Kyoo Won Lee

Conjunctivolimbal Autograft Using a Fibrin Adhesive in Pterygium Surgery

Purpose To evaluate the efficacy and safety of fibrin bioadhesive in conjunctivolimbal autograft surgery for primary pterygium. Methods Thirty-six eyes in 34 patients were reviewed with nasal primary pterygium who were treated with pterygium excision with superior conjunctivolimbal transplantation with fibrin bioadhesive. Surgical durations were recorded and the patients were followed up on the first day after surgery and then at 1, 2, 4, 8 and 12 weeks postoperatively. The graft-recipient site attachments were examined and subjective symptoms of patients were recorded at every follow-up examinations. Results The mean patient age was 57.9±10.1 (ranging from 33 to 83) years. The mean follow-up period was 22.05±5.78 weeks. The mean surgery time was 18.04±5.65 minutes. The subjective symptoms (pain, foreign body sensation, tearing and discomfort) disappeared in 23 of 36 eyes (64%) in one week after surgery, and all discomforts subsided within two weeks after surgery in all patients. The conjunctivolimbal autograft was correctly positioned and fixed in 34 of 36 eyes (94.4%) throughout the follow-up period. Graft dehiscence was seen in two eyes (5.6%), one eye was treated with remedial sutures, and the other eye showed a spontaneous healing without remedial sutures. Transient graft edema occurred in four eyes (11.2%) but subsided spontaneously within a month. There were no cases of pterygium regrowth or complications due to the fibrin bioadhesive. Conclusions The use of fibrin bioadhesive in conjunctivolimbal autograft surgery in primary pterygium simplifies surgical techniques, shorten surgical duration, and produce less postoperative subjective symptoms. Therefore, the fibrin bioadhesive is a safe and effective tool to attach conjunctivolimbal autograft in primary pterygium surgery.

In Vitro Effects of Preservative-free and Preserved Prostaglandin Analogs on Primary Cultured Human Conjunctival Fibroblast Cells

Purpose Long-term use of topical medication is needed for glaucoma treatment. One of the most commonly prescribed classes of hypotensive agents are prostaglandin analogs (PGs) used as both first-line monotherapy; as well as in combination therapy with other hypotensive agents. Several side effects of eye drops can be caused by preservatives. The purpose of this study was to evaluate the effects of PGs with varying concentrations of benzalkonium chloride (BAC), alternative preservatives, or no preservatives on human conjunctival fibroblast cells. Methods Primary human conjunctival fibroblast cells were used in these experiments. Cells were exposed to the following drugs: BAC at different concentrations, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), tafluprost 0.0015% with/without 0.001% BAC and travoprost 0.004% (with 0.001% Polyquad) for 15 and 30 minutes. Cell cytotoxicity was evaluated by phase-contrast microscopy to monitor morphological changes of cells, Counting Kit-8 (CCK-8) assay to cell viability, and fluorescent activated cell sorting (FACS) analysis to measure apoptosis. Results BAC caused cell shrinkage and detachment from the plate in a dose-dependent manner. Morphological changes were observed in cells treated with bimatoprost 0.01% and latanoprost 0.005%. However, mild cell shrinkage was noted in cells treated with tafluprost 0.0015%, while a non-toxic effect was noted with travoprost 0.004% and preservative-free tafluprost 0.0015%. CCK-8 assay and FACS analysis showed all groups had a significantly decreased cell viability and higher apoptosis rate compared with the control group. However, travoprost 0.004% and preservative-free tafluprost 0.0015% showed lower cytotoxicity and apoptosis rate than other drugs. Conclusions This in vitro study revealed that BAC-induced cytotoxicity is dose-dependent, although it is important to emphasize that the clinical significance of toxicity differences observed among the different PGs formulations has not yet been firmly established. Alternatively preserved or preservative-free glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

In Vivo Effects of Preservative-free and Preserved Prostaglandin Analogs: Mouse Ocular Surface Study

Purpose Chronic use of topical hypotensive agents induces several side effects caused by preservatives. The purpose of this study was to evaluate the effects of prostaglandin analogs with varying concentrations of benzalkonium chloride (BAC), preservative-free (PF), and alternative preservatives on mouse corneal tissue. Methods Thirty-five, 8- to 10-week-old female C57BL/6 mice (five mice for each group) were used for this study. To the control group, we applied normal saline, and to each drug-treated group we applied 0.02% BAC, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), travoprost 0.004% (with 0.001% polyquad) or tafluprost 0.0015% with/without 0.001% BAC, once a day (9 p.m.) for 4 weeks. Corneal fluorescein staining was evaluated in all groups. After harvest, the corneal tissues were embedded in paraffin and then Hematoxylin-Eosin stain was performed for histopathological examination. Immunofluorescence staining was done against TNF-α, IL-6, HLA DR, pJNK, and pAkt. Results In corneal fluorescein staining, severe punctate epithelial keratitis was seen in the groups of 0.02% BAC, 0.02% BAC containing bimatoprost 0.01% and latanoprost 0.005%. The surface desquamation, irregular surface, loss of cell borders, anisocytosis and stromal shrinkage were observed in the groups of BAC-containing eye drops. Moreover, the groups treated with BAC-containing eye drops have high inflammatory markers, significantly decreased cell viability-related signal, pAkt, and higher apoptosis-inducing signal, pJNK, than the control group. On the other hand, travoprost 0.004% and PF tafluprost 0.0015% have less cellular morphologic changes, lower inflammation, and higher cellular viability than BAC-containing formulations. Conclusions Corneal damage, increased inflammation and apoptosis and low cell viability were observed in BAC-containing groups. PF or alternatively preserved glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

Prognostic Factors for the Success of Laser Iridotomy for Acute Primary Angle Closure Glaucoma

Purpose To identify the prognostic factors for successful laser iridotomy for acute angle-closure glaucoma (AACG). Methods We retrospectively reviewed the medical records of 77 eyes of 77 patients with AACG with initial intraocular pressure (IOP) above 40 mmHg. All of the patients received maximum tolerable medical therapy (MTMT) followed by laser iridotomy. In order to comparatively analyze the factors affecting successful laser iridotomy, an increase in IOP on follow-up was defined as increase in IOP greater than 21 mmHg requiring medical or surgical treatment. Results Successful laser iridotomy was achieved in 59.7% (46/77 eyes). Thirty-one eyes (40.3%) exhibited increased IOP on follow-up, and of these, 30 eyes developed an increase in IOP within six months after the first attack. The success rate was higher (92.9%) in 42 patients who had greater than 30% IOP reduction by MTMT at the first attack compared to the 35 patients whose IOP reduction was less than 30%, of which 24 eyes (72.7%) showed more than 30% IOP reduction after intravenous hyperosmotic agent treatment (p=0.012). The success rate was higher in patients treated within seven days after the development of symptoms than in those treated after seven days (Odds ratio, 4.51; 95% confidence interval, 1.38 to 14.75). Conclusions Our data suggest that we can expect successful IOP control after laser iridotomy in eyes with AACG if the patient can be treated within seven days after the development of symptoms and if the IOP reduction was more than 30% by MTMT.

Comparison of the Efficacy of Fluorometholone With and Without Benzalkonium Chloride in Ocular Surface Disease.

Purpose: The purpose of this study was to compare the cytotoxicity and antiinflammatory effect of preserved and unpreserved 0.1% fluorometholone (FML). Methods: Drug-induced morphological changes and cytotoxicity were examined in human corneal epithelial cells. Dry eye was induced in mice by treatment with 0.2% benzalkonium chloride (BAC) for the first 2 weeks, and then, the eyes (4 groups; Normal saline, BAC, preserved FML, and unpreserved FML) were treated thrice daily with each formulation for the next 2 weeks. Corneal tissues were embedded in paraffin and stained with hematoxylin and eosin for histopathological examination. Immunofluorescence staining was performed for tumor necrosis factor-&agr;, interleukin-6, and human leukocyte antigen–DR. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed to evaluate drug-induced cytotoxicity. Results: BAC and preserved FML caused cell shrinkage and detachment from the plate in a dose-dependent manner, and cell viability decreased significantly. However, cytotoxicity was reduced on treatment with unpreserved FML. Hematoxylin-eosin staining revealed surface desquamation, irregular surface, loss of cell borders, and stromal shrinkage in the group treated with BAC. On BAC exposure, tumor necrosis factor-&agr;, interleukin-6, and human leukocyte antigen–DR were strongly detected, and cytotoxicity was markedly increased, as evidenced by a positive result in the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Ocular surface damage and inflammation were slightly reduced on treatment with preserved FML. In comparison, unpreserved FML did not induce morphological changes; moreover, decreased cell cytotoxicity and ocular surface inflammation were observed. Conclusions: The cytotoxicity of antiinflammatory eye drops evaluated in this study was induced by the preservative BAC. Accordingly, unpreserved FML is more effective than preserved eye drops in decreasing ocular inflammation.

Comparison of the Thickness of the Lamina Cribrosa and Vascular Factors in Early Normal-tension Glaucoma with Low and High Intraocular Pressures

Purpose To compare the thickness of the lamina cribrosa (LC) and vascular factors of early normal-tension glaucoma (NTG) patients with high and low intraocular pressure (IOP) that are expected to be associated with the development of glaucoma. Methods Seventy-one Korean NTG patients with low IOP (the highest IOP <15 mmHg, 40 patients) and high IOP (the lowest IOP >15 mmHg, 31 patients) were included in this study. The thickness of LC and vascular factors were compared. The thickness of the LC was measured using the enhanced depth imaging method with spectral domain optical coherence tomography (Heidelberg Spectralis). Results The mean thickness of the central LC was 190.0 ± 19.2 µm in the low IOP group and 197.8 ± 23.6 µm in the high IOP group, but there was no statistical significant difference between the two groups (p > 0.05). The prevalence of self-reported Raynaud phenomenon was significantly higher in the low IOP group (33.0%) than the high IOP group (10.3%, p = 0.04). Conclusions The laminar thickness did not significantly differ between the high and low IOP groups. However, the prevalence of Raynaud phenomenon was higher in the low IOP groups. These results suggest that the development of glaucoma with low IOP patients may be more influenced by peripheral vasospasm, such as Raynaud phenomenon, rather than laminar thickness in NTG.

Cyclosporine A Downregulates MMP-3 and MMP-13 Expression in Cultured Pterygium Fibroblasts.

Purpose: To investigate the regulation of matrix metalloproteinase (MMP)-3 and MMP-13 expression over time and in the presence of cyclosporine A (CsA) in primary cultured human pterygium fibroblasts. We also examined the effects of CsA on cultured human pterygium fibroblasts. Methods: Primary cultured human pterygium fibroblasts subjected to scratch assays were exposed to 1 and 100 µg/mL of CsA for 3 or 10 minutes. Cells were washed with Dulbecco phosphate-buffered saline, and then incubated with serum-depleted Dulbecco modified Eagle medium/F-12 medium for 48 hours. Expression levels of MMP-3 and MMP-13 proteins and the corresponding mRNA transcripts were determined by western blotting and reverse transcription polymerase chain reaction assays, respectively. Results: Migration of cultured pterygium fibroblast cells was suppressed by pretreatment with CsA compared with controls in a time-dependent and dose-dependent manner (3 minutes, 50.6% ± 1.1 in 1 µg/mL, 60.0% ± 1.2 in 100 µg/mL; 10 minutes, 59.8% ± 5.7 in 1 µg/mL, 60.5 ± 2.4 in 100 µg/mL, respectively, P < 0.01). Pretreatment with CsA also reduced the mRNA (P < 0.05) and protein expression levels (P < 0.05). Conclusions: CsA was actively involved in the migration of pterygium fibroblasts. Cell migration is inhibited in response to CsA through the inhibition of MMP-3 and MMP-13 expression. These findings reveal the therapeutic potential of CsA on pterygium progression. Further studies will be necessary to elucidate the precise intracellular signal mechanism responsible for CsA-induced downregulation of MMPs in pterygium fibroblasts.

Choroidal Thickness Variation According to Refractive Error Measured by Spectral Domain-optical Coherence Tomography in Korean Children

Purpose To assess choroidal thickness (CT) variation according to refractive errors using enhanced-depth imaging optical coherence tomography. Methods Eighty-nine eyes (in 89 children) <±6 diopter were categorized into three groups: hyperopia, emmetropia, and myopia, according to refractive error, and underwent choroidal scans using enhanced-depth imaging-optical coherence tomography. CT was measured at the fovea and at 1 mm and 3 mm nasal (N1 and N3), temporal (T1 and T3), superior (S1 and S3), and inferior (I1 and I3) from the fovea. Results Mean foveal CTs were 346.86 µm, 301.97 µm, and 267.46 µm in the hyperopia, emmetropia, and myopia groups, respectively (p < 0.05). CTs at N3 and T3 were 214.59 µm and 318.68 µm, 163.92 µm and 320.79 µm, and 153.93 µm and 295.61 µm in the hyperopia, emmetropia, and myopia groups, respectively (p < 0.05). All CTs in the hyperopia group were thicker than those of other groups (p < 0.05). Fovea was thickest and was significantly thicker than at N3 and I3 in hyperopia (p < 0.05). T3 thickness in the emmetropia and myopia groups was greater than thickness at other areas, particularly the nasal and inferior choroids (p < 0.05). CT was positively correlated with spherical equivalent (p = 0.029). Conclusions In Korean children, CTs were greater in the hyperopia group than in the emmetropia and myopia groups. The temporal choroid was thicker than the nasal choroid, regardless of the refractive error. The thickest location in the hyperopia group was the fovea; however, the temporal choroid was thickest in the emmetropia and myopia groups.

Cyclosporine A inhibits TGF-β2-induced myofibroblasts of primary cultured human pterygium fibroblasts

Cyclosporine A (CsA), an immunomodulatory drug, and is increasingly used to treat moderate dry eye syndrome and ocular surface inflammation. However, any inhibitory effect on differentiation of fibroblasts to myofibroblasts remains unclear. Here, we show that the inhibitory effect of CsA on transforming growth factor-beta2 (TGF-β2)-induced myofibroblasts in primary cultured human pterygium fibroblasts. CsA significantly decreased mRNA and protein expression of myofibroblast-related markers including α-SMA, laminin, and fibronectin. These findings were supported by the results from immunofluorescence staining. Taken together, these results indicate the therapeutic potential of CsA against pterygium progression. Further studies are necessary to elucidate the precise intracellular signal mechanism responsible for CsA-induced downregulation of myofibroblast markers in pterygium fibroblasts.

Inhibition of Pterygium Fibroblast Migration and Outgrowth by Bevacizumab and Cyclosporine A Involves Down-Regulation of Matrix Metalloproteinases-3 and -13

We examined the connection between matrix metalloproteinase (MMP) expression/activity and pterygium fibroblast migration, and how these were affected by bevacizumab and/or cyclosporine A (CsA). Fibroblasts were obtained from 20 pterygia and 6 normal conjunctival specimens. Expression levels of MMP-3 and MMP-13 were examined after bevacizumab administration. Immunofluorescence staining was used to examine expression of both MMPs in fibroblasts migrating out from explanted pterygium tissues. Rates of cell migration from explant-cultured pterygia tissues and scratch-wounded confluent pterygium fibroblasts were examined in the presence of MMP-3 or MMP-13 inhibitors, as well as bevacizumab and/or CsA. A scratch wound healing migration assay was performed to determine the effects of bevacizumab and/or CsA. Protein expression of both MMPs in pterygium tissues and in cells migrating from organ-cultured pterygium tissues was greater than that observed in normal cells. Inhibition of the activities of both MMPs decreased their expression levels; these were also significantly reduced in bevacizumab-injected pterygium tissues. Bevacizumab significantly reduced the expression of both MMPs and cell migration. Pretreatment with CsA prior to bevacizumab exposure markedly inhibited cell migration and the expression of both MMPs. CsA enhanced the inhibitory effects of bevacizumab on pterygium fibroblast migration in vitro, possibly by inhibiting expression of both MMPs. These findings suggest that combined CsA and bevacizumab treatment may provide a potential therapeutic strategy for reducing the rate of pterygium recurrence.