Novel application of Deep Anterior Lamellar Keratoplasty for retinal detachment repair in totally opaque cornea secondary to aniridia

PURPOSE

We present a novel approach for managing retinal detachment in a patient with aniridia related corneal scarring precluding fundal view via a deep anterior lamellar keratoplasty.

METHODS

A 30-year-old female patient who had bilaterally opaque cornea, due to advanced aniridia related keratopathy presented with, experiencing flashing of light in her right eye. Examination of the retinal fundus was not possible due to the dense corneal scarring and underlying cataract. A superior bullous macula off retinal detachment was diagnosed on ultrasonography. Visual acuity at presentation was hand motions. The corneal scarring extended to the mid to deep stroma. We performed a deep anterior lamellar dissection of the opacified corneal stroma, that allowed clear visualisation of a dense cataract. The cataract was removed by phacoemulsification and IOL inserted. This allowed to proceed with repair of retinal detachment, through pars plana approach. The surgery was completed by a donor deep lamellar keratoplasty.

RESULTS

This achieved a good fundal view to proceed with phacovitrectomy visualised through the residual corneal layers. Uneventful pars plana vitrectomy, cryotherapy and SF6 gas were performed to reattach the retina. Post-operatively the graft remains clear at 6 months with a visual acuity of 20/160 in the right eye, a level of vision the patient had not experienced for decades.

CONCLUSION

Deep anterior lamellar keratoplasty offered an alternative to temporary keratoprosthesis to achieve a clear view of the retinal fundus and perform pars plana vitrectomy and repair of the retinal detachment.

Potential cost of assumptions within a visual assessment

We report a man in his 80s who described sudden unilateral loss of vision, resulting in extensive urgent investigations by the accident and emergency department team. Subsequent evaluation of visual acuity with pinhole demonstrated significant improvement, triggering further questioning. It transpired that he was mistakenly wearing his wife's glasses, which accounted for his visual symptoms. This case illustrates the importance of a stepwise approach to visual assessment, and avoiding assumptions, as using the simple pinhole test could have avoided extensive investigations and their subsequent costs.

Case for conservative management of adenoviral pseudomembranous conjunctivitis

The clinical course of adenoviral pseudomembranous conjunctivitis is mostly self-limiting and requires only supportive management measures; however, a minority of patients may develop severe inflammation in response to the virus, which can present as subepithelial infiltrates and pseudomembranes. In its most severe form, symblepharon can result from the inflammatory response resulting in longer-term clinical sequelae. The optimal management of adenoviral pseudomembranous conjunctivitis is poorly defined and while debridement is commonly recommended, there is limited evidence base to support this practice. In this paper, we present two cases of PCR-proven adenoviral pseudomembranous conjunctivitis managed conservatively with topical lubricants and corticosteroids rather than debridement to good effect.

Estimations of Critical Clear Corneal Incisions Required for Lens Insertion in Cataract Surgery: A Mathematical Aspect

In a routine cataract operation cornea tissue may be damaged when an intra-ocular lens (IOL) injector of diameter between 1.467 and 2.011 mm is inserted through an empirically designed 2.2 mm corneal incision. We aimed to model and estimate the minimal length of the incision required to avoid wound tear. It was assumed that the damage was caused by tissue fracture at the tips of the incision, and this fracture could be studied using damage and fracture mechanics. The criterion of the damage was caused by a tear governed by the critical energy release rate (ERR) Gc, which is tissue dependent. Analytical and numerical studies were both conducted indicating the possibility of a safe and effective incision in cataract surgery. Six commonly used IOL injection systems were examined. Our results suggested that the recommended 2.2 mm incision cannot be treated as a universal threshold. Quicker IOL insertion may reduce wound damage. It was also recommended to advance IOL injector via its minor axis, and to cut the tear preferably along the circumferential direction due to tissue orthotropy. This study provides useful information and a deeper insight into the potential for mechanical damage to the corneal wound in cataract surgery.

Should We Perform Early Cataract Surgery? A Patient Reported Outcome Study

Purpose

Current guidance states that access to cataract surgery should not be restricted by visual acuity (VA); nevertheless, 6/12 is used as a cut-off criterion in some health institutions. This study aims to determine the benefits of performing cataract surgery in patients with VA of 6/9 or better in both eyes; determine whether these benefits change over time; and compare the benefit observed between early first eye and second eye surgery.

Patients and Methods

Fifty adults with VA at least 6/9 in the worst eye and no ocular comorbidity were recruited. The Visual Function Index (VF-14) and Impact of Visual Impairment (IVI) questionnaires were conducted pre-operatively, 4 months post-operatively, and 12 months post-operatively. The t-test or a non-parametric equivalent was used to compare averages between groups.

Results

The mean change in VF-14 from baseline to 4 months was 16.43 (95% CI 12.49–20.50, p < 0.001) and the median change in IVI was 6.5 (IQR 9.75, p < 0.001). There was no significant difference between 4-month and 12-month follow-up (p > 0.05). There was no significant difference in the change in visual function between the first and second eye surgery (p > 0.05).

Conclusion

This study provides evidence that visual function improves after cataract surgery in patients with pre-operative VA of 6/9 or better. The improvement observed was clinically significant and unchanged a year after surgery. Visual function improved after second eye as much as after first eye surgery. Assessing patient reported visual function may give a more realistic indication of the benefit of early cataract surgery than relying on VA alone.

Patients' attitudes towards the potential use of stability tape to minimize head movements during cataract surgery

INTRODUCTION

Head stabilization may reduce intra-operative risk during cataract surgery, but could be misinterpreted as "restraint." We wanted to establish patients' attitudes towards the potential use of stability-tape.

MATERIALS AND METHODS

One-hundred consecutive patients attending for local-anaesthetic cataract surgery were asked to complete a pre-operative questionnaire. This explored patient concerns and views regarding intra-operative head movement and the potential use of stability-tape.

RESULTS

All 100-patients completed the questionnaire. The median head movement concern score was 2 out of 10 (range 1-9, IQR 1-5). Eighty-four percent felt stability tape should be offered to all patients and 97% would consent for its' use. Only 6% voiced concern about the use of stability-tape (95% CI 2.2%, 12.6%).

CONCLUSION

Patients had low concern for moving their head during surgery. The concept of stability-tape to minimize head movements during cataract surgery was viewed positively by most patients. This strategy may promote safer surgery in selected cases.

Psychological complexities of visual restoration

In this paper, we report the psychological and emotional experience of a patient who regained vision after over a decade of vision loss. The negative psychological implications of blindness are well recognised and there is a robust link between visual impairment and low mood and depressive symptoms. Although uncommon, low mood and depressive symptoms have been reported in patients whose sight has been restored, and lack of research gives rise to the possibility their prevalence may be grossly under-recognised in such patient groups. The effects can be so severe that patients may revert to living in darkness in mimicry of their previous lifestyle, effectively obviating the sight-restoring surgery. Healthcare professionals have a responsibility to address this traditionally neglected need by facilitating social, psychological and medical interventions that may ease the return to vision.

Virucidal benefits of povidone-iodine use on the ocular surface: a review

Povidone-iodine (PVI) preparations are well known for their microbicidal effect. In ophthalmology, PVI is commonly used to sterilise the ocular surface prior to surgical procedures. It is also used uncommonly as treatment for adenoviral conjunctivitis, yet the virucidal benefits of PVI have not been clearly documented in existing clinical management guidelines for ocular surface conditions. The COVID-19 pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, has challenged traditional healthcare systems. The morbidity and mortality of this highly contagious disease have resulted in fatalities among healthcare workers, including ophthalmologists. The SARS-CoV-2 virus has been identified on conjunctival testing, a potential source of contagious infection which may be unrecognised in asymptomatic carriers. Concern has been raised that ocular procedures may be ‘aerosol-generating’ and the additional wearing of personal protective equipment has been recommended to protect operating theatre staff. This literature review demonstrates that PVI has a broad virucidal activity, including against coronaviruses. It is already used perioperatively as standard of ophthalmic care and has been shown clinically to be effective against adenoviruses on the ocular surface. The current surgical practice of application of 5%–10% PVI applied periocularly for 3 min seems to provide an adequate effective reduction in the patient’s ocular surface viral load. The virucidal benefits of routine PVI use should be included in ophthalmology guidelines regarding safe ocular surgery protocols.

Modelling floppy iris syndrome and the impact of pupil size and ring devices on iris displacement

Introduction

The aim of this paper was to further develop a previously described finite element model which equates clinical iris billowing movements with mechanical buckling behaviour, simulating floppy iris syndrome. We wished to evaluate the impact of pupil dilation and mechanical devices on normal iris and floppy iris models.

Methods

Theoretical mathematical modelling and computer simulations were used to assess billowing/buckling patterns of the iris under loading pressures for the undilated and dilated normal iris, the undilated and dilated floppy iris, and additionally with a mechanical ring device.

Results

For the normal iris, billowing/buckling occurred at a critical pressure of 19.92 mmHg for 5 mm pupil size, which increased to 28.00 mmHg (40.56%) with a 7 mm pupil. The Malyugin ring device significantly increased critical initiating buckling pressures in the normal iris scenario, to 34.58 mmHg (73.59%) for 7 mm ring with boundary conditions I (BC I) and 34.51 mmHg (73.24%) with BC II. For the most floppy iris modelling (40% degradation), initiating buckling value was 18.04 mmHg (−9.44%), which increased to 28.39 mmHg (42.52%) with the 7 mm ring. These results were much greater than for normal undilated iris without restrictive mechanical expansion (19.92 mmHg).

Conclusion

This simulation demonstrates that pupil expansion devices inhibit iris billowing even in the setting of floppy iris syndrome. Our work also provides a model to further investigate the impact of pupil size or pharmacological interventions on anterior segment conditions affected by iris position.

Temporomandibular Disorder: An Important Cause of Temporal Headache in Patients Unlikely to Have Giant Cell Arteritis

INTRODUCTION

Temporal headache often results in an Ophthalmology referral to rule out giant cell arteritis (GCA). When clinical suspicion of GCA is low, alternative diagnoses should be considered. Temporomandibular disorder (TMD) commonly causes a temporal headache.

MATERIALS AND METHODS

Patients referred with a temporal headache attending the Friday emergency ophthalmology clinic from February to July 2017 were assessed for GCA using the American College of Rheumatology (ACR) diagnostic criteria and TMD using a validated screening questionnaire.

RESULTS

Ten symptomatic patients presented and were screened for TMD during this period. Four had mild TMD, two moderate, and three severe. The mean TMD score in patients with less than 3 ACR GCA criteria was 14.75 (SD 4.03) versus 6.8 (SD 3.06) in patients with 3 or more criteria (p = 0.0075).

CONCLUSION

TMD is an important cause of a temporal headache in patients unlikely to have GCA. Onward referral to dentistry for further management may be merited.

Allogeneic Ex Vivo Expanded Corneal Epithelial Stem Cell Transplantation: A Randomized Controlled Clinical Trial

Limbal stem cell deficiency (LSCD) is a disease resulting from the loss or dysfunction of epithelial stem cells, which seriously impairs sight. Autologous limbal stem cell transplantation is effective in unilateral or partial bilateral disease but not applicable in total bilateral disease. An allogeneic source of transplantable cells for use in total bilateral disease can be obtained from culture of donated cadaveric corneal tissue. We performed a controlled multicenter study to examine the feasibility, safety, and efficacy of allogeneic corneal epithelial stem cells in the treatment of bilateral LSCD. Patients were randomized to receive corneal epithelial stem cells cultured on amniotic membrane (AM): investigational medicinal product (IMP) or control AM only. Patients received systemic immunosuppression. Primary endpoints were safety and visual acuity, secondary endpoint was change in composite ocular surface score (OSS). Sixteen patients were treated and 13 patients completed all assessments. Safety was demonstrated and 9/13 patients had improved visual acuity scores at the end of the trial, with no significant differences between IMP and control groups. Patients in the IMP arm demonstrated significant, sustained improvement in OSS, whereas those in the control arm did not. Serum cytokine levels were measured during and after the period of immune suppression and we identified strongly elevated levels of CXCL8 in the serum of patients with aniridia, which persisted throughout the trial. This first randomized control trial of allogeneic corneal epithelial stem cells in severe bilateral LSCD demonstrates the feasibility and safety of this approach. stem cells translational medicine2019;8:323–331

EDTA chelation for symptomatic band keratopathy: results and recurrence

PurposeTo identify causes of symptomatic band keratopathy, and assess the results and long-term recurrence rates following chelation with topical ethylene-diamine-tetra-acetic acid (EDTA).Patients and methodsA retrospective review of surgical logbooks identified patients managed by EDTA chelation for symptomatic band keratopathy from 2009 to 2015.ResultsWe identified 108 cases; 89 case notes were available for analysis. Most cases of band keratopathy were idiopathic (36%). The most commonly identified underlying diagnosis was long-term topical glaucoma therapy (27%). Median presenting visual acuity was 6/18 (range 6/6-NPL) with the visual axis affected in 97.8% of cases. Treatment involved corneal epithelium removal, recurrent application of topical EDTA, and subsequent debridement. The mean duration of the operation was 20 min (range 10-45). Mean initial follow-up time was 40 days, and the visual axis was clear in 97.8%. Visual acuity was maintained or improved in 79.8%, with 13.5% improving by two lines or more. The mean length of follow-up was 581 days (median 374, maximum 2438). Twenty-five eyes (28.1%) showed localised recurrence of calcium with a mean time of 546 days (median 374), but only four cases required repeat EDTA chelation. The median time between operations was 430 days. Thirty-two per cent of the recurrence cases were associated with hypotony or chronic presence of silicone oil.ConclusionsChelation of calcium with topical EDTA is a safe and effective treatment for band keratopathy. Visual acuity improves in most eyes and while the rate of recurrence is moderate, the need for retreatment is low (4.5% overall).

Diagnostic criteria for limbal stem cell deficiency-a systematic literature review

The diagnosis of limbal stem cell deficiency (LSCD) is often based on clinical manifestations with or without the use of tests to demonstrate the presence of goblet cells or of specific epithelial markers on the corneolimbal surface. This systematic review looks at the various diagnostic methods used in the diagnosis of LSCD in published interventional studies. The design is a systematic literature review. We did a systematic search on MEDLINE and PUBMED for articles published in English between January 1, 2003, and December 31, 2013. We collected data on diagnostic methods used to diagnose LSCD (clinical findings, impression cytology, immunohistochemistry for various epithelial markers, or in vivo confocal microscopy). Forty-six studies (mostly retrospective/interventional case series) met the inclusion criteria. All of the studies used clinical features as evidence of LSCD: discomfort, impaired vision, irregular epithelium, unstable tear film, persistent epithelial defects, scarring, fibrovascular pannus, neovascularization, keratinization, calcification, and opacification of the cornea. Eighteen studies (39.1%) used an additional test for the diagnosis; 17 studies (37.0%) used impression cytology for goblet cells, 4 studies (8.7%) used immunohistochemistry for epithelial markers, and 2 studies (4.3%) use in vivo confocal microscopy. The diagnosis of LSCD was made in most cases on clinical grounds alone. In some studies, diagnostic tests were used, but these varied considerably from study to study. Comparison of effectiveness of various interventions requires standardized diagnostic methods. Consensus on the diagnostic criteria for LSCD is essential and needs to be reached by the interested care providers.

Inadvertent Detachment of Descemet Membrane and Spontaneous Reattachment Following Cataract Surgery: An Anterior Segment Optical Coherence Tomography (AS OCT) Study

Corneal oedema following cataract surgery during the immediate postoperative period is a common clinical problem, often due to endothelial injury due to multi-factorial mechanisms. Descemet's membrane detachment (DMD) is an underrecognized cause of postoperative corneal oedema. The understanding of the pathogenic mechanisms of DMD is still evolving. We report a case of DMD in a 64-year-old female presenting with immediate postoperative corneal oedema, diagnosed and monitored using anterior segment optical coherence tomography (AS OCT). Various mechanisms have been proposed for surgically induced DMD. We believe that hydration of surgical wounds at the end of surgery can inadvertently cause DMD, if DMD has not been recognized previously. Surgeons should be alert to this cause of DMD when hydrating surgical wounds.

Treatment of corneal cystine crystal accumulation in patients with cystinosis

Cystinosis is a rare autosomal recessive disorder characterized by the accumulation of cystine within the cells of different organs. Infantile nephropathic cystinosis is the most common and severe phenotype. With the success of renal transplantation, these patients are now living longer and thus more long-term complications within different organs are becoming apparent. Ophthalmic manifestations range from corneal deposits of cystine crystals to pigmentary retinopathy. With increasing age, more severe ocular complications have been reported. Photophobia is a prominent symptom for patients. With prolonged survival and increasing age, this symptom, along with corneal erosions and blepharospasm, can become debilitating. This review revisits the basic pathogenesis of cystinosis, the ocular manifestations of the disease, and the treatment of corneal crystals.

Differentiation and molecular profiling of human embryonic stem cell-derived corneal epithelial cells

It has been suggested that the isolation of scalable populations of limbal stem cells may lead to radical changes in ocular therapy. In particular, the derivation and transplantation of corneal stem cells from these populations may result in therapies providing clinical normality of the diseased or damaged cornea. Although feasible in theory, the lack of donor material in sufficient quantity and quality currently limits such a strategy. A potential scalable source of corneal cells could be derived from pluripotent stem cells (PSCs). We developed an in vitro and serum-free corneal differentiation model which displays significant promise. Our stepwise differentiation model was designed with reference to development and gave rise to cells which displayed similarities to epithelial progenitor cells which can be specified to cells displaying a corneal epithelial phenotype. We believe our approach is novel, provides a robust model of human development and in the future, may facilitate the generation of corneal epithelial cells that are suitable for clinical use. Additionally, we demonstrate that following continued cell culture, stem cell-derived corneal epithelial cells undergo transdifferentiation and exhibit squamous metaplasia and therefore, also offer an in vitro model of disease.

Increased corneal epithelial turnover contributes to abnormal homeostasis in the Pax6(+/-) mouse model of aniridia

We aimed to test previous predictions that limbal epithelial stem cells (LESCs) are quantitatively deficient or qualitatively defective in Pax6^+/− mice and decline with age in wild-type (WT) mice. Consistent with previous studies, corneal epithelial stripe patterns coarsened with age in WT mosaics. Mosaic patterns were also coarser in Pax6^+/− mosaics than WT at 15 weeks but not at 3 weeks, which excludes a developmental explanation and strengthens the prediction that Pax6^+/− mice have a LESC-deficiency. To investigate how Pax6 genotype and age affected corneal homeostasis, we compared corneal epithelial cell turnover and label-retaining cells (LRCs; putative LESCs) in Pax6^+/− and WT mice at 15 and 30 weeks. Limbal BrdU-LRC numbers were not reduced in the older WT mice, so this analysis failed to support the predicted age-related decline in slow-cycling LESC numbers in WT corneas. Similarly, limbal BrdU-LRC numbers were not reduced in Pax6^+/− heterozygotes but BrdU-LRCs were also present in Pax6^+/− corneas. It seems likely that Pax6^+/− LRCs are not exclusively stem cells and some may be terminally differentiated CD31-positive blood vessel cells, which invade the Pax6^+/− cornea. It was not, therefore, possible to use this approach to test the prediction that Pax6^+/− corneas had fewer LESCs than WT. However, short-term BrdU labelling showed that basal to suprabasal movement (leading to cell loss) occurred more rapidly in Pax6^+/− than WT mice. This implies that epithelial cell loss is higher in Pax6^+/− mice. If increased corneal epithelial cell loss exceeds the cell production capacity it could cause corneal homeostasis to become unstable, resulting in progressive corneal deterioration. Although it remains unclear whether Pax6^+/− mice have LESC-deficiency, we suggest that features of corneal deterioration, that are often taken as evidence of LESC-deficiency, might occur in the absence of stem cell deficiency if corneal homeostasis is destabilised by excessive cell loss.

Deep anterior lamellar keratoplasty: challenges in histopathological examination

BACKGROUND/AIMS

To characterise histopathological changes in corneal buttons associated with deep anterior lamellar keratoplasty (DALK).

METHODS

This was a retrospective, clinical laboratory study. All recipient corneal buttons that underwent DALK in the West of Scotland and were submitted to the regional Ocular Pathology Laboratory (Glasgow, UK) between 2001 and 2010 were examined. Cases affected by artefacts secondary to DALK were highlighted. Keratoconus cases that underwent DALK were compared to those that underwent penetrating keratoplasty (PK).

RESULTS

225 DALK corneal buttons were examined. Of these, 61.8% were affected by artefacts or problems related to DALK. Overall, 58.2% of the affected buttons were affected by corneal emphysema related to intrastromal air injection (the 'big bubble' technique), 5.3% by epithelial oedema related to the hydrodelamination procedure, which mimicked bullous keratopathy secondary to endothelial cell deficiency, and 0.9% were lost specimens. We were not able to identify any conus, which is a characteristic histopathological feature of keratoconus, in 10 (7.4%) of the DALK-keratoconus cases as opposed to two (1.6%) of the PK-keratoconus cases (p=0.036).

CONCLUSIONS

DALK poses new challenges for histopathological examination of corneal buttons. Awareness of DALK-related histopathological characteristics should be raised among ocular pathologists and ophthalmologists in view of the increasing popularity of this technique.

Long term visual outcomes, graft survival and complications of deep anterior lamellar keratoplasty in patients with herpes simplex related corneal scarring

AIMS

To report long term visual outcomes, complications and graft survival of patients undergoing deep anterior lamellar keratoplasty (DALK) to treat corneal scarring secondary to herpes simplex virus (HSV) keratitis.

METHODS

Retrospective, non-comparative case series. 18 patients who underwent DALK for HSV keratitis related corneal scarring between January 2004 and February 2007 were included. DALK was performed by Anwar's big bubble technique. Data collected for analysis included preoperative characteristics, intraoperative complications and postoperative acuity, complications and subsequent operations.

RESULTS

Mean best corrected distance visual acuity (LogMAR) improved from 1.51 ± 0.90 preoperatively to 0.82 ± 0.85 at the last follow-up (p=0.05). 27% of patients with more than 4 years follow-up had a best corrected distance visual acuity of 6/12 or better and 64% were 6/24 or better. Six patients (33%) experienced a recurrence of HSV keratitis and 9 (50%) experienced an episode of graft rejection. There were five cases (28%) of graft failure, four of whom had had a previous episode of graft rejection. Logistic regression did not find an association with graft rejection, HSV recurrence, any other observed postoperative host corneal vascularisation and any postoperative complication. The majority of patients underwent a second operation with 50% requiring cataract surgery.

CONCLUSIONS

DALK for the treatment of HSV related corneal scarring is associated with a high percentage of postoperative complications. DALK in this context is also associated with a large percentage of secondary operations. Patients should be aware of this when giving informed consent for DALK to treat HSV related corneal scars.

Effects of N-acetylcysteine on matrix metalloproteinase-9 secretion and cell migration of human corneal epithelial cells

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) secreted by corneal epithelial cells has a role in the remodelling of extracellular matrix and migration of epithelial cells. Elevated levels of MMP-9 activity in the ocular surface may be involved in the pathogenesis of corneal diseases. N-acetylcysteine (NAC) has been used to treat corneal diseases, including recurrent epithelial erosions. In this study, its effects on the MMP-9 secretion and human corneal epithelial (HCE) cell migration were evaluated in vitro.

METHODS

Confluent HCE cell cultures were treated with 0-20 mM NAC, and tested for MMP-9 secretion and epithelial cell migration by gelatin zymography and scratch wound assay, respectively. Comparisons between different treatment groups were made using analysis of variance, followed by multiple pairwise comparisons.

RESULTS

Twenty mM NAC inhibited the secretion of MMP-9 significantly. Cell migration, assessed after 24 h of wounding, showed a highly significant dose-dependent inhibitory effect.

CONCLUSIONS

This study shows that NAC reduces MMP-9 production by HCE cells and inhibits cell migration in vitro. This information helps to elucidate the mechanisms by which NAC may be beneficial therapeutically and suggests that NAC may be useful for managing corneal erosions and related conditions.

Corneal Endothelium in Brown-McLean syndrome: in-vivo confocal microscopy finding

When Brown-McLean syndrome (BMS) was first described, there was no confocal microscopy to document corneal endothelial status, and it was understood as a disease entity involving a diseased endothelial layer. In the advent of confocal microscopy demonstrating healthy endothelium in BMS within the affected cornea, it can be inferred that BMS is a spectrum of disease ranging from healthy to decompensated corneal endothelium, rather than just a specific disease entity. Here we report a case of BMS with normal healthy corneal endothelium using corneal confocal microscopy. Any patient with BMS should be followed up to observe for any disease progression and should be educated regarding the signs and symptoms of corneal surface problems. Confocal microscopy documentation is a convenient and informative way and should form part of the follow-up of any BMS patient.

Molecular profile of organ culture-stored corneal epithelium: LGR5 is a potential new phenotypic marker of residual human corneal limbal epithelial stem cells

Long-term preservation of corneal limbal epithelium may decrease its quality and change the molecular signature of the limbal epithelial stem cells. In this study we have investigated the molecular profile of isolated corneal epithelial cells that have been in storage for an extended time. Isolated cells were characterised by the expression profile of different cytokeratins and markers of squamous metaplasia (vimentin and α‑actin). Furthermore, we examined global markers of adult stem cells including p63α and ABCG2 but also LGR5 as a novel stem cell marker. Immunocytochemical staining and PCR analysis of p63α, ABCG2 and LGR5 revealed the existence of side-population cells with a stem-cell phenotype and maintenance of corneal limbal stem cell properties. LGR5 expression can be related to cellular stemness and can be considered as a new phenotypic marker of residual human corneal limbal stem cells. However, the existence of CK10 together with co-expressed α-actin and vimentin suggests that the corneas investigated were under oxidative stress and showed evidence of squamous metaplasia.

The patterns of in vitro antimicrobial susceptibility and resistance of bacterial keratitis isolates in Glasgow, United Kingdom

PURPOSE

Trends in antibiotic sensitivity of pathogenic bacteria change with time and the emergence of resistance to commonly used antibiotics is not uncommon. The aim of this study is to identify the antibiotic susceptibility and resistance patterns in a tertiary referral centre that commonly manages corneal infections.

METHODS

This is a retrospective review of microbiology reports of corneal scrapes in a tertiary care hospital.

RESULTS

There were 205 positive corneal scrapes (32 per cent) in 1995 to 1998 and 147 (28 per cent) in 2004 to 2007. There was increased incidence of Staphylococcus aureus (18 to 21 per cent) (p = 0.16), Moraxella catarrhalis (1.5 to 5 per cent) (p = 0.5), pseudomonas species (6 to 14.5 per cent) (p = 0.25) and non-lactose fermenting coliforms (1.5 to 7 per cent) (p = 0.5). In vitro resistance of gram-positive bacterial isolates to ciprofloxacin was increased from 5 to 7 per cent (p = 0.5). The in vitro susceptibility of gram-positive organisms to dual therapy with cefuroxime and gentamicin were 98 per cent in 1995 to 1998, and 94 per cent in 2004 to 2007 (p = 0.1). Pseudomonas species were 100 per cent susceptible to cefuroxime in the first period but developed 100 per cent resistance in the later period (p = 0.0002). However, the susceptibility of gram negative bacterial isolates to dual therapy with cefuroxime and gentamicin (p = 1) and monotherapy with ciprofloxacin (p = 1) was 100 per cent in both periods. The in vitro resistance to chloramphenicol to gram-positive organisms was reduced to 5 from 12 per cent (p = 0.19) but there was an increase in resistance of gram-negative organisms from 23 to 36 per cent (p = 0.3).

CONCLUSION

Despite limitations, this study demonstrates that the fortified antibiotics such as 5% cefuroxime 1.5% gentamicin may be the appropriate choices for most episodes of bacterial keratitis, either as an initial therapy or after identification of in vitro susceptibility of bacterial isolates.

The outcome of deep anterior lamellar keratoplasty in herpes simplex virus-related corneal scarring, complications and graft survival

AIMS

To determine the visual outcome, graft survival and complications after deep anterior lamellar keratoplasty (DALK) in patients with herpes simplex virus (HSV)-related corneal scarring.

METHODS

A retrospective analysis of the patients who had DALK for HSV-related corneal scarring between January 2004 and February 2007 was performed. Mean follow-up was 30 months (range 16-48 months). The statistical significance of host corneal vascularisation was determined using Fisher's exact test.

RESULTS

There were 18 eyes from 18 patients and the mean age was 57 years. Preoperative visual acuity ranged from hand movements (HM) to 6/12. Fifty per cent of the eyes achieved visual acuity of 6/12 or better postoperatively. Six eyes (33%) had recurrence of HSV-related inflammation, eight eyes (including four eyes with recurrence of HSV-related inflammation) developed graft rejection and four eyes (including two eyes with recurrence of HSV-related inflammation) had bacterial keratitis. The graft survival rate was 83%. Three eyes developed glaucoma and one eye required trabeculectomy. Immunohistochemistry revealed that HSV was focally positive or equivocal in four recipient corneal buttons, and transmission electron microscopy showed intracellular HSV virions in two of them.

CONCLUSIONS

This is the largest series of DALK for herpetic corneal scarring that shows a comparable visual outcome and better graft survival rate than penetrating keratoplasty. There is significant risk of recurrence of HSV-related inflammation and graft rejection that requires timely recognition and adequate management.

Superior forniceal advancement conjunctival pedicle (SFACP) in the management of corneal perforations and impending perforations due to rheumatoid arthritis related autoimmune corneal melts

Peripheral ulcerative keratitis (PUK) is a disorder consisting of a crescent-shaped destructive inflammation of the perilimbal corneal stroma. PUK may occur in variety of systemic diseases including collagen vascular disease. We describe the outcome of superior forniceal advancement conjunctival pedicle (SFACP) in two patients with corneal perforation and impending perforation due to rheumatoid arthritis (RA) related auto immune corneal melt that has not previously been reported. Both patients had good recovery with restoration of vision when SFACP was performed as an adjunct to systemic immunosuppressive agents. SFACP is a valuable surgical option which may have an important role in reducing progression of corneal melt and underlying disease when used along with adequate systemic immunosuppressive agents.