Short-Term Results of Dexamethasone Intravitreal Implant in Patients with Refractory Diabetic Macular Edema

PURPOSE: To evaluate the effectiveness of a dexamethasone intravitreal implant (Ozurdex(R)) in the treatment of diabetic macular edema refractory to combined treatment of bevacizumab and triamcinolone. METHODS: We reviewed 9 eyes of 9 patients with diabetic macular edema treated with dexamethasone intravitreal implant. The patients were included in the study if presenting with refractory diabetic macular edema of more than 3 months despite combined treatment of intravitreal bevacizumab injection with posterior subtenon triamcinolone injection or intravitreal triamcinolone injection. We assessed the best-corrected visual acuity (BCVA) and central macular thickness (CMT) using optical coherence tomography at initial visit and 1, 3 and 4 months. RESULTS: The mean follow-up was 6.7 +/- 2.2 months. The baseline mean BCVA was 0.81 +/- 0.47 logarithm of the minimum angle of resolution (log MAR), which improved to 0.61 +/- 0.37 log MAR (p = 0.017), 0.57 +/- 0.38 log MAR (p = 0.011) and 0.62 +/- 0.36 log MAR (p = 0.027) at 1 month, 3 months and 4 months, respectively. The baseline mean CMT was 558.0 +/- 110.32 microm and decreased to 325 +/- 64.21 microm (p = 0.008) and 300.22 +/- 59.46 microm (p = 0.008) at 1 month and 3 months, respectively, then increased to 468.44 +/- 150.85 microm (p = 0.058) at 4 months after injection. CONCLUSIONS: Dexamethasone intravitreal implant showed short-term efficacy in the treatment of diabetic macular edema refractory to combined treatment of bevacizumab and triamcinolone and produced significant improvements in BCVA and CMT until 3 months after injection. The CMT then increased, but BCVA was sustained until the fourth month.

Bilateral Nongranulomatous Uveitis with Infective Endocarditis

A 32-year-old male who had infective endocarditis complained of photophobia and blurred vision in both eyes. Biomicroscopic examination and fundus examination revealed anterior chamber reaction, vitritis, optic disc swelling, and Roth spots. He was diagnosed with bilateral nongranulomatous uveitis and treated with topical steroid eye drops and posterior sub-Tenon injection of triamcinolone. His visual symptoms were resolved within 1 week, and inflammation resolved within 4 weeks after treatment.

Surgical Removal of Sub-Tenon Triamcinolone Acetonide in Cases of Increased Intraocular Pressure after Sub-Tenon Injection

PURPOSE: To report cases of the surgical removal of sub-Tenon triamcinolone acetonide to control increased intraocular pressure after sub-Tenon triamcinolone acetonide injection. CASE SUMMARY: Three patients had no response to maximal medical treatment to control suddenly increased intraocular pressure after sub-Tenon triamcinolone acetonide (40 mg) injection to treat diabetic macular edema. The anterior chamber angle was open in all patients, and there was no neovascularization in the iris or anterior chamber angle. Slit lamp biomicroscopy showed deposition of triamcinolone acetonide in the inferior sub-Tenon area. Intraocular pressure was decreased within the normal range without any medication after removal of triamcinolone acetonide precipitates. CONCLUSIONS: Surgical removal of sub-Tenon triamcinolone acetonide can be as a primary treatment option in cases of increased intraocular pressure which shows no response to maximal medical treatment after sub-Tenon triamcinolone acetonide injection.

Spectral Domain Optical Coherence Tomography Findings of Butterfly Shaped Pigment Dystrophy

PURPOSE: The butterfly-shaped pigment dystrophy is an extremely rare autosomal dominant retinal disorder. The authors present a case of butterfly-shaped pigment dsytrophy not reported previously in Korea. CASE SUMMARY: A 45-year-old man had bilateral blurred vision for 2 years. His visual acuity was 0.2 in the right eye, and 0.3 in the left and was uncorrected. Funduscopically, yellow pigment deposits were present at the level of retinal pigment epithelium (RPE) in the central macula of both eyes. Fluorescein angiography (FA) revealed a central, dark, butterfly-shaped lesion surrounded by a region of hyperfluorescence, Spectral domain optical coherence tomography (OCT) showed thick elevation of the RPE with hyperreflectivity and disruption of the inner and outer segment (IS/OS) interface of the photoreceptors. The patient had normal color vision, visual field and electroretinograms and reduced electrooculograms. CONCLUSIONS: In general, butterfly-shaped pigment dystrophy is known to have good visual prognosis. However, in some cases the disease can be a chronic progressive disorder with secondary involvement of the photoreceptors, as exemplified this patient. The authors anticipate more detail regarding the natural course of this disease will be obtained through spectral domain OCT.

A Case of Intravitreal Bevacizumab Injection for the Treatment of Choroidal Neovascularization in Angioid Streaks

A 56-year-old Korean woman presented with decreased visual acuity of the right eye. She had a history of two photodynamic therapy treatments for choroidal neovascularization (CNV) due to angioid streaks in her left eye with central scarring and low visual acuity. She was diagnosed with subfoveal CNV due to angioid streaks in her right eye and treated with six intravitreal bevacizumab (1.25 mg / 0.05 mL) injections over one year. Best corrected visual acuity improved from 20 / 125 at baseline to 20 / 50 at the final visit. The area of CNV had changed into a fibrotic scar by the final visit, and fluorescein angiography and indocyanine green angiography revealed no evidence of leakage. Optical coherence tomography showed that central macular thickness decreased from 311 microm at baseline to 203 microm with complete resolution of subretinal and intraretinal fluid at the final visit. Intravitreal bevacizumab for CNV associated with angioid streaks prevented the progression of disease and resulted in the improvement of visual acuity after one year of follow-up in our patient.

Posterior Sub-Tenon Triamcinolone Acetonide Injection for Recurrent Diabetic Macular Edema after Repeated Intravitreal Bevacizumab Injections

PURPOSE: To evaluate posterior sub-Tenon injection of triamcinolone acetonide (TA) for recurrent diabetic macular edema (DME) after repeated intravitreal bevacizumab (IVB). METHODS: This is a retrospective interventional case series comprised of 35 eyes (32 patients) with recurrent clinically significant DME after two or more IVB treatments. All patients were administered TA 40 mg injections. Best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP) were reevaluated at months 1, 3, and 6. RESULTS: The baseline OCT showed five eyes with diffuse retinal thickening, 18 eyes with cystoid macular edema, and 12 eyes with serous retinal detachment. Mean BCVA improved at months 1 and 3, and mean CMT decreased at months 1 and 3. However, mean BCVA and CMT at six months was not different from baseline. Each DME pattern showed significant improvements in BCVA and CMT at three months. Mean IOP at months 1, 3, and 6 did not show any significant difference from baseline. No eyes showed complications including cataract progression or endophthalmitis. CONCLUSIONS: Posterior sub-Tenon injection of TA should be considered for patients with recurrent DME after repeated IVB. The studied eyes showed improvements in BCVA and CMT during three months in all of the three patterns of DME.

Visual Prognosis and Foveal Reattachment After Reattachment Surgery in Macula-off Retinal Detachment

PURPOSE: To evaluate the visual prognosis and time course of the foveal reattachment according to operation methods and preoperative factors using optical coherence tomography (OCT) after successful reattachment surgery in cases of macula-off rhegmatogenous retinal detachment. METHODS: From Jan 2006 to Aug 2008, 47 patients who underwent retinal reattachment surgery for macula-off retinal detachment who were followed up for more than 12 months were enrolled in this study. Thirty patients underwent vitrectomy, and 17 patients underwent a scleral buckle procedure. Ophthalmological examinations, including best-corrected visual acuity, slit-lamp examination, fundus examination, and OCT, were performed before surgery and at 1, 1.5, 3, 6, and 12 months after surgery. RESULTS: The foveal reattachment time was shorter after vitrectomy than after the buckle procedure (p<0.05). Postoperative visual acuity was better when the height of the detached fovea, as viewed by OCT, was shorter, although foveal reattachment time was not related to visual prognosis. CONCLUSIONS: OCT may help to predict visual outcome and to assess macular changes in patients with macula-off retinal detachment after successful reattachment surgery.

The Results of Nation-Wide Registry of Age-related Macular Degeneration in Korea

PURPOSE: To evaluate the incidence and clinical features of age-related macular degeneration (AMD) in Korea. METHODS: Web-based (www.armd-nova.or.kr) registration was conducted for AMD patients aged 50 or more who were newly diagnosed by retinal specialists in Korea from August 20, 2005 to August 20, 2006. Patient data including ophthalmologic examination, fundus photography, fluorescein angiogram and/or indocyanin green angiogram (ICG), past medical history, behavioral habit, combined systemic diseases were up-loaded. RESULTS: Among finally enrolled 1,141 newly diagnosed AMD patients, 690 patients (60.5%) were male and 451 patients (39.5%) were female. The average age of AMD patients was 69.7+/-8.0. Early AMD was observed in 190 patients and 951 patients had late AMD. Classic choroidal neovascular membrane (CNVM) was observed in 18.6% of exudative AMD patients and 63.4 % had occult CNVM. Subfoveal CNVM was observed in 80.4% of the patients with CNVM. Among the 580 exudative AMD eyes that performed indocyanin green angiography (ICG), 184 eyes (31.7%) had polypoidal choroidal vasculopathy (PCV) and 36 eyes (6.2%) showed retinal angiomatous proliferation (RAP). Age, male gender, smoking, diabetes and hypertension significantly increased the risk of the AMD among Koreans. CONCLUSIONS: Because of the low rate of participation by retinal specialists, definite incidence of AMD was not obtainable. However, the estimated 1-year AMD incidence in the Pusan area of Korea is at least 0.4%. In contrast to Western people, 31.7% of exudative AMD cases were revealed to be PCV and 6.2% were revealed to be RAP. This discrepancy between ethnic groups should be considered in the diagnosis and treatment modality selection of Korean AMD patients.

Rifabutin Related Uveitis in AIDS: A Case Report

PURPOSE: To describe a case of symptomatic rifabutin-related uveitis with hypopyon and vitreous opacity in apatient with acquired immunodeficiency syndrome infected with Mycobacterium tuberculosis. CASE SUMMARY: A 33-year-old male patient with acquired immunodeficiency syndrome was referred to our clinic for abruptly decreased vision in his right eye. Multi-drug therapy with rifabutin was administered for 5 weeks to treat tuberculosis enteritis and pulmonary tuberculosis. Visual acuity of the right eye was hand motion and hypopyon as well as vitreous opacity was found in ocular examinations. Other serologic tests, anterior chamber paracentesis and lumbar puncture test were normal. Rifabutin was immediately stopped and topical steroid and cycloplegics were administered, which resulted in resolution of the hypopyon, vitreous opacity and visual acuity. Four weeks after the initial episode, rifabutin was restarted to treat the pulmonary tuberculosis and rifabutin-related uveitis relapsed in the opposite eye. CONCLUSIONS: Rifabutin-related uveitis should be considered in cases of uveitis in immunosuppressive patients, especially in acquired immunodeficiency syndrome patients. Underlying disease and medication history should be carefully assessed.

A Case of DiGeorge Syndrome With Ocular Manifestation

PURPOSE: DiGeorge syndrome (chromosome 22q11.2 deletion syndrome) is a syndrome of multiple congenital anomalies characterized by hypoplasia or aplasia of the thymus and parathyroid, cardiovascular malformation, immune deficiency, cleft palate, characteristic facial features, and hypocalcemia. Ocular findings of DiGeorge syndrome are posterior embryotoxon, retinal vascular tortuosity, strabismus, ptosis, amblyopia and tilted optic disc. The authors present a case of DiGeorge syndrome with ocular manifestation not reported previously in Korea. Case summary: A six-year old female diagnosed with DiGeorge syndrome was referred to the authors' department within the hospital. The chief complaint was blurring vision in both eyes. Best corrected visual acuity of the right eye was 0.5 and of the left eye was 0.63. Cycloplegic refraction revealed high hyperopia and astigmatism in both eyes (OD: +7.25 Dsph; -2.5 Dcyl axis 180degrees, OS: +6.25 Dsph; -3.75 Dcyl axis 180degrees). In addition, hypertelorism, ptosis and tortuous retinal vessels during fundus examination were noted. CONCLUSIONS: Upon the initial diagnosis of DiGeorge syndrome in children, a comprehensive ocular examination is necessary because other ocular conditions may exist which can affect the visual development of the patient.

The Efficacy of Photodynamic Therapy With Verteporfin for Polypoidal Choroidal Vasculopathy: Retrospective Multi-Center Case Study

PURPOSE: To evaluate the efficacy of photodynamic therapy (PDT) with verteporfin for polypoidal choroidal vasculopathy (PCV) in Korean patients. METHODS: Clinical data of patients who were treated with PDT for PCV and followed up for more than 6 months were collected from 14 hospitals around the country. The changes in the best corrected visual acuity, angiographic outcome, retinal thickness measured by optical coherence tomography (OCT), and adverse effects of treatment were evaluated. RESULTS: Eighty six patients (86 eyes) were recruited (male: 75.6%, age: 65.9+/-8.3 years, mean follow-up: 14.8+/-10.2 months). The mean logMAR visual acuity at baseline was 0.55+/-0.32 and did not show any statistically significant difference from the final mean logMAR visual acuity (0.53+/-0.54) (p=0.639). The mean treatment session number of PDT was 2+/-1.2. Visual acuity stabilized or improved in 70.9% of patients. Visual acuity improved by more than 2 lines in 33 eyes (38.4%) and worsened by more than 2 lines in 21 eyes (24.4%) of patients. Vascular leakage decreased in 62.5% of patients in fluorescein angiography and polypoidal lesions disappeared or were reduced in 57.3% of patients in indocyanine green angiography. There was no systemic adverse effect of PDT, but increased subretinal hemorrhage after PDT occurred in 10 eyes (11.6%). CONCLUSIONS: In polypoidal choroidal vasculopathy, photodynamic therapy with verteporfin is safe and effective for preserving visual acuity and reducing vascular leakage and retinal thickness.

Clinical Evaluation of Patients with Nonproliferative Diabetic Retinopathy Following Medication of Anthocyanoside: Multicenter Study

PURPOSE: To prospectively investigate the change of clinical manifestations after 1 year of administration of anthocyanoside (Tagen-F(R)) to patients with NPDR-associated macular edema. METHODS: One hundred seventy-five eyes in 88 patients were enrolled in this study, at 5 centers, from March, 2005 to October, 2005. Patients took 3 capsules of Vaccinium myrtillus extract (170 mg/capsule, Tagen-F(R), Kukje pharmaceutical) per day. The primary endpoints were corrected visual acuity and contrast sensitivity which were checked at 2 months following the beginning of treatment [East 1]. The secondary endpoints were the number of hard exudates, microaneurysms, leaking points and the changes of foveal thickness. These were examined at the beginning of, 6 months after, and 12 months after treatment. RESULTS: Corrected visual acuity showed no significant changes during 12 months. Contrast sensitivity improved gradually, especially in 12, 16 cycles per degree [East 2]. There was no statistically significant changes in the numbers of hard exudates, microaneurysms, and leaking points. Foveal thickness measured by OCT was maintained and there was no aggravation of macular edema. CONCLUSIONS: There was marked improvement of contrast sensitivity in patients with NPDR after 1 year of administration of anthocyanoside (Tagen-F(R)), and it might contribute to the quality of vision and the satisfaction of patients. Visual acuity and macular edema were maintained without aggravation.

N-Methyl-D-Aspartate (NMDA)-induced Apoptosis in Rabbit Retina

PURPOSE: To evaluate the involvement of apoptosis in N-methyl-D-aspartate (NMDA)-induced excitotoxicity in the rabbit retina. METHODS: After intravitreal injection of 680 and 2,000 nmoles of NMDA in rabbit eyes, the eyes were enucleated at 2, 16, and 60 hours and 1 and 2 weeks. The apoptotic cell death was determined with TdT-mediated biotin-dUTP nick end labeling (TUNEL) stain, and immunohistochemical stains of Bcl-2, Bax, and caspase-3 were performed. RESULTS: TUNEL showed increased labeling scattered in the ganglion cell layer and inner nuclear layer from 16 to 60 hours. The number of TUNEL-positive nuclei decreased at 60 hours, and none was observed at 2 hours, 1 week, and 2 weeks. More TUNEL-positive nuclei were seen with injection of 2,000 nmoles compared to 680 nmoles. Bcl-2, Bax, and caspase-3 were seen histologically as early as 2 hours in the ganglion cell layer and inner nuclear layer; there was no stained nuclei with the TUNEL stain. At 2 hours after intravitreal NMDA injection, Bcl-2, Bax, and caspase-3 were also stained in Muller cells. CONCLUSIONS: This study showed that apoptosis is involved in NMDA-induced excitotoxicity in the rabbit retina. Bcl-2, Bax, and caspase-3 may play important roles in modulating the apoptosis in NMDA-induced excitotoxicity, and Muller cells are involved in the apoptotic pathway.

Intravitreal Versus Subtenon Injections of Triamcinolone Acetonide for Diabetic Macular Edema

PURPOSE: To retrospectively evaluate the clinical effect of intravitreal (IVT) and posterior subtenon (PSTT) triamcinolone acetonide (TA) injection in diabetic macular edema. METHODS: Fifty eyes of 43 patients with diabetic macular edema (DME) were included. Twenty-two eyes in the IVT group received 4 mg/0.1 ml intravitreal TA injections and 26 eyes in the PSTT group received 40 mg/1.0 ml subtenon TA injections. LogMAR visual acuity and intraocular pressure (IOP) were measured and, using OCT, central macular thickness (CMT) and total macular volume (TMV) were also measured before and 1, 3, and 6 months postoperatively. RESULTS: Both groups showed significant decreases in the mean CMT and TMV. The mean CMT in the IVT group was significantly thinner than that of the PSTT group 1 month postoperatively. The percentage reduction in CMT and TMV were also greater in the IVT group than the PSTT group 1 month postoperatively. Both groups showed significant improvements in mean visual acuity, with no significant difference between the two groups. However, at 1-month postoperative improvement in visual acuity was significantly greater in the IVT group than the PSTT group. The mean IOP in the IVT group was also greater than that in the PSTT 1 month postoperatively. CONCLUSIONS: Both injections caused a significant increase in visual acuity and a decrease in CMT and TMV. The effect was more pronounced in the IVT group. However, the PSTT injection also appeared to be a safe and effective technique for the treatment of DME.

Effects of Zinc and Hypothermic Process during the Light and Dark Adaptation of Vertebrate Retina

PURPOSE: The purpose of this study was to clarify the effects of zinc treatment and hypothermia on visual adaptation and visual sensitivity in bullfrogs (Rana catesbeiana), which are poikilothermal animals capable of adjusting quickly to environmental temperature changes. METHODS: The effects of both zinc treatment and hypothermia on visual sensitivity were studied by using electroretinogram (ERG) recording and absorption spectra scanning before and after zinc and TSQ (N-[6-methoxy-8-quinolyl]-p-toluene sulfonamide) treatment, with or without temperature changes. RESULTS: In spite of malnutrition due to hibernation, the optimal zinc concentration effect was obtained at 10-4 M (10-2 M 200 microliter ZnCl2 in 20 microliter Ringer's solution) according to ERG recording. After zinc treatment and hypothermia induction, increments of all ERG components and thresholds were taken by ERG recording. These results showed that both zinc treatment and hypothermia may increase visual sensitivity during visual adaptation. In spectral scans, the absorbance increment due to zinc treatment and hypothermia was shown over the whole spectral range (400~750 nm), and it was especially prominent at alpha-peak (about 500 nm). In addition, there was a decrease in absorption differences between dark adaptation and light adaptation after zinc treatment. Furthermore, according to the visual sensitivity decrement using TSQ as a zinc specific chelator, this visual sensitivity increase was shown to be caused by zinc. CONCLUSIONS: As the results suggest, both zinc treatment and hypothermic effects may improve visual sensitivity by promoting rhodopsin regeneration and inhibiting rhodopsin bleaching induced by light illumination. Zinc may activate the enzyme activity of retinol dehydrogenase and phosphodiesterase, while hypothermic effects may improve precursor transport, which is required for rhodopsin regeneration, by tightening membrane adhesion between retinas and retinal pigment epithelia. In addition, we believe that zinc treatment and hypothermic effects may work synergistically to accelerate visual sensitivity during visual adaptation.

A Case of Endophthalmitis after 25-gauge Transconjunctival Sutureless Vitrectomy

PURPOSE: To report a case of endophthalmitis after 25-gauge transconjunctival sutureless vitrectomy. METHODS: A 60-year-old male patient underwent 25-gauge transconjunctival sutureless vitrectomy through the epiretinal membrane. He was diagnosed as endophthalmitis on 7th postoperative day. Immediate vitrectomy and intravitreal antibiotics injection was done. RESULTS: Coagulase-negative staphylococcus was identified in vitreous culture and incarcerated vitreous through the previous unsutured sclerotomies were found. During vitrectomy, we found generalized retinal necrosis and vascular occlusion with retinal hemorrhage, cheese like thick membrane firmly adherent to the retina due to inflammatory response. The organism was sensitive to antibiotics administered. After treatment, inflammatory response was controlled and the retina became stable but the visual outcome was poor. CONCLUSIONS: Vitreous incarceration through unsutured sclerotomy may occur after 25-gauge transconjunctival sutureless vitrectomy. This can be a possible conduit for bacteria in the eye and be a cause of endophthalmitis. Sutureless sclerotomy should be carefully monitered and managed postoperatively.

Photodynamic Therapy for Choroidal Neovascularization Secondary to Age-Related Macular Degeneration

PURPOSE: To investigate the effects of repeated photodynamic therapy (PDT) for subfoveal choroidal neovascularization secondary to age-related macular degeneration (AMD) in Korean patients. METHODS: Clinical data of patients who were treated with repeated (3 times or more) PDT for subfoveal choroidal neovascularization secondary to AMD and followed up for more than 6 months were collected from 17 hospitals around the country. Visual outcomes at 12 and 24 months, follow-up were compared between subtypes of choroidal neovascularization. The factors related to final visual prognosis and PDT-related adverse effects were evaluated. RESULTS: 244 patients (244 eyes) were recruited (male: 60%, age: 67.7+/-9.1 years). The portion of patients with predominantly classic, minimally classic, and occult without classic choroidal neovascularization was 57%, 13%, and 24%, respectively and that of patients with visual improvements or less than moderate visual loss at 24 months follow-up were 28%, 38%, 30% and 47%, 56%, and 65%, respectively. Baseline visual acuity and age were significantly related to the final visual prognosis (p<0.05). PDT-related adverse events developed in 15 (6.1%) patients, but most were mild and transient. CONCLUSIONS: Repeated PDT for subfoveal choroidal neovascularization secondary to AMD has effects comparable to those of previous prospective, controlled trials without any significant safety concerns in Korea.

Neovascular Glaucoma after Vitrectomy for Proliferative Diabetic Retinopathy and the Ahmed Valve Implantation

PURPOSE: To evaluate the clinical features of neovascular glaucoma after vitrectomy for proliferative diabetic retinopathy and the effect of Ahmed valve implantation. METHODS: The medical records of 217 eyes of 178 patients who had undergone pars plana vitrectomy for proliferative diabetic retinopathy were reviewed. The clinical data on preoperative, intraoperative, and postoperative factors of these patients were compared with that of those who developed neovascular glaucoma (20 eyes of 18 patients) after vitrectomy. The effect and complications of Ahmed valve implantation were also reviewed. RESULTS: The type 1 diabetes, the presence of NVD, grade of NVE, grade of preoperative PRP, presence of postoperative vitreous hemorrhage, and postoperative tractional retinal detachment were significantly correlated with the development of neovascular glaucoma. Ahmed valve implantation in these patients was effective in controlling intraocular pressure and improving visual acuity. Complications of the Ahmed valve implantation were hyphema, tube exposure, recurrent vitreous hemorrhage, hypotony, and choroidal effusion. CONCLUSIONS: The risk factors for the development of neovascular glaucoma after vitrectomy for proliferative diabetic retinopathy were evaluated. Ahmed valve implantation in these patients is considered an effective treatment for controlling intraocular pressure.

The Development of Biodegradable Intrascleral Implant for Slow Releasing of Triamcinolone Acetonide

PURPOSE: In order to treat inflammatory and proliferative disorders of the posterior segment of the eye, the authors evaluated the use of a biodegradable intrascleral implant for slow release of triamcinolone acetonide (TA). METHODS: The intrascleral implant (1 mm thick and 3 mm in diameter) was made of alginic acid and PLA (poly (D, L-lactide)) containing 4 mg of TA. In vitro release of TA was evaluated by HPLC. To evaluate in vivo release of TA, the implant was placed into a scleral pocket in 18 rabbit eyes and the concentrations of TA in the aqueous humor, vitreous, and retina-choroid-sclera were measured by HPLC at 1, 2, 4, 8, and 12 weeks after implantation. The toxicity and biocompatibility of the implant were evaluated by slit lamp examination, IOP, electroretinogram, and light microscopy. RESULTS: In vitro study demonstrated that the implant released TA in controlled manner for at least 8 months. The TA detected in the vitreous after 8 to 12 weeks and was not detected in retina-choroid-sclera at 8 weeks after implantation. The TA was not detected in aqueous humor. No significant toxicity to the retina was observed. CONCLUSIONS: These results suggest that the intrascleral implant of TA could be a promising system for the delivery of steroids to the posterior segment of eye in cases of inflammatory or proliferative disorders of posterior segment.

Efficacy of Intravitreal Triamcinolone Acetonide Injections at the End of Pars Plana Vitrectomy in Proliferative Diabetic Retinopathy

PURPOSE: To evaluate the efficacy of intravitreal injections of triamcinolone acetonide (TA) at the end of pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR). METHODS: We analyzed 50 patients (52 eyes) who underwent PPV for treatment of PDR and received an intravitreal injection of 4 mg TA at the end of surgery. The study group (Group 1) was compared with a control group (Group 2, 46 patients, 51 eyes) (matched with the study group for preoperative parameters) who underwent PPV without intravitreal injection of TA. RESULTS: In Group 1, the grade of anterior chamber cells at postoperative days 1 and 7 was significantly lower than that of Group 2. There was slight mean IOP elevation in Group 1 at postoperative weeks 2, 3, 4, and 8, but it was not statistically significant. Forty-four eyes (84.6%) from Group 1 showed better visual acuity at the last follow-up than at the preoperative visit (Group 1). Thirty-two eyes (62.8%) from Group 2 showed better visual acuity at the last follow-up than at the preoperative visit. The degree of visual improvement was 0.75 logMAR in Group 1 and 0.59 logMAR in Group 2. Vitreous hemorrhage occurred in 9 eyes (17.3%) from Group 1 and in 19 eyes (37.3%) from Group 2. However, the differences in the occurrence of neovascularization in iris and neovascular glaucoma between two groups were not statistically significant. CONCLUSIONS: Intravitreal TA injection at the end of PPV seems to be effective in improving visual acuity and decreasing early postoperative inflammation and the frequency of vitreous hemorrhage.