1.Effect of 50-Hz Filters on Pattern Electroretinogram
Dong Hee HA ; Nam Ju MOON ; Ungsoo Samuel KIM
Korean Journal of Ophthalmology 2025;39(3):241-245
Purpose:
Pattern electroretinogram (PERG) is used to evaluate the function of retinal ganglion cells. However, the amplitude of PERG is quite small, making the examination challenging to perform. Waveform noise may be minimized by applying various filters. We aimed to investigate the effect of 50-Hz filters on PERG test results.
Methods:
This is the retrospective observational study. PERG tests were performed using the RETI-scan system according to the International Society for Clinical Electrophysiology of Vision guidelines. Three types of 50-Hz filters (soft, middle, and hard) were applied. The differences in parameters (N35 peak time, P50 peak time, N95 peak time, P50 amplitude, N95 amplitude, and N95 to P50 ratio) were analyzed. Based on the provided normal range, the changes from normal to abnormal range or vice versa were investigated.
Results:
A total of 24 waveforms were analyzed. After filtering, the P50 and N95 amplitudes showed a significant reduction of 8% to 15% (P50 amplitude: 5.1 ± 2.7 μV without filter, 4.6 ± 2.3 μV with 50-Hz soft filter, 4.3 ± 2.1 μV with 50-Hz middle filter, 4.3 ± 2.1 μV with 50-Hz hard filter; N95 amplitude: 7.2 ± 4.2 μV without filter, 6.6 ± 3.8 μV with 50-Hz soft filter, 6.3 ± 3.6 μV with 50-Hz middle filter, 6.1 ± 3.6 μV with 50-Hz hard filter). This pattern was more prominent in normal subjects. All latencies except the N35 peak time exhibited no differences between the tests. The N95 to P50 ratio decreased after 50-Hz middle and hard filtering. Considering the normative data, switching between normal and abnormal results was rare.
Conclusions
Although peak time was not significantly affected, amplitude was significantly reduced after using 50-Hz filters. Thus, 50-Hz filters can smoothen the waveform. Nevertheless, caution must be exercised while taking readings.
2.Effects of Pancreatitis and Type 2 Diabetes Mellitus on the Development of Pancreatic Cancer: A Nationwide Nested Case-Control Study
Young-eun KIM ; Min Heui YU ; Chung Mo NAM ; Eun Seok KANG
Diabetes & Metabolism Journal 2025;49(2):252-263
Background:
Despite diabetes mellitus (DM) and pancreatitis being known risk factors for pancreatic cancer, patients with these conditions are not included in pancreatic cancer screening due to the low incidence of pancreatic cancer in these populations. This study aimed to determine the high-risk subgroup of patients with diabetes and pancreatitis that would benefit from pancreatic cancer screening.
Methods:
A nested case-control study was conducted using data from the National Health Information Database of the Korean National Health Insurance Service. Patients were categorized into the following groups: type 2 diabetes mellitus only (T2DM-only), pancreatitis-only (PAN-only), T2DM followed by pancreatitis (T2DM-PAN), post-pancreatitis diabetes mellitus (PPDM), and no diabetes and no pancreatitis (NDNP). Conditional logistic regression was used to determine significant associations of each group with pancreatic cancer development risk.
Results:
The risk of pancreatic cancer was significantly higher in the T2DM-PAN (adjusted odds ratio [AOR], 4.96; 95% confidence interval [CI], 4.48 to 5.49) and PPDM (AOR, 4.71; 95% CI, 4.12 to 5.37) groups than in the NDNP group. Compared to patients in the NDNP group, those with PPDM using insulin had a 17-fold increased risk (AOR, 16.72; 95% CI, 9.50 to 29.43), and individuals with PPDM who had diabetes for less than 3 years had a more than 8-fold increased risk of pancreatic cancer (AOR, 8.83; 95% CI, 5.99 to 13.01).
Conclusion
In patients with post-pancreatitis diabetes, insulin use or shorter duration of diabetes was associated with a higher risk of pancreatic cancer, suggesting that patients in these subgroups may require close monitoring for pancreatic cancer development.
4.Effect of 50-Hz Filters on Pattern Electroretinogram
Dong Hee HA ; Nam Ju MOON ; Ungsoo Samuel KIM
Korean Journal of Ophthalmology 2025;39(3):241-245
Purpose:
Pattern electroretinogram (PERG) is used to evaluate the function of retinal ganglion cells. However, the amplitude of PERG is quite small, making the examination challenging to perform. Waveform noise may be minimized by applying various filters. We aimed to investigate the effect of 50-Hz filters on PERG test results.
Methods:
This is the retrospective observational study. PERG tests were performed using the RETI-scan system according to the International Society for Clinical Electrophysiology of Vision guidelines. Three types of 50-Hz filters (soft, middle, and hard) were applied. The differences in parameters (N35 peak time, P50 peak time, N95 peak time, P50 amplitude, N95 amplitude, and N95 to P50 ratio) were analyzed. Based on the provided normal range, the changes from normal to abnormal range or vice versa were investigated.
Results:
A total of 24 waveforms were analyzed. After filtering, the P50 and N95 amplitudes showed a significant reduction of 8% to 15% (P50 amplitude: 5.1 ± 2.7 μV without filter, 4.6 ± 2.3 μV with 50-Hz soft filter, 4.3 ± 2.1 μV with 50-Hz middle filter, 4.3 ± 2.1 μV with 50-Hz hard filter; N95 amplitude: 7.2 ± 4.2 μV without filter, 6.6 ± 3.8 μV with 50-Hz soft filter, 6.3 ± 3.6 μV with 50-Hz middle filter, 6.1 ± 3.6 μV with 50-Hz hard filter). This pattern was more prominent in normal subjects. All latencies except the N35 peak time exhibited no differences between the tests. The N95 to P50 ratio decreased after 50-Hz middle and hard filtering. Considering the normative data, switching between normal and abnormal results was rare.
Conclusions
Although peak time was not significantly affected, amplitude was significantly reduced after using 50-Hz filters. Thus, 50-Hz filters can smoothen the waveform. Nevertheless, caution must be exercised while taking readings.
5.Effect of 50-Hz Filters on Pattern Electroretinogram
Dong Hee HA ; Nam Ju MOON ; Ungsoo Samuel KIM
Korean Journal of Ophthalmology 2025;39(3):241-245
Purpose:
Pattern electroretinogram (PERG) is used to evaluate the function of retinal ganglion cells. However, the amplitude of PERG is quite small, making the examination challenging to perform. Waveform noise may be minimized by applying various filters. We aimed to investigate the effect of 50-Hz filters on PERG test results.
Methods:
This is the retrospective observational study. PERG tests were performed using the RETI-scan system according to the International Society for Clinical Electrophysiology of Vision guidelines. Three types of 50-Hz filters (soft, middle, and hard) were applied. The differences in parameters (N35 peak time, P50 peak time, N95 peak time, P50 amplitude, N95 amplitude, and N95 to P50 ratio) were analyzed. Based on the provided normal range, the changes from normal to abnormal range or vice versa were investigated.
Results:
A total of 24 waveforms were analyzed. After filtering, the P50 and N95 amplitudes showed a significant reduction of 8% to 15% (P50 amplitude: 5.1 ± 2.7 μV without filter, 4.6 ± 2.3 μV with 50-Hz soft filter, 4.3 ± 2.1 μV with 50-Hz middle filter, 4.3 ± 2.1 μV with 50-Hz hard filter; N95 amplitude: 7.2 ± 4.2 μV without filter, 6.6 ± 3.8 μV with 50-Hz soft filter, 6.3 ± 3.6 μV with 50-Hz middle filter, 6.1 ± 3.6 μV with 50-Hz hard filter). This pattern was more prominent in normal subjects. All latencies except the N35 peak time exhibited no differences between the tests. The N95 to P50 ratio decreased after 50-Hz middle and hard filtering. Considering the normative data, switching between normal and abnormal results was rare.
Conclusions
Although peak time was not significantly affected, amplitude was significantly reduced after using 50-Hz filters. Thus, 50-Hz filters can smoothen the waveform. Nevertheless, caution must be exercised while taking readings.
6.Simultaneous Four-site Restoration of Bilateral Scleromalacia Using Autologous Tragal Perichondrium and Preserved Sclera
Yoonsoo NAM ; Seung Hyeun LEE ; Kyoung Woo KIM
Journal of the Korean Ophthalmological Society 2025;66(1):63-69
Purpose:
We report a case of bilateral nasal and temporal four-site scleromalacia following cosmetic conjunctivectomy, successfully managed with simultaneous restoration surgery at all four sites using autologous tragal perichondrium and preserved scleral graft.Case summary: A 56-year-old woman who underwent cosmetic conjunctivectomy on both eyes 15 years earlier, presented with intermittent eye pain. Examination revealed scleromalacia with calcium plaques in all four nasal and temporal scleral areas. The most extensive avascular area was in the nasal region of the right eye, and the most prominent uveal exposure was in the nasal area of the left eye. Considering the lesion and exposure sizes of the avascular zone and uvea exposure, preserved sclera was transplanted to the temporal and nasal areas of the right eye, while autologous tragal perichondrium was transplanted to the nasal area of the left eye. Tenon's capsule vessels were fixed with pedicle flaps in all four surgical areas for vascularization. Frozen amniotic membrane was transplanted in the nasal area of the left eye, where the conjunctival defect was substantial, and in the lateral area of the left eye, where no graft was used. The conjunctival epithelium was closed using autologous conjunctival flaps in all four areas. Post-surgery, successful engraftment and vascularization of the graft materials were observed in both eyes.
Conclusions
Even with multiple areas of scleromalacia in both eyes, successful results can be achieved during simultaneous surgery if an appropriate graft material is selected and the surgery is performed utilizing principles of tissue restoration.
7.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.
8.Effects of Pancreatitis and Type 2 Diabetes Mellitus on the Development of Pancreatic Cancer: A Nationwide Nested Case-Control Study
Young-eun KIM ; Min Heui YU ; Chung Mo NAM ; Eun Seok KANG
Diabetes & Metabolism Journal 2025;49(2):252-263
Background:
Despite diabetes mellitus (DM) and pancreatitis being known risk factors for pancreatic cancer, patients with these conditions are not included in pancreatic cancer screening due to the low incidence of pancreatic cancer in these populations. This study aimed to determine the high-risk subgroup of patients with diabetes and pancreatitis that would benefit from pancreatic cancer screening.
Methods:
A nested case-control study was conducted using data from the National Health Information Database of the Korean National Health Insurance Service. Patients were categorized into the following groups: type 2 diabetes mellitus only (T2DM-only), pancreatitis-only (PAN-only), T2DM followed by pancreatitis (T2DM-PAN), post-pancreatitis diabetes mellitus (PPDM), and no diabetes and no pancreatitis (NDNP). Conditional logistic regression was used to determine significant associations of each group with pancreatic cancer development risk.
Results:
The risk of pancreatic cancer was significantly higher in the T2DM-PAN (adjusted odds ratio [AOR], 4.96; 95% confidence interval [CI], 4.48 to 5.49) and PPDM (AOR, 4.71; 95% CI, 4.12 to 5.37) groups than in the NDNP group. Compared to patients in the NDNP group, those with PPDM using insulin had a 17-fold increased risk (AOR, 16.72; 95% CI, 9.50 to 29.43), and individuals with PPDM who had diabetes for less than 3 years had a more than 8-fold increased risk of pancreatic cancer (AOR, 8.83; 95% CI, 5.99 to 13.01).
Conclusion
In patients with post-pancreatitis diabetes, insulin use or shorter duration of diabetes was associated with a higher risk of pancreatic cancer, suggesting that patients in these subgroups may require close monitoring for pancreatic cancer development.
10.Effects of Pancreatitis and Type 2 Diabetes Mellitus on the Development of Pancreatic Cancer: A Nationwide Nested Case-Control Study
Young-eun KIM ; Min Heui YU ; Chung Mo NAM ; Eun Seok KANG
Diabetes & Metabolism Journal 2025;49(2):252-263
Background:
Despite diabetes mellitus (DM) and pancreatitis being known risk factors for pancreatic cancer, patients with these conditions are not included in pancreatic cancer screening due to the low incidence of pancreatic cancer in these populations. This study aimed to determine the high-risk subgroup of patients with diabetes and pancreatitis that would benefit from pancreatic cancer screening.
Methods:
A nested case-control study was conducted using data from the National Health Information Database of the Korean National Health Insurance Service. Patients were categorized into the following groups: type 2 diabetes mellitus only (T2DM-only), pancreatitis-only (PAN-only), T2DM followed by pancreatitis (T2DM-PAN), post-pancreatitis diabetes mellitus (PPDM), and no diabetes and no pancreatitis (NDNP). Conditional logistic regression was used to determine significant associations of each group with pancreatic cancer development risk.
Results:
The risk of pancreatic cancer was significantly higher in the T2DM-PAN (adjusted odds ratio [AOR], 4.96; 95% confidence interval [CI], 4.48 to 5.49) and PPDM (AOR, 4.71; 95% CI, 4.12 to 5.37) groups than in the NDNP group. Compared to patients in the NDNP group, those with PPDM using insulin had a 17-fold increased risk (AOR, 16.72; 95% CI, 9.50 to 29.43), and individuals with PPDM who had diabetes for less than 3 years had a more than 8-fold increased risk of pancreatic cancer (AOR, 8.83; 95% CI, 5.99 to 13.01).
Conclusion
In patients with post-pancreatitis diabetes, insulin use or shorter duration of diabetes was associated with a higher risk of pancreatic cancer, suggesting that patients in these subgroups may require close monitoring for pancreatic cancer development.

Result Analysis
Print
Save
E-mail