Bengal Staining Research Articles

Treatment of Superior Limbic Keratoconjunctivitis With a Large-Diameter Contact Lens and Botulium Toxin A Treatment of superior limbic keratoconjunctivitis with a large-diameter contact lens and botulium toxin a.

To evaluate the effect of a large-diameter (16-20 mm) hydrogel contact lens (CL) or an injection of Botulinum Toxin A to Riolan muscle for the treatment of superior limbic keratoconjunctivitis (SLK). Eight eyes from 8 patients were fitted with large-diameter CL for 7 days. The clinical improvement and changes of fluorescein and rose bengal staining were examined on the day of diagnosis and 3, 7, 14, and 30 days after the CL was fitted. Three eyes showing symptoms of recurrence of SLK within 1 month after removal of the CL and 2 eyes with complications related to CL were treated with an injection of Botulinum Toxin A to pretarsal orbicularis muscle, Riolan. The changes of symptoms and vital stains were also evaluated on day 7 and 1, 2, 3, and 6 months after the injection. The mean age was 48 +/- 13.5 years, and the group consisted of 6 females and 2 males. Dry eye syndrome and horizontal conjunctival corrugation were found in all 8 patients, superior conjunctivochalasis in 5 patients, and floppy eyelid syndrome in 2 patients. Complete resolution after more than 1 month with CL only was seen in 3 eyes (37.5%). Clinical symptoms improved in 4.62 days and vital staining in 10.75 days after fitting of the CL. Superficial punctuate keratopathy related to CL occurred in 3 eyes (37.5%). Five eyes (62.5%) that were treated with botulinum showed distinct improvement within 7 days after the injection, and the effect was maintained for 2-7 months. The fitting of large-diameter CL can be considered for the treatment of acute severe symptoms of SLK for a short time. An injection of Botulinum toxin to the Riolan muscle can effectively and rapidly resolve the symptoms associated with SLK, and its effect of maintenance was a mean of 4 months.

Efficacy of topical cyclosporine A in the treatment of severe trachomatous dry eye

The purpose of this study was to evaluate the efficacy of topical cyclosporine A (CsA) treatment in patients with severe trachomatous dry eye. Sixty-four severe trachomatous dry eye patients who had undergone Schirmer testing with topical anaesthetic measured 5 mm or less and a tear film break-up time (TFBUT) of 5 s or less were included in the study. Thirty-two patients were treated with CsA 0.05% ophthalmic emulsion twice daily and concomitant five times daily non-preserved artificial tear, and the other 32 patients who were designated as the control group received vehicle emulsion twice daily and non-preserved artificial tear five times daily. Pretreatment and post-treatment evaluations included subjective assessment of the patients (total symptoms scores and ocular surface disease index [OSDI] scores), Schirmer testing with topical anaesthesia, TFBUT, rose Bengal and fluorescein staining scores, conjunctival impression cytological scoring and goblet cell counting. Following 6 months of CsA treatment, the differences between the pretreatment and post-treatment test results including total symptoms scores and OSDI scores, the rose Bengal and fluorescein staining scores, TFBUT values, and the Schirmer testing measurements were found to be statistically significant. Impression cytology also showed improvement of squamous metaplasia in 26 patients (81.25%) and increase in goblet cell density in 23 patients (71.88%). Topical CsA was effective in the treatment of severe trachomatous dry eye, yielding improvements in both objective and subjective measurements with a safety profile.

Evaluation of the Effect of Changing Concentration and pH on The Activity of Rose Bengal Antigen

The present study was conducted to prepare Rose Bengal antigen by using Rose Bengal stain 1% and brilliant green 0.5%. These antigens were prepared usingdifferent concentrations (4%, 5%, 6%, 7%, 8%, 9% and 10%) and different buffer diluents with different pH (3.0, 3.5, 3.65, 4, 4.5, 5.0) to study the effect of differentantigen concentrations and pH on the Rose Bengal test. It was observed that the best results were obtained when the concentration of the antigen was more than 7% and the pH range of 3.65 to 4.0.

Long-Term Topical Cyclosporine Treatment Improves Tear Production and Reduces Keratoconjunctivitis in Rabbits With Induced Autoimmune Dacryoadenitis

To use a rabbit model of induced autoimmune dacryoadenitis to evaluate the efficacy of topical ophthalmic cyclosporine A (CsA). Autoimmune dacryoadenitis was induced by injecting autologous peripheral blood lymphocytes, which had been activated in a mixed cell reaction with acinar cells isolated from one inferior lacrimal gland (LG), back into the donor animal's remaining inferior LG. Schirmer's test, tear breakup time, and rose Bengal staining were assessed. Animals with established disease were treated topically with either CsA or Endura twice daily for 5 months. Without treatment tear production and tear stability were abnormal for 6 months, and clear signs of ocular surface defects were evident. Severe immune cell infiltration was observed in the LG. Long-term CsA treatment increased tear production only slightly, but the severity of LG histopathology decreased noticeably. CD4(+) T-cell infiltration of the LG was decreased and infiltration by MHC class II-expressing cells was also decreased. For the Endura-treated group tear production did not improve, rose Bengal scores remained high, and histopathology showed infiltration comparable to the untreated group, but by the end of the study the tear breakup time did improve. The rabbit model of autoimmune dacryoadenitis had signs of chronic dry eye disease 6 months after induction of disease. Tear production improved slightly with CsA treatment and CD4(+) T-cell infiltration decreased significantly in the LG. This suggests that some Sjögren's patients may benefit from long-term CsA treatment.

Uso de ciclosporina 0,05% tópica no tratamento do olho seco de pacientes portadores do vírus HIV

OBJETIVO: O presente estudo comparou a eficacia do tratamento da sindrome do olho seco em pacientes infectados pelo HIV com suplementacao lacrimal (carboximetilcelulose sodica 0,5%) ou com suplementacao lacrimal associada a terapia anti-inflamatoria (carboximetilcelulose sodica 0,5% e ciclosporina 0,05%). METODOS: Vinte pacientes portadores do virus HIV provenientes do ambulatorio de Infectologia do Hospital Universitario Clementino Fraga Filho da Universidade Federal do Rio de Janeiro foram selecionados. O diagnostico de sindrome do olho seco foi baseado no questionario para olho seco (Ocular Surface Disease Index - OSDI®), teste de Schirmer I, tempo de ruptura do filme lacrimal e coloracao da superficie ocular com rosa bengala a 1%. Os pacientes foram distribuidos em dois grupos com dez pacientes (20 olhos) e acompanhados durante seis meses. O grupo I foi tratado com colirio de carboximetilcelulose sodica 0,5% e o grupo II foi tratado com a associacao de carboximetilcelulose sodica 0,5% e ciclosporina 0,05% topica. RESULTADOS: Comparando os resultados no inicio e no final do tratamento, a associacao com ciclosporina 0,05% mostrou-se superior (p < 0,05) para o teste de Schirmer I. CONCLUSAO: O presente estudo sugere que o uso de ciclosporina 0,05% topica melhora a producao lacrimal em pacientes infectados pelo HIV, apresentando um importante papel como adjuvante no tratamento do olho seco nestes pacientes.

DRY EYE SYNDROME

Objective: To determine the frequency of dry eye syndrome in adult patients. Study Design: A descriptive study. Setting:Eye Department Military Hospital Rawalpindi. Period: From June 2004 to December 2004. Patients and methods: A total of hundredpatients were randomly selected from the daily OPD at eye department, MH Rawalpindi. They were tested for the presence of dry eyesyndrome by Rose Bengal staining, Schirmer tear strip measurements and Tear film break up time. Results: A total of 67 males and 33females were recruited. Out of these 10 males and 6 females were found to be having dry eye syndrome. Mean patient age was34.3±1.3years (range 20-60 years). Conclusion: The frequency of dry eye syndrome in adult patients attending the eye clinic of MilitaryHospital Rawalpindi is 16%.

Conjunctival impression cytology and tear‐film changes in patients with familial Mediterranean fever

To evaluate the ocular surface changes and tear-film functions in patients with familial Mediterranean fever (FMF). This prospective case-control clinical study examined 35 patients with FMF (group 1) and 35 controls (group 2). All patients underwent a full ophthalmological examination. Ocular surface changes were evaluated by determining cell content of surface conjunctival epithelium using conjunctival impression cytology and tear-film functions using Schirmer-I, break-up time (BUT), corneal fluorescein and Rose Bengal tests. Subjective ocular complaints were scored with a four-point scale. Between-group results were compared. In group 1, impression cytology revealed grade 0 changes in 15 eyes, grade 1 changes in 11 eyes and grade 2 changes in nine eyes in group 1; in group 2, it revealed grade 0 changes in 27 eyes, grade 1 changes in five eyes and grade 2 changes in three eyes (p = 0.013). Mean goblet cell density was 765 +/- 45 cells/mm(2) in group 1 and 1730 +/- 100 cells/mm(2) in group 2 (P < 0.001). Mean results on the Schirmer-I test results were 17.36 +/- 3.18 mm in group 1 and 19.60 +/- 4.17 mm in group 2 (p = 0.364). Mean BUT was 8.20 +/- 1.60 seconds in group 1 and 9.93 +/- 2.33 seconds in group 2 (p = 0.001). Mean corneal fluorescein and Rose Bengal staining scores were 3.26 +/- 1.67 and 0.96 +/- 0.71 in group 1 and 1.37 +/- 0.34 and 0.40 +/- 0.49 in group 2 (p = 0.037, p = 0.005). The presence of subjective ocular complaints was more frequent in group 1 than in group 2. Despite normal tear production, the ocular surface and tear-film functions of FMF patients differ from those of healthy individuals. These changes may be related to the chronic inflammatory nature of FMF.

Conjunctival Impression Cytology, Ocular Surface, and Tear-Film Changes in Patients Treated With Systemic Isotretinoin

To evaluate the ocular surface changes and tear-film functions in patients treated with systemic isotretinoin. Fifty subjects treated with 0.8 mg/kg oral isotretinoin were enrolled in this prospective clinical trial. All patients underwent a full ophthalmoscopic examination before, during, and after treatment with isotretinoin. Ocular surface changes of the cell content of the surface conjunctival epithelium were evaluated by conjunctival impression cytology and tear-film functions using the Schirmer test, anesthetized Schirmer test, tear breakup time, and rose bengal staining. Subjective ocular complaints were scored with an Ocular Surface Disease Index questionnaire. There were no significant differences observed in average Schirmer test scores for patients before, during, or after isotretinoin treatment. Mean anesthetized Schirmer test scores and tear breakup time decreased significantly during treatment (P < 0.001). Mean impression cytology scores, Ocular Surface Disease Index scores, and rose bengal staining scores increased significantly during treatment (P < 0.05, P < 0.001 and P < 0.001, respectively). Blepharitis was seen in 36% of patients. All abnormal findings disappeared 1 month after the cessation of treatment. Conjunctival epithelial cells, tear basal secretion, and tear quality are markedly affected in patients during systemic treatment with isotretinoin (0.8 mg/kg). Ocular adverse effects of isotretinoin are generally not serious and are reversible after discontinuation.

Prevalence of and Associated Factors for Dry Eye in a Spanish Adult Population (The Salnes Eye Study)

Purpose: To estimate the prevalence of dry eye and to investigate its relationship with lifestyle and systemic factors in a general adult population in north-western Spain. Methods: A dry eye questionnaire was administered and objective tests were performed in 654 individuals [mean age (Standard deviation): 63.6 (14.4) years, range: 40–96, 37.2% males]. Subjects were considered symptomatic when one or more of the symptoms of the questionnaire were present often or all the time. Schirmer test ≤ 5 mm, tear film breakup time ≤ 10 s, rose bengal staining ≥ 3 and fluorescein staining ≥ 1 were considered indicative of signs. Dry eye was defined as the simultaneous presence of symptoms and at least one sign. A design based analysis was performed and all calculations were weighted to give unbiased estimates. Results: Dry eye prevalence was 11.0% (95%confidence interval [CI] 8.6–13.3). Dry eye was found to be more frequent in women (11.9%, 95%CI 8.8–15.1) than in men (9.0%, 95%CI 5.3–12.6), and was significantly associated with aging (p < 0.001). After controlling for age and sex, acne rosacea was the only factor associated with the disease. There were no habits or systemic factors associated with symptoms. However, autoimmune diseases, acne rosacea, and computer use were found to be independently and significantly associated with signs. Conclusions: Dry eye is a common disease in this adult European population and is more frequent in older subjects. Acne rosacea is the only factor associated with dry eye. Other factors are associated with signs but not with symptoms.

Case control study of dry eye and related ocular surface abnormalities in Ibadan, Nigeria

Tear instability is associated with symptoms of ocular discomfort and irritation. Many patients with dry eyes remain untreated due to improper diagnoses. To identify symptoms and surface abnormalities associated with dry eyes. One hundred and fifty-six eyes of 78 subjects attending the Eye Clinic of the University College Hospital Ibadan were screened for dry eyes/tear instability using rose Bengal stain (graded 0-9), tear break-up time (TBUT), Schirmer's 1 tests, tear meniscus height and a standardised symptoms questionnaire. Grades 4-9 rose Bengal staining were considered as positive dry eye and were compared with grades 0-3 staining eyes as negative controls. Mean tear meniscus height, Schirmer's test and TBUT were lower among cases than their corresponding control eyes. The difference between the mean Schirmer's test values of cases and their controls were statistically significant (P = 0.00 for right eyes and P = 0.002 for left eyes). Rose Bengal grades were inversely correlated with the mean Schirmer's values (Pearson correlation -0.429, P = 0.05 for right eyes and -0.335, P = 0.03 for left eyes) and TBUT (Pearson correlation -0.316, P = 0.05 for right eyes and -0.212, P = 0.06 for left eyes). About 95.8% of the cases were symptomatic, as opposed to 70.4% of the controls (P = 0.01, Fisher's exact test) and 95.8% of dry right eyes compared to 61.1% of their controls had ocular surface abnormalities (P = 0.001), while 89.5% of dry left eyes compared to 62.7% of controls had surface abnormalities (P = 0.07). A close relationship exists between ocular irritation symptoms, surface abnormalities and functional evidence of tear instability. Such patients should be treated empirically or screened for dry eyes.

COMPARAÇÃO ENTRE DOIS MÉTODOS DE COLORAÇÃO PARA ANÁLISE MORFOLÓGICA E ACROSSOMAL DE ESPERMATOZÓIDES DE GATO DOMÉSTICO (Felis catus).

The objective of this study was to evaluate the efficiency of the modified Karras staining technique (KA) to analyze domestic cat sperm morphology by comparing it with the Fast Green FCF/ Rose Bengal staining (FR), previously used for this species. Four adult cats were used, from which sperm samples were collected four times in alternate days for each tom using an artificial vagina (n=16 ejaculates). Both staining techniques were performed for each ejaculate. For the FR staining technique, the semen in natura was diluted in 2.9% sodium citrate and, afterwards, in the staining solution. After 70 seconds, smears were made onto slide and dried at 37oC. For the KA staining technique, previously made and formol saline fixed slides were sequentially immersed in Rose Bengal solution, Tannin solution, and Victoria Blue B solution, and dried at room temperature. For sperm evaluation, 200 sperm cells were assessed for each staining technique in all ejaculate samples using a bright field microscope at 1000X magnification. Statistical analysis used the non-parametric Wilcoxon test, establishing significance at p<0.05. For the KA staining technique, higher percentage of distal cytoplasmic droplets and lower percentage of sperm head defects were obtained when compared to the FR staining technique. This way, both staining techniques were not totally efficient for the assessment of morphological defects found in the domestic cat in natura spermatozoa. KEY WORDS: Acrosome, domestic cat, spermatozoa, sperm morphology, staining.

Long-term Follow-up of Punctal and Proximal Canalicular Stenoses After Silicone Punctal Plug Treatment in Dry Eye Patients

To determine the clinical value and relevance of punctal and proximal canalicular stenoses after punctal plug therapy in moderate to severe dry eye syndrome. Retrospective, observational case series. Seventeen eyes were determined to have punctum or proximal canalicular stenoses after spontaneous loss of a collared silicone punctal plug. After initial diagnosis all patients had 12 months or more of follow-up (mean, 39; range, 12 to 87 months). The clinical data collected included gender and age of patients, localization of the stenosis, plug size, duration of punctal occlusion, subjective symptoms, objective ocular surface disease parameters, and occurrence of complications. A statistically significant correlation between localization of the stenosis and plug size, and localization of the stenosis and duration of punctal occlusion could not be found. At follow-up, subjective symptoms (P < .01) and frequency of artificial tear application (P < .001) were significantly reduced compared to data before plug insertion. Schirmer I test results (P < .001), corneal fluorescein staining (P < .01), and rose bengal staining (P < .001) improved significantly, whereas tear break-up time (P < .2) and impression cytology scores of the conjunctival surface (P = .2) remained almost unchanged. Complications could not be found. Within the observation period of up to seven years, all stenoses remained asymptomatic. Additionally, subjective symptoms and most dry eye parameters in our study population improved.

Tear cytokine and ocular surface alterations following brief passive cigarette smoke exposure

Purpose: To prospectively investigate the effects of acute passive cigarette smoke exposure on the ocular surface and tear film in healthy non-smokers. Methods: Twelve right eyes of 12 subjects without any ocular diseases were examined before, 5min, and 24h after 5min of passive cigarette smoke exposure in a controlled smoke chamber. Tear samples were obtained before, 5min and 24h after smoke exposure to detect tear hexanoyl-lysine (HEL), acrolein and inflammatory cytokine concentrations. Tear evaporation rate, DR-1 tear film lipid layer interferometry, tear film break-up time (TBUT), ocular surface fluorescein staining (FS) and Rose Bengal staining (RB), Schirmer I test were performed before, 5min, and 24h after smoke exposure. Conjunctival impression cytology (IC) and brush cytology (BC) were carried out before and 24h after smoke exposure. Results: Tear evaporation rate, tear lipid spread time, tear film break-up time, and vital staining scores showed significant worsening with passive smoke exposure. Tear HEL and IL-6 concentrations increased significantly 24h after smoke exposure. Tear acrolein level showed an insignificant increase at 5min. IC and RT-PCR revealed a significant reduction in goblet cell density, a shift toward higher squamous metaplasia grades and a significant downregulation of MUC5AC mRNA expression at 24h. Conclusion: Even brief passive exposure to cigarette smoke in healthy non-smoker subjects was associated with adverse effects on the ocular surface health as evidenced by an increase of tear inflammatory cytokines, tear lipid peroxidation products and decrease of mucosal defense resulting in tear instability and damage to the ocular surface epithelia.

Eosinophils adhere to and stimulate replication of lung fibroblasts ‘in vitro’

Eosinophils have been implicated in several disorders associated with the development of fibrosis. This led us to investigate the interactions between eosinophils and fibroblasts in vitro. Adhesion between purified guinea pig peritoneal eosinophils and monolayers of human fetal lung fibroblasts was assessed using the rose bengal dye staining assay. Fibroblast replication was assessed using a colorimetric assay based upon the uptake and subsequent release of methylene blue. Addition of phorbol myristate acetate induced a rapid, time-dependent increase in eosinophil adhesion (127% and 328% over basal adhesion after 10 and 30 min, respectively). Phorbol myristate acetate-induced adhesion was inhibited by the peptides RGDS and GRGDS (48% and 42%, respectively using 1 mM peptide) and by nordihydroguaiaretic acid, an inhibitor of the lipoxygenase pathway of arachidonic acid metabolism (46% inhibition at 15 microM). In addition, 24 h culture of fibroblast monolayers with interleukin 1 alpha (IL-1 alpha) or tumour necrosis factor alpha (TNF alpha) resulted in enhanced adhesion (10 U/ml IL-1 alpha stimulated adhesion by 55% of control, 500 U/ml TNF alpha by 75% of control). Conditioned media from cultured eosinophils stimulated fibroblast replication in a time-dependent fashion with maximal stimulation at 3 h. In contrast, media from guinea pig peritoneal macrophages in culture did not show such an effect. This study indicates that eosinophils are capable of both adhering to and releasing mitogens for fibroblasts in vitro. These observations suggest that eosinophils have the capacity to play a role in the development of fibrosis in disorders where they have been shown to be present.

Corneal In Vivo Confocal Scanning Laser Microscopy in Patients with Atopic Keratoconjunctivitis

To elucidate the morphologic alterations of the cornea in atopic keratoconjunctivitis (AKC) using confocal microscopy (Heidelberg Retina Tomograph II-Rostock Cornea Module: HRT-II RCM). Prospective comparative study. We studied 21 right eyes of 21 AKC patients (11 males, 10 females; mean age, 26.3 years) as well as 19 right eyes of 19 normal subjects (12 males, 7 females; mean age, 28.4 years). All subjects underwent corneal sensitivity measurements, Schirmer test, tear film break-up time, fluorescein and Rose Bengal stainings, and HRT-II confocal laser scanning microscopy of the central cornea. The epithelial and endothelial cell densities of the central cornea, the density of subbasal long nerve fibers (LNFs) and total nerve branches (NBs) of the subbasal nerve plexus were calculated. The morphologic characteristics of the corneal nerves were studied. Correlation between nerve density, tear functions, and ocular surface examination parameters were investigated. The corneal sensitivity, tear stability and vital staining scores were significantly worse in eyes with AKC (P<0.01). Eyes with AKC showed a significantly lower density of basal epithelial cells, LNFs, and NBs compared with normal eyes. Nerve fiber abnormalities such as increased tortuosity, bifurcation abnormality, sharp deflections, and thickening of stromal nerves, as well as several inflammatory cells in close proximity of the subbasal and stromal nerve fibers were observed. The corneal disease in AKC was associated with significant alterations of the basal epithelium, and subbasal and stromal corneal nerves, which related to the changes in tear functions and corneal sensitivity. Confocal scanning laser microscopy was useful to study the pathological in vivo corneal changes in AKC.

Tear Film Function in Type 2 Diabetic Patients with Retinopathy

Purpose: To investigate whether diabetes mellitus is correlated with tear film dysfunction. Methods: Tear film function tests including tear film breakup time (BUT), fluorescein staining, Schirmer I test, rose Bengal staining, total tear protein detection, tear sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and TMS-4 corneal topography were performed. A dry-eye questionnaire was used. Results: Compared with the control group and nonproliferative diabetic retinopathy (NPDR) group, in the proliferative diabetic retinopathy (PDR) group, the BUT and the value of the Schirmer I test were reduced significantly (p < 0.01); corneal fluorescein staining scores, the positive rate of rose Bengal staining and the surface regularity index (SRI) and surface asymmetry index (SAI) were higher (p < 0.01); concentrations of lactoferrin and tear-specific prealbumin were lower (p < 0.01, p < 0.05, respectively). In diabetic patients, the SRI and SAI were positively correlated with fluorescein staining scores (r = 0.754, 0.480, p < 0.01, respectively), and the dry-eye symptoms were significantly related to an abnormal BUT and Schirmer I test (p < 0.01, respectively). Conclusion: The declined tear film function is severer in the patients with PDR than in those with NPDR. Besides the traditional methods, tear SDS-PAGE and TMS corneal topographic indices contribute to the discovery of tear film dysfunction in diabetic patients.

SmartPlug Versus Silicone Punctal Plug Therapy for Dry Eye

To evaluate the clinical efficacy, retention rates, and complications of SmartPlug insertion compared with silicone punctal plugs in patients with dry eye. Thirty-six eyes with subjective symptoms of dry eye in addition to a tear film breakup time (TBUT) <5 seconds and evidence of ocular surface damage on rose Bengal or fluorescein staining were included. Treated eyes were randomized to either a silicone plug or SmartPlug inferior punctal occlusion. Pre- and posttreatment evaluations included subjective symptom scoring, tear meniscus height, TBUT, Schirmer test, fluorescein and rose Bengal staining, and artificial tear use. After a mean follow-up period of 11.2 weeks, both the silicone plug- and SmartPlug-treated eyes showed significant improvement in symptom scoring (P = 0.002 and P = 0.005, respectively), TBUT (P = 0.035 and P = 0.009, respectively), and fluorescein (P = 0.024 and P = 0.016, respectively) and rose Bengal (P = 0.008 and P = 0.046, respectively) staining. There was no significant difference in these parameters between the 2 plugs. SmartPlug-, but not the silicone plug-treated eyes showed significant improvement in mean tear meniscus height (P = 0.037). The use of artificial tear supplements was reduced in 10 (55.6%) silicone- and 11 (61.1%) SmartPlug-treated eyes. Minor complications related to plug insertion were experienced in 4 (22%) silicone- and 2 (11%) SmartPlug-treated eyes. Spontaneous plug loss occurred with 6 (33%) silicone plugs. This prospective randomized trial shows that SmartPlug insertion has equivalent clinical efficacy to the use of conventional silicone plugs. Both SmartPlug and silicone plug use can reduce dependency on tear supplements in >55% of patients with dry eye.

A Rabbit Dry Eye Model Induced by Topical Medication of a Preservative Benzalkonium Chloride

To establish a rabbit dry eye model with topical medication of the ocular preparation preservative benzalkonium chloride (BAC). Sixteen white rabbits were used. One eye of each rabbit was chosen randomly for topical administration of 0.1% BAC twice daily for 14 days. The other untreated eyes served as controls. Schirmer test, fluorescein, and rose bengal staining were performed before and after BAC treatment on days 3, 5, 7, and 14. Conjunctiva impression cytology specimens were collected on days 0, 7, and 14. The rabbits were killed after day 14. Immunofluorescence staining was performed to detect mucin-5 subtype AC (MUC5AC) on conjunctival cryosections. Cornea and conjunctiva structures were evaluated by light and electron microscopy. Compared with untreated controls, BAC-treated eyes showed significant decreases in Schirmer scores (P = 0.01) and increases in fluorescein scores (P < 0.001) on days 5, 7, and 14. A significant increase in rose bengal scores was noticed as early as day 3 (P = 0.001). Decreases in goblet cell density occurred on days 7 and 14 (P = 0.001). Decreased MUC5AC and histopathologic and ultrastructural disorders of the cornea and conjunctiva were also observed in the BAC group. These findings demonstrated that an ophthalmic preservative, benzalkonium chloride, induced a dry eye syndrome in rabbits with damage to the cornea and conjunctiva, decreased aqueous tear basal secretion, goblet cell loss, and MUC5AC deficiency. This rabbit model was consistent with human dry eye syndrome in both aqueous tear and mucin deficiency and may be appropriate for studying dry eye syndrome.

Release of Membrane-Associated Mucins from Ocular Surface Epithelia

Three membrane-associated mucins (MAMs)--MUC1, MUC4, and MUC16--are expressed at the ocular surface epithelium. Soluble forms of MAMs are detected in human tears, but the mechanisms of their release from the apical cells are unknown. The purpose of this study was to identify physiologic agents that induce ocular surface MAM release. An immortalized human corneal-limbal epithelial cell line (HCLE) expressing the same MAMs as native tissue was used. An antibody specific to the MUC16 cytoplasmic tail was developed to confirm that only the extracellular domain is released into the tear fluid or culture media. Effects of agents that have been shown to be present in tears or are implicated in the release or shedding of MAMs in other epithelia (neutrophil elastase, tumor necrosis factor [TNF]), TNF-alpha-converting enzyme, and matrix metalloproteinase-7 and -9) were assessed on HCLE cells. HCLE cell surface proteins were biotinylated to measure the efficiency of induced MAM release and surface restoration. Effects of induced release on surface barrier function were measured by rose bengal dye penetrance. MUC16 in tears and in HCLE-conditioned medium lacked the cytoplasmic tail. TNF induced the release of MUC1, MUC4, and MUC16 from the HCLE surface. Matrix metalloproteinase-7 and neutrophil elastase induced the release of MUC16 but not of MUC1 or MUC4. Neutrophil elastase removed 68% of MUC16, 78% of which was restored to the HCLE cell surface 24 hours after release. Neutrophil elastase-treated HCLE cells showed significantly reduced rose bengal dye exclusion. Results suggest that the extracellular domains of MUC1, MUC4, and MUC16 can be released from the ocular surface by agents in tears. Neutrophil elastase and TNF, present in higher amounts in the tears of patients with dry eye, may cause MAM release, allowing rose bengal staining.

Preoperative Characteristics and a Potential Mechanism of Chronic Dry Eye after LASIK

To determine whether measurable preoperative characteristics predispose patients to chronic dry eye after laser in situ keratomileusis (LASIK). The study consisted of 24 eyes of 24 patients who underwent LASIK. Tear breakup time, Schirmer testing with and without anesthesia, rose bengal staining, central corneal sensitivity, nucleus-to-cytoplasmic ratio, and goblet cell density were evaluated 2 weeks before and 1 week, 3 months, and 9 months after surgery. Patients were classified into two outcome groups, the nondry-eye group (NDEG) and the chronic dry-eye group (CDEG), on the basis of dry eye status 9 months after surgery. The authors tested whether preoperative values of each parameter were associated with the development of chronic dry eye. All parameters, except rose bengal staining, deteriorated significantly after surgery but returned to preoperative levels within 3 to 9 months. The CDEG had significantly lower preoperative Schirmer test values with and without anesthesia and were delayed in recovery after surgery in goblet cell density, rose bengal staining, Schirmer test values without anesthesia, and tear breakup time. Results of preoperative Schirmer tests without anesthesia positively correlated with tear breakup time 9 months after surgery. Preoperative tear volume may affect recovery of the ocular surface after LASIK and may increase the risk for chronic dry eye.