Filtering Bleb Size in the Early Postoperative Period Affects the Long-term Surgical Outcome after Trabeculectomy

Purpose@#To investigate whether postoperative filtering bleb size affects the surgical outcome after trabeculectomy. @*Methods@#In this study, we retrospectively reviewed 145 medically uncontrolled glaucoma patients with intraocular pressure (IOP) values >21 mmHg before surgery and data from ≥2 years of follow-up. Postoperative IOP, filtering bleb size including extent and height, and other clinical factors were measured after trabeculectomy. We divided bleb extent into quadrants and bleb height by 0.5 intervals of corneal thickness. The main outcome measure was surgical success. We confirmed complete success when the IOP was ≤21 mmHg and decreased by >20% from baseline without medication or additional procedures. Qualified success used the same criteria but allowed for medication or additional procedures. Cases with reoperation or two consecutive IOP measurements <6 mmHg were considered failures. @*Results@#A total of 145 eyes of 145 patients was included. The average observation period was 30.8 ± 10.9 months. During multivariate Cox regression analysis, a larger extent of filtering bleb revealed significantly low hazard ratios in both complete and surgical success (0.509 and 0.494, respectively); however, there was no significant relationship between bleb height and surgical outcome. @*Conclusions@#The extent of the filtering bleb was associated with surgical outcomes of trabeculectomy in glaucoma patients.

Late-onset Endophthalmitis Caused by Streptococcus Cristatus after Trabeculectomy

Purpose@#To report a case of late-onset bleb-associated endophthalmitis caused by streptococcus cristatus (S. cristatus) after trabeculectomy.Case summary: A 59-year-old woman presented with left ocular pain and visual disturbance. She had undergone trabeculectomy of the left eye 2 years ago. At the initial visit, she was only able to count fingers from the left eye. Whitish thin bleb, conjunctival injection, and inflammation were observed in the left anterior chamber, and the fundus could not be visualized. Despite administering topical and systemic antibiotics, the chamber reaction worsened, and hypopyon and inflammatory membrane were noticed the next day. Vitrectomy with phacoemulsification and intravitreal antibiotic injection was performed, and the intravitreal antibiotic injections were repeated over the next two days. Bacterial culture of vitreous fluid showed a growth of S. cristatus 5 days after the surgery, and inflammation improved after 7 days. One month later, she was still only able to count fingers from the left eye, but there were no signs of endophthalmitis. @*Conclusions@#Postoperative endophthalmitis after glaucoma filtering surgeries caused by S. cristatus has not been reported previously from Korea. To the best of our knowledge, this is the first Korean case of late-onset bleb-associated endophthalmitis caused by S. cristatus. If gram-positive cocci are grown in samples from the patients with endophthalmitis after trabeculectomy, resident oral microflora such as S. cristatus should be considered as the causative pathogen.

Fluid Dynamics of Small Diameter Tubes Used in Membrane-tube Type Glaucoma Shunt Devices

PURPOSE: To investigate the outflow characteristics of silicone tubes with intraluminal stents used in membrane-tube (MT) type glaucoma shunt devices. METHODS: The silicone tubes used in MicroMT (internal diameter of 100 µm with a 7-0 nylon intraluminal stent) and Finetube MT (internal diameter of 200 µm with a 5-0 nylon intraluminal stent) were connected to a syringe-pump that delivered a continuous flow of distilled water at flow rates of 2, 5, 10, and 25 µL/min. The pressures and resistances of tubes were measured at a steady flow rate with full-length, half-length, and absence of intraluminal stents. RESULTS: The mean outflow resistance of the two types of tubes ranged from 3.0 ± 1.9 to 3.8 ± 1.7 mmHg/µL/min with a full-length intraluminal stent, 1.8 ± 1.1 to 2.2 ± 1.1 mmHg/µL/min with a half-length intraluminal stent, and 0.1 ± 0.0 to 0.2 ± 0.0 mmHg/µL/min without an intraluminal stent. Theoretically, for a physiologic state with a flow rate of 2 µL/min and episcleral venous pressure of 6 mmHg, the mean pressures of tubes were expected to be 13.2 ± 3.0, 10.5 ± 2.4, and 6.4 ± 0.2 mmHg in MicroMT with full-length, half-length, and absence of intraluminal stents, respectively, and 12.5 ± 3.9, 9.6 ± 2.4, and 6.2 ± 0.2 mmHg in Finetube MT with full-length, half-length, and absence of intraluminal stents, respectively. The pressure variance also decreased with intraluminal stent retraction (p < 0.01). CONCLUSIONS: The small diameter tubes of 100 and 200 µm internal diameters, with 7-0 and 5-0 nylon intraluminal stents, respectively, used in the MT-type glaucoma shunt device showed safe and effective outflow characteristics.

Implantation of a Modified Baerveldt Glaucoma Implant with a Smaller Tube and Intraluminal Stent

No abstract available.

Performance of and Pressure Elevation Formed by Small-diameter Microtubes Used in Constant-flow Sets

PURPOSE: We explored the performance of and pressure elevation caused by small-diameter microtubes used to reduce overfiltration. METHODS: Using a syringe pump-driven constant-flow setting (2 µL/min), pressures were measured for polytetrafluoroethylene (PTFE) microtubes 5 mm in length with inner diameters of 51, 64, and 76 µm and for polyether block amide (PEBAX) microtubes with an inner diameter of 76 µm. Experiments (using microtubes only) were initially performed in air, water, and enucleated pig eyes and were repeated under the same conditions using intraluminal 9/0 nylon stents. RESULTS: The pressures measured in air in 51-, 64-, and 76-µm-diameter PTFE microtubes differed significantly (22.1, 16.9, and 12.2 mmHg, respectively; p < 0.001), and that of the 76-µm-diameter PEBAX microtube was 15.8 mmHg (p < 0.001 compared to the 12.2 mmHg of the 76-µm-diameter PTFE microtube). The pressures measured in water also differed significantly among the three microtubes at 3.9, 3.0, and 1.4 mmHg, respectively, while that in the PEBAX microtube was 2.6 mmHg (all p < 0.001). Using the intraluminal stent, the pressure in water of the three different PTFE microtubes increased to 22.6, 18.0, and 4.1 mmHg, respectively, and that in the PEBAX microtube increased to 10.5 mmHg (all p < 0.001). Similar trends were evident when measurements were performed in pig eyes. CONCLUSIONS: Although microtubes of smaller diameter experienced higher pressure in air, reduction of the inner diameter to 51 µm did not adequately increase the pressure attained in water or pig eyes. Insertion of an intraluminal stent effectively elevated the latter pressures. PEBAX microtubes created higher pressures than did PTFE microtubes.

Influence of Phacoemulsification on the Progression of Diabetic Retinopathy

PURPOSE: To evaluate influence of phacoemulsification on the progression of diabetic retinopathy METHODS: The medical charts of 82 eyes of 41 patients with nonproliferative diabetic retinopathy (DR) who had unilateral phacoemulsification were retrospectively reviewed. The course of diabetic retinopathy was followed up for more than 2 years. Each stage of DR progression was indicated by a unique score, and a comparison of the progression of DR between operated and non-operated eyes was performed using the devised scoring system. RESULTS: The progression of 82 eyes at a mean follow-up period of 28 months was evaluated. DR progressed more in operated eyes than in non-operated eyes (P=0.006). The progression of proliferative DR in operated eyes (19.5%, 8 eyes) was significantly greater (P=0.029) than in non-operated eyes (2.4%, 2 eyes). CONCLUSIONS: Phacoemulsification resulted in a progression of diabetic retinopathy. Careful approach to the cataract patients with diabetic retinopathy would be recommended.

A Qualitative Evaluation of Problem-Based Learning Curriculum by Students' Perceptions / 한국의학교육

PURPOSE: Recently established in 1997, Sungkyunkwan University School of Medicine was the first medical school in Korea to adopt problem-based learning (PBL) as a core curriculum from the very beginning. The purpose of this study was to evaluate the PBL curriculum from the viewpoint of the medical students. METHODS: This study used a qualitative approach to understand students' perceptions of the positive aspects of PBL. A total of 22 second-year medical students at Sungkynkwan medical school were surveyed. Student perceptions were obtained from questionnaires and face-to-face interviews. The interview was designed to evoke more personal and in-depth responses. RESULTS: Students' perceptions of the effects of PBL were found to be very favorable. Most students showed positive responses on the issues of more active learning attitude, self-directed learning, motivation to study, improved problem solving, and integrated learning. CONCLUSION: The results of this study demonstrated that the students had a good understanding of PBL and experienced its positive aspects of PBL approach. It might be concluded that PBL was successfully implemented into the curriculum and specific and expected effects of PBL accomplished.

The Results of Posterior Subtenon Steroid Injection in Uveitis Patients

PURPOSE: Locally administered corticosteroids have been widely used in the treatment of inflammatory eye disease. The main purpose of this study is to analyze the treatment effects and the complications of posterior subtenon steroid injection in uveitis patients. METHODS: Retrospective study was performed on 36 eyes of 32 patients diagnosed as uveitis and treated with subtenon steroid injection. RESULTS: Sixty eight consecutive injections of triamcinolone were performed, and the mean follow-up duration was 6.9 months (1~28 months). Visual acuity was improved in 28 (88%) of 32 patients, and mean time to improvement was three weeks after the injection. Intraocular pressure was increased (>21 mmHg) in 10 eyes (31%) of 10 patients, with mean onset of three weeks after the initial injection. The increased pressures was not controlled by medical treatment and additional filtration surgery was needed in 2 eyes (6%). Cataracts were newly developed or worsen in 5 eyes (15.6%) of 4 patients and 2 eyes underwent cataract surgery. CONCLUSIONS: Although a postrerior subtenon steroid injection effectively improved visual acuity in most uveitis patients, side effects, such as the increased intraocular pressure or cataract were developed. The complication rate as well as treatment effect should be taken into consideration when using this treatment method.

Intraocular Pressure Change after Glaucoma Implant Surgery with Releasable suture

PURPOSE: To find the factor that affects the long-term intraocular pressure after glaucoma implant surgery with releasable suture. METHODS: We retrospectively reviewed the medical records of the 33 patients (36 eyes) who had undergone glaucoma implant surgery with our own expanded-Polytetrafluoroethylene (e-PTFE) membrane-tube implant with temporary closure of the tube by releasable suture. Data such as timing of suture release, IOP's before and after surgery and the amount of pressure change during follow-up were collected, and we tried to find the factor that influenced the IOP at the last visit. RESULTS: The preoperative IOP was 43.2+/-14.6 mmHg and the suture was released at day 17.9+/-9.5 after surgery. The IOP just before the release of suture was 33.5+/-17.1 mmHg. The pressure was dropped to 15.1+/-13.7 mmHg, measured at 30 minutes after the release of the suture. The IOP was stabilized to 14.9 +/-9.5 mmHg at 12.2+/-7.0 days after the release. The average follow-up was 32.8+/-26.3 months and the IOP at the last visit was 17.3+/-10.5 mmHg. Four eyes (11%) had hypotony (IOP less than 8 mmHg) before release of the suture, thirteen eyes (41%) showed hypotony 30minutes after release, and three eyes(8%) showed hypotony at the last visit. Multiple linear regression analysis revealed that the IOP at 30 minutes after release of the suture had a positive correlation with the IOP at the last visit (r=0.642,p=0.000). CONCLUSIONS: In the membrane-tube implant surgery for the refractory glaucoma, the releasable suture echnique is helpful to prevent the early postoperative hypotony. By measuring early post-release IOP after implant surgery with releasable suture technique, we might predict the behavior of long term IOP change; the lower post-release IOP, the better long-term pressure control.

Clinical Results of Penetrating Keratoplasty after Glaucoma Surgery

PURPOSE: We retrospectively reviewed the medical records of the patients who had undergone penetrating keratoplasty after glaucoma surgery, to evaluate the surgical outcome of penenetrating keratoplasty associated with glaucoma surgery. METHODS: Twelve patients, 12 eyes were reviewed. Graft status and postoperative intraocular pressure were main outcome measures. And success was defined as thin, clear corneal graft and IOP control between 6 and 21 mmHg after at least 6 month follow-up. RESULTS: The mean age of the patients was 40 year old and male to female ratio was 9 to 3. Mean postoperative follow up time was 12 months for Penetrating keratoplasty and the mean period between glaucoma surgery and penetrating keratoplasty was 12 months. Seventy five percent(9 eyes) maintained clear corneal graft and 67%(8 eyes) showed successful IOP control and both clear graft and IOP control in 58%(7 eyes). CONCLUSIONS: Fifty-eight percent(58%) of our cases showed successful outcome. With the knowledge of better timing for a surgical intervention and an improvement of surgical techniques, there will be an increased success rate.

A Case of Herpes Zoster Sine Herpete following Pediatric Penetrating Keratoplasty

Herpes zoster ophthalmicus sine herpete(HZSH), which means herpes zoster ophthalmicus(HZO)without skin eruption, is one of the atypical manifestations of varicella-oster virus(VZV)infection. Idiopathic iridocyclitis or acute retinal necrosis without skin lesion secondary to varicella-oster virus are good examples. Diagnosing zoster iridocyclitis without skin eruption is difficult because in the absence of typical skin eruption it is difficult to suspect varicella-zoster virus as the cause of inflammation in the absence of typical skin eruption. We describe here a rare case of a pediatric patient with severe iridocyclitis in a pediatric patient after penetration of keratoplasty in whom VZV DNA was detected using the DNA amplification and polymerase chain reaction(PCR)method. To our best knowledge, this is the first case report of varicella-zoster virus iridocyclitis in a pediatric patient after penetrating keratoplasty.

The Use of Standardized Patients in Medical Education / 한국의학교육

Standardized patients(SPs) are either persons who are trained to simulate a patient's illness in a standardized way or actual patients. Newly established Sungkyunkwan University School of Medicine started problem based learning(PBL) curriculum and SP program has been developed for teaching and evaluating clinical skills in medical education. Standardized patients were recruited from the community. Small-group SP training sessions were operated by two SP trainers and supervised by a clinical faculty. Standardized patients were used in teaching and practicing interviewing and physical examination skills for students. We report the experiences of initial stage of SP program and views of students and SPs. We surveyed 35 first-year medical students after SP encounters. The questionnaire was about effectiveness and realism of SP and general views of students. Another simple survey was conducted on 12 SPs who had participated in SP program for more than 4 months. Most students answered that SP encounters were interesting and more helpful in learning history-taking and clinical skills. The attitude of SPs was enthusiastic and their simulations were rated as appropriate and acceptable. The evaluations of the SP program by students, SPs, and faculty were very favorable. As an alternative to real patients, the SP can offer advantages such as availability, adaptability and controllability. If trained well, they also can provide objective feedback to the students. The SP offers a readily available tool for teaching and evaluating the clinical performance and interpersonal skills of medical students. It is suggested that the use of SP is stimulating and challenging way of teaching and evaluating in medical education.

Intermediate-term Result of e-PTFE Membrane Implant Surgery for Refractory Glaucomas

Recently, various tube-shunt implants have been used in treating refractory glaucomas.They have large volumed reservoir portion made of hard materials.We made a new implant with soft and freely malleable membrane[expanded polytetrafluoroethylene, e-PTFE]as a reservoir portion attached to the conventional silicone tube. Based on the encouraging result from experimental animal study, we performed a clinical trial for the membrane-tube implant.We performed Glaucoma Tube-Shunt Implant surgery using double layers of e-PTFE membrane and silicone tube with its one end fixed between the two layers.The subjects had refractory glaucomas without useful vision who visited our hospital from May 1991 to Sep.1995. There were 40 eyes of 37 patients and their mean follow-up period was 32.6 months.We could control the IOP within 6~21 mms of mercury in 26 eyes[65.0%, Success].In remaining 14 eyes, we could not control the IOP or additional surgery was needed to control the IOP or treat severe complications[35.0%, Failure].The Kaplan-Meier Survival for IOP control was 78.4% at 1 yr, 71.6%at 2 yr, and 60.3%at 3 yr.The complications were similar to those of other commercially available Glaucoma implants. This new implant is made of soft, freely malleable membrane for the reservoir portion with small volume which can be inserted with smaller incision on the conjunctiva with less complication.We have obtained comparable result from this membrane-tube implant to other implants, and it may be considered as an another substitute for the treatment of refractory glaucomas.

A Six-Week, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Evaluate Hypotensive Efficacy and Safety of 2%Dorzolamide vs Placebo Ophthalmic Solution

Two percent dorzolamide, a topical carbonic anhydrase inhibitor (CAI), was developed to reduce the side effects associated with systemic CAI such as fatigue, anorexia, dysesthesia, etc. and to effectively reduce the elevat-ed intraocular pressure(IOP). This study was designed to evaluate the effectiveness and safety of 2%dorzolamide in Korean patients with primary open-angle glaucoma or ocular hypertension. In this randomized, double-blind, placebo-controlled clinical study, 2%dorzolamide or placebo was given three times a day to the patients with primary open-angle glaucoma or ocular hypertension (22mmHg < or =IOP < or =30mmHg)to evaluate the hypotensive effect and safety of dorzolamide during the period of 6 weeks. After 1,3, and 6 weeks treatment, the mean percent decrease of IOP from baseline in the dorzolamide group (16.3 +/-8.9%,17.9 +/- 9.8%,and 18.2 +/-8 .7 %, respectively) was significantly larger (p<0.01)than that in the placebo group (7.5 +/- 6.8%, 8.5 +/-9.5%, 10.4 +/-10.4%, respectively). The decrease of IOP was also significant in each group(p<0.01)compared to the pre-treatment IOP. During the period of treatment, burning sensation was more frequent in the dorzolamide group (p<0.05). In conclusion,this study has shown that the topical application of 2% dorzolamide effectively reduces IOP without serious adverse effects in Korean patients with primary open-angle glaucoma or ocular hypertension.

The Relationship Between the Activity of Matrix Metalloproteinase in the Aqueous Humor and the Development of Primary Open Angle Glaucoma

To investigate whether the abnormal expression of matrix metalloproteinases(MMPs) in the aqueous humor may case the development of glaucoma, the activity of MMP in the aqueous humor of galucoma and cataract patients were measured and compared. Six primary open angle glaucoma(POAG), 2 chronic angle closureglaucoma(CACG), 2 normal tension glaucoma(NTG), and 14 cataract patients were enrolled. Aqueous humor of each patients were collected during surgery, and total protein concentration and activity of gelatinase A in the aqueous humor were measured by protein assay kit and zymography, respectively. Total protein concentration and gelatinase A activity of POAG patients were increased by 2.1 times and 3.9 times, respectively compared to those of cataract patients. However, there were no statistically significant changes in total protein concentration and gelatinase A activity of CACG and NTG patients compared to those of cataract patients. In conclusion, the development of POAG may be associated with the abnormal expression of MMP in the aqueous humor.

Treatment for Persistent Hypotony due to Cyclodialysis

We assessed 14 eyes of 14 patients with persisting hypotony due to cyclodialysis by blunt trauma of after secondary intraocular lens implantation. All the 14 eyes showed persistent hypotony and no increment of intraocular pressure(IOP) nor the visual acuity during the follow up period of average 4.6 months before treatment, We treated these eyes with argon laser photocoagulation and/or direct cyclopexy. After treatment, the IOP changed from 3.7+/-1.5mmHg to 13.7+/-5.1mmHg, and posttreatment IOP was greater than 8mmHg in 12 eyes. All 14 eyes showed visual acuity under 0.3 before the treatment and after treatment, the visual acuity improved by 4.2+/-3.3 lines at the last follow up visit. The follow up period was 12.5 months on average. Before treatment, all the 12 eyes that had no medial opacity showed hypotony maculopathy, but after treatment only 4 eyes showed persisting hypotony maculopathy. A-scan axial length measurement was performed on 8 eyes before and after treatment, and the axial lengths were increased by 0.90+/-0.88mm after treatment in 7 eyes in which IOP were increased. The change in refractive errors before and after treatment was possible to be assessed in 9 eyes and among them, 7 eyes showed increment of IOP. Among those 7 eyes, 2 eyes had shallow chambers with anteriorly displaced lens before treatment and showed repositioning of lenses and hyperopic shift by +2.86 Dsph on average after treatment, but the remaining 4 eyes excluding one eye that received lensectomy at the time of surgery for taumatic cataract, showed myopic shift by -2.31 Dsph on average after treatment.

The Normal Values of Optic Disc Parameters According to the Optic Disc Size

We analysed the optic nerve head of 151 normal eyes with 8 confocal scanning laser ophthalmoscope (TopSSTM, Laser Diagnostic Technologies, Inc.), and obtained the normal values of each parameters. As the optic disc size increases, the cup shape, effective area, 1/2 depth area, C/D ratio, neuroretinal rim area, volume above, volume below, and 1/2 depth volume also increase. Therefore we obtained the normal values of these parameters according to the optic disc size. The entire subjects were divided into four groups according to the disc area, each group of 1. 5mm2-2.0mm2, 2.0mm2-2.5mm2, 2.5mm2-3.0mm2, and 3.0mm2-3.5mm2`, respectively. The normal values of other parameters such as contour variation, rnean contour depth, average depth, maximum depth, average slope, and maximum slope which are not affected by optic disc size were obtained without grouping. This may minimize the error in evaluating the optic disc parameters and may be useful in the early detection of glaucomatous optic disc changes.

Pseudophakic/Aphakic Retinal Detachment Surgery Using Scleral Depression Technique

In aphakic/pseudophakic retinal detachments, difficulty in visualizing the peripheral retina and perhaps higher incidence of proliferative vitreoretinopathy result in lower success rate than phakic retinal detachment. We performed pars plana vitrectomy on 20 eyes with aphakic/pseudophakic retinal detachment. In most cases, we combined scleral bucking or encircling procedure. Using scleral depression technique, we found retinal breaks, dissected the vitreous base meticulously, and removed the vitreoretinal tractions. Intraoperatively, we were able to find retinal breaks in 12 eyes in which retinal breaks were not identified preoperatively, and identify additional retinal breaks in 3 of the remaining 8 eyes. We obtained anatomical success in all eyes and favorable visual acuity of better than 0.025 in 16 eyes (80%). These results suggest that finding all retinal breaks and removing vitreoretinal tractions are directly related to the improvernent of the surgical results.

Short-term Results of Laser Photocoagulation for Juxtafoveal/Extrafoveal Choroidal Neovascularization

To evaulate the closure and recurrence rate of laser treatment for juxtafoveal and extrafoveal CNV with well-defined boundary, we studied 15 eyes of 15 patients that could be followed up for at least 1 year. The follow-up ranged form 12 to 31 months(mean, 17.1 months). Three and six weeks after laser treatment, all neovascularization was obliterated. Eight months, after laserphotocoagulation was obliterated. Eight months, after laser photocoagulation there was one recurrence in juxtafoveal CNV. In7 of 10 laser-treated eyes in classic, extrafoveal CNV, visual or more in three eyes. Of 5 laser-treated eyes in classic, juxtafoveal CNV, visual acuity had changed by no more than 2 lines in 3 eyes and decreased by 2 or more lines in 2 eyes. The short-term results of laser treatment for classic CNV were good, but long-term evaluation is required.

Use of Medical Terms and Residency Program in Korea / 한국의학교육

No abstract available.