Purpose: To evaluate and compare the clinical efficacy of matrix metalloproteinase-9 (MMP-9) immunoassay and tear osmolarity measurement in diagnosing dry eye severity. Methods: Dry eye disease (DED) patients underwent diagnostic tests including MMP-9 assay, tear osmolarity measurement, fluorescein tear breakup time, ocular surface staining, anesthetized Schirmer test, Ocular Surface Disease Index questionnaire, and slit-lamp examination. The dry eye parameters were compared according to positive MMP-9 status and increased tear osmolarity. The correlation between dry eye profiles and MMP-9 positivity and high tear osmolarity was also analyzed. Results: Those who tested positive in MMP-9 immunoassay had significantly higher corneal fluorescein staining score and worse DED severity than those who tested negative. The intensity of MMP-9 positivity showed positive correlation with the corneal staining score and DED severity. However, DED patients with high tear osmolarity above 308 mOsm/L did not show significantly different dry eye signs and symptoms compared to those with lower tear osmolarity values. Tear osmolarity was associated with ocular surface staining score in severe DED patients. Conclusions MMP-9 positivity was associated with ocular surface staining and worse dry eye severity. Therefore, it may be used as a useful indicator of disease severity in conjunction to other diagnostic tests.

Purpose: This study analyzed the microorganisms identified in donor corneas and their clinical significance. Methods: The medical records of 94 patients (114 eyes) who underwent keratoplasty and microbiological tests of the donor corneas from October 2008 to December 2020 at our hospital were reviewed retrospectively. During keratoplasty, we conducted microbiological tests of the corneoscleral rim of the donor cornea and preserving solution Optisol™-GS (Bausch & Lomb, Rochester, NY, USA), and examined the antibiotic susceptibility of bacterial isolates from the cultures. Results: Some isolates of domestic donor corneas revealed bacteria, but none of the imported corneas did. Gram-negative bacilli were detected from the corneoscleral rim in three eyes (2.6%): two cases of Acinetobacter baumannii/haemolyticus and one case of Pseudomonas aeruginosa. In one case (0.9%), Acinetobacter baumannii/haemolyticus was identified from preserving solution, with no bacteria found in the corneoscleral rim. Antibiotic susceptibility tests showed multi-drug resistance, except to colistin. In all cases where bacteria were detected, there was no keratitis or endophthalmitis after corneal transplantation. Conclusions Although rare, bacteria can be identified from donor corneas or the preserving solution used in corneal transplantation. Therefore, caution is needed in all processes dealing with donor corneas. Empirical antibiotics that have sufficient antimicrobial activity to suppress multi-drug resistant bacteria should be selected in corneal transplantation.

Background/Aims: Renal ischemia followed by reperfusion (I/R) is a leading cause of acute kidney injury (AKI), which is closely associated with high morbidity and mortality. Studies have shown that induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) exert powerful therapeutic effects in renal ischemia. However, the efficacy of iMSC-derived exosomes (iExo) on I/R injuries remains largely unknown. Methods: Human iPSCs were differentiated into iMSCs using a modified one-step method. Ultrafiltration, combined with purification, was used to isolate iExo from iMSCs. iExo was administered following I/R injury in a mouse model. The effect of iExo on I/R injury was assessed through changes in renal function, histology, and expression of oxidative stress, inflammation, and apoptosis markers. Further, we evaluated its association with the extracellular signal-regulated kinase (ERK) 1/2 signaling pathway. Results: Mice subjected to I/R injury exhibited typical AKI patterns; serum creatinine level, tubular necrosis, apoptosis, inflammatory cytokine production, and oxidative stress were markedly increased compared to sham mice. However, treatment with iExo attenuated these changes, significantly improving renal function and tissue damage, similar to the renoprotective effects of iMSCs on I/R injury. Significant induction of activated ERK 1/2 signaling molecules was observed in mice treated with iExo compared to those in the I/R injury group. Conclusions The present study demonstrates that iExo administration ameliorated renal damage following I/R, suggesting that iMSC-derived exosomes may provide a novel therapeutic approach for AKI treatment.

Purpose: To derive the optimized intraocular lens (IOL) constants from automated and manifest refraction after cataract surgery in Korean patients, and to evaluate whether there is a difference in optimized IOL constants according to the refraction method. Methods: This retrospective multicenter cohort study enrolled 4,103 eyes of 4,103 patients who underwent phacoemulsification and in-the-bag IOL implantation at 18 institutes. Optimized IOL constants for the SRK/T, Holladay, Hoffer Q, and Haigis formulas were calculated via autorefraction or manifest refraction of samples using the same biometry and IOL. The IOL constants derived from autorefraction and manifest refraction were compared. Results: Of the 4,103 eyes, the majority (62.9%) were measured with an IOLMaster 500 followed by an IOLMaster 700 (15.2%). A total of 33 types of IOLs were used, and the Tecnis ZCB00 was the most frequently used (53.0%). There was no statistically significant difference in IOL constants derived from autorefraction and manifest refraction when IOL constants were optimized with a large number of study subjects. On the other hand, optimized IOL constants derived from autorefraction were significantly smaller than those from manifest refraction when the number of subjects was small. Conclusions It became possible to use the IOL constants optimized from Koreans to calculate the IOL power. However, if the IOL constant is optimized using autorefraction in a small sample group, the IOL constant tends to be small, which may lead to refractive error after surgery.

Purpose: We analyzed the clinical efficacy, retention rates, and complications after inserting two types of silicone plugs in dry eye patients. Methods: The medical records of 73 patients (133 eyes) whose lacrimal puncta were occluded with the SuperEagle Punctum Plug™ (EagleVision, Denville, NJ, USA) or the Parasol Punctum Plug™ (Beaver-Visitec International, Inc. Waltham, MA, USA) were analyzed. Conventional indices for dry eye disease and tear meniscus height (TMH) using optical coherence tomography were used to determine the clinical efficacy. The overall retention rates and complications were investigated and those of each plug were compared between the two groups during the first 6 months after insertion. Results: The average age was 52.52 ± 13.66 years (13-82 years). Group A included 79 eyes and group B included 54 eyes. TMH tended to increase after 6 months regardless of plug loss or removal due to complications. Schirmer Ⅰ test value differences before and 6 months after plug insertion were positively correlated with the TMH differences in study subjects (p = 0.007). Plug loss was the most frequent complication in both groups. The retention rate of the Parasol plug was higher than the SuperEagle plug (44.4% and 24.1% respectively) (p = 0.012) and the retention rate of medium-sized plugs was higher than small-sized plugs (p = 0.027). Also, the plug retention rate decreased with age at 6 months (p = 0.032). Conclusions Punctal occlusion with a silicone punctal plug was effective, regardless of the plug type or complication. The retention rate of the Parasol plug was higher than the SuperEagle plug.

Purpose: To report a case of episcleral capillary hemangioma.Case summary: A 17-year-old woman with a left conjunctival mass since the age of 4 years visited our clinic with lesion growth that began 4 months prior. At the initial visit, the patient presented with a subconjunctival hemangiomatous mass of 3.5 × 4.5 mm in size and firmly adhered to the underlying sclera, with a feeding vessel on the temporal side of the left eye. Excisional biopsy of the mass and amniotic membrane transplantation were performed. The biopsy showed many enlarged, congested blood vessels involving subconjunctival and episcleral tissue, consistent with capillary hemangioma, as confirmed by immunohistochemical staining. There was no evidence of other hemangiomatous lesions in the eye or other areas of the body. To date, the patient has been without hemangioma recurrence for 1 year. Conclusions We noted a solitary episcleral capillary hemangioma and successfully treated the lesion.

Purpose: We report the clinical characteristics and the primary underlying diseases of patients at high risk for failure of penetrating keratoplasty (PKP) in Korea. Methods: Patients at high risk of PKP failure among those who visited the ophthalmological clinics of tertiary care hospitals in Korea from April 2019 to April 2020 and who were indicated for PKP were retrospectively enrolled. We epidemiologically investigated 119 eyes of 104 patients via medical chart review. Results: Herpes simplex virus (HSV) keratitis was the most common primary underlying disease (26.1%). The most common primary cause of poor bilateral visual acuity was Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) (41.7%) followed by chemical burns (19.4%). Of the 119 eyes, 40.3% had a history of previous PKP and 20.2% had undergone three or more PKP. The average number of prior PKPs was 1.02 ± 1.46. Corneal neovascularization and corneal opacity were reported in 82.4 and 92.4% of cases, respectively. As the severity of these conditions increased, the eye distributions became larger. Of all patients, 47.9 and 31.9%, respectively, received the highest corneal neovascularization and corneal opacity scores. Conclusions Our study of patients at high risk of PKP failure improves our understanding of the relevant clinical characteristics and primary underlying diseases. Such patients require careful observation and aggressive treatment. Possible alternatives to PKP should be considered if PKP consistently fails. This study will aid clinicians in deciding whether to proceed to surgery if a poor postoperative prognosis is predictable.

Purpose: We analyzed the clinical efficacy, retention rates, and complications after inserting two types of silicone plugs in dry eye patients. Methods: The medical records of 73 patients (133 eyes) whose lacrimal puncta were occluded with the SuperEagle Punctum Plug™ (EagleVision, Denville, NJ, USA) or the Parasol Punctum Plug™ (Beaver-Visitec International, Inc. Waltham, MA, USA) were analyzed. Conventional indices for dry eye disease and tear meniscus height (TMH) using optical coherence tomography were used to determine the clinical efficacy. The overall retention rates and complications were investigated and those of each plug were compared between the two groups during the first 6 months after insertion. Results: The average age was 52.52 ± 13.66 years (13-82 years). Group A included 79 eyes and group B included 54 eyes. TMH tended to increase after 6 months regardless of plug loss or removal due to complications. Schirmer Ⅰ test value differences before and 6 months after plug insertion were positively correlated with the TMH differences in study subjects (p = 0.007). Plug loss was the most frequent complication in both groups. The retention rate of the Parasol plug was higher than the SuperEagle plug (44.4% and 24.1% respectively) (p = 0.012) and the retention rate of medium-sized plugs was higher than small-sized plugs (p = 0.027). Also, the plug retention rate decreased with age at 6 months (p = 0.032). Conclusions Punctal occlusion with a silicone punctal plug was effective, regardless of the plug type or complication. The retention rate of the Parasol plug was higher than the SuperEagle plug.

Background/Aims: Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy. Methods: CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography–mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells. Results: The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury. Conclusions CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability

Background/Aims: Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy. Methods: CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography–mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells. Results: The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury. Conclusions CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability