Johnny Moore

Excimer laser surface ablation - a review

Corneal surface laser ablation procedures for the correction of refractive error have enjoyed a resurgence of interest, especially in patients with a possible increased risk of complications after lamellar surgery. Improvements in the understanding of corneal biomechanical changes, the modulation of wound healing, laser technology including ablation profiles and different methods for epithelial removal have widened the scope for surface ablation. This article discusses photorefractive keratectomy, trans‐epithelial photorefractive keratectomy, laser‐assisted sub‐epithelial keratomileusis and epithelial‐laser‐assisted in situ keratomileusis.

Sutureless and glue-free conjunctival autograft in pterygium surgery: a case series

AimsForeign materials used in ocular surface surgery may lead to local complications such as discomfort, scarring, or infection. Plasma-derived products such as fibrin glue may produce possible hypersensitivity reactions whereas the risk of viral transmission remains. We describe a simple method of achieving conjunctival autograft adherence during pterygium surgery avoiding potential complications associated with the use of fibrin glue or sutures.MethodsAfter pterygium excision and fashioning of the autologous conjunctival graft, the recipient bed is encouraged to achieve natural haemostasis and relative dessication before graft placement. Excessive haemorrhage in the graft bed is tamponaded. Graft adherence and positioning is examined 20u2009min after surgery.ResultsA total of 15 eyes of 12 patients (mean (SD) age 73.7 (11.2) years), 8 females underwent SGF autologous conjunctival graft post-pterygium excision. Mean graft area was 24(1.5)u2009mm2. Mean follow-up time was 9.2 (2.2) months. Cosmesis was excellent in all cases and visual acuity improved in one patient. There were no intra- or post-operative complications requiring further treatment.ConclusionThis simple technique for pterygium surgery may prevent potential adverse reactions encountered with the use of foreign materials and in this small series provided safe and comparable results to current methods.

A novel mutation in KRT12 associated with Meesmann's epithelial corneal dystrophy

Background: The molecular basis of Meesmanns epithelial corneal dystrophy (MECD) has recently been attributed to mutations in the cornea specific keratin genes KRT3 and KRT12. The mechanisms by which these mutations cause the Meesmanns phenotype are not clear. This study presents new data, examines clinical, histological, ultrastructural, and molecular aspects of MECD, and compares the features seen in this condition with those observed in other well studied keratin diseases such as epidermolysis bullosa simplex. Methods: A two generation family with typical features of Meesmanns epithelial corneal dystrophy (MECD) was studied. All family members were examined under a slit lamp. Biopsy material from elective keratoplasty was studied by histopathological and ultrastructural analysis using standard techniques. Direct automated sequencing of genomic DNA was used for mutation detection, mutations were confirmed by restriction digest analysis. Results: The abnormal corneal epithelium was acanthotic and contained numerous dyskeratotic cells and intraepithelial vesicles. By electron microscopy abnormally aggregated and clumped keratin filament bundles were detected in basal and suprabasal keratinocytes from the centre of the cornea. Direct sequencing of the patients genomic DNA revealed a novel missense mutation (423T>G) in exon 1 of the cornea specific keratin 12 (KRT12) gene. This mutation predicts the amino acid change N133K within the helix initiation motif of the K12 polypeptide. Comparative studies with well established keratin disorders of other human epithelia underscore the pathogenic relevance of K3 and K12 gene mutations in Meesmanns epithelial corneal dystrophy. The morphological data presented here illustrate the disruptive effects of keratin gene mutations on the integrity of corneal keratinocytes. Conclusions: A clinical, histopathological, and ultrastructural study of a previously unreported family with MECD is presented. In this family the disease is ascribed to a novel mutation in KRT12. A molecular mechanism is proposed for MECD based on the comparison with other well characterised keratin diseases.

Early Flap Displacement after LASIK

PURPOSEnTo evaluate the risks of flap displacement after LASIK.nnnDESIGNnRetrospective case series.nnnPARTICIPANTSnWe included 41 845 consecutive adults who underwent LASIK surgery at Optical Express in the United Kingdom, including 81 238 eyes, of which 14 555 were hyperopic and 66 681 myopic or mixed astigmatic. We treated 57 241 eyes with the IntraLase FS-60 femtosecond laser and 23 997 with the Moria S.A. ONE Use-Plus automated microkeratome.nnnMETHODSnWe calculated the incidence of all flap displacements in the study population during an observational time period of ≥12 months after surgery. Independent variables were entered into logistic regression models to identify risk factors. Postoperative outcomes were assessed.nnnMAIN OUTCOME MEASURESnThe incidence and odds ratios (OR) of flap displacement in the study population and in categories of refractive error and flap surgery technique.nnnRESULTSnThe incidence of flap displacements was 10 in 81 238 LASIK procedures (0.012%), including 8 hyperopic eyes (0.055%) and 2 myopic eyes (0.003%). All flap displacements occurred within 48 hours of surgery and none were preceded by ocular trauma. They were classified as early flap displacements (EFD). The incidence of EFD after microkeratome surgery was 0.033% (n = 8), and after femtosecond laser it was 0.003% (n = 2). In hyperopic eyes having microkeratome surgery, the incidence was 0.179% (n = 7). In a logistic regression model, the strongest predictor of EFD after LASIK was hyperopia, recording an OR of 19.29 (P<0.001). The OR of developing an EFD after microkeratomy was 10.53 times higher than after femtosecond laser (P<0.005). In hyperopes, the OR of an EFD was 18.87 times higher after microkeratomy than after femtosecond treatment. Four of 10 displaced flaps needed secondary surgery, and 1 eye lost 2 lines of best-corrected visual acuity.nnnCONCLUSIONSnThe incidence of flap displacements during a 12-month period after LASIK was extremely low (0.012%). Although the small number of displacements with the femtosecond laser limits conclusions, the risk of EFD was higher after microkeratome surgery than femtosecond laser.

Development of allele-specific gene-silencing siRNAs for TGFBI Arg124Cys in lattice corneal dystrophy type I.

PURPOSEnThis study aimed to investigate the potency and specificity of short-interfering RNA (siRNA) treatment for TGFBI-Arg124Cys lattice corneal dystrophy type I (LCDI) using exogenous expression constructs in model systems and endogenous gene targeting in an ex vivo model using corneal epithelial cell cultures.nnnMETHODSnA panel of 19 TGFBI-Arg124Cys-specific siRNAs were assessed by a dual-luciferase reporter assay. Further assessment using pyrosequencing and qPCR was used to identify the lead siRNA; suppression of mutant TGFBIp expression was confirmed by Western blot and Congo red aggregation assays. An ex vivo model of LCDI was established using limbal biopsies from corneal dystrophy patients harboring the Arg124Cys mutation. Treatment efficiency of the siRNA was assessed for the inhibition of the mutant allele in the primary patients corneal epithelial cells using pyrosequencing, quantitative PCR (qPCR), and an ELISA.nnnRESULTSnA lead siRNA was identified, and demonstrated to be potent and specific in inhibiting the TGFBI-Arg124Cys mutant allele at the mRNA and protein levels. Besides high allele specificity, siRNA treatment achieved a 44% reduction of the endogenous Arg124Cys allele in an ex vivo model of LCDI.nnnCONCLUSIONSnWe have identified a lead siRNA specific to the TGFBI-Arg124Cys mutant allele associated with LCDI. Silencing of exogenous TGFBI was observed at mRNA and protein levels, and in an ex vivo model of LCDI with an efficient suppression of the endogenous mutant allele. This result indicates the potential of siRNA treatment as a personalized medicine approach for the management of heritable TGFBI-associated corneal dystrophies.

The estimation of approximate sample size requirements necessary for clinical and epidemiological studies in vision sciences

PurposeThe aim of this paper is to provide an overview of sample size estimations for the most frequent type of group studies that result in continuous, binary and ordered categorical outcomes.MethodsThe theory behind power and sample size calculations is explained using the basic probability concepts that underpin the most frequently used statistical significance tests.ResultsSimple formulae and tables are presented for the estimation of sample sizes necessary for efficient and effective clinical and epidemiological trials. These may be used without recourse to sophisticated and complex computer software packages. Mathematical complexity is kept to a minimum. Examples and applications from the vision sciences are specifically highlighted.ConclusionsThe paper highlights, with practical examples, the concepts and computations necessary to make sample size estimations accessible to all eye professionals involved in research, diagnostic and statutory work.

Endoscopic visualisation to aid deep anterior lamellar keratoplasty.

AbstractAimsu2003The aim of this study was to assess the value of endoscopy during deep anterior lamellar keratoplasty (DALK) by visualising the posterior cornea. This allows the surgeon to determine whether air injection had succeeded in stripping Descemets membrane and endothelium from the posterior corneal stroma.Methodsu2003Four whole globes for research were obtained from the Florida eye bank with consent. A 2u2009mm incision was placed at the limbus and the endoscope was introduced through this into the anterior chamber. A 26-gauge needle was introduced into the cornea with the bevel positioned as deep as possible and air injected into the corneal stroma. Air was injected until the whole cornea became opaque and repeated air injections were made even after an opaque cornea was noted. The endoscopic camera was used to visualise the posterior corneal surface during this procedure.Resultsu2003The view of the posterior corneal surface was clear and introduction of the probe did not interfere with the air dissection. In all four eyes, despite ease of air injection and diffuse corneal air infiltration, no large air bubble dissection of Descemets membrane from adjacent stroma occurred. Instead multiple blistering of the posterior corneal surface could be seen.Conclusionsu2003Endoscopy provides an effective tool to visualise the posterior corneal surface during DALK, using air dissection. This technique may become a standard adjunctive procedure during DALK.

siRNA Silencing of the Mutant Keratin 12 Allele in Corneal Limbal Epithelial Cells Grown From Patients With Meesmann's Epithelial Corneal Dystrophy

PURPOSEnThe aim of this study is to further assess our previously reported keratin 12 (K12)-Leu132Pro specific siRNA in silencing the mutant allele in Meesmanns Epithelial Corneal Dystrophy (MECD) in experimental systems more akin to the in vivo situation through simultaneous expression of both wild-type and mutant alleles.nnnMETHODSnUsing KRT12 exogenous expression constructs transfected into cells, mutant allele specific knockdown was quantified using pyrosequencing and infrared Western blot analysis, while the silencing mechanism was assessed by a modified rapid amplification of cDNA ends (5RACE) method. Corneal limbal biopsies taken from patients suffering from MECD were used to establish cultures of MECD corneal limbal epithelial stem cells and the ability of the siRNA to silence the endogenous mutant KRT12 allele was assessed by a combination of pyrosequencing, qPCR, ELISA, and quantitative-fluorescent immunohistochemistry (Q-FIHC).nnnRESULTSnThe siRNA displayed a potent and specific knockdown of K12-Leu132Pro at both the mRNA and protein levels with exogenous expression constructs. Analysis by the 5RACE method confirmed siRNA-mediated cleavage. In the MECD cells, an allele-specific knockdown of 63% of the endogenous mutant allele was observed without effect on wild-type allele expression.nnnCONCLUSIONSnCombined with an effective delivery vehicle this siRNA approach represents a viable treatment option for prevention of the MECD pathology observed in K12-Leu132Pro heterozygous individuals.

Protein Composition of TGFBI-R124C- and TGFBI-R555W- Associated Aggregates Suggests Multiple Mechanisms Leading to Lattice and Granular Corneal Dystrophy.

PURPOSEnTransforming growth factor beta-induced (TGFBI)-related dystrophies constitute the most common heritable forms of corneal dystrophy worldwide. However, other than the underlying genotypes of these conditions, a limited knowledge exists of the exact pathomechanisms of these disorders. This study expands on our previous research investigating dystrophic stromal aggregates, with the aim of better elucidating the pathomechanism of two conditions arising from the most common TGFBI mutations: granular corneal dystrophy type 1 (GCD1; R555W) and lattice corneal dystrophy type 1 (LCD1; R124C).nnnMETHODSnPatient corneas with GCD1 and LCD1 were stained with hematoxylin and eosin and Congo red to visualize stromal nonamyloid and amyloid deposits, respectively. Laser capture microdissection was used to isolate aggregates and extracted protein was analyzed by mass spectrometry. Proteins were identified and their approximate abundances were determined. Spectra of TGFBIp peptides were also recorded and quantified.nnnRESULTSnIn total, three proteins were found within GCD1 aggregates that were absent in the healthy control corneal tissue. In comparison, an additional 18 and 24 proteins within stromal LCD1 and Bowmans LCD1 deposits, respectively, were identified. Variances surrounding the endogenous cleavage sites of TGFBIp were also noted. An increase in the number of residues experiencing cleavage was observed in both GCD1 aggregates and LCD1 deposits.nnnCONCLUSIONSnThe study reveals previously unknown differences between the protein composition of GCD1 and LCD1 aggregates, and confirms the presence of the HtrA1 protease in LCD1-amyloid aggregates. In addition, we find mutation-specific differences in the processing of mutant TGFBIp species, which may contribute to the variable phenotypes noted in TGFBI-related dystrophies.

Fingerprick autologous blood: a novel treatment for dry eye syndrome

PurposeDry eye syndrome (DES) causes significant morbidity. Trials of blood-derived products in treatment of the condition show promising results. However, their production is expensive and time-consuming. We investigate fingerprick autologous blood (FAB) as an alternative low-cost, readily accessible treatment for DES.Patients and methodsProspective, non-comparative, interventional case series. In total, 29 eyes of 16 DES patients (2 males and 14 females) from two NHS sites in the United Kingdom. Patients instructed to clean a finger, prick with a blood lancet, and apply a drop of blood to the lower fornix of the affected eye(s), 4 times daily for 8 weeks then stop and review 4 weeks later. Follow-up visits occurred ~3 days, 2, 4, 8 weeks into therapy, and 4 weeks post-cessation. At each visit, visual acuity, corneal staining, Schirmer’s test, tear break-up time (TBUT), and ocular comfort index (OCI) were measured, and photographs taken. Results were analysed using Student’s paired t-test.ResultsAt 8 weeks, there was improvement in mean Oxford corneal staining grade (3.31 to 2.07 (P<0.0001)), TBUT (5.00 to 7.80u2009s (P<0.05)), visual acuity (0.08 to 0.01 LogMAR equivalent (P<0.05)), and OCI score (56.03 to 39.72 (P<0.0001)). There was no statistically significant change in Schirmer’s test results. Four weeks post-cessation versus immediately after completion of FAB therapy, mean staining grade worsened from 2.07 to 2.86 (P<0.0001). OCI score worsened from 39.72 to 44.67 (P<0.05).ConclusionsIn our limited case series FAB appears to be a safe and effective treatment for DES.