Analysis of Systemic Risk Factors in Idiopathic Macular Hole

PURPOSE: We studied the association between systemic risk factors and idiopathic macular hole. In addition, we analyzed the mechanism by which systemic risk factors affect the development and progression of macular hole. METHODS: Seventy patients with idiopathic macular holes were compared with 30 sex- and age- matched controls. The vascular viscosity profiles, and coagulation, biochemical and hormone factors were evaluated as systemic risk factors. RESULTS: The levels of fibrinogen and blood estrogen were significantly higher in the idiopathic macular hole group than in the control group. Also the fibrinogen level increased with the progression of macular hole. But there was no significant difference between the two groups with respect to the remaining factors. CONCLUSIONS: These results support the possibility that fibroproliferative factors from platelet increase in patients with idiopathic macular hole, and that fibrinogen is the parameter that increases among the fibroproliferative factors. This study also suggests that blood estrogen is important in the development of macular hole.

Effect of Basic Fibroblast Growth Factor-Saporin (bFGF-SAP) Conjugate on Bovine Choriocapillary Endothelial Cells

We evaluated the effect of a basic fibroblast growth factor (bFGF) and saporin conjugate (bFGF-SAP) on proliferation, migration and tubule formation in bovine choriocapillary endothelial cells (BCECs). Cell proliferation and MTS assays were done with 0.01, 0.1, 1, 10, and 100 nM bFGF-SAP, and an equimolar concentration of bFGF and saporin. TUNEL assay was performed to confirm apoptosis. Cells were treated with 1, 10, and 100 nM bFGF-SAP and migration assay and tubule formation assay were done. Results were evaluated with image analysis. All experiments were performed in triplicate and repeated three times. Viable cells (ID50 = 0.62) and cell proliferation by MTS assay (ID50 = 0.75 nM) were inhibited. Saporin caused cytotoxicity and inhibition of proliferation at high concentration. DNA fragmentation was identified by TUNEL assay. Migration and tubule formation were also inhibited. All mechanisms responsible for neovascularization were inhibited, and this could be applied in the management of subretinal choroidal neovascularization (SRN).

Comparison of Surgical Results for Idiopathic Macular Hole: Fluid-Gas Exchange vs. Fluid-Air Exchange

PURPOSE: In pars plana vitrectomy for macular hole, internal limiting membrane (ILM) peeling, fluid-gas exchange, prone position for more than one week are generally needed. However, the authors modified these surgical procedures. After vitrectomy, we performed ILM peeling with Indocyanine green (ICG) dye and fluid air exchange and kept the patient prone position for one day. We then compare the clinical results and analyze possible factors affecting surgical outcomes. METHODS: Data were reviewed from a retrospective study on Group I, form whom vitrectomy, fluid gas exchange, and ILM peeling without ICG were completed, and on Group II, for whom vitrectomy, fluid air exchange, and ILM peeling with ICG were completed. We evaluated the anatomical and functional success statistically. RESULTS: The anatomical success rate was 79% and 94% and the functional success rate was 42% and 88% in groups I and II respectively. Furthermore, preoperative visual acuity significantly affected the visual outcome. CONCLUSIONS: Without having to maintainl face-down position for a long time, successful anatomical and functional outcomes were obtained through fluid air exchange and prone position for one day. This result suggests that complete ILM peeling with ICG shortens the required duration of tamponade and allows for less stringent maintenance of face-down position.

Hydrogen Peroxide-Induced Cell Death in a Human Retinal Pigment Epithelial Cell Line, ARPE-19

The loss of retinal pigment epithelium (RPE) with aging is related to age-related macular degeneration (AMD). This study was conducted to investigate the mechanism of hydrogen peroxide (H2O2) induced cell death in a human retinal pigment epithelial cell line, ARPE-19. Hydrogen peroxide was added at different concentrations to ARPE-19 cells and cultured. The cytotoxicity was assayed by mitochondrial function using 3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenyl tetrazolium bromide (MTT) testing. The patterns of cell damage were assessed using an acridine orange-ethidium bromide differential staining method, in situ end labeling (ISEL) assay and transmission electron microscopy (TEM). Catalase, a major antioxidant, was used to prevent cell death. The cleavage of procaspase 3 and poly (ADP-ribose) polymerase (PARP) was determined by western blot analysis. Hydrogen peroxide significantly induced cell death in ARPE-19 cells, whereas pretreatment of the cells with catalase prevented cell death. Application of the ISEL assay and acridine orange/ethidium bromide staining demonstrated that the H2O2-induced cell death occurred by an apoptotic mechanism at lower concentrations of H2O2 (400, 500, 600 microM), whereas higher concentrations of H2O2 induced necrosis rather than apoptosis. Caspase 3 was associated with the apoptotic pathway in human RPE cell death. Western blot analysis confirmed caspase 3 activation and cleavage of substrate proteins in ARPE-19 cells treated with an H2O2 concentration of 600 microM. These results indicate that treatment with H2O2 induces apoptotic and necrotic cell death in ARPE-19, and that caspase 3 is associated with apoptotic cell death. Therefore, H2O2 may induce the destruction of RPE cells in AMD by the combined effects of apoptosis and necrosis.

Two years results of surgery for idiopathic macular hole

PURPOSE: To evaluate preoperative and intraoperative factors affecting the clinical results and determine the effectiveness of the internal limiting membrane in surgery for long standing idiopathic macular holes (stage 2, 3, 4). METHODS: The data were reviewed from a retrospective study on 95 consecutive eyes with idiopathic macular holes undergoing vitrectomy, fluid gas exchange. Forty six of the 95 eyes underwent internal limiting membrane removal surgery additionally. Postoperative follow up was for 2 years. Wilcoxon matched pairs test, Wilcoxon rank test and multiple regression analysis were performed by using SPSS program. RESULTS: The surgery was anatomically successful in 74 of the 95 eyes (77.8%) and 30 of the eyes (31.5%) showed functional success. Preoperative visual acuity and internal limiting membrane removal were important factors affecting postoperative visual outcome in 2 years follow up of the vitrectomy for idiopathic macular holes. Preoperative factors such as age, sex, duration of visual complaints, stage were not found any association with postoperative visual acuity. CONCLUSIONS: Preoperative visual acuity and internal limiting membrane removal were good prognostic factors in idiopathic macular hole surgery. Functional success group showed constant improvement of visual acuity in postoperative 2 years.

Serum factors associated with neovascular glaucoma following vitrectomy for proliferative diabetic retinopathy

We performed a retrospective study of serum factors associated with neovascular glaucoma that can occur following vitrectomy for proliferative diabetic retinopathy. The medical records of 183 patients (241 eyes) who received vitrectomy between August 1996 and August 2000 were studied retrospectively and subsequently analyzed by linear logistic regression analysis and multiple logistic regression tests. Neovascular glaucoma developed at an average of 2.7 months in 31 of 241 eyes (14.1%). The overall anatomical success rate of retinal attachment was 82.5% (199 eyes in 241 eyes), although it decreased to 45.1% (14 eyes in 31 eyes) in eyes with neovascular glaucoma. Serum cholesterol (P = 0.041) and fibrinogen levels (P = 0.020) were significantly associated with the development of neovascular glaucoma. However, no significant association could be found concerning hypertension, diabetic retinopathy or hypercholesterolemia (P > 0.05). We suggest that serum creatinine, cholesterol and fibrinogen levels can be used to predict the development of neovascular glaucoma in vitrectomized eyes with diabetic retinopathy and can further provide a more active approach to preventing the development of this condition.

Neodymium: YAG Laser Discission of Postoperative Pupillary Membrane: Peripheral Phtodisruption

PURPOSE: To treat pupillary membrane which developed after cataract operation and vitrectomy,steroid eye drops with mydriatics or, in sever case, tPA has been used. However steroid eye drops needs prolonged treatment and tPA has many complications such as, infection, or hemorrhage. We tried to remove pupillary membrane with Nd-YAG laser by using peripheral quadrantic disruption technique. METHODS: We treated 8 eyes from Jan. 1996 to Oct. 1999, and observed within 24 hours following Nd-YAG laser treatment. The pupillary membrane was cut with Nd-YAG laser and subsequently absorbed within 24 hours. RESULTS: There was no such complicaitons, as increased IOP, hemorrhage, and IOL damage. Immediately after Nd-YAG laser, visual acuity was improved and fundus was examined. CONCLUSION: Therefore we recommend Nd-YAG laser membrenectomy in cases of pupillary membrane, which did not respond to steroid therapy.

Effect of the Superior Cervical Sympathectomy on Experimental Retinal Branch Vein Occlusion in Rabbits

PURPOSE: Superior cervical sympathectomy was performed on argon laser induced experimental branched retinal vein occlusion in rabbits to evaluate its effect on retinal blood flow. METHODS: Branched retinal vein occlusion (BRVO) was induced by argon laser in 30 eyes (15 pigmented rabbits) divided into three groups. One and 3 weeks after inducing BRVO, superior cervical sympathectomy was performed in Group 1 (early) and 2 (late), respectively. Group 3 was left as a control group. Fundus photography, fluorescien angiography and Heidelberg Retinal Flowmetry (HRF) were performed prior to and after sympathectomy. Pathologic examination was done after enucleation. RESULTS: The sympathectomy groups, especially Group 1 (early), showed better recovery of retinal blood flow, volume, and velocity. CONCLUSIONS: Sympathetic block appears to produce dilatation of the retinal blood system, and we suggest stellate ganglion block technique as an effective treatment modality on human beings with BRVO.

The Function of Cytokines in Several Vitre oretinal Diseases

Many cytokines are known as inducing or aggravating factors in several vitreoretinal diseases. Especially transforming growth factor-beta(TGF-beta), basic fibroblast growth factor(bFGF)and vascular endothelial growth factor(VEGF)are implicated in proliferative diabetic retinopathy(PDR), proliferative vitreoretinopathy(PVR)and many other vitreoretinal diseases . The aim of this study is to analyze the an aggravating roles of cytokines in the pathogenesis of vitreoretinal disease. We analyzed levels of TGF-beta1, TGF-beta 2, bFGF and VEGF in vitreous of 82 patients with several vitreoretinal diseases. Vitreous samples were obtained using vitrector as dry vitrectomy and levels of TGF-beta1, TGF-beta2, bFGF and VEGF were determined by ELISA. The level of VEGF was higher only in PDR group. But in the rest of conditions, no changes in any cytokine level was detected. On clinical situation, the higher level of VEGF was found in group with vitreous hemorrhage, retinal neovascularization and vitreoretinal fibrosis. The level of VEGF was lower in the eyes with preoperative panretinal photocoagulation . In the eyes with vitreoretinal fibrosis, the level of TGF-beta2 is lower, whereas the level of VEGF is higher. These results supports that VEGF is one of the important angiogenic and proliferative factors and when increased, induce vitreous hemorrhage. Our study also suggests the possibility that increased TGF-beta2 may play a role in the regression of proliferation.

Neurotropic Effect of Basic Fibroblast Growth Factor on Laser Wound

In order to analyze the potential role of basic fibroblast growth factor (bFGF)on retinal wound after laser photocoagulation, we studied the expression of GFAP and the morphologic changes in the retina of pigmented rats. A multiline krypton laser was used to produce laser lesions. After irradiation, eyes were intravitreally injected with 1 microliter vehicle or 1 microgram of bFGF in l microliter of vehicle. And we examined the expression of GFAP at 1 day, 3 days, 7 days and 14 days after treatment.We also measured the size of defect in outer nuclear layer at 7 days after laser. The results were as follows : 1. GFAP immunoreactivity of M ü ller cell begins to appear within 24 hours in whole retina area.It sharply increases until 7 days and then decreases slowly. 2. bFGF stimulates the expression of GFAP and it is statistically significant(p<0.05) 3. BFGF prevents cell death of photoreceptor in the laser lesions(p<0.05 ) From these results, we concluded that bFGF stimulates Müller cell reactivity after laser phtocoagulation and prevents photoreceptor loss. These results may be important to understand the healing mechanism of laser phtocoagulation and to minimize the complications of laser phtocoagulation.

Macular Hemodynamics before and after Retinal Photocoagulation in Branch Retinal Vein Occlusion using Heidelberg Retina Flow meter(HRF )

To investigate the pathogenesis of macular edema in branch retinal vein occlusion(BRVO)and its attributing factors, we measured the macular circulation using HRF(Heidelberg Retina Flowmeter)before, 1 hour, 1 day, and 1 month after grid laser photocoagulation in 12 patients. After laser photocoagulation, the macula circulation significantly increased in 8 eyes(group 1), and remained unchanged in 4 eyes(group 2). Mean postoperative macular circulation of group 1 was blood volume 136.2%, blood flow 148.0%, and blood velocity 144.4%. And mean postoperative macular circulation of group 2 was blood volume 103.8%, blood flow 97.8%, and blood velocity 98.8%. The mean age of the patient was higher in group 1(group1:mean age 59.0, group 2:mean age 43.5, p=0.0008)and the interval between the onset of BRVO and photocoagulation was longer in group 1 than in group 2(group 1:12.4 months, group 2:4.3 months, p=0.0233). Our results suggest that retinal autoregulation may play an important role in the resolution of macular edema in BRVO after grid photocoagulation. Therefore the evaluation of retinal autoregulation using HRF is important in determining the treatment guide line and the prognosis of photocoagulation.

The Analysis of Clinical Results Following Vitrectomy for Diabetic Retinopathy

The objective of this research is to examine the visual outcome of diabetic vitrectomy depending on each indication, to examine the factors influential to last visual acuity, to identify the causes for low vision and to learn the frequency of postoperative complications. Risk factors for the development of neovascular glaucoma either preoperative or intraoperative were carefully evaluated. Postoperative visual improvement was achieved in 67 eyes[53.6%]of 97 patients[125 eyes]who had undergone surgery due to diabetic retinopathy. Anatomical success was achieved in 111 eyes[88.8%]and vision better than 5/200 in 54 eyes [43.2%]. Statistically significant improvement of vision was obtained among the patients who had been controlling their blood sugar level successfully. Postoperative complications such as rubeosis iridis or neo-vascular glaucoma proved to be detrimental to visual outcome. Neovascular glaucoma occured in 20 eyes among the total 125 eyes[16%]and more frequently associated in eyes with postoperative retinal detachment[37.5%]than in eyes without retinal detachment[12.8%]. The difference was significant statistically. To summarize :first, thorough control of blood sugar level is indispensible in order to reduce postoperative visual loss and obtain the maximum effect of diabetic vitrectomy, second, postoperative occurrence of retinal detachment is at high risk for developing neovascular glaucoma.

Assessment of Idiopathic Macular Hole Surgery by Heidelberg Retina Tomograph

For the evaluation of preoperative and postoperative factors effecting the results of vitrectomy as a treatment of full thickness macular hole, we estimated the three dimensional morphology of macular hole using the HRT [Heidelberg retina tomography]and investigated every patient's history and operation method. Pars plana vitrectomy, epiretinal and internal limiting membrane removal, and C3F8 injection were performed in 19 patients[19 eyes]with full thickness macular holes. Anatomic success was seen in 12 eyes[63.2%]and was statistically related with preoperative hole area, volume and depth. Functional success was seen in 6 eyes[31.6%]and was significantly related with preoperative hole volume and depth, marginal detachment area and volume, hole diameter and hole area. In addition, anatomic success was statistically related with internal limiting membrane removal[p<0.01], stage and preoperative visual acuity [p<0.05]. Functional success was significantly related with preoperative visual acuity, internal limiting membrane removal[p<0.01], stage and duration of the disease[p<0.05]. We conclude that preoperative HRT is a useful method in deciding the operative indications and also in predicting the outcomes.

Measurement and Analysis of Neurosensory Retinal Detachment in Central Serous Chorioretinopathy Using Heidelberg Retina Tomograph

No Abstract Available.

The Analysis of Factors Affecting the Corneal Endothelial Cells during Vitrectomy

No Abstract Available.

The Role of VEGF and Bruch's Membrane in the Development Choroidal Neovascularization

A major cause of blindness in elderly people is choroidal neovascularizapathogenesis and stimulating factor of CNV is not clearly understood. Vascular endothelial growth factor(VEGF)is a major stimulating factor for retinal neovascularization in ischemic retinopathy such as diabetic retinopathy, retinopathy of prematurity. But it is not known if VEGF is a stimulating factor for CNV. In this study, we have treated VEGF transgenic mice and C57BL/6 mice with laser. Different laser parameter for damage to retina pigment epithelium(RPE)only and for break of Bruch's membrane were used each. We were not able to induce CNV with only RPE damage. CNV wes induced when the break of Bruch's membrane was made and there was profuse CNV in VEGF transgenic mice rather than C57BL/6. These data suggest that the damage of Bruch's membrane may be the prerequisition for CNV formation and VEGF is the important stimulating factor for CNV.

Result of Surgery for Epiretinal Membrane and Their Recurrence

We retrospectively reviewed the medical records of 25 cases of removal of macular epiretinal membrane who had been treated by vitrectomy. Indication for vitrectomy was decreased central vision less than 20/60, metamorphopsia or progressive decreased vision (more than 2 lines on Snellen chart) during 6 months.Preoperative and postoperative examination include best corrected visual acuity, biomicroscopic fundus examination with contact and other routine ocular examination.A standard three port pars plana vitrectomy with removal of membrane was performed in all cases, and the lens was removed when necessary.The average follow up period was 12.9 +/-8 . 4 months.Nineteen of 25 eyes (76%)showed a postoperative visual improvement of two lines or more on Snellen chart.Postoperative visual acuity was improved more than 20/40 in 10 of 25 eyes (40%).Postoperative complications were recurrence of uveitis in 3 eyes, progressive cataract in 6 of 14 phakic eyes and recurrent epiretinal membrane in 1 eye.This study demonstrates that vitrectomy for macular epiretimnal membrane results in the overall favorable visual prognosis without serious complication.

E ffects of Vitamin E, Selenium and Zinc Sulfate on Superoxide Release from Human Polymorphonuclear Leuko cytes and Cultured Bovine Retinal Pigment Epithelial Cells

To evaluate antioxidative effect of vitamin E, selenium and zinc sulfate on release of oxygen free radicals from polymorphonuclear leukocytes[PMNs], I measured the amount of superoxide release from human PMNs stimulated by phorbol myristate acetate[PMA]with addition of some antioxidant and antioxidative micronutrients using superoxide-dependent cytochrome c reduction.And to determine a protective effect of them on cultured bovine retinal pigment epithelial cells [RPE]from oxygen radicals, I measured a viability of bovine RPE using MTT assay after incubation with human PMNs and PMA. Vitamin E, selenuim and zinc sulfate are utilized at different concentrations of 1, 10 and 20 microM. Vitamin E and zinc sulfate inhibited superoxide production from PMNs stimulated by PMA from 10 microM concentration gnificantly. But in case of selenium, significant antioxidative effect was not found at each concentration.The antioxidative effect on cultured bovine RPE was evaluated using MTT assay.Among antioxidant and antioxidative micronutrients tested, vitamin E and zinc sulfate inhibited free radical damage to bovine RPE, they increased cell survival rate on culture at concentration of 1, 10 and 20 microM. In contrast, selenium did not increase cell survival rate significantly. With these results, it was found that vitamin E and zinc sulfate had antioxidative effect against superoxide release from PMNs and also protective effect of bovine RPE from free radical damages.Recent studies supported that peroxide may play an important role in causing tissue damage in human and experimental models of ocular inflammation and possibly in Behcet`s disease.It was suggested that antioxidant vitamins and minerals like vitamin E or zinc sulfate might be useful for management and/or prevention of these conditions.

The Relationship between Plasma PAI-1 Antigen Concent ration and Diabetic Retinopathy in NIDDM Patients

To examine the relationship between plasma plasminogen activator inhibitor-1[PAI-1]antigen concentration and diabetic retinopathy in non-insulin dependent diabetic patients, PAI-1 antigen levels and some fibri-nolytic parameters were studied in 89 non-insulin dependent diabetic patients[mean age 59.8 +/-11.3 years]and 25 normal adults as control[meanage 52.8 +/-14.7 years]. The diabetic patients were classified as three subgroups: no DR[n=34], NPDR[n=29]and PDR[n=26]according to the degree of retinopathy.The PAI-1 antigen concentration was measured by enzyme immunoassay[Innotest PAI Ag kit].The diabetic patients had a significantly higher mean PAI-1 antigen level [34.56 +/-17.80ng/milliliter ]compared to a control group[20.35 +/-15.78 ng/milliliter ][p<0.05].Plasma PAI-1 antigen level was significantly lower in diabetic patients with PDR[27.39 +/-15.54 ng/milliliter ]than in diabetics with no DR[36.87 +/-23.31 ng /milliliter ]or NPDR[39.43 +/-2 0.17 ng/milliliter ][p<0.05], probably because of more extensive systemic endothelial damage. These results support the hypothesis that impaired fibrinolysis due to elevated PAI-1 is associated with the development of retinopathy, and therefore the levels of PAI-1 can be used as useful indicator for the development and progression of proliferative retinopathy.

Clinical Effect of Nd -YAG Synechiolysis

Patients who had posterior synechiae associated with uveitis,IOL mplantation, vitrectomy, underwent Nd-YAG synechiolysis had been treated with topical corticosteroids and surgical iridectomy. Even minimal dilatation of the pupil by Nd YAG synechiolysis enable the patient to read and the surgeon to postpone cataract surgery and evaluate optic disc or fundus. Also, pupil block may be treated by detaching the synechiae.18 Patients (20 eyes) with posterior synechiae underwent Nd-YAG synechiolysis at Kangnam St.Mary's Hospital from November 1997 to August 1998. An average of 17.14 +/-6.43mJ laser were used. The average prelaser pupil size was 3.78 +/-0.98 mm ;postlaser, 5.13 +/-1.27 mm.This change was statistically significant (p<0.01). Microhyphema and pigment dispersion developed in 4 eyes. However,no significant long-term complications occurred, and there were no obvious lenticular damage and pupil abnormality. Because this laser treatment is relatively safe and offers some possibility of visual improvement, we recom-mend Nd-YAG synechiolysis,but only if performed by an experienced laser microsurgeon.