Yun Ha Lee

Frequency, Type and Cause of Artifacts in Swept-Source and Cirrus HD Optical Coherence Tomography in Cases of Glaucoma and Suspected Glaucoma

ABSTRACT Purpose: To evaluate and compare the frequency, type and cause of imaging artifacts incurred when using swept-source optical coherence tomography (SS OCT) and Cirrus HD OCT in the same patients on the same day. Materials and methods: From left eye OCT results of 72 patients, disc area and macular area data could be compared between the two types of OCT. For each scan, the final printout report and source data were examined. For comparison between the two types of OCT, only source image data were used because of differences in the final printout report format. Results: There were no significant differences in the artifact frequencies between the two groups in either area (disc area: 35.9% of SS OCT, 42.2% of Cirrus OCT, p = 0.523; Macular area: 24.2% of SS OCT, 22.7% of Cirrus OCT, p = 1.00). The overall results of artifact comparison between the two types of OCTs also showed no significant differences. Boundary misidentification was the most common type of artifact observed, and ocular pathology was the most common cause of artifact in both types of OCTs. Among ocular pathologies, the epiretinal membrane (ERM) was the most common cause of OCT artifact production in both types of OCTs. Conclusions: There was no significant difference in the frequency, type and cause of artifacts between SS OCT and Cirrus HD OCT. Artifacts in OCT can influence the interpretation of OCT results. In particular, ERM around the optic disc could contribute to OCT artifacts and should be considered in glaucoma diagnosis or during patient follow-up using OCT.

Estimated Prevalence of Glaucoma in South Korea Using the National Claims Database

Purpose. To estimate the prevalence of glaucoma and costs associated with glaucoma care in South Korea between 2008 and 2013 using the Korean national claims database. Design. Retrospective cross-sectional study from a national claims database. Methods. Patients who were diagnosed with glaucoma between 2008 and 2013 were retrospectively identified in the national claims database using glaucoma diagnostic codes. For each year, the prevalence of glaucoma and direct medical costs associated with glaucoma care were estimated. Result. The prevalence of glaucoma in patients ≥40 years of age increased from 0.79% in 2008 to 1.05% in 2013. The number of patients with glaucoma increased by 54% between 2008 and 2013 (9% average annual increase). The prevalence of glaucoma increased with age and was higher in males than in females. The cost to care for glaucoma patients increased from

Risk factors for visual field progression of normal-tension glaucoma in patients with myopia

16.5 million in 2008 to

Effect of trabeculectomy on the accuracy of intraocular lens calculations in patients with open-angle glaucoma

29.2 million in 2013, which translated into an 81% increase over the 6 years examined (12.7% average annual increase). Conclusion. The estimated prevalence and socioeconomic burden of glaucoma have steadily increased each year in South Korea. Nevertheless, many glaucoma patients remain undiagnosed in the present study using national claims database.

Influence of epiretinal membrane on the measurement of peripapillary retinal nerve fibre layer thickness using spectral-domain coherence tomography

OBJECTIVEnTo identify risk factors for visual field progression of normal-tension glaucoma (NTG) in patients with myopia.nnnDESIGNnLongitudinal, observational study.nnnPARTICIPANTSnFifty-one eyes of 51 NTG patients with myopia (less than -0.75D based on spherical equivalence) who had undergone visual field (VF) testing at least once per year for ≥6 years between November 2005 and December 2013.nnnMETHODSnProgression was defined using event-based guided progression analysis. Risk factors were analyzed using the Cox proportional hazards model and further tested for independence in a multivariate model.nnnRESULTSnThe mean observation period was 7.0 ± 1.3 years, and 16 of 51 subjects showed progression. In the univariate analysis, abnormal retinal nerve fibre layer (RNFL) colour codes (yellow or red sector) at the 11, 10, and 7 oclock positions on optical coherence tomography showed significant associations with the VF progression (p = 0.03, 0.03, and 0.01, respectively). In the final multivariate models, the abnormal RNFL colour code of the 7 oclock sector (inferotemporal sector) was the only significant risk factor for progression (hazard ratio = 4.07 and 4.37; 95% CI, 1.11-14.92 and 1.27-15.04; p = 0.03 and 0.02, respectively).nnnCONCLUSIONSnInferotemporal RNFL thinning could be a risk factor for progression in NTG patients with myopia.

Treatment Outcome of Triple Procedure in Open-Angle Glaucoma and Angle-Closure Glaucoma

The objective of the study is to examine the effect of trabeculectomy on intraocular lens power calculations in patients with open‐angle glaucoma (OAG) undergoing cataract surgery.

Glaucoma Surgery in Patients with Painful Blind Glaucomatous Eyes

Background/aims To investigate the effect of epiretinal membrane (ERM) on peripapillary retinal nerve fibre layer (RNFL) thickness measurements using spectral-domain optical coherence tomography (Spectralis; Heidelberg Engineering). Methods A total of 134 patients with idiopathic ERM and 63 healthy controls were included in this observational comparative study. We categorised ERMs into three severity grades, based on retinal appearance in macular scans. All eyes with ERM were classified into two groups; those involving the peripapillary scan area (ERM+pp, n=68 eyes) and not involving the peripapillary scan area (ERM−pp, n=66 eyes) using the macular disc scan. Peripapillary RNFL thickness was compared between related subgroups as (ERM+pp) or (ERM−pp) group. Results Temporal peripapillary RNFL thickness was significantly greater in the ERM+pp group (109.44±22.91u2005μm), followed by the ERM−pp (82.60±11.77u2005μm, p<0.001) and control (75.42±10.49u2005μm, p<0.001) groups. Temporal peripapillary RNFL thickness significantly increased with ERM grade in the ERM+pp and ERM−pp groups (both p<0.001). The peripapillary RNFL thickness was overestimated (exceeded 99th percentile) in the temporal sector in 49 eyes (72.1%) in the ERM+pp group and in 5 eyes (7.6%) in the ERM−pp group. Conclusions Temporal and global peripapillary RNFL thickness is significantly higher in eyes with ERM, especially when the ERM extends into the peripapillary area. However, some eyes with an ERM that does not involve the peripapillary scan area still show peripapillary RNFL thickening. Measured peripapillary RNFL thickness was significantly and positively correlated with ERM severity.