bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence and risk factors for refractive errors among the university students of Iran
Authors: YEKTA AA , GHASEMI S , KHABAZKHOOB M , OSTADIMOGHADDAM H , YEKTA R , DERAKHSHAN A , HERAVIAN J , AZIMI A , RASHID TORABI M
Published: August 2012

Purpose To determine the prevalence and risk factors of refractive errors in Iranian university students.

Methods In a randomized study, of 424 selected students from the six schools of Mashhad University of Medical Sciences (MUMS), 406 of them participated in the study (response rate: 95.7%). Refractive errors were corrected using auto refraction checked by retinoscopy and subjective refraction. Myopia defined as spherical equivalent (SE) refraction ‐0.50 dioptre (D) or worse, hyperopia as SE of +0.50D or more, and astigmatism as cylinder –1.0D or worse.

Results The prevalence of myopia, hyperopia and astigmatism were 38.4%, 13.8% and 12.8% among the university students respectively. The prevalence of spherical refractive errors were different in males and females (P=0.038).

Conclusion The results of this study indicated that nearly two‐third of the university students have refractive errors. Myopia appears to be more common among highly educated persons and unversity students are at high risk for it.
Blood basement membrane alterations in human retinal microaneurysms during aging
Authors: RUBERTE J , LOPEZ‐LUPPO M , RAMOS D , MENDES‐JORGE L , NAVARRO M , CARRETERO A , RODRIGUEZ‐BAEZA A , NACHER V
Published: August 2012

Purpose Different studies indicates that the presence of retinal microaneurysms, dilations of the capillaries which often develop as gross outpouchings of the vessel wall, appears during human aging. However, little is known about the mechanisms involved in the development of these structures. The aim of this study was to examine whether basement membrane protein expression and organization changes during the formation of retinal microaneuryms.

Methods Human retinas were obtained from 17 donors: 14 old‐donors and 3 middle‐aged donors. Basement membrane proteins (collagen IV, laminin, fibronectin, nidogen), perlecan and MMP‐9 expression were analyzed in paraffin sections and whole‐mount formalin fixed retinas using immunohistochemistry and laser‐confocal microscopy. The structure of basement membrane was analyzed by TEM.

Results Microaneurysms were present in all the retinas obtained from old donors but were absent in the retinas obtained from midle‐aged donors. Microaneurysms were classified as Type I (early stage) and Type II (advanced stage). We observed that all basement membrane proteins increased its expression in Type I microaneurysms, but they disminished in Type II microaneuryms. In addition, MMP‐9 was strongly expressed in microaneurysms producing basement membrane disorganization.

Conclusion Collagen IV, laminin, fibronectin, nidogen and perlecan were increased in Type I microaneurysm basement membrane. A concommitant expression of MMP‐9 could explain the disorganization of blood basement membrane components.
Normative data for macular thickness by Spectral Domain OCT in healthy children.
Authors: PEREZ GARCIA D , PINILLA I , IBANEZ ALPERTE J , ASCASO F , CRISTOBAL JA
Published: August 2012

Purpose To evaluate normal values of macular thickness and macular volumen in children without any known retinal disease, using Spectral Domain Coherence Tomography.

Methods This study envolved 323 eyes from 323 pediatric patients (138 male,185 female) with ages between 3 and 14 years. All patients underwent a detailed eye examination, including best corrected visual acuity, cover test, slit lamp and fundus examination and refraction after pupillary dilation. Spectralis OCT scanning were performed by the same operador on all subjects.

Results The 323 subjects had a mean age of 8,3 years (3‐14) and the average spherical equivalent value was 0,08 ± 0,14 (‐0,06, 0,22). Foveal thickness was 217,08 ± 3,23 (214, 220) for children aged 3‐5, 219,16 ± 3,27 (216, 222) for children 6‐8 , 215,25 ± 2,97 (212, 218) for children between 9‐11 years, and 222,83 ± 3,53 (219, 226) for subjects aged 12‐14 years. There was no significant difference with age o gender. Macular volume values are also presented.

Conclusion Our study reports normative data for macular thickness in healthy pediatric patients with SD‐OCT . Values obtained may be useful in screening for retinal disease in childhood.
Hypoxia Inducible Factor‐1a (HIF‐1a) and Heat Shock Proteins 90, 70 (HSP 90, 70) expression in ocular pterygium and normal conjunctiva.
Authors: PAGOULATOS D , PHARMAKAKIS N , ARGYROPOULOU A , ASSIMAKOPOULOU M
Published: August 2012

Purpose Research has shown that HSPs participates in preserving HIF‐1a function. In this study, HIF‐1a, and HSP90, 70, expression and immunolocalization in ocular pterygium and normal conjunctiva samples was examined.

Methods Fifty nine samples of ocular pterygium and twenty samples of normal conjunctiva, surgically removed, were tested with immunohistochemistry, immunofluorecense and western blot analysis.

Results Between pterygium specimens and normal conjuctiva specimens, significant differences were observed in the expressions of proteins HSP90 (p=0.002), HIF‐1a (p=0.048). No significant differences were found in the expressions of HSP70 in ocular pterygium when compared to the normal conjunctiva.

Conclusion These data provide molecular evidence that Hypoxia‐Inducible Factor‐1a and HSP90 may have a role to play in pterygium pathogenesis.
Comparative endonasal analysis of the inferior lateral wall of the nasal fossae in adults with and without epiphora
Authors: HUBAULT B , VALLE D , MEROL JC , ARNDT C , DUCASSE A
Published: August 2012

Purpose The development of endonasal dacryocysto‐rhinostomia is associated with the advent of nasal video endoscopia which enables a perfect visualization of the surgical site. As the inferior turbinate bones are close to the lacrimonasal duct orifice at the level of Hasner’s valvula, anatomic variations of endonasal structures could be associated with the occurrence of epiphora.

Methods The results of nasal endoscopia between a group of adult patients with epiphora (n=35) and a control group of patients (n=19) without epiphora were compared. The endoscopic examination concentrated on changes of the inferior part of the nasal fossae and particularily on the inferior meatus and inferior turbinate bones. A non parametric Mann Whitney test was performed to compare the findings in the two groups.

Results Neither the edema of the inferior turbinate bones nor the visibility of the inferior meatus were associated with epiphora due to lacrimonasal duct stenosis (avec p >0.05). It appeared that there are major anatomic variations of the nasal fossae between two patients but also between either side of the same patient. The lack of difference observed between the two groups of patients could be due to the major anatomic variations observed in the nasal fossae.

Conclusion No particular correlation between anatomical changes of the lateral wall of the nasal fossae and the existence of lacrimonasal duct stenosis was found. However it remains essential to perform preoperative nasal endoscopy in order to detect a possible cause of lacrimonasal duct stenosis and thus evaluate the feasibility of surgery.
Changes in meibography in pediatric blepharokeratoconjunctivitis
Authors: BOLDIN I , RABENSTEINER DF , WOLTSCHE N , PöSCHL E:M: , HORWATH‐WINTER J
Published: August 2012

Purpose Pediatric blepharokeratoconjunctivitis is an underrecognized and poorly defined disorder. Few details are known about its underlying etiology because children are less cooperative with intensive examination. Nevertheless the meibomian gland dysfunction seems to play an important role in the etiology. Non‐contact Meibography can achieve a non‐invasive investigation of the meibomian glands inside the tarsal plates of the eyelids. The purpose of this study was to investigate meibomian gland morphology in pediatric blepharokeratoconjunctivitis by non‐contact infrared Meibography.

Methods The study group included 10 children (20 eyes) suffering from pediatric blepharokeratoconjunctivitis. Subjective symptoms of ocular discomfort, conjunctival and corneal involvement were recorded. The lid margins were evaluated and non‐contact Meibography was performed. Partial or complete loss of the meibomian glands and the presence of tortuosity were checked.

Results All patients reported ocular discomfort as well as lid margin, conjunctival, and corneal involvement. The mean age of the study population was 8 years (2‐16 years) and 60% were female. In 8 children (out of 10) meibography revealed partial or complete drop out of meibomian glands in the upper or lower tarsal plate but more frequently in the lower tarsal plate, also abnormal tortuosity of the meibomian glands in the upper eyelid was found.

Conclusion Our investigations showed that pediatric blepharokeratoconjunctivitis can be associated with drop out or abnormal tortuosity of meibomian glands evaluated with meibography.
Evaluation of limbal stem cell deficiency: a new diagnostic tool based on keratin 13 immunostaining in corneal impression cytology
Authors: POLI M , JUSTIN V , DAMOUR O , BURILLON C
Published: August 2012

Purpose The aim of this study was to develop a validated, reliable and minimally invasive technique for diagnosing limbal stem cell deficiency (LSCD) using immunocytochemical detection of conjunctival and corneal keratins on epithelial cells collected by impression cytology (IC).

Methods After validation of the labelling techniques on a cohort of ten healthy control patients, keratins K12, K13 and K19 were labelled on corneal IC of ten eyes suspected of LSCD. Positive scores for the conjunctival markers K13/K19, combined with the rarity of the corneal marker K12, were diagnostic proof of LSCD.

Results IC is a reliable and noninvasive technique for collecting epithelial cells. The labelling validation phase eliminated K3 labelling due to lack of corneal specificity. Among the patients with suspected LSCD, nine samples were diagnosed with LSCD, which was severe (K12 negative) in eight cases and mild (K12 positive) in one case. One sample could not be analysed due to insufficient cells.

Conclusion The immunocytochemical search for the K13/K19 pair using corneal IC provides a simple and reliable method for diagnosing LSCD, while the level of K12 provides a score of disease severity. On the other hand, we question the corneal specificity of K3 as conventionally established. Finally, to our knowledge, this is the first study detecting K13 on a conjunctival IC specimen as a marker of conjunctival differentiation.
Identification of factors regulating differentiation and growth of limbal stem cells for corneal surface regeneration
Authors: HOLAN V , TROSAN P , KRULOVA M , ZAJICOVA A
Published: August 2012

Purpose To identify factors which are produced by damaged corneal epithelium and which control proliferation and differentiation of limbal stem cells (LSC).

Methods The central cornea in the mouse was mechanically damaged and the cornea or limbal tissue was excised at different time intervals after injury. The expression of genes for a number of growth and differentiation factors in the cornea or limbus was determined by real‐time PCR. The effects of these factors on the growth and differentiation of LSC in vitro was tested.

Results It was found that the expression of a number of genes in the central cornea was significantly enhanced already 3 or 6 hours after the cornea damage. Insulin‐like growth factor I (IGF‐I) which is strongly upregulated shortly after injury, was identified as the main factor responsible for LSC differentiation into cells expressing cytokeratin K12, a marker of corneal epithelial cells. Furthermore, IGF‐I enhanced expression of its own receptors in LSC, but it had no effect on LSC proliferation. Another two factors produced by the corneal epithelium, fibrocyte growth factor (FGF) and epidermal growth factor (EGF), supported LSC proliferation without effect on their differentiation.

Conclusion IGF‐I was identified as the main factor inducing differentiation of LSC into cells expressing corneal epithelial cell markers. The proliferation of these cells was supported by FGF and EGF.
Gene transfer of HSV1‐specific meganuclease to the murine cornea
Authors: ROUSSEAU A , ERGANI A , GABISON E , CORRAL M , GAILLEDRAT M , DESSEAUX C , ROY P , CHAPELLIER B , LABETOULLE M
Published: August 2012

Purpose Recombinant Adeno‐Associated virus (rAVV) encoding meganucleases specifically designed to address Herpes simplex virus type 1 (HSV1) reduce HSV1 replication both in vitro and ex‐vivo. The main issue of this potential antiviral treatment is the delivery system. To evaluate a vector‐free method, we tested an electroporation process to transfer HSV1‐specific meganucleases (HSV1‐SM) to the murine cornea

Methods Corneal gene transfer was achieved by subconjunctival injection (SCI) of recombinant plasmid encoding either GFP (group 1; n=30) or HSV1‐SM (group 2; n=12), followed by electroporation. Mice were sacrified at day (D)1, 3, 7, 13, 35 (group 1) and at D13 and 35 (group 2). Control group consisted in SCI w/o electroporation. Corneal samples were analyzed for the expression of transcripts encoding GFP and HSV1‐SM using real time PCR. The results were compared to those obtained following SCI of rAAV encoding either GFP or HSV1‐SM

Results For HSV1‐SM, SCI plus electroporation induced a stronger expression than SCI alone at D13. In group 1, the expression of GFP transcripts decreased from D1 to D35. However, until D13, their levels of expression were higher than those obtained with the rAAV method (p<0.002). Similarly, the expression of HSV1‐SM transcripts at D13 was higher than those obtained with the rAAV method (p<0.002), suggesting that therapeutic concentration could be optimised with this method. At D35, results were not statistically different between the 2 methods

Conclusion In our hands, with the method we used, we can conclude that SCI of plasmid encoding HSV1‐SM with immediate electroporation is an efficient method to improve delivery in short‐term but not in long‐term when compared to rAAV
Risk factors for contact lenses related microbial keratitis: a prospective multicenter case control study
Authors: BOURCIER T , SAUER A
Published: August 2012

Purpose MMK remains a rare complication of CL wear, but is of interest because it is both a major cause of new cases of MK in the population, and the only sight‐threatening complication of an otherwise safe method of vision correction. The aim of the study is to identify risk factors and to put into perspective the individual risk and the societal burden of CL‐related MK patients.

Methods A prospective multicenter case‐control study was conducted in 16 French University Hospitals on all lenses wearers presenting with MK between July 2007 and December 2011. Patients had a complete ophthalmological examination and were interviewed by a 50 items anonymous "questionnaire" to determine subject demographics and lenses wear history. The CL related MK subpopulation (Case) was compared to healthy CL wearers (Control).

Results 684 CL related MK and 599 healthy CL wearers were included. Patients wearing soft contact lenses had a higher risk for MK, as compared as rigid lenses wearers (Relative risk, 4.1 ; p < 0.001). Among soft lenses, daily disposable CL (RR, 1.8 ; p = 0.01) and 2 weekly replacement CL (RR, 2.1 ; p < 0.001) had an increased risk of MK than monthly replacement CL, respectively because of some lacks in basic rules of hygiene (absence of hand washing) and the absence of a professional supervision for daily disposable CL and the overtaking of the deadline of renewal for 2 weekly replacement CL.

Conclusion With the increasing avaibility of CL, notably through internet or local market, this study serves to highlight the increasingly documented dangers of freely available CL without professional supervision and of the lack of information about the basic rules of hygiene and the basis of CL care and handling.
Role of human corneal stroma‐derived mesenchymal‐like stem cells in immunity and wound healing
Authors: VEREB Z , ALBERT R , MOE MC , RAJNAVOLGYI E , FESUS L , BERTA A , PETROVSKI G
Published: August 2012

Purpose Mesenchymal stem cells (MSC) are the stromal cells of bone marrow, but they can be also found in other tissues including the cornea. Our goal was to isolate and cultivate human corneal stroma MSC‐like cells (CSMSCs) and study their role in immunity and wound healing.

Methods Corneal buttons were harvested from cadavers (according to the Guidelines of the Helsinki Declaration). The isolated stromal cells were cultured ex vivo in human serum containing medium. Fluorescent microscopy, FACS and gene array analysis, as well as standardized in vitro differentiation assays were performed to investigate the stemness and phenotype of the CSMSCs. To investigate the immunosuppressive function of these cells, mitogen activated lymphocyte reaction and activation by pro‐inflammatory cytokines were used.

Results According to the definition of the ISCT, the most important MSC markers (CD73, CD90 and CD105) were highly expressed on the surface of the CSMSCs with the absence of endothelial or hematopoietic cell markers. The CSMSCs were able to differentiate into fat, bone, cartilage tissues and close wounds within 24 hrs in vitro. They could suppress the proliferation of activated peripheral blood lymphocytes and secrete suppressive cytokines upon pro‐inflammatory activation.

Conclusion We demonstrate a method for isolating and cultivating MSC‐like cells from human corneal stroma. The ex vivo data suggest that these cells may have a role in wound healing and immunological processes in the eye that can possibly be used in future treatments of ocular diseases and corneal stroma injuries.
Tear film proteins attached to soft contact lenses
Authors: NIELSEN K , VORUM H , EHLERS N , HJORTDAL J , HONORé B
Published: August 2012

Purpose Contact lenses (CLs) float on the tear film that is the outer 7‐8 µm liquid layer on the cornea. Proteins can adhere to the surface of CLs. Adhered proteins are the agent for irritation and in case of long wear time and poor hygiene, possibly also for keratitis; as the proteins may serve as an anchor for bacteria to attach to. We have isolated and identified such adhered proteins from the CL surface.

Methods Soft CLs from 3 non‐atopic human individuals were collected. 1‐day, 14‐days and 30‐days lenses were examined. Adhered proteins were removed in denaturing lysis buffer and separated on two‐dimensional polyacrylamide gels that were silver stained. Spots of interest were excised and subjected to in‐gel tryptic digestion prior to liquid chromatography ‐ tandem mass spectrometry analysis.

Results Equal amounts of proteins (20‐40 µg) were separated on 2D‐gels. Protein patterns appeared more intense but with similar patterns with longer wear‐period. A fraction of the observed silver stained protein spots were successfully identified with tandem mass spectrometry. Identified proteins included: lactoferrin, lysozyme C, lipocalin‐1, mammaglobulin, beta‐2‐microglobulin, prolactin‐inducible protein, immunoglobulins, polymeric immunoglobulin receptor, zinc‐alpha‐2‐glycoprotein, cystatin‐S, cystatin‐SN, secretoglobulin family 1D member 1 and serum albumin.

Conclusion Adhered proteins from CLs were isolated and identified. The protein composition resembles the protein composition in tears. The combined techniques of 2D‐gel electrophoresis and mass spectrometry is proven to be a suitable tool to examine proteins adhered to CLs. Proteins from a single set of CLs can be analyzed.
Whole exome sequencing identifies a mutation for a novel form of hereditary benign intraepithelial dyskeratosis
Authors: SOLER V , TRAN‐VIET KN , ST.GERMAIN E , FOURNIE P , KLEMM T , HAWTHORNE F , AFSHARI NA , CALVAS P , MALECAZE F , YOUNG T
Published: August 2012

Purpose To identify a gene for a novel, autosomal dominant form of hereditary benign intraepithelial dyskeratosis (HBID) in a Caucasian French pedigree using deep sequencing technology.

Methods A 7‐member family with two affected individuals (6‐year‐old proband and his mother) with corneal lesions was ascertained. The proband presented with bilateral complete corneal opacification with dyskeratosis, and circumferential corneolimbal neovascularization. Cutaneous features of palmoplantar hyperkeratosis as well as laryngeal dyskeratosis were associated with the ocular phenotype. Histopathology studies of cornea and vocal chord biopsies showed dyskeratotic keratinization. Next generation sequencing with mean coverage of 50x using the Illumina Hi Seq and whole exome capture processing was performed. Sequence reads were aligned, and screened for single nucleotide variant and insertion/deletion calls. In‐house pipeline filtering analyses and comparisons with public databases were performed. cDNA expression studies were conducted using systemic and ocular tissues.

Results A novel missense mutation M77T was discovered for the gene NLRP1 which maps to chromosome 17p13.2. This mutation was de novo in the proband’s mother, followed segregation in the family, and was not found in 800 control DNA samples. NLRP1 expression was determined in adult cornea.

Conclusion A de novo mutation in NLRP1 segregated with HBID in a non‐Native American family. The gene product is implicated in inflammation, autoimmune disorders, and caspase‐mediated apoptosis. This is the first identification of a causative gene for a form of autosomal dominant HBID.
Ocular granulomatosis associated with brimonidine treatment. Does brimonidine have an effect on human macrophages and dendritic cells in vitro?
Authors: BOUABANE I , MAURAGE CA , LABALETTE M , ROULAND JF , LABALETTE P
Published: August 2012

Purpose Conjunctival and episcleral granulomas with uveitis have been reported as a side effect of antiglaucomatous topical use of brimonidine tartrate. We postulated that brimonidine is implicated in this inflammatory process and studied its effects on the antigen presenting cells (APCs) cytokines production.

Methods Conjunctival and episcleral granulomatous lesions were immunohistochemically analyzed for CD3, CD4, CD8, CD1a, CD11c, CD68, and CD123. Macrophages and dendritic cells (DCs) were generated from peripheral blood monocytes of healthy donors and of patients who presented uveitis and granulomatous ocular infiltration induced by brimonidine topical treatment. APCs were respectively exposed to preserved and unpreserved brimonidine tartrate suspension(0.012%),0.005% benzalkonium chloride (BAK) and lipopolysaccharides (LPS). APCs Th1/Th2 cytokines production was measured in supernatants by multiplex flow cytometry.

Results The granulomas consisted predominantly of CD4+ T‐cells and APCs, i.e. epithelioid macrophages CD 68+ and myeloid DCs CD11c+. Comparative exposure of APCs to unpreserved or preserved brimonidine tartrate formulations, or BAK alone, induced similar amounts of pro (IL‐6 or TNF‐α) and anti (IL‐10) inflammatory cytokines. Brimonidine tartrate and BAK reduced the LPS‐stimulated production of IL‐6, TNF‐α and IL‐10.

Conclusion The histhopathological analysis of the conjunctiva and the episclera identified the main cellular actors involved in the granulomatous inflammatory process. By altering the APCs IL‐10 production, brimonidine tartrate will affect induction of tolerance by DCs and allow initiation of immune response leading to granulomas formation.
Ex vivo test bench for preclinical assessment of intra corneal new medical devices is needed more than ever
Authors: BERNARD A , CAMPOLMI N , NEFZAOUI C , THURET G , GAIN P
Published: August 2012

Purpose Intra corneal medical devices (ICMD) currently invade the refractive surgery market, particularly for presbyopia. Proposed to correct a simple loss of accommodation and not a disease, they should have very long‐term efficacy and safety objectives. It becomes evident that pre‐clinical tests must be highly efficient in determining the balance of benefits and risks. Despite the European directive 93/42/EEC that defines this balance, several CE marked ICMD, with a quasi‐cosmetic action, are implanted in healthy human corneas after, at best, non‐representative animal experiments. Aim: to demonstrate the urgent need to develop efficient suitable preclinical assessment methods of these ICMD

Methods Exhaustive review of the literature about animal models and human experimentations used until now for ICMD assessment

Results None of the usual animal models of ICMD assessment seemed acceptable for various reasons: primate for ethical reasons (presbyopia is not a disease), rat, rabbits and cats for biological reasons especially because of their spontaneous endothelial regeneration, or financial reason especially for long‐term monitoring after implantation in primate, pig, calf or ovines. One ICMD (CE marked since 2005) was tested in 24 rabbits, without any endothelial viability testing, before being implanted in human corneas. Several ICMD (one CE marked since 2009) were never submitted to pre‐clinical assessment and were directly implanted in human cornea

Conclusion New pre‐clinical assessment, for example ex vivo test bench with very long term stored and monitored human corneas need to be rapidly developed and validated in order to improve patient safety
Impact of photodynamic inactivation (PDI) on bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes in vitro
Authors: SZENTMARY N , STACHON T , WANG J , EPPIG T , LANGENBUCHER A , BISCHOFF M , FOTH HJ , SEITZ B
Published: August 2012

Purpose Photodynamic inactivation (PDI) may eliminate the microorganisms from the infected cornea by damages caused through free oxygen radicals, or even by supporting different stages of activation of keratocytes and inflammatory cell response. The purpose of this study was to determine the impact of PDI on bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes in vitro.

Methods Primary human keratocytes were isolated by digestion in collagenase A (1 mg/ml) from human corneal buttons, and cultured in DMEM/Ham’s culture medium supplemented with 10% FCS. Keratocytes underwent illumination (670 nm) for 13 minutes following exposure to 100 nM concentration of photosensitizer chlorin e6 (Ce6) in the culture medium. One day after treatment, bFGF, HGF, KGF, TGFß1 and VEGF release of the cells was determined using enzyme‐linked immunosorbent assay (ELISA).

Results One day after PDI, the secretion of bFGF was 1.58, of HGF 1.61, of KGF 0, of TGFß1 2.83 and of VEGF 9.01 pg/µg protein. The secretion of bFGF decreased (p=0.007) significantly one day after PDI, compared to controls. In HGF, KGF, TGFß1 and VEGF secretion no significant changes could be detected. Using Ce6 or illumination only, bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes did not change significantly.

Conclusion As a short‐term effect, PDI decreases bFGF release of keratocytes in vitro. The altered secretion of these factors may play a role in the activation of keratocytes following PDI.
Expression of stromelysins 2 and 3 in rabbit corneal epithelium upon UV radiation
Authors: ARDAN T
Published: August 2012

Purpose Stromelysins belong to the group of matrix metalloproteinases (MMPs). These enzymes degrade many extracellular matrix proteins in the basement membrane, including proteoglycans and laminin, but are unable to cleave the fibrillar collagens. Activated stromelysin, via its capacity to catabolize proteoglycans, is likely to help reestablish transparency by returning the proteoglycan ratio to normal during remodeling. Purpose of this study was to investigate the effect of UVA and UVB rays on the expression of stromelysin 2 (MMP‐10) and 3 (MMP‐11) in the corneal epithelium.

Methods In the first group of rabbits the corneas were irradiated with UVA lamp (365 nm, once a day during 4 days, and a dose per day 1.01 J/cm2). In the second group of rabbits the corneas were irradiated with UVB lamp (312 nm, once a day during 4 days, and a dose per day 1.01 J/cm2). Stromelysin 2 and 3 were examined on cryostat sections immunohistochemically by using sheep polyclonal anti‐MMP‐10 and anti‐MMP‐11 antibodies.

Results Our immunohistochemical results showed that UVA rays did not change the expression of both stromelysins studied in the corneal epithelium. In contrast, UVB rays induced the increased expression of stromelysin 2 and 3 in corneal epithelial cells.

Conclusion Even if further studies are necessary, our results point to the suggestions that increased stromelysins after UVB irradiation can participate in remodeling processes during corneal wound healing.
Gelatinous drop like dystrophy (GDLD) in a Sudanese patient
Authors: AKHTAR S , GUGGENHEIM J , ALKATAN H , KIRAT O , ALMUBRAD T
Published: August 2012

Purpose Gelatinous drop‐like corneal dystrophy (GDLD) (OMIM #204870) is an early‐ onset, autosomal recessive corneal dystrophy, reported globally. It presents in the ﬁrst decade of life with bilateral, mulberry‐like or gelatinous lesions, due to amyloid deposition in the superﬁcial cornea.

Methods A 50 year old Sudanese patient was diagnosed for GDLD. The patient had penetrating keratoplasty in the right eye. The tissue was processed for light and electron microscopy. A DNA sample was screened for 333 sequence variants in 13 corneal dystrophy genes by Asper Ophthalmics Ltd, followed by confirmatory sequencing.

Results The GDLD cornea contained deposits of amyloid fibrils at the sub‐epithelial region and in various parts of stroma. The deposits were Congo red positive and showed apple green birefringence under polarized light. The growth of amyloid fibrils was associated with large splits between lamellae, a reduced diameter of collagen fibrils and degeneration of keratocytes. A homozygous c.355T>A mutation in exon 1 of the TACSTD2 (M1S1) gene was identified, not present in dbSNP, predicted to cause a pathogenic amino acid change (p.Cysl19Ser in NCBI entry NP_002344.2).

Conclusion The cornea of this GDLD patient with a novel c.355T>A mutation in exon 1 of TACSTD2 showed degeneration of the corneal epithelium, Bowman’s layer, stroma and keratocytes. Deposits of amyloid were found in the sub‐epithelium region, Bowman’s layer, and stroma. Acknowledgement: Supported by National Plan for Science and Technology, KSU, Riyadh.
The correlation between central corneal thickness and endothelial cells in healthy patients and in patients with cataract or primary open angle glaucoma
Authors: JURKUTE N , PAJAUJIS M , GALGAUSKAS S , KRASAUSKAITE D , ASOKLIS R
Published: August 2012

Purpose To compare the endothelial cells parameters and central corneal thickness (CCT) in four different groups of patients, to find the correlation between the corneal endothelial cell density (ECD) and the cell size, percentage of regular hexagonal cells, CCT and age in all four groups.

Methods All patients (104 eyes) were devided into 4 groups: patients with cataract, with primary open angle glaucoma (POAG), young healthy people and older healthy people. Specular microscopy was performed, endothelial cells parameters were analyzed (ECD, the percentage of regular hexagonal cells), CCT was measured.

Results There were 47 (45%) male, 57 (55%) female. Average age was 59 (± 23.8) years. In the POAG group average CCT was 553 (± 32) µm, ECD 2484 (± 482) cell/mm2, hexagonal cells 60% (± 10%). In the cataract group CCT was 540 (± 64) µm, ECD was 2633 (± 430) cell/mm2, hexagonal cells 60% (± 10%). In young healthy subjects average CCT was 555 (± 43) µm, ECD 2940 (± 345) cell/mm2, hexagonal cells 66% (± 10%), in the older healthy patients group average CCT was 545 (± 39) µm, ECD 2394 (± 416) cell/mm2, hexagonal cells 64% (± 10%).

Conclusion The ECD is higher in thicker corneas. In young subjects ECD was higher than in elderly patients. In males the percentage of regular hexagonal cells was higher than in females. There was no statistically significant difference in CCT and ECD between the gender. We have found very weak statistically significant direct relationship between ECD and CCT. There was no statistically significant difference in CCT and percentage of hexagonal cells in corneal endothelium in all groups.
Three year visual outcomes and correlation with graft thickness in eyes following descemet stripping automated endothelial keratoplasty (dsaek)
Authors: LIM FPM , ANG M , HTOON H , TAN D , MEHTA J
Published: August 2012

Purpose To describe 3 year visual outcomes and correlation with graft thickness in eyes following Descemet Stripping Automated Endothelial Keratoplasty (DSAEK).

Methods Retrospective case series of 106 consecutive eyes that underwent DSAEK. We recorded clinical characteristics , best‐corrected visual acuity (BCVA) and serial measurements of central graft thickness and total central corneal thickness using anterior segment optical coherence tomography over a 3‐year follow‐up. Correlation analysis of preoperative and postoperative graft thickness with BCVA at 1, 2 and 3 years were performed.

Results Mean age of recipients was 64.5 years (± 11.8) years. The median preoperative logarithm of the minimal angle of resolution (logMAR) BCVA was 0.71. There was significant improvement in post‐operative BCVA at 1‐year (median improvement in BCVA 0.41, P<0.001), but no significant improvement in BCVA after 2 year post operatively (P=0.563). Likewise, median central graft thickness significantly decreased post‐operatively over the first year (190um vs 166 um, P<0.001), but no significant reduction of graft thickness after 2 years post‐operatively (P=0.17). There were no correlations between preoperative graft thickness and BCVA logMAR at 1 year (Spearman=‐0.187; p= 0.069), 2 year (Spearman= ‐0.049; p= 0.650) or at 3 year (Spearman=‐0.068; p= 0.614). There were also no significant correlations of logMAR BCVA with post‐operative graft thickness by AS‐OCT at any time point.

Conclusion Visual acuity significantly improves after DSAEK over the first year postoperatively. However, no correlation can be found between both preoperative and postoperative graft thickness and BCVA over 3 year follow up.
Distribution of the central corneal thickness in adult residents of Lithuania
Authors: GALGAUSKAS S , LIUTVINAITE R , JUODKAITE G , TUTKUVIENE J , ASOKLIS R
Published: August 2012

Purpose To determine the distribution of the central corneal thickness by age and gender in Lithuanian population.

Methods Lithuanian residents in the age of 18 and senior, who were registered with the primary health care institutions (PHCI) of different Lithuanian cities and regions participated in the survey. Data including age, gender and measurement of central corneal thickness (CCT) of all tested persons was registered. CCT of each eye was measured by using the ultrasound contact pachymeter. The results were statistically analysed by SPSS 17,0 program.

Results In total 1650 residents of Lithuania were tested, including 688 (41, 7%) men and 962 (58.3%) women. The average age among men was 57.31 ± 0.61, and among women ‐ 53, 63 ±0.74. The average CCT of individuals by age groups equalled to: 18‐29 (550,8 ±2,8 µm), 30‐39 (557,5±1,9 µm), 40‐49 (551,3±1,8 µm), 50‐59 (544,0±1,9 µm), 60‐69 (544,2±2,1 µm), 70‐79 (535,1±1,9 µm), and 80+ (530,1±1,1 µm)( p=0,000, p<0,05). The central corneal thickness of the tested men and women by different age groups (under 40, from 40 to 60 years of age, and over 60) was calculated in percentiles. Corneas of persons under 40 are thicker than of persons in the age between 40 and 60, and corneas of the tested senior persons over 60 are thinner in comparison with other age groups.

Conclusion The average CCT among Lithuanian residents in general is 544,6± 0,7 m, 545,0±0,8 m of men, and 544,4±1,1 m of women. The thickest cornea among Lithuanian residents was measured in individuals under 40. In senior persons it becomes thinner by each decade from 2 to 8µm. The central corneal thickness has no relevance to gender.
Efficacy of amniotic membrane transplantation (AMT) on corneal surface in bullous keratopathy eyes
Authors: KOEV K
Published: August 2012

Purpose To determine the effect of cryopreserved amniotic membrane transplantation (AMT) on a patients with bullous keratopathy in pseudophakia eyes.

Methods This retrospective study included 5 eyes (5 patients) with bullous keratopathy in pseudophakia eyes presenting with intractable pain or discomfort (photophobia, tearing and foreign‐body sensation). A transplantation of sutureless temporary cryopreserved amniotic membrane was performed on all eyes suffering from bullous keratopathy. The average duration of the follow‐up was 14.1 months +/‐ 1.6 (SD) (range 12 to 16 months).

Results After the AMT was established a significant improvement. We observed complete corneal epithelial healing in all eyes. Sixty percent of the 5 eyes had improvement of the ocular discomfort soon after the first postoperative day. Pain relief was obtained in 80% of patients.

Conclusion The AMT was efficient, safe, and successful method of treatment for intractable pain with chronic bullous keratopathy. Future studies comparing AMT to other methods of treatment of bullous keratopathy would help to better define the role of AMT in ocular surface disease and perhaps further elucidate the mechanisms by which this therapy works. Keywords: Amniotic membrane transplantation, pseudophakia, bullous keratopathy, intractable pain, discomfort
Keratoconus screening based on data of the high resolution anterior segment OCT Casia 1000
Authors: LANGENBUCHER A , GILLNER M , KANNENGIESSER M , EPPIG T
Published: August 2012

Purpose Anterior segment OCTs are more and more used in clinical practice for evaluation of corneal disorders. The goal of the study was to derive an automatic screening method for diagnosis of forme fruste and early keratoconus based on data extracted from the OCT CASIA‐1000 (Tomey Inc., Japan).

Methods From the Casia‐1000 we exported the following raw data: anterior and posterior surface dioptric power data, anterior and posterior surface elevation data, pachymetric data (central, thinnest + X‐Y‐position). These data were decomposed into Zernike base of radial degree 6 and single indices and combinations (compound index 1 and 2) were tested for specificity and sensitivity (ROC analysis, area under curve). Ninety eyes of 45 patients were included in this study (1 eye each with clinical manifest signs of keratoconus the other without clinical signs of keratoconus each) and 48 eyes of 48 normals as reference.

Results For the single indices the tilt and coma component of 1st and 2nd radial degree showed the best discriminance level between normal and suspects/keratoconus (area up to 0.74/0.86). Compound index 1 considering anterior and posterior surface coma of 1st and 2nd radial degree and pachymetry yielded a discriminance level of 0.821/0.953 and compound index 2 without considering pachymetry showed 0.799/0.935, respectively.

Conclusion The single indexes do not seem do provide better discrimination between normals and suspects/keratoconus compared to the literature data for corneal topography (e.g. Klyce, Maeda, Smolek) or Tomography (Belin&Ambrósio). But in contrast, especially compound index 1 shows an excellent performance. These results have to be validated in a larger case series comparing Casia‐1000, TMS and Pentacam.
Boston Keratoprosthesis (Type I): visual prognosis and complications
Authors: DE LA PAZ M , STOIBER J , MICHAEL R
Published: August 2012

Purpose to describe the functional results and sight threatening post‐operative complications of Type I Boston Keratoprosthesis.

Methods retrospective descriptive study of Boston Keratoprosthesis patients from two European eye centers.

Results A total of 66 eyes were included for analysis. Mean follow‐up time was 28 months. Majority of patients had more than 2 penetrating keratoplasties, primary clinical diagnosis are presented. Mean preoperative best corrected visual acuity was 2.05, mean best ever achieved post‐operative best corrected visual acuity was 1.16 and final mean postoperative best corrected visual acuity was 1.47 . The most common sight‐threatening complications were as follows: retroprosthetic membrane, retinal/choroidal detachment, infectious keratitis, endophthalmitis, peripheral retinal occlusive vasculitis and prosthesis extrusion. Management of complications are discussed.

Conclusion 95 % retention rate with overall improvement in visual acuity demonstrates that Type I Boston Keratoprosthesis is a good alternative to cases of multiple graft failure due to various primary clinical diagnoses. Complications must be detected early on and managed accordingly to ensure success of the procedure.
Ukraine implantation results of collagen‐based bioengineered substitutes of donor corneal allografts in rabbits
Authors: BOYCHUK IRYNA , PASECHNIKOVA NV , LEUS M , BUZNYK OI , GRIFFITH M
Published: August 2012

Purpose Ukraine Implantation Results of Collagen‐Based Bioengineered Substitutes of Donor Corneal Allografts in Rabbits

Methods Bioengineered corneal substitutes (BCS) were fabricated by cross‐linking porcine type I collagen with carbodiimide and N‐hydroxysuccinimide as described by Liu et al., 2006. BCS refractive indices were measured using an Abbe refractometer. The mechanical properties were evaluated by their ability to tolerate interrupted sutures placed during deep lamellar keratoplasty performed on isolated rabbit eye. BCS were then implanted into one cornea each of 8 rabbits and followed‐up for 12 months.

Results Our BCS had refractive indices of 1.24‐1.3 (human cornea 1.37‐1.38). They tolerated placement of 12 interrupted sutures well. New technique of BCS “sutureless” implantation was elaborated. When implanted into rabbit corneas, the BCS remained stably integrated and optically clear during 12 month follow‐up. Grade 1.5 haze (scale 0‐4) was observed in 2/8 eyes during the 1st postoperative week. In one eye, the haze resolved. In the 2nd eye, the grade 1 haze remained. Light microscopy confirmed good integrity of the BCS and absence of inflammation.

Conclusion Our current data suggest that the BCS fabricated in Ukraine by cross‐linking collagen is a good alternative to human donor corneas, if medical grade porcine collagen is used. The new “sutureless” implantation technique may decrease BCS damage and accelerate its epithelialisation
Influence of intraocular pressure on the photorefractive keratectomy for myopia correction. a numerical analysis
Authors: DEL BUEY MA , LANCHARES E , CALVO B , LAVILLA L , CRISTOBAL JA , CASAS P , ASCASO F , CRUZ N , JIMENEZ B , DOBLARE M , PALOMINO C
Published: August 2012

Purpose To analyze the effect of the intraocular pressure (IOP) on the refractive correction achieved by the Photorefractive Keratectomy (PRK) surgery using a biomechanical model of the human eye.

Methods A three‐dimensional finite element model of the human eye was used to simulate the PRK surgery. A hyperelastic constitutive behavior was assumed for all the tissues of the model. Simulations of PRK surgery for five levels of myopia (2, 4, 6, 8 and 10 diopters) at three physiological healthy values of IOP (10, 15 and 21 mmHg) were performed and the post‐surgical diopters were estimated.

Results For low and medium values of IOP (10 and 15 mmHg), the computed results were close to those used by clinicians and defined without considering the IOP, while undercorrection was predicted for the highest value of IOP (21 mmHg) in the 8 and 10 diopter correction cases.

Conclusion From these results, we suggest that IOP should be considered in the determination of the depth of ablation, in addition to other factors.
Combined treatments for keratoconus: a numerical approach
Authors: DEL BUEY MA , LANCHARES E , CRISTOBAL JA , CALVO B , CASAS P , ASCASO F , CRUZ N , LAVILLA L , JIMENEZ B , PEIRO C , PALOMINO C
Published: August 2012

Purpose To compare the effects of two combined treatments, corneal collagen crosslinking (CXL) and insertion of intrastromal ring segments (ISRS), for the treatment of keratoconus, using a biomechanical model of the keratoconic cornea

Methods Numerical simulations of both treatments are performed using a biomechanical model of a human keratoconic cornea. Then, simulations of the combination of the two treatments are performed: first CXL and afterwards, ISRS insertion; firs ISCRS insertion and afterwards, CXL.

Results After the numerical simulation, the following effects are observed: the CXL causes a stiffening of the corneal tissue; the insertion of ISRS induces a flattening of the central area of the cornea causing a hyperopic effect and a decrease of the anterior chamber depth (ACD), as our clinical outcomes confirm. The insertion of ISRS achieve higher effect when the CXL treatment is previously performed.

Conclusion The combination of the two treatments, collagen CXL and ISRS insertion, achieve a regularization of the shape of the cornea. According to the outcomes of numerical simulation, collagen CXL must be performed before the insertion of the ISRS in order to achieve better results.
Usefulness of the optical coherence tomography Spectralis® anterior segment module in the diagnosis and monitoring of corneal pathology
Authors: JIMENEZ DEL RIO B , DEL BUEY MA , CRISTOBAL JA , CRUZ N , RAMIRO P , MATEO J , CASAS P , PADGETT E
Published: August 2012

Purpose The Spectralis® Anterior Segment Module that offers Spectral‐Domain Optical Coherence Tomography (SD‐OCT) Heidelberg Engineering, is a sign of the revolution who are suffering OCT teams nowadays. The aim of our study is to analyze the usefulness of optical coherence tomography of anterior segment in the diagnosis and monitoring of different corneal diseases.

Methods Some ophthalmologists explored their patients from department of cornea and ocular superfie under slit lamp and later with the OCT Anterior Segment Module. The Spectralis SD‐OCT offers high quality images of cornea and anterior segment, without any contact and comfort for the patient. Because it is installed on a slit lamp is very intuitive and easy to use, so no special training is required.

Results We present several cases where we used optical coherence tomography of anterior segment in the diagnosis of different corneal diseases: degeneration, infections, dystrophies... and also in following various surgical procedures such as intrastromal corneal rings, keratoplasty, lamellar corneal graft and amniotic membrane coatings.

Conclusion We believe it is a useful diagnostic tool in every department of cornea, refractive surgery and ocular surface diseases to document, make measurements and studies of evolution and, especially, to evaluate the surgical results.