Yong Koo Koo Kang

Dr. Yong Koo Koo Kang

Department of Ophthalmology, Kyungpook National University School of Medicine
orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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5 April 2019 in PLOS ONE
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Journal Article
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HYHyun-Lim Yang
Hyun-Lim Yang
JKJong Jin Kim
Jong Jin Kim
YKYong Koo Koo Kang
Yong Koo Koo Kang
DPDong Ho Park
Dong Ho Park
HPHan Sang Park
Han Sang Park
MKMin-Soo Kim
Min-Soo Kim
Age-related macular degeneration (AMD) is the main cause of irreversible blindness among the elderly and require early diagnosis to prevent vision loss, and careful treatment is essential. Optical coherence tomography (OCT), the most commonly used imaging method in the retinal area for the diagnosis of AMD, is usually interpreted by a clinician, and OCT can help diagnose disease on the basis of the relevant diagnostic criteria, but these judgments can be somewhat subjective. We propose an algorithm for the detection of AMD based on a weakly supervised convolutional neural network (CNN) model to support computer-aided diagnosis (CAD) system. Our main contributions are the following three things. (1) We propose a concise CNN model for OCT images, which outperforms the existing large CNN models using VGG16 and GoogLeNet architectures. (2) We propose an algorithm called Expressive Gradients (EG) that extends the existing Integrated Gradients (IG) algorithm so as to exploit not only the input-level attribution map, but also the high-level attribution maps. Due to enriched gradients, EG can highlight suspicious regions for diagnosis of AMD better than the guided-backpropagation method and IG. (3) Our method provides two visualization options: overlay and top-k bounding boxes, which would be useful for CAD. Through experimental evaluation using 10,100 clinical OCT images from AMD patients, we demonstrate that our EG algorithm outperforms the IG algorithm in terms of localization accuracy and also outperforms the existing object detection methods in terms of class accuracy.

17 January 2020 in Scientific Reports
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YKYong Koo Koo Kang
Yong Koo Koo Kang
HPHan Sang Park
Han Sang Park
DPDong Ho Park
Dong Ho Park
JSJae Pil Shin
Jae Pil Shin
The purpose of this study was to investigate the incidence of secondary epiretinal membrane (ERM) after intravitreal injection and the effect of ERM on visual acuity and central macular thickness (CMT) in patients with diabetic macular edema (DME). We included 147 eyes of 95 patients over 18 years old who were diagnosed with DME from 2012 to 2016, treated with intravitreal injection, and followed-up more than 24 months. Mean CMT in the ERM group was significantly thicker than in the non-ERM group after 9, 12, 18, and 24 months. Secondary ERM developed in 9.5% of patients during follow-up. Compared to other agents, the incidence of secondary ERM was significantly higher after intravitreal injection of dexamethasone implant. Among patients in the ERM group, the mean decrease of CMT between pre-injection and 2 weeks post-injection was significantly less after secondary ERM formation than before ERM formation. Secondary ERM formation was significantly associated with the number of intravitreal injections and the use of dexamethasone implant. Therefore, secondary ERM develops more frequently as the number of intravitreal injections increases and after intravitreal dexamethasone implant injection. The therapeutic effects of intravitreal injections for DME patients decrease after secondary ERM formation.

12 April 2017 in Journal of Ophthalmology
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Journal Article
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YKYong Koo Koo Kang
Yong Koo Koo Kang
MKMyung Jun Kim
Myung Jun Kim
HKHong Kyun Kim
Hong Kyun Kim
BCBo Young Chun
Bo Young Chun
Purpose. To study the correlation between ocular parameters and subjective pain that patients perceived during phacoemulsification.Methods. Medical records of 142 patients who underwent standard phacoemulsification under topical anesthesia between March and August 2016 were retrospectively reviewed. The pain during phacoemulsification and 1 h after surgery was assessed and compared using a visual analog scale. In addition, demographic data, preoperative biometric parameters, and intraoperative surgical parameters were recorded.Results. Mean age of patients was 67.49 ± 12.50 years. The mean pain score was 2.26 ± 0.85 during phacoemulsification and 0.40 ± 0.69 postoperatively. Intraoperative pain was significantly associated with higher preoperative intraocular pressure (β = 0.220,P=0.016), greater anterior chamber depth (β = 0.210,P=0.028), and greater axial length (β = 0.181,P=0.043).Conclusions. To reduce the subjective pain when patients have high preoperative intraocular pressure, large anterior chamber depth, or great axial length, supplementary procedures may be required.

13 December 2023 in Scientific Reports
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JDJae Rok Do
Jae Rok Do
DPDong Ho Park
Dong Ho Park
JSJae Pil Shin
Jae Pil Shin
YKYong Koo Koo Kang
Yong Koo Koo Kang
This study aimed to analyze the duration and causes of persistent subretinal fluid (PSF) after scleral buckle (SB) surgery in patients with macula-involving rhegmatogenous retinal detachment (RRD). Sixty-one eyes of 61 patients with macula-involving RRD who underwent SB surgery between 2016 and 2022 were reviewed retrospectively. PSF was confirmed on optical coherence tomography. The PSF duration after surgery and the analysis of relevant ocular and systemic factors were conducted according to the PSF duration. The mean duration of PSF was 5.9 ± 4.6 months in all eyes and 8.1 ± 5.0 months in eyes not treated with external subretinal fluid (SRF) drainage, which was significantly longer than 4.5 ± 3.7 months in those subjected to external SRF drainage. The mean best-corrected visual acuity improved significantly 3 months after surgery. There were significant visual improvements in the external SRF drainage group compared to the non-drainage group during all follow-up periods. Longstanding shallow RRD was significantly associated with longer PSF duration after SB surgery. External SRF drainage during SB surgery can effectively reduce SRF, shorten the duration of PSF, and accelerate visual improvement.

16 July 2021 in RETINAL Cases & Brief Reports
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Journal Article
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YKYong Koo Koo Kang
Yong Koo Koo Kang
HPHan Sang Park
Han Sang Park
Purpose: To report a case of exudative perifoveal vascular anomalous complex treated with a 532-nm subthreshold micropulse laser unresponsive to intravitreal injections. Methods: A case report. Results: A 65-year-old woman presented with blurred vision in the left eye for 1 month. An isolated perifoveal aneurysm surrounded by retinal hemorrhages and hard exudates was revealed in fundus examination, and optical coherent tomography showed a round lesion with a hyperreflective wall, subretinal fluid, and an intraretinal cyst. She was diagnosed with exudative perifoveal vascular anomalous complex and received four intravitreal injections. However, her best-corrected visual acuity decreased, and an aneurysmal lesion with macular edema persisted for approximately 6 months. Three sessions of 532-nm subthreshold micropulse laser therapy around the aneurysm were applied because the intravitreal injection treatment was ineffective. Since the last session, macular edema disappeared, the involuted lesion remained substantially stable without recurrence, and her best-corrected visual acuity improved without visual field defect. Conclusion: To our knowledge, this is the first report of a successful subthreshold micropulse laser treatment for an exudative perifoveal vascular anomalous complex lesion, and it could be a safe and effective method for the patient unresponsive to intravitreal injections.

17 December 2021 in Journal of Clinical Medicine
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Journal Article
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YKYong Koo Koo Kang
Yong Koo Koo Kang
JSJae Pil Shin
Jae Pil Shin
(1) Background: We analyzed the duration of persistent subretinal fluid (PSF) and the contributing factors of PSF after pars plana vitrectomy in patients who had a macula with diabetic tractional retinal detachment (TRD). (2) Methods: Forty eyes of 40 patients who had pars plana vitrectomy due to a macula with diabetic TRD, between 2014 and 2020, were retrospectively reviewed. The duration of PSF, as well as relevant ocular and systemic factors, was analyzed. (3) Results: The mean duration of PSF was 4.4 ± 4.7 months. The prevalence of PSF was 75.0% at 1 month, 50.0% at 3 months, 30.0% at 6 months and 10.0% at 12 months after surgery. Blood urea nitrogen, creatinine, and estimated glomerular filtration rate (eGFR) were significantly associated with the duration of PSF in the univariate analysis. In the multivariate analysis, only eGFR was significantly associated with the duration of PSF (β = −0.089, p = 0.030). (4) Conclusion: PSF may persist for more than 12 months in a macula with diabetic TRD after vitrectomy. Moreover, patients with impaired kidney function tended to have a delayed subretinal fluid absorption. Therefore, careful investigation of preoperative systemic conditions, especially kidney function, should be considered before TRD surgery in diabetic patients.