Byung Gil Moon

Optical Coherence Tomography Angiography of DME and Its Association with Anti-VEGF Treatment Response.

PURPOSE To investigate the structural integrity of the superficial capillary plexuses (SCPs) and deep capillary plexuses (DCPs) using optical coherence tomography (OCT) angiography (OCTA) in patients with diabetic macular edema (DME) and its association with the response to anti-vascular endothelial growth factor (VEGF) treatment. DESIGN Retrospective, case-control study. PARTICIPANTS We included 51 DME eyes with a poor response to anti-VEGF agents and 32 age-matched DME eyes with a good response to anti-VEGF treatment, along with 20 fellow eyes without DME from the cases and controls. METHODS The medical records, including OCTA and spectral-domain OCT (SD OCT), were reviewed and compared between the groups. En face OCTA images of the SCP and DCP were obtained for each eye. An anti-VEGF responder was defined by a reduction of more than 50 μm in central retinal thickness after 3 consecutive anti-VEGF treatments. A poor responder was defined by a reduction of less than 50 μm or an increase in central retinal thickness after 3 monthly injections. MAIN OUTCOME MEASURES We measured the vascular density and foveal avascular zone (FAZ) area and counted the number of microaneurysms in each layer. The SD OCT images were compared with OCTA findings. RESULTS Compared with non-DME eyes, DME eyes had a lower vascular density (P < 0.001) and larger FAZ area (P < 0.001) in the DCP and more microaneurysms (P < 0.001) in both layers. Although there was no significant difference in the SCP between anti-VEGF responders and poor responders, poor responders tended to show greater damage and more microaneurysms in the DCP (P < 0.001) and a larger FAZ area (P < 0.001). The topographic location of the disrupted synaptic portion of the outer plexiform layer (OPL) in SD OCT exactly corresponded to the nonflow area of the DCP in OCTA. CONCLUSIONS Compared with DME eyes that responded to anti-VEGF treatment, poor responders show significant damage to the integrity of the DCP, but not the SCP. The degree of OPL disruption in SD OCT corresponds well with the extent of DCP loss in DME eyes. The extent of DCP loss and the corresponding OPL disruption could be useful predictors of responsiveness to anti-VEGF treatment.

Assessment of Macular Function for Idiopathic Epiretinal Membranes Classified by Spectral-Domain Optical Coherence Tomography

PURPOSE To evaluate the functional changes in various morphologic types of idiopathic epiretinal membrane (ERM) by multifocal electroretinography (mfERG) and spectral-domain optical coherence tomography (SD-OCT). METHODS All patients (n = 71) with unilateral idiopathic ERM underwent complete ophthalmologic examination, including measurements of best-corrected visual acuity (BCVA), SD-OCT, and mfERG for both eyes. To classify idiopathic ERM by subtype, the morphologic characteristics of the foveal area on representative scanned images were assessed. The five subtypes by foveal SD-OCT morphology included fovea-attached ERM with outer retinal thickening and minimal inner retinal change (Group 1A), outer retinal inward projection and inner retinal thickening (Group 1B), and prominent thickening of inner retinal layer (Group 1C) and foveal sparing ERM with formation of macular pseudohole (Group 2A) and with schisislike, intraretinal splitting (Group 2B). RESULTS On mfERG, P1 amplitude density in the central ring (R1) and inter-eye (affected eye/fellow eye) response ratio of P1 amplitude density in R1 differed significantly among five groups (P = 0.032 and P = 0.022, respectively). In Group 1 patients, central subfield thickness (CST) and inner retinal layer thickness (IRT) on SD-OCT were strongly correlated with BCVA and P1 amplitude density in R1. A receiver operating characteristic (ROC) curve analysis showed that IRT had high predictive accuracy in distinguishing Groups 1A and 1B (area under the ROC curve [AUROC] = 0.966) and Groups 1B and 1C (AUROC = 1.000). CONCLUSIONS Multifocal electroretinography can be used to investigate the pathophysiology of ERM and to evaluate the degree of functional demise in the fovea on SD-OCT.

Prevalence and Risk Factors of Early-Stage Age-Related Macular Degeneration in Patients Examined at a Health Promotion Center in Korea

We evaluated the prevalence and risk factors for early age-related macular degeneration (AMD) in Koreans 50 yr of age or older who were examined at a single health promotion center. We retrospectively reviewed the records of 10,449 subjects who visited the center over a 6-month period. Fundus photography was performed on all subjects, and systematic risk factor analysis was conducted using a structured questionnaire. All patients (n = 322) were initially diagnosed with drusen or early AMD using fundoscopy; the control group (n = 10,127) were those yielding normal fundoscopy findings. The age- and gender-adjusted prevalence of early AMD was 3.08%. Advanced age, male gender, smoking status, hyperlipidemia, working outdoors, and residence in rural areas were all significantly associated with an increased risk for development of early AMD. Higher-level ingestion of fruit or herbal medication and an increased amount of exercise were associated with a lower risk of early AMD development. In our Korean cohort, consisting principally of relatively healthy, middle-class urban adults, the prevalence of early AMD was 3.08% that is similar to that reported in earlier epidemiological studies. Several modifiable risk factors such as smoking and hyperlipidemia are associated with the prevalence of early AMD in our cohort.

Characterization of peripapillary atrophy using spectral domain optical coherence tomography.

Purpose To characterize the features of peripapillary atrophy (PPA), as imaged by spectral-domain optical coherence tomography (SD-OCT). Methods SD-OCT imaging of the optic disc was performed on healthy eyes, eyes suspected of having glaucoma, and eyes diagnosed with glaucoma. From the peripheral β-zone, the retinal nerve fiber layer (RNFL), the junction of the inner and outer segments (IS/OS) of the photoreceptor layer, and the Bruchs membrane/retinal pigment epithelium complex layer (BRL) were visualized. Results Nineteen consecutive eyes of 10 subjects were imaged. The RNFL was observed in the PPA β-zone of all eyes, and no eye showed an IS/OS complex in the β-zone. The BRL was absent in the β-zone of two eyes. The BRL was incomplete or showed posterior bowing in the β-zone of five eyes. Conclusions The common findings in the PPA β-zone were that the RNFL was present, but the photoreceptor layer was absent. Presence of the BRL was variable in the β-zone areas.

Efficacy and Safety of a Dexamethasone Implant in Patients with Diabetic Macular Edema at Tertiary Centers in Korea.

Purpose. To evaluate the real-world efficacy and safety of the dexamethasone implant (DEX implant) in patients with diabetic macular edema (DME). Methods. Retrospective, multicenter, and noncomparative study of DME patients who were treated with at least one DEX implant. A total of 186 eyes from 165 patients were included. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), complications, and number of retreatments were collected. Data at baseline and monthly for 6 months were analyzed. Results. The average baseline BCVA and CRT were 0.60 LogMAR and 491.6 μm, respectively. The mean BCVA improved until 3 months and then decreased up to 6 months of follow-up (0.53, 0.49, and 0.55 LogMAR at 1, 3, and 6 months; p = 0.001, <0.001, and 0.044, resp.). The change of mean CRT was similar to BCVA (345.0, 357.7, and 412.5 μm at 1, 3, and 6 months, p < 0.001, <0.001, and <0.001, resp.). 91 eyes (48.9%) received additional treatment with anti-VEGF or DEX implant. The average treatment-free interval was 4.4 months. In group analyses, the DEX implant was more effective in pseudophakic eyes, DME with subretinal fluid (SRF), or diffuse type. Conclusions. Intravitreal dexamethasone implants are an effective treatment for patients with DME, most notably in pseudophakic eyes, DME with SRF, or diffuse type. A half of these patients require additional treatment within 6 months.

Macular Gradient Measurement in Myopic Posterior Staphyloma Using Optical Coherence Tomography

Purpose To evaluate clinical characteristics and the macular gradient in myopic posterior staphyloma with time domain (TD) optical coherence tomography (OCT). Methods Sixty-four staphyloma eyes of 40 patients were examined. Macular gradient (tangent θ) and the location of staphyloma were assessed with OCT imaging. The macular gradient was measured at points 1 mm and 2 mm distant from the fovea. The relationships of the macular gradient with age, axial length, and spherical equivalent were analyzed. Results In 8 eyes (12.5%), the bottoms of the staphylomas were in the fovea, and there was no macular gradient. However, in the other 56 eyes (87.5%), the bottoms of the staphylomas were not in the foveal area, and macular gradients existed. Staphylomas were commonly located in the infero-nasal retinal area. The mean macular gradient (tangent θ) was 0.26 ± 0.08 at 1 mm distance from the fovea and 0.28 ± 0.10 at 2 mm. No significant relationships were observed between macular gradient and axial length, patient age, or spherical equivalent. Conclusions TD OCT reveals staphyloma location. If the location is outside of the fovea, a macular gradient exists and can be measured by OCT. Axial length measurement error may occur in eyes with poor visual fixation and steep macular gradients.

Glaucoma Progression Detection by Retinal Nerve Fiber Layer Measurement Using Scanning Laser Polarimetry: Event and Trend Analysis

Purpose To evaluate the use of scanning laser polarimetry (SLP, GDx VCC) to measure the retinal nerve fiber layer (RNFL) thickness in order to evaluate the progression of glaucoma. Methods Test-retest measurement variability was determined in 47 glaucomatous eyes. One eye each from 152 glaucomatous patients with at least 4 years of follow-up was enrolled. Visual field (VF) loss progression was determined by both event analysis (EA, Humphrey guided progression analysis) and trend analysis (TA, linear regression analysis of the visual field index). SLP progression was defined as a reduction of RNFL exceeding the predetermined repeatability coefficient in three consecutive exams, as compared to the baseline measure (EA). The slope of RNFL thickness change over time was determined by linear regression analysis (TA). Results Twenty-two eyes (14.5%) progressed according to the VF EA, 16 (10.5%) by VF TA, 37 (24.3%) by SLP EA and 19 (12.5%) by SLP TA. Agreement between VF and SLP progression was poor in both EA and TA (VF EA vs. SLP EA, k = 0.110; VF TA vs. SLP TA, k = 0.129). The mean (±standard deviation) progression rate of RNFL thickness as measured by SLP TA did not significantly differ between VF EA progressors and non-progressors (-0.224 ± 0.148 µm/yr vs. -0.218 ± 0.151 µm/yr, p = 0.874). SLP TA and EA showed similar levels of sensitivity when VF progression was considered as the reference standard. Conclusions RNFL thickness as measurement by SLP was shown to be capable of detecting glaucoma progression. Both EA and TA of SLP showed poor agreement with VF outcomes in detecting glaucoma progression.

Improved Visual Outcome and Low Recurrence with Early Treatment with Intravitreal Anti-Vascular Endothelial Growth Factor in Myopic Choroidal Neovascularization.

Purpose: The aim of this study was to determine the correlation between the duration of myopic choroidal neovascularization (CNV) and treatment outcome after anti-vascular endothelial growth factor (VEGF) injections. Methods: We performed a retrospective review of treatment-naïve myopic CNV patients who were treated with anti-VEGF and followed for at least 24 months to identify factors predicting final outcome and recurrence. Results: Among 106 eyes, a shorter duration of CNV was a significant predictor of a better final best-corrected visual acuity, even after controlling for other factors (p = 0.042). When divided into 3 groups according to CNV duration before treatment (<2, 2-8, and 8-24 weeks), the recurrence rate (19, 25, and 52%, respectively; p = 0.006) and number of injections (3.5, 4.0, and 5.5, respectively; p = 0.021) were significantly lower in eyes with a shorter duration of CNV. Conclusions: Early anti-VEGF treatment of myopic CNV decreased the recurrence rate and number of injections and improved visual outcome.

Scleral Buckling Using a Non-contact Wide-Angle Viewing System with a 25-Gauge Chandelier Endoilluminator

Purpose To report the outcome of scleral buckling using a non-contact wide-angle viewing system with a 25-gauge chandelier endoilluminator. Methods Retrospective analyses of medical records were performed for 17 eyes of 16 patients with primary rhegmatogenous retinal detachment (RRD) without proliferative vitreoretinopathy who had undergone conventional scleral buckling with cryoretinopexy using the combination of a non-contact wide-angle viewing system and chandelier endoillumination. Results The patients were eight males and five females with a mean age of 26.8 ± 10.2 (range, 11 to 47) years. The mean follow-up period was 7.3 ± 3.1 months. Baseline best-corrected visual acuity was 0.23 ± 0.28 logarithm of the minimum angle of resolution units. Best-corrected visual acuity at the final visit showed improvement (0.20 ± 0.25 logarithm of the minimum angle of resolution units), but the improvement was not statistically significant (p = 0.722). As a surgery-related complication, there was vitreous loss at the end of surgery in one eye. As a postoperative complication, increased intraocular pressure (four cases) and herpes simplex epithelial keratitis (one case) were controlled postoperatively with eye drops. One case of persistent RRD after primary surgery needed additional vitrectomy, and the retina was postoperatively attached. Conclusions Scleral buckling with chandelier illumination as a surgical technique for RRD has the advantages of relieving the surgeons neck pain from prolonged use of the indirect ophthalmoscope and sharing the surgical procedure with another surgical team member. In addition, fine retinal breaks that are hard to identify using an indirect ophthalmoscope can be easily found under the microscope by direct endoillumination.