Towards detection of biomarkers in the eye using an aptamer-based graphene affinity nanobiosensor.

We present an approach to enable the sensitive and specific detection of biomarkers in undiluted tears in the eye using an aptamer-based graphene affinity nanosensor. The nanosensor is a graphene field-effect transistor, in which a nucleic acid aptamer and a biomolecule-permeable polyethylene glycol (PEG) nanolayer are immobilized on the graphene surface. The aptamer is capable of specifically recognize the target biomarker and induce a change in the carrier concentration of the graphene, which is measured to determine the biomarker concentration. The PEG nanolayer minimizes nonspecific adsorption of background molecules in the sample that would otherwise interfere with the biomarker detection. Experimental results show that tumor necrosis factor alpha (TNF-alpha), an inflammatory cytokine, can be sensitively and specifically detected in undiluted artificial tears with a limit of detection of 0.34 pM. This ability to detect and measure biomarkers in undiluted physiological fluids allows the nanosensor to be potentially used in applications where sample dilutions are not practical, such as wearable measurements of tear-borne biomarkers in the eye.

A case of sight threatening complications from topical 1% 5-fluorouracil in the treatment of ocular surface squamous neoplasia.

PURPOSE: 1% topical 5-fluorouracil (5-FU) is a treatment for ocular surface squamous neoplasia (OSSN) due to its effectiveness, low cost, and tolerable side effect profile. To our knowledge there is no reported sight-threatening corneal complication of 1% 5-FU for the treatment of OSSN. OBSERVATIONS: We report a 78 year-old man with bilateral conjunctival intraepithelial neoplasia (CIN) who developed bilateral corneoscleral ulceration and corneal perforation of the left eye after 1% 5-FU topical treatment. CONCLUSIONS AND IMPORTANCE: Our case report describes serious potential complications of 1% 5-FU, reviews possible risk factors associated with poor outcomes, and discusses our treatment approach.

Outcomes of four-point suture fixated and two-point sutureless posterior chamber IOLs combined with pars plana vitrectomy.

BACKGROUND: While each scleral fixation method has its own advantages, there is a lack of strong evidence to suggest a superior technique. Advances in cataract surgery expand patient eligibility for successful cataract extraction, benefitting a growing population of pseudophakic patients. However, implantation of secondary intraocular lens (IOL) with compromised anterior or posterior capsule is a more challenging task. Each method of scleral fixation has its own advantages and none of them has strong evidence to be superior. This paper describes postsurgical outcomes of two scleral intraocular(IOL) fixation techniques combined with pars plana vitrectomy(PPV) from a single tertiary referral eye center. METHODS: Patients underwent PPV and IOL implantation with either four-point sutured scleral fixation (Akreos AO60(AK); n = 24) or two-point sutureless flanged intrascleral fixation (CT Lucia(CTL); n = 7). Reports include IOL and sclerotomy placement, fixation techniques, and IOL model. RESULTS: Thirty-one eyes of thirty patients were analyzed. Average change in vision from baseline measurement was LogMAR - 0.68 ± 0.66 and - 0.90 ± 0.63 for AK and CTL groups, respectively. Average postoperative refractive error was - 0.3 ± 1.03 D (AK) and 0.4 ± 0.60 D (CTL). No opacification cases of Akreos lens were found in this study with the longest follow up of 53 months. CONCLUSIONS: Both methods of implantation (sutured and sutureless) could provide good visual and refractive outcomes. Minimal complication rates were reported despite including patients with multiple comorbidities, making both techniques an attractive choice for secondary IOL implantation.

Topical Corneal Cross-Linking Solution Delivered Via Corneal Reservoir in Dutch-Belted Rabbits.

Purpose: A topical corneal cross-linking solution that can be used as an adjunct or replacement to standard photochemical cross-linking (UV-riboflavin) methods remain an attractive possibility. Optimal concentration and delivery method for such topical corneal stabilization in the living rabbit eye were developed. Methods: A series of experiments were carried out using Dutch-belted rabbits (3 months old, weighing 1.0-1.5 kg) and topical cross-linking solutions (sodium hydroxymethylglycinate) (10-250 mM) delivered via corneal reservoir. The application regimen included a one-time 30-minute application (10-40 mM sodium hydroxymethylglycinate) as well as a once per week 5-minute application (250 mM sodium hydroxymethylglycinate) for 7 weeks. Animals were evaluated serially for changes in IOP, pachymetry, epithelial integrity, and endothelial cell counts. Keratocyte changes were identified using intravital laser scanning confocal microscopy. Post mortem efficacy was evaluated by mechanical inflation testing. Results: Overall, there were very few differences observed in right eye treated versus left eye controls with respect to intraocular pressure, pachymetry, and endothelial cell counts, although 30-minute cross-linking techniques did cause transient increases in thickness resolving within 7 days. Epithelial damage was noted in all of the 30-minute applications and fully resolved within 72 hours. Keratocyte changes were significant, showing a wound healing pattern similar to that after riboflavin UVA photochemical cross-linking in rabbits and humans. Surprisingly, post mortem inflation testing showed that the lower concentration of 20 mM delivered over 30 minutes showed the most profound stiffening/strengthening effect. Conclusions: Topical cross-linking conditions that are safe and can increase corneal stiffness/strength in the living rabbit eye have been identified. Translational Relevance: A topical corneal cross-linking solution delivered via corneal reservoir is shown to be both safe and effective at increasing tissue strength in living rabbit eyes and could now be tested in patients suffering from keratoconus and other conditions marked by corneal tissue weakness.

Ex vivo anti-microbial efficacy of various formaldehyde releasers against antibiotic resistant and antibiotic sensitive microorganisms involved in infectious keratitis.

BACKGROUND: Corneal infections with antibiotic-resistant microorganisms are an increasingly difficult management challenge and chemically or photochemically cross-linking the cornea for therapy presents a unique approach to managing such infections since both direct microbial pathogens killing and matrix stabilization can occur simultaneously. The present study was undertaken in order to compare the anti-microbial efficacy, in vitro, of 5 candidate cross-linking solutions against 5 different microbial pathogens with relevance to infectious keratitis. METHODS: In vitro bactericidal efficacy studies were carried out using 5 different FARs [diazolidinyl urea (DAU), 1,3-bis(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione (DMDM), sodium hydroxymethylglycinate (SMG), 2-(hydroxymethyl)-2-nitro-1,3-propanediol (NT = nitrotriol), 2-nitro-1-propanol (NP)] against 5 different microbial pathogens including two antibiotic-resistant species [methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Pseudomonas aeruginosa (PA), and Candida albicans (CA)]. Standard in vitro antimicrobial testing methods were used. RESULTS: The results for MSSA were similar to those for MRSA. DAU, DMDM, and SMG all showed effectiveness with greater effects generally observed with longer incubation times and higher concentrations. Against MRSA, 40 mM SMG at 120 min showed a > 95% kill rate, p < 0.02. Against VRE, 40 mM DAU for 120 min showed a > 94% kill rate, p < 0.001. All FARs showed bactericidal effect against Pseudomonas aeruginosa, making PA the most susceptible of the strains tested. Candida showed relative resistance to these compounds, requiring high concentrations (100 mM) to achieve kill rates greater than 50%. CONCLUSION: Our results show that each FAR compound has different effects against different cultures. Our antimicrobial armamentarium could potentially be broadened by DAU, DMDM, SMG and other FARs for antibiotic-resistant keratitis. Further testing in live animal models are indicated.

Epithelial Inclusion Cyst of the Bulbar Conjunctiva Secondary to Scleral Lens Impingement Managed With a MicroVault.

Acquired epithelial inclusion conjunctival bulbar cyst is a reported complication of scleral contact lens impingement commonly corrected with a diameter change or notch of the scleral contact lens. This case discusses an acquired epithelial inclusion conjunctival bulbar cyst due to microtrauma caused by prolonged scleral contact lens wear and corrected with a MicroVault.

Correction: Safety and efficacy of tacrolimus-coated silicone plates as an alternative to mitomycin C in a rabbit model of conjunctival fibrosis.

[This corrects the article DOI: 10.1371/journal.pone.0219194.].

Dupilumab-associated blepharoconjunctivitis.

PURPOSE: To report a case of dupilumab-associated blepharoconjunctivitis. OBSERVATIONS: A 48 year-old Caucasian male presented with bilateral blepharitis, multiple chalazia, dry eye disease and significant papillary conjunctivitis. The past medical history included fourteen years of severe atopic dermatitis. After failed attempts to treat atopic dermatitis with topical corticosteroids, the patient enrolled into a four-year clinical trial of biweekly dupilumab injections. Four to six weeks after initiation of dupilumab, the patient reported blurred vision, ocular irritation and redness. Slit lamp examination demonstrated bilateral meibomian gland dysfunction, edematous eyelids with multiple chalazia and significant papillary conjunctivitis. Meibography by Lipiscan revealed significant truncation, atrophy and bifurcation of meibomian glands bilaterally. The patient's multiple chalazia were excised and eyelid hygiene was closely followed. Cliradex wipes and Avenova were added to the patient's regime and one session of Lipiflow treatment was administered. The patient continued this eyelid hygiene regimen along with neomycin/polymyxin B/dexamethasone ophthalmic ointment after each dupilumab infusion. CONCLUSIONS AND IMPORTANCE: Five weeks after Lipiflow treatment with concomitant use of Cliradex and Avenova, visual acuity and ocular discomfort improved. Current treatment includes Cliradex eyelid wipes along with neomycin/polymyxin B/dexamethasone ophthalmic ointment for a week after each dupilumab infusion. Topical steroids and antibiotics with eyelid hygiene are effective ways to treat atopic dermatitis patients exhibiting dupilumab's ocular side effects. Lipiflow therapy may also help in treatment.

Safety and efficacy of tacrolimus-coated silicone plates as an alternative to mitomycin C in a rabbit model of conjunctival fibrosis.

PURPOSE: To find safer and more effective drugs than mitomycin C to prevent conjunctival fibrosis in a rabbit model. METHODS: Twenty-four rabbits were involved and randomly divided into four groups. Limbus-based peritomy was performed at the superior cornea, and normal saline (NS group), mitomycin C (MMC group), SR (SR group), or TC (TC group)-coated silicone plate was inserted at the sub-Tenon's space in each group. Conjunctival congestion was evaluated at 1 and 4 weeks postoperatively. At 4 weeks, the numbers of inflammatory cells, fibroblasts, myofibroblasts, blood vessels, and goblet cells were counted in the conjunctiva and Tenon's capsule around the silicone plate. RESULTS: At 4 weeks, conjunctival congestion was significantly less than that observed at 1 week in the SR and TC groups (p < 0.05), whereas the number of myofibroblasts was significantly lower in the MMC and TC groups (p < 0.05). The conjunctiva was significantly less congested in the TC group versus the other groups at 1 week and 4 weeks (p < 0.05). The TC group had the lowest number of inflammatory cells and MMC group had the lowest number of goblet cells among all groups (p < 0.05). CONCLUSIONS: The TC-coated silicone plate was more effective in inhibiting inflammation and fibrosis versus the MMC-coated silicone plate and was associated with fewer adverse effects in the rabbit model.

Performance of the Barrett Toric Calculator with and without measurements of posterior corneal curvature.

BACKGROUND: Toric intraocular lens power calculators, e.g., the Barrett Toric Calculator, based on predicted, rather than on measured posterior corneal curvature have yielded the best results so far. However, recent update of the Barrett Toric Calculator aims to fine tune its refractive predictions with the input of measured posterior corneal curvature. Here, we wanted to compare refractive predictions of the Barrett Toric Calculator, based on IOL Master 700 biometry, with and without measurements of posterior corneal curvature. METHODS: In total 30 eyes were included in the study. One-month postoperative manifest refraction and predicted residual refractive error of both formulas were utilized to calculate mean absolute error and centroid error in predicted residual astigmatism. The Pentacam was used to measure posterior corneal curvature. RESULTS: We did not find any statistically significant difference in mean absolute error and centroid error in predicted residual astigmatism between the Barrett Toric Calculator with and without measurement of posterior corneal curvature. Post-hoc analysis of with-the-rule and against-the-rule astigmatic eyes did not reveal any significant differences as well. CONCLUSIONS: Astigmatism prediction errors, based on IOL Master 700 biometry, with and without measured posterior corneal curvature, were similar. To the best of our knowledge, the updated Barrett Toric Calculator is the first formula to provide non-inferior and reliable predictions based on measurement of posterior corneal curvature.

Case Report: Management of Corneal Clouding from Lecithin: Cholesterol Acyltransferase Deficiency.

SIGNIFICANCE: Given that there are few reported cases of lecithin:cholesterol acyltransferase (LCAT) deficiency, recognition of the condition with proper management is notable. Long-term follow-up and contact lens fitting after penetrating keratoplasty provide best possible outcomes. PURPOSE: The purpose of this study was to report a case of LCAT deficiency successfully treated with penetrating keratoplasty and longer-term follow-up with contact lens fitting. CASE REPORT: A 43-year-old white woman of Italian descent presented with corneal clouding and trouble with night vision. The patient had a history of LCAT deficiency, irritable bowel syndrome, gastroesophageal reflux disease, osteoporosis, and hemolytic anemia. Slit-lamp examination demonstrated corneal haze throughout the corneal layers. The corneas had normal pachymetry. Given the opacity of each cornea (right greater than left) and decreased night vision, penetrating keratoplasty was performed on the right eye. At post-operative month 16, the corneal graft remained clear. The patient was able to achieve a best-corrected visual acuity of 20/30+ with a scleral lens. CONCLUSIONS: Penetrating keratoplasty may be necessary to provide better quality of vision in LCAT deficiency patients, specifically to enhance one's contrast sensitivity, despite relatively good Snellen visual acuity.

Interventions and Outcomes in Patients with Infectious Pseudomonas scleritis: A 10-Year Perspective.

Purpose: To identify interventional factors associated with improved visual results and faster time to resolution for patients with Pseudomonas scleritis. Methods: Retrospective study analyzing inciting factors, therapeutic modalities, and outcomes of patients with Pseudomonas scleritis. Results: A total of 24 patients were analyzed; 22 were treated as outpatients. All had resolution of infection and 58% (n = 14) maintained ≥20/200 vision. Medical therapy included topical and oral antibiotics; seven received additional subconjunctival injections; two were admitted for IV antibiotics. Patients presenting with ≥20/200 vision were more likely to maintain this level of vision (n = 8, 80%) compared to those presenting with severe vision loss (n = 5, 36%) (p = 0.04). A similar proportion of patients who received (n = 8, 61%) and did not receive (n = 5, 39%) oral steroids achieved 20/200 vision or better once infection resolved, p = 1.0. Conclusions: Pseudomonas scleritis can be successfully managed in the outpatient setting. Oral steroids do not appear harmful in the treatment of this disease.

DIFFERENCES IN REFRACTIVE OUTCOMES BETWEEN PHACOEMULSIFICATION FOR CATARACT ALONE AND COMBINED PHACOEMULSIFICATION AND VITRECTOMY FOR EPIRETINAL MEMBRANE.

PURPOSE: To determine whether preoperative adjustments are required for intraocular lens calculations in combined phacovitrectomy surgery. METHODS: A single-center, retrospective study of 50 eyes that underwent combined phacovitrectomy and a control group of 50 eyes after cataract surgery over a 3-year period by a single anterior segment surgeon and a single posterior segment surgeon. Main outcome measures were predicted refractive error (RE), as determined by SRK/T and Holladay 1 formulas, change compared with actual RE, surgically induced astigmatism, and the relationships between preoperative central foveal thickness or change in central foveal thickness and final RE. RESULTS: The differences in predicted and final RE between groups were not statistically significant between groups when both SRK/T and Holladay 1 formulas were used (P > 0.05). Regardless of the formula used, final RE was neither significantly hyperopic nor myopic as compared to the target. There was no difference in surgically induced astigmatism between the two groups. Increased preoperative central foveal thickness was correlated with greater difference between predicted and actual RE. No relationship was noted between change in central foveal thickness and RE. CONCLUSION: Combined phacovitrectomy for concurrent cataract epiretinal membrane by experienced cataract and vitreoretinal surgeons seems to deliver as predictable refractive results as cataract surgery alone.

An Ultraflexible and Stretchable Aptameric Graphene Nanosensor for Biomarker Detection and Monitoring.

An ultraflexible and stretchable field-effect transistor nanosensor is presented that uses aptamer-functionalized monolayer graphene as the conducting channel. Specific binding of the aptamer with the target biomarker induces a change in the carrier concentration of the graphene, which is measured to determine the biomarker concentration. Based on a Mylar substrate that is only 2.5-µm thick, the nanosensor is capable of conforming to underlying surfaces (e.g., those of human tissue or skin) that undergo large bending, twisting, and stretching deformations. In experimental testing, the device is rolled on cylindrical surfaces with radii down to 40 µm, twisted by angles ranging from -180° to 180°, or stretched by extensions up to 125%. With these large deformations applied either cyclically or non-recurrently, the device is shown to incur no visible mechanical damage, maintain consistent electrical properties, and allow detection of TNF-α, an inflammatory cytokine biomarker, with consistently high selectivity and low limit of detection (down to 5 × 10-12M). The nanosensor can thus potentially enable consistent and reliable detection of liquid-borne biomarkers on human skin or tissue surfaces that undergo large mechanical deformations.

Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis.

BACKGROUND: Corneal collagen crosslinking (CXL) is a widely used treatment for halting the progression of keratoconus. Although initial studies of CXL were performed with a riboflavin solution containing dextran, recent protocols for CXL have indicated the use of a riboflavin solution containing isotonic hydroxypropyl methylcellulose (HPMC). This study was performed to investigate differences in visual outcomes and Scheimpflug (Pentacam) analysis in patients who have undergone epithelium-off CXL with riboflavin solution containing either 20% dextran versus 1.1% HPMC. METHODS: All patients in this non-randomized, non-masked, retrospective cohort analysis were treated at Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA. Thirty-seven eyes of 33 patients were crosslinked with a dextran solution and 19 eyes of 19 patients crosslinked with an isotonic HPMC solution, both using an epithelium-off 30-min, 3 mW/cm2 protocol. All patients had a diagnosis of keratoconus or post-refractive surgery ectasia. Best spectacle corrected visual acuity (BSCVA) and Pentacam parameters were compared at all follow up visits (1, 6, 12, and 24 months). Differences between groups treated with HPMC and dextran were compared using student's t-test. Differences between treated eye and fellow eye were calculated and compared between HPMC and dextran groups using paired t-test. RESULTS: Patients treated with a dextran solution had significantly greater improvement in BSCVA at 1, 6, and 24 months (p < 0.05) compared to the isotonic HPMC-treated group. Kmax increased in both groups at 1 month; however, HPMC-treated patients had a greater increase compared to dextran-treated patients (p = 0.01). Kmax decreased in both groups at 6 and 12 months, although this finding was only significant in the HPMC-treated group at 12 months. CONCLUSIONS: Our data suggest that crosslinking with the dextran solution may result in significantly better visual outcomes (demonstrated by visual acuity) compared to the isotonic HPMC riboflavin solution. Dextran solutions may have other potential advantages intrinsic to its biochemical properties facilitating more efficient crosslinking. Further research and long-term evidence regarding the use of dextran versus HPMC riboflavin solutions in collagen crosslinking is necessary.

Correlation of Scheimpflug densitometry changes with clinical outcomes after corneal crosslinking.

PURPOSE: To characterize changes in densitometry after corneal crosslinking (CXL) and correlate it with visual outcomes. SETTING: Tertiary referral academic medical center, New York, New York, USA. DESIGN: Retrospective case series. METHODS: Patients with progressive keratoconus or post-laser in situ keratomileusis ectasia had CXL following the Dresden protocol. The corrected distance visual acuity (CDVA) and Pentacam imaging were obtained at baseline and follow-up visits. RESULTS: Fifty-seven patients were followed for a mean of 15 months (range 1 to 24 months) after CXL. The CDVA improved significantly from baseline to 6, 12, 18, and 24 months postoperatively. The change in densitometry of the mid-stromal layer, 2.0 to 6.0 mm annulus, at 6 months was correlated with the improvement in CDVA at 6, 12, and 24 months (all P < .10). The increase in densitometry of the mid-stromal layer, centermost 0.0 to 2.0 mm annulus, at 6 months was significantly associated with the decrease in maximum keratometry (K) at 6 and 12 months (both P < .05). Last, the change in densitometry at 6 months was significantly correlated with the decrease in specific higher-order aberrations (HOAs) (P < .05). CONCLUSIONS: Although the greatest and most durable post-CXL densitometry change was in the anterior layer, the degree of increased densitometry haze in the mid-stromal layer was most associated with and possibly predictive of improvement in CDVA, maximum K, and HOAs. The persistence of corneal haze at 6 months, measured by increased densitometry, might be a prognostic marker for CXL effectiveness.

Using Anterior Segment Optical Coherence Tomography to Monitor Disease Progression in Peripheral Ulcerative Keratitis.

We report two cases of peripheral ulcerative keratitis (PUK) imaged with anterior segment optical coherence tomography (AS-OCT). The first patient had prolonged nonsteroidal anti-inflammatory drug use, while the second had inflammatory arthritis by laboratory findings without any systemic findings as well as possible concurrent tuberculosis. In both patients, AS-OCT demonstrated corneal thinning at the onset of the disease with improvement six months after initiation of intensive medical therapy. Our cases highlight the need for a multidisciplinary approach and careful monitoring in PUK cases, especially with objective measures such as corneal thickness assessed with AS-OCT.

Antimicrobial Studies Using the Therapeutic Tissue Cross-Linking Agent, Sodium Hydroxymethylglycinate: Implication for Treating Infectious Keratitis.

Purpose: Our recent studies raise the possibility of using sodium hydroxymethylglycinate (SMG), for pharmacologic therapeutic tissue cross-linking (TXL) of the cornea. The present study was performed to evaluate the antimicrobial effects of SMG for potential use in treating infectious keratitis. Methods: In initial (group 1) experiments, methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (PA) were treated with SMG (10-40 mM) for 10 to 120 minutes. In group 2 experiments, MRSA, PA, Candida albicans (CA), and vancomycin-resistant Enterococcus (VRE) were treated with SMG (20-200 mM) for 30 minutes. In group 2 experiments, BSA and neutralizing buffer were added to provide a proteinaceous medium, and to ensure precise control of SMG exposure times, respectively. SMG effectiveness was quantitated based on pathogen growth following a 24- to 48-hour incubation period. Results: In group 1 experiments, as expected, time- and concentration-dependent bactericidal effects were noted using MSSA. In addition, the effect of SMG (40 mM) was greatest against MSSA (99.3%), MRSA (96.0%), and PA (97.4%) following a 2-hour exposure with lesser effects following 30- and 10-minute exposures. In group 2 experiments, concentration-dependent bactericidal effects were confirmed for MRSA (91%), PA (99%), and VRE (55%) for 200-mM SMG with 30-minute treatment. SMG was not as effective against CA, with a maximum kill rate of 37% at 80 mM SMG. Conclusions: SMG solution exhibits a dose-dependent bactericidal effect on MSSA, MRSA, and PA, with milder effects on VRE and CA. These studies raise the possibility of using SMG TXL for the treatment of infectious keratitis.