Expression of the Na(+)-K(+)-2Cl(-)-Cotransporter 2 in the Normal and Pressure-Induced Ischemic Rat Retina

PURPOSE: To evaluate the expression of the Na(+)-K(+)-2Cl(-)-cotransporter 2 (NKCC2) in the ischemic rat retina. METHODS: Retinal ischemia was induced by pressures 90 to 120 mmHg, above systemic systolic pressure. Immunohistochemistry and western blot analysis were performed. RESULTS: NKCC2 is expressed in the normal retina and its expression is increased by ischemia caused by intraocular pressure elevation. NKCC2 immunoreactivity was observed mainly in axon bundles of ganglion cells and horizontal cell processes in the retina. NKCC2 expression continuously increased with a peak value 3 days (to 415% of normal levels) after ischemic injury, and then gradually decreased to 314% of controls until 2 weeks post injury. The mean density of NKCC2-labeled ganglion cells per mm2 changed from 1,255 +/- 109 in normal retinas to 391 +/- 49 and 185 +/- 37 at 3 days and 2 weeks after ischemia, respectively (p < 0.05), implying cell death of ganglion cells labeled with NKCC2. CONCLUSIONS: Taken together, these results suggest that NKCC2, which is expressed in retinal ganglion and horizontal cells, may contribute to cell death by ischemic injury in the retina, although the molecular mechanisms involved remain to be clarified.

Cases of Pseudophakic Pseudoexfoliation in Glaucoma Patients

We present cases of primary open angle glaucoma patients without previous history of pseudoexfoliation who developed pseudoexfoliative materials on the anterior surface of the intraocular lens after cataract surgery. Among 5 unilateral pseudophakic pseudoexfoliation cases, 3 showed a more advanced state of glaucoma in the affected eye. The other 2 cases showed progression of glaucoma in the affected eye after the development of pseudophakic pseudoexfoliation, while the unaffected eyes remained stable. In the latter 2 cases, control of intraocular pressure was difficult, and more glaucoma medication was needed in the affected eye. Pseudophakic pseudoexfoliation in glaucoma patients with no history of pseudoexfoliation syndrome or pseudoexfoliative glaucoma has not been reported. In our cases, the eyes which developed pseudophakic pseudoexfoliation showed a more advanced state of glaucoma, more difficulty controlling intraocular pressure, and faster progression of glaucoma. More observation is needed, but we cautiously postulate that pseudophakic pseudoexfoliation may have a role as a clinical risk factor in the prediction of glaucoma progression.

Analysis of Systemic Factors through Blood Examination in Normal-Tension Glaucoma Patients

PURPOSE: In this study, we evaluated systemic hemodynamic factors of normal tension glaucoma. METHODS: Forty patients with normal tension glaucoma and thirty healthy people were investigated with regard to hemoglobin, hematocrit, RBC count, WBC count, platelet count, fasting glucose, HbA1c, total cholesterol, triglycerides, LDL, HDL, and high-sensitivity C-reactive protein (hsCRP). Also, ET-1 and MCP-1 were measured using enzyme-linked immunosorbent assay kits. RESULTS: The results of the blood examinations showed no statistically significant differences in hemoglobin, hematocrit, RBC count, WBC count, platelet count, fasting glucose, HbA1c, total cholesterol, LDL, HDL, and hsCRP. Only triglycerides showed a statistically significant difference between the groups (P=0.03). The level of serum ET-1 was significantly higher in the normal tension glaucoma group (P=0.007). The results of MCP-1 showed no statistically significant difference. CONCLUSIONS: We conclude that normal tension glaucoma Is associated with an increased level of triglycerides and that the level of ET-1 could be a hemodynamic cause of normal tension glaucoma.

Ganglion Cell Death in Rat Retinaby Persistent Intraocular Pressure Elevation

Glaucoma is characterized by loss of retinal ganglion cells (RGCs) and their axons. Retrograde axoplasmic transport blockade and excitotoxicity were proposed to be a major cause of RGC apoptosis. We conducted this study to characterize the episcleral vessel cauterization glaucoma model in the rat with respect to decreased retrograde axoplasmic flow and subsequent apoptotic RGC death. After episcleral vessels were cauterized in Sprague-Dawley rats, Fluorogold was injected into their superior colliculi by stereotactic method. Retrograde axoplasmic flow and TUNEL-stained apoptotic dead cells were observed microscopically. Elevated intraocular pressure was maintained for up to 6 weeks during follow-up. Retrograde axoplasmic flow to the rat retina was significantly decreased. Apoptotic RGC was selectively TUNELstained in the retina, especially at the ganglion cell layers. We concluded that elevated intraocular pressure caused apoptotic RGC death through retrograde axoplasmic flow blockage. Further studies will elucidate the neuroprotection strategies in glaucoma patients.

Clinical Results of Ahmed Valve Implantation in the Aspects of Complications

PURPOSE: We retrospectively studied the clinical restults of Ahmed valve implantation in the aspects of complications in refractory glaucoma. METHODS: One hundred fourteen eyes of 112 patients who had undergone Ahmed glaucoma valve implantation from February 1996 to April 2002 were reviewed retrospectively. Patients with less than 6 months of follow-up were excluded from the analysis. Etiology of glaucoma, change of intraocular pressure and visual acuity and the incidence of complications were evaluated. RESULTS: Postoperative complications included persistent shallow ant.chamber with hypotony in 10 eyes, choroidal detachment in 11 eyes, hyphema in 16 eyes, vitreous hemorrhage in 3 eyes, suprachoroidal hemorrhage in 2 eyes, valve obstruction in 15 eyes (10 by fibrous membrane, 3 by vitreous, 1 by silicone oil and 1 by gas tamponade), valve malposition in 14 eyes (6 by corneal contact 4 by iris contact or incarceration, 1 by lens contact, 1 by intraocular lens contact and 2 by shortage of valve tip), scleral graft exposure in 2 eyes, conjunctival scarring in 2 eyes, encapsulated bleb in 2 eyes, EOM limitation due to giant bleb in 2 eyes, corneal graft rejection in 1 eye and phthisis bulbi in 10 eyes. Various kinds of complications were observed in 66 eyes of the total 114 eyes. CONCLUSIONS: Ahmed glaucoma valve implantation was effective in controlling intraocualr pressure and maintenance of visual acuity. However, Ahmed valve showed many kinds of complications in the follow-up periods.

Inhibitory Effects of Taxol and Mitomycin C on Proliferation of Cultured Rabbit Subconjunctival Fibroblasts

PURPOSE: Scar tissue formation by proliferation, migration and contraction of fibroblasts may result in the failure of trabeculectomy. The author investigated inhibitory effects of Mitomycin C (MMC) and Taxol on proliferation of cultured rabbit subconjunctival fibroblasts. METHODS: Tenon's fibroblasts of rabbits were cultured and exposed to various concentrations of each drug for 6 days. Cell viability was measured using MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay. RESULTS: Both MMC and Taxol inhibited proliferation of fibroblasts significantly in a dose-dependent manner, with ID50s of 0.27 mg/l and 0.08 mg/l, respectively. CONCLUSIONS: We have confirmed that Taxol is as potent inhibitor of fibroblast proliferation as Mitomycin C. This result may possibly support the use of Taxol in trabeculectomy to improve the success rate of trabeculectomy.

The Relations of Cataract Progressed Postoperatively and Viscoelastic Substance or Mitomycin C used in Trabeculectomy

Viscoelastic substance or Mitomycin C(MMC)is not necessarily used in trabeculectomy. Hence, the authors investigated the rate of cataract development or progression after trabeculectomy related with using of the viscoelastic substance or MMC. The authors evaluated 119 eyes undergoing trabeculectomy and divided these eyes into 4 groups :group 1, 2, 3, and 4. In group 1, viscoelastic substance or MMC was not used(27 eyes). In group 2, only viscoelastic substance was used(35 eyes). In group 3, only MMC was used(15 eyes). In group 4, both viscoelastic substance and MMC were used(42 eyes). The cataract development or progression was examined with slit-lamp biomicroscope at postoperative 6 months and defined as the decrease of visual acuity more than 2 lines. The rate of cataract development or progression at postoperative 6 months was 18%in group 1, 14%in group 2, 40%in group 3, and 19%in group 4.The use of MMC without viscoelastic substance in trabeculectomy influenced cataract development or progression extremely. In conclusion, the results of this study suggest that the viscoelastic substance may reduce the rate of cataract development or progression after trabeculectomy in which MMC is used besides.

Analysis of HRT Heidelberg Retina Tomograph in High Myopic Patient

In high myopic patients with optic disc tilting, reference height is underestimated and many parameters depending on reference height will be changed with previous Heidelberg Retina Tomograph[HRT, under version 1.01].Therefore, care must be taken to classify the patients with tilted optic disc because underestimation of the amount of their cup area and volume may cause faulty decision to normal disc. However, by using "tilted analysis method" in recent HRT program[ver.2.01], we can expect to overcome such problems so, in this study we try to find out how much the HRT results are different between tilted and untilted analysis methods.We evaluated 26 high myopic patients under -6 diopters with tilted optic disc and glaucomatous visual field defects from March 1998 to July 1998. We compared their HRT parameters measured by untilted and then tilted method to each other.The mean reference height was changed from 0.2735 to 0.2892, the cup volume from 0.1961 to 0.1790 and the neural rim volume from 0.3060 to 0.3358 but glaucoma classification, the final conclusion of test, was not changed significantly due to neural rim volume and height variation contour increase with constant cup shape measure. Therefore, although refrence height is lowered and cup volume decreased with HRT[ver.1.01]in high myopic patients, if considering other many parameters, we can interpretate results rightly.

Effect of Cataract Surgery through Clear Corneal Incision in Glaucomatous Eyes with Filtering Blebs

The small-incision cataract surgery by phacoemulsification with foldable posterior chamber lens implantation have recently permitted new options for combined trabeculectomy with cataract extraction. In the present study, we performed phacoemulsification and foldable intraocular lens implantation using small clear corneal incision in 20 patients with 22 glaucomatous eyes who had previously undergone trabeculectomy and determined its effects on visual acuity, intraocular pressure, the number of medications applied, and status of the filtering blebs. The mean follow-up period was 10.1 months and the mean time interval between the two surgeries was 14.7 months. The mean best corrected visual acuity was 0.19 preoperatively and 0.60 postoperatively and the postoperative visual acuity had improved in 19 eyes(86.4%). The mean(+/-standard deviation, SD) preoperative IOP was 16.7+/-5.88 mmHg and the mean(+/-SD) postoperative IOP at final visit was 15.5+/-4.07 mmHg. Postoperatively, the IOPs remained well controlled in 20 eyes(90.9%) without additional ocular hypotensives and required additional medications for control in 2 eyes(9.09%). And the funictioning bleb failures occurred in 5 eyes(22.7%). We found the procedure to be effective in restoring vision while controlling intraoperative pressure and preserving the filtering blebs.

Analysis of Systemic Risk Factorsin Normal Tension Glaucoma

It has been suggested that normal tension glaucoma could be the result of pressure independent factors. One of the current theories is that normal tension glaucoma is the result of decreased optic nerve perfusion on the basis of vascular disease or other systemic factors such as altered blood viscosity or coagulation state. This study compared the vascular viscosity profiles, coagulation tests, and biochemical tests of 30 consecutive cases of normal tension glaucoma with 30 control cases to evaluate association of particular systemic state with normal tension glaucoma in Korean population. The data of total cholesterol and low density lipoprotein (LDL) cholesterol were significantly higher in the normal tension glaucoma group than in the control group. But there were no significant differences between the two groups with respect to the many other factors examined. These results support the vascular ischmic theory due to hyperlipidemia in the pathogenesis of the normal tension glaucoma. Inadequate circulation of optic nerve due to atherosclerotic change might play an important role in the pathogenesis of normal tension glaucoma.

Results of Trabeculectomy on the Glaucoma Associated with Keratoplasty

To evaluate the effect of trabeculectomy on glaucoma following penetrating keratoplasty, we analyzed surgical results of patients who had taken trabeculectomy because of glaucoma associated with penetrating keratoplasty during the last two years. We evaluated success rate of trabeculectomy and possible causative factors which evoked filtering surgery failure. Mean follow-up period was about one year (11.98+/-3.2months) after trabeculectomy. Among the eyes with trabeculectomy, 61.9% maintained their intraocular pressure below 21 mmHg until last visit. Early elevation of increased intraocular pressure after keratoplasty was the only risk fator of filtering surgery which was stastically significant (P<0.05). However, aphakic or pseudophakic eyes, eyes with inflammatory disease and large donor trephine size were also estimated for possible risk factors. Corneal graft failure was single most common complicagion (5 eyes, 23.9%) after trabeculectomy. In conclusion, we think that early filtering surgery on the glaucomatous eyes associated with keratoplasty possible improved the surgical results. However, further studies to increase success rate of filtering sugery and to reduce graft failure rate, were warranted.

A Case of Total Vitrectomy in Aphakic Refractory Glaucoma with Prior Keratoplasty after Ahmed Glaucoma Valve Implantation

Aqueous drainage devices have been used to treat refractory glaucoma with poor prognosis, but it has been described with valved implants and non-valved implants that their complications are hypotony, shallow anterior chamber, hyphema, suprachoroidal hemorrhage, endothelial touch by tube and the blockage of tube with fibrin, iris or vitreous. We used the Ahmed galucoma vlave implant to control the intraocular pressure in the aphakic eye with prior penetrating keratoplasty. Although the blockage of tube with vitreous was developed in first postoperative day, we successfully removed that blockage by total vitrectomy.

Risk Factors for Glaucoma Filtering Surgery and Mitomycin C

To determine the factors which can increase the failure after glaucoma filtering surgery and to evaluate the affect of Mitomycin C(MMC) on filtering surgery. We evaluated 249 eyes who underwent glaucoma filtering surgery consecutively during last 2 years in Catholic University Medical College hospitals. 129 eyes had risk factors and 68 eyes of them were treated with MMC during operation. The success rate of the group with risk factors was significantly lower (P=0.001) than that of the group without risk factors. In the risk group, MMC has increased the sucess rate (P=0.07). Previous cataract surgery, neovascularization of iris (NVI) , re-trabeculectomy, young age under 40, uveitis and diabetes were significant risk factors for surgical failure. After adjustment of each factors, previous cataract surgery, NVI, retrabeculectomy and young age still increased the failure rate significantly. Among them we were able to make reduse the effect of re-trabeculectomy and youth by using MMC during surgery. The outcome of glaucoma surgery may increase the success rate in some high risk cases.

Two Cases of Iridoschisis

Iridoschisis is a very rare condition occurining in either sex, usually bilaterally. Glaucoma occurs in approximately 50% of the cases, and other ocular defects may be present in iridoschisis. It is considered as a degenerative process related to senescene. We experienced two cases of typical iridoschisis and report the cases with a review of the literature because iridoschisis is not reported yet in our country.

The Effect of 1 % Apraclnidine on Intraocular Pressure Following Argon Laser Iridotomy and Laser Trabeculoplasty

We studied the effect of 1% apraclonidine (Iopidine(R)) on the ocular hypotensive action and its ocular side effects following laser surgery for glaucoma. One hundred twenty patients with primary angle closure glaucoma underwent argon laser peripheral iridotomy and 40 patients with primary open angle glaucoma were treated with laser trabeculoplasty. Mean lOP of eyes instilled with 1% apraclonidine fell by 16% 3 hours after instillation in laser iridotomy cases and by 28% 3 hours after instillation in trabeculoplasty cases. lOP elevation greater than lO mmHg was found in 18 eyes (30%) of the control group in iridotomy cases and 4 eyes (40%) in trabeculoplasty cases, but none in the apraclonidine group in both treated cases for the first three hours. Apraclonidine reduced the incidence and magnitude of potentially harmful lOP elevations after laser irdotomy and trabeculoplasty.

Trabeculectomy in Low-tension Glaucoma

I analyzed the changes of visual function of 49 eyes of 38 patients with low-tension glaucoma (LTG) who underwent trabeculectomy and had been followed for at least 3 years at Wills Eye Hopsital. The results were as follows: 1. Average IOP was 18.1 mmHg preoperatively and decreased by 5.0, 4.9 and 4.4 mmHg respectively at 1, 3 and 5 years postoperatively. 2. Postoperative visual acuity decreased in 9 eyes (23%) and 7 eyes (35%) respectively at 3 and 5 years. 3. Postoperative visual field improved in 18 eyes (42%) and 5 eyes (22%) respectively at 1 and 5 years. However it progressed in 9 eyes (23%) and 9 eyes (39%) respectively at 3 and 5 years. 4. In terms of postoperative complications, choroidal detachment developed in 3 cases (6%), cataract requiring extraction in 11 cases and there were no cases requiring reoperation during 3 years after operation. From these results, whereas lOP decreased continually by 25% for 5 years, visual field progressed in 39% of cases at 5 years. However in light of low rate of both complication and reoperation together with high visual field improvement, if LTG persists despite medication, trabeculectomy is recommended to stop the progression of visual field.

Treatment of Choroidal Detachment After Trabeculectomy

Choroidal detachment has frequently been found to be a complication following trabeculectomy. However there remain many controversies about the indication and the timing as to when to perform choroidal drainage. Of 131 cases of trabeculectomy from July 1990 to to June 1991 choroidal detachment was developed in 5 eyes of 4 patients with glaucoma. Among them, 2 cases were treated medically and 3 cases surgically. We classified anterior chamber depth according to grading system and made it the guideline for treatment. As choroidal detachment developed, we used medical therapy including more frequent topical application of cycloplegics and steroids, and observed anterior chamber reformation. When grade III anterior chamber the situation where central cornea touches on lens surface persisted 12 to 24 hours, we performed anterior chamber reformation, sclerotomy and choroidal drainage During the follow-up period (mean, 7 months), all cases except one were controlled without medication, but 1 case developed hypermature cataract 1 month after choroidal drainage, with increased intraocular pressure and conjunctival bleb disappeared. Once choroidal detachment develops, rapid medical treatment is necessary. If medical therapy fails, prompt surgical reformation of the anterior chamber along with drainage of any suprachoroidal fluid is needed in grade Ill anterior chamber.

Comparison of the Noncontact Tonometer with Goldmann Tonometer

Several kinds of non-contact tonometers have been used since the first non-contact tonometer was introduced in the 1970's in order to measure intraocular pressure with easiness and accuracy. However several problems were still remained because of:he inaccuracy of the non-contact tonometer in high and low range of intraocular pressure. A new non-contact tonometer (Model CT-20, Japan) was recently introduced by Topcon Company to evaluate the clinical efficacy of the non-ccntact tonometers. The authors measured the intraocular pressure with Topcon tonometer, AO tonometer and Pulsair non-contat tonometer and compared the results with those measured with Goldmann tonometer. The results were as follows: 1) The correlation coefficient between Goldmann and Topcon tonometer was 0.8452 (p=0.001), Goldmann and Pulsair tonometer was 0.7084 (p=O.OOl) and Goldmann and AO tonometer was 0.6048 (p=O.OOl) in the normal eyes. 2) The correlation coefficient between Goldmann and Topcon tonometer was 0.8651 (p=0.0001) in the ocular hypertensive or open angle glaucoma eyes. 3) The correlation coefficient between Goldmann and Topcon tonometer was 0.6987 (p=0.000l) in the low lOP eyes. 4) The correlation coefficient between Goldmann and Topcon tonometer was 0.6829 (p=0.0001) in the high myopic eyes. As above, a new-contact tonometer (Model CT-20, Japan) made by Topcon Company was relatively accurate in measuring not only the intraocular pressure of normal eyes but that of ocular hypertensive, low IOP and high myopic eyes.

Changes of Corneal Endothelium and Surrounding Tissues After Implantation of IOLAB-IOL and UNI-IOL in Rabbit's eyes

The aim of this study was to evaluate the degree of tolerance of the rabbit's eye when UNI-IOL, prototype of posterior intraocular lens, manufactured in Korea was implanted into the rabbit's eye in comparison with that of the rabbit's eye when IOLAB-IOL manufactured in U.S.A. was implanted. Twenty two eyes of 22 rabbits were operated with extracapsular lens extraction using Healon(R). IOLAB-IOL was implanted into the 11 eyes(Group 1) while UNI-IOL was implanted into another 11 eyes(Group 2). Clinical observation was performed for 5 months and corneal thickness and endothelial cell density were measured. Several eyes were enucleated and their ultrastructural changes were observed with light and electron microscopes. The results are as follows: 1. Clinical observation by slit lamp biomicroscope revealed that inflammatory reaction in the anterior chamber in group 1 and 2 decreased gradually until post operative 10th day and almost disappeared by the post-operative 14 th day. With regard to postoperative complication, there were 2 cases of hyphema in group 1 and 1 case in group 2 and 1 case of wound leaking in group 2 in the early stage. In the later stage, 2 cases of posterior synechia in each group and 1 case of anterior displacement of optic of PCL in group 2 were observed. 2. Corneal thickness of group 1 and 2 increased by 33.5% and 35.9% respectively on the postoperative 1st day and increased most on the postoperative 3 rd day. Then it began to decrease and reached the level of 17.2% and 21.7% respectively on the postoperative 7th day. After 28 days after the operation it decreased to 5.5% and 7.7%, 3 months after the operation 1.5% and 2.4% and 5 months after the operation 1.3% and 2.1% which are almost normal levels. 3. Decreasing rate of endothelial cell density in group 1 and 2 showed 20.2% and 22.7% on the post-operative 4th day, 5.3% and 5.2% on the postoperative 28 th day, 2.8% and 2.7% after 3 months and after 5 months 1.5% and 1.3% respectively. 4. The changes in the corneal thickness and loss of endothelial cell density were not significant statistically between group 1 and 2. 5. Light microscopic finding showed mild chronic inflammatory infiltrates in the stroma of iris and ciliary body in both groups. 6. Scanning electron microscopic finding showed normal hexagonal cell shape with some edema in both groups on the postoperative 14th day while both groups showed normal cell shape without edema 28 days, 3 months and 5 months after the operation. 7. Transmission electron microscopic finding showed no changes in internal structure of endothelial cells 14 days, 28 days, 3 months and 5 months after the operation. In conclusion, the implantation in rabbits eyes of the UNI-IOL showed little difference in clinical and histopathologic findings compared with that of IOLAB-IOL and was well tolerated.

The Change of the Corneal Curvature After Cataract Extraction

The changes of corneal curvatures were measured in 63 cataract cases before and 2 months after cataract extraction with the aid of ophthalmometer and photo keratoscope. The change of the cornea in the vertical curvature was shown to be greater than that of horizontal curvature, in cases of conventional large corneal incision(120-170 degrees) of cataract surgery. Vertical curvature of the cornea was decreased and horizontal curvature was increased. The corneal astigmatism before and 2 months after surgery were respectively 0.67D. and 1.56D. showing the difference of 0.89D.