corneas with abnormal tomography, the relationships between these parameters and tomographic edema in FECD, and if these parameters help predict improvement in central corneal thickness (CCT) after Descemet membrane endothelial keratoplasty (DMEK). Tomography maps of 132 eyes of 80 subjects with FECD were analyzed to determine how backscatter, pachymetric, and ectasia parameters compared with the instrument's normative database and if any predicted tomographic edema. Tomography maps from a separate group undergoing DMEK were split into derivation (48 eyes of 39 subjects) and validation (45 eyes of 41 subjects) subgroups to derive a predictive model of improvement in CCT after DMEK. Backscatter, pachymetric, and ectasia parameters were incorporated to determine if the model could be enhanced. Among all ectasia, pachymetric, and backscatter parameters, at best only 65% of FECD corneas with definite tomographic edema could be identified based on the instrument's normative database. Among all parameters individually, the highest sensitivity for detecting tomographic edema was 77%. Anterior and mid-corneal backscatter featured in a model predicting improvement in CCT after DMEK with high performance in derivation (R2 = 0.79; 95% confidence interval, 0.65-0.87) and validation (R2 = 0.72; 95% confidence interval, 0.52-0.83) subgroups. The Scheimpflug camera software program could not reliably detect abnormal tomography in FECD from corneal backscatter, pachymetric indices, or ectasia indices. Corneal backscatter contributes to, but does not enhance, a predictive model of improvement in CCT after DMEK.

Segmentation of the fibrillar layer in advanced fuchs endothelial corneal dystrophy: Inter‐oberserver‐reliability and intra‐observer‐repeatability analysis of corneal densitometry images

Aims: Our previous studies state that a central subendothelial collagen‐rich fibrillar layer (FL) is present in about 80% of advanced Fuchs endothelial corneal dystrophy (FECD) corneas which correlates with decreased corneal endothelial cell density and focal oedema formation. In this study, we investigated the previously unknown inter‐observer reliability and intra‐observer reproducibility of FL segmentation on Scheimpflug corneal densitometry images in patients with advanced FECD.Methods: Preoperative Scheimpflug images of patients receiving DMEK or triple DMEK for advanced FECD were retrospectively analysed. FL‐negative cases were excluded. Images were manually segmented with the open‐source software MITK by two experienced graders. A MATLAB‐based code calculated the region of interest (ROI) area, maximum calliper length, maximum horizontal and vertical dimension, and Dice similarity coefficient for FL‐areas. The intraclass correlation coefficient (ICC) was calculated by IBM SPSS (two‐way mixed, average measures). The FL localization on corneal densitometry were visualized by spatial heatmaps by MATLAB.Results: Among 308 eyes, 248 were FL‐positive (80.5%) and 60 FL‐negative (19.5%). The average Dice similarity coefficient of FL areas segmented by two graders was calculated at 0.85. Calculations on the segmentations of Grader 1 vs. Grader 2 include: ROI 7.91mm2 ± 4.8 vs. 9.29 mm2 ± 5.0, Calliper length 4.07 mm ± 1.1 vs. 4.21 mm ± 1.0, maximum horizontal dimension 3.85 mm ± 1.1 vs. 3.95 mm ± 1.0, maximum vertical dimension 3.17 mm ± 1.0 vs. 3.3 mm ± 1.0. The ICC was calculated at 0.938 vs. 0.957 vs. 0.930 for ROI (0.955 vs. 0.960 vs. 0.944 calliper length, 0.958 vs. 0.959 vs. 0.946 maximum horizontal dimension, 0.952 vs. 0.941 vs. 0.945 maximum vertical dimension) and 0.85 vs. 0.86 vs. 0.89 for the Dice similarity coefficient (inter‐observer vs. intra‐observer Grader 1 vs. intra‐observer Grader 2). Spatial heatmap analysis demonstrated primarily inferotemporal localization of increased densitometry areas in FL‐positive eyes.Conclusions: FL segmentation on corneal densitometry images exhibit high inter‐observer reliability and intra‐observer reproducibility scores. We provide evidence for corneal densitometry images as a valid tool to detect FL in advanced FECD and confirm the inferotemporal corneal projection of FL.

The versatile roles of lumican in eye diseases: A review

Lumican is a keratan sulfate proteoglycan that belongs to the small leucine-rich proteoglycan family. Research has lifted the veil on the versatile roles of lumican in the pathogenesis of eye diseases. Lumican has pivotal roles in the maintenance of physiological tissue homogenesis and is often upregulated in pathological conditions, e.g., fibrosis, scar tissue formation in injured tissues, persistent inflammatory responses and immune anomaly, etc.Herein, we will review literature regarding the role of lumican in pathogenesis of inherited congenital and acquired eye diseases, e.g., cornea dystrophy, cataract, glaucoma and chorioretinal diseases, etc.

Lumican expression in chronic degenerative cornea diseases

The pattern of lumican expression in corneal explants of patients with chronic dystrophic cornea diseases and the changes in its expression after 1 % sodium hyaluronate expression are established. The prospective study included 37 patients with chronic dystrophic diseases of the cornea: keratopathies in the outcome of keratitis (20 cases) and endothelial-epithelial dystrophy (17 cases). The patients were divided into 2 groups. The first group in the preoperative period received the injections of 1 % low molecular weight sodium hyaluronate, the second group did not receive additional treatment. All patients included in the study underwent penetrating keratoplasty. The immunohistochemical study of corneal explants was performed using primary monoclonal antibodies to lumican with subsequent morphometric evaluation of the preparations. The proportion of pixels with high and moderate intensity and the index of expression intensity in immunopositive regions were calculated. In the group of patients with aggressive keratitis, the intensity of lumican expression both in the epithelium and in the corneal stroma was statistically significantly higher than in the control group and decreased with the use of 1 % low molecular weight sodium hyaluronate. After the leukoma formation, the expression of lumican both in the epithelium and in the corneal stroma was comparable to that in the control group with higher parameters of epithelial expression after sodium hyaluronate administration. In the groups of endothelial-epithelial dystrophy, an increase in the intensity of expression was noted after sodium hyaluronate injections. The noted increase in the epithelial expression of lumican against the background of pronounced alteration is accompanied by its gradual decrease as the regeneration is completed. An important factor is its normal content in the corneal stroma, since both a sharp increase and low expression parameters are accompanied by a decrease in corneal transparency.

The cover photo shows different neovascularization types from the paper by Smid et al.

The cover photo shows different neovascularization types from the paper by Smid et al.

Prevalence of ophthalmic diseases in the population older than 50 years

To study the prevalence and age- and gender-related gradient of ophthalmic diseases (cataract, glaucoma, age-related macular degeneration, diabetic and hypertensive retinopathy) in the Russian population older than 50 years. A random population cohort (9360, aged 45-69 years) was examined in Novosibirsk in 2003/05 and re-examined in 2015/17 (the HAPIEE project). Ophthalmological parameters were studied in a random subsample (324 m/f, aged 55-84, 2015/17). Clinical and instrumental methods were applied to assess eye diseases: cataract, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy (DR), hypertensive retinopathy (HR) and other ophthalmic diseases. In the studied sample of men and women aged 55-84 years, the prevalence of cataract was 72.8%, AMD - 25.7%, glaucoma - 6.2%, DR - 2.1%, HR - 79.6%. The prevalence of other ophthalmic diseases (myopia, hyperopia, astigmatism, pterygium, pinguecula, dystrophy of cornea and retina, tumors and inflammatory diseases) was 13.5%. The frequency of cataract (p<0.001) and AMD (p=0.003) significantly increased with age. The frequency of glaucoma did not change substantially in the studied age range with insignificant increase in those older than 80 years (14.3%). The frequency of DR and HR were not consistently related to age. In the studied population sample of men and women aged 55-84 years (Novosibirsk), the prevalence of cataract and HR is high; the prevalence of AMD is similar to populations with moderate frequency of diseases; the frequency of glaucoma is close to populations with high prevalence of this disease. The frequency of cataract and AMD increased with age. There was no consistent age gradient of the frequency of glaucoma, DR and HR in the age range of 55-84 years.

Еfficacy of Combined Treatment of Epithelial and Endothelial Corneal Dystrophy Using Corneal Crosslinking and Automated Posterior Lamellar Keratoplasty

The purpose: to establish a combined approach to the treatment of patients with epithelial and endothelial cornea dystrophy (EED) based on a comparative study of the results of one-step and two-step methods. Patients and methods. The study included 75 patients (81 eyes) with corneal EED, who underwent surgical treatment at the Ufa Eye Research Institute from 2011 to 2016. The patients were divided into two groups — the main group consisted of 43 (46 eyes, 57 %) patients, who underwent the first stage of the CC before surgical treatment of EED, the second stage after 1–12 months — automated posterior lamellar keratoplasty (APLK). In the control group, isolated APLK was performed in 32 (35 eyes, 43 %) patients. Results. After CC (1–10 days) in the main group an increase in corneal thickness due to edema enhancement in the cornea stroma was observed in patients with stage I–III of the corneal EED. After 3 months, a decrease in corneal thickness was recorded in patients of the main group with I-II stages of the disease (p &lt; 0.05), after 6 months — in all stages of the corneal EED compared with the control group (p &lt; 0.05). According to optical coherence tomography (OCT), a decrease in the total cornea thickness in both зфешутеы groups was noted within 12 months after APLK: in the main group from 667 ± 65 μm initially to 594 ± 31 μm, in the control group, where there was a pronounced corneal edema from 787 ± 56 to 612 ± 67 μm. Conclusion. Corneal cross-linking in patients with I–III stages of corneal EED provides improvement of the cornea, manifested in reducing edema and its thickness. It allows to delay the implementation of the automated posterior lamellar keratoplasty without corneal deterioration in patients with stage I up to 6–12 months, in patients with stage II–III up to 3–6 months.

New approach to treating chronic dystrophic cornea diseases

The efficiency of the treatment of dry eye disease patients with keratopathy at a subconjunctival injection of 1 % sodium hyaluronate was studied. This review describes the functions of hyaluronic acid depending on its molecular weight. The performed study shows the necessity of using the injection form of sodium hyaluronate in the treatment of patients with dry eye disease.

THE PARTIAL DISCEMETOREXIS WITHOUT TRANSPLANTATION IN CASE OF ENDOTHELIAL DYSTROPHY OF CORNEA

During the last 20 years, the penetrating keratoplasty gave in its leading place to selective lamellar keratoplasty when pathologically altered layers of cornea are selectively replaced, including endothelium. The main technical task of all procedures of endothelial keratoplasty is an obligatory complete or almost complete post-operative adjacency of endothelial transplant to stroma of recipient. However, there are publications concerning resorption of edema in case of separation of endothelial transplant and even at its absence. The purpose of study. To analyze, on the basis of limited clinical observations, the results of partial discemetorexis (5.25 mm) without transplantation in patients with endothelial dystrophy of cornea (Fuchs).The materials and methods. The study was implemented concerning maximal correcting visual acuity, central thickness of cornea, density of endothelial cells and optical density of cornea, before, in one day, in one week, in 1, 3 and every 6 months after operation. The study covered 6 patients with Fuchs dystrophy (average age 63 ± 6,5 years) operated in 2015-2016 with period of observation neither less than 6 months. The visual acuity before operation in average made up to 0,32 ± 017 mkm, average central thickness of cornea - 677 ± 76 mkm. The native crystalline lens was present in 2 patients. The study was supported by ethical committee of the Helmholtz Moscow research institute of eyes diseases. The results. The resorption of edema of cornea occurred in 2 patients (33%), visual acuity increased from 0.45 to 0.6. In different periods density of endothelial cells varied from 549 to 689 kl/mm2. The central thickness of cornea decreased from 613 ± 33 mkm to 553 ± 15 mkm in 12 months after operation. Conclusion. The discemetorexis (5.25 mm) is more often efficient in case of availability of native crystalline lens, at earlier stages of dystrophy independently of patient's age. The discemetorexis ensures lower indices of maximal correcting visual acuity and density of endothelial cells and higher values of central thickness of cornea in comparison with DMEK. The indices of central thickness of cornea and optical density of cornea are exposed to fluctuations in different periods after discemetorexis (5.25 mm).

Quantitative metabolomic analysis of the human cornea and aqueous humor

Introduction Cornea is the outermost part of the eye supplied mostly by aqueous humor (AH). Therefore, the comparison of the metabolomic compositions of AH and cornea may help to determine which compounds are produced inside the cornea, and which penetrate into cornea from AH for intra-corneal consumption. Keratoconus (KC) is the most common form of the cornea dystrophy, and the analysis of KC corneas can unravel the metabolomic changes occurring in AH and cornea of KC patients.

THE PARTIAL DESCEMET'S STRIPPING WITH TRANSPLANTATION OF DESCEMET'S TRANSPLANT UNDER ENDOTHELIAL DYSTROPHY OF CORNEA

The DMEK technique is applied five times more rarely than DS(A)EK despite that DMEK provides higher functional result. The main causes are technical "convolution" of implementation, long period of training, accompanied by prolonged operations, higher reject control of donor's tissue, increased rate of dependency of endothelium and mismatch of transplant. Therefore, an efficient technique is needed similar to DMEK though simpler than DMEK.The purpose of study. To analyze the results of implantation of Descemet's transplant (DMET) in patients with endothelium dystrophy of cornea (Fuchs) on the basis of limited clinical observations.Material of study. In two years, DMET was implemented to 12 patients. The study included 6 patients with average age of 60±18 years (from 29 to 80 years). All female patients had primary endothelial dystrophy and one male patient had secondary endothelial dystrophy. The visual acuity prior to DMET in average made up to 0,2±0,2 (from 0,01 to 0,5). The average CTR according optical coherent eye tomography made up to 685±53 µm (from 622 to 749 µm). Results. Within available periods of observation, resorption of edema of cornea takes place in 4 patients (67%) and visual acuity increased from average 0,2±0,1 to 0,45±0,3. In various periods density of endothelium cells varied from 549 to 689 kl per mm2. The indices of optical coherent eye tomography decreased from pre-operational 685±53 µm to 553±15 µm. Conclusion. The results testify efficiency of DMET. The period of restoration of transparency of cornea can vary from 1 to 6 months. The indices of density of endothelium cells are inferior to indices after DMEK. Also, DMET is ineffective in case of secondary dystrophy and at most efficient on previously non-operated eyes.

TGFBI gene mutations analysis in Chinese families with corneal dystrophies

The aim of the present study was to examine the clinical features of three Chinese families with autosomal dominant corneal dystrophy (CD) and examine transforming growth factor‑β‑induced (TGFBI) gene mutations in these families. The TGFBI gene mutations were detected using direct sequencing of the whole coding regions and exon-intron boundaries of the TGFBI gene in the affected members from the three families with CD. The phenotypes of all affected individuals in the three families were observed via slit lamp examination. Sections of the cornea were used for biopsy following keratoplasty. Three types of TGFBI gene mutations, R124C, H626R and R124H, were detected in the patients from these three families. One family, with the R124C mutation, was diagnosed with lattice corneal dystrophy type 1, and the family with the H626R mutation was diagnosed with lattice corneal dystrophy type IIIB. The family with the R124H mutation was diagnosed with granular corneal dystrophy type2. The TGFBI gene mutations were considered underlying factors in the molecular mechanism underlying the pathogenesis of cornea dystrophy. Therefore, the detection of TGFBI gene mutations may be useful in the differential diagnosis of CD.

CLINICO-MORPHOLOGICAL SUBSTANTIATION OF CLASSIFICATION OF HORSES' ULCERATIVE KERATITIS

Ulcerative keratitis is common animal disease, which is reported from all over the world and has quite a wide spread in some regions. A number of typical symptoms of ulcerative keratitis of sick horses were investigated in current research. It was found that pathology of the eyes can be observed in animals of different age groups belonging to both genders. A group of 40 horses owned by private stables of Moscow and Moscow region was selected to conduct the study. Current research was a clinical and morphological investigation, which included both ophthalmic method and a set of cytological and bacteriological examinations. Ulcerative keratitis of horses can be either a result of a minor injury of the cornea caused by awn grasses, seed hulls, leaves, sawdust and further bacterial infection development, prolonged use of antibiotics/corticosteroids or when dystrophic cornea is infected due to the microcirculatory processes disorder.

Corneal imaging after treatment in dystrophic eyes (OCT, CM)

SummaryIn late follow‐up after lamellar or penetrating keratoplasty dystrophic corneas can develop again changes in the stroma. Advanced analysis of corneal morphology and morphometry based on OCT devices can predict such pathology. More specific imaging for early deposits delivers confocal microscopy. Analysis of corneal collagen layers, stromal keratinocytes and extracellular matrix deposits shows natural recurrence of the disease in transplanted cornea.

New histopathologic and ultrastructural findings in Reis-Bücklers corneal dystrophy caused by the Arg124Leu mutation of TGFBI gene.

BackgroundReis-Bücklers corneal dystrophy (RBCD) was consistently reported as a corneal dystrophy only affected Bowman’s layer and superficial corneal stroma, and superficial keratectomy was a recommendation surgery for treatment in literatures. The study reported new histopathological and ultrastructural findings in RBCD caused by the Arg124Leu mutation of transforming growth factor induced (TGFBI) gene in a four-generation Chinese pedigree.MethodsSubjects including eight patients and seven unaffected family members received slit-lamp biomicroscopy and photography. DNA was obtained from all subjects, and exons 4 and 11 to 14 of TGFBI gene were analyzed by polymerase chain reaction and the products were sequenced. Anterior segment optical coherence tomography (AS OCT) and in vivo confocal microscopy were conducted for ten eyes of five patients. Based on the results of AS OCT and in vivo confocal microscopy, deep anterior lamellar keratoplasty (DLKP) using cryopreserved donor cornea was applied for four eyes of four patients. Four lamellar dystrophic corneal buttons were studied by light and transmission electron microscopy, and TGFBI immunohistochemistry.ResultsEight patients had typical clinical manifestations of RBCD presenting recurrent painful corneal erosion starting in their early first decades, along with age-dependent progressive geographic corneal opacities. TGFBI sequencing revealed a heterozygous mutation, Arg124Leu in all eight patients. Anterior segment optical coherence tomography and in vivo confocal microscopy showed the dystrophic deposits involved not only in subepithelial and superficial stroma, but also in mid- or posterior stroma in four examined advanced eyes. Light microscopy showed Bowman’s layer was absent, replaced by abnormal deposits stain bright red with Masson’s trichrome. In superficial cornea, the deposits stacked and produced three to five continuous bands parallel to the corneal collagen lamellae. In mid- to posterior stroma, numerous granular or dot- like aggregates were heavily scattered, and most of them presented around the nuclei of stromal keratocytes. Transmission electron microscopy revealed the multiple electron-dense rod-shaped deposits aggregated and formed a characteristic pattern of three to five continuous bands in superficial cornea, which were similar to those seen under light microscopy. In mid- to posterior stroma, clusters of rod-shaped bodies were scattered extracellular or intracellular of the stromal keratocytes between the stromal lamellae suggesting the close relationship between mutated proteins and keratocyte.ConclusionsThe study offer evidences indicating DLKP is a viable treatment option for advanced RBCD to avoid recurrence, and the mutated TGFBIp in dystrophic corneas are of keratocytes origin.

Corneal High-Order Aberrations and Backscatter in Fuchs' Endothelial Corneal Dystrophy.

Suboptimal visual acuity after endothelial keratoplasty has been attributed to increased anterior corneal high-order aberrations (HOAs). In this study, we determined anterior and posterior corneal HOAs over a range of severity of Fuchs' endothelial corneal dystrophy (FECD). Cross-sectional study. A total of 108 eyes (62 subjects) with a range of severity of FECD and 71 normal eyes (38 subjects). All corneas were examined by using slit-lamp biomicroscopy to determine the severity of FECD versus normality. Fuchs' endothelial corneal dystrophy corneas were categorized as mild, moderate, or advanced according to the area and confluence of guttae and the presence of clinically visible edema. Normal corneas were devoid of any guttae. Wavefront errors from the anterior and posterior corneal surfaces were derived from Scheimpflug images and expressed as Zernike polynomials through the sixth order over a 6-mm diameter optical zone. Backscatter from the anterior 120 μm and posterior 60 μm of the cornea also was measured from Scheimpflug images and was standardized to a fixed scatter source. Variables were compared between FECD and control eyes by using generalized estimating equation models to adjust for age and correlation between fellow eyes. High-order aberrations, expressed as root mean square of wavefront errors, and backscatter of the anterior and posterior cornea. Total anterior corneal HOAs were increased in moderate (0.61±0.27 μm, mean ± standard deviation; P = 0.01) and advanced (0.66±0.28 μm; P = 0.01) FECD compared with controls (0.47±0.16 μm). Total posterior corneal HOAs were increased in mild (0.22±0.09 μm; P = 0.017), moderate (0.22±0.08 μm; P < 0.001), and advanced (0.23±0.09 μm; P < 0.001) FECD compared with controls (0.16±0.03 μm). Anterior and posterior corneal backscatter were higher for all severities of FECD compared with controls (P ≤ 0.02, anterior; P ≤ 0.001, posterior). Anterior and posterior corneal HOAs and backscatter are higher than normal even in early stages of FECD. The early onset of HOAs in FECD might contribute to the persistence of HOAs and incomplete visual rehabilitation after endothelial keratoplasty.

Characterization of abnormal epithelium after laser-assisted subepithelial keratectomy using in vivo confocal microscopy.

This study compared the abnormal corneal epithelium after laser-assisted subepithelial keratectomy (LASEK) with dystrophic cornea using in vivo using confocal microscopy (IVCM) and examined the effects of the abnormal epithelium on postoperative recovery of uncorrected distance visual acuity (UDVA) and sub-basal nerve plexus regeneration. The UDVA and wound healing were examined in 50 eyes of 25 patients undergoing LASEK at 1 week, 1 month, and 1 year postoperatively, including the visual acuity, slit lamp microscopy, and IVCM. After 1 week, the corneal epithelium was healed in all patients, but abnormal epithelial cells were detected in 33/50 patients using IVCM. Abnormal cells were limited to the surgical margin, and highly reflective granules were observed underneath. At 1 month and 1 year postoperatively, the abnormal epithelium was unchanged in size. At 1 year postoperatively, there were clear differences between the sub-basal nerve plexus in the normal and abnormal epithelium. At 1 month postoperatively, the UDVA was >1.0 in 88% of patients, which increased to 94% at 1 year, and there was no clear difference in the UDVA between abnormal (N = 33) and normal (N = 17) epithelium. After LASEK, abnormal epithelial cells may arise at the margin of the epithelial flap and persist 1 year postoperatively accompanied by poor regeneration of the sub-basal nerve plexus. However, this does not affect the UDVA postoperatively. The abnormal epithelium may be caused by residual necrotic basal cell debris on the epithelial basement membrane and abnormal neurotrophic metabolism between the corneal epithelium and nerve plexus.

Морфофункціональні зміни органа зору у зимівників української антарктичної станції «академік вернадський»

The study revealed that the Antarctic territory in the area of the Ukrainian Antarctic station "Academician Vernadsky" can be referred to the zone of the "super high", risk in developing ophthalmological pathology, caused by ultraviolet radiation. The results of the comprehensive dynamic study of 24 winterers of the XVI and XVII Ukrainian Antarctic expeditions (2011-2013) showed the developing of specific changes in the organ of vision under the exposure to the excessive natural ultraviolet radiation (UVR), such as parenchymatous-endothelial keratopathy, nuclear-posteriorcapsular phacopathy, maculopathy. Morphological changes were recorded using the cornea densitometry method: a decrease of the central cornea thickness by 14.3%, a decrease of the density and the number of endothelial cells of hexagonal type by 10.1% and 16.6%, respectively (P < 0.05). Using densitometry method, we detected morphological changes in the lens. Specifically, we found an increase of the optic lens density: in median zone by 10.1%, in maximal zone by 21.6%, in posterior part by 13.1%, P < 0.05. The results of densitometry recordings point to the development of local opacity in the posterior lens parts (in the nucleus and in the capsule). The data of the computed quantitative macula perimetry showed a significant decrease of light sensitivity of retina conicalis cells by 6 times (P < 0.05). The morphological signs of the endured acute solar retinopathy were found in more than 50% winterers. The revealed pathological changes can be considered as pre-, subclinical manifestations of the cornea dystrophy, cataracts and maculodystrophy, caused by specific action of the natural UVR, thus demanding the elaboration of the combined preventive measures.

Absence of beta‐amyloid in cortical cataracts of donors with and without Alzheimer's disease

AbstractPurpose Eye lenses from human donors with and without Alzheimer's disease (AD) were studied to evaluate the presence of amyloid in cortical cataract.Methods We obtained 39 lenses from 21 postmortem donors with AD and 15 lenses from age‐matched controls. For 17 donors, AD was clinically diagnosed by general physicians and for 4 donors the AD diagnosis was neuropathologically confirmed. As controls, 7 donors with pronounced cortical opacities and 8 donors with almost transparent lenses were selected. All lenses were photographed in a dark field stereomicroscope. Histological sections were analyzed using a standard and a more sensitive Congo red protocol, thioflavin staining and beta‐amyloid immunohistochemistry.Results Of the 21 donors with AD, 6 had pronounced bilateral cortical lens opacities and 15 only minor or no cortical opacities. Thioflavin, standard and modified Congo red staining were positive in the control brain tissues and in the dystrophic cornea. Beta‐amyloid immunohistochemistry was positive in the brain tissues but not in the cornea sample. Lenses from control and AD donors were, without exception, negative after Congo red, thioflavin, and beta‐amyloid immunohistochemical staining.Conclusion The absence of staining in AD and control lenses with the techniques employed lead us to conclude that there is no beta‐amyloid in lenses from donors with AD or in control cortical cataracts.

Ultrastructural 3D imaging of collagen fibrils and proteoglycans of macular dystrophy cornea

AbstractPurpose Macular cornea dystrophy (MCD) is an autosomal, recessive, genetic disorder, involving a gene on chromosome 6 that leads to aberrant keratan sulphate synthesis. Here we report ultrastructural 3D image analysis of collagen fibrils (CF) and proteoglycans (PGs) macular corneal dystrophy (MCD) corneas.Methods Three normal and three macular dystrophy (MCD) corneas were used for the study. The corneas were fixed in the 2.5% glutaraldehyde containing cuprolinic blue and processed for electron microscopy. 120 images were taken and used to construct 3D images of CF and PGs.Results 3D image analysis showed that the PGs were embedded within the collagen fibrils of the stroma. There were less electron dense particles within the CF of the MCD cornea compared to within the normal CF. The diameter of the CF in the anterior stroma was larger compared to the CF diameter in the posterior stroma. The PGs area in the anterior stroma was significantly larger compared to the PGs area in the middle and posterior stroma. The PGs around the degenerated keratocytes were much larger. PGs areas in the MCD cornea were significantly larger than the PGs areas of the normal cornea.Conclusion Ultrastructural 3D imaging provides detailed ultrastructural features of CF and PGs. A large aggregation of the PGs in the anterior stroma suggests that the degeneration of the anterior stroma was more severe compared to the degeneration of the middle and posterior stroma.