Toll-like receptor 4 signalling attenuates experimental allergic conjunctivitis.

Allergic conjunctivitis from an allergen-driven T helper type 2 (Th2) response is characterized by conjunctival eosinophilic infiltration. Association between signalling through Toll-like receptor 4 (TLR-4) and adaptive immune responses has been observed in allergic airway disease. We examined whether administration of bacterial lipopolysaccharide (LPS), a prototypic bacterial product that activates immune cells via TLR-4, could affect the development of allergic conjunctivitis and modify the immune response to ovalbumin (OVA) allergen in an experimental allergic conjunctivitis (EAC) model. Mice were challenged with two doses of OVA via conjunctival sac after systemic challenge with OVA in alum. Several indicators for allergy were evaluated in wild-type and TLR-4(-/-) mice with or without adding of different doses of LPS into OVA in alum. Mice challenged with OVA via conjunctival sac following systemic challenge with OVA in alum had severe allergic conjunctivitis. Of interest, LPS administration markedly suppressed immunoglobulin (Ig)E-mediated and eosinophil-dependent conjunctival inflammation. In addition, mice sensitized with OVA plus LPS had less interleukin (IL)-4, IL-5 and eotaxin secretion than mice sensitized with OVA only. The suppression of allergic response by LPS administration was due to Th1 shift. In contrast, the presence of LPS during sensitization with OVA had no effect on severity of allergic conjunctivitis and Th2 responses in TLR4-4(-/-) mice. Our findings demonstrate, for the first time, that LPS suppresses Th2 responses via the TLR-4-dependent pathway in the EAC model.

Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water.

In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chilseo Water Treatment Plant (CWTP) situated in Haman, Korea as well as the effluents from sand and granular activated carbon (GAC) filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting (FRA and SRA) organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products (DBPs). If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

Association of -31T>C and -511 C>T polymorphisms in the interleukin 1 beta (IL1B) promoter in Korean keratoconus patients.

PURPOSE: To investigate the genetic association between unrelated Korean keratoconus patients and interleukin 1 alpha (IL1A), interleukin 1 beta (IL1B), and IL1 receptor antagonist (IL1RN) gene polymorphisms. METHODS: We investigated the association between IL1A (rs1800587, rs2071376, and rs17561), IL1B (rs1143627, rs16944, rs1143634, and rs1143633), and IL1RN (rs419598, rs423904, rs424078, and rs315952, variable number tandem repeat [VNTR]) polymorphisms in 100 unrelated Korean keratoconus patients. One hundred control individuals without any corneal disease were selected from the general population. Polymerase chain reaction (PCR) - restriction fragment length polymorphism (RFLP) analysis and direct sequencing were used to screen for genetic variations in the IL1 gene cluster. Haplotypes for the IL1 gene cluster were constructed using Haploview version 4.0. RESULTS: We analyzed a total of 12 polymorphic sites in the IL1 gene cluster. Among them, the -511 (rs16944) and -31 (rs1143627) positions in the promoter region of IL1B were significantly different between patient and control groups. The C allele of rs16944 (-511C>T, p=0.022, odds ratio of risk [OR]=1.46, 95% confidence intervals [CI] 0.94<2.27) and the T allele of rs1143627 (-31T>C, p=0.025, OR=1.43, 95% CI 0.92<2.22) were associated with a significantly increased risk of keratoconus in Korean patients. Linkage of the two alleles, -31*C and -511*T, was associated with an increased risk for keratoconus with OR=2.38 (p=0.012, 95% CI=1.116-5.046). The *C/*A genotype of rs2071376 in IL1A intron 6 was significantly different between the keratoconus patients and control subjects (p=0.034, OR=0.59, 95% CI 0.32<1.11). Other polymorphisms did not show an association with keratoconus risk. CONCLUSIONS: This is the first report of IL1 gene cluster mutation screening in Korean keratoconus patients. Significant differences in allelic frequency of IL1B between keratoconus patients and the control group suggest that IL1B polymorphisms may play a role in the susceptibility of unrelated Koreans to develop keratoconus.

Comparison of clinical results between heparin surface modified hydrophilic acrylic and hydrophobic acrylic intraocular lens.

PURPOSE: To compare the clinical results of heparin surface modified (HSM) hydrophilic acrylic intraocular lens (IOL) with those of hydrophobic acrylic IOL. METHODS: One hundred patients with cataract were randomized to receive one of acrylic foldable IOLs after phacoemulsification: HSM hydrophilic acrylic IOL (n=50) BioVue3 (BioVue, OII, Ontario, CA, USA) and hydrophobic acrylic IOL (n=50) Sensar (AR40e, AMO, Santa Ana, CA, USA). Bestcorrected visual acuity and refractive error were measured at 1 week, 2 months, 6 months and 12 months after surgery in both IOL groups. To assess posterior capsular opacification (PCO), digital retroillumination image of posterior capsule was analyzed at 12 months using POCOman software. RESULTS: Best-corrected visual acuity (log MAR) was 0.032+/-0.082 in BioVue3 group and 0.034+/-0.077 in Sensar group at 12 months. There was no statistically significant difference between the two groups (p=0.554). Refractive error was -0.247+/-0.821 diopter in BioVue3 group and -0.264+/-0.808 diopter in Sensar group at 12 months. There was no statistically significant difference of refractive error between the two groups (p=0.909). At 12 months, BioVue3 IOL group had a lower percentage area and severity of PCO than Sensar group. However, it was not statistically significant (p=0.349, p=0.288). No Nd:YAG capsulotomy was performed in BioVue3 group while it was required in two eyes (4.0%) in Sensar group. CONCLUSIONS: There was no statistically significant difference of postoperative visual acuity, refractive error and degree of PCO between HSM hydrophilic acrylic IOL and hydrophobic acrylic IOL.

Incidence and risk factors for ocular GVHD after allogeneic hematopoietic stem cell transplantation.

We analyzed the incidence and risk factors for ocular GVHD in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Korea. In this retrospective, noncomparative, observational study, 635 subjects were included who had at least 2 years of follow-up ophthalmological examinations after allo-HSCT from 2009 to 2012 at Seoul St Mary's Hospital, Seoul, Korea. The mean duration between allo-HSCT and onset of ocular GVHD was 225.5±194.3 days. The adjusted incidence for acute ocular GVHD was 1.33% and that for chronic GVHD was 33.33%. In the multivariate analysis, preexisting diabetes mellitus (odds ratio (OR): 4.22, 95% confidence interval (CI): 1.66-10.72), repeated allo-HSCT (OR: 29.10, 95% CI: 1.02-8.28) and the number of organs that chronically developed GVHD by stage I (OR: 14.63, 95% CI: 9.81-21.84) increased risk of ocular GVHD. Careful monitoring of ocular GVHD is needed in patients with chronic GVHD in multiple organs and preexisting diabetes.

Prostaglandin E in rabbit aqueous humor after Nd-YAG laser photodisruption of iris and the effect of topical indomethacin pretreatment.

Ocular changes (prostaglandin E, protein, pupil diameter, and intraocular pressure) induced by photodisruption of pigmented rabbit iris with neodymium-yttrium aluminum garnet (Nd-YAG) laser and the effect of topical indomethacin upon those changes were examined. Concentrations of prostaglandin E in laser-treated eyes (1,3,5,10, and 20 lesions) were substantially greater than those in normal eyes and were associated with an initial hypertensive response. This finding was particularly striking in the case of 20 lesions. In that case, concentrations of prostaglandin E increased 50-fold, from 99 pg/ml of control level to 5049 pg/ml 60 min after irradiation. Disruption of blood aqueous barrier measured by protein concentration, changes in intraocular pressure, and pupil diameter occurred at a similar dose range of laser application. Concentration of protein and changes in pupil diameter already were prominent at 15 min after laser treatment, and changes in intraocular pressure were prominent at 60 min. Indomethacin pretreatment abolished most of these responses, suggesting that acute reactions following photodisruption largely depended on prostaglandin synthesis in iris tissue.

Role of transforming growth factor-beta in transdifferentiation and fibrosis of lens epithelial cells.

PURPOSE: To determine the levels of mRNAs encoding markers of fibrosis in lens epithelial cells (LECs) from patients with anterior polar cataracts and to test whether transforming growth factor (TGF)-beta enhances the expression of mRNAs for mesenchymal markers in LECs. METHODS: LECs attached to the anterior capsules of patients with nuclear or anterior polar cataracts were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) for the expression of mRNAs encoding pathologic extracellular matrix proteins, a marker of myofibroblast transformation, growth factors, and growth factor receptors, and by western blot analysis for the proteins encoded by these mRNAs. Bovine lens epithelial explants and intact rabbit lenses cultured with or without TGF-beta1 were also subjected to RT-PCR and western blot analysis. RESULTS: The levels of fibronectin, type I collagen, and alpha-smooth muscle actin (SMA) mRNAs were higher in LECs from patients with anterior polar cataracts than in those from patients with nuclear cataracts. Expression of mRNAs for TGF-beta1, TGF-beta2, TGF-beta receptor type II, and connective tissue growth factor (CTGF) was significantly greater in anterior polar type than in nuclear type cataracts. In contrast, expression of mRNAs for epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), fibroblast growth factor (FGF)-2, and FGF receptor-1 was similar in LECs from the two types of cataracts. TGF-beta1 markedly increased the levels of fibronectin, type I collagen, and alpha-SMA mRNA in bovine lens epithelial explants and intact rabbit lenses. CONCLUSIONS: This is the first finding showing altered mRNA expression in LECs from anterior polar cataracts. Enhanced expression of TGF-beta and the TGF-beta receptor suggests that TGF-beta derived from LECs may function in an autocrine fashion as the prime mediator of transdifferentiation and pathogenesis in human LECs. Elevated levels of CTGF mRNA suggest that this growth factor may play a role in the increased deposition of extracellular matrix in metaplastic LECs.

T-cell mediated responses in a murine model of orthotopic corneal transplantation.

PURPOSE: To evaluate the role that delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte responses play in a murine model of orthotopic corneal allograft transplantation. METHODS: Corneal transplantation was performed by grafting C57BL/6 donor corneas into BALB/c corneal beds. After transplantation, the mice were observed by slit lamp biomicroscopy on a weekly basis and graded for signs of graft rejection and delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses to donor alloantigens assessed at selected times after grafting. RESULTS: It was determined that between 40% and 65% of BALB/c mice rejected C57BL/6 corneas by 8 weeks after engraftment. Mice with opacity scores > 2 demonstrated significantly greater DTH responses than did mice with opacity scores < 2 at 2, 3, and 4 weeks after engraftment. After 4 weeks, the DTH responses for all groups were essentially the same as for naive BALB/c mice. The DTH responses were specific for C57BL/6 alloantigens and are primarily directed against non-major histocompatibility complex (MHC) C57BL/6 alloantigens and are primarily directed against non-major histocompatibility complex C57BL/6 alloantigens, as evidenced by the ability of B10.D2 cells to elicit DTH responses whereas C.B10-H-2b cells did not. However, although BALB/c mice engrafted with C57BL/6 tail skin demonstrated significantly greater CTL activity than naive BALB/c mice, there was no significant difference in CTL activity between BALB/c mice whose C57BL/6 corneal allografts displayed opacity scores greater than (rejected) or less than (accepted) 2. CONCLUSIONS: The mechanism whereby corneal allografts in this strain combination are rejected is best associated with the ability to generate strong DTH responses and not CTL activity. This DTH response also demonstrates alloantigen specificity and appears to be primarily directed against the non-MHC component of the corneal transplant.

In vitro propagation of primary and extended life span murine corneal endothelial cells.

PURPOSE: To establish primary and extended life span cell cultures of murine corneal endothelial cells for a model system investigating corneal endothelial cell replacement and the immunologic features of corneal graft rejection. METHODS: The authors have been able to grow corneal endothelium in culture by isolating adult murine Descemet's membrane and allowing the endothelial cells to proliferate from the explants. To isolate extended life span murine corneal endothelial cells, cells were infected with an adenovirus-SV40 hybrid virus (Ad12-SV40). RESULTS: The primary cells from adult corneas proliferated to passage 3 before growth arrest-senescence was observed. However, the extended life span cells remained proliferative through passage 36 and maintained a structure similar to the primary cells. Immunohistochemical analysis demonstrate that the extended life span cells are SV40 large T antigen positive, and both the primary and extended life span murine corneal endothelial cells exhibit the common expression of several growth factor receptors and TGF-beta. CONCLUSIONS: This is the first report of the isolation and culture of mouse corneal endothelial cells. Additionally, these cells have been infected with a virus carrying the SV40 large T antigen, which yields extended life span mouse corneal endothelial cells. These cells will be of interest in establishing a murine model for corneal cell transplantation, and the authors are currently establishing protocols for the specific introduction and manipulation of these cells in both in vitro and in vivo systems. These types of analyses may provide an important animal model specific to in vivo corneal endothelial cell replacement for the treatment of endothelial-related keratopathies and can be a useful model in delineating the immunologic parameters of corneal graft rejection.

Reactive oxygen species-induced apoptosis and necrosis in bovine corneal endothelial cells.

PURPOSE: The loss of corneal endothelial cells associated with aging and possibly other causes has been speculated to be related to exposure to reactive oxygen species (ROS). The current study was conducted to investigate, by use of photosensitizers, the underlying mechanisms involved in the death of bovine corneal endothelial cells (BCENs) caused by ROS. METHODS: BCEN cells in primary culture were treated with a photosensitizer (riboflavin or rose bengal) with light exposure. The patterns of cell damage and death were assessed using an acridine orange-ethidium bromide differential staining method, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and transmission electron microscopy. The cytotoxicity was assayed by mitochondrial function using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. Antioxidants, including catalase, L-histidine, salicylic acid, and superoxide dismutase, were used to determine the types of ROS involved. Activation of nuclear factor (NF)-kappaB was examined by fluorescent immunocytochemistry with anti-p65 antibody. RESULTS: Light-irradiated riboflavin or rose bengal resulted in a significant decrease in viability of BCEN cells. Chromosomal condensation and fragmentation were observed in apoptotic cells, and membrane lysis and damage of cell ultrastructures were observed in necrotic cells. Riboflavin induced apoptosis at 30 minutes and thereafter and induced necrosis after 2 hours. Rose bengal was shown to cause similar effects within half the time required for the effects of riboflavin. Catalase and salicylic acid were found to provide protection for BCENs from cytotoxic effects of riboflavin, and L-histidine was found to protect BCENs from cytotoxicity induced by rose bengal. Kinetic studies using immunocytochemistry showed that NF-kappaB was translocated into the nucleus within 15 minutes and 30 minutes after treatment with rose bengal and riboflavin, respectively. CONCLUSIONS: The cytotoxic effects of photo-irradiated riboflavin and rose bengal are shown to be mediated by two distinct but parallel pathways, one leading to apoptosis and the other to necrosis. Possible involvement of NF-kappaB in cell death is suggested. These findings provide potential leads for future investigation into the molecular mechanisms of loss of corneal endothelial cells related to aging, oxidative stress, and possibly other similar causes.

Overexpression of the transforming growth factor-beta-inducible gene betaig-h3 in anterior polar cataracts.

PURPOSE: In anterior polar cataracts and the fibrosis that can occur after cataract surgery, lens epithelial cells synthesize abundant extracellular matrix molecules and transdifferentiate into myofibroblast-like cells. Transforming growth factor (TGF)-beta has been implicated as a key player in these cataractous changes. The purpose of this study was to determine whether the TGF-beta-inducible gene h3 (betaig-h3) is expressed in lens epithelial cells from patients with anterior polar cataracts and to test whether betaig-h3 is induced by TGF-beta in cultured lens epithelial cells. METHODS: Lens epithelial cells attached to the anterior capsules of human cataractous lenses and noncataractous lenses were examined for the expression of betaig-h3 mRNA and protein using reverse transcription-polymerase chain reaction and immunohistochemical analyses. The effect of TGF-beta on betaig-h3 gene expression was also tested in human lens epithelial B-3 cells using Northern and Western blot analyses. RESULTS: betaig-h3 mRNA was not detected in lens epithelial cells from patients with clear lenses or patients with nuclear cataracts. Significant expression of mRNA for betaig-h3 was observed in lens epithelial cells from patients with anterior polar cataracts. Immunohistochemical analysis using anti-betaig-h3 antiserum indicated that betaig-h3 protein was present within the subcapsular plaques of anterior polar cataracts. Treatment of human lens epithelial B-3 cells with TGF-beta1 led to an increase in betaig-h3 mRNA and the secretion of betaig-h3 protein into the culture medium. CONCLUSIONS: betaig-h3 may serve as a marker for anterior polar cataracts in addition to previously known proteins, fibronectin, type I collagen, and alpha-smooth muscle actin. The functions of this protein in lens pathology need to be further investigated.

Necrosis and apoptosis after retinal ischemia: involvement of NMDA-mediated excitotoxicity and p53.

PURPOSE: Accumulated evidence has shown that apoptosis and necrosis contribute to neuronal death after ischemia. The present study was performed to study the temporal and spatial patterns of neuronal necrosis and apoptosis after ischemia in retina and to outline mechanisms underlying necrosis and apoptosis. METHODS: Retinal ischemia was induced by increasing intraocular pressure to a range of 160 mm Hg to 180 mm Hg for 90 minutes in adult rats. The patterns of neuronal cell death were determined using light and electron microscopy and were visualized by TdT-dUTP nick-end labeling (TUNEL). The mRNA expression profile of p53 was examined using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization histochemistry. Immunohistochemistry was performed using anti-p53, anti-microtubule associated protein-2, and anti-glial fibrillary acidic protein antibodies. RESULTS: Within 4 hours after ischemia, neurons in the inner nuclear cell layer (INL) and ganglion cell layer (GCL) underwent marked necrosis, made apparent by swelling of the cell body and mitochondria, early fenestration of the plasma membrane, and irregularly scattered condensation of nuclear chromatin. After 3 days, the INL and GCL neurons showed further degeneration through apoptosis marked by cell body shrinkage, aggregation, and condensation of nuclear chromatin. Apoptotic neurons were also observed sparsely in the outer nuclear cell layer. Intravitreal injections of MK-801 prevented early neuronal degeneration after ischemia. Of note, mRNA and protein levels of p53, the tumor suppressor gene known to induce apoptosis, were increased in the retinal areas undergoing apoptosis 1 to 3 days after ischemic injury. CONCLUSIONS: Ischemia produces the N-methyl-D-aspartate-mediated necrosis and slowly evolving apoptosis of neurons in the retina. The latter may depend on the expression of the p53 proapoptosis gene.

Failure to activate NF-kappaB promotes apoptosis of retinal ganglion cells following optic nerve transection.

NF-kappaB is a transcription factor, which is activated by various stimuli. One of the well-known activators of NF-kappaB is oxidative stress, which is a cause of cell death in some tissue, or cell types. Optic nerve transection, axotomy, results in retinal cell death, because of oxidative stress, deprivation of neurotrophic factors, etc. Since it has been hypothesized that the retinal ganglion cell death after axotomy is due to the generation of reactive oxygen species, we investigated whether NF-kappaB is involved in the retinal cell death after axotomy. This study was performed to investigate the role of NF-kappaB in retinal ganglion cell death after optic nerve transection. We used double staining experiment by using anti-NF-kappaB antibody and ethidium bromide to observe the correlation of NF-kappaB activation and the cell death. NF-kappaB was observed only in the surviving cells. NF-kappaB translocation was observed 3 days after the optic nerve transection. The NF-kappaB inhibitor, sulfasalazine, was used to block the activation of NF-kappaB in the axotomized retina, and the number of ganglion cells was quantified using retrograde in the presence or absence of sulfasalazine after axotomy. Inhibition of NF-kappaB by sulfasalazine accelerated the degeneration of ganglion cells in the retina. The results suggest that the activated NF-kappaB plays a protective role from the cell death in the injured ganglion cells.

Immunocytochemical localization of nitric oxide synthase in the mammalian retina.

The localization of nitric oxide synthase (NOS) was investigated by immunocytochemistry and immunoblotting using an antiserum against neuronal NOS in the rat, mouse, guinea pig, rabbit and cat retinae. Western blot analysis of retinal tissue extracts showed that the NOS-immunoreactive band of 155 kDa was present in all species. In the rat, mouse, guinea pig and rabbit retinae, two types of amacrine cells and a class of displaced amacrine cells were consistently NOS-labeled. In the cat retina, unlike other mammals, one type of amacrine cells and two types of displaced amacrine cells showed NOS immunoreactivity. NOS immunoreactivity was further found in some bipolar cells of the rat and guinea pig, some interplexiform cells of the mouse, some photoreceptor cells of the rabbit and some Müller cells of the cat.

Horizontal cells of the rat retina are resistant to degenerative processes induced by ischemia-reperfusion.

The fate of calbindin D28k (calbindin)-labeled horizontal cells in the ischemic rat retina induced by increasing intraocular pressure was investigated by immunocytochemistry using an antiserum against calbindin. In the normal retina, strong calbindin-like immunoreactivity was seen in the horizontal cells, and the density of the labelled horizontal cells was 815.3+/-15.2 per mm2. The thickness of the treated retina became progressively thinner with increasing reperfusion time after the ischemic insult due to a loss of retinal cells in the inner and outer nuclear layers. However, the densities of the horizontal cells per mm2 were 814.0+/-26.4 at 1 week, 813.3+/-20.8 at 2 weeks, and 812.6+/-11.5 at 4 weeks, indicating that horizontal cells did not degenerate during experimental periods. Thus, calbindin may have a protective role for horizontal cells to ischemic insult by its ability to buffer calcium influx in the rat retina.

Effect of neodymium:YAG laser photodisruption on intraocular lenses in vitro.

Poly(methyl methacrylate) (PMMA) based intraocular lenses (IOLs) such as injection-molded PMMA and lathe-cut PMMA IOLs and soft IOLs such as silicone and poly(hydroxyethyl methacrylate)(polyHEMA) IOLs were tested for vulnerability to Nd:YAG laser photodisruption. The laser beam was focused on the posterior surface and inside of the IOLs in balanced salt solution. Cracks and central defects with radiating fractures were observed in PMMA IOLs; blistered lesions and localized pits were observed in silicone and polyHEMA IOLs, respectively. A molten edge surrounding the large hole, which was an indication of the thermal effect of the laser, was observed in the injection-molded PMMA while only a minute lesion was found in the polyHEMA IOL which contained 38% water. The size of the superficial damage of the IOL increased as the power of laser irradiation increased and PMMA IOLs showed greater damage than soft IOLs (P < .05).

Compatibility of intraocular lenses with blood and connective tissue cells measured by cellular deposition and inflammatory response in vitro.

Injection molded poly(methyl methacrylate) (IM-PMMA), lathe-cut PMMA (LC-PMMA), heparin surface modified PMMA (HSM-PMMA), silicone, and polyhydroxyethyl methacrylate (polyHEMA) intraocular lenses (IOLs) were incubated with platelets, granulocytes, mouse macrophage-like RAW 264.7 cells and mouse fibrosarcoma L929 cells to examine their compatibility. The number of cells attached to the IOL was counted after the central IOL area (0.04 mm2) was photographed with an inverted light microscope. Cell morphology was examined by scanning electron microscopy (SEM). More platelets and granulocytes were attached to the IM-PMMA and silicone IOLs than to the HSM-PMMA and polyHEMA IOLs (P less than .05). RAW 264.7 and L929 cells grew on PMMA-based and silicone IOLs, whereas HSM-PMMA and polyHEMA IOLs did not support an abundant growth of these cells. Granulocytes were incubated with the IOLs in the presence of Luminol and the generation of chemiluminescence was measured. Poly(methyl methacrylate)-based IOLs caused granulocytes to release significant amounts of oxygen radicals, while the polyHEMA IOL was almost inactive in stimulating granulocytes. Silicone and HSM-PMMA IOLs showed an intermediate level of stimulating activity. The light intensity reached a peak within 14 minutes with the IM-PMMA IOL, and in about 18 minutes with the other IOLs. Our results suggest that IOL hydrophilicity prevents attachment of cells and that a hydrophilic, soft surface can discourage granulocyte stimulation.

Corneal ectasia detected after laser in situ keratomileusis for correction of less than -12 diopters of myopia.

We report 2 cases of corneal ectasia detected after laser in situ keratomileusis (LASIK) for the correction of less than -12.0 diopters (D) of myopia. Patients were evaluated before and after LASIK by corneal topography and pachymetry. After treatment, visual acuity temporarily improved but was followed by visual impairment, with corneal ectasia detected by topography. There may be a risk of corneal ectasia after LASIK in cases of myopia of less than -12.0 D. Despite thelow incidence, we recommend that LASIK be restricted to cases in which more than half the original corneal thickness and more than 250 microns of the stromal bed can be preserved. Careful examination, including preoperative serial topographic evaluation and measurement of posterior stromal thickness, should be performed to improve the quality and predictability of corneal refractive surgery.

Phacoemulsification with a bevel-down phaco tip: phaco-drill.

We present a technique for in situ lens nucleus emulsification using low phaco power and high vacuum, a continuous curvilinear capsulorhexis, and hydrodelineation. Emulsification is done with the phaco tip slanted down 30 or 45 degrees. Cutting and aspiration do not cause an undesirable energy loss. This technique can be combined with the nuclear chopping or divide and conquer methods because of its ability to drill and hold the nucleus. Posterior capsular rupture is prevented because the separated epinucleus acts as a barrier between the nucleus and the cortex. The low power used minimizes the energy transfer to the corneal endothelium. This technique is particularly useful in eyes with brunescent cataract.

Corneal flap thickness in laser in situ keratomileusis using an SCMD manual microkeratome.

PURPOSE: To evaluate corneal flap thickness in laser in situ keratomileusis (LASIK) and to measure variables correlated with corneal flap thickness. SETTING: Kangnam St. Mary's Hospital, Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Seoul, Korea. METHODS: This prospective study comprised 69 eyes of 66 patients having LASIK with the VISX Star laser and SCMD manual microkeratome. Corneal thickness, keratometry, and refractive error were measured preoperatively, the time taken to complete the corneal flap and its thickness were recorded intraoperatively, and visual outcome was followed postoperatively. Corneal flap thickness was calculated as the thickness of the corneal stromal bed subtracted from the total corneal thickness. RESULTS: Mean corneal flap thickness was 137.18 microns +/- 33.66 (SD). The thickness in 32 eyes (46.4%) was less than 135 microns, in 17 eyes (24.6%) from 135 to 165 microns, and in 20 eyes (29.0%) greater than 165 microns. There was no relationship between corneal flap thickness and degree of myopia, steepening of cornea, or time taken to complete the flap. However, the thickness of the corneal flap increased with the thickness of the cornea. Visual outcome was slightly better in the group with thick corneal flaps than in the one with thin corneal flaps, although the difference was not statistically significant. CONCLUSION: Corneal flap thickness was variable in LASIK using the SCMD microkeratome. There was a correlation between corneal flap thickness and preoperative corneal thickness.