SARS-CoV-2 infection status in corneal preservation solution and COVID-19 prevalence after corneal transplantation.

The potential risks associated with organs from COVID-19-infected donors were unclear. To determine the SARS-CoV-2 infection status of corneas transplanted during the COVID-19 pandemic, we performed a polymerase chain reaction (PCR) using the corneal preservation solution that was used for corneal transplantation. We also examined the postoperative health status of the recipients. This study included 144 transplants in 143 eyes. Ninety-nine eyes of imported corneas and 10 of the 14 corneas donated in the prefecture were PCR tested at our hospital, and all were SARS-CoV-2 negative. All corneal transplants were performed after confirming their SARS-CoV-2 negativity by a PCR using a corneal preservation solution at our hospital or a nasopharyngeal swab at a previous facility. Despite postoperative steroid administration, no patient developed COVID-19 infection until discharge. Hence, if the donor's nasopharyngeal swab test is SARS-CoV-2 negative, COVID-19 infection in the recipient due to corneal transplantation may be prevented. Since corneal transplant recipients are susceptible to infection due to prolonged steroid administration and are at high risk for severe diseases if infection occurs, SARS-CoV-2 detection testing using nasopharyngeal swabs in donors should be performed.

Efficacy of ripasudil in reducing intraocular pressure and medication score for ocular hypertension with inflammation and corticosteroid.

AIM: To investigate the efficacy of ripasudil, a Rho kinase inhibitor, in reducing intraocular pressure (IOP) and medication scores of anti-glaucoma drugs in patients with ocular hypertension with inflammation and corticosteroid. METHODS: The study included 11 patients diagnosed with ocular hypertension with inflammation and corticosteroid, all of whom were prescribed ripasudil eye drops and followed up for at least 2y after the initiation of treatment. IOP was measured using a non-contact tonometer before enrollment and at each follow-up visit. The medication score of glaucoma eye drops was calculated for each patient. RESULTS: The mean IOP (26.4±2.9 mm Hg before treatment) significantly decreased after ripasudil therapy (13.7±3.3 mm Hg at 3mo) and remained stable in the low-teens during the 2-year follow-up period (P<0.0001). A significant decrease in the medication score was observed at 12mo or later after the initiation of ripasudil therapy (P<0.05). Both baseline medication scores and glaucomatous optic disc change rates were significantly higher in the five eyes that required glaucoma surgery during the 2-year observation period than the 10 eyes that did not require surgery. CONCLUSION: Our results demonstrate the efficacy of ripasudil, in reducing IOP and the medication score over a 2-year treatment period in patients with ocular hypertension with inflammation and corticosteroid. Our findings also suggest that ripasudil could reduce the IOP in uveitic glaucoma patients with both lower baseline medication score and lower glaucomatous optic disc change rate.

Benzalkonium chloride-induced myofibroblastic transdifferentiation of Tenon's capsule fibroblasts is inhibited by coculture with corneal epithelial cells or by interleukin-10.

Benzalkonium chloride (BAC) is used as a preservative in eyedrops but induces subconjunctival fibrosis that can result in failure of glaucoma surgery. Tenon's capsule fibroblasts in subconjunctival tissue interact with the corneal epithelium through tear fluid. With the use of a coculture system, we have now investigated the effect of human corneal epithelial (HCE) cells on myofibroblastic transdifferentiation of human Tenon fibroblasts (HTFs) induced by BAC (5 × 10-6%). Immunofluorescence and immunoblot analyses revealed that the BAC-induced expression of α smooth muscle actin (αSMA) in HTFs was suppressed by coculture of these cells with HCE cells (p < 0.01). The concentration of interleukin-10 (IL-10) in culture supernatants of BAC-treated HTFs was increased by coculture with HCE cells (17.26-fold, vs. coculure, p < 0.001). Immunofluorescence and immunoblot analyses also showed that exogenous IL-10 (300 pg/ml) suppressed the BAC-induced expression of αSMA by 43.65% (p < 0.05) as well as the nuclear translocation of myocardin-related transcription factor-A (MRTF-A) by 39.32% (p < 0.01) in HTFs cultured alone. Our findings suggest that corneal epithelial cells may protect against subconjunctival fibrosis by maintaining IL-10 levels and preventing the MRTF-A-dependent transdifferentiation of HTFs into myofibroblasts.

Influence of extended depth of focus intraocular lenses on visual field sensitivity.

PURPOSE: To investigate the influence of EDOF IOLs, TECNIS Symfony® (Johnson & Johnson Surgical Vision, Inc.), on visual field sensitivity and to compare the IOLs with other kinds of IOLs. METHODS: The subjects included the normal fellow eyes of patients who underwent the Humphrey Field Analyzer (HFA) 30-2 with Swedish Interactive Threshold Algorithm Fast within 6 months after cataract due to glaucoma or suspected glaucoma. Each parameter of HFA was compared among eyes implanted with TENIS Symfony® (EDOF group), diffractive bifocal IOLs (bifocal group), and monofocal IOLs (monofocal group). RESULTS: The total of 76 eyes, including 24 eyes in the EDOF group, 26 eyes in the bifocal group, and 26 eyes in the monofocal group, were included in this study. Mean deviation (MD) of HFA was -0.24±0.58 dB in the EDOF group, -1.38±0.58 dB in the bifocal group, and 0.02±0.44 dB in the monofocal group. Foveal threshold (FT) of HFA was 35.8±1.6 dB in the EDOF group, 33.6±1.7 dB in the bifocal group, and 36.6±1.4 dB in the monofocal group. In both MD and FT, there was significant difference between the bifocal group and the others (p<0.001). There was no difference between the EDOF group and the monofocal group. Moreover, there was no significant difference between the three groups about pattern standard deviation (PSD) of HFA. CONCLUSION: TECNIS Symfony® may have little influence on visual field sensitivity, whereas diffractive bifocal IOLs decrease visual field sensitivity.

Simultaneous Vitreoretinal Surgery and Penetrating Keratoplasty without a Keratoprosthesis or Endoscopy for Vitreoretinal Disease Associated with Corneal Opacity.

We evaluated the visual outcome of combined penetrating keratoplasty (PKP) and 25G pars plana vitrectomy (PPV) performed without a temporary keratoprosthesis or endoscopy in a patient with vitreoretinal disease complicated by severe corneal opacity. The patient was a 68-year-old woman who had severe corneal opacity and silicone oil in her left eye after several previous intraocular surgeries for rhegmatogenous retinal detachment and proliferative vitreoretinopathy. We successfully performed a combined surgery of conventional PKP followed by 25G PPV without the use of a keratoprosthesis. At 6 months after surgery, visual acuity had not improved, and the density of corneal endothelial cells of the donor cornea had declined from 3,205 to 1,969 cells/mm2. However, corneal transparency remained good, and additional surgery for vitreoretinal disease was not necessary. The combined surgical procedure designed to minimize the number of open-sky steps and to limit vitreoretinal complications thus proved to be safe and achieved stable corneal clarity in a patient with vitreoretinal disease and severe corneal opacity.

Combination management by C-arm fluoroscopy and extraocular muscle severance for penetrating ocular trauma with a retrobulbar foreign body.

We report here the successful removal of a retrobulbar metallic foreign body in a patient with penetrating ocular trauma by a transconjunctival approach and combination management with C-arm fluoroscopy and extraocular muscle severance. A 37-year-old man sustained a penetrating injury to the right eye while using an iron hammer. Initial slitlamp examination revealed a corneoscleral laceration, iridocele, anterior chamber collapse, and a traumatic cataract. Visual acuity in the right eye was limited to the perception of hand motion. Computed tomography revealed an orbital foreign body in the retrobulbar area. The patient underwent corneoscleral suturing, severance of extraocular muscles, removal of the foreign body with guidance by C-arm fluoroscopy, pars plana lensectomy, and pars plana vitrectomy. Combination management with C-arm fluoroscopy and extraocular muscle severance may thus be a suitable approach to the removal of a retrobulbar metallic foreign body.

Comparison of the toxicity profile of benzalkonium chloride-preserved tafluprost and SofZia-preserved travoprost applied to the ocular surface.

PURPOSE: To evaluate some clinically important features of benzalkonium chloride (BAK) toxicity by comparing tafluprost with 0.001% BAK and travoprost preserved with SofZia applied to the ocular surface of the eyes with glaucoma. METHODS: This was a prospective, randomized, observer unmasked, multicenter crossover trial. A total of 195 patients were randomized and 174 patients completed the study at 19 clinics between November 2011 and August 2012. Topical BAK-preserved tafluprost or SofZia-preserved travoprost was newly administered or continued. Superficial punctate keratopathy (SPK), tear break-up time (BUT), the conjunctival hyperemia score, and intraocular pressure (IOP) were compared at the baseline visit, 4, and 12 weeks after the start of therapy. The eye drops were switched to another eye drop after 12 weeks of observation. RESULTS: The total SPK and conjunctival hyperemia scores were significantly lower in the tafluprost compared with those in the travoprost phase (both P=0.038). There were no significant differences in the SPK scores of the superior area (P=0.679), central area (P=0.089), inferior area (P=0.090), and tear BUT (P=0.271). The IOP-lowering effects were similar (P=0.155). CONCLUSIONS: SPK, hyperemia score, and tear BUT while using tafluprost with 0.001% BAK were not inferior compared with those caused by travoprost with SofZia.

All-trans-retinoic acid inhibition of transforming growth factor-ß-induced collagen gel contraction mediated by human Tenon fibroblasts: role of matrix metalloproteinases.

BACKGROUND/AIMS: Scarring and contraction of the conjunctiva are common complications of many ocular diseases. We investigated the effects of all-trans-retinoic acid (ATRA) on the contractility of human Tenon's capsule fibroblasts (HTFs) cultured in a three-dimensional collagen gel. METHODS: HTFs were cultured in a three-dimensional gel of type I collagen and in the absence or presence of transforming growth factor (TGF)-ß, ATRA, or an inhibitor of matrix metalloproteinases (MMPs). Collagen gel contraction was evaluated by measurement of gel diameter. The release of MMPs and tissue inhibitors of metalloproteinases (TIMPs) into culture supernatants was assessed by immunoblot analysis and gelatin zymography. The release of lactate dehydrogenase activity from HTFs was measured with a colorimetric assay kit. RESULTS: ATRA inhibited TGF-ß-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. TGF-ß induced the release of MMP-1, MMP-2 and MMP-3 by HTFs, and ATRA inhibited these effects of TGF-ß on MMP-1 and MMP-3 release. ATRA also stimulated TIMP-1 release from HTFs in the presence of TGF-ß. Furthermore, TGF-ß-induced collagen gel contraction was blocked by the MMP inhibitor GM6001. ATRA did not exhibit cytotoxicity for HTFs. CONCLUSIONS: ATRA inhibited TGF-ß-induced collagen gel contraction mediated by HTFs, likely in part by attenuating the production of MMP-1 and MMP-3 and by stimulating the production of TIMP-1. ATRA may therefore prove to be of clinical value for inhibition of scar formation in the conjunctiva.

Inhibition by a retinoic acid receptor γ agonist of extracellular matrix remodeling mediated by human Tenon fibroblasts.

PURPOSE: Scar formation is most frequently responsible for the failure of glaucoma filtration surgery. Retinoic acids are vitamin A derivatives that play diverse roles in development, immunity, and tissue repair. The effects of the retinoic acid receptor (RAR) γ agonist R667 on the contractility of human Tenon fibroblasts (HTFs) cultured in a three-dimensional collagen gel as well as on intraocular pressure (IOP) in a rat model of glaucoma filtration surgery were investigated. METHODS: HTFs were cultured in a type I collagen gel, the contraction of which was evaluated by measurement of the gel diameter. The release of matrix metalloproteinases (MMPs) into culture supernatants was assessed with immunoblot analysis and gelatin zymography. Phosphorylation of focal adhesion kinase (FAK) was examined with immunoblot analysis, and production of fibronectin and type I collagen was measured with immunoassays. RESULTS: R667 inhibited transforming growth factor-ß1 (TGF-ß1)-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner, whereas an RARα agonist inhibited this process to a lesser extent and an RARß agonist had no effect. TGF-ß1-induced MMP-1 and MMP-3 release, FAK phosphorylation, and fibronectin and type I collagen production in HTFs were also attenuated by R667. Furthermore, R667 lowered IOP in rats after glaucoma filtration surgery. CONCLUSIONS: R667 inhibited TGF-ß1-induced contraction and extracellular matrix synthesis in HTFs. Such effects might have contributed to the lowering of IOP by R667 in a rat model of glaucoma filtration surgery. RARγ agonists might thus prove effective for inhibition of scar formation after such surgery.

Safety and Efficacy of Benzalkonium Chloride-optimized Tafluprost in Japanese Glaucoma Patients With Existing Superficial Punctate Keratitis.

PURPOSE: To evaluate the safety and efficacy of benzalkonium chloride (BAK)-optimized tafluprost (with a BAK concentration reduced from 0.01% to 0.001%) in glaucoma patients with existing superficial punctate keratitis (SPK). PATIENTS AND METHODS: A prospective, multicenter, open-label study was designed to compare BAK-optimized tafluprost administered over 12 weeks relative to other preserved prostaglandin analogs previously administered in Japanese glaucoma patients. Thirty patients with SPK graded at <6 points by area density (AD) scoring in 1 eye were recruited. The primary outcome measure was change in AD score at 12 weeks after the switch in treatment compared with that at baseline. Secondary outcome measures included changes in tear film breakup time (TBUT), hyperemia score, and intraocular pressure (IOP). Four patients were excluded from analysis because of treatment discontinuation. RESULTS: Mean AD score±SD decreased significantly from 3.4±0.9 to 1.8±1.8 after the switch (P<0.0001). Mean TBUT increased significantly from 6.3±3.3 to 8.0±4.2 seconds (P<0.01). Mean hyperemia score remained unchanged, whereas mean IOP decreased significantly from 15.6±2.6 to 14.4±2.0 mm Hg (P<0.01). For patients previously treated with BAK-preserved latanoprost (n=17) or bimatoprost (n=2), mean AD score decreased significantly from 3.4±0.9 to 1.8±1.8 (P<0.01) and mean TBUT increased significantly from 6.4±3.6 to 8.2±4.3 seconds (P<0.01); no such changes were apparent for patients previously treated with sofZia-preserved travoprost (n=7). CONCLUSIONS: BAK-optimized tafluprost is a treatment option to improve the condition of the ocular surface and to maintain IOP control in glaucoma patients with existing SPK who have been previously treated with other BAK-preserved prostaglandin analogs.

Inhibition by all-trans-retinoic acid of transforming growth factor-ß-induced collagen gel contraction mediated by human tenon fibroblasts.

PURPOSE: Excessive wound contraction can lead to scar formation in the conjunctiva. The effects of all-trans-retinoic acid (ATRA) on the contractility of human Tenon fibroblasts (HTFs) cultured in three-dimensional (3D) collagen gels were investigated. METHODS: Human Tenon fibroblasts were cultured in 3D gels of type I collagen and in the absence or presence of TGF-ß, ATRA, or various inhibitors. Collagen gel contraction was evaluated by measurement of gel diameter. Phosphorylation of various signaling molecules was examined by immunoblot analysis. The formation of actin stress fibers and focal adhesions was detected by laser confocal microscopy. RESULTS: All-trans-retinoic acid inhibited TGF-ß-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. The TGF-ß-induced phosphorylation of focal adhesion kinase (FAK) and formation of stress fibers and focal adhesions in HTFs were attenuated by ATRA. All-trans-retinoic acid also inhibited the TGF-ß-induced phosphorylation of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase (ERK), p38, and c-Jun NH2-terminal kinase (JNK) as well as that of c-Jun and Smad2/3. Furthermore, TGF-ß-induced collagen gel contraction was blocked by inhibitors of ERK, p38, or JNK signaling. CONCLUSIONS: All-trans-retinoic acid inhibited TGF-ß-induced collagen gel contraction mediated by HTFs, most likely by attenuating the formation of actin stress fibers and focal adhesions as well as signaling by MAPKs, c-Jun, and Smads. All-trans-retinoic acid may therefore prove effective for inhibition of conjunctival scarring through attenuation of the contractility of Tenon fibroblasts.

Protective effect of dexamethasone against hypoxia-induced disruption of barrier function in human corneal epithelial cells.

The corneal epithelium functions as a barrier to protect the cornea from external agents such as infectious organisms and toxins and thereby contributes to corneal homeostasis. The barrier function of epithelia is dependent on the formation of tight and adherens junctions between adjacent epithelial cells. We have previously shown that hypoxia disrupts the barrier function of cultured human corneal epithelial (HCE) cells by affecting tight junctions. We have now examined the effect of dexamethasone on this barrier disruption induced by hypoxia in HCE cells. Measurement of transepithelial electrical resistance revealed that the hypoxia-induced decrease in the barrier function of HCE cells was inhibited by dexamethasone in a concentration-dependent manner. The hypoxia-induced loss of the tight junction protein ZO-1 from the borders of adjacent HCE cells (as revealed by immunofluorescence analysis) as well as the hypoxia-induced down-regulation of ZO-1 expression (as revealed by immunoblot analysis) were also inhibited by dexamethasone, whereas this drug had no effect on the expression or distribution of the tight junction protein occludin or of the adherens junction proteins E-cadherin and ß-catenin. Moreover, dexamethasone attenuated the reorganization of the actin cytoskeleton, the formation of focal adhesions, and the up-regulation of myosin light chain kinase expression induced by hypoxia in HCE cells. Our results thus suggest that dexamethasone protects corneal epithelial cells from the hypoxia-induced disruption of barrier function by maintaining the distribution and expression of ZO-1 as well as the organization of the actin cytoskeleton.

Role of ß-Pix in corneal epithelial cell migration on fibronectin.

PURPOSE: Corneal epithelial migration during wound healing is important for maintenance of corneal transparency, and fibronectin plays a key role in regulation of the adhesion and migration of corneal epithelial cells. The role of ß-Pix in intracellular signaling that underlies the stimulatory effects of fibronectin on the adhesion and migration of corneal epithelial cells was examined. METHODS: Simian virus 40-transformed human corneal epithelial (HCE) cells were cultured on fibronectin or on bovine serum albumin as a control. The localization and tyrosine phosphorylation of ß-Pix were examined by immunofluorescence and immunoprecipitation analyses, respectively. The actin cytoskeleton and focal adhesions were detected by staining of cells with rhodamine-phalloidin and antibodies to phosphotyrosine, respectively. The effects of depletion of ß-Pix on HCE cell adhesion and migration on fibronectin were investigated by cell transfection with a small interfering RNA specific for ß-Pix mRNA. RESULTS: Fibronectin induced the tyrosine phosphorylation of ß-Pix as well as its apparent accumulation at focal adhesions in HCE cells. Depletion of ß-Pix inhibited the effects of fibronectin on remodeling of the actin cytoskeleton and the formation of focal adhesions. It also inhibited the migration of HCE cells on fibronectin in an in vitro model of wound healing, but it did not affect cell adhesion to fibronectin. CONCLUSIONS: ß-Pix contributes to the regulation of the formation of focal adhesions as well as that of cell migration by fibronectin in HCE cells. This protein therefore likely plays an important role in signal transduction underlying corneal epithelial wound healing.

Protection of human corneal epithelial cells from hypoxia-induced disruption of barrier function by hepatocyte growth factor.

The barrier function of the corneal epithelium maintains corneal homeostasis and is mediated by tight junctions (TJs) and adherens junctions (AJs). It is also susceptible to disruption by hypoxia. We have now examined the effects of hypoxia on TJs and AJs as well as on barrier function in human corneal epithelial (HCE) cells. Moreover, we investigated whether such effects of hypoxia might be modulated by hepatocyte growth factor (HGF). The subcellular distribution of the TJ proteins ZO-1 and occludin, the AJ proteins E-cadherin and beta-catenin, and actin filaments was examined by fluorescence microscopy. The abundance of junctional proteins as well as of myosin light chain kinase (MLCK) was determined by immunoblot analysis. Barrier function was evaluated by measurement of transepithelial electrical resistance (TER). Hypoxia-induced both the disappearance of ZO-1 from the borders of neighboring HCE cells as well as the down-regulation of ZO-1 expression without affecting the distribution or abundance of occludin, E-cadherin, or beta-catenin. It also induced the formation of actin stress fibers, the up-regulation of MLCK expression, and a reduction in the TER of HCE cells. All these effects of hypoxia were inhibited by HGF. Neither hypoxia nor HGF exhibited a mitogenic or cytotoxic effect on HCE cells. HGF thus protects HCE cells from hypoxia-induced disruption of barrier function by maintaining the expression and distribution of ZO-1. Inhibition of the effects of hypoxia on the organization of the actin cytoskeleton might also contribute to this protective action of HGF.

Establishment of human corneal epithelial cells stably expressing human connexin43.

Corneal epithelial cells communicate with each other through gap junctions. Whereas this property is retained in corneal epithelial cells in primary culture, it is often lost in immortalized epithelial cells. However, the life span of primary cultured corneal epithelial cells is short and the availability of human tissue for their preparation is limited. To examine the role of the gap-junction protein connexin43 (Cx43) in human corneal epithelial cells, we set out to establish an immortal human corneal epithelial cell line that stably expresses this protein. An expression vector encoding human Cx43 fused to enhanced green fluorescent protein (EGFP) was constructed and introduced by transfection into SV40-immortalized human corneal epithelial (HCE) cells. Stable transfectants were isolated by selection with the antibiotic G418. The expression and localization of the Cx43-EGFP fusion protein were examined by immunoblot analysis and fluorescence microscopy, respectively, and gap-junctional intercellular communication was monitored on the basis of dye coupling. HCE cells stably expressing Cx43-EGFP manifested intercellular dye transfer, whereas those stably expressing EGFP alone did not. Cx43-EGFP localized to the interfaces of neighboring cells. Stable expression of Cx43-EGFP in HCE cells did not affect the expression of keratins 3 and 12, which is a characteristic of corneal epithelial cells, but it did inhibit cell proliferation. We have established an HCE cell line that stably expresses human Cx43 and forms functional gap junctions. These cells may prove useful for studies of the role of gap junctions in the human corneal epithelium.

Role of formation of an ERK-FAK-paxillin complex in migration of human corneal epithelial cells during wound closure in vitro.

PURPOSE: Migration of corneal epithelial cells is an important step in the corneal wound healing. The role of extracellular signal regulated kinase (ERK) for the regulation of cell migration during wound closure was examined. METHODS: Scratch wounds were introduced into human corneal epithelial cells in the absence or presence of PD98059, an ERK signaling inhibitor. The phosphorylation and localization of ERK during wound closure were examined by immunoblot and immunofluorescence analyses. The tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin, as well as the association of FAK with paxillin and ERK, were evaluated by immunoprecipitation and immunoblot analysis. The effect of a mutant form of MEK1 on cell migration and proliferation was determined by transfection. RESULTS: PD98059 inhibited cell migration in a concentration- and time-dependent manner. Wounding increased the phosphorylation of ERK as well as the tyrosine phosphorylation of FAK and paxillin in a manner sensitive to PD98059. Furthermore, wounding induced the formation of an ERK-FAK-paxillin complex and this effect as well as the wounding-induced formation of focal adhesions, membrane ruffles, and bundles of F-actin, were inhibited by PD98059. Phosphorylated ERK localized at the wound margin, and such localization was not observed in the presence of PD98059. Expression of dominant negative mutant form of MEK1 inhibited cell migration during wound closure without the effect of cell proliferation. CONCLUSIONS: ERK regulates cell migration during wound healing in vitro by modulating the phosphorylation of FAK and paxillin and the consequent formation of focal adhesions. An ERK-FAK-paxillin signaling pathway may play an important role in corneal epithelial wound healing in vivo.

[Effect of preservative-free betamethasone sodium phosphate eyedrops on the development of corneal epithelial disorders after penetrating keratoplasty].

PURPOSE: To investigate the effects of preservative-free eyedrops containing betamethasone sodium phosphate (BSP) on the development of corneal epithelial disorders after penetrating keratoplasty (PKP). METHODS: The records of 48 patients who underwent unilateral PKP and were followed for 6 months postoperatively were reviewed retrospectively. Twenty-four patients were treated with BSP eyedrops containing preservatives and the other 24 patients with preservative-free BSP eyedrops four times daily. Patients in the two groups were matched for age and sex. Corneal epithelial disorders and other complications were examined with a slitlamp biomicroscope at 1, 3, and 6 months after surgery. RESULTS: None of the patients developed corneal erosion or corneal epithelial defects. The incidence of superficial punctate keratopathy in the preservative-free group (2 of 24 eyes) was significantly reduced compared with that in the preservative group (9 of 24 eyes) 1 month after surgery. The SPK score in the preservative-free group (0.17 +/- 0.56 points) was also significantly smaller than that in the preservative group (1.04 +/- 1.46 points) at 1 month. There was no significant difference in other postoperative complications between the two groups. CONCLUSIONS: Preservative-free BSP eyedrops are effective for preventing the development of corneal epithelial disorders after PKP.

Detection of subepithelial fibrosis associated with corneal stromal edema by second harmonic generation imaging microscopy.

PURPOSE: Human corneas with or without stromal edema were examined by second harmonic generation (SHG) imaging microscopy to characterize stromal collagen organization. METHODS: Tissue buttons from 31 corneas with stromal edema and 8 normal corneas were fixed, and 3-mm(2) blocks were cut and stained with phalloidin, to visualize the cytoskeleton. The blocks were examined by SHG imaging with a laser confocal microscope and a mode-locked titanium:sapphire femtosecond laser. Samples were scanned to a depth of 150 microm from the surface of Bowman's layer, and SHG forward- and backscatter signals were collected. Phalloidin staining was detected by conventional laser confocal microscopy. The three-dimensional structure of the anterior segment of the cornea was reconstructed from stacked SHG images. RESULTS: Three-dimensional reconstruction of SHG signals showed adherence of interwoven collagen lamellae in the anterior stroma to Bowman's layer in both normal and edematous corneas. Abnormal SHG signals at the level of Bowman's layer were observed in edematous corneas; three-dimensional images revealed that these signals were actually localized above Bowman's layer and were indicative of subepithelial fibrosis. Phalloidin staining showed transdifferentiation of stromal cells into fibroblastic cells in edematous corneas. The incidence of subepithelial fibrosis or of fibroblastic cells increased beginning 12 months after the onset of clinical stromal edema. CONCLUSIONS: SHG imaging of the anterior segment of edematous corneas revealed a normal appearance of interwoven collagen lamellae in the anterior stroma. The development of subepithelial fibrosis beginning 12 months after the onset of edema suggests that stromal edema may be a progressive disease.

Interleukin-1beta-induced disruption of barrier function in cultured human corneal epithelial cells.

PURPOSE: The barrier function of the corneal epithelium contributes to corneal homeostasis and is impaired by inflammation. Adherens junctions (AJs) and tight junctions (TJs) of the corneal epithelium are essential for cell adhesion and barrier function. We examined the effects of the proinflammatory cytokine interleukin (IL)-1beta on AJs and TJs as well as on barrier function in simian virus 40-transformed human corneal epithelial (HCE) cells. METHODS: Barrier function was evaluated by measurement of transepithelial electrical resistance (TER). The subcellular distributions of the AJ proteins E-cadherin and beta-catenin, the TJ proteins ZO-1 and occludin, and the p65 subunit of nuclear factor (NF)-kappaB were determined by immunofluorescence staining. The expression of junctional proteins as well as the phosphorylation and degradation of the NF-kappaB-inhibitory protein IkappaB-alpha were examined by immunoblot analysis. RESULTS: IL-1beta induced the disappearance of ZO-1 and occludin from the interfaces of neighboring HCE cells without affecting the localization of E-cadherin or beta-catenin. It also reduced the TER of HCE cells in a concentration- and time-dependent manner. The overall abundance of TJ and AJ proteins was not affected by IL-1beta. IL-1beta induced the phosphorylation and downregulation of IkappaB-alpha as well as the translocation of p65 to the nucleus. The NF-kappaB inhibitor curcumin blocked the effects of IL-1beta on both TER and the subcellular localization of ZO-1 and occludin. CONCLUSIONS: IL-1beta induced the redistribution of ZO-1 and occludin from TJs of HCE cells and thereby disrupted the barrier function of these cells in a manner dependent on NF-kappaB. These effects of IL-1beta may contribute to the loss of corneal epithelial barrier function associated with ocular inflammation.