Polyhexanide based contact lens storage fluids frequently exhibit insufficient antifungal activity against Fusarium species

PURPOSE

Fusarium keratitis is a severe infection of the anterior eye, frequently leading to keratoplasty or surgical removal of the affected eye. A major risk factor for infection is the use of contact lenses. Inadequate hygiene precautions and mold-growth permissive storage fluids are important risk factors for fungal keratitis. The aim of this study was to comparatively analyze contact lens storage fluids disinfection efficacy against Fusarium species.

METHODS

Eleven commercially available storage fluids were tested. The storage fluids were classified according to their active ingredients myristamidopropyldimethylamine (Aldox), polyhexanide and hydrogen peroxide. Efficacy was tested against isolates belonging to the Fusarium solani and Fusarium oxysporum species complexes as the most common agents of mould keratitis. Tests were carried out based on DIN EN ISO 14729.

RESULTS

All Aldox and hydrogen peroxide (H2O2) based fluids were effective against Fusarium spp., while the majority of polyhexanide based storage fluids showed only limited or no antifungal effects. Efficacy of polyhexanide could be restored by the addition of the pH-regulating agent tromethamine - an additive component in one commercially available product.

CONCLUSIONS

In summary, the use of Aldox- or hydrogen peroxide-based storage fluids may reduce the risk of Fusarium keratitis, while polyhexanide-based agents largely lack efficacy against Fusarium.

Innovative cold atmospheric plasma (iCAP) decreases corneal ulcer formation and bacterial loads and improves anterior chamber health in methicillin resistant Staphylococcus aureus keratitis

Bacterial keratitis is a vision-threatening infection of the cornea that is typically treated with antibiotics. However, antibiotics sometimes fail to eradicate the infection and do not prevent or repair the damage caused directly by the bacteria or the host immune response to the infection. Our group previously demonstrated that treatment of Pseudomonas aeruginosa keratitis in rabbits with innovative cold atmospheric plasma (iCAP) resulted in reduced edema, ulcer formation, and bacterial load. In this study, we investigated the efficacy of iCAP treatment in methicillin-resistant Staphylococcus aureus (MRSA). New Zealand white rabbits were infected intrastromally with MRSA then treated with iCAP, moxifloxacin, vancomycin, or combination of iCAP with each antibiotic to assess the safety and efficacy of iCAP treatment compared to untreated controls and antibiotics. iCAP treatment significantly reduced bacterial loads and inflammation, improved anterior chamber clarity, and prevented corneal ulceration compared to untreated controls and antibiotic treatment. Safety assessments of grimace test scores and tear production showed that iCAP was not significantly different from either antibiotic treatment in terms of distress or tear production. Combination iCAP/antibiotic treatment did not appear to provide significant added benefit over iCAP alone. Our findings suggest that the addition of iCAP may be a viable tool in reducing damage to the cornea and anterior chamber of the eye following S. aureus keratitis.

Glutamine alleviates Lipopolysaccharide-induced corneal epithelial inflammation and oxidative stress in dogs

Pseudomonas aeruginosa is a common pathogenic bacteria in canine ophthalmology. Lipopolysaccharide (LPS), a component in the cell wall of gram-negative bacteria, is released following bacterial lysis and causes pathology and inflammation of the cornea. Antibiotics are used to treat bacterial keratitis, and the reuse of antibiotics can easily cause bacterial resistance. Research has shown that glutamine (GLN) has anti-inflammatory and antioxidant biological functions. Herein, we explored the effects and underlying mechanisms of GLN and established an LPS-induced cornea inflammation model. Treatment groups comprised: control check (CK), LPS, LPS + GLN, and Sham groups. Topical GLN treatment alleviated corneal opacity, reduced corneal injury, and accelerated corneal wound healing. Furthermore, GLN treatment altered the uniform distribution of corneal epithelial cells and transformed the healing approach of these cells in the corneal wound from crawling to filling. The expression of Toll-like receptor 4 (TLR4), IL-6, TNF-α, and p-p65 and the activity of myeloperoxidase and superoxide dismutase decreased while the content of malondialdehyde increased in the LPS + GLN group compared with those in the LPS group. Thus, our study suggests that LPS-induced inflammation and oxidative stress may be suppressed via the TLR4/NF-κB signaling pathway by GLN and that GLN could be used as an adjunct therapy to reduce antibiotic use.

A novel technique of penetrating keratoplasty to prevent intraocular contents extrusion for infectious keratitis

PURPOSE

To evaluate the safety and the effectiveness of our novel penetrating keratoplasty for infectious keratitis.

METHODS

Retrospective, noncomparative, interventional case series of patients with infectious keratitis who received the novel penetrating keratoplasty technique were analyzed. A prepared plastic sheet was located between the diseased cornea and iris-lens diaphragm. After the diseased lesions were removed, the graft was positioned on the plastic sheet and sutured to the recipient bed. The plastic sheet was pulled out from the anterior chamber before the all interrupted sutures were placed. The intra- and post-operative complications, the outcome of the graft and the number of corneal endothelial cells were analyzed.

RESULTS

A total of 82 eyes of 82 patients was included. The mean follow-up period was 29 ± 16 months (range from 13 to 45 months). No intraocular content extrusion, simultaneous cataract extraction and suprachoroidal hemorrhage occurred. Direct contact between the infectious cornea and the graft was successfully avoided. Greater than expected endothelial cell reduction or complications were not found.

CONCLUSIONS

This modified technique effectively prevents the extrusion of intraocular contents while avoiding the direct contact with donor endothelium during the procedure. The occurrence rate of complications such as endothelial cell loss is not higher than the conventional methods.

Reduction of disinfection efficacy of contact lens care products on the global market in the presence of contact lenses and cases

Objective

Sight-threatening infections can be caused by pathogenic micro-organisms colonising the cornea, leading to microbial keratitis (MK). These micro-organisms can be introduced to the eye via improper contact lens use and care. MK can also result from ineffective contact lens care solutions (CLCs), even if the patient is following best practice guidelines. Therefore, it is critical to understand the differences between the effectiveness of popular CLCs on the global market.

Methods and analysis

Following the International Standards Organisation standards 14 729 and 18259, bacteria (Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus), fungi (Candida albicans, Fusarium strains) and Acanthamoeba strains were inoculated into each CLC with and without contact lenses, and held for the manufacturer’s stated disinfection time. Plate counts were conducted to determine the number of surviving micro-organisms.

Results

All CLCs examined met the primary log reduction criteria during stand-alone testing for Pseudomonas, Staphylococcus, Candida and Fusarium. renu Multiplus, All Clean Soft, and Kombilösung Super did not meet the primary criteria when challenged with Serratia. Only OPTI-FREE Express exceeded 4 log reduction for both strains of Acanthamoeba tested. We noted a substantial reduction in disinfection efficacy when CLCs were challenged with Fusarium in the presence of lenses and cases versus stand-alone testing. OPTI-FREE Express demonstrated significantly less net log reduction loss than the other four CLCs tested.

Conclusion

Of the popular CLCs on the global market, the product which relies on dual biocides polyquaternium-1 and myristamidopropyl dimethylamine demonstrated the highest disinfection efficacy in microbial disinfection challenges in the absence and presence of contact lenses.

Increased photokeratitis during the coronavirus disease 2019 pandemic: Clinical and epidemiological features and preventive measures

An increased incidence of photokeratitis has occurred during the coronavirus disease 2019 (COVID-19) pandemic due to improper and unprotected use of ultraviolet lamps. Here, we summarize the clinical and epidemiological features of this increased incidence of photokeratitis and share advice in using health education to prevent it.We collected data from patients diagnosed with photokeratitis from October 7, 2019 to December 1, 2019, and from February 17, 2020 to April 12, 2020, and compared the frequency of onset, site of ultraviolet radiation (UVR) exposure, reason for exposure, exposure time, and recovery time. We also implemented and evaluated multiple measures of public health education to prevent increased disease.After the COVID-19 outbreak, the frequency of onset of photokeratitis increased significantly, especially among young women. The main reason for UVR exposure changed from welding to disinfection. The incidence sites varied, and the exposure time was longer. As a result, patients needed a longer time to recover. Positive health education was an useful and convenient measure to prevent the disease.While the COVID-19 pandemic is ongoing, more attention should be paid to public health and implement positive measures to prevent photokeratitis.

Role of IL-36γ/IL-36R Signaling in Corneal Innate Defense Against Candida albicans Keratitis

Purpose

Interleukin (IL)-36 cytokines have been shown to play either beneficial or detrimental roles in the infection of mucosal tissues in a pathogen-dependent manner, but their involvement in fungal keratitis remains elusive. We herein investigated their expression and function in mediating corneal innate immunity against Candida albicans infection.

Methods

Gene expression in mouse corneas with or without C. albicans infection was determined by regular RT- and real-time (q)-PCR, Western blot analysis, ELISA or proteome profile assay. The severity of C. albicans keratitis was assessed using clinical scoring, bacterial counting, and myeloperoxidase (MPO) activity as an indicator of neutrophil infiltration. IL36R knockout mice and IL-33-specific siRNA were used to assess the involvement IL-33 signaling in C. albicans-infected corneas. B6 CD11c-DTR mice and clodronate liposomes were used to define the involvement of dendritic cells (DCs) and macrophages in IL-36R signaling and C. albicans keratitis, respectively.

Results

IL-36γ were up-regulated in C57BL6 mouse corneas in response to C. albicans infection. IL-36 receptor-deficient mice display increased severity of keratitis, with a higher fungal load, MPO, and IL-1β levels, and lower soluble sIL-1Ra and calprotectin levels. Exogenous IL-36γ prevented fungal keratitis pathogenesis with lower fungal load and MPO activity, higher expression of sIL-1Ra and calprotectin, and lower expression of IL-1β, at mRNA or protein levels. Protein array analysis revealed that the expression of IL-33 and REG3G were related to IL-36/IL36R signaling, and siRNA downregulation of IL-33 increased the severity of C. albicans keratitis. Depletion of dendritic cells or macrophages resulted in severe C. albicans keratitis and yet exhibited minimal effects on exogenous IL-36γ-induced protection against C. albicans infection in B6 mouse corneas.

Conclusions

IL-36/IL36R signaling plays a protective role in fungal keratitis by promoting AMP expression and by suppressing fungal infection-induced expression of proinflammatory cytokines in a dendritic cell- and macrophage-independent manner.

The Regulating Role of SB216763 in Pseudomonas aeruginosa Keratitis

BACKGROUND

Glycogen synthase kinase 3 beta (GSK3b) is a multifunctional molecule, which plays a critical role in the regulation of various signaling pathways including cell proliferation, growth and development, and inflammation. However, whether GSK3b is involved in the pathological process of Pseudomonas aeruginosa keratitis remains unknown.

METHODS

First, western blots were performed to measure the phosphorylated level of GSK3β at Ser9 (inactive form) in an animal model of Pseudomonas aeruginosa keratitis. Second, the keratitis model received the GSK3β inhibitor SB216763, and the inflammation of cornea was evaluated by clinical scores and slit photos. The expressions of inflammatory cytokines were assessed by real-time PCR, and the corneal bacterial burden was determined by plate count.

RESULTS

The phosphorylated level of GSK3β at Ser9 in the cornea markedly decreased after Pseudomonas aeruginosa infection. The inhibition of GSK3β by SB216763 significantly ameliorated the progress of corneal disease and alleviated corneal opacity. SB216763 suppressed the expression of inflammatory cytokines IL-6 and IL-1b, but exhibited no effects on TNF-a and IL-10 expression. SB216763 dramatically decreased cornea bacterial burden at 5 days after infection with Pseudomonas aeruginosa.

CONCLUSIONS

The activity of GSK3b was enhanced in Pseudomonas aeruginosa keratitis. The inhibition of GSK3β by SB216763 promoted host resistance against Pseudomonas aeruginosa keratitis, via down regulating inflammatory cytokines and bacterial burden.

Diquafosol Sodium Inhibits Apoptosis and Inflammation of Corneal Epithelial Cells Via Activation of Erk1/2 and RSK: In Vitro and In Vivo Dry Eye Model

PURPOSE

To evaluate the effect of diquafosol on corneal epithelium in a dry eye model using Transwell culture and a scopolamine-induced dry eye rat model.

METHODS

Desiccation stress induced in an in vitro dry eye model using human corneal epithelial cells was used, and the cells were incubated with or without diquafosol media diluted at 1:100. Reactive oxygen species (ROS) generation was measured using 2',7'-dichlorofluorescein diacetate (DCFH-DA). Apoptosis was analyzed, and levels of phosphorylated Erk1/2, phosphorylated p90RSK, phosphorylated Akt, IκB-α, and NF-κB-p65 were determined. Levels of IL-1β, TNF-α, IL-6, IL-8, and GM-CSF were quantified. To investigate the in vivo effects of diquafosol, we induced dry eye in Wistar rats using scopolamine hydrobromide. The rats were divided into three groups: control, dry eye, and dry eye diquafosol; topical DIQUAS was applied four times daily for 28 days. We used immunohistochemistry to detect the levels of phosphorylated Erk1/2, phosphorylated p90RSK, and IL-1β, and used the TUNEL assay in corneal tissue.

RESULTS

The distribution of highly fluorescent dichlorofluorescein and the proportion of annexin V- and PI-positive cells decreased in the diquafosol medium. Diquafosol increased the levels of phospho-Erk1/2, phospho-90RSK, phospho-Akt, and IκB-α, whereas it significantly decreased the levels of NF-κB-p65, IL-1β, and TNF-α. In vivo, apoptosis was enhanced in dry eye group. This response was markedly reduced and the level of phosphorylated p90RSK and phosphorylated ERK1/2 were upregulated and IL-1β was downregulated by DIQUAS.

CONCLUSIONS

Diquafosol treatment reduced intracellular ROS levels, apoptosis, and inflammation, all of which were increased in the dry eye model through desiccation.

Shifting trends in microbial keratitis following penetrating keratoplasty in Taiwan

To investigate the clinical and microbiological profiles from microbial keratitis following penetrating keratoplasty (PKP) in a tertiary referral center in Taiwan, the medical records of 648 consecutive patients (648 eyes) undergoing PKP between January 2003 and December 2007 were retrospectively reviewed. Patients who subsequently sustained microbial keratitis were enrolled and analyzed for potential risk factors, clinical manifestations, microbiological profiles, complications, graft survival, and final visual outcome. A total number of 42 corneal graft infections (6.5%) were recruited. Mean interval between corneal transplantation and graft infection was 12 ± 9.5 months. Potential risk factors included suture-related problems (31.0%), lid abnormalities (23.8%), persistent epithelial defect (23.8%), contact lens use (14.3%), dry eye (11.9%), and prior rejection episodes (4.8%). Lesions were discovered mostly at the donor-recipient junction ([DRJ] 45.2%). Positive cultures were identified in all of the morbid eyes, of which Pseudomonas aeruginosa was the most common pathogen (38.1%). Despite mandatory hospitalization and topical fortified antibiotics management, complications ensued such as graft failure (71.4%), hypopyon (21.4%), corneal perforation (14.3%), wound dehiscence (11.9%), and endophthalmitis (4.8%). The visual outcome was dismal that graft clarity was achieved in only 12 eyes (28.6%), and that final visual acuity deteriorated to less than 20/200 in 28 eyes (66.7%). In conclusion, microbial keratitis following PKP is a devastating event that severely impairs graft survival rate and postoperative visual outcome which usually occur within the first postoperative year. The incidence of post-PKP microbial keratitis has generally decreased in recent years whilst P. aeroginosa prevails as the leading cause of graft infection in our hospital. Close follow-up by ophthalmologists and elevated self-awareness of patients for at least one year are always encouraged to prevent late-onset infection.

Prophylactic Vancomycin Drops Reduce the Severity of Early Bacterial Keratitis in Keratoprosthesis

BACKGROUND

Artificial cornea transplantation, keratoprosthesis, improves vision for patients at high risk of failure with human cadaveric cornea. However, post-operative infection can cause visual loss and implant extrusion in 3.2-17% of eyes. Long-term vancomycin drops are recommended following keratoprosthesis to prevent bacterial keratitis. Evidence, though, in support of this practice is poor. We investigated whether prophylactic vancomycin drops prevented bacterial keratitis in an animal keratoprosthesis model.

METHODOLOGY

Twenty-three rabbits were assigned either to a prophylactic group (n = 13) that received vancomycin 1.4% drops 5 times/day from keratoprosthesis implantation to sacrifice, or a non-prophylactic group (n = 10) that received no drops. All rabbits had Staphylococcus aureus inoculation into the cornea at 7-12 days post-implantation and were sacrificed at predetermined time-points. Prophylactic and non-prophylactic groups were compared with slit-lamp photography (SLP), anterior segment optical coherence tomography (AS-OCT), and histology, immunohistochemistry and bacterial quantification of excised corneas. Corneal vancomycin pharmacokinetics were studied in 8 additional rabbits.

RESULTS

On day 1 post-inoculation, the median SLP score and mean±SEM AS-OCT corneal thickness (CT) were greater in the non-prophylactic than the prophylactic group (11 vs. 1, p = 0.049 and 486.9±61.2 vs. 327.4±37.1 μm, p = 0.029 respectively). On days 2 and 4, SLP scores and CT were not significantly different. Immunohistochemistry showed a greater CD11b+ve/non-CD11b+ve cell ratio in the non-prophylactic group (1.45 vs. 0.71) on day 2. Bacterial counts were not significantly different between the two groups. Corneal vancomycin concentration (2.835±0.383 μg/ml) exceeded minimum inhibitory concentration (MIC) for Staphylococcus aureus only after 16 days of vancomycin drops. Two of 3 rabbits still developed infection despite bacterial inoculation after 16 days of prophylactic drops.

CONCLUSIONS

Prophylactic vancomycin drops provided short-term benefit, but did not prevent infection. Achieving MIC in the cornea was not sufficient to prevent Staphylococcus aureus keratitis. Patients should continue to be counselled regarding the risk of infection following keratoprosthesis.

Transient downregulation of microRNA-206 protects alkali burn injury in mouse cornea by regulating connexin 43

PURPOSE

Chemical burn in cornea may cause permanent visual problem or complete blindness. In the present study, we investigated the role of microRNA 206 (miR-206) in relieving chemical burn in mouse cornea.

METHOD

An alkali burn model was established in C57BL/6 mice to induce chemical corneal injury. Within 72 hours, the transient inflammatory responses in alkali-treated corneas were measured by opacity and corneal neovascularization (CNV) levels, and the gene expression profile of miR-206 was measured by quantitative real-time PCR (qPCR). Inhibitory oligonucleotides of miR-206, miR-206-I, were intrastromally injected into alkali-burned corneas. The possible protective effects of down-regulating miR-206 were assessed by both in vivo measurements of inflammatory responses and in vitro histochemical examinations of corneal epithelium sections. The possible binding of miR-206 on its molecular target, connexin43 (Cx43), was assessed by luciferase reporter (LR) and western blot (WB) assays. Cx43 was silenced by siRNA to examine its effect on regulating miR-206 modulation in alkali-burned cornea.

RESULTS

Opacity and CNV levels, along with gene expression of miR-206, were all transiently elevated within 72 hours of alkali-burned mouse cornea. Intrastromal injection of miR-206-I into alkali-burned cornea down-regulated miR-206 and ameliorated inflammatory responses both in vivo and in vitro. LR and WB assays confirmed that Cx43 was directly targeted by miR-206 in mouse cornea. Genetic silencing of Cx43 reversed the protective effect of miR-206 down-regulation in alkali-burned cornea.

CONCLUSION

miR-206, associated with Cx43, is a novel molecular modulator in alkali burn in mouse cornea.

[Complications of corneal cross-linking]

BACKGROUND

More than 10 years after the clinical introduction of corneal cross-linking (CXL) the indications and contraindications are still not yet defined. Fundamental for such a list is the incidence of complications.

METHODS

A PubMed search for complications of corneal crosslinking published up to March 2013 was carried out.

RESULTS

The published complication rates ranged from 1 % to 10 % depending on the stage of keratoconus. Early postoperative complications were transient stromal haze, sterile infiltrates, endothelium decompensation, delayed epithelial healing and infectious keratitis. Stromal opacity can be a delayed postoperative event.

CONCLUSIONS

Complications after corneal cross-linking treatment for keratoconus are rare but the management of these complications may need keratoplasty.

TREM-2 promotes host resistance against Pseudomonas aeruginosa infection by suppressing corneal inflammation via a PI3K/Akt signaling pathway

PURPOSE

To explore the role of triggering receptor expressed on myeloid cells 2 (TREM-2) in Pseudomonas aeruginosa (PA) keratitis.

METHODS

BALB/c mice were routinely infected with PA and evaluated at various postinfection time points for corneal expression of TREM-2, by real-time PCR, Western blot, and flow cytometry. Next, BALB/c and C57BL/6 mice were respectively treated with TREM-2 siRNA or agonistic anti-TREM-2 antibody, to determine the role of TREM-2 in PA keratitis. Bacterial load and neutrophil infiltration were tested by plate count and myeloperoxidase assay, respectively. Th1-/Th2-type and proinflammatory cytokine expression were tested by real-time PCR and ELISA after in vivo and in vitro silencing of TREM-2. Moreover, phosphorylated Akt levels were tested by Western blot in murine macrophages after treatment with agonistic anti-TREM-2 antibody. mRNA levels of proinflammatory cytokines were examined in murine macrophages after TREM-2 activation and lipopolysaccharide stimulation, following pretreatment with inhibitors for PI3K or Akt, to determine whether PI3K/Akt is required in TREM-2-mediated immune modulation. In addition, BALB/c mice were treated with wortmannin and analyzed for bacterial load and proinflammatory cytokine expression.

RESULTS

TREM-2 expression was elevated in the infected BALB/c corneas at 3 or 5 days postinfection. Silencing of TREM-2 accelerated disease progression by enhancing bacterial load and corneal inflammation, whereas activation of TREM-2 promoted host resistance to PA keratitis. PI3K/Akt signaling is required in the TREM-2-mediated immune modulation, and inhibition of PI3K resulted in worsened disease after PA corneal infection.

CONCLUSIONS

TREM-2 promoted host resistance to PA infection by suppressing corneal inflammation via activation of the PI3K/Akt pathway.

Extracellular matrix protein lumican promotes clearance and resolution of Pseudomonas aeruginosa keratitis in a mouse model

Lumican is an extracellular protein that associates with CD14 on the surface of macrophages and neutrophils, and promotes CD14-TLR4 mediated response to bacterial lipopolysaccharides (LPS). Lumican-deficient (Lum(-/-)) mice and macrophages are impaired in TLR4 signals; raising the possibility that lumican may regulate host response to live bacterial infections. In a recent study we showed that invitro Lum(-/-) macrophages are impaired in phagocytosis of gram-negative bacteria and in a lung infection model the Lum(-/-) mice showed poor survival. The cornea is an immune privileged barrier tissue that relies primarily on innate immunity to protect against ocular infections. Lumican is a major component of the cornea, yet its role in counteracting live bacteria in the cornea remains poorly understood. Here we investigated Pseudomonas aeruginosa infections of the cornea in Lum(-/-) mice. By flow cytometry we found that 24 hours after infection macrophage and neutrophil counts were lower in the cornea of Lum(-/-) mice compared to wild types. Infected Lum(-/-) corneas showed lower levels of the leukocyte chemoattractant CXCL1 by 24-48 hours of infection, and increased bacterial counts up to 5 days after infection, compared to Lum(+/-) mice. The pro-inflammatory cytokine TNF-α was comparably low 24 hours after infection, but significantly higher in the Lum(-/-) compared to Lum(+/-) infected corneas by 2-5 days after infection. Taken together, the results indicate that lumican facilitates development of an innate immune response at the earlier stages of infection and lumican deficiency leads to poor bacterial clearance and resolution of corneal inflammation at a later stage.

Microbial keratitis as a foreseeable complication of cosmetic contact lenses: a prospective study

PURPOSE

A recent study shows that the relative risk of contact lenses (CL)-related microbial keratitis (MK) is highly increased with cosmetic contact lenses (CosCL). The aim of our study is to illustrate the implications of the CosCL on the occurence of MK and to describe the subpopulation of CosCL wearers.

METHODS

A prospective multicenter study was conducted in 12 French University Hospitals on all lenses wearers presenting with MK between July 2007 and July 2009, including CosCL wearers. Patients had a complete ophthalmological examination and were interviewed by a 50 items anonymous 'questionnaire' to determine subject demographics and lenses wear history. The CosCL-related MK subpopulation (case) was described and finally compared to (noncosmetic) CL-related MK (control).

RESULTS

Two hundred and fifty-six patients were included for contact lenses-related MK. Thirty-two of them (12.5%) were seen for MK after wearing CosCL. Compared with CL, CosCL wearers are younger (21 versus 27 years of age) and recent wearers (3 versus 9 years). CosCL were rarely dispensed by eye care professionals increasing the risk of MK (OR, 12.3). Education about lens care and handling was deficient for most of CosCL wearers (OR, 26.5). Sixty per cent of CosCL cases versus 13% of CL-related MK had a final visual acuity less than 20/200.

CONCLUSION

Patients who acquire CosCL are less likely to be instructed on appropriate lenses use and basic hygiene rules. Consequently, CosCL wearers are experiencing acute vision-threatening infections.

Effect of topical azithromycin on corneal innate immune responses

PURPOSE

To determine the effect of azithromycin (AZM) in a murine model of corneal inflammation.

METHODS

The effect of topical AZM was studied in murine corneal inflammation. Corneal inflammation was induced by thermal cautery in BALB/c mice. Leukocyte infiltration at different time points was analyzed by flow cytometry. At set time points, real-time polymerase chain reaction was performed to quantify the expression of different inflammatory cytokine transcript in the cornea. Corneal samples were analyzed immunohistochemically for the expression of intercellular adhesion molecule-1 (ICAM-1). Corneal neovascularization (CNV) was induced by micropellet (VEGF-A) placement. Mice were then treated topically with either AZM or vehicle. CNV was evaluated morphometrically.

RESULTS

Eyes receiving AZM showed a significant decrease in corneal infiltration compared with the vehicle-treated group. AZM also significantly decreased messenger RNA expression levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and ICAM-1 in the cornea. There was no significant difference in CNV between the AZM- and vehicle-treated groups.

CONCLUSIONS

After an inflammatory insult, topical AZM significantly reduced leukocyte infiltration into the cornea. This was further supported by an associated decrease in expression of IL-1β, TNF-α, and ICAM-1 in the cornea, indicating AZM may have a potential anti-inflammatory effect on corneal inflammation.

Parstatin suppresses ocular neovascularization and inflammation

PURPOSE

Parstatin is a 41-mer peptide formed by proteolytic cleavage on activation of the PAR1 receptor. The authors recently showed that parstatin is a potent inhibitor of angiogenesis. The purpose of the present study was to evaluate the therapeutic effect of parstatin on ocular neovascularization.

METHODS

Choroidal neovascularization was generated in mice using laser-induced rupture of Bruch's membrane and was assessed after 14 days after perfusion of FITC-dextran. Oxygen-induced retinal neovascularization was established in neonatal mice by exposing them to 75% O(2) at postnatal day (P)7 for 5 days and then placing them in room air for 5 days. Evaluation was performed on P17 after staining with anti-mouse PECAM-1. The effect of parstatin was tested after intravitreal administration. The effects of subconjunctival-injected parstatin on corneal neovascularization and inflammation in rats were assessed 7 days after chemical burn-induced corneal neovascularization. Retinal leukostasis in mice was assessed after perfusion with FITC-conjugated concanavalin A.

RESULTS

Parstatin potently inhibited choroidal neovascularization with an IC(50) of approximately 3 μg and a maximum inhibition of 59% at 10 μg. Parstatin suppressed retinal neovascularization with maximum inhibition of 60% at 3 μg. Ten-microgram and 30-μg doses appeared to be toxic to the neonatal retina. Subconjunctival parstatin inhibited corneal neovascularization, with 200 μg the most effective dose (59% inhibition). In addition, parstatin significantly inhibited corneal inflammation and VEGF-induced retinal leukostasis. In all models tested, scrambled parstatin was without any significant effect.

CONCLUSIONS

Parstatin is a potent antiangiogenic agent of ocular neovascularization and may have clinical potential in the treatment of angiogenesis-related ocular disorders.

Protective role of gammadelta T cells in spontaneous ocular inflammation

PURPOSE

A role for gammadelta T cells in immunoregulation has been shown in a number of studies, but in the absence of infection or induced disease, mice lacking gammadelta T cells generally appear to be healthy. That certain mice lacking gammadelta T cells often spontaneously develop keratitis, characterized by a progressive and destructive inflammation of the cornea is reported here.

METHODS

The keratitis developing in these mice was characterized in terms of prevalence in males versus females, age of onset, and histologic features. Attempts were made to understand the underlying causes of the disease by removing alphabeta T cells, altering sex hormones, and reconstituting gammadelta T cells.

RESULTS

The development of keratitis in these mice depended on the C57BL/10 genetic background, and was much more common among females than males. The incidence of the disease increased with age, exceeding 80% in females greater than 18 weeks old. Evidence that the keratitis in these mice is at least partly autoimmune in nature, and that despite its prevalence in females, male hormones do not protect against the disease is presented.

CONCLUSIONS

These findings indicate an important role for gammadelta T cells in maintaining immune balance in the eye. The mice described in this study represent a potential new small animal model of keratitis.

The red eye in contact lens wearers--a high risk presentation

Sore eyes are a common primary care presentation. Within this group, contact lens wearers are at risk of developing serious complications and should be identified accordingly. Contact lens associated bacterial keratitis is a sight pathogen from corneal scrapings in patients who wear contact lenses and develop this condition. Pseudomonas is not sensitive to chloramphenicol and as such, will not respond to the most commonly prescribed antibiotic for sore eyes. These patients require urgent referral for corneal scrapings to allow culture and sensitivity, which will direct treatment.

Outcomes of periocular reconstruction for facial nerve paralysis in cancer patients

BACKGROUND

Facial nerve paralysis is a common event in patients with head and neck cancer or metastasis of cancer to the parotid region. The aim of this study was to evaluate the outcomes of periocular reconstruction for facial nerve paralysis in cancer patients.

METHODS

The medical records of all patients who had undergone periocular surgery for facial nerve paralysis between January of 1999 and December of 2003 were retrospectively reviewed. The outcome measures included the ocular symptoms and signs, improvement in symptoms of exposure keratopathy postoperatively, timing of periocular surgery in relation to radiotherapy, and surgical complications.

RESULTS

Preoperative symptoms included burning sensation (25 of 78 patients), difficulty with vision (30 of 78), frequent use of lubricating drops and ointments (52 of 78), and excessive tearing (37 of 78). The degree of lagophthalmos ranged from 1.5 to 12 mm (mean, 6.5 mm) preoperatively and from 0 to 4.5 mm (mean, 1.5 mm) postoperatively. Seventy-eight patients had gold weight placement; 72 of them also had lateral tarsorrhaphy, 56 had lower eyelid tightening via a lateral tarsal strip procedure in addition to the gold weight and lateral tarsorrhaphy, and 22 had brow elevation in addition to all the above-mentioned procedures. Four also required a medial tarsorrhaphy. All patients reported less dependence on lubricating drops and ointments after periocular surgery. Eighteen of 25 patients who had foreign body sensation as their main preoperative symptom experienced improvement after surgery. Forty-four patients had radiotherapy to the head and neck region. Twenty-seven patients completed radiotherapy before and 17 after periocular reconstruction. Complication rates were low and comparable in both preoperative and postoperative radiation groups.

CONCLUSIONS

Periocular reconstruction for facial paralysis results in improvement of exposure keratopathy and less dependence on lubricating drops and ointments. Complications are minimal and infrequent. The timing of external beam radiotherapy does not affect the outcomes of periocular surgery.

Efficacy of Contact Lens Multipurpose Solutions Against Serratia Marcescens

PURPOSE

To compare the susceptibilities of clinical isolates of Serratia marcescens and the standard ISO ATCC 13880 strain to five contact lens multipurpose disinfection solutions (MPDSs).

METHODS

Five commercially available MPDSs, containing either a polymeric biguanide or polyquaternium, were tested using ISO/CD 14729 stand-alone test for contact lens care products against four ocular isolates of S. marcescens and the strain ATCC 13880. An average log reduction in bacterial numbers at the manufacturer's minimum recommended disinfection time was determined and compared with the criteria for stand-alone disinfection products for each MPDS against each bacterial strain.

RESULTS

All the MPDSs tested met the stand-alone criteria of 3-log reduction of viable bacteria against the ATCC strain of S. marcescens. However, there was more variability in their ability to meet disinfection criteria when tested against the clinical isolates. Two of the clinical isolates were significantly more resistant to disinfection than was the recommended ISO strain (p < or = 0.034). Two of the polyquaternium-1-based disinfection solutions (solutions D and E, p < or = 0.005) were less effective overall than the other MPDSs against S. marcescens.

CONCLUSIONS

The importance of strain selection for the testing of MPDSs is indicated, and the use of a single laboratory strain may be insufficient to provide assurance that the disinfection solution will be effective against clinical isolates. Furthermore, clinical isolates of S. marcescens may show increased resistance to disinfection with polyquaternium.

A protective role for IL-6 in staphylococcal microbial keratitis

PURPOSE

To determine whether interleukin-6 (IL-6) plays a protective role in Staphylococcus aureus keratitis in a gene knockout (gko) mouse model and to determine whether IL-6 may be used as a therapy to modulate host responses and control bacterial infection, thereby reducing scarring.

METHODS

The eyes of IL-6 gko mice and wild-type mice were challenged topically with S. aureus and examined at 24 hours after infection. Keratitis was examined clinically and histologically. Bacterial and polymorphonuclear leukocytes (PMNs) were enumerated, and cytokine and chemokine levels were determined by ELISA. Exogenous IL-6 was administered to both IL-6 gko and wild-type mice, and clinical parameters were determined.

RESULTS

IL-6 gko mice showed more severe disease, with increased bacterial counts and PMNs, than did wild-type mice. Changes in levels of chemokines and cytokines were also observed. Administration of exogenous IL-6 resulted in an improved outcome in IL-6 gko mice, with a threefold reduction in bacterial load.

CONCLUSIONS

The data suggest an important regulatory role for IL-6 in modulating excessive inflammatory responses and in controlling bacterial proliferation. IL-6 may play a role in the priming and activation of neutrophils. It could represent a broad-spectrum therapy to improve outcomes in patients who have these potentially blinding infections.

SIGIRR promotes resistance against Pseudomonas aeruginosa keratitis by down-regulating type-1 immunity and IL-1R1 and TLR4 signaling

Pseudomonas aeruginosa keratitis destroys the cornea in susceptible Th1 responder C57BL/6 (B6), but not resistant Th2 responder (BALB/c) mice. To determine whether single Ig IL-1R-related molecule (SIGIRR) played a role in resistance, mRNA and protein expression levels were tested. Both were constitutively expressed in the cornea of the two mouse groups. A disparate mRNA and protein expression pattern was detected in the cornea of BALB/c vs B6 mice after infection. SIGIRR protein decreased significantly in BALB/c over B6 mice at 1 day postinfection. Thus, BALB/c mice were injected with an anti-SIGIRR Ab or IgG control. Anti-SIGIRR Ab over control-treated mice showed increased corneal opacity, stromal damage, and bacterial load. Corneal mRNA levels for IL-1beta, MIP-2, IL-1R1, TLR4, IL-18, and IFN-gamma and protein levels for IL-1beta and MIP-2 also were significantly up-regulated in anti-SIGIRR Ab over control mice, while no changes in polymorphonuclear cell number, IL-4, or IL-10 mRNA expression were detected. To further define the role of SIGIRR, RAW264.7 macrophage-like cells were transiently transfected with SIGIRR and stimulated with heat-killed P. aeruginosa or LPS. SIGIRR transfection significantly decreased mRNA levels for IL-1R1, TLR4, and type 1 immune response-associated cytokines (IL-12, IL-18, and IFN-gamma) as well as proinflammatory cytokines IL-1beta and MIP-2 protein expression. SIGIRR also negatively regulated IL-1 and LPS, but not poly(I:C)-mediated signaling and NF-kappaB activation. These data provide evidence that SIGIRR is critical in resistance to P. aeruginosa corneal infection by down-regulating type 1 immunity, and that it negatively regulates IL-1 and TLR4 signaling.

Prevention of Bacterial Colonization of Contact Lenses With Covalently Attached Selenium and Effects on the Rabbit Cornea

PURPOSE

Although silicone hydrogel materials have produced many corneal health benefits to patients wearing contact lenses, bacteria that cause acute red eye or corneal ulcers are still a concern. A coating that inhibits bacterial colonization while not adversely affecting the cornea should improve the safety of contact lens wear. A covalent selenium (Se) coating on contact lenses was evaluated for safety using rabbits and prevention of bacterial colonization of the contact lenses in vitro.

METHODS

Contact lenses coated with Se were worn on an extended-wear schedule for up to 2 months by 10 New Zealand White rabbits. Corneal health was evaluated with slit-lamp biomicroscopy, pachymetry, electron microscopy, and histology. Lenses worn by the rabbits were analyzed for protein and lipid deposits. In addition, the ability of Se to block bacterial colonization was tested in vitro by incubating lenses in a Pseudomonas aeruginosa broth followed by scanning electron microscopy of the contact lens surface.

RESULTS

The covalent Se coating decreased bacterial colonization in vitro while not adversely affecting the corneal health of rabbits in vivo. The Se coating produced no noticeable negative effects as observed with slit-lamp biomicroscopy, pachymetry, electron microscopy, and histology. The Se coating did not affect protein or lipid deposition on the contact lenses.

CONCLUSION

The data from this pilot study suggest that a Se coating on contact lenses might reduce acute red eye and bacterial ulceration because of an inhibition of bacterial colonization. In addition, our safety tests suggest that this positive effect can be produced without an adverse effect on corneal health.

N-chlorotaurine is an effective antiviral agent against adenovirus in vitro and in the Ad5/NZW rabbit ocular model

PURPOSE

To determine whether N-chlorotaurine (NCT) demonstrates antiviral activity against adenovirus (Ad) in vitro and in the Ad5/NZW rabbit ocular model.

METHODS

The in vitro activity of NCT was evaluated by incubating different Ad serotypes with several concentrations of NCT for 1 hour and determining the reduction in Ad titers. In rabbit study 1, Ad5-infected eyes were treated with 2.5%, 2.0%, and 1.0% NCT; 0.5% cidofovir; or saline. NCT and saline groups were treated 10 times for 1 day and then 5 times daily for 6 days. In rabbit study 2, Ad5-infected eyes were treated with 1.0% NCT/0.1% ammonium chloride (NH4Cl), 0.1% NCT/1.0% NH4Cl, 0.1% NCT/0.1% NH4Cl, and 0.5% cidofovir or saline. The NCT and saline groups were treated five times daily for 10 days. Cidofovir-treated eyes received the authors' standard cidofovir dose regimen: twice daily for 7 days.

RESULTS

In vitro, NCT demonstrated concentration-dependent direct inactivation of all ocular Ad serotypes tested. Rabbit study 1: 2.5%, 2.0%, 1.0% NCT, and cidofovir demonstrated significantly fewer positive cultures per total cultures during days 1 to 14, compared with saline. Rabbit study 2: 1.0% NCT/0.1% NH4Cl, 0.1% NCT/1.0% NH4Cl, 0.1% NCT/0.1% NH4Cl, and cidofovir demonstrated significantly fewer positive cultures per total cultures, during days 1 to 14; shorter durations of shedding; and lower mean combined titers, during days 7 to 14, compared with saline. Cidofovir was significantly more effective than NCT in several outcome measures in both rabbit studies.

CONCLUSIONS

NCT demonstrated antiviral activity against adenovirus in vitro and in vivo. Further development of NCT as a topical antimicrobial is indicated.

A live-attenuated Pseudomonas aeruginosa vaccine elicits outer membrane protein-specific active and passive protection against corneal infection

Pseudomonas aeruginosa can cause sight-threatening corneal infections in humans, particularly those who wear contact lenses. We have previously shown that a live-attenuated P. aeruginosa vaccine given intranasally protected mice against acute lethal pneumonia in a lipopolysaccharide (LPS) serogroup-specific manner. In the current study, we evaluated the protective and therapeutic efficacies, as well as the target antigens, of this vaccine in a murine corneal infection model. C3H/HeN mice were nasally immunized with the vaccine (an aroA deletion mutant of strain PAO1, designated PAO1DeltaaroA) or with Escherichia coli as a control and were challenged 3 weeks later by inoculating the scratch-injured cornea with P. aeruginosa. For passive prophylaxis and therapy, we utilized a serum raised in rabbits nasally immunized with PAO1DeltaaroA or E. coli. Outcome measures included corneal pathology scores and, in some experiments, reductions in total and internalized bacterial CFU. We found that both active and passive immunization reduced corneal pathology scores after challenge with a variety of P. aeruginosa strains, including several serogroup-heterologous strains. Even when given therapeutically starting as late as 24 h after infection, the rabbit antiserum to PAO1DeltaaroA was effective at reducing corneal pathology scores. Immunotherapy of established infections also reduced the numbers of total and internalized corneal P. aeruginosa bacteria. Experiments using absorbed sera showed that the protective antibodies are specific to outer membrane proteins. Thus, live-attenuated P. aeruginosa vaccines delivered nasally protect against corneal infections in mice and potentially can be used to prepare passive therapy reagents for the treatment of established P. aeruginosa corneal infections caused by diverse LPS serogroups.

A Comparison of Gatifloxacin to Ciprofloxacin in the Prophylaxis of Streptococcus pneumoniae in Rabbits in a LASIK Model

PURPOSE

To investigate the efficacy of the fourth-generation fluoroquinolone, gatifloxacin 0.3%, compared to ciprofloxacin 0.3%, in preventing Streptococcus pneumoniae keratitis in a rabbit laser in situ keratomileusis (LASIK) model.

METHODS

Twelve albino rabbits had bilateral lamellar flaps created. Group A (eight eyes) was given gatifloxacin 0.3%; group B (eight eyes) was given ciprofloxacin 0.3%; and group C (eight eyes) served as the controls. Groups A and B received one drop of antibiotic 20 minutes before the creation of the lamellar flap, at the conclusion of flap formation, and four times per day for 3 days. All corneas were inoculated with 0.1 mL of 4 x 10 organisms/mL of S. pneumoniae immediately after flap formation. On day 3, all corneas were examined and cultured.

RESULTS

Group A (gatifloxacin) had no infiltrates and three areas of 1-mm central corneal haze. On day 3, one of eight corneas had a positive culture. Group B (ciprofloxacin) had seven infiltrates, including one perforation, and six of eight corneas had positive cultures. Group C (control) had eight corneal infiltrates, and all eight corneas had positive cultures. The data show a statistically significant difference between gatifloxacin and ciprofloxacin and gatifloxacin and control for mean infiltrate size and mean culture scores.

CONCLUSIONS

The fourth-generation fluoroquinolone, topical gatifloxacin 0.3%, is superior to topical ciprofloxacin 0.3% for prophylaxis against a clinical isolate of S. pneumoniae in a rabbit LASIK model.

A Useful Augmented Lateral Tarsal Strip Tarsorrhaphy for Paralytic Ectropion

OBJECTIVE

Patients with paralytic ectropion and lagophthalmos may experience keratitis and may pose a functional and aesthetic surgical challenge. Various methods are used to reduce the vertical palpebral aperture, including lateral tarsal strip (LTS) or a lateral tarsorrhaphy. We modified the LTS to differentially shorten and elevate the lower lid more than the upper: an augmented LTS tarsorrhaphy (aug-LTS-T). This study aimed to evaluate the technique.

DESIGN

Prospective noncomparative surgical trial in which preoperative and postoperative symptoms, margin reflex distances, vertical palpebral aperture (PA), lagophthalmos, and corneal findings were recorded. The data were analyzed at 6 months after surgery using the Wilcoxon sign-rank test for nonparametric data.

PARTICIPANTS

Fourteen consecutive adult patients (15 eyelids) with chronic lagophthalmos and paralytic ectropion.

METHODS

Patients underwent aug-LTS-T. This consisted of a long strip (10-15 mm) that is attached to the outer temporal orbital rim, at a point higher than a conventional LTS. It included removal of a small part of the upper eyelid anterior lamella laterally to pass the long strip up high enough.

MAIN OUTCOME MEASURES

Improvement of symptoms, reduction of lower margin reflex distance, lagophthalmos, and improvement of corneal signs.

RESULTS

Minimum follow-up was 6 months. There was a significant reduction in PA (P = 0.005) and lagophthalmos (P = 0.0002) with improvement of corneal signs (14 of 15 eyelids = 93%). Surgery was successful anatomically in 14 of 15 eyelids (93%) with low morbidity.

CONCLUSIONS

We describe the augmented LTS tarsorrhaphy and find it effective in the treatment of severe lower eyelid ectropion resulting from facial palsy.

Survival of Pseudomonas aeruginosa in M-K preserved corneas

AIM

To present seven eyes of suspected donor to host transmitted Pseudomonas sp corneal graft infection after corneal and scleral graft leading to corneal melting within 24 hours, in a span of 10 months.

METHODS

Case series. Seven eyes, operated for either penetrating or lamellar keratoplasty or scleral patch graft for different indications and which developed massive corneal/corneoscleral infection within 24 hours, were studied prospectively.

RESULTS

Pseudomonas aeruginosa, resistant to almost all antibiotics except polymyxin B in all and vancomycin in two, was identified as the causative organism from all the specimens obtained from the infected graft.

CONCLUSION

Post-keratoplasty infection is a disaster. The source of early infection is invariably iatrogenic. Use of empirical antibiotics in the media is not always sufficient to prevent such infection. Thus, measures must be taken in the form of strict maintenance of asepsis and revision of antibiotics added to the storage medium. Further, early recognition and energetic therapy for such infection could reduce the ophthalmic morbidity.

Mikrobielle Keratitis nach Laser-in-situ-Keratomileusis

Laser in situ keratomileusis (LASIK) is an effective option and currently one of the most commonly applied surgical techniques in the correction of refractive errors such as myopia, hyperopia, and astigmatism. In contrast to photorefractive keratectomy, it maintains the integrity of Bowman's membrane and the epithelium leading to faster visual rehabilitation as well as less pain and discomfort. Nevertheless, following LASIK the stroma is exposed to infectious organisms. Sight-threatening complications after LASIK are reported to be as rare as 1 in 1000 procedures. However, any infectious keratitis remains potentially devastating. Reports about infectious keratitis following LASIK have increasingly surfaced in recent years. We present a review of the literature on microbial keratitis and present our own cases and recommendations for possible prophylaxis and therapy.

Use of Polymyxin as an Endotoxin Blocker in the Prevention of Diffuse Lamellar Keratitis in an Animal Model

PURPOSE

To determine whether bacterial endotoxin, lipopolysaccharide (LPS), could induce diffuse lamellar keratitis (DLK) in an animal model and whether DLK could be prevented by endotoxin blockers such as polymyxin.

METHODS

Laser in situ keratomileusis (LASIK) flaps were created in rabbit eyes. The stromal bed was treated with 20 microg of Burkholderia cepacia LPS or balanced salt solution (BSS). Development of DLK, histological degree of inflammation, and presence of LPS detected by anti-LPS antibody were evaluated after 48 hours. In a second experiment, all eyes received LPS and were randomly assigned to receive either polymyxin in the form of two drops of Polytrim (Allergan, Irvine, Calif) on the stromal bed or two drops of BSS.

RESULTS

In the animal model study, LPS was significantly associated with the development of DLK (P<.05, n=30). Infiltration with polymorphonuclear cells and presence of DLK were found in LPS treated eyes but not in controls. In the second experiment, 4 (27%) of 15 eyes that received polymyxin in addition to LPS developed DLK compared to 18 (95%) of 19 eyes that received only LPS (P<.05, n=34). There was a trend towards higher flap displacement in polymyxin treated eyes but this was not significant (P=.07).

CONCLUSIONS

Diffuse lamellar keratitis in a rabbit model can be caused by bacterial endotoxin (LPS). Endotoxin blockers, such as polymyxin, are effective in decreasing the incidence of endotoxin-induced DLK in a rabbit model.

Interleukin-1beta tear concentration in glaucomatous and ocular hypertensive patients treated with preservative-free nonselective beta-blockers

PURPOSE

To evaluate the ocular surface inflammatory response to the presence of preservatives in nonselective beta-blocker eyedrops.

DESIGN

Prospective, crossover, single-masked, randomized clinical study.

METHODS

study population: Twenty primary open-angle glaucoma or ocular hypertensive patients were divided in two groups, one treated with preservative-free timolol 0.5% (group 1) and the other with preserved timolol 0.5% (group 2) eyedrops. After 60 days of therapy and 3 more weeks of washout, the two groups switched to the other therapy. procedure: At each visit, basal tear samples were collected from the inferior conjunctival fornix for the determination of interleukin (IL)-1beta tear concentrations by an enzyme-linked immunosorbent assay. Intraocular pressure measurement, conjunctival hyperemia, superficial punctate keratitis, and tear film breakup time were evaluated. main outcome measure: IL-1beta concentration in tears following the use of preserved eyedrops.

RESULTS

IL-1beta tear concentrations increased significantly in both groups, compared with baseline values, during preserved timolol therapy. There were no statistically significant changes in hyperemia and superficial punctate keratitis throughout the study in either group. A statistically significant breakup time reduction was observed in both groups after 30 days and after 60 days of preserved therapy.

CONCLUSION

The use of preservatives in timolol 0.5% eyedrops leads to tear film instability and ocular surface inflammatory changes documented by a reduction of breakup time and an increase of IL-1beta tear concentrations. Preservative-free beta-blockers are preferable for long-term hypotensive therapy to prevent ocular surface inflammation.

Prevention of experimental diffuse lamellar keratitis using a novel platelet-activating factor receptor antagonist

PURPOSE

To determine whether a novel platelet-activating factor (PAF) antagonist prevents experimentally induced diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK).

SETTINGS

Department of Ophthalmology and Neuroscience Center of Excellence, Louisiana State University Health Science Center, New Orleans, Louisiana, USA.

METHODS

Twenty eyes of 10 New Zealand albino rabbits were used. The left eyes were treated with a peribulbar injection of 0.5 mL of PAF receptor antagonist LAU 0901 (2,4,6-trimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid ester) dissolved in 20 hydroxypropyl B cyclodextrin (30 microg /mL). Two rabbits were treated with a peribulbar injection of 0.5 mL of vehicle (cyclodextrin) alone and served as controls. A corneal flap was cut in all eyes, and the interface was exposed to Pseudomonas aeruginosa endotoxin. The left eyes were additionally treated with 1 drop of LAU 0901 4 times a day. Rabbits were killed on postoperative days 1, 2, 3, 5, and 8. The eyes were enucleated and processed for histopathology and immunohistochemical examination.

RESULTS

Corneas not treated with LAU 0901 and controls showed a severe inflammatory response in the flap margin and stromal interface, characterized by loss of keratocytes, activation of adjacent keratocytes and transformation to myofibroblasts, infiltration of polymorphonuclear leukocytes and monocytes, and presence of epithelial cells with necrosis and melting of adjacent stroma. Corneas of rabbits treated with LAU 0901 showed minimal loss of keratocytes and myofibroblast transformation, minimal inflammatory cell infiltration, and minimal presence of epithelial cells in the interface.

CONCLUSION

Induction of DLK was blocked by a PAF receptor antagonist in rabbit eyes. The histopathological evaluation and immunohistochemical studies showed that treatment with LAU 0901 blocked keratocyte apoptosis, transformation of fibroblasts to myofibroblasts and migration to the wound site, and chemotaxis of inflammatory cells, inhibiting the inflammatory response and promoting adequate healing of the flap interface and adjacent stroma.

Human corneal stromal tissue concentration after consecutive doses of topically applied 3.3% vancomycin

AIMS

To evaluate vancomycin penetration into human corneal stromal tissue in patients treated with topical vancomycin eyedrops before penetrating keratoplasty (PKP).

METHODS

Twenty four patients who underwent PKP, seven patients with keratoconus (group 1) and 17 patients with corneal scar or corneal decompensation (group 2). All patients received topical application of vancomycin eyedrops (concentration: 33 mg/ml) 10, 3, 2, 1 hour, and 15 minutes before the operation. Corneal cumulative vancomycin levels were assessed by bioassay.

RESULTS

Mean vancomycin corneal stromal tissue concentration was 46.7 (SE 4.11) microg/g tissue. This value was four to 20-fold in excess of the MIC90 of vancomycin in Staphylococcus aureus (2-10 microg/ml).

CONCLUSIONS

Vancomycin reached high corneal tissue concentrations that significantly exceeded the MIC90 (2-10 microg/ml) for most key Gram positive corneal pathogens. The ratio of vancomycin stromal concentration to protein concentration was statistically higher in group 2 (non-keratoconus).

Ultraviolet Eye Radiation: The Problem and Solutions

Ultraviolet radiation (UVR) can cause damage to the eyes. Some of the damage is acute, with immediate signs and symptoms, while some of the damage is the result of cumulative or long-term UVR exposure. Because the most common source of UVR is the sun, individuals who are exposed to sunny environments should be advised to protect themselves properly. Individuals should be counseled about proper eye protection from UVR in sunlight. It is important to know when eye protection is indicated. Protection involves wearing a wide-brimmed hat or cap and well-designed sunglasses. The advisable sunglass features include the following: large eye size with side protection, less than 1% UV-B transmittance, less than 1% UV-A transmittance, gray or near-neutral colored lenses, good optical quality, and visible transmittance selected for visual comfort. Some clear spectacles or contact lenses also provide good levels of UV protection. When selecting sunglasses, it is always helpful to consult your eye care specialist.

Evaluation of preoperative and postoperative prophylactic regimens for prevention and treatment of diffuse lamellar keratitis

PURPOSE

To investigate preoperative and postoperative prophylactic treatment with different pharmacological agents before flap cutting and exposure to a diffuse lamellar keratitis (DLK) causative agent.

SETTING

Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

The study comprised 48 eyes of 24 Dutch-belted rabbits. Three days before a corneal flap was cut and the corneal interface was exposed to Pseudomonas aeruginosa lipopolysaccharide endotoxin, a DLK causative agent, the eyes were randomly assigned to treatment with a mast-cell stabilizer, a nonsteroidal antiinflammatory drug (NSAID), or a corticosteroid or left without treatment as controls. The treatment was maintained throughout the 1-week follow-up. Slitlamp examinations and photographs were performed at 1, 3, 5, and 7 days; DLK was graded by a masked observer from 0 (no DLK) to IV. Corneal interface scrapings were performed in selected eyes on day 7.

RESULTS

At the end of the follow-up, 36 eyes were available for evaluation. At 1 week, 100% of the control eyes and the eyes treated with the mast-cell stabilizer developed DLK; in the NSAID-treated and corticosteroid-treated eyes, the DLK rate was 86% and 70%, respectively. At 1 day, the severity of DLK was significantly lower in eyes treated with the mast-cell stabilizer (0.44) and at 7 days, it was significantly lower in corticosteroid-treated eyes (0.3) than in the control group (1.5 and 1.4, respectively) (P<.05, Wilcoxon test). Corneal interface scraping from an eye with grade III DLK showed numerous inflammatory cells.

CONCLUSIONS

Preoperative and postoperative treatment with corticosteroids significantly reduced the severity of DLK compared to the untreated control eyes in this animal model. Treatment with a mast-cell stabilizer and an NSAID had less effect on the postoperative course of DLK.

Wiping microkeratome blades with sterile 100% alcohol to prevent diffuse lamellar keratitis after laser in situ keratomileusis

PURPOSE

To report our experience in preventing diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) by wiping the microkeratome blade with sterile 100% alcohol.

SETTING

Enaim Refractive Surgery Center, Jerusalem, Israel.

METHODS

Laser in situ keratomileusis was performed in 24 patients (48 eyes) on the same day by the same surgeon. The environment and instruments were identical in all cases. A new blade was used in both eyes of each patient. All blades were from the same batch and were randomly assigned to 2 groups. In the alcohol group, 12 blades were wiped with a Merocel surgical spear (Medtronic Solan) dipped in 100% alcohol and rinsed with balanced salt solution (BSS) before they were mounted in a Hansatome microkeratome (Bausch & Lomb Co.); in the control group, 12 blades were wiped with a Merocel surgical spear dipped in BSS and rinsed with BSS. All patients were examined on the first postoperative day.

RESULTS

Grade I to II DLK was diagnosed in 7 eyes of 4 patients in the control group (29%). No DLK was diagnosed in the alcohol group.

CONCLUSION

Wiping the microkeratome blade with 100% alcohol before mounting may remove a substance from the manufacturing or sterilization process that can cause DLK.