Background: Hearing loss (HL) is one of the most common sensory disorders, affecting over 5-8% of the world's population. Approximately half of HL cases are attributed to genetic factors. In hereditary deafness, about 75-80% is inherited through autosomal recessive inheritance, and common pathogenic genes include GJB2 and SLC26A4. Pathogenic variants in the SLC26A4gene are the leading cause of hereditary hearing loss in humans, second only to the GJB2 gene. Variants in the SLC26A4gene cause hearing loss, which can be non-syndromic autosomal recessive deafness (DFNB4, OMIM #600791) associated with enlarged vestibular aqueduct (EVA) or Pendred syndrome (Pendred, OMIM #605646). DFNB4 is characterized by sensorineural hearing loss combined with EVA or less common cochlear malformation defect. Pendred syndrome is characterized by bilateral sensorineural hearing loss with EVA and an iodine defect that can lead to thyroid goiter. Currently, it is known that EVA is associated with variants in the SLC26A4 gene and is a penetrant feature of SLC26A4-related HL. Predominant mutations in these genes differ significantly across populations. For instance, predominant SLC26A4 mutations differ among populations, including p.T416P and c.1001G>A in Caucasians, p.H723R in Japanese and Koreans, and c.919-2A>G in Han Taiwanese and Han Chinese. On the other hand, there has been no study of hearing loss related to SLC26A4 gene variants among Mongolians, which is the basis of our research. Aim: We aimed to identify the characteristics of the SLC26A4 gene variants in Mongolian people with Enlarged vestibular aqueduct and Mondini malformation. Materials and Methods: In 2022-2024, We included 13 people with hearing loss and enlarged vestibular aqueduct, incomplete cochlea (1.5 turns of the cochlea with cystic apex- incomplete partition type II- Mondini malformation) were examined by CT scan of the temporal bone in our study. WES (Whole exome sequencing) analysis was performed in the Genetics genetic-laboratory of the National Taiwan University Hospital. Results: Genetic analysis revealed 26 confirmed pathogenic variants of bi-allelic SLC26A4 gene of 8 different types in 13 cases, and c.919-2A>G variant was dominant with 46% (12/26) in allele frequency, and c.2027T>A (p.L676Q) variant 19% (5/26), c.1318A>T(p.K440X) variant 11% (3/26), c.1229C>T (p.T410M) variant 8% (2/26) ) , c.716T>A (p.V239D), c.281C>T (p.T94I), c.1546dupC, and c.1975G>C (p.V659L) variants were each 4% (1/26)- revealed. Two male children, 11 years old (SLC26A4: c.919-2A>G) and 7 years old (SLC26A4: c.919-2A>G:, SLC26A4: c.2027T>A (p.L676Q))had history of born normal hearing and progressive hearing loss. Conclusions 1. 26 variants of bi-allelic SLC26A4 gene mutation were detected in Mongolian people with EVA and Mondini malformation, and c.919-2A>G was the most dominant allele variant, and rare variants such as c.1546dupC, c.716T>A (p.V239D) were detected. 2. Our study shows that whole-exome sequencing (WES) can identify gene mutations that are not detected by polymerase chain reaction (PCR) or NGS analysis.

Purpose: To analyze anterior, posterior, and total corneal refractive profiles and thickness using anterior segment (AS) sweptsource optical coherence tomography (SS-OCT) in Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) patients. Methods: This retrospective study compared 23 eyes from 14 patients with SJS/TEN with 23 eyes from 14 age- and sexmatched controls. AS SS-OCT measured corneal refractive profiles and pachymetry. Parameters included anterior, posterior, and total corneal power values, posterior to anterior curvature ratio, maximal corneal power, and thickness profiles. The SJS/TEN group was subdivided based on corneal opacity presence (subgroup A) or absence (subgroup B). Results: The SJS/TEN group showed significantly higher corneal astigmatism and maximal corneal power values for both anterior and posterior curvatures. Steep total corneal power and total corneal astigmatism were higher in the SJS/TEN group. The thinnest corneal thickness was lower, and its distance from the corneal vertex was greater in the SJS/TEN group. Subgroup analysis revealed that these differences were primarily attributed to the presence of corneal opacity. Additionally, automated keratometry of the anterior corneal surface showed significantly higher values, including steep, flat, and average keratometry and corneal astigmatism, in the SJS/TEN group. Conclusions AS SS-OCT shows significant alterations in both anterior and posterior corneal curvatures in patients with SJS/TEN. These findings emphasize the importance of considering posterior corneal curvature changes in pre-cataract surgery assessments and contact lens prescriptions for patients with SJS/TEN.

Purpose: This study evaluated the objective changes in the contralateral eye after unilateral cataract surgery. Methods: The study was designed as retrospective observational study. It included 44 patients who underwent unilateral cataract surgery. Collected data were uncorrected and corrected visual acuity, spherical equivalent, intraocular pressure, contrast sensitivity (CS), stereoacuity, and anterior segment optical coherence tomography parameters. Data were collected preoperatively, and 1 week and 1 month postoperatively for each eye. Results: Following unilateral cataract surgery, the pupil size of the fellow eye decreased from 3.46 mm to 3.17 mm (postoperative week 1, p = 0.003) and 3.08 mm (postoperative month 1, p < 0.001). Anterior chamber depth of the fellow eye increased significantly from 3.16 mm to 3.27 mm (postoperative week 1, p = 0.005) and 3.26 mm (postoperative month 1, p = 0.001). Uncorrected distance visual acuity (UDVA) of the fellow eye improved significantly at postoperative week 1 (p = 0.042) and postoperative month 1 (p = 0.044). Change of UDVA of the fellow eye at postoperative month 1 was significantly correlated with that of the treated eye (p = 0.039). Conclusions Anterior chamber structures changed and UDVA improved in the contralateral eye after unilateral cataract surgery in our cohort. Because fellow eyes were positively affected by monocular cataract surgery, it would be good information if planning for unilateral cataract surgery due to inevitable reasons.

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.

In frontal sinus surgery, stenosis of the frontal sinus opening after surgery remains a challenge for many surgeons. Different surgical approaches such as Lynch procedure, Draf type II, and extended modified Lothrop procedure may decrease adverse surgical results but also accompany inherent complications. The use of various kinds of stents have been also suggested to prolong the patency of the frontal sinus opening. However, no definite consensus has been reached about frontal stents use. Here we introduce the experience of using a new omega shaped silicon stent, which has shown promising results in keeping the frontal sinus opening patent.

Essential medical care is a concept referring to indispensable medical care. World Health Organization has defined essential healthcare services as the evidence-based technologies needed to cost-effectively solve health problems. However, most countries have no such term that describes essential healthcare services. Rather, it has been used to efficiently allocate medical resources in countries with limited resources. Therefore, a clear definition of essential healthcare services must be accompanied by a specific purpose and a clear direction for the need. The target to whom medical services are to be provided, the region and institution to be provided, the content of medical services, and the purpose of provision should be distinguished. Recently, as public interest in essential healthcare services has increased, the government announced “the Essential Healthcare Policy Package” and “the 1st Healthcare Reform Implementation Plan” to specifically promote it. But concerns of feasibility and financial estimates are being raised. So, here, I analyze the government policy package and its 1st implantation plan, and suggest policy proposals for them.

Objective: To compare coronary artery dimension-adjusted subtended myocardial mass between patients with hypertrophic cardiomyopathy (HCM) and a normal population without detectable atherosclerosis, and between HCM patients with and without chest pain. Materials and Methods: Twenty-five patients with HCM but no detectable atherosclerosis on coronary computed tomography angiography (CCTA) were included in the study. This group comprised 14 patients with chest pain and 11 patients without chest pain. They were matched with 25 healthy participants based on sex, age, coronary dominance pattern, and body surface area. The minimal lumen area (MLA) and subtended myocardial volume (V sub) were assessed in the left main (LM), proximal left anterior descending (pLAD), proximal left circumflex (pLCx), and proximal right coronary (pRCA) arteries. Additionally, an index of the subtended myocardial mass adjusted for the MLA, calculated as V sub/MLA 2 , was determined. Results: MLA was significantly larger in patients with HCM compared to the control group in LM (20.93 ± 6.31 mm 2 vs.15.24 ± 3.90 mm 2 , P< 0.001), pLAD (14.28 ± 3.55 mm 2 vs. 11.36 ± 2.07 mm 2, P = 0.001), pLCx (10.94 ± 3.60 mm 2 vs. 9.15 ± 2.93 mm 2 , P = 0.045), and pRCA (13.41 ± 4.85 mm 2 vs. 11.22 ± 3.20 mm 2 , P = 0.018). Despite an increase in coronary luminal area, patients with HCM exhibited significantly higher V sub/MLA 2 compared to the control group in both the pLAD (403.56 ± 200.35 mm -1 vs. 241.70 ± 85.87 mm -1 , P < 0.001) and the pRCA (186.06 ± 95.07 mm -1 vs. 125.07 ± 70.18 mm -1 , P= 0.007). V sub/MLA 2 was significantly elevated in patients with chest pain compared to those without in the pLAD (473.75 ± 227.38 mm -1 vs. 314.24 ± 110.74 mm -1 , P = 0.018) and the pLCx (417.04 ± 182.65 mm -1 vs. 275.29 ± 112.97 mm -1 , P = 0.044). Conclusion CCTA-derived V sub/MLA 2 may more accurately reflect the balance between myocardial blood supply and demand, offering insights into the occurrence of demand angina in patients with HCM without obstructive coronary artery disease.

Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.