Improved impression cytology techniques for the immunopathological diagnosis of superficial viral infections

Impression cytology's reliability as an effective method for ophthalmic neoplasm detection

Background:

The current investigation was intended to evaluate the precision of impression cytology and tissue histology in the detection of ocular surface neoplasia.

Materials and Methods:

We examined the histories of patients detected with ocular surface neoplasia at the Department of Ophthalmology, Kalinga Institute of Medical Sciences, Bhubaneswar. All the patients had their impressions cytology and tissue samples taken. The outcomes of both strategies were compared.

Results:

There were a total of 55 patients (33 males and 22 females) aged 12–99 years (average age, 51 years). Twenty patients had injuries to the right eye and 35 had injuries to the left eye. Conjunctival–corneal intraepithelial neoplasia (38.2%), squamous cell carcinoma (34.5%), squamous epithelium (10.9%), squamous papilloma (7.3%), conjunctival nevi (7.3%), Along with the most common histological research, malignant melanoma (1.8%). Compared with the histological results, impression cytology showed positive and negative assessment accuracies of 97.4% and 52.9%, respectively. In squamous neoplasms, squamous cell carcinoma exhibited a strong link with histology. The occurrence of dysplastic cells raised suspicion of malignancy.

Conclusion:

Because of its increased accuracy in detecting lesions, along with tissue histology, impression cytology exhibits enormous potential in identifying ocular surface neoplasia. However, impression cytology has an undesirable prognostic accuracy, indicating that it is a useful screening tool but cannot be considered as a “gold standard.”

Diagnostic armamentarium of infectious keratitis: A comprehensive review

Infectious keratitis (IK) represents the leading cause of corneal blindness worldwide, particularly in developing countries. A good outcome of IK is contingent upon timely and accurate diagnosis followed by appropriate interventions. Currently, IK is primarily diagnosed on clinical grounds supplemented by microbiological investigations such as microscopic examination with stains, and culture and sensitivity testing. Although this is the most widely accepted practice adopted in most regions, such an approach is challenged by several factors, including indistinguishable clinical features shared among different causative organisms, polymicrobial infection, long diagnostic turnaround time, and variably low culture positivity rate. In this review, we aim to provide a comprehensive overview of the current diagnostic armamentarium of IK, encompassing conventional microbiological investigations, molecular diagnostics (including polymerase chain reaction and mass spectrometry), and imaging modalities (including anterior segment optical coherence tomography and in vivo confocal microscopy). We also highlight the potential roles of emerging technologies such as next-generation sequencing, artificial intelligence-assisted platforms. and tele-medicine in shaping the future diagnostic landscape of IK.

Cellular Imprinting Proteomics Assay: A Novel Method for Detection of Neural and Ocular Disorders Applied to Congenital Zika Virus Syndrome

Congenital Zika syndrome was first described due to increased incidence of congenital abnormalities associated with Zika virus (ZIKV) infection. Since the eye develops as part of the embryo central nervous system (CNS) structure, it becomes a specialized compartment able to display symptoms of neurodegenerative diseases and has been proposed as a noninvasive approach to the early diagnosis of neurological diseases. Ocular lesions result from defects that occurred during embryogenesis and can become apparent in newborns exposed to ZIKV. Furthermore, the absence of microcephaly cannot exclude the occurrence of ocular lesions and other CNS manifestations. Considering the need for surveillance of newborns and infants with possible congenital exposure, we developed a method termed cellular imprinting proteomic assay (CImPA) to evaluate the ocular surface proteome specific to infants exposed to ZIKV during gestation compared to nonexposure. CImPA combines surface cells and fluid capture using membrane disks and a large-scale quantitative proteomics approach, which allowed the first-time report of molecular alterations such as neutrophil degranulation, cell death signaling, ocular and neurological pathways, which are associated with ZIKV infection with and without the development of congenital Zika syndrome, CZS. Particularly, infants exposed to ZIKV during gestation and without early clinical symptoms could be detected using the CImPA method. Lastly, this methodology has broad applicability as it could be translated in the study of several neurological diseases to identify novel diagnostic biomarkers. Data are available via ProteomeXchange with identifier PXD014038.

Impression cytology for detection of clinically suspected ocular surface disorders: A cross-sectional study

PURPOSE

Investigating impression cytology (IC) results of various types of clinically suspected ocular surface lesions over a 14-year period in a referral center in Iran.

METHODS

IC findings obtained from patients with different types of ocular surface disorders between 2005 and 2018 were reviewed. Agreement between clinical suspicions and IC results was evaluated by calculating Cohen's Kappa coefficient (CKC).

RESULTS

Clinical suspicions in 688 surveyed eyes were ocular surface squamous neoplasia (OSSN, 42.0%), limbal stem cell deficiency (LSCD, 36.3%), dry eye-related disorders (DERD, 11.5%), Acanthamoeba keratitis (AK, 7.2%), benign pigmented lesions (BPL, 1.9%), immune-related conjunctivitis (IRC, 0.7%), and malignant pigmented lesions (MPL, 0.4%). General agreement between clinical suspicions and IC results was 0.68 for all groups. This agreement was almost perfect in AK (CKC = 0.966) and BPLs (CKC = 0.843), and was substantial in MPLs (CKC = 0.749), OSSNs (CKC = 0.684), and LSCD (CKC = 0.612). CKC in IRC (0.567) and DERDs (0.443) was moderate. Histopathologic results were available in 22 eyes and were well-correlated with corresponding IC results (CKC = 0.86). Multiple post-treatment follow-up sessions of IC were performed in 51 eyes (11.4%) that had diagnosis of LSCD (31), OSSN (17), and MPL (3) at the first IC session.

CONCLUSION

Our survey not only demonstrated an overall substantial agreement between IC results and primary clinical suspicions, but also showed an almost perfect correlation between IC results and existent histopathologic data. Therefore, IC as a non-invasive diagnostic modality can be of great importance in proper diagnosis of various ocular surface diseases especially when distinguishing malignant from benign lesions is required.

Use of a corneal impression membrane and PCR for the detection of herpes simplex virus type-1

Purpose. To investigate the use of a corneal impression membrane (CIM) for the detection of herpes simplex virus type 1 (HSV-1) in suspected herpes simplex keratitis (HSK).Methodology. In the laboratory study, swabs and CIMs made from polytetrafluoroethylene were spiked with different concentrations of HSV-1. DNA was extracted and real-time PCR undertaken using two sets of primers. In the clinical study, consecutive patients presenting with suspected HSK were included. For each patient, samples were collected from corneal lesions with a swab and a CIM in random order. Clinical details were collected using a standardized clinical form and patients were categorized into probable, presumed and possible HSK.Results. There was no difference in the performance of both primer sets for all HSV-1 dilutions (P=0.83) using a CIM or between a CIM and a swab (P=0.18). In total, 110 patients were included. Overall, 73 patients (66.4 %) had probable, 20 patients (18.2 %) presumed and 17 patients (15.5 %) possible HSV-1 keratitis. The HSV-1 detection rate was significantly higher using a CIM (40/110, 36.4 %) than a swab (28/110, 25.5 %) (P=0.004). In the probable HSV keratitis group, the detection rate using a CIM was 43.8 % compared to 27.4 % for a swab (P=0.004). The cycle threshold values obtained for the conjunctival swabs were higher than those obtained for the CIMs (P<0.001).Conclusions. In suspected HSK, a CIM is a useful alternative to a swab and more likely to detect the presence of HSV-1.

Characterisation of corneal impression cytology in dogs and its application in the diagnosis of keratoconjunctivitis sicca

OBJECTIVE

Determine morphological and morphometric parameters of corneal epithelium in dogs, and determine the cellular alterations that occur in canine keratoconjunctivitis sicca (KCS) using impression cytology.

STUDY ANIMALS

60 dogs divided into two groups: dogs with Schirmer tear test (STT) at least 15 mm/minute and absence of ocular disease, and dogs with STT less than 15 mm/minute and clinical signs of KCS.

PROCEDURES

Impression cytology was used to collect corneal samples. The percentage of eyes with cell changes, the number of such cells and the percentage of cells with structural alterations in each group were determined. The possible correlation between corneal epithelium alterations and decreased tear production was evaluated.

RESULTS

A significant positive correlation existed between STT and the area of the cytoplasm and nucleus of corneal cells. A significant negative correlation was found between STT ​​and the nucleus/cytoplasm ratio, and the presence of cellular changes. A significant difference existed between the numbers of pyknotic nuclei, being higher among animals with all stages of KCS.

CONCLUSION

Corneal impression cytology can be used to assess the corneal epithelium in healthy eyes and eyes with KCS, demonstrating its usefulness as a diagnostic tool especially in mild and early cases.

Rituximab and bilateral HSV epithelial keratitis in a patient with mucous membrane pemphigoid

Background

B cell depleting therapy is widely used for lymphoproliferative diseases and immune-mediated disorders, including mucous membrane pemphigoid. The latter is an autoimmune blistering disease affecting predominantly the mucosae potentially associated with devastating complications.

Methods

A 71-year-old patient with severe mucous membrane pemphigoid involving ocular, oral pharyngeal and laryngeal involvement is described. To control the disease, the patient was given rituximab therapy in combination with oral corticosteroids. He subsequently experienced an epithelial herpes simplex virus keratitis in one eye and 3 months later in his fellow eye. Topical treatment with ganciclovir resulted in prompt recovery.

Results

For the first time, a correlation between rituximab and bilateral epithelial herpes simplex virus keratitis is described.

Conclusions

Although rituximab is a promising biologic agent for the treatment of autoimmune diseases, it bears the risk of reactivation of viral infections, including the onset of herpes simplex virus keratitis.

Effect of storage time and temperature on the detection of Pseudomonas aeruginosa, Acanthamoeba and Herpes Simplex Virus from corneal impression membranes

The effect of storage time and temperature on the recovery of pathogen DNA from polytetrafluorethylene (PTFE) was investigated. PTFE impression membranes were inoculated with Pseudomonas aeruginosa, Herpes Simplex Virus-1 (HSV-1) or Acanthamoeba and stored at -70 °C, -20 °C, +4 °C or +35 °C. PCR was performed on days 0, 1, 2, 3, 7 and months 1, 3 and 10 post-inoculation. We found no reduction in the DNA recovery of any of the studied microorganisms for the first 3 days of storage up to +35 °C. For HSV-1 and P. aeruginosa, storage for 3 months at +35 °C was associated with a significant reduction in DNA recovery (P<0.001), but not at +4 °C, -20 °C or -70 °C for 1 month for P. aeruginosa and for 10 months for HSV-1. Acanthamoeba DNA recovery was not affected by any storage parameters (P=0.203). These results will inform the investigation of microbial keratitis where access to microbiological testing is not readily available.

Ocular Surface Changes After Sulfur Mustard Exposure in Rabbits, Monitored by Impression Cytology

PURPOSE

Ocular injuries after exposure to sulfur mustard (SM) are characterized by acute corneal erosion and inflammation of the anterior segment that may be followed by delayed corneal neovascularization and epithelial defects, associated with limbal stem cell deficiency in part of the exposed eyes. This study aimed to further clarify the mechanism of the late injury by monitoring SM-induced cytological alterations in the ocular surface, in relation to the clinical symptoms, using impression cytology (IC).

METHODS

Rabbit eyes were exposed to SM vapor (n = 20) and were clinically observed up to 4 weeks. Samples for IC were collected simultaneously from the upper bulbar conjunctiva, limbus, and cornea and then fixed and stained with periodic acid-Schiff and hematoxylin. At 1 month, animals were killed and eyes dissected and processed for histology.

RESULTS

Concomitant with clinical symptoms of SM ocular toxicity, IC showed significant long-term loss of conjunctival goblet cells shortly after exposure, followed by abnormal differentiation toward squamous metaplasia. Simultaneously with corneal erosion, apoptotic bodies and cellular debris were seen in the corneal epithelium, followed by regeneration at 1 week. Migration of conjunctival goblet cells toward the cornea was noted in neovascularized eyes, as early as 1 week, indicating limbal stem cell deficiency. The IC findings were supported by histological evaluation.

CONCLUSIONS

Continuous monitoring of the ocular surface after SM exposure by IC enables earlier detection of pathology and therapeutic intervention, therefore, is recommended for routine follow-up of casualties. Prolonged loss of goblet cells may point toward the role of mucin in the pathogenesis.

Impression Cytology of Melanocytic Conjunctival Tumors Using the Biopore Membrane

Purpose

To compare a new Biopore membrane impression cytology method with the routinely used exfoliative cytology in patients with a melanocytic lesion of the conjunctiva.

Methods

Sixty-eight consecutive patients with a conjunctival melanocytic lesion underwent Biopore membrane impression cytology as well as exfoliative cytology. A histologic sample was also available in 26 cases. All Biopore samples were stained immediately with RAL 555. Both Biopore and exfoliative cytology samples were assessed by two cytopathologists and graded into four different categories of atypia.

Results

Twenty-three out of 26 Biopores and 20 out of 24 for the exfoliative smears correlated with the corresponding histologic sample. Biopore cytology resulted in higher numbers of cells with a greater density compared to exfoliative cytology.

Conclusions

Biopore cytology can be used for cytologic sampling of conjunctival melanocytic lesions. Because of the larger amount and higher density of cells obtained with the Biopore membrane, interpretation by a pathologist is easier and faster. Sampling of the fornix, caruncula, and ocular material in children is difficult with the Biopore method, and exfoliative cytology seems to be the favorable test in those situations.

Cytology of the healthy canine and feline ocular surface: comparison between cytobrush and impression technique

BACKGROUND

Impression cytology (IC) is a noninvasive technique in which filters are used to sample superficial layers of ocular epithelium.

OBJECTIVES

The aim of this study was to compare cytology specimens obtained by IC and cytobrush from healthy canine and feline eyes.

METHODS

Dogs and cats were prospectively sampled using polytetrafluorethylene filters on the right eye, and cytobrush on the left eye. Wright-Giemsa-stained specimens were evaluated by 2 observers. Cellularity, preservation, and morphology of cells and presence of goblet and inflammatory cells were scored with a 4-grade scale. Inter-observer agreement and effects of topical anesthesia were analyzed.

RESULTS

In 20 canine IC samples, 10 showed good cellularity (score 2-3) and 13 good preservation. Superficial epithelial cells (SEC) were present in 13/20 of IC, while basal-intermediate cells (BIC) were seen in 14/20. In 6/20 and 7/20, goblet and inflammatory cells were noted, respectively. In 20 cats, 15 of IC showed good cellularity and 14 good preservation, and SEC were present in 16/20 of IC and BIC in 17/20. In 13/20 and 3/20 cats, goblet cells and inflammatory cells were noted, respectively. Canine cytobrush specimens appeared well preserved (9/20) and had good cellularity (8/20). In feline cytobrush specimens, good preservation and cellularity were observed in 16/20 and 14/20, respectively. In both species, all cell types were present without a clear separation. There was moderate to fair agreement about cellular morphology in IC between observers. Specimens obtained with and without anesthesia were comparable.

CONCLUSION

Impression cytology allowed collection of samples with maintained cytoarchitecture, while cytoplasmatic and nuclear details were often difficult to evaluate.

On the Variability in Goblet Cell Density in Human Bulbar Conjunctival Samples Collected by Impression Cytology with Millicell-CM Biopore Membrane Units

PURPOSE

To assess whether or not the numbers of goblet cells were different across regions of a conjunctival impression cytology (CIC) specimen.

METHODS

CIC specimens were obtained from the exposed nasal bulbar conjunctiva from 22 healthy young Caucasian adults, stained with Giemsa and evaluated at a final magnification of 200× (medium power fields). Up to 14 different non-overlapping microscope fields, depending on whether or not a field was without goblet cells, were randomly selected.

RESULTS

A microscope field could contain between 0 and 145 goblet cells. If only fields that included goblet cells were analyzed, the mean goblet cell counts (22 specimens, 10 fields/specimen) ranged from 37.8 to 44.8/field (equivalent to 259-313 goblet cells/mm²). When 3, 5 or 10 fields were used to calculate average goblet cell counts for each specimen, the standard deviation values were between 15.8/field and 21.7/field, with the lower values obtained if 10 fields were used. The resultant averaged inter-sample variability, as the coefficient of variation (COV), ranged from 40.0% to 57.5%, while the averaged intra-sample variability in counts ranged from 52.1% to 73.9%. If fields without goblet cells were also used, the resultant mean goblet cell count (from 10 fields/specimen) was statistically lower at 33.1/field (232 goblet cells/mm²).

CONCLUSIONS

These analyses confirm various subjective comments made by early CIC investigators; the distribution of goblet cells across a CIC filter may be highly variable.

Effects of azithromycin on gene expression profiles of proinflammatory and anti-inflammatory mediators in the eyelid margin and conjunctiva of patients with meibomian gland disease

IMPORTANCE

Topical application of azithromycin suppresses expression of proinflammatory mediators while restoring transforming growth factor β1 (TGF-β1) levels as evaluated by eyelid margin and conjunctival impression cytology.

OBJECTIVE

To explore the effects of azithromycin therapy on expression of proinflammatory and anti-inflammatory mediators in meibomian gland disease (MGD).

DESIGN, SETTING, AND PARTICIPANTS

Case-control study performed in a clinic setting from August 17, 2010, to December 31, 2010. Sixteen patients with posterior blepharitis and conjunctival inflammation due to MGD were treated with azithromycin, 1%, drops for 4 weeks. Impression cytology of the lower eyelid margin and tarsal conjunctiva to measure cytokine expression by quantitative real-time polymerase chain reaction as well as tear collection to measure matrix metalloproteinase 9 (MMP-9) activity were performed once in 8 asymptomatic healthy control participants and 5 times in the 16 symptomatic patients (every 2 weeks for 8 weeks), before, during, and after azithromycin treatment.

EXPOSURE

Azithromycin, 1%, drops for 4 weeks.

MAIN OUTCOMES AND MEASURES

Cytokine expression in the eyelid margin and conjunctiva, and MMP-9 activity in tears.

RESULTS

Compared with a 1-time measurement of 8 healthy participants, among 16 symptomatic patients, the mean (SD; 95% CI) fold change of expression of proinflammatory mediators interleukin 1β (IL-1β), IL-8, and MMP-9 increased to 13.26 (4.33; 11.14-15.38; P < .001), 9.38 (3.37; 7.73-11.03; P < .001), and 13.49 (4.92; 11.08-15.90; P < .001), respectively, in conjunctival cells and to 11.75 (3.96; 9.81-13.69; P < .001), 9.31 (3.28; 7.70-10.92; P < .001), and 11.52 (3.50; 9.81-13.24; P < .001), respectively, in the eyelid margin of patients with MGD. In contrast, the mean (SD; 96% CI) fold change of expression of TGF-β1 messenger RNA (mRNA) decreased to 0.58 (0.25; 0.46-0.70; P = .02) and 0.63 (0.14; 0.56-0.70; P = .02) in conjunctival and eyelid margin cells, respectively, of patients with MGD. Azithromycin, 1%, caused a change in the expression pattern of these mediators toward normal levels during 4 weeks of treatment. Levels of IL-1β, IL-8, and MMP-9 mRNA remained suppressed, although they rebounded toward pretreatment values 4 weeks after azithromycin withdrawal. Expression of TGF-β1 increased during treatment and remained at levels similar to the healthy controls after drug withdrawal. Change in tear MMP-9 activity was similar to the pattern of MMP-9 transcripts.

CONCLUSIONS AND RELEVANCE

While the study did not control for potential confounding factors over time independent of the intervention that may have contributed to the results, topical azithromycin suppressed expression of proinflammatory mediators and increased expression of TGF-β1 to normal levels. Increased TGF-β1 expression may contribute to the anti-inflammatory activity of azithromycin in MGD.

Impression membrane for the diagnosis of microbial keratitis

PURPOSE

To evaluate a corneal impression membrane (CIM) for isolation of bacteria, fungi and acanthamoeba in suspected microbial keratitis.

METHODS

Consecutive patients presenting with suspected microbial keratitis were included. For each patient, samples were collected in a random order using a surgical blade and a 4-mm-diameter polytetrafluoroethylene CIM disc, and transported in brain heart infusion broth. Risk factors, best corrected visual acuity (BCVA), size, location, depth and healing time of the ulcer were recorded. The microbial isolation rate was used to compare sampling methods.

RESULTS

130 patients were included (mean age 62.6 years, SD 19.0). An antimicrobial had been used prior to presentation in 36 (27.7%) patients. Mean major and minor ulcer diameters were 2.1 mm (SD 2.0) and 1.6 mm (SD 1.7). Mean healing time was 12.4 days (SD 13.6). BCVA at presentation and following healing was 0.7 (SD 0.7) and 0.62 (SD 0.7) (p=0.34). There were 66 isolates (50.8%); 53 (40.8%) using a CIM and 35 (26.9%) using a blade (p=0.02). ITALIC! Staphylococcus aureus and coagulase-negative staphylococci were the commonest isolates. Isolation rate was not influenced by organism type, although in four cases ITALIC! Acanthamoeba spp. were isolated; three using CIM and one a blade.

CONCLUSIONS

In this study, the isolation of microorganisms from cases of suspected microbial keratitis was significantly higher using a CIM than a surgical blade. A CIM may be a useful alternative or addition for sample collection in microbial keratitis.

Techniques, indications and complications of corneal debridement

The cornea is the most exposed surface of the eye and, as such, is vulnerable to external trauma and the risk of infection. Many corneal diseases alter shape, surface, and transparency and thus result in reduced vision. The external position of the cornea, however, lends itself to diagnostic and therapeutic maneuvers that are commonly performed and readily done in the clinic. More sophisticated techniques require the use of complex equipment such as excimer and femtosecond laser. Complications that develop from poor healing and/or secondary infection are best avoided with appropriate technique, antisepsis, and modification of wound healing. We review corneal debridement in the management of corneal disease.

HLA-DR expression as a biomarker of inflammation for multicenter clinical trials of ocular surface disease

There are currently no validated minimally invasive objective metrics for the classification and evaluation of ocular surface diseases and/or for evaluating treatment efficacy. We thus sought to establish a standardized methodology for determining the relative amount of the inflammatory biomarker HLA-DR on the ocular surface and to evaluate the precision, reliability and repeatability of its use for large multicenter clinical trials and translational research studies of ocular surface disease. Multiple studies were conducted to establish a Standard Operating Procedure (SOP) for utilizing HLA-DR expression as a minimally invasive, objective, ocular surface inflammatory biomarker. The established SOPs provide specific guidelines for HLA-DR collection and analysis, in order to incorporate it reliably into multicenter clinical trials and/or translational research. Duplicate cell samples from impression cytology (IC) samples of both normal and dry eye individuals were collected and split to assess repeatability (between the splits and between the duplicate samples). To determine storage capability, one duplicate was stained immediately and the other after 30 days cold storage. To demonstrate the feasibility of the use of the SOP for a multicenter clinical trial, clinicians out-of-state were trained to collect IC samples, and the samples shipped to our Biomarker Laboratory, logged, processed and analyzed. Demonstration of the ability to incorporate of IC into a randomized double masked clinical trial of dry eye disease (DED) was performed. In all cases, processing and analyses were performed by a masked independent observer. The validity/viability of the SOPs was established by demonstrating that: 1) sufficient numbers of cells can be collected via IC; 2) the precision/repeatability of the relative biomarker expression quantified in samples; 3) personnel at distant sites can be taught to collect, store and ship samples successfully; 4) samples can be stored for up to 30 days (refrigeration) before processing without affecting results; 5) IC can be incorporated into a double blind randomized clinical trial (RCT) of DED; and 6) the Biomarker Laboratory can track a large number of masked samples reliably. In conclusion, our standard operating procedure for impression cytology analysis of HLA-DR expression appears to be repeatable and reproducible for use in multicenter clinical trials, providing a minimally invasive objective biomarker of inflammation of the ocular surface.

Limbal epithelial cell therapy: past, present, and future

The cornea, the clear window at the front of the eye, transmits light to the retina to enable vision. The corneal surface is renewed by stem cells located at the peripheral limbal region. These cells can be destroyed by a number of factors, including chemical burns, infections, and autoimmune diseases, which result in limbal stem cell deficiency (LSCD), a condition that can lead to blindness. Established therapy for LSCD based on ex vivo expanded limbal epithelial cells is currently at a stage of refinement. Therapy for LSCD is also rapidly evolving to include alternative cell types and clinical approaches as treatment modalities. In the present perspectives chapter, strategies to treat LSCD are discussed and advances in this important field of regenerative medicine are highlighted.

[Epidemic keratoconjunctivitis]

INTRODUCTION

Keratocnjunctivitis is corneal and conjunctival inflammation. Clinical signs involve the irritating trio: mixed hyperemia of conjunctival membranes, corneal subepthelial infiltrates and regional lymphadenopathy. The most common causes of epidemic are adenovirus, herpes virus, and rarely cytomegalovirus, which are now occurring with higher frequency as secondary infections.

OBJECTIVE

The aim of the study was to present and analyze keratoconjunctival epidemics in the region of Kragujevac from September 2008 to February 2009, as well as to analyze clinical features related to virusological findings and etiology.

METHODS

In 329 patients we performed clinical examination (biomicroscopy, fluorescent test, corneal sensitivity test), collecting standard specimen of the conjuctiva and cornea, made serological examination, and sent the specimens to the Virusology Institute "Torlak" in Belgrade for the confirmation of epidemic etiology. The patients were treated with local and symptomatological therapy. The epidemic was eradicated in cooperation with a regional referent institution. All outpatients activities were ceased, while hospital hygienic, sanitary, intra-, extra-hospital and therapeutic procedures were undertaken.

RESULTS

The distribution of 329 patients by gender was equivalent. Most patients were aged from 27 to 34 years (25%) of working population. The distribution of patients by clinical features showed the predominance of follicular hyperplasy (93.62%). The distribution according to the time of the first symptoms onset showed the frequency of 50% of corneal infiltrate in the second week. The period elapsed from the diagnosis to cure was three weeks in 50% of patients. Serological tests confirmed the mixed distribution of the cause.

CONCLUSION

Based on the authors' experience, in order to eradicate epidemics as fast as possible and achieve efficient treatment, it is recommended that the epidemic should be reported, guidelines of referent institutions be obeyed, all of which diminishes the recognizable professional risk and decreases mistakes.

Fluorescein punctate staining traced to superficial corneal epithelial cells by impression cytology and confocal microscopy

PURPOSE

The basis of fluorescein-associated superficial punctate staining in dry eyes is controversial. Prior explanations include fluorescein pooling in surface erosive defects, intercellular trapping of fluorescein, and intracellular staining in dead cells. In this study, the hypothesis that punctate erosions are individual cells with enhanced fluorescence was tested.

METHODS

Ten impression cytology membrane materials were compared, to optimize cellular yield in buccal mucosa and cornea. Clinicocytologic correlation of punctate fluorescent spots was performed in four dry eye patients. Individual punctate spots were localized by fiducial marks in photographs, before and after removal with impression membranes, and were traced in fluorescence microscopy and cytologic staining. Two-way contingency table analysis was used to determine the correlation of punctate spots with cells removed by the membrane. Clinicopathologic correlation of punctate spots was performed in 10 corneas removed in dry eye patients by transplantation for concurrent diseases. Punctate fluorescence was tracked in specimens by fiducial marks and epifluorescence. The distribution of fluorescent spots in specific cell layers of the cornea was determined by confocal microscopy.

RESULTS

Cellular yield was greatest with impressions from polytetrafluoroethylene (PTFE [Teflon]; BioPore; Millipore, Billerica, MA) membrane compared with its closest rival (P = 0.019). Punctate fluorescent spots, most of which disappeared after impression cytology (71%), correlated with cells on the membranes (P = 0.009). The punctate spots were more frequent in the superficial cell layers of the cornea (80%) compared with the deepest two layers (0%) (P < 0.00049).

CONCLUSIONS

Punctate epithelial erosions correspond to enhanced fluorescence in epithelial cells predominantly in superficial layers of the cornea and would be more aptly named fluorescent epithelial cells (FLECs).

Successful clinical implementation of corneal epithelial stem cell therapy for treatment of unilateral limbal stem cell deficiency

The corneal epithelium is maintained by a population of stem cells known as limbal stem cells (LSCs) due to their location in the basal layer of the outer border of the cornea known as the limbus. Treatment of limbal stem cell deficiency (LSCD) has been achieved with transplantation of ex vivo expanded LSCs taken from a small biopsy of limbus. This is a relatively new technique, and as such, specific national or international guidance has yet to be established. Because of the lack of such specific guidance, our group has sought to minimize any risk to the patient by adopting certain modifications to the research methodologies in use at present. These include the replacement of all non-human animal products from the culture system and the production of all reagents and cultures under Good Manufacturing Practice conditions. In addition, for the first time, a strictly defined uniform group of patients with total unilateral LSCD and no other significant ocular conditions has been used to allow the success or failure of treating LSCD to be attributable directly to the proposed stem cell therapy. A prospectively designed study with strict inclusion and exclusion criteria was used to enroll patients from our database of patients with unilateral LSCD. Eight eyes of eight consecutive patients with unilateral total LSCD treated with ex vivo expanded autologous LSC transplant on human amniotic membrane (HAM) with a mean follow-up of 19 (RANGE) months were included in the study. Postoperatively, satisfactory ocular surface reconstruction with a stable corneal epithelium was obtained in all eyes (100%). At last examination, best corrected visual acuity improved in five eyes and remained unchanged in three eyes. Vision impairment and pain scores improved in all patients (p < .05). This study demonstrates that transplantation of autologous limbal epithelial stem cells cultured on HAM without the use of non-human animal cells or products is a safe and effective method of reconstructing the corneal surface and restoring useful vision in patients with unilateral total LSCD.

Difficulties imaging herpes simplex keratitis with fluorescein isothiocynate-labeled anti-HSV-1 antibodies in an ex vivo model

AIM

The aim of this study was to attempt to visualize herpes simplex keratitis in an ex vivo model using currently available ophthalmological equipment and anti-herpes simplex virus 1 (HSV-1) fluorescein isothiocynate-labeled antibody.

METHODS

Sixteen donor human corneas were included in this study. Eight corneas were infected with HSV-1, whereas 8 remained uninfected. Abrasions were made on 2 infected and 2 uninfected corneas to assess a possible nonspecific absorption of antibodies in the sites of corneal epithelial defects. Corneas were examined before and after antibody application using a slit lamp, the fluorescein enhancing filter settings of fundus camera, and Confoscan 3. All corneas were further imaged using multiphoton laser confocal microscopy.

RESULTS

Before anti-HSV-1 antibody application, no fluorescence was detected in donor corneas with the blue light of the slit lamp and fundus camera at fluorescein enhancing filter settings. Examination with the fundus camera after antibody application detected increased background fluorescence in all the corneas with more highlighted areas of epithelial defects in abraded infected and uninfected corneas. Confoscan 3 did not show a significant difference between the appearances of HSV-1-infected and control corneas with and without application of the antibody. However, specific staining was confirmed by multiphoton laser confocal microscopy in all infected corneas.

CONCLUSION

Further refinement of currently available ophthalmological tools is required to aid in vivo visualization of herpes simplex keratitis using fluorescein isothiocynate-labeled antibodies.

Role of impression cytology in diagnosis of ocular surface neoplasia

PURPOSE

To compare the accuracy of impression cytology in the diagnosis of ocular surface neoplasia with tissue histology.

METHODS

We reviewed the histories of patients diagnosed with ocular surface neoplasia at the Chiang Mai University Hospital. All patients underwent both impression cytology and tissue biopsy. We compared the results of both methods.

RESULTS

There were 55 patients (33 men and 22 women), with an age range of 12-99 years (mean, 51 years). Twenty patients had lesions in the right eye and 35 had them in the left eye. The most common histologic report was conjunctival-corneal intraepithelial neoplasia (38.2%), followed by squamous cell carcinoma (34.5%), nonneoplastic changes of squamous epithelia (10.9%), squamous papilloma (7.3%), conjunctival nevi (7.3%), and malignant melanoma (1.8%). Compared with histologic findings, the positive and negative predictive accuracy of impression cytology was 97.4% and 52.9%, respectively. For squamous neoplasms, squamous cell carcinoma had the highest correlation with histology. The presence of dysplastic cells suggested malignancy.

CONCLUSIONS

This study shows that impression cytology might have a promising role in diagnosing ocular surface neoplasia for its high positive predictive accuracy compared with tissue histology. However, a fair negative predictive accuracy indicates that impression cytology is a valuable screening technique, but it is not a "gold standard."

Infectious keratitis

PURPOSE OF REVIEW

Infectious keratitis is a medical emergency. Improper management can lead to marked loss of vision. This review identifies recent trends in the study of infectious keratitis.

RECENT FINDINGS

A multicountry outbreak of Fusarium keratitis emphasizes that contact lens wear is a major risk factor for infectious keratitis. Acanthamoeba and fungal keratitis are the most expensive forms of infectious keratitis to treat. Noninvasive methods and molecular techniques have improved diagnosis of infectious keratitis. Fortified topical antibiotics and fluoroquinolones are still the mainstay of bacterial keratitis therapy. Voriconazole and new routes of administration of conventional antifungals appear promising for fungal keratitis. Antivirals and amelioration of host inflammatory response are promising for viral keratitis; the host response is also crucial in pathogenesis of Pseudomonas aeruginosa keratitis. Trauma-induced bacterial and fungal keratitis and contact lens-associated keratitis are preventable entities.

SUMMARY

Improved modalities of diagnosis and treatment have improved the outcome of infectious keratitis, but therapy of acanthamoebal, fungal and P. aeruginosa keratitis is still a challenge. Effective strategies must neutralize potential risk factors and counter host response overactivity without impairing killing of infecting microorganisms. Trauma-induced bacterial and fungal keratitis can be prevented.

Amniotic membrane transplantation combined with antiviral and steroid therapy for herpes necrotizing stromal keratitis

PURPOSE

To evaluate therapeutic effect of multilayer amniotic membrane transplantation (AMT) in conjunction with antiviral and corticosteroid therapy on herpes necrotizing stromal keratitis.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Fifteen patients (15 eyes) with herpes necrotizing stromal keratitis, persistent corneal inflammation, and impending ulcer, despite topical and systemic antiviral treatment for over 2 weeks.

METHODS

Multilayer AMT was performed in the 15 eyes. Antiviral medications and appropriate corticosteroids were administered after surgery. Remodeling of amniotic membrane (AM) and growth of epithelial cells were detected by confocal microscopy.

MAIN OUTCOME MEASURES

Visual acuity and corneal status (ulceration, edema, and opacification).

RESULTS

Follow-up ranged from 7 to 13 months (mean +/- standard deviation, 8.9+/-1.8). Visual acuity improved by > or =2 lines in 14 eyes. Central corneal ulcers healed completely at 2.0+/-0.6 weeks, and paracentral ulcers at 2.1+/-0.6 weeks (t = 0.314, P = 0.759). Corneal stromal thickness was restored in eyes with central ulcers at 2.4+/-1.2 weeks and in those with paracentral ulcers at 2.6+/-0.7 weeks (t = 0.425, P = 0.678). Superficial epithelial cells, together with small basal epithelial cells, gradually migrated to the surface of AM on postoperative weeks 1 to 3. There were corneal nebulae in 11 eyes, corneal maculae in 3 eyes, and a corneal leukoma in 1 eye at the end of follow-up. No recrudescence occurred in any eye.

CONCLUSION

Multilayer AMT combined with antiviral and corticosteroid therapy appears effective in treating herpes necrotizing stromal keratitis. It provides patients with marked scars and visual impairment an opportunity for subsequent keratoplasty by arresting the inflammatory response and reducing the graft bed diameter.

[Ocular surface investigations in dry eye]

Dry eye is a complex clinicopathological entity involving tear film, lacrimal glands, eyelids, and a wide spectrum of ocular surface cells, including epithelial, inflammatory, immune, and goblet cells. From the tightly regulated lacrimal film functions and structure, a large variety of investigations have been developed, including tear meniscus measurements, fluorophotometry, meibometry, interference pattern analysis, evaporation rate, tear osmolarity, and thermography. Dry eye conditions also interfere with the ocular surface, causing corneal irregularities that may be explored using the techniques of videokeratography and in vivo confocal microscopy, or optical impairment, as confirmed by aberrometry. At the level of ocular surface cells, impression cytology remains a standard for assessing cell alterations. It has greatly benefited from new confocal microscopy, molecular biology, and flow cytometry techniques. Biological assessment of tear proteins or other mediators is also useful. Major limits should be acknowledged, however, such as technical issues in tear film collection, especially in dry eyes, and the lack of standardization of most measurements. Tear osmolarity, electrophoresis, and dosage of normal tear proteins, such as lysozyme or lactoferrin, remain the most useful tests. Finally, some extraocular explorations such as accessory gland biopsy or serum antinuclear antibody dosage may be useful for assessing the diagnosis of Sjögren's syndrome.

Predictive value of exfoliative cytology in pigmented conjunctival lesions

PURPOSE

Pigmented lesions of the conjunctiva are often difficult to classify clinically. Exfoliative cytology may be helpful, but reliable data regarding the sensitivity and specificity of this test are currently lacking. We determined the value of exfoliative cytology with regard to pigmented conjunctival lesions.

METHODS

A total of 294 smears from 182 patients were screened for malignancy within 6 months of exfoliative cytology. Smears were classified according to the following categories: grade 0 = insufficient material for diagnosis; grade 1 = normal conjunctival cells; grade 2 = melanocytes with mild atypia; grade 3 = melanocytes with moderate atypia, and grade 4 = melanocytes with severe atypia.

RESULTS

The sensitivity, specificity, positive predictive value and negative predictive value of exfoliative cytology were 85%, 78%, 59% and 93%, respectively.

CONCLUSION

Exfoliative cytology is a fast, easy and non-invasive technique that may be used in the evaluation of patients with a pigmented conjunctival lesion.

Evaluation of herpes simplex detection in corneal scrapings by three molecular methods

Herpes simplex virus (HSV)-1 keratitis (HSK) is a sight-threatening ocular infection with worldwide occurrence. A prompt laboratory diagnosis is often very useful. The purpose of this study was to evaluate molecular methods as rapid diagnostic tools compared with cell culture of HSK. Corneal scrapings from patients with clinically suspected HSK were tested by direct immunofluorescence assay (IFA) for HSV-1 antigen and by polymerase chain reaction (PCR) for HSV-1 DNA, and an attempt for viral isolation was performed on Vero cell line culture. Positive samples by cell culture were 20.8%, whereas PCR was positive in 29.2%, and IFA was positive in 33.3%. IFA had better sensitivity (80%) and negative predictive value (81.8%) than PCR (70% and 76.9%, respectively); however, PCR had better specificity (71.4%) and positive predictive value (63.6%). This indicates that a combination of cell culture, IFA and PCR constitutes the best set of tools for diagnosis of clinically suspected cases of HSK. Documented infection can be further assessed by cell-culture technique or PCR depending laboratory availability.

Impression cytology of the ocular surface

Impression cytology refers to the application of a cellulose acetate filter to the ocular surface to remove the superficial layers of the ocular surface epithelium. These cells can then be subjected to histological, immunohistological, or molecular analysis. Proper technique is essential as the number of cells sampled can vary considerably. Generally two to three layers of cells are removed in one application but deeper cells can be accessed by repeat application over the same site. Applications for impression cytology include diagnosing a wide range of ocular surface disorders, documenting sequential changes in the conjunctival and corneal surface over time, staging conjunctival squamous metaplasia, and monitoring effects of treatment. It is also a useful investigational tool for analysing ocular surface disease with immunostaining and DNA analysis. It is non-invasive, relatively easy to perform, and yields reliable information about the area sampled with minimal discomfort to the patient. Major ophthalmic centres should develop and introduce this technique into routine clinical practice. This is best achieved with a team approach including the ophthalmologist, pathologist, microbiologist, and the immunologist.

Subconjunctival cyst-like formations following impression cytology

PURPOSE

To report a case of an unusual adverse event subsequent to undertaking Conjunctival Impression Cytology (CIC).

METHODS

CIC was undertaken on a 54-year-old healthy Caucasian female, using a 10 mm Millipore membrane on the bulbar conjunctiva. Prior to the CIC procedure, two drops of topical proparacaine (Alcaine were instilled and following the procedure two drops of artificial tears (GenTeal were administered.

RESULTS

The subject reported excessive bulbar conjunctival hyperaemia in the left eye 5 min postprocedure, with no marked pain or discomfort. Slitlamp biomicroscopic evaluation revealed several "bubbles" or cystic formations trapped underneath the conjunctival tissue, in association with moderate to severe bulbar conjunctival redness. These cysts began to regress fairly rapidly and completely disappeared within 1h.

CONCLUSION

CIC is a useful tool for studying the ocular surface; however, care should be taken while performing this mildly invasive procedure. This is the first report of bubble formation in the conjunctiva following CIC. Subjects should be advised about the short term redness and discomfort that could occur following CIC.

Impression cytology of the ocular surface: a review

PURPOSE

To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology.

METHODS

A comprehensive review of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken.

RESULTS

A wide range of processing methods have been adapted to the technique of impression cytology (from conjunctiva, cornea or limbus): regular light microscopy with different stainings, transmission and scanning electron microscopy, immunofluorescence, immunocytochemistry, polymerase chain reaction analysis, immunoblotting analyses, or flow cytometry. At present, it is widely used as a non-invasive alternative to the full-thickness biopsy for the obtention of epithelial cells from the ocular surface.

CONCLUSIONS

Impression cytology represents a non- or minimally invasive biopsy of the ocular surface epithelium with no side effects or contraindications. It has demonstrated to be a useful diagnostic aid for a wide variety of processes involving the ocular surface. In addition, and mainly during the last decade, its use as a research tool has experienced an enormous growth and has greatly contributed to the understanding of ocular surface pathology.

Comparison of autologous serum eye drops with conventional therapy in a randomised controlled crossover trial for ocular surface disease

AIMS

To evaluate the efficacy of 50% autologous serum drops against conventional treatment in ocular surface disorders refractory to normal treatments in a prospective randomised crossover trial.

METHOD

Patients fulfilling ophthalmological and haematological entry criteria were randomised to either 3 months of autologous serum 50% followed by 3 months of their conventional treatment, or 3 months of conventional treatment, followed by 3 months of autologous serum. Clinical assessments, including Schirmer's test, rose Bengal, and fluorescein staining, were carried out on entry and at monthly intervals. Impression cytology was performed at entry, 3 and 6 months. Grading was carried out on degrees of squamous metaplasia and goblet cell density. Subjective comfort was recorded daily using the "faces" scale. These categorical scores were converted to linear measurement using Rasch analysis. Statistical analysis was carried out using Wilcoxon's signed rank test and ANOVA.

RESULTS

16 patients were recruited with 31 eyes studied. The ocular surface diseases chiefly included Sjögren's syndrome (n = 6) and keratoconjunctivitis sicca (n = 5). Impression cytology available in 25 of 31 eyes showed significant improvement on serum treatment, p<0.02. Rasch weighted faces scores were statistically significantly better with serum, p<0.01.

CONCLUSION

The results of this randomised study provide further evidence of the beneficial effects of autologous serum in severe ocular surface disorders. For most of these patients, autologous serum was superior to conventional treatment for improving ocular surface health and subjective comfort.

Flow cytometry in conjunctival impression cytology: a new tool for exploring ocular surface pathologies

Flow cytometry (FCM) is a widely used technique, not only in immunology and hematology but also in many other domains and new applications have been developed in ophthalmology, for investigating ocular surface biology and pathophysiology. Apoptosis, proteins specific of cell lineage, expression of activation or immune-related markers, proinflammatory cytokine production, multi-drug resistance and oxidative stress are some examples of possible pathways that may be explored directly using ocular surface cells removed with the non-invasive technique of impression cytology, by means of flow cytometry. Conjunctival cells are thus collected by impression cytology on a filter, fixed in paraformaldehyde and dissociated by agitation before immunostaining and FCM processing. Important observations have been made concerning Sjögren's syndrome, ocular allergy and antiglaucoma eye drop toxicity. Studies performed on impression cytology with FCM techniques confirmed inflammatory and apoptotic patterns in a large number of patients with keratoconjunctivitis sicca or receiving long-term treatments with antiglaucoma drugs, even though they did not present any clinical signs of inflammation. FCM may now be used for large multicenter clinical trials and has already contributed to a better understanding of ocular surface pathophysiology, the monitoring of new immunomodulating drugs and knowledge concerning topical drugs, as regards both efficacy and safety.

Diagnosis of herpes simplex virus-1 keratitis using Giemsa stain, immunofluorescence assay, and polymerase chain reaction assay on corneal scrapings

AIMS

To evaluate three tests used routinely for the diagnosis of herpes simplex virus (HSV) keratitis.

METHODS

Corneal scrapings from 28 patients with clinically typical dendritic corneal ulcer suggestive of HSV keratitis, and 30 patients with clinically non-viral corneal ulcers, were tested by (i) Giemsa stain for multinucleated giant cells, (ii) immunofluorescence assay (IFA) for HSV-1 antigen, and (iii) polymerase chain reaction (PCR) for HSV-1 DNA, by investigators masked to clinical diagnosis. The control subjects were also investigated by smears and cultures for bacteria, fungus, and Acanthamoeba.

RESULTS

The specificity and positive predictive values of all three tests for the diagnosis of HSV keratitis were between 95-100%. The sensitivity of IFA and PCR was 78.6% and 81.2%, respectively, and the difference was not significant; however, their sensitivity and negative predictive value were significantly higher than Giemsa stain.

CONCLUSIONS

While a combination of IFA and PCR constitute the choice of tests in clinically suspected cases of HSV keratitis, multinucleated giant cells in Giemsa stain can pre-empt testing by IFA and PCR in otherwise atypical cases of HSV keratitis.

Ocular surface impression cytology

Impression cytology, either using cellulose acetate strips or the Biopore membrane device, is a simple, noninvasive technique that aids in the diagnosis of several disorders of the ocular surface. These disorders include ocular surface squamous neoplasia, dry eye syndrome, limbal stem-cell deficiency, specific viral infections, vitamin A deficiency, allergic disorders, conjunctival melanosis, and malignant melanoma. Another advantage is the preservation of limbal stem cells, which occur in the basal layer of the limbal epithelium and are responsible for renewal of the corneal epithelium. The Biopore membrane device is particularly user friendly, with little expertise required and adequate specimens obtained in a very high percentage of cases. The most common applications in diagnostic ocular pathology are:(i) primary diagnosis and follow-up of ocular surface squamous neoplasia, including after therapy with topical mitomycin C. The sensitivity is high (78-87%); and (ii) dry eye syndrome where squamous metaplasia and/ or hyperkeratosis are noted. Certain limitations of the technique for diagnosis of squamous neoplasia include the fact that dysplasias are often keratinizing and may yield very few or even no dysplastic cells with impression cytology. Secondly, no definite cytologic criteria reliably distinguish invasive SCC of ocular surface from in situ disease. Other applications include the rapid specific diagnosis of ocular surface infections with herpes simplex, adeno-, and varicella zoster viruses. Impression cytology samples may also be used to obtain mRNA, cells for phenotyping by flow cytometry, and proteins for Western blotting for research studies.

Ocular Surface Squamous Neoplasia

Even though ocular surface squamous neoplasia (OSSN) has been recognized for well over a century, the past decade has witnessed advances that have helped rewrite many of the paradigms for the diagnosis and management of these lesions. OSSN occurs predominantly in the elderly for whom they are the third most common oculoorbital tumors after melanoma and lymphoma. In addition to advanced age and male sex, other major risk factors linked to its pathogenesis are ultraviolet light, cigarette smoking, and the human papilloma virus. Although the latter has been linked to OSSN for nearly 4 decades, its identification and role in the pathogenesis of these tumors has been elucidated recently and is addressed in detail in this review. Newer techniques of impression cytology represent a noninvasive and reliable method of diagnosing OSSN and monitoring treated cases. The efficacy of chemotherapeutic agents such as mitomycin C and 5-fluorouracil have been proven in the recent past, making them a clear alternative to the time-tested treatment of surgical excision and cryotherapy. Early reports on the efficacy of topical Iterferon alpha 2b indicate significant promise in providing another alternative for the treatment of some of these neoplasms. These advances thus represent a minimally invasive and highly successful approach to the diagnosis and treatment of OSSN.

Analysis of limbal stem cell deficiency by corneal impression cytology

PURPOSE

The impaired function of corneal epithelial stem cells, located in the limbus, is responsible for corneal surface damage and is clinically characterized by recurrent epithelial defects, conjunctivalization, neovascularization, and corneal opacity. The aim of this study was to investigate corneal limbal stem cell deficiency (LSCD) by means of the impression cytology (IC) technique, using antibodies against cytokeratin 19 (CK19) and cytokeratin 3 (CK3), and to evaluate the diagnostic potential of this approach.

METHODS

Over a 3-year period (October 1998-June 2001), we collected 113 pairs of IC samples from the eyes of 85 patients with a range of ocular surface diseases and performed an immunocytochemical analysis of CK19 and CK3. Samples with more than 50% cellularity were considered suitable for diagnostic purposes, while samples with less than 50% cellularity were considered with caution. CK19-positive cells in corneal IC were considered an expression of LSCD. We arbitrarily scored LSCD as mild (<25% of CK19-positive cells), moderate (25-50%), and severe (>50%).

RESULTS

One hundred thirteen pairs of IC specimens were obtained from 85 patients; 32 patients (37.6%) had alkaline burns, 18 (21.2%) had other chemical or physical corneal injuries, 13 (15.3%) had complications from wearing contact lenses, 8 (9.4%) had severe microbial keratitis, and 14 (16.5%) had suspicious limbal deficit due to other causes. Nine patients underwent bilateral sampling and 12 had to be resampled. Thirteen pairs of IC specimens were obtained during the follow-up of 8 patients who had undergone limbal stem cell transplantation. In 3 of these patients, IC confirmed reversion to corneal immunophenotype (CK3+/CK19-), whereas in 4, residual limbal damage was still evident; 1 patient relapsed. In the remaining 100 pairs of impressions, we found 77 cases of LSCD, whereas in 16 pairs, we did not find LSCD. Seven pairs were defined as "not valuable" because of the poor quality of both CK samples. Diffuse LSCD, moderate or severe in degree, was found in 26 of 32 patients (81.2%) with alkali burns, whereas mild diffuse LSCD or sectoral LSCD was found in 13 of 18 patients (72.2%) with other chemical-physical injuries, in 10 of 13 patients (76.9%) wearing contact lenses, in 7 of 8 patients (87.5%) with severe microbial keratitis, and in 12 of 14 patients (85.7%) with other corneal pathologies. The quality of impressions was assessed in 77 cases and found to be good or discrete for both CKs in 32 cases (41.5%) and poor in 45 (58.5%): in 46.7% of these cases, the IC was poor only for CK19 and in 45.4% only for CK3.

CONCLUSIONS

Immunocytochemistry for seeking out CK19- and CK3-positive cells on corneal IC is a simple and practical method to investigate LSCD. We believe that this technique could have an important role in evaluating patients undergoing therapeutic penetrating keratoplasty to select those who would benefit from limbal stem cell transplantation. Since sampling has been shown to be a critical point, we believe that any improvement in this area will also help to improve the methodology and will contribute to its wider utilization.

Comparison of an immortalized human corneal epithelial cell line with Vero cells in the isolation of Herpes simplex virus-1 for the laboratory diagnosis of Herpes simplex keratitis

BACKGROUND

Herpes simplex keratitis (HSK) is a sight threatening ocular infection often requiring a specific and prompt laboratory diagnosis. Isolation of Herpes simplex virus (HSV-1) in culture provides the most reliable and specific method and is considered as the "Gold Standard" in the laboratory diagnosis of HSK in spite of its low sensitivity. Using "cell lines of corneal origin" for virus isolation may be beneficial under such circumstances, since these cells have been shown to be excellent substrates for the growth of HSV-1 isolated from the cornea. We report a comparative study of a novel human corneal epithelial cell line (HCE) and the Vero cell line in the isolation of HSV-1 from corneal scrapings employing a shell vial assay.

METHODS

Corneal scrapings were obtained from 17 patients with a clinical diagnosis of HSK. All the cases were confirmed by virological investigations (PCR and viral antigen detection positive, n = 15, PCR positive, n = 1, Viral antigen positive, n = 1). Scrapings obtained from 10 patients with infectious keratitis of non-viral origin were included as controls. All the scrapings were simultaneously inoculated into shell vials of HCE and Vero cells. Cultures were terminated at 24 h post-infection. Isolation of HSV-1 was confirmed using an indirect immunofluorescence/ immunoperoxidase assay.

RESULTS

Virus could be isolated using both or either of the cell lines in 10/17 (58.82%) patients with HSK. HSV-1 was isolated from 10/17 (58.82%) and 4/17(23.52%) specimens in HCE and Vero cells, respectively (P = 0.036). None of the controls yielded HSV-1. While all the 10 (100%) strains were isolated in HCE, Vero yielded only 4/10 (40%) strains in the shell vial culture (P = 0.014).

CONCLUSIONS

HCE showed a statistically significant difference in the virus isolation rate with respect to Vero cells. HCE may be an excellent alternative cell line for the isolation of HSV-1, especially from corneal scrapings, for the laboratory diagnosis of HSK.

Comparison of the sensitivity of a 24 h-shell vial assay, and conventional tube culture, in the isolation of Herpes simplex virus - 1 from corneal scrapings

BACKGROUND: Herpes simplex keratitis is a sight threatening ocular infection. A rapid and specific diagnosis is essential for the institution of specific antiviral therapy and to avoid complications that can arise from misdiagnosis and inappropriate treatment. Though a variety of techniques are available, isolation of Herpes simplex virus 1 (HSV-1) in culture provides the most reliable and specific method, and is considered as the gold standard in laboratory diagnosis of herpes simplex keratitis. We report a comparative study of the sensitivity of a 24 h-shell vial assay and conventional tube culture in the isolation of HSV-1 from corneal scrapings. METHODS: A total of 74 corneal scrapings obtained from 74 patients with a clinical suspicion of herpes simplex keratitis submitted for the isolation of HSV-1, were simultaneously inoculated into shell vial and tube cultures employing the vero cell line. Shell vial and tube cultures were terminated at 24 h and fifth day respectively. Isolation of HSV-1 was confirmed employing an indirect immunofluorescence assay. RESULTS: HSV-1 was isolated from 24/74 (32.4%) specimens employing both the methods. Sensitivity of both the techniques were found to be similar (20/24, 83.3%) (P = 1.0). CONCLUSION: A 24 h-shell vial assay is a rapid alternative technique in comparison to the time consuming conventional tube cultures for the isolation of HSV-1, especially from corneal scrapings for the laboratory diagnosis of herpes simplex keratitis.

Collection of corneal impression cytology directly on a sterile glass slide for the detection of viral antigen: an inexpensive and simple technique for the diagnosis of HSV epithelial keratitis - a pilot study

BACKGROUND

Herpes simplex keratitis (HSK) is a sight threatening ocular infection and occurs worldwide. A prompt laboratory diagnosis is often very useful. Conventional virology techniques are often expensive and time consuming. We describe here a highly economical, simple, rapid and sensitive technique for the collection of impression cytology, for the laboratory diagnosis of HSK.

METHODS

Fifteen patients with a clinical diagnosis of HSK (either dendritic or geographic ulcers) and five patients with other corneal infections (Mycotic keratitis, n = 3, Bacterial keratitis, n = 2) were included in the study. Corneal impression cytology specimens were collected using a sterile glass slide with polished edges instead of a membrane, by pressing the surface of one end of the slide firmly, but gently on the corneal lesion. Additionally, corneal scrapings were collected following the impression cytology procedure. Impression cytology and corneal scrapings were stained by an immunoperoxidase or immunofluorescence assay for the detection of HSV-1 antigen using a polyclonal antibody to HSV-1. Corneal scrapings were processed for viral cultures by employing a shell vial assay.

RESULTS

This simple technique allowed the collection of adequate corneal epithelial cells for the detection of HSV-1 antigen in a majority of the patients. HSV-1 antigen was detected in 12/15 (80%) cases while virus was isolated from 5/15 (33.3%) patients with HSK. All the patients with a clinical diagnosis of HSK (n = 15) were confirmed by virological investigations (viral antigen detection and/or viral cultures). HSV-1 antigen was detected in the impression cytology smears and corneal scrapings in 11/15 (73.3%) and 12/15 (80%) of the patients, respectively (P = 1.00). None of the patients in the control group were positive for viral antigen or virus isolation. Minimal background staining was seen in impression cytology smears, while there was some background staining in corneal scrapings stained by the immunoassays.

CONCLUSIONS

Collection of impression cytology on a sterile glass slide is a simple, rapid and inexpensive technique for the diagnosis of HSK. Immunological techniques applied on such smears provide virological results within 2-5 hours. This technique could be modified for use in the diagnosis of other external eye diseases, which needs further evaluation.

Impression cytology following mitomycin C therapy for ocular surface squamous neoplasia

BACKGROUND/AIMS

Topical mitomycin C (MMC) therapy has been used for treatment of ocular surface squamous neoplasia (OSSN) since 1994. Relatively few studies have reported the cellular changes in ocular surface following MMC.

METHODS

Impression cytology was studied in four patients with ocular surface squamous neoplasia, either primary or recurrence after previous excisional biopsy. The authors studied samples obtained using Millipore filters at intervals between 4 and 17 weeks after commencement of MMC, and compared them with pretreatment cytology.

RESULTS

MMC induced changes of cytomegaly, cytoplasmic vacuolation, nucleomegaly with nuclear wrinkling, and binucleation or multinucleation were seen in some cells in all samples. However, nuclear/cytoplasmic (N/C) ratio in these enlarged cells was normal. These changes mimicked those seen following radiation therapy in uterine cervix. Changes of increased nuclear and cell size with increased N/C ratio were seen in some dysplastic cells. The predominant form of cell death was apoptosis with fewer cells showing necrosis.

CONCLUSIONS

MMC appears to produce cell death in OSSN by apoptosis and necrosis. Cellular changes related to MMC mimic those caused by radiation-cytomegaly, nucleomegaly, and vacuolation. MMC related changes may persist in ocular surface epithelium for at least 8 months following MMC therapy.

Reliability of impression cytology for the diagnosis of ocular surface squamous neoplasia employing the Biopore membrane

AIM

To evaluate the accuracy of impression cytology employing a Biopore membrane device in the diagnosis of ocular surface squamous neoplasia (OSSN).

METHODS

The histology of patients undergoing excision biopsy for the suspected diagnosis of OSSN over a 20 month period was compared with the reported cytology of impression cytology specimens obtained preoperatively using the Biopore membrane device.

RESULTS

25 excision biopsies were performed for suspected OSSN. There was accurate correlation in 20 out of the 25 cases (80%). In three cases (12%), there was poor correlation in that only a few dysplastic cells and hyperkeratosis were noted on cytology, whereas histology showed keratinising dysplasia in two cases and a moderately differentiated keratinising squamous cell carcinoma in the third. There were two cases (8%) of non-correlation--one keratinising dysplasia on histology, but anucleate keratin, squamous metaplasia, and rare atypical cells on cytology, and another case with very mild focal dysplasia on histology but squamous metaplasia on cytology. Review of the cytology showed that dysplastic cells were either rare or absent from the cytology specimens in these two cases; it was felt that these represented sampling problems rather than true false negatives. There were no false positives on cytology. Final diagnosis on histology was squamous cell carcinoma in one; carcinoma in situ in two; keratinising dysplasia in 15, non-keratinising dysplasia in seven.

CONCLUSION

Impression cytology employing the Biopore membrane accurately predicts the histological diagnosis of OSSN. The presence of hyperkeratosis, inflammatory cells with only a few dysplastic cells, may indicate high grade keratinising dysplasia or squamous cell carcinoma. The method is both rapid and easy to perform in routine clinical practice. These findings suggest that there may be a role for its use in the initial assessment and follow up of patients with suspected OSSN.