THE ASSOCIATION BETWEEN CENTRAL SEROUS CHORIORETINOPATHY AND SLEEP APNEA: A Nationwide Population-Based Study.

PURPOSE: To identify the association between sleep apnea (SA) and central serous chorioretinopathy (CSC). METHODS: In this nationwide population-based study using the Taiwan National Health Insurance Database, we enrolled adult patients with a diagnosis of SA and matched each patient to 30 age- and gender-matched control subjects without any SA diagnosis. Using Poisson regression analyses, the incidence rate of CSC was compared between SA patients and control subjects. RESULTS: A total of 10,753 SA patients and 322,590 control subjects were identified. After adjusting for age, gender, residency, income level, and comorbidities, the incidence rate of CSC was significantly higher in SA patients than in the control subjects (adjusted incident rate ratio for probable SA: 1.2 [95% CI: 1.1-1.4], P < 0.0001). Analyses of the propensity score-matched subpopulations also confirmed our findings. Risk factors for CSC in SA patients included male gender, age ≤50 years, higher income, presence of heart disease, absence of chronic pulmonary disease, and presence of liver disease. In SA patients, those who had received continuous positive airway pressure titration had a significantly lower incidence rate of CSC than the others. CONCLUSION: Our study revealed a significantly higher incidence rate of CSC in SA patients compared with the control subjects.

MANAGEMENT OF REFRACTORY LARGE MACULAR HOLE WITH AUTOLOGOUS NEUROSENSORY RETINAL FREE FLAP TRANSPLANTATION.

PURPOSE: To investigate the morphological and functional outcome of refractory large macular hole (MH) with autologous neurosensory retinal free flap transplantation. METHODS: This case series enrolled 10 patients suffering from refractory large MH at Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. All eyes underwent pars plana vitrectomy, a neurosensory retinal free flap with a 1.5 to 2-MH diameter was harvested. We used an adhesive agent such as whole blood or Viscoat to assist the stabilization of the retinal free flap and then use tamponade silicone oil to tamponade the vitreous cavity. Silicone oil was removed 6 months postoperatively. Main outcome measures including closure of MH and change in best-corrected visual acuity change were recorded. RESULTS: The mean age was 64.9 ± 11.5 years. Before presentation, all cases had received at least two vitreoretinal procedures including vitrectomy, internal limiting membrane peeling, and fluid-gas exchange. At last visit, closure of the MH was achieved in 9 of 10 (90%) cases. The mean preoperative best-corrected visual acuity and that after 12 months of surgery improved from 1.65 ± 0.43 logarithm of minimum angle of resolution to 0.88 ± 0.49 logarithm of minimum angle of resolution (P < 0.001). CONCLUSION: For eyes with refractory or large MH, autologous neurosensory retinal free flap under silicone oil tamponade may provide a new option to improve the anatomical and function outcome, especially in cases where insufficient internal limiting membrane is left.

Ocular genetics in Taiwan.

PURPOSE OF REVIEW: Ocular genetics is an emerging specialty which has accompanied the advancement of modern genetic technology. This review is to understand the current status of practice in ocular genetics in Taiwan. RECENT FINDINGS: There is only one ocular genetics clinic in Taiwan. Certified clinical laboratories provide few gene tests in ocular genetics. Most ocular genetic study is focused on myopia. Financial obstacles are a major problem for patients to seek gene tests. SUMMARY: Despite a relatively successful, healthcare system in Taiwan, when compared with developed countries, ocular genetics is at an early stage of development. More financial resources and labor are needed to advance clinical care and research.

Hypoxia-induced vascular endothelial growth factor secretion by retinal pigment epithelial cells is inhibited by melatonin via decreased accumulation of hypoxia-inducible factors-1α protein.

BACKGROUND: Hypoxia is the most important stimulus leading to up-regulation of vascular endothelial growth factor (VEGF) in the retina via elevation of hypoxia-inducible factors-1α (HIF-1α) protein. The purpose of this study was to test the effects of melatonin on the expression of VEGF and HIF-1α in the cultured human retinal pigment epithelial (RPE) cells under normoxia and hypoxia. METHOD: An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2 ) to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without melatonin under normoxia and hypoxia. The protein and RNA levels of VEGF and HIF-1α were measured by ELISA kits and RT-PCR, respectively. RESULT: Hypoxia induced a significant increase of expression and secretion of VEGF and accumulation of HIF-1α protein in RPE cells (P < 0.05). Melatonin at 10-5 to 10-8 M significantly inhibited hypoxia-induced expression, the secretion of VEGF and the accumulation of HIF-1α protein (P < 0.05), but not affected expression of VEGF and HIF-1α under normoxia (P > 0.05). CONCLUSION: This study suggests that melatonin may have potential value in the prevention and treatment of various retinal diseases associated with increase of VEGF, vascular leakage and angiogenesis.

Tolerability and efficacy of bimatoprost 0.01 % in patients with open-angle glaucoma or ocular hypertension evaluated in the Taiwanese clinical setting: the Asia Pacific Patterns from Early Access of Lumigan 0.01 % (APPEAL Taiwan) study.

BACKGROUND: In randomized, controlled trials of open-angle glaucoma (OAG) or ocular hypertension (OHT), bimatoprost 0.01 % improved tolerability while retaining the intraocular pressure (IOP)-lowering efficacy of bimatoprost 0.03 %. Given geographic/racial differences in glaucoma presentation, the APPEAL study assessed the occurrence and severity of hyperemia produced by bimatoprost 0.01 %, and its efficacy, in the Taiwanese clinical setting. METHODS: In this multicenter, open-label, observational study, treatment-naïve and previously treated patients with OHT or OAG received once-daily bimatoprost 0.01 % for 12 weeks. Hyperemia (primary endpoint) was graded at baseline, week 6, and week 12 using a photonumeric scale (0, +0.5, +1, +2, +3), grouped (≤ +1, none to mild; ≥ +2, moderate to severe), and reported as unchanged from baseline, improved, or worsened. IOP assessments followed the same schedule. Supplemental efficacy analyses were conducted based on previous therapies. RESULTS: The intent-to-treat population (N = 312) included treatment-naïve (13.5 %) and previously treated (86.5 %) patients; mean age was 53.3 years. At baseline, 46.3 % of previously treated patients were receiving prostaglandin analog (PGA) monotherapy. At week 12, 91.2 %, 5.9 %, and 2.9 % of treatment-naïve patients exhibited unchanged, worsened, and improved hyperemia from baseline, respectively; 77.9 %, 12.9 %, and 9.2 % of previously treated patients showed no change, worsening, and improvement, respectively. There were no statistically significant shifts in hyperemia severity in either group, or in subgroups based on previous use of any PGA, any non-PGA, latanoprost, or travoprost monotherapies. In treatment-naïve patients, mean IOP reduction from baseline (18.0 ± 3.8 mm Hg) was 3.6 mm Hg at week 12 (P < 0.0001); 83.3 % had baseline IOP ≤ 21 mm Hg. In previously treated patients, mean additional IOP reduction from baseline (17.8 ± 3.9 mm Hg) was 2.6 mm Hg (P < 0.0001); similar results were observed in patient subgroups based on previous therapies. CONCLUSIONS: In the Taiwanese clinical setting, bimatoprost 0.01 % provided significant IOP lowering in treatment-naïve patients (regardless of baseline IOP) and previously treated patients (even those with relatively low IOP on other therapies), while causing no significant changes in hyperemia from baseline. TRIAL REGISTRATION: Clinicaltrials.gov NCT01814761 . Registered 18 March 2013.

Recognition of Glaucomatous Fundus Images Using Machine Learning Methods Based on Optic Nerve Head Topographic Features.

PRCIS: Machine learning classifiers are an effective approach to detecting glaucomatous fundus images based on optic disc topographic features making it a straightforward and effective approach. STUDY DESIGN: Retrospective case-control study. OBJECTIVE: The aim was to compare the effectiveness of clinical discriminant rules and machine learning classifiers in identifying glaucomatous fundus images based on optic disc topographic features. METHODS: The study used a total of 800 fundus images, half of which were glaucomatous cases and the other half non-glaucomatous cases obtained from an open database and clinical work. The images were randomly divided into training and testing sets with equal numbers of glaucomatous and non-glaucomatous images. An ophthalmologist framed the edge of the optic cup and disc, and the program calculated five features, including the vertical cup-to-disc ratio and the width of the optic rim in four quadrants in pixels, used to create machine learning classifiers. The discriminative ability of these classifiers was compared with clinical discriminant rules. RESULTS: The machine learning classifiers outperformed clinical discriminant rules, with the extreme gradient boosting method showing the best performance in identifying glaucomatous fundus images. Decision tree analysis revealed that the cup-to-disc ratio was the most important feature for identifying glaucoma fundus images. At the same time, the temporal width of the optic rim was the least important feature. CONCLUSIONS: Machine learning classifiers are an effective approach to detecting glaucomatous fundus images based on optic disc topographic features and integration with an automated program for framing and calculating the required parameters would make it a straightforward and effective approach.

Long-Term Follow-Up of Refractory Large Macular Hole with Autologous Neurosensory Retinal Free Flap Transplantation.

Purpose: To evaluate the long-term anatomic and functional outcomes of autologous neurosensory retinal free flap transplantation (ART) for patients with refractory large macular hole (MH). Design: Retrospective interventional case series. Methods: We reviewed 9 patients who underwent ART for their refractory large MH. In this extended follow-up study, postoperative assessment including spectral-domain optical coherence tomography and best-corrected visual acuity (BCVA) were recorded at 12, 15, 18, 21, and 24 months after surgery. Results: The macular hole of all patients appeared successfully closed during the whole follow-up period. The mean logMAR BCVA improved from 1.61 ± 0.44 (preoperative) to 0.72 ± 0.30 (12 months after surgery) (p < 0.001). Thereafter, the mean BCVA remained stable at each follow-up. At the mean 16.0 ± 0.8 months postoperatively, inner retinal cystic changes were observed in 4 eyes (44.4%), but these did not significantly affect vision. Conclusion: ART is a good alternative technique for closing large refractory macular holes. Although inner retinal cystic changes were observed in 4 eyes (44.4%), this phenomenon did not significantly affect visual acuity. It provides long-term good anatomical and functional results, especially in cases where insufficient ILM or lens capsule are left.

Heat shock induces apoptosis through reactive oxygen species involving mitochondrial and death receptor pathways in corneal cells.

Although many studies have been performed to elucidate the molecular consequences of ultraviolet irradiation, little is known about the effect of infrared radiation on ocular disease. In addition to photons, heat is generated as a consequence of infrared irradiation, and heat shock is widely considered to be an environmental stressor. Here, we are the first to investigate the biological effect of heat shock on Statens Seruminstitut Rabbit Cornea (SIRC) cells. Our results indicate that heat shock exhibits effective cell proliferation inhibition by inducing apoptosis. Heat shock triggers the mitochondrial apoptotic pathway indicated by a change in Bax/Bcl-2 ratios, resulting in caspase-9 activity. In addition, heat shock triggered the death receptor apoptotic pathway indicated by a change in Fas ligand expression, resulting in caspase-8 activity. Furthermore, we also found that generation of reactive oxygen species (ROS) is a critical mediator in heat shock-induced apoptosis. In addition, the antioxidant vitamin C significantly decreased heat shock-mediated apoptosis. Taken together, these findings suggest a critical role for ROS involving mitochondrial and death receptor pathways in heat shock-mediated apoptosis of cornea cells.

Pleiotropic role of atorvastatin in regulation of human retinal pigment epithelial cell behaviors in vitro.

Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, possess pleiotropic effects that have been extended to modulation of various cellular behaviors. This study aimed at examining whether atorvastatin (AVN) modulates cell growth, adhesion, migration, and contraction of cultured human retinal pigment epithelium (RPE) cells. The in vitro effects of AVN on human RPE cells was analyzed in terms of cell proliferation, cell cycle, cell adhesion, migration, and contraction assays. The modulatory effect of AVN on TGF-ß2-triggered signaling was determined by Western blotting detection. AVN at submicromolar dose exhibited no prominent morphological alteration and cytotoxicity, whereas it elicited cytostatic effect at concentrations higher than 1 µM. Cell cycle analysis showed that AVN induced growth arrest in both G1 and G2/M phases. AVN at 1 µM or higher concentrations significantly suppressed RPE cell adhesion. Cell migration and 3D collagen contraction assays showed that AVN significantly suppressed RPE cell migration and contractility, respectively. Mechanistically, AVN treatment transiently up-regulated phosphorylation of Akt, ERK1/2, and p38 MAPK, whereas down-regulated that of JNK1. Intriguingly, AVN pretreatment prominently attenuated the TGF-ß(2)-mediated non-Smad signaling, including Akt, ERK1/2, p38 MAPK, and JNK1 phosphorylation. Besides, it directly reduced constitutive level of myosin regulatory light chain peptide MYL9 and mitigated the TGF-ß(2)-induced phosphorylation of myosin phosphatase-targeting subunit 1, MYPT1. These in vitro findings strongly suggest that AVN possesses pleiotropic function on RPE cells, including anti-proliferation, anti-adhesion, anti-migration as well as anti-contraction. In conclusion, AVN treatment may be considered a useful therapy for proliferative vitreoretinal diseases.

A refractory malignant glaucoma posttrabeculectomy in vitrectomized eye: A case report and review of the literature.

The objective of this study is to report a case of refractory malignant glaucoma post trabeculectomy in vitrectomized eye and review of previous literature in PubMed database. A 63-year-old male encountered malignant glaucoma after trabeculectomy in vitrectomized eye. We had tried vitreous tapping with peripheral iridectomy and vitreous tapping with intracameral injection of room air (Chandler procedure). All of previous procedures were in vain. Finally, the yttrium-aluminum-garnet laser membranectomy with zonulectomy was done. The intraocular pressure is within normal range without any topical glaucoma eye drops during 3-year outpatient department regular follow-up. Complete vitrectomy with a patent tunnel from posterior chamber to anterior chamber (iridectomy-zonulectomy) is the effective procedure to manage of malignant-like glaucoma.

Mechanism of mitomycin-induced apoptosis in cultured corneal endothelial cells.

PURPOSE: Previous studies have indicated that improper use of mitomycin C (MMC) caused cytotoxicity in corneal endothelial cells. The aim of the present study was to investigate whether MMC induces cellular apoptosis in corneal endothelial cells and to determine the mechanism by which this may occur. METHODS: Porcine corneal endothelial cells were acquired from primary culture. Cellular damage and caspase pathway were estimated with a MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. The apoptotic characteristics were detected by means of flow cytometry, the TUNEL (terminal deoxyribonucleotidyl-transferase-(TdT)-mediated deoxyuridine-5'-triphosphate-digoxigenin (dUTP) nick-end labeling) test, immunofluorescent staining, and western blotting. RESULTS: The results indicated that MMC was toxic to corneal endothelial cells in a time-dependent and dose-dependent manner. Pretreatment with a general caspase inhibitor (Z-VAD-FMK), a caspase-8 inhibitor (Z-IETD-FMK), and a caspase-9 inhibitor (Z-LEHD-FMK) reversed MMC-induced cellular damage. Following exposure to MMC, a change in the mitochondrial membrane potential was positively detected by flow cytometric assay with MitoLight dye while cellular cytochrome c that was released from the mitochondria to the cytoplasm was detected by immunofluorescent staining. A positive TUNEL test revealed that cellular DNA apoptosis had occurred following exposure to 0.001 and 0.01 mg/ml MMC for 24 h. Positive annexin V-FITC, and negative propidium iodide (PI) staining indicated that the cellular plasma membrane underwent apoptosis following 0.001 mg/ml MMC exposure for 24 h. Western blot assay demonstrated down-regulation of the Bcl-2 protein and upregulation of the p53 and p21 proteins, which were all involved in apoptosis induced by MMC. CONCLUSIONS: These results indicate that mitomycin-induced cellular apoptosis in corneal endothelial cells may be mediated through caspase-8, caspase-9, and the mitochondrial regulated pathways as well as through upregulation of p53-dependent and p21-dependent signal transduction pathways.

Dexamethasone Intravitreal Implant (Ozurdex) for Long-Term Macular Edema after Epiretinal Membrane Peeling Surgery.

PURPOSE: To investigate the functional and anatomical outcome of the 0.7 mg dexamethasone (Ozurdex) intravitreal implant (IVD) in eyes with long-term macular edema after macular epiretinal membrane removal. METHODS: We enrolled 40 eyes with persistent macular edema at least 12 months after epiretinal membrane removal. Twenty eyes in the IVD group received IVD and the other 20 eyes were in the control group. The main outcome measures were change in best-corrected visual acuity (BCVA) and central foveal thickness (CFT). RESULTS: For eyes in the IVD group, the mean BCVA improved by 3.45 lines to 0.47 logMAR one month after IVD. However, the mean BCVA improved by only 0.14 lines to 0.74 logMAR at the same time in eyes in the control group. Six months later, the mean BCVA improved to 0.31 and 0.74 logMAR in the IVD and control groups, respectively. In the IVD group, the mean CFT decreased rapidly by 116.8 µm to 333.9 µm one month after IVD. Thereafter the CFT decreased at a slower pace. In the control group, the CFT remained static during the follow-up period. However, in the IVD group, 6 months after IVD, the CFT seemed to have a tendency to increase. CONCLUSIONS: Single IVD could significantly decrease macular edema and improve visual outcome for eyes with persistent long-term macular edema after macular ERM removal and the effect can be sustained as long as 6 months after the initial injection. However, in order to maintain the visual and anatomical outcome, repeat IVD might be considered if macular edema recurs.

Comparison of Visual Outcome and Morphologic Change between Different Surgical Techniques in Idiopathic Epiretinal Membrane Surgery.

PURPOSE: To investigate the morphological and functional outcomes of idiopathic epiretinal membrane (ERM) surgery between three different surgical techniques: ERM peeling only, whole-piece ILM peeling, and maculorrhexis ILM peeling. PATIENTS AND METHODS: This is a retrospective, consecutive, and comparative study enrolling 60 patients from Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Surgery performed between July 2011 and June 2012 was done with ERM peeling only (group I). ERM peeling and ILM peeling as a whole piece (group II) were performed between July 2012 and July 2013. Surgery performed between August 2013 and December 2014 was done with maculorrhexis ILM peeling (group III). Main outcome measures include visual acuity change (BCVA) and central foveal thickness (CFT). RESULTS: At 12 months postoperation, the mean BCVA in group III was significantly better than in group I and group II. Comparison of CFT reduction between the three groups revealed significantly more reduction in group III than in group II at all postoperative follow-up periods. Eyes with restoration of foveal depression were observed in 52.6% in group I, 52.4% in group III, but only 20% of eyes in group II. None of the eyes in both ILM peeling groups encountered recurrence of macular pucker formation. CONCLUSION: All three techniques can achieve visual acuity improvement and macular thickness reduction. Maculorrhexis ILM peeling achieves more rapid improvement of visual function, better final visual outcome, and a higher rate of normal foveal contour than whole-piece ILM peeling.

Cellular cytotoxicity of antiglaucoma drugs in cultured corneal endothelial cells.

In this study, the various antiglaucoma drugs including betaxolol, timolol, levobunolol, carteolol, brimonidine, dipivefrin, dorzolamide, brinzolamide, latanoprost, unoprostone, and pilocarpine were used to investigate the effects of cellular cytotoxicity in cultured bovine corneal endothelial cells. After exposure to the drugs in three dilutions, 1/100, 1/1,000, and 1/10,000, for 100 minutes, cells were estimated based on the release assay of lactate dehydrogenase (LDH) enzyme. It was found that cellular LDH was significantly released in the medium only at 1/100th dilution of betaxolol, brimonidine, dorzolamide, dipivefrin, latanoprost and unoprostone to 130%, 123%, 145%, 157%, 128% and 237%, respectively, compared with controls upon exposure to drugs for 100 minutes. Moreover, benzalkonium chloride preservative at the concentrations ranging from 0.001 to 0.00001 mg/mL did not affect cellular LDH release in bovine corneal endothelial cells. These results indicate that high concentrations of antiglaucoma drugs may induce cytotoxicity in corneal endothelial cells.

Glaucomatocyclitic Crises May Occur in Patients with Narrow or Closed Angles.

PURPOSE: To report cases of glaucomatocyclitic crises and discuss the possibility of occurrence in patients with narrow or closed angles. BACKGROUND: The prevalence of angle closure is much higher among Asians than among the Western population. Currently, there is no evidence for a direct relationship between the etiology and angle structure. DESIGN: A retrospective and observational case series. METHODS: We retrospectively collected data from nine adult patients (three males and six females) who were diagnosed with a glaucomatocyclitic crisis and a shallow anterior chamber over a 21-year period, from 1995 to 2016, at the Kaohsiung Medical University Hospital. A narrow angle was defined as a grade less than the Shaffer system grade II. Ophthalmic examinations, including anterior segment biomicroscopy, direct ophthalmoscopy, intraocular pressure measurements, anterior chamber reaction, visual field tests, and the grade of the anterior chamber angle according to the Shaffer system, were reviewed. RESULTS: These patients experienced at least one typical unilateral ocular hypertensive episode that fulfilled the criteria of a glaucomatocyclitic crisis without the angle feature. All patients had gonioscopically narrow or closed angles with or without peripheral anterior synechiae. CONCLUSIONS: The coexistence of narrow or closed angles and a glaucomatocyclitic crisis is possible, especially in patients of Asian descent. In patients with shallow anterior chambers, a glaucomatocyclitic crisis may be a cause of acute glaucoma episodes.

Modified internal limiting membrane peeling technique (maculorrhexis) for myopic foveoschisis surgery.

PURPOSE: Myopic foveoschisis occurs in 9-34% of highly myopic eyes with posterior staphyloma. The pathogenesis is still not fully understood. But the relative inflexibility of the inner retina and a tangential traction induced inward traction force in the posterior staphyloma are possible mechanisms. Conventional internal limiting membrane (ILM) peeling generally yields good results. However, a postoperative full-thickness macular hole happens in 13-28% of cases. Therefore, this study describes a modified ILM peeling technique named 'ILM maculorrhexis' to minimize the occurrence of postoperative macular hole in patients with foveoschisis. METHODS: This retrospective case review that included 10 eyes of 10 consecutive patients who underwent vitrectomy with ILM maculorrhexis to treat myopic foveoschisis was studied. After surgery, complete ophthalmic examination and SD-optic coherence tomographic examinations were performed 1, 3, 6, 9 and 12 months postoperatively. RESULTS: After surgical intervention, the foveoschisis resolved dramatically in all 10 eyes. The mean central foveal thickness decreased significantly from 840 µ to 273 µ at 12 months postoperatively. Mean LogMAR best-corrected visual acuity improved from 1.04 preoperatively to 0.59 12 months postoperatively. After the follow-up time of at least 12 months, all 10 eyes remained fovea attached, and none of the 10 eyes developed macular hole. CONCLUSIONS: This technique minimizes traction force over the extremely thinned foveal tissue in highly myopic eyes. In the long-term follow-up of at least 12 months, all 10 cases had good anatomic and visual results. But we still need a larger case number and longer follow-up for further evaluation.

Effects of antibiotics and corticosteroid eyedrops on cellular proliferation in cultured human corneal keratocytes.

The purpose of this study is to investigate the effects of antibiotics and glucocorticoid eyedrops, including gentamicin, sulfisomezole, fluorometholone, dexamethasone, and betamethasone, on cellular proliferation in cultured human corneal keratocytes. Human corneal keratocytes were cultured in RPMI-1640 containing 10% fetal bovine serum. Drugs were prepared from original concentrations to 1/10, 1/100, and 1/1,000 dilutions. After exposure to drugs for 100 minutes, cellular proliferation was estimated by [3H]-thymidine uptake. It was found that cellular proliferation in corneal keratocytes was not affected by any of the three dilutions of gentamicin but was inhibited by 1/10 and 1/100 dilutions of sulfisomezole to 82% and 90% of control. [3H]-thymidine uptake values were inhibited to 75% by 1/10 dilution of fluorometholone and by 1/10and 1/100 dilutions of betamethasone to 84% and 86% of control. Meanwhile, cellular proliferation was significantly inhibited by 1/10, 1/100, and 1/1,000 dilutions of dexamethasone to 82%,86%, and 90%, respectively, in comparison with control values. It was demonstrated that commercial eyedrops of glucocorticoids inhibit cellular proliferation in corneal keratocytes, which may modulate the wound healing of corneal stroma.

Effects of antiglaucoma drugs on calcium mobility in cultured corneal endothelial cells.

The aim of this study was to estimate the effects of various antiglaucoma drugs including betaxolol, timolol, levobunolol, brimonidine, carteolol, dipivefrin, dorzolamide, brinzolamide, latanoprost, unoprostone, and pilocarpine on intracellular free Ca2+ ([Ca2+]i) mobility in cultured bovine corneal endothelial cells. Various antiglaucoma drugs were diluted from original concentrations to 1/ 100, 1/ 1,000, and 1/ 10,000. The [Ca2+] mobility was studied by spectrofluorophotometry after loading with the ester of fura-2 (fura-2/AM). It was found that timolol (58 microM and 5.8 microM), levobunolol (171 microM, 17.1 microM, and 1.71 microM), betaxolol (162 microM, 16.2 microM, and 1.62 microM), carteolol (680 microM and 68 microM), dipivefrin (28 microM and 2.8 microM), dorzolamide (616 microM and 61.6 microM), brinzolamide (260 microM), latanoprost (1.1 microM), unoprostone (28.2 microM, 2.82 microM, and 0.282 microM), and pilocarpine (408 micro and 40.8 microM) induced a significant increase in [Ca2+]i. Nevertheless, only brimonidine (68 microM and 6.8 microM) decreased [Ca2+]i concentration significantly. Benzalkonium chloride preservative did not affect [Ca2+]i after addition of 0.001, 0.0001 and 0.00001 mg/mL to cells. These results indicate that all antiglaucoma drugs may affect the physiologic function of corneal endothelial cells through change of [Ca2+]i mobility.

Effects of antiglaucoma drugs on cellular proliferation in cultured human corneal keratocytes.

The purpose of this study was to investigate the effects of various antiglaucoma drugs, including timolol, betaxolol, carteolol, levobunolol, dipivefrin, and pilocarpine, on cellular proliferation in cultured human corneal keratocytes. Human corneal keratocytes were cultured with RPMI-1640 medium containing 10% fetal bovine serum. Antiglaucoma drugs were prepared from original concentrations to dilutions of 1/10, 1/100, and 1/1,000. After exposure to drugs for 100 minutes, cellular proliferation was estimated by [3H]thymidine uptake methodology. It was found that cellular proliferation in corneal keratocytes was inhibited by only a 1/10 dilution of various drugs including timolol, betaxolol, carteolol, levobunolol, dipivefrin, and pilocarpine. The [3H]thymidine uptake values were significantly inhibited to 63%, 18%, 87%, 68%, 55%, and 67% by a 1/10 dilution of the above drugs. However, the cellular proliferation was also significantly suppressed by 0.01 mg/mL of benzalkonium chloride preservative. It is shown that the inhibition of cellular proliferation by high concentrations of antiglaucoma drugs may result from the benzalkonium chloride preservative contained in these drugs.