Hoon Dong Kim

Functional Evaluation Using Multifocal Electroretinogram After Selective Retina Therapy With a Microsecond-Pulsed Laser

PURPOSE To evaluate the changes of retinal function with multifocal electroretinogram (mfERG), and estimate the association between functional and structural changes after selective retina therapy (SRT) with microsecond-pulsed laser in comparison to continuous wave laser photocoagulation (cwPC). METHODS Selective retina therapy and cwPC were applied with 10 × 10 shots and 1/2 lesion-width on the retina in the right and left eyes of 20 healthy Chinchilla Bastard rabbits, respectively. Optical coherence tomography (OCT), fundus fluorescein angiography (FFA), and mfERG were performed before, and on days 1, 7, and 30 after both laser treatments. The mean ratios of amplitudes and implicit times of N1 and P1 from eight hexagons covering laser-treated retinal lesions/total retina were measured. Histology was obtained after killing three rabbits at each time period to observe the anatomic changes after both laser treatments. RESULTS The mean ratios of amplitudes of N1 and P1 in SRT lesions did not change significantly for 30 days after laser treatment. Only subtle reductions of the mean ratios of N1 and P1 amplitudes on day 1, thereafter the amplitudes showed the trend to recover toward baseline values. Histology and OCT revealed temporary and reversible morphologic changes after SRT, which restored to normal within 1 month. However, the mean ratios of N1 amplitudes on days 7 and 30 (P = 0.010, P < 0.001, respectively), and P1 amplitudes on days 7 and 30 (P < 0.001, P < 0.001, respectively) declined significantly in cwPC lesions compared with baseline. Disorganization and atrophic changes were identified on histology and OCT after cwPC. CONCLUSIONS The results suggest that SRT preserved retinal function as well as anatomical structure after treatment.

Supermaximal Recession and Resection in Large-Angle Sensory Exotropia

In cases of extropia with an exodeviation angle over 50 prism diopter (PD), a 3- or 4-muscle surgery is a rational option. But, in patients with sensory exotropia, there is usually a strong preference for a monocular procedure to avoid surgery on the single seeing eye. Thus, we confined surgery to visually poor eyes, and performed a medial rectus muscle resection with a mean of 10.3 mm (range, 9-11 mm) and a lateral rectus muscle recession with a mean of 12.8 mm (range, 10-14 mm) in 4 adult sensory exotropia patients who had a mean deviation of 82.3 PD (range, 75-90 PD). The mean postoperative angle of exodeviation was 2.0 PD (range, ortho-8 PD). The limitation on abduction was not disfiguring. Other expected disfigurements, such as narrowing of the palpebral fissure or enophthalmos, were not conspicuous. The mean follow-up period was 4.5 months (range, 3-7 months). In large-angle sensory exotropia, instead of additive surgery on the seeing eye, supermaximal medial rectus resection and lateral rectus recession only on the visually poor eye is a clinically feasible surgical option.

Sclerotomy Site Leakage According to Wound Shape in 23-Gauge Microincisional Vitrectomy Surgery

Purpose: To compare the shape and self-sealing nature of scleral incision sites according to bevel shape and trocar blade direction in 23-gauge microincisional vitrectomy surgery. Methods: Twenty-three-gauge microincisional vitrectomies were performed in 60 eyes using a single-step entry system (Alcon Surgical, USA) and a 23-gauge two-step Eckardt vitrectomy system (DORC, the Netherlands). Trocar cannula were inserted using trocar blades bevel-up (20 eyes) or bevel-down (20 eyes). In 20 eyes, trocars were inserted after sclerotomies were performed using a microvitreoretinal (MVR) blade. After removing the cannula, we compared the scleral wound shapes and looked for leakage. Results: A total of 180 sclerotomies were done: 60 in the bevel-up direction (group 1), 60 in the bevel-down direction (group 2), and 60 using an MVR blade (group 3). Bevel-up insertion produced a V-shaped sclerotomy wound, whereas bevel-down insertion produced a reverse V-shaped wound. The MVR blade produced a slit-shaped wound. Wound leakage was identified in 21 V-shaped wounds, seven reverse V-shaped wounds, and four slit-shaped wounds. We observed no cases of hypotony, vitreous incarceration, or endophthalmitis. Conclusions: The self-sealing effect of slit-shaped wounds and reverse V-shaped wounds was superior to that of V-shaped wounds.

Clinical Applications of Photopic Negative Response (PhNR) for the Treatment of Glaucoma and Diabetic Retinopathy

Purpose To determine the clinical utility of using photopic negative response (PhNR) by comparing the parameters for normal, primary open angle glaucoma (POAG) and diabetic retinopathy (DR). Methods Electroretinography (UTAS E-3000) was performed in 12 normal, 12 POAG, and 12 DR subjects. Amplitudes and implicit times for PhNR were compared among the three groups. The mean deviation (MD) and pattern standard deviation (PSD) were evaluated using standard automated perimetry (SAP). The mean retinal nerve fiber layer (RNFL) thickness and cup-disc ratio were measured using optical coherence tomography. Results The a-waves and b-waves were not different among the three groups. However, compared to normal subjects, the PhNR amplitudes were reduced, and the PhNR implicit times were prolonged in the POAG and DR patients (p<0.001, p<0.001). The MD and RNFL thickness were correlated with the amplitudes and implicit times for the PhNR. Conclusions PhNR may be useful for the detection of inner retinal dysfunction, which is seen in patients who have glaucoma or diabetic retinopathy.

Time-Dependent Changes of Cell Proliferation After Laser Photocoagulation in Mouse Chorioretinal Tissue.

PURPOSE This study investigated the time course of cell proliferation after laser photocoagulation and analyzed the cell types of proliferating cells. METHODS C57BL/6J mice received unilateral laser photocoagulation. Intraperitoneal bromodeoxyuridine (BrdU) injection was performed, and mice were divided into two groups according to the injection paradigm: group 1 with continuous injection and group 2 with periodic injection. Each group was again divided into four subgroups according to injection period: 0 to 3 days (n = 11), 0 to 7 days (n = 14), 0 to 14 days (n = 6), and 0 to 28 days (n = 6) after laser photocoagulation for group 1; and 0 to 3 days (n = 11), 4 to 7 days (n = 6), 8 to 14 days (n = 6), and 15 to 28 days (n = 6) after laser photocoagulation for group 2. The eyes were examined with immunohistochemistry using anti-BrdU antibody and other various antibodies for identification of proliferating cells. Manual cell counting and flow cytometry were performed for quantification. RESULTS In group 1, the number of BrdU+ cells showed marked increase during the first 3 days of laser lesioning, reaching its maximum after 7 days (P < 0.05). Group 2 also demonstrated peak proliferation during the first 3 days, but a significantly reduced number of BrdU+ cells were detected during 4 to 7 days, 8 to 14 days, and 15 to 28 days of laser treatment (P < 0.05). BrdU+ cells colocalized with CD11b, F4/80, iba1, RPE65, CD31, and glial fibrillary acidic protein (GFAP) labeling, and CD11b+, F4/80+, and iba1+ cells constituted the main fraction of BrdU+ cells. CONCLUSIONS Laser photocoagulation induced cell proliferation mostly during the first 3 days, and many proliferating cells were identified as inflammatory cells, RPE cells, endothelial cells, and Müller cells.

Combined therapy with intravitreal bevacizumab and posterior subtenon triamcinolone acetonide injection in diabetic macular oedema

elevated white blood cell count (21.8 9 10/l, reference interval: 3.5– 8.8 10/l), C-reactive protein (36 mg/l, reference value <10 mg/l), elevated serum titres of antineutrophilocyte cytoplasmic antibodies c-ANCA (antiproteinase-3, IgG) (34 kU/l reference value <2.0 kU/l). A thorax X-ray showed cavitating pulmonary nodules, and a combined positron emission tomography and computed tomography (PET/CT) scan detected multiple metabolically active lung lesions corresponding to the radiographic lesions. Diagnosis of WG was established, and immunosuppresive treatment with rituximab, methotrexate and prednisolone was started. WG is a systemic inflammatory disease with ocular and orbital involvement in 28–87%, with necrotizing sclerokeratitis and orbital inflammation being the two most characteristic ocular presentations (Harman & Margo 1998). Diagnosis is based on the presence of nasal or oral inflammation, abnormal chest radiograph, abnormal urinary sediment and granulomatous inflammation on biopsy from involved tissue (Leavitt et al. 1990). Detection of c-ANCA has high sensitivity (85–96%) and specificity (Harman & Margo 1998). Primary surgically induced necrotizing scleritis (SINS) occurs rarely and demonstrates granulomatous scleral inflammation with an average latency of 9 months. After strabismus surgery, SINS exhibits a predilection for the area anterior to the lateral rectus insertion (O’Donoghue et al. 1992). SINS can be associated with peroperative infection. Sterile scleral melting can occur in patients with autoimmune diseases, such as rheumatoid arthritis, Wegener’s granulomatosis, relapsing polychondritis, systemic lupus erythematosus, polyarteritis nodosa, inflammatory bowel disease, diabetes mellitus and thyroid disorders (O’Donoghue et al. 1992). Scleral surgery and use of polyglactin suture (Salamon et al. 1982) may have precipitated scleritis in our patient who subsequently was diagnosed with WG. In patients with a history of orbital inflammatory disease, late necrotizing scleritis should be considered a possible complication of scleral surgery, even if no evident inflammation exists at the time of surgery. References

Exotropia caused by pit viper snakebite.

Pit viper snake venom exerts a mildly neurotoxic effect that may rarely lead to neurotoxic complications, such as paralytic strabismus. Extraocular muscles are known to be particularly susceptible to this complication. In previously reported cases, the medial rectus muscle has been the most frequently involved. We report the first case of a pit viper snakebite resulting in comitant exotropia without obvious paralytic features.

A Novel Pathogenic RS1 Variant (c.362delA) in a Korean Patient With Late-onset X-linked Retinoschisis

Eung Suk Lee, M.D.*, Mi-Ae Jang, M.D.*, Hoon Dong Kim, M.D., Jong Eun Park, M.D., Jong-Won Kim, M.D., and Young-Hoon Ohn , M.D. Department of Ophthalmology, Soonchunhyang University College of Medicine, Cheonan, Korea; Department of Laboratory Medicine and Genetics, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea; Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Department of Ophthalmology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea

En face optical coherence tomography findings in a case of Alport syndrome

Alport syndrome is a rare hereditary disease that is associated with retinal abnormalities such as dot-and-fleck retinopathy and temporal macular thinning. The main pathophysiological process of Alport syndrome is loss of the collagen network in the basement membrane. However, the alterations in each retinal layer have not been fully evaluated. In the case presented here, we evaluated the retina of a patient with Alport syndrome using en face optical coherence tomography (OCT). The findings suggested that the primary alterations occur in the internal limiting membrane and the retinal pigment epithelium basement membrane which is a part of the Bruchs membrane. The adjacent retinal layers are damaged subsequently. In conclusion, en face OCT could be useful in evaluating retinal abnormalities and understanding their underlying pathophysiology in Alport syndrome.

Effects of repeated intravitreal bevacizumab injections on the inner retinal function in neovascular age-related macular degeneration

Effects of repeated intravitreal bevacizumab injections on the inner retinal function in neovascular age-related macular degeneration