Fung-Rong Hu

Purpose: To evaluate the effect of iris-claw phakic intraocular lenses (pIOLs) on anterior chamber depth (ACD) measurement by optical biometers and the potential impact of ACD errors on hypothetical intraocular lens (IOL) power selection for cataract surgery. Patients and Methods: Seventy-six eyes of 38 patients with iris-claw pIOLs (Artiflex) underwent biometry using Pentacam (Scheimpflug), Lenstar LS-900 (optical low-coherence reflectometry), and Eyestar 900 (swept-source OCT). The failure and misidentification rates of ACD measurement were recorded. Eyestar B-scans were manually reviewed and corrected when segmentation errors were identified. Hypothetical IOL power was calculated using Barrett Universal II and SRK/T formulas. Results: Pentacam successfully measured ACD in all 76 eyes. Lenstar LS-900 angd Eyestar 900 failed to provide ACD measurements in 4 eyes (5.3%) and 14 eyes (18.4%), respectively. Using a predefined threshold of > 10% deviation from the Pentacam value, inaccurate ACD measurements were identified in 30 eyes (39.5%) with Lenstar and in 17 eyes (22.4%) with Eyestar. On Eyestar, 20 eyes (26.3%) showed misidentification of the anterior pIOL surface as the anterior capsule of the crystalline lens, and 11 eyes (14.5%) were interpreted as aphakic. After manual correction, Eyestar ACD values closely matched Pentacam measurements, with a mean difference of 0.04 ± 0.03 mm. Correction of erroneous ACD measurements changed Barrett Universal II–based hypothetical IOL power selection by at least 0.50 D in 7 of 17 affected eyes (41.2%). Conclusion: In eyes with iris-claw pIOLs, automated optical biometers may misidentify ocular structures and underestimate ACD, potentially leading to clinically meaningful differences in hypothetical IOL power selection. Manual review and correction of Eyestar B-scan images restored ACD measurements to close agreement with Pentacam values. These findings highlight the importance of careful inspection of raw biometry images in such eyes, particularly when using formulas that incorporate measured ACD.

Introduction Although antifungal supplementation reduces the fungal load in the corneal storage medium, consensus is lacking on the influence of dosing and temperature. The study aims to evaluate the impact of eye bank warming protocol and timing of antifungal supplements on efficacy in Optisol-GS and tissue. Methods Corneoscleral rims contaminated with Candida albicans (C. albicans) were incubated in Optisol-GS, either without antifungal agents or with the addition of amphotericin B or voriconazole at various concentrations (2 ×, 5 ×, 10 ×, and 20 × MIC), at different time points, and under various preservation temperatures (2–8 °C versus 2 h-room temperature exposure). Antifungal efficacy was evaluated by counting viable yeast colonies cultured from Optisol-GS samples. Tissue sterility was determined through direct tissue culture and histological examination of the contaminated rims after a 14-day incubation period. Results Room temperature exposure did not increase colony growth at the same multiple MIC of antifungal agents. Although antifungal addition reduced C. albicans growth in a concentration-dependent manner, yeast growth was still observed in all Optisol-GS samples with a single supplementation after a 14-day incubation. Only groups with additional antifungal supplementation on either day 2 or day 6 showed a 99% or greater reduction of C. albicans growth in Optisol-GS samples and yielded negative results in direct tissue culture. Conclusions The eye bank warming protocol did not compromise antifungal efficacy. To sustain the required concentration and effectively reduce C. albicans growth in Optisol-GS and contaminated tissue, additional antifungal supplementation on either day 2 or day 6 was necessary during a 2-week preservation period.

The diagnosis of inherited retinal degeneration (IRD) is challenging owing to its phenotypic and genotypic complexity. Clinical information is important before a genetic diagnosis is made. Metabolomics studies the entire picture of bioproducts, which are determined using genetic codes and biological reactions. We demonstrated that the common diagnoses of IRD, including retinitis pigmentosa (RP), cone-rod dystrophy (CRD), Stargardt disease (STGD), and Bietti’s crystalline dystrophy (BCD), could be differentiated based on their metabolite heatmaps. Hundreds of metabolites were identified in the volcano plot compared with that of the control group in every IRD except BCD, considered as potential diagnosing markers. The phenotypes of CRD and STGD overlapped but could be differentiated by their metabolomic features with the assistance of a machine learning model with 100% accuracy. Moreover, EYS-, USH2A-associated, and other RP, sharing considerable similar characteristics in clinical findings, could also be diagnosed using the machine learning model with 85.7% accuracy. Further study would be needed to validate the results in an external dataset. By incorporating mass spectrometry and machine learning, a metabolomics-based diagnostic workflow for the clinical and molecular diagnoses of IRD was proposed in our study.

Export Background. This study aims to investigate the rationality of the allocation guidelines in a hepatitis B endemic area that uses corneas from hepatitis B donors. Methods. Under Taiwan’s current guidelines, corneas donated from hepatitis B surface antigen (HBsAg)(+) donors can be allocated to HBsAg(+) or hepatitis B surface antibody recipients. From January 1, 2015, to December 31, 2019, corneas donated to National Taiwan University Hospital were divided into HBsAg(+), HBsAg(–)/hepatitis B core antibody (anti-HBc)(+), and HBsAg(–)/anti-HBc(–) groups. Hepatitis B virus (HBV) DNA extracted from corneoscleral rims was quantified by polymerase chain reaction and correlated with donor serum HBsAg, anti-HBc, and HBV DNA. Recipients of HBV DNA(+) grafts were called back for serology and serum HBV DNA tests. Results. The corneoscleral HBV DNA of 170 corneas (113 donors) was quantified, of which 45 corneas were from 28 HBsAg(+) donors, 87 were from 57 HBsAg(–)/anti-HBc(+) donors, and 38 were from 28 HBsAg(–)/anti-HBc(–) donors, and HBV DNA was detected in 80.0%, 9.2%, and 0% of the corneoscleral rims in each group. Donor anti-HBc(+) provided the highest sensitivity (1.00) and negative predictive value (1.00) for corneoscleral HBV DNA. Twenty-eight of 40 recipients (70%) using HBV DNA(+) grafts were called back, and none developed hepatitis in follow-up periods ranging from 6 to 55.5 mo. Conclusions. Donor anti-HBc should be tested routinely with HBsAg. Allocating corneas from HBsAg(+) or anti-HBc(+) donors to HBsAg(+) or hepatitis B surface antibody recipients maximizes cornea usage from hepatitis B donors without compromising transplant safety in a hepatitis B endemic setting.

Background/aims: To evaluate the utility rate, indication, outcome, and cost of refrigeration and glycerol cryopreservation for storing anterior corneal buttons during endothelial keratoplasty for subsequent use in tectonic lamellar patch grafting.Method: Anterior corneal buttons collected after precutting or prestripping during endothelial keratoplasty from January 2014 to December 2019 were preserved using the following protocol: (1) refrigeration for up to 4 weeks at 4°Cin Optisol-GS and (2) glycerol cryopreservation for up to 2 years. The utility rate, outcome and cost of these cryopreserved anterior corneal buttons were retrospectively examined.Results: During the 6-year study period, 26 anterior corneal buttons were refrigerated and 49 were cryopreserved for extended use. The utility rates for the refrigerated and cryopreserved anterior corneal buttons were 69.2% and 73.5%, respectively. Their average preservation periods were 0.53±0.05 and 12.76±0.94 months, respectively. Noninfection-related perforation was the leading indication for using the extendedly preserved anterior corneal buttons. The average postoperative follow-up periods were 10.03±2.91 and 14.35±2.17 months for refrigerated and cryopreserved anterior corneal buttons. Secondary keratoplasty was required by 7 of 18 (38.9%) and 6 of 36 (16.7%) patients receiving refrigerated and cryopreserved anterior corneal buttons, respectively. None of our patients developed graft infection from donor tissues.Conclusion: Cryopreservation can safely extend the utility of anterior corneal buttons. This method not only reduced the wastage of the limited donor tissue but also was cost-effective.

Purpose: To determine the role of transmembrane mucins in blocking fluorescein ingress to the corneal epithelium and its deficiency in contributing to corneal fluorescein punctate staining. Methods: A dry eye model was established by extirpating lacrimal and Harderian glands in rabbits to correlate the expression of mucins with fluorescein-stained areas on the corneal button using immunofluorescence. Expression of transmembrane mucins was promoted in human corneal epithelial cells (HCECs) by culturing with the mucin-promoting medium (MPM) or diquafosol treatment. Conversely, the expression of mucins was downregulated by knockdown with short hairpin RNA. The role of mucin1 extracellular domain in fluorescein ingress was further verified by overexpression of N-terminally truncated mucin1 in HCECs. Results: In the rabbit dry eye model, the expression level of mucin1 was significantly decreased in superficial corneal epithelial cells where fluorescein punctate staining was observed. Upregulation of mucin1 and mucin16 in HCECs promoted by MPM or by diquafosol treatment impeded intracellular fluorescein ingress. Downregulation of mucin1 and mucin16 enhanced fluorescence ingress in HCECs after fluorescein staining. Overexpression of truncated mucin1 did not alter the fluorescein intensity of fluorescein-stained HCECs, supporting the notion that the ability of mucin1 to block fluorescein ingress was primarily mediated by its extracellular domain. Minimal inherent expression of mucin16 in the rabbit cornea limited the validation of its role in blocking fluorescein ingress in vivo. Conclusion: Transmembrane mucin1 blocks fluorescein ingress in the corneal epithelium, explaining how fluorescein staining is positive when the level of transmembrane mucins is disturbed in dry eyes.

This study aimed to evaluate the medical and socioeconomic impacts of IRDs using the nationwide health database and a large hospital-based cohort. This retrospective cross-sectional cohort study used data from the nationwide National Health Insurance Research Database (NHIRD). All patients with IRD from January 2012 to December 2016 were selected from the NHIRD and matched with the general population at a ratio of 1:4. All variables, including comorbidities, medications, service utilization, and medical costs, within 1 year from the date of the IRD diagnosis, were analyzed. Disability data were retrieved from the Taiwan Inherited retinal degeneration Project (TIP), a medical center-based database. A total of 4447 and 17,788 subjects from the nationwide database were included in the IRD and control groups, respectively. The Charlson comorbidity index score was higher in the IRD group (0.74:0.52, p < 0.001). Yearly visits to the ophthalmology clinic were more frequent in the IRD group (6.80:1.06, p < 0.001), particularly to tertiary medical centers (p < 0.001). The IRD group showed greater odds ratios (OR) for metabolic syndrome-related comorbidities, including hypertension (OR = 1.18, 95% confidence interval (CI) 1.10 to 1.26) and diabetes (OR = 1.32, 95% CI 1.21 to 1.45), and double the average yearly medical cost (2104.3 vs. 1084.6 USD, p < 0.001) and ten times the yearly ophthalmology cost (369.1 vs. 36.1 USD, p < 0.001). The average disability level was 54.17% for all subjects. This study revealed the large medical and socioeconomic impacts of IRD on not only patients with IRD, but also their family members and the whole society.

Inherited retinal degenerations (IRDs) are a group of phenotypically and genotypically heterogeneous disorders with substantial socioeconomic impact. In this cohort study, we tried to address the genetic characteristics and epidemiology of IRDs in Taiwan. Totally, 312 families with IRDs were identified and recruited and genetic testing was performed via probe capture-based NGS targeting 212 IRD-related genes. Statistical analysis was based on the proband of each affected family. Disease-causing genotypes were identified in 178 families (57.1%). ABCA4 variants were the most common cause of disease in this cohort (27 families, 15.2%), whereas CYP4V2 variants were the most common cause for the single phenotype—Bietti’s crystalline dystrophy (12 families, 3.8%). Some variants such as ABCA4:c.1804C>T, CYP4V2:c.802-8_810delinsGC, and EYS:c6416G>A were population-specific disease-causing hotspots. Probands affected by ABCA4, RPGR, RP1L1, and CEP290 sought medical help earlier while patients affected by EYS and CYP4V2 visited our clinic at an older age. To evaluate the representativeness of our cohort in the genetic epidemiology of IRDs in Taiwan, our demographic data were compared with that of the total IRD population in Taiwan, obtained from the National Health Insurance Research Database. This is currently the largest-scale, comprehensive study investigating the genetic characteristics and epidemiology of IRD in Taiwan. These data could help patients and caregivers to adopt precision genomic medicine and novel gene therapies in near future.