Evaluation of the determinants for improved pluripotency induction and maintenance by engineered SOX17.

An engineered SOX17 variant with point mutations within its DNA binding domain termed SOX17FNV is a more potent pluripotency inducer than SOX2, yet the underlying mechanism remains unclear. Although wild-type SOX17 was incapable of inducing pluripotency, SOX17FNV outperformed SOX2 in mouse and human pluripotency reprogramming. In embryonic stem cells, SOX17FNV could replace SOX2 to maintain pluripotency despite considerable sequence differences and upregulated genes expressed in cleavage-stage embryos. Mechanistically, SOX17FNV co-bound OCT4 more cooperatively than SOX2 in the context of the canonical SoxOct DNA element. SOX2, SOX17, and SOX17FNV were all able to bind nucleosome core particles in vitro, which is a prerequisite for pioneer transcription factors. Experiments using purified proteins and in cellular contexts showed that SOX17 variants phase-separated more efficiently than SOX2, suggesting an enhanced ability to self-organise. Systematic deletion analyses showed that the N-terminus of SOX17FNV was dispensable for its reprogramming activity. However, the C-terminus encodes essential domains indicating multivalent interactions that drive transactivation and reprogramming. We defined a minimal SOX17FNV (miniSOX) that can support reprogramming with high activity, reducing the payload of reprogramming cassettes. This study uncovers the mechanisms behind SOX17FNV-induced pluripotency and establishes engineered SOX factors as powerful cell engineering tools.

MXene Supported Surface Plasmon Polaritons for Optical Microfiber Ammonia Sensing.

The properties of surface plasmons are notoriously dependent on the supporting materials system. However, new capabilities cannot be obtained until the technique of surface plasmon enabled by advanced two-dimensional materials is well understood. Herein, we present the experimental demonstration of surface plasmon polaritons (SPPs) supported by single-layered MXene flakes (Ti3C2Tx) coating on an optical microfiber and its application as an ammonia gas sensor. Enabled by its high controllability of chemical composition, unique atomistically thin layered structure, and metallic-level conductivity, MXene is capable of supporting not only plasmon resonances across a wide range of wavelengths but also a selective sensing mechanism through frequency modulation. Theoretical modeling and optics experiments reveal that, upon adsorbing ammonia molecules, the free electron motion at the interface between the SiO2 microfiber and the MXene coating is modulated (i.e., the modulation of the SPPs under applied light), thus inducing a variation in the evanescent field. Consequently, a wavelength shift is produced, effectively realizing a selective and highly sensitive ammonia sensor with a 100 ppm detection limit. The MXene supported SPPs open a promising path for the application of advanced optical techniques toward gas and chemical analysis.

Molecular Structure Engineering of Isomeric Additives for Long Lifetime Zn Anodes.

Modulating the solvation structure of hydrated zinc ions using organic additives stands as a pragmatic approach to suppress dendrite formation and corrosion on zinc metal anodes (ZMAs), thereby enhancing the rechargeability of aqueous Zn-ion batteries. However, fundamental screening principles for organic additives with diverse molecular structures remain elusive, especially for isomers with the same molecular formula. This study delves into the impact of three isomeric hexagonal alcohols (mannitol, sorbitol, and galactitol) as additives in adjusting Zn2+ solvation structural behaviors within ZnSO4 baseline electrolytes. Electrical measurements and molecular simulations reveal the specific molecular structure of mannitol, which features interweaving electron clouds between adjacent hydroxyl groups, achieving a high local electron cloud density. This phenomenon significantly enhances desolvation abilities, thus establishing a more stable anode/electrolyte interface chemistry. Even at 5 mA cm-2 for 2.5 mAh cm-2 capacity, Zn||Zn symmetric cells with mannitol-regulated electrolyte display an impressive 1170 h lifespan, far exceeding those with other isomer additives and is nearly tenfold longer than that with a pure ZnSO4 electrolyte (120 h). Rather than strictly adhering to focusing on chemical composition, this study with emphasis on optimizing molecular structure offers a promising untapped dimension to screen more efficient additives to enhance the reversibility of ZMAs.

Directed Evolution of an Enhanced POU Reprogramming Factor for Cell Fate Engineering.

Transcription factor-driven cell fate engineering in pluripotency induction, transdifferentiation, and forward reprogramming requires efficiency, speed, and maturity for widespread adoption and clinical translation. Here, we used Oct4, Sox2, Klf4, and c-Myc driven pluripotency reprogramming to evaluate methods for enhancing and tailoring cell fate transitions, through directed evolution with iterative screening of pooled mutant libraries and phenotypic selection. We identified an artificially evolved and enhanced POU factor (ePOU) that substantially outperforms wild-type Oct4 in terms of reprogramming speed and efficiency. In contrast to Oct4, not only can ePOU induce pluripotency with Sox2 alone, but it can also do so in the absence of Sox2 in a three-factor ePOU/Klf4/c-Myc cocktail. Biochemical assays combined with genome-wide analyses showed that ePOU possesses a new preference to dimerize on palindromic DNA elements. Yet, the moderate capacity of Oct4 to function as a pioneer factor, its preference to bind octamer DNA and its capability to dimerize with Sox2 and Sox17 proteins remain unchanged in ePOU. Compared with Oct4, ePOU is thermodynamically stabilized and persists longer in reprogramming cells. In consequence, ePOU: 1) differentially activates several genes hitherto not implicated in reprogramming, 2) reveals an unappreciated role of thyrotropin-releasing hormone signaling, and 3) binds a distinct class of retrotransposons. Collectively, these features enable ePOU to accelerate the establishment of the pluripotency network. This demonstrates that the phenotypic selection of novel factor variants from mammalian cells with desired properties is key to advancing cell fate conversions with artificially evolved biomolecules.

The Retrograde Basilic Approach for Balloon-Assisted Maturation of Brachiocephalic Arteriovenous Fistulas.

PURPOSE: To assess the feasibility and outcomes of an approach utilizing transbasilic access for balloon-assisted maturation (BAM) of brachiocephalic arteriovenous fistulas (BCAVFs). MATERIALS AND METHODS: This retrospective analysis comprised 28 patients (mean age, 63 years ± 10.8) who underwent endovascular treatment of their immature BCAVFs via a basilic approach from December 2016 to December 2018. The mean age of the BCAVFs was 3.3 months ± 1.4 at the time of BAM. Other demographic data, vascular access characteristics, procedural data, technical and clinical success rates, and adverse events were also evaluated. RESULTS: All patients had inflow juxta-anastomotic stenoses, with 4 patients (14%) having concomitant outflow tract stenoses and 1 patient (4%) having a short-segment occlusion at the stenotic juxta-anastomotic segment. Technical success was achieved in 27 patients (96%). The mean diameter of the largest balloon used was 5.7 mm ± 0.6. Clinical success was achieved in 22 patients (79%), with 6 patients (21%) requiring a subsequent additional intervention before successful cannulation. No perioperative adverse events were observed. CONCLUSIONS: The retrograde basilic approach is feasible, safe, and effective for BAM of BCAVFs.

Validation of a More Reliable Method of Eye Drop Self-Administration.

SIGNIFICANCE: We propose an alternative method for eye drop self-administration. Similar IOP reductions were found with this method compared with clinician instillation. The alternative method of self-administration potentially benefits patients who have trouble successfully instilling drops. PURPOSE: The purpose of this study was to validate the efficacy of an alternative method of drop instillation. METHODS: This study is a randomized controlled crossover clinical trial. Thirty participants were recruited. A drop of 0.5% timolol maleate was instilled into subject's eye on two separate visits. On one visit, eye drop instillation was by a trained clinician, and on the other, self-instillation using an alternative method was used. The order was randomly chosen. Intraocular pressure was measured before drop instillation and 2 hours after drop instillation. The investigator was masked during measurement, and an observer recorded the IOP measurements. RESULTS: Mean ± SD IOP measurement before 0.5% timolol maleate instillation measured 13.89 ± 2.29 mmHg. An average reduction 3.75 ± 2.36 mmHg was found with clinician administration, and an average reduction of 3.32 ± 2.31 mmHg was recorded with the new method. No significance was found in IOP reduction between two groups P < .45. Percent reduction was 25.17 ± 16.21% and 24.38 ± 16.31% in clinician instillation and alternative instillation method group, respectively. No significant difference was found. This percentage reduction was similar to previously reported studies. No reported cases of eye infection or irritation were found in any case, within a 3-month follow-up period. CONCLUSIONS: We have proposed a more reliable method for instillation that provides a larger area for instillation and lessen the risk of contamination and patient's fear for eye drops. Similar efficacy was found compared with that of having a clinician directly administer the drop. This alternative method could potentially benefit patients who require topical eye drop therapy and result in increased compliance.

Light Emitting Diode Phototherapy for Skin Aging.

Skin aging is associated with changes that include atrophy, pigmentation, decreased ability for wound healing, and rhytides. Recently, there has been growing research interest and consumer demand for minimally invasive cosmetic procedures involving light and energy-based devices, particularly for facial skin rejuvenation. Light emitting diode (LED) phototherapy is a promising treatment modality for photorejuvenation as it is safe, noninvasive, accessible, and can be easily combined with other treatment options. LED irradiation alters intrinsic cellular activity via absorption by chromophores located in the skin and may result in desirable photorejuvenation effects. In this review, we discuss the physiologic process of cutaneous aging, how visible light phototherapy with LEDs may be used to treat aging skin, and the importance of photoprotection. J Drugs Dermatol. 2020;19(4):359-364. doi:10.36849/JDD.2020.4711.

In Situ Electrochemical and PM-IRRAS Studies of Colicin E1 Ion Channels in the Floating Bilayer Lipid Membrane.

Colicin E1 is a channel-forming bacteriocin produced by certain Escherichia coli cells in an effort to reduce competition from other bacterial strains. The colicin E1 channel domain was incorporated into a 1,2-diphytanoyl- sn-glycero-3-phosphocholine floating bilayer situated on a 1-thio-?-d-glucose-modified gold (111) surface. The electrochemical properties of the colicin E1 channel in the floating bilayer were measured by electrochemical impedance spectroscopy; the configuration and orientation of colicin E1 in the bilayer were determined by polarization-modulation-infrared-reflection absorption spectroscopy. The EIS and IR results indicate that colicin E1 adopts a closed-channel state at the positive transmembrane potential, leading to high membrane resistance and a large tilt angle of ?-helices. When the transmembrane potential becomes negative, colicin E1 begins to insert into the lipid bilayer, corresponding to low membrane resistance and a low tilt angle of ?-helices. The insertion of colicin E1 into the lipid bilayer is driven by the negative transmembrane potential, and the ion-channel open and closed states are potential reversible. The data in this report provide new insights into the voltage-gated mechanism of colicin E1 ion channels in phospholipid bilayers and illustrate that the floating bilayer lipid membrane at the metal electrode surface is a robust platform to study membrane-active proteins and peptides in a quasi-natural environment.

An ultra-sensitive and ratiometric fluorescent probe based on the DTBET process for Hg2+ detection and imaging applications.

In this article, we present an ultra-sensitive and ratiometric fluorescent probe (TR-Hg) for Hg2+ detection based on the mechanism of aggregation induced emission (AIE) and dark through-bond energy transfer (DTBET). The probe was constructed using tetraphenylethene as the dark donor and rhodamine B thiolactone as the acceptor. By exploiting the advantages of DTBET, which eliminates emission leakage from dark donors and provides nearly 100% energy transfer efficiency, TR-Hg exhibits more than a 30 000-fold fluorescence ratio enhancement after reacting with Hg2+. TR-Hg demostrates (i) a detection limit of 43 pM, which is the lowest among the reported ratiometric Hg2+ probes, (ii) excellent selectivity, fast response-time (<10 s) and a wide pH application range, (iii) strong applicability for paper-based colorimetric assay, where readout can be performed by the naked eye, and (iv) fluorescent imaging of Hg2+ in onion epidermal tissues, indicating its potential use in living organisms.

Liquid-core waveguide TCSPC sensor for high-accuracy fluorescence lifetime analysis.

Liquid-core waveguide (LCW) has many advantages such as the elimination of optical artifacts typically exhibited in systems employing lenses and filters. However, due to the effect of temporal dispersion, LCWs are typically employed in steady-state fluorescence detection microsystems rather than in fluorescence lifetime measurement (FLM) systems. In this paper, we present a compact liquid-core waveguide time-correlated single-photon counting (LCW-TCSPC) sensor for FLM. The propagation of excitation within the LCW is analyzed both analytically and in simulations, with results in agreement with experimental characterization. Results reveal an optimal region within the LCW for highly accurate FLM. The proposed prototype achieves excellent excitation rejection and low temporal dispersion as a result of optimization of the propagation length of the excitation within the LCW. The prototype achieves a detection limit of 5 nM for Coumarin 6 in dimethyl sulfoxide with < 3% lifetime error. The techniques proposed for analyzing the LCW for TCSPC based FLM and prototype demonstration pave the way for developing high-performance fluorescence lifetime measurement for microfluidics and point-of-care applications. Graphical abstract A compact liquid-core waveguide time-correlated single-photon counting (LCW-TCSPC) sensor for fluorescence lifetime measurement (FLM) is presented. Results reveal an optimal propagation length region within the LCW for highly accurate FLM. The prototype achieves a detection limit of 5 nM for Coumarin 6 in dimethyl sulfoxide with < 3% lifetime error.

A Low-Cost Time-Correlated Single Photon Counting Portable DNA Analyzer.

Photon-counting analysis of nucleic acids plays a key role in many diagnostics applications for its accurate and non-invasive nature. However, conventional photon-counting instrumentations are bulky and expensive due to the use of conventional optics and a lack of optimization of electronics. In this paper, we present a portable, low-cost time-correlated single photon-counting (TCSPC) analysis system for DNA detection. Both optical and electronic subsystems are carefully designed to provide effective emission filtering and size reduction, delivering good DNA detection and fluorescence lifetime extraction performance. DNA detection has been verified by fluorescence lifetime measurements of a V-carbazole conjugated fluorophore lifetime bioassay. The time-to-digital module of the proposed TCSPC system achieves a full width at half maximum (FWHM) timing resolution from 121 to 145 ps and a differential non-linearity (DNL) between -8.5% and +9.7% of the least significant bit (LSB) within the 500 ns full-scale range (FSR). With a detection limit of 6.25 nM and a dynamic range of 6.8 ns, the proposed TCSPC system demonstrates the enabling technology for rapid, point-of-care DNA diagnostics.

An Omni-Healable and Highly Sensitive Capacitive Pressure Sensor with Microarray Structure.

Capacitive pressure sensors with high flexibility, sensitivity, and excellent healable properties are desirable for a wide variety of applications, such as e-skin. However, implementing these characteristics onto a device presently remains a great challenge. In this work, a flexible pressure sensor with high sensitivity and strong healable properties has been developed based on healable polyurethane (HPU), silver nanowires and graphene. The HPU-based microstructured capacitive pressure sensor exhibited a high sensitivity of 1.9 kPa-1 (<3 kPa), a fast response time (<100 ms), low detection limit (10 Pa), and long-term durability (1000 cycles). Touch-finger and vocal-cord vibration detection have been demonstrated and exhibit a high sensitivity to both static and dynamic pressure. More notably, the entire pressure sensor including the dielectric layer and electrodes is omni-healable after complete separation. The prototype has experimentally shown tremendous potential for wearable, healable applications, such as healthcare monitoring and human-machine interfaces.

The efficacy of Viscocanalostomies and combined phacoemulsification with Viscocanalostomies in the treatment of patients with glaucoma: a non-randomised observational study.

BACKGROUND: To evaluate the outcomes of Viscocanalostomy (VC) and Phacoviscocanalostomy (PV) in controlling primary and secondary glaucoma in a large cohort of patients from a single eye unit and performed by a single surgeon. METHODS: This non-randomised, retrospective study was conducted on 620 eyes of 458 patients. All patients who had either viscocanalostomy (VC) or combined phacoemulsification and viscocanalostomy (PV) over a three-year period were included. Intraocular pressures (IOP), number of anti-glaucoma medications used, and any complications were recorded over a 3-year follow up period. Paired T-Test was used to compare preoperative and post-operative IOP at specified time points. Kaplan-Meier survival models were used to determine success rates over the study period. RESULTS: Six hundred twenty procedures were performed during the 3-year study period, of which 427 were PV and 193 VC. The mean follow-up was 31.8 months. Overall complete success (IOP ≤ 21 mmHg, without medication) at 3 years was achieved in 65.7% of patients, with qualified success (IOP ≤21 mmHg with or without medication) achieved in 96.0%. Subgroup analysis showed complete success rate of 76.0% for PV and 63.1% for VC (p = 0.005), with qualified success 95.9% for PV and 94.0% for VC (p = 0.668). Mean pre-operative IOP (mmHg) for all procedures was 23.02 ± 5.6, with PV and VC subgroups at 22.54 ± 5.10 and 24.06 ± 6.45. Post-operatively IOP at month 12 and 36 was 14.74 ± 3.57 and 14.40 ± 3.17 respectively for all procedures, 14.62 ± 3.26 and 14.44 ± 3.10 for PV, and 15.03 ± 4.18 and 14.31 ± 3.33 for VC. Across all procedures, pre-operatively an average of 3.05 ± 0.96 anti-glaucoma medications were used. This reduced to 0.13 ± 0.39 in 12 months and 0.38 + 0.71 by 36 months. Sixty-five cases had complications due to trabeculo-Descemet window perforation during viscocanalostomy with 7 cases developing complications from the cataract element. In the 12.9% of patients who had complications there were no differences of IOP noted at 3 years. CONCLUSION: VC and PV have good IOP lowering capacity and are both effective at sustaining a reduction in IOP at 3 years. PV achieved a higher success rate without medication. The low complication profile with reduced post-operative care means these procedures may be a preferred option for early surgical intervention.

Light-emitting diodes in dermatology: A systematic review of randomized controlled trials.

OBJECTIVE: In dermatology, patient and physician adoption of light-emitting diode (LED) medical technology continues to grow as research indicates that LEDs may be used to treat skin conditions. The goal of this systematic review is to critically analyze published randomized controlled trials (RCTs) and provide evidence-based recommendations on the therapeutic uses of LEDs in dermatology based on published efficacy and safety data. METHODS: A systematic review of the published literature on the use of LED treatments for skin conditions was performed on September 13th 2017. RESULTS: Thirty-one original RCTs were suitable for review. CONCLUSIONS: LEDs represent an emerging modality to alter skin biology and change the paradigm of managing skin conditions. Acne vulgaris, herpes simplex and zoster, and acute wound healing received grade of recommendation B. Other skin conditions received grade of recommendation C or D. Limitations of some studies include small patient sample sizes (n < 20), absent blinding, no sham placebo, and varied treatment parameters. Due to few incidences of adverse events, affordability, and encouraging clinical results, we recommend that physicians use LEDs in clinical practice and researchers continue to explore the use of LEDs to treat skin conditions. Lasers Surg. Med. 9999:1-16, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Determination of the Optimal Sensing Temperature in Pt/Ta2O5/MoO3 Schottky Contacted Nanobelt Straddling Heterojunction.

Nanostructured Schottky barrier gas sensors have emerged as novel semiconductor devices with large surface areas and unique electronic characteristics. Although it is widely known that operating these gas sensors requires heating to an optimal temperature for the highest sensitivity, the fundamental mechanism that governs the temperature-dependent sensitivity has yet been well understood. In this work, we present new evidence to support that thermionic field emission (TFE) is the dominant transport mechanism for Schottky contacted nanostructured heterojunction gas sensors at their optimal sensing temperature. Through the fabrication and characterization of Pt/MoO3 Schottky contacts, and Pt/Ta2O5/MoO3 heterojunctions, we found a previously unreported connection between TFE transport and optimal gas sensing temperature. This connection enables the description of Schottky barrier gas sensing performance using transport theory, which is a major step towards systematic engineering of gas sensors with nanostructured high-k oxide layers.

Feasibility of clinical detection of cervical dysplasia using angle-resolved low coherence interferometry measurements of depth-resolved nuclear morphology.

This study sought to establish the feasibility of using in situ depth-resolved nuclear morphology measurements for detection of cervical dysplasia. Forty enrolled patients received routine cervical colposcopy with angle-resolved low coherence interferometry (a/LCI) measurements of nuclear morphology. a/LCI scans from 63 tissue sites were compared to histopathological analysis of co-registered biopsy specimens which were classified as benign, low-grade squamous intraepithelial lesion (LSIL), or high-grade squamous intraepithelial lesion (HSIL). Results were dichotomized as dysplastic (LSIL/HSIL) versus non-dysplastic and HSIL versus LSIL/benign to determine both accuracy and potential clinical utility of a/LCI nuclear morphology measurements. Analysis of a/LCI data was conducted using both traditional Mie theory based processing and a new hybrid algorithm that provides improved processing speed to ascertain the feasibility of real-time measurements. Analysis of depth-resolved nuclear morphology data revealed a/LCI was able to detect a significant increase in the nuclear diameter at the depth bin containing the basal layer of the epithelium for dysplastic versus non-dysplastic and HSIL versus LSIL/Benign biopsy sites (both p < 0.001). Both processing techniques resulted in high sensitivity and specificity (>0.80) in identifying dysplastic biopsies and HSIL. The hybrid algorithm demonstrated a threefold decrease in processing time at a slight cost in classification accuracy. The results demonstrate the feasibility of using a/LCI as an adjunctive clinical tool for detecting cervical dysplasia and guiding the identification of optimal biopsy sites. The faster speed from the hybrid algorithm offers a promising approach for real-time clinical analysis.

Scanning system for angle-resolved low-coherence interferometry.

Angle-resolved low-coherence interferometry (a/LCI) detects precancer by enabling depth-resolved measurements of nuclear morphology in vivo. A significant limitation of a/LCI is the point-probe nature of the method, sampling <0.5 mm2 before probe relocation is necessary. In this work, we demonstrate a scanning method capable of assessing an area >100 mm2 without repositioning. By utilizing a reflection-only three-optic rotator prism and a two-axis scanning mirror, we demonstrate radial scans of a sample with a linear range of 12 mm and a full rotational range of 180°. Use of this design will improve the diagnostic utility of a/LCI for wide-area screening of tissue health.

Midterm Outcomes From a Pilot Study of Percutaneous Deep Vein Arterialization for the Treatment of No-Option Critical Limb Ischemia.

PURPOSE: To report the initial clinical experience with percutaneous deep vein arterialization (PDVA) to treat critical limb ischemia (CLI) via the creation of an arteriovenous fistula. METHODS: Seven patients (median age 85 years; 5 women) with CLI and no traditional endovascular or surgical revascularization options (no-option CLI) were recruited in a pilot study to determine the safety of PDVA. All patients were diabetic; 4 had Rutherford category 6 ischemia. Six were classified at high risk of amputation based on the Society for Vascular Surgery WIfI (wound, ischemia, and foot infection) classification. The primary safety endpoints were major adverse limb events and major adverse coronary events through 30 days and serious adverse events through 6 months. Secondary objectives included clinical efficacy based on outcome measures including thermal measurement, transcutaneous partial pressure of oxygen (TcPO2), clinical improvement at 6 months, and wound healing. RESULTS: The primary safety endpoints were achieved in 100% of patients, with no deaths, above-the-ankle amputations, or major reinterventions at 30 days. The technical success rate was 100%. Two myocardial infarctions occurred within 30 days, each with minor clinical consequences. All patients demonstrated symptomatic improvement with formation of granulation tissue, resolution of rest pain, or both. Complete wound healing was achieved in 4 of 7 patients and 5 of 7 patients at 6 and 12 months, respectively, with a median healing time of 4.6 months (95% confidence interval 84-192). Median postprocedure peak TcPO2 was 61 mm Hg compared to a preprocedure level of 8 mm Hg (p=0.046). At the time of wound healing, 4 of 5 of patients achieved TcPO2 levels of >40 mm Hg. There were 2 major amputations, 1 above the knee after PDVA thrombosis and 1 below the knee for infection. Three patients died of causes unrelated to the procedure or study device at 6, 7, and 8 months, respectively. Limb salvage was 71% at 12 months. CONCLUSION: PDVA is an innovative approach for treating no-option CLI and represents an alternative option for the "desert foot," potentially avoiding major amputation. Our results demonstrate its safety and feasibility, with promising early clinical results in this small cohort.

Folded bandage contact lens retention in a patient with bilateral dry eye symptoms: a case report.

BACKGROUND: Bandage contact lenses are commonly used by ophthalmic practitioners to protect the patient's cornea. We report a case of folded bandage contact lens retained for six and a half years in the upper subtarsal space. To our knowledge, no other cases of retained bandage contact lens have previously been reported in the literature. CASE PRESENTATION: A patient was applied a pair of bandage contact lenses due to persistent ocular pain secondary to dry eye symptoms. At her subsequent visit, bandage contact lens was removed from her left eye, but none was found in the right eye. Documentation from further visit stated that the bandage contact lenses were no longer in situ. 6.5 years since the lens insertion, lid eversion revealed a 'foreign body' retained beneath her right upper eyelid, which was noted to be a folded, discoloured bandage contact lens. CONCLUSIONS: The 'upper fornix trap', where the contact lens may be retained by the upper tarsal edge, presents an anatomical hazard for contact lens users. Moreover, soft contact lenses may be more likely to retain asymptomatically and to fold onto itself compared to hard lenses. Our case report highlights the importance of performing a thorough eye examination, which includes double eversion of the upper eyelids and sweeping of the fornices with cotton buds, and maintaining clinical suspicion of contact lens retention.