Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.

Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.

Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.

Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.

Purpose: To evaluate the effectiveness of an instrument devised for slit-lamp examination of donor corneas suspended in preservation medium. Methods: The study examined two donor corneas received at Yeouido St. Mary's Hospital in February 2023 and March 2023. The instrument has three main components: a plastic holder to hold the preservation medium bottle, a cube with a mirror for reflecting the slit beam, and a stand to attach the device to the slit-lamp. Using the instrument, the donor corneas were examined via slit-lamp: microscopy with the endothelium facing upward and downward. Specular microscopy and anterior segment optical coherence tomography (OCT) were also performed on the preserved donor corneas. Results: Slit-lamp examination of donor corneas in preservation medium using the instrument showed overall corneal buttoning and optical sections of the donor cornea. Using specular reflection and retroillumination, the endothelial layer was partially visible. However, specular microscopy and anterior segment OCT could not examine the donor cornea in preservation medium using the instrument. Conclusions The devised instrument facilitates slit-lamp examination of donor corneas in preservation medium, enabling a qualitative assessment of donor corneas before corneal transplantation surgery.

Purpose: In the present study, we determined the prevalence of obstructive meibomian gland dysfunction (MGD), hyposecretory MGD, grossly normal MG, and hypersecretory MGD in patients with dry eye syndrome using lipid layer thickness (LLT) and MG dropout. Methods: Eighty-eight patients with dry eye syndrome were included in the study. Patients were categorized into four groups according to the LLT and weighted total meiboscore. The proportion of patients in each group was calculated. The age, sex, Ocular Surface Disease Index, LLT, Schirmer, tear film breakup time, cornea stain, weighted total meiboscore, expressibility, and quality of meibum were compared between the four groups. Results: Fifteen eyes (17.0%) had obstructive MGD, two eyes (2.3%) had hyposecretory MGD, 40 eyes (45.5%) had grossly normal MG, and 17 eyes (19.3%) had hypersecretory MGD. The obstructive MGD group was younger than the grossly normal MG group. In obstructive MGD, the ratio of men to women was higher than that of the other groups. However, Ocular Surface Disease Index, Schirmer, tear film breakup time, and corneal stain did not show statistically significant differences between the four groups. The meibum expressibility of the hyposecretoy MGD group was worse than those of the other groups. The meibum expressibility of the hyposecretoy MGD group was poor than those of the obstructive and hypersecretory MGD group. Conclusions This categorization was expected to help determine the best treatment method for dry eye syndrome, according to the MG status.

Purpose: To introduce an intuitive method for measuring conjunctival microvascular blood flow velocity by imaging bulbar conjunctival microvessels using a slit-lamp biomicroscope equipped with a zoom lens and an ultra-high-speed camera. Methods: After obtaining consent from 10 patients (1 male, 9 females) who visited Yeouido St. Mary’s Hospital from August 21, 2020, to June 12, 2021, the patients were examined under a slit lamp microscope equipped with an ultra-high-speed camera and zoom lens. The blood flow in the conjunctival microvessels was photographed. The captured images were analyzed with ImageJ software to measure the blood flow velocity in the conjunctival microvessels, and we investigated whether the blood flow velocity correlated with the vessel diameter and age. Results: The median age of the subjects was 49.0 years. The mean conjunctival blood flow velocity in 53 microvessels was 0.786 ± 0.468 mm/s. The median conjunctival microvascular diameter was 7.06 μm (interquartile range 5.84 to 9.23 μm). The conjunctival microvascular diameter and blood flow velocity were not significantly correlated (Spearman’s p = 0.177), and the subjects’ age and conjunctival microvascular blood flow velocity were also not correlated (Spearman’s p = 0.669). Conclusions In this study, the blood flow velocity in the bulbar conjunctival microvessels could be measured easily by means of image analysis using a slit-lamp microscope equipped with an ultra-high-speed camera with a zoom lens.

Purpose: To analyze trends in corneal transplantation surgery and determine the number of domestic and imported corneal grafts used in South Korea.Method: The total number of keratoplasties and number of each individual surgical procedure conducted in 2010 and 2020 were identified using Health Insurance Review and Assessment Service data. The number of keratoplasties using domestic corneas in 2010 and 2020 was determined from the annual report of the Korean Network for Organ Sharing (KONOS). The number of keratoplasties using imported corneas was calculated by subtracting the number of keratoplasties using domestic corneas from the total number of keratoplasties. Results: In 2010, 802 keratoplasties were performed in Korea, of which 299 (37.3%) used imported corneas; 715 (89.2%) were penetrating keratoplasties and 87 (10.8%) were anterior lamellar keratoplasties. In 2020, 911 keratoplasties were done in Korea and 564 (61.9%) used imported corneas; 541 (59.4%) were penetrating keratoplasties, 60 (6.6%) were anterior lamellar keratoplasties, and 310 (34.0%) were endothelial keratoplasties. From 2010 to 2020, the number of penetrating keratoplasties in Korea decreased, while the numbers of endothelial keratoplasties and keratoplasties using imported corneas increased. Conclusions There was a 30% decrease in the number of penetrating keratoplasties from 2010 to 2020, and a 30% increase in the numbers of endothelial keratoplasties and keratoplasties using imported corneas. The proportions of endothelial keratoplasties and imported corneas have increased steadily in Korea over the last 10 years.

Purpose: To report a case of a successful secondary Descemet membrane endothelial keratoplasty in failed penetrating keratoplasty. Case summary: A 46-year-old male with keratoconus in both of his eyes underwent penetrating keratoplasty in his right eye 30 years ago and in his left eye 14 years ago. From one and a half year ago, the patient’s visual acuity decreased in his left eye due to graft failure. For treatment, secondary Descemet membrane endothelial keratoplasty was performed. Partial detachment of Descemet membrane was observed at 13 days after the operation, and an additional air injection was performed. At 8 months after the operation, the patient’s uncorrected visual acuity improved to 0.5 and the cornea maintained its clearance without rejection. Conclusions Secondary Descemet membrane endothelial keratoplasty was successfully performed in a patient with failed penetrating keratoplasty.

Purpose: To report a case of secondary Descemet membrane endothelial keratoplasty (DMEK) for graft failure after primary DMEK.Case summary: A 47-year-old female underwent primary DMEK in her left eye with a diagnosis of Fuchs’ endothelial dystrophy. At 6 weeks later, corneal stromal edema with epithelial and subepithelial bullae was first observed. From that point on, the condition of the cornea and the visual acuity continued to degrade. After 7 months, a second DMEK procedure (i.e., a repeat DMEK) for graft failure was performed successfully without any complications. Since the second procedure, the cornea has been clear, and the best-corrected visual acuity has remained at 0.6 for 8 months. Conclusions To manage graft failure after primary DMEK, we performed a second DMEK procedure. The removal of the previous graft was easy, and there were no complications. Thus, repeat DMEK may be a feasible procedure.