Stromal Dystrophy Research Articles

Efficacy of deep lamellar keratoplasty for the treatment of stromal corneal dystrophy

Objective To evaluate the efficacy of deep lamellar keratoplasty for the treatment of stromal corneal dystrophy. Methods The data of 59 eyes of 49 patients with stromal corneal dystrophy in this hospital from Jan.2012 to Dec.2018 were analyzed retrospectively.All cases were treated with deep lamellar keratoplasty.The follow-up time was 6 months-4 years.The corneal graft and the complications of intra-operation and post-operation were observed. Results The corneal graft remained clear in all cases after surgery. The best corrected visual acuity (BCVA) postoperatively was 0.3 in 8 eyes, 0.4-0.6 in 40 eyes, 0.6-0.8 in 11 eyes. Intraoperative complications included perforation of descemet’s membrane in 5 eyes, postoperative temporary elevation of intraocular pressure in 4 eyes, descemet’s membrane striae in 6 cases and recurrence of primary disease in 3 eyes. No reject reaction occurred after keratoplasty. Conclusion Deep lamellar keratoplasty is a safe and effective method for the treatment of stromal corneal dystrophy. Key words: Keratoplasty, lamellar, deep; Dystrophy, corneal, Stromal

Corneal biomechanics and intraocular pressure assessment after penetrating keratoplasty for non keratoconic patients, long term results

BackgroundTo evaluate corneal biomechanical properties by the Ocular Response Analyzer (ORA) in non keratoconic patients underwent penetrating keratoplasty (PK).MethodsCorneal hysteresis (CH), corneal resistance factor (CRF), Goldmann- correlated intraocular pressure (IOPg), cornea-compensated IOP (IOPcc) using the ORA, and central graft thickness (CGT) were measured in 30 eyes at least two years after penetrating keratoplasty for non keratoconic indications. IOP using the Goldmann applanation tonometer (GAT) was also obtained after compensation for graft thickness and astigmatism.ResultsThe mean age of patients was 33.1 ± 10.13 years; indications for PK were herpetic corneal scar (53.3%), corneal stromal dystrophy (23.3%), traumatic corneal opacity (10%), chemical corneal opacity (6.7%), and Fuchs endothelial dystrophy (6.7%). Mean CH and CRF were 8.52 ± 1.81 mmHg, and 8.56 ± 1.59 mmHg, respectively. Mean CGT was 532.43 ± 30 μm. Mean IOP GAT, IOPg, and IOPcc were 11.88 ± 3.66, 14.64 ± 4.08, and 17.27 ± 4.60 mmHg, respectively (P < 0.001). No significant association was found between CGT and IOP readings obtained using either the ORA or GAT. There were significant negative association between CH with both IOP GAT and IOPcc, while CRF had significant positive association with IOPg.ConclusionAfter penetrating keratoplasty for non keratoconic patients, graft biomechanics does not return to average values even 2 years after the operation; moreover, intraocular pressure measurement with ORA gives higher values than thickness compensated GAT.

Risk factors for graft failure after penetrating keratoplasty.

The objective of our study was to define principal risk factors for graft failure in patients who underwent penetrating keratoplasty (PK).Retrospective data obtained from a cohort of 895 penetrating keratoplasties performed between 2001 and 2006 were analysed. Recipient related factors, graft characteristics, and surgical technique were assessed in a univariate analysis and with a multivariate proportional hazard model to detect principal risk factors for definitive graft failure.Multivariate analysis showed clear significance for diagnosis and number of previous grafts and border line significance for the oldest donor age group. Patients with keratoconus had the best 10-year survival estimate (95%), followed by endothelial and stromal dystrophies (both 55%), infectious leukomas (49%), trauma (33%) and chemical burns (14%). Primary PK grafts had a survival rate of 81%, second grafts of 33% and third or more grafts of 16%. Overall 10-year survival estimate based on univariate analysis was found to be 65%.In conclusion, we found that primary diagnosis and previous graft failures in the recipient are the most important risk factors of graft failure after a PK.

Epithelial Dystrophies of the Cornea

In 2015, the first revision of the international classification of corneal dystrophies (IC3D) has been published. According to this latest version of the IC3D the dystrophies of the cornea are divided into · epithelial and subepithelial dystrophies,. · epithelial-stromal TGFBI dystrophies,. · stromal dystrophies, and. · Descemet-membrane and endothelial dystrophies.. This article summarizes the epithelial and subepithelial dystrophies of the cornea, which, according to IC3D are the following: · epithelial basement membrane dystrophy (EBMD),. · epithelial recurrent erosion dystrophy (ERED),. · subepithelial mucinous corneal dystrophy (SMCD),. · Meesmann corneal dystrophy (MECD),. · Lisch epithelial corneal dystrophy (LECD),. · gelatinous drop-like corneal dystrophy (GDLD).. The main problem concerning almost all dystrophies of the corneal epithelium are epithelial defects (erosion) associated with pain, epiphora and red eyes. In addition, all dystrophies of the epithelium tend to relapse.While therapy is usually initiated with topical therapeutics, in the course of the disease invasive procedures like phototherapeutic keratectomy (PTK) (possibly with the administration of mitomycin C) or in severe cases even keratoplasty (preferably as deep anterior lamellar keratoplasty; DALK) have to be used. Due to the origin of the disease in the epithelial stem cells at the limbus, the replacement of these cells can also be discussed.

Recurrent corneal erosion: a comprehensive review.

PurposeTo comprehensively review the literature regarding recurrent corneal erosion (RCE) and to present treatment options and recommendations for management.OverviewRCE usually presents with sharp, unilateral pain upon awakening, in an eye with an underlying basement membrane dystrophy, prior ocular trauma, stromal dystrophy or degeneration, or prior surgery for refractive errors, cataracts, or corneal transplantation. Making the correct diagnosis requires a careful slit-lamp examination of both eyes coupled with a high degree of suspicion. Several treatments are commonly used for RCE but new therapies have been introduced recently. Conservative treatment consists of antibiotic and preservative-free lubricating drops, with topical cycloplegics and oral analgesics to control pain. Patients who are unresponsive to these therapies may benefit from therapeutic bandage contact lenses (BCL). Newer therapies include oral matrix metalloproteinase (MMP) inhibitors, blood-derived eye drops, amniotic membrane graft application, and judicious application of topical corticosteroids. Once the epithelium is healed, a course of hypertonic saline solution and/or ointment can be used. Surgical procedures may be performed in patients who fail conservative therapy. Punctal occlusion with plugs increases the tear film volume. Epithelial debridement with diamond burr polishing (DBP), anterior stromal puncture (ASP), or alcohol delamination should be considered in selected patients. DBP can be used for patients with basement membrane dystrophies and is the preferred treatment overall due to a low recurrence rate. ASP can be used for erosions outside the central visual axis. Excimer laser phototherapeutic keratectomy is an attractive option in eyes with central RCE since it precisely removes tissue while preserving corneal transparency. In patients with RCE who are also candidates for refractive surgery, photorefractive keratectomy can be considered.SummaryNewly introduced therapies for RCE enable therapy to be individualized and lower the recurrence rate.

Indications and Surgical Techniques for Corneal Transplantation at a Tertiary Referral Center.

Purpose:The study aimed to review the indications and techniques for corneal transplantation at a tertiary referral center over a 5-year period.Methods:Records of patients who underwent corneal transplantation at Khalili Medical Center, Shiraz, Iran from September, 2012 to September, 2017 were reviewed.Results:A total of 1149 eyes of 956 patients underwent corneal transplantation. The most common indication was infectious corneal ulcers (n = 296, 25.8%), followed by keratoconus (n = 243, 21.1%), bullous keratopathy (n = 219, 19.1%), failed grafts (n = 117, 10.2%), non-herpetic corneal scars (n = 113, 9.8%), corneal stromal dystrophies (n = 33, 2.9%), pellucid marginal degeneration (n = 31, 2.7%), and trauma (n = 26, 2.3%); other indications included thin descemetocele, post-herpetic corneal scar, endothelial corneal dystrophies, anterior segment dysgenesis, corneal ectasia after laser in situ keratomileusis, and corneal fibrosis. Corneal transplantation techniques included penetrating keratoplasty (PKP, n = 789, 68.7%), deep anterior lamellar keratoplasty (DALK, n = 187, 16.3%), Descemet's stripping automated endothelial keratoplasty (n = 171, 14.9%), and keratolimbal allograft (n = 2, 0.1%) in descending order. In children (aged ≤18 years), the most common indication was keratoconus (n = 32, 41.6%), and the most common technique was PKP (n = 50, 64.9%). In patients aged 19-27 years, the most common indication was keratoconus (n = 89, 64.5%), and the most common technique was PKP (n = 75, 54.4%).Conclusion:Infectious corneal ulcer was the most common indication, and PKP was the most prevalent technique in patients undergoing corneal transplantation. DALK was an emerging alternative surgical treatment in patients with corneal disorders in which corneal endothelium is spared.

Vision-Related Quality of Life Before and After Deep Anterior Lamellar Keratoplasty.

To determine changes in the vision-related quality of life in patients undergoing deep anterior lamellar keratoplasty (DALK) by using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Thirty-five patients who were scheduled for DALK between March 1, 2013, and March 1, 2014 were asked to complete the NEI VFQ-25. NEI VFQ-25 was administered again at 6 months and at 1 year postoperatively. Data on patients' age, sex, preoperative diagnosis, preoperative and postoperative best-corrected visual acuity, and postoperative astigmatism were recorded. Successful DALK with the Anwar big bubble technique was achieved in 23 of 35 (65.7%) patients. The indications for surgery were keratoconus in 15 patients (62.2%), stromal corneal dystrophies in 4 (17%), and corneal scar in 4 (17%). The mean preoperative NEI VFQ-25 composite score (55.2±19.7) improved significantly (76.9±11.6) at 6 months after DALK and continued to improve (84.3±6.6) at 1 year postoperatively (Friedman test, P=0.001). All NEI VFQ-25 subscale item scores increased significantly after surgery. The patients' age was significantly correlated with the NEI VFQ-25 subscale score of mental health at 6 month and at 1 year postoperatively (r=0.92, P=0.008 and r=0.94, P=0.005, respectively). There was a negative relationship between postoperative astigmatism at 1 year and NEI VFQ-25 ocular pain, social functioning, peripheral vision, and mental health subscale scores (r=-0.76, P=-0.07; r=-0.53, P=0.2; r=-0.53, P=0.27; r=-0.80, P=0.05). Vision-related quality of life improved significantly after DALK and continued to improve after suture removal.

Neurotrophic Keratitis: Definition, clinical presentation and diagnosis

Neurotropic Keratitis is a non‐healing or repeated break down of corneal epithelium associated with degenerative changes resulting from impaired corneal innervation. Later complications such as infection scarring and perforation can follow. A reduced or absent corneal sensation is the hallmark of the disease.Patients present with dryness, photophobia and inability to read for prolonged duration hich is worse by computer work or air draft.Signs are divided into 2 parts: Signs related to the disease process such as corneal epithelial irregularity and clouding, reduced tear break up time and superficial punctate keratitis mostly inferior, Later persistent epithelial defect, corneal ulcers with rolled edges and loose epithelium surrounding the edges which can later develop infection, melting, scarring or perforation. Signs related to the underlying cause such as lagophthalmous and reduced blink reflex, signs of previous herpetic keratitis with scarring, vascularization and or patches of iris atrophy. Stromal dystrophy or beaded corneal nerves, advanced diabetic retinopathy or retinal laser marks.Diagnosis includes clinical presentation, duration of non‐healing epithelial defect and measuring corneal sensation with Coche‐Bonnet test.

Long-term clinical outcome of femtosecond laser-assisted lamellar keratectomy with phototherapeutic keratectomy in anterior corneal stromal dystrophy

PurposeTo evaluate long-term outcome of femtosecond laser-assisted lamellar keratectomy (FLK) with phototherapeutic keratectomy (PTK) in patients with anterior corneal stromal dystrophies.MethodsA total of 10 eyes from seven patients who underwent...

Effect of position-specific single-point mutations and biophysical characterization of amyloidogenic peptide fragments identified from lattice corneal dystrophy patients.

Corneal stromal dystrophies are a group of genetic disorders that may be caused by mutations in the transforming growth factor β-induced (TGFBI) gene which results in the aggregation and deposition of mutant proteins in various layers of the cornea. The type of amino acid substitution dictates the age of onset, anatomical location of the deposits, morphological features of deposits (amyloid, amorphous powder or a mixture of both forms) and the severity of disease presentation. It has been suggested that abnormal turnover and aberrant proteolytic processing of the mutant proteins result in the accumulation of insoluble protein deposits. Using mass spectrometry, we identified increased abundance of a 32 amino acid-long peptide in the 4th fasciclin-like domain-1 (FAS-1) domain of transforming growth factor β-induced protein (amino acid 611–642) in the amyloid deposits of the patients with lattice corneal dystrophies (LCD). In vitro studies demonstrated that the peptide readily formed amyloid fibrils under physiological conditions. Clinically relevant substitution (M619K, N622K, N622H, G623R and H626R) of the truncated peptide resulted in profound changes in the kinetics of amyloid formation, thermal stability of the amyloid fibrils and cytotoxicity of fibrillar aggregates, depending on the position and the type of the amino acid substitution. The results suggest that reduction in the overall net charge, nature and position of cationic residue substitution determines the amyloid aggregation propensity and thermal stability of amyloid fibrils.

Pathophysiological Significance of Dermatan Sulfate Proteoglycans Revealed by Human Genetic Disorders.

The indispensable roles of dermatan sulfate-proteoglycans (DS-PGs) have been demonstrated in various biological events including construction of the extracellular matrix and cell signaling through interactions with collagen and transforming growth factor-β, respectively. Defects in the core proteins of DS-PGs such as decorin and biglycan cause congenital stromal dystrophy of the cornea, spondyloepimetaphyseal dysplasia, and Meester-Loeys syndrome. Furthermore, mutations in human genes encoding the glycosyltransferases, epimerases, and sulfotransferases responsible for the biosynthesis of DS chains cause connective tissue disorders including Ehlers-Danlos syndrome and spondyloepimetaphyseal dysplasia with joint laxity characterized by skin hyperextensibility, joint hypermobility, and tissue fragility, and by severe skeletal disorders such as kyphoscoliosis, short trunk, dislocation, and joint laxity. Glycobiological approaches revealed that mutations in DS-biosynthetic enzymes cause reductions in enzymatic activities and in the amount of synthesized DS and also disrupt the formation of collagen bundles. This review focused on the growing number of glycobiological studies on recently reported genetic diseases caused by defects in the biosynthesis of DS and DS-PGs.

In vivo confocal microscopy of pre-Descemet corneal dystrophy associated with X-linked ichthyosis: a case report

BackgroundPre-Descemet corneal dystrophy (PDCD) is characterized by the presence of numerous, tiny, polymorphic opacities immediately anterior to Descemet membrane, which is a rare form of corneal stromal dystrophy and hard to be diagnosed. In vivo confocal microscopy (IVCM) is a useful tool to examine the minimal lesions of the cornea at the cellular level. In this article, we report a rare case of PDCD associated with X-linked ichthyosis and evaluate IVCM findings.Case presentationWe present a 34-year-old male Chinese patient with PDCD associated with X-linked ichthyosis. Slit-lamp biomicroscopy showed the presence of tiny and pleomorphic opacities in the posterior stroma immediately anterior to Descemet membrane bilaterally. IVCM revealed regular distributed hyperreflective particles inside the enlarged and activated keratocytes in the posterior stroma. Hyperreflective particles were also observed dispersedly outside the keratocytes in the anterior stroma. Dermatological examination revealed that the skin over the patient’s entire body was dry and coarse, with thickening and scaling of the skin in the extensor side of the extremities. PCR results demonstrated that all ten exons and part flanking sequences of STS gene failed to produce any amplicons in the patient.ConclusionsIVCM is useful for analyzing the living corneal structural changes in rare corneal dystrophies. We first reported the IVCM characteristics of PDCD associated with X-linked ichthyosis, which was caused by a deletion of the steroid sulfatase (STS) gene, confirmed by gene analysis.

Mice, double deficient in lysosomal serine carboxypeptidases Scpep1 and Cathepsin A develop the hyperproliferative vesicular corneal dystrophy and hypertrophic skin thickenings

Vasoactive and mitogenic peptide, endothelin-1 (ET-1) plays an important role in physiology of the ocular tissues by regulating the growth of corneal epithelial cells and maintaining the hemodynamics of intraocular fluids. We have previously established that ET-1 can be degraded in vivo by two lysosomal/secreted serine carboxypeptidases, Cathepsin A (CathA) and Serine Carboxypeptidase 1 (Scpep1) and that gene-targeted CathAS190A /Scpep1-/- mice, deficient in CathA and Scpep1 have a prolonged half-life of circulating ET-1 associated with systemic hypertension. In the current work we report that starting from 6 months of age, ~43% of CathAS190A /Scpep1-/- mice developed corneal clouding that eventually caused vision impairment. Histological evaluation of these mice demonstrated a selective fibrotic thickening and vacuolization of the corneas, resembling human hyperproliferative vesicular corneal stromal dystrophy and coexisting with a peculiar thickening of the skin epidermis. Moreover, we found that cultured corneal epithelial cells, skin fibroblasts and vascular smooth muscle cells derived from CathA/Scpep1-deficient mice, demonstrated a significantly higher proliferative response to treatment with exogenous ET-1, as compared with cells from wild type mice. We also detected increased activation level of ERK1/2 and AKT kinases involved in cell proliferation in the ET-1-treated cultured cells from CathA/Scpep1 deficient mice. Together, results from our experimental model suggest that; in normal tissues the tandem of serine carboxypeptidases, Scpep1 and CathA likely constitutes an important part of the physiological mechanism responsible for the balanced elimination of heightened levels of ET-1 that otherwise would accumulate in tissues and consequently contribute to development of the hyper-proliferative corneal dystrophy and abnormal skin thickening.

An Interesting Case of Granular Corneal Dystrophy Type 1

Corneal epithelial-stromal and stromal dystrophies are a group of inherited disorders of the cornea that are caused by progressive accumulation of deposits within the layers of the cornea. Most dystrophies previously considered stromal are now classified as either epithelial-stromal dystrophies or stromal dystrophies. These deposits are not caused by inflammation, infection, or trauma, but by genetic mutations that lead to transcription of aberrant proteins resulting in the accumulation of insoluble material within the cornea. Hereby author intends to report an interesting case of granular corneal dystrophy type 1.

Confocal microscopy findings in corneal dytrophies

SummaryCorneal confocal microscopy in vivo is a diagnostic method that uses 670 nm laser beam to visualize the structures of the cornea with an accuracy of 1 μm and visualization of single cells with 63× magnification. Proper diagnosis of corneal diseases is often difficult. The use of confocal microscopy for the in vivo analysis of the microarchitecture of the cornea can provide rapid and highly specific differentiation of corneal pathologies.The aim of the course is to acquaint participants with the method – corneal confocal microscopy in vivo and to present its utility in diagnosis and management of corneal dystrophies. Course consists of description of epithelial‐basal membrane dystrophies, Bowman membrane dystrophies, stromal and endothelial dystrophies with respect to their typical histological features, differential diagnosis, evaluation and qualification for surgery and follow‐up with detection of possible recurrences and post‐surgical complications.

Disorders of the extracellular matrix in epithelial-stromal and stromal corneal dystrophies

The human cornea is rich in extracellular matrix. The stroma constitutes the main thickness of the cornea, which consists of collagens and proteoglycans mainly. The epithelial-stromal and stromal dystrophies of the cornea are either autosomal dominant or recessive inherited disorders, which are unrelated to inflammation or trauma. The diseases can manifest in each layer of the cornea, but in most cases the corneal stroma is affected. Generally, they develop in childhood or young adulthood but the diagnosis is only possible when clinical signs (epithelial erosions, decreased visual acuity, photophobia) develop. The different protein aggregates (hyaline, amyloid, crystalline) deposited in the corneal layers result in mild or advanced corneal opacity and loss of the corneal transparency due to disorganisation of the extracellular matrix. In some of the corneal dystrophies the keratane sulphate proteoglycan looses its function which results in a loss of the regular interfibrillar spacing. Due to the severe corneal opacity patients may need corneal transplantation. Orv. Hetil., 2016, 157(33), 1299-1303.

Intraoperative Optical Coherence Tomography In Deep Anterior Lamellar Keratoplasty

Like penetrating keratoplasty (pKPL), deep anterior lamellar keratoplasty (DALK) is a standard treatment for keratoconus and stromal corneal dystrophies. Intraoperative optical coherence tomography permits live or real-time monitoring during surgery, especially if it is necessary to estimate distances or if the anterior chamber view is limited. Review of literature from PUBMED and our own clinical and experimental data. Key words were "intraoperative Optical Coherence Tomograph", "DALK", "Deep anterior lamellar keratoplasty" and "iOCT". The time frame was set from 2005 to 2016. All surgical steps were visualisable by intraoperative OCT during DALK surgery. Intraoperative OCT permits depth estimation during deep needle insertion and allows the visualisation of intraoperative interface fluid. Intraoperative OCT facilitates standardisation during several steps of DALK. Future prospective studies should concentrate on the safety profile of intraoperative OCT-guided DALK compared to DALK without intraoperative monitoring.

Changing indications and techniques for corneal transplantations at a tertiary referral center in Turkey, from 1995 to 2014

BackgroundIndications for corneal transplantation in developed and developing nations differ according to the different spectrum of corneal disease in each country.ObjectiveThe purpose of this study is to analyze the changing indications and surgical techniques for corneal transplantation over the past 20 years at a tertiary referral center in Turkey.MethodsWe retrospectively reviewed the records of patients who underwent keratoplasty from January 1995 to December 2014 (between 1995 and 2004, period 1, and between 2005 and 2014, period 2). Patients’ demographic data, indications for corneal transplantation, and the type of surgery were recorded.ResultsThe number of keratoplasties performed ranged from 548 in period 1 to 782 in period 2. Between 1995 and 2004, the leading indications were keratoconus (34.1%), bullous keratopathy (17%), and non-herpetic corneal scar (13.3%), and between 2005 and 2014, they were keratoconus (33.8%), corneal stromal dystrophy (14.2%), and bullous keratopathy (12.7%). All the keratoplasties performed in the 1995–2004 period were penetrating keratoplasty (PKP). During the period 2005–2014, PKP accounted for 93%, automated lamellar keratoplasty 5.8%, and deep anterior lamellar keratoplasty 1.2% of all corneal transplantations.ConclusionKeratoconus was the leading indication for keratoplasty in both periods. In the 2005–2014 period, corneal stromal dystrophy increased significantly. All the keratoplasties performed in period 1 and 93% of all keratoplasties performed in period 2 were PKP.

PH Induced Conformational Transitions in the Transforming Growth Factor β-Induced Protein (TGFβIp) Associated Corneal Dystrophy Mutants.

Most stromal corneal dystrophies are associated with aggregation and deposition of the mutated transforming growth factor-β induced protein (TGFβIp). The 4th_FAS1 domain of TGFβIp harbors ~80% of the mutations that forms amyloidogenic and non-amyloidogenic aggregates. To understand the mechanism of aggregation and the differences between the amyloidogenic and non-amyloidogenic phenotypes, we expressed the 4th_FAS1 domains of TGFβIp carrying the mutations R555W (non-amyloidogenic) and H572R (amyloidogenic) along with the wild-type (WT). R555W was more susceptible to acidic pH compared to H572R and displayed varying chemical stabilities with decreasing pH. Thermal denaturation studies at acidic pH showed that while WT did not undergo any conformational transition, the mutants exhibited a clear pH-dependent irreversible conversion from αβ conformation to β-sheet oligomers. The β-oligomers of both mutants were stable at physiological temperature and pH. Electron microscopy and dynamic light scattering studies showed that β-oligomers of H572R were larger compared to R555W. The β-oligomers of both mutants were cytotoxic to primary human corneal stromal fibroblast (pHCSF) cells. The β-oligomers of both mutants exhibit variations in their morphologies, sizes, thermal and chemical stabilities, aggregation patterns and cytotoxicities.

Role of Decorin Core Protein in Collagen Organisation in Congenital Stromal Corneal Dystrophy (CSCD).

The role of Decorin in organising the extracellular matrix was examined in normal human corneas and in corneas from patients with Congenital Stromal Corneal Dystrophy (CSCD). In CSCD, corneal clouding occurs due to a truncating mutation (c.967delT) in the decorin (DCN) gene. Normal human Decorin protein and the truncated one were reconstructed in silico using homology modelling techniques to explore structural changes in the diseased protein. Corneal CSCD specimens were also examined using 3-D electron tomography and Small Angle X-ray diffraction (SAXS), to image the collagen-proteoglycan arrangement and to quantify fibrillar diameters, respectively. Homology modelling showed that truncated Decorin had a different spatial geometry to the normal one, with the truncation removing a major part of the site that interacts with collagen, compromising its ability to bind effectively. Electron tomography showed regions of abnormal stroma, where collagen fibrils came together to form thicker fibrillar structures, showing that Decorin plays a key role in the maintenance of the order in the normal corneal extracellular matrix. Average diameter of individual fibrils throughout the thickness of the cornea however remained normal.