Early Real-World Patient and Staff Experience with an Intracanalicular Dexamethasone Insert.

Purpose: To evaluate both the early experience of real-world patients treated with dexamethasone ophthalmic insert (0.4 mg; DEXTENZA®), hereafter referred to as DEX, after cataract surgery as well as staff/practice integration of DEX relative to eyedrops. Patients and Methods: This was a cross-sectional survey study of 23 cataract practices in the United States. Respondents were patients and practice staff who had experience with DEX following cataract surgery. Both patients and practice staff completed an online survey. Descriptive statistics summarized the survey responses to portray the experience of the respondents. Results: Surveys were completed by 62 patients and 19 practice staff. Almost all patients (93%) were satisfied or extremely satisfied with DEX. Patients highly preferred DEX (93%) to topical steroid drops (7%) based on past experiences with topical steroid drops. Most practice staff (95%) were satisfied or highly satisfied with DEX, reporting a 45% reduction in time spent educating patients on postoperative drop use and a 46% decrease in time spent addressing calls from pharmacies regarding postoperative medications. Conclusion: Incorporating the DEX insert into clinical practice in cataract surgery practices can improve patient adherence, while potentially providing significant savings to practices in terms of time spent educating patients and responding to patient and pharmacy call-backs.

Effects of Punctal Occlusion on Ocular Itching and Conjunctival Redness Associated with Allergic Conjunctivitis.

PURPOSE: Punctal occlusion using punctal plugs has been successfully used to treat the signs and symptoms of dry eye disease. However, the effects of punctal occlusion on the symptoms of allergic conjunctivitis (AC) have been less well documented. There is some concern among clinicians that punctal occlusion may make signs/symptoms of allergic conjunctivitis worse by trapping allergens on the eye. The objective of this post hoc analysis was to address this question and thus assess the effect of punctal occlusion alone on ocular itching and conjunctival redness associated with AC. METHODS: This was a pooled post hoc analysis of three randomized, double-blind, placebo insert-controlled clinical trials in subjects with AC. Enrolled subjects were generally healthy adults with ocular allergies and a positive skin test reaction to perennial and/or seasonal allergens. The study used a modified version of the traditional conjunctival allergen challenge (CAC) model, which included multiple, repeated allergen challenges following placement of the intracanalicular insert. Subjects were rechallenged on Days 6, 7 and 8; Days 13, 14 and 15; and Days 26, 27 and 28. RESULTS: The data set included 128 subjects that were administered placebo. Baseline mean (SD) ocular itching and conjunctival redness scores were 3.52 (0.44) and 2.97 (0.39), respectively. On post-insertion Days 7, 14 and 28, mean itching scores were 2.62, 2.26 and 1.91, respectively, representing 26%, 36% and 46% itching reductions, respectively (p < 0.001). On Days 7, 14 and 28, mean conjunctival redness scores were 1.98, 1.90, and 2.08, respectively, representing 33%, 36%, and 30% redness reductions, respectively (p < 0.001). CONCLUSIONS: Based on this post hoc pooled analysis, punctal occlusion with a resorbable hydrogel intracanalicular insert did not worsen ocular itching or conjunctival redness in this patient population.

Identifying and addressing common contributors to nonadherence with ophthalmic medical therapy.

PURPOSE OF REVIEW: To discuss common reasons for nonadherence and review existing and emerging options to reduce nonadherence with ocular medical therapy and optimize therapeutic outcomes. RECENT FINDINGS: Nonadherence can arise from patient-related issues (e.g. physical, cognitive) and healthcare-related issues (e.g. cost, access to care). Multiple strategies have been developed and evaluated to overcome these barriers to adherence. Identifying nonadherence and its cause(s) facilitates the development of strategies to overcome it. SUMMARY: Many common causes of nonadherence can be mitigated through a variety of strategies presented.

Early Real-World Physician Experience with an Intracanalicular Dexamethasone Insert.

Purpose: To describe the early real-world experience of physicians with an intracanalicular dexamethasone insert (DEX) in patients undergoing cataract surgery and to capture the clinical impact of adopting this therapy. Patients and Methods: 23 United States sites including Ambulatory Surgical Center Setting (ASC) and Outpatient Clinical settings. Respondents were physicians who had early experience with DEX in cataract surgery patients. This was a Phase 4 experiential cross-sectional survey study comprised of 3 sequential online physician surveys. Descriptive statistics summarized the surveys' responses to determine the early impressions of the respondents. Results: Forty-two physicians completed surveys. On average, physicians reported feeling comfortable administering DEX after placing 3 inserts (mean 2.7; standard deviation 1.9). Most physicians (92%) were satisfied with DEX, and all physicians (100%) reported that DEX improved patient compliance. Most physicians (62.5%) indicated they would highly prefer DEX over traditional steroid eyedrops for the management of post-surgical inflammation and pain. Conclusion: The surveys exploring the early use of DEX suggest that DEX is a clinically effective treatment with a rapid initial learning curve and integrates well into clinical use. Physicians had a very positive early experience with DEX, including comfort with insertion and satisfaction. DEX shows promise as a primary treatment choice of physicians for ocular inflammation and pain following cataract surgery by offering patients a hands-free innovative therapy that delivers a preservative-free steroid to the ocular surface over approximately 30 days.

Ocular benzalkonium chloride exposure: problems and solutions.

Preservatives in multidose formulations of topical ophthalmic medications are crucial for maintaining sterility but can be toxic to the ocular surface. Benzalkonium chloride (BAK)-used in approximately 70% of ophthalmic formulations-is well known to cause cytotoxic damage to conjunctival and corneal epithelial cells, resulting in signs and symptoms of ocular surface disease (OSD) including ocular surface staining, increased tear break-up time, and higher OSD symptom scores. These adverse effects are more problematic with chronic exposure, as in lifetime therapy for glaucoma, but can also manifest after exposure as brief as seven days. Multiple strategies are available to minimize or eliminate BAK exposure, among them alternative preservatives, preservative-free formulations including sustained release drug delivery platforms, and non-pharmacological therapies for common eye diseases and conditions. In this paper, we review the cytotoxic and clinical effects of BAK on the ocular surface and discuss existing and emerging options for ocular disease management that can minimize or eliminate BAK exposure.

Plasma Pharmacokinetic Parameters of Dexamethasone Following Administration of a Dexamethasone Intracanalicular Insert in Healthy Adults.

PURPOSE: Intracanalicular dexamethasone insert is a resorbable sustained-release polyethylene glycol-based hydrogel insert delivering a 0.4 mg tapered dose of dexamethasone for up to 30 days to the ocular surface. It is FDA-approved for treating inflammation and pain after ocular surgery. It has also been studied for ocular surface diseases such as allergic conjunctivitis. This study assessed the plasma pharmacokinetic (PK) parameters of dexamethasone following intracanalicular insertion. PATIENTS AND METHODS: Study subjects (N=16) were healthy adults. A dexamethasone insert was unilaterally placed into the canaliculus, and blood samples were obtained for analysis 1 hour prior to insertion and 1, 2, 4, 8, 16, 24 hours and 4, 8, 15, 22 and 29 days after insertion. Safety analyses included slit lamp and dilated fundus examinations, best corrected visual acuity, intraocular pressure (IOP) and adverse events (AEs). RESULTS: Plasma results were below the lower limit of quantitation (LLOQ) at all time points in five subjects (31.3%). Among subjects with quantifiable plasma concentrations, Cmax was <1 ng/mL (range, 0.05 to 0.81 ng/mL), AUC0-last ranged from 0.13 to 7.18 h∙ng/mL, and Tmax ranged from 4.0 to 163.0 hours. Mean (SD) IOP increased from 16.3 (1.4) mmHg at baseline to 19.3 (3.2) at Day 22 but returned to baseline after treatment. No changes occurred in dilated fundus, punctum, or visual acuity examinations. CONCLUSION: The dexamethasone 0.4 mg insert results in minimal systemic exposure following intracanalicular administration.

Phase 3 Randomized Study of Efficacy and Safety of a Dexamethasone Intracanalicular Insert in Patients With Allergic Conjunctivitis.

PURPOSE: The purpose of this study was to evaluate the efficacy and safety of a dexamethasone intracanalicular ocular insert for the treatment of allergic conjunctivitis. DESIGN: Multicenter, randomized, double-masked, placebo-controlled, Phase 3 clinical trial. METHODS: Subjects with allergic conjunctivitis were randomized 1:1 to receive a dexamethasone insert or a placebo insert in both eyes and were evaluated using a modified version of the conjunctival allergen challenge (CAC) model. After inserts were placed in office, a series of 4 closely spaced post-insertion CACs were conducted at weeks 1, 2, and 4 across approximately 30 days. Primary efficacy endpoints, assessed at week-1 CAC-day 8, were reported by subjects of ocular itching at 3, 5, and 7 minutes post CAC and investigator-evaluated conjunctival redness at 7, 15, and 20 minutes post CAC. RESULTS: For the primary endpoints, dexamethasone inserts showed statistically significantly lower mean ocular itching scores than placebo at all time points (P <.001), with differences favoring dexamethasone inserts over placebo (0.86, 0.98, and 0.96 units at 3, 5, and 7 minutes, respectively) and statistically significantly lower conjunctival redness scores at 20 minutes (P <.05) but not at 7 or 15 minutes (P ≥.05). Results also showed statistically significantly less itching and conjunctival redness at 31 and 29 of 33 other time points, respectively (P <.05). There were no serious adverse events; 1 subject had elevated intraocular pressure in both eyes. CONCLUSIONS: Data presented in this study demonstrate the potential for a single, physician-administered dexamethasone intracanalicular insert to provide relief of ocular itching for up to 4 weeks in subjects with allergic conjunctivitis, while maintaining a favorable safety profile.

Dropless cataract surgery: modernizing perioperative medical therapy to improve outcomes and patient satisfaction.

PURPOSE OF REVIEW: Advances in pharmacology offer freedom from topical medical therapy without compromise of anti-inflammatory and antimicrobial coverage in the perioperative period. In this review, we describe the basis for dropless cataract surgery with the goal of improving outcomes and the patient experience. RECENT FINDINGS: Phacoemulsification outcomes depend largely on surgeon skill but also on adherence to a complex multidrug regimen of perioperative anti-inflammatory and antimicrobial therapy to prevent sight-threatening complications such as cystoid macular edema or endophthalmitis. Successful administration of this regimen can be limited by noncompliance, difficulty administering eye drops, bioavailability, and side effects, among others. The recent development of sustained-release formulations of dexamethasone - one an intracanalicular insert and the other an intraocular suspension - can provide sustained tapering doses of dexamethasone while reducing or eliminating the need for anti-inflammatory eye drop therapy. Similarly, mounting evidence compellingly demonstrates that intracameral antibiotic use intraoperatively is at least as effective as topical antibiotics in preventing endophthalmitis. SUMMARY: Sustained-release dexamethasone coupled with intracameral antibiotics at the time of phacoemulsification can provide antimicrobial and anti-inflammatory prophylaxis without the need for topical eye drop medications. This approach has the potential to improve compliance with therapy, visual acuity outcomes, and the overall patient experience.

Punctum and canalicular anatomy for hydrogel-based intracanalicular insert technology.

Aim: Despite advances in cataract surgery, postoperative ocular inflammation and pain occurs. To address compliance issues with topical corticosteroid administration, a hydrogel-based dexamethasone insert was developed for intracanalicular administration. The objective is to understand the anatomy to best administer the insert and learn how the anatomy and hydrogel properties help retain the insert in the canaliculus over time. Materials & methods: Human cadavers (n = 5) were dissected to assess dimensions of punctum and canaliculus as part of drug discovery and development. Results & conclusions: Mean measures for punctal diameter was 0.5 ± 0 mm and vertical canaliculi length was 2.4 ± 0.5 mm and width was 1.6 ± 0.5 mm. Vertical canalicular width was larger than the punctal opening, a critical understanding for placing and retaining intracanalicular inserts.

Quantifying the effects of hydration on corneal stiffness with noncontact optical coherence elastography.

PURPOSE: To quantify the effects of the hydration state on the Young's modulus of the cornea. SETTING: Biomedical Optics Laboratory, University of Houston, Houston, Texas, USA. DESIGN: Experimental study. METHODS: Noncontact, dynamic optical coherence elastography (OCE) measurements were taken of in situ rabbit corneas in the whole eye-globe configuration (n = 10) and at an artificially controlled intraocular pressure of 15 mm Hg. Baseline OCE measurements were taken by topically hydrating the corneas with saline for 1 hour. The corneas were then dehydrated topically with a 20% dextran solution for another hour, and the OCE measurements were repeated. A finite element method was used to quantify the Young's modulus of the corneas based on the OCE measurements. RESULTS: The thickness of the corneas shrank considerably after topical addition of the 20% dextran solution (∼680 µm to ∼370 µm), and the OCE-measured elastic-wave speed correspondingly decreased (∼3.2 m/s to ∼2.6 m/s). The finite element method results showed an increase in Young's modulus (500 kPa to 800 kPa) resulting from dehydration and subsequent thinning. CONCLUSION: Young's modulus increased significantly as the corneas dehydrated and thinned, showing that corneal geometry and hydration state are critical factors for accurately quantifying corneal biomechanical properties.

Effects of Thickness on Corneal Biomechanical Properties Using Optical Coherence Elastography.

SIGNIFICANCE: Measured corneal biomechanical properties are driven by intraocular pressure, tissue thickness, and inherent material properties. We demonstrate tissue thickness as an important factor in the measurement of corneal biomechanics that can confound short-term effects due to UV riboflavin cross-linking (CXL) treatment. PURPOSE: We isolate the effects of tissue thickness on the measured corneal biomechanical properties using optical coherence elastography by experimentally altering the tissue hydration state and stiffness. METHODS: Dynamic optical coherence elastography was performed using phase-sensitive optical coherence tomography imaging to quantify the tissue deformation dynamics resulting from a spatially discrete, low-force air pulse (150-µm spot size; 0.8-millisecond duration; <10 Pa [<0.08 mmHg]). The time-dependent surface deformation is characterized by a viscoelastic tissue recovery response, quantified by an exponential decay constant-relaxation rate. Ex vivo rabbit globes (n = 10) with fixed intraocular pressure (15 mmHg) were topically instilled every 5 minutes with 0.9% saline for 60 minutes and 20% dextran for another 60 minutes. Measurements were made after every 20 minutes to determine the central corneal thickness (CCT) and the relaxation rates. Cross-linking treatment was performed on another 13 eyes, applying isotonic riboflavin (n = 6) and hypertonic riboflavin (n = 7) every 5 minutes for 30 minutes, followed by UV irradiation (365 nm, 3 mW/cm) for 30 minutes while instilling riboflavin. Central corneal thickness and relaxation rates were obtained before and after CXL treatment. RESULTS: Corneal thickness was positively correlated (R = 0.9) with relaxation rates. In the CXL-treated eyes, isotonic riboflavin did not affect CCT and showed a significant increase in relaxation rates (+10%; P = .01) from 2.29 ms to 2.53 ms. Hypertonic riboflavin showed a significant CCT decrease (-31%; P = .01) from 618 µm to 429 µm but showed little change in relaxation rates after CXL treatment. CONCLUSIONS: Corneal thickness and stiffness are correlated positively. A higher relaxation rate implied stiffer material properties after isotonic CXL treatment. Hypertonic CXL treatment results in a stiffness decrease that offsets the stiffness increase with CXL treatment.

Optical coherence elastography for evaluating customized riboflavin/UV-A corneal collagen crosslinking.

UV-induced collagen cross-linking is a promising treatment for keratoconus that stiffens corneal tissue and prevents further degeneration. Since keratoconus is generally localized, the efficacy of collagen cross-linking (CXL) treatments could be improved by stiffening only the weakened parts of the cornea. Here, we demonstrate that optical coherence elastography (OCE) can spatially resolve transverse variations in corneal stiffness. A short duration ( ? 1 ?? ms ) focused air-pulse induced low amplitude ( ? 10 ?? ? m ) deformations in the samples that were detected using a phase-stabilized optical coherence tomography system. A two-dimensional map of material stiffness was generated by measuring the damped natural frequency (DNF) of the air-pulse induced response at various transverse locations of a heterogeneous phantom mimicking a customized CXL treatment. After validation on the phantoms, similar OCE measurements were made on spatially selective CXL-treated in situ rabbit corneas. The results showed that this technique was able to clearly distinguish the untreated and CXL-treated regions of the cornea, where CXL increased the DNF of the cornea by ? 51 % . Due to the noncontact nature and minimal excitation force, this technique may be valuable for in vivo assessments of corneal biomechanical properties.

Optical coherence elastography assessment of corneal viscoelasticity with a modified Rayleigh-Lamb wave model.

The biomechanical properties of the cornea play a critical role in forming vision. Diseases such as keratoconus can structurally degenerate the cornea causing a pathological loss in visual acuity. UV-A/riboflavin corneal collagen crosslinking (CXL) is a clinically available treatment to stiffen the cornea and restore its healthy shape and function. However, current CXL techniques do not account for pre-existing biomechanical properties of the cornea nor the effects of the CXL treatment itself. In addition to the inherent corneal structure, the intraocular pressure (IOP) can also dramatically affect the measured biomechanical properties of the cornea. In this work, we present the details and development of a modified Rayleigh-Lamb frequency equation model for quantifying corneal biomechanical properties. After comparison with finite element modeling, the model was utilized to quantify the viscoelasticity of in situ porcine corneas in the whole eye-globe configuration before and after CXL based on noncontact optical coherence elastography measurements. Moreover, the viscoelasticity of the untreated and CXL-treated eyes was quantified at various IOPs. The results showed that the stiffness of the cornea increased after CXL and that corneal stiffness is close to linear as a function of IOP. These results show that the modified Rayleigh-Lamb wave model can provide an accurate assessment of corneal viscoelasticity, which could be used for customized CXL therapies.

Noncontact Elastic Wave Imaging Optical Coherence Elastography for Evaluating Changes in Corneal Elasticity Due to Crosslinking.

The mechanical properties of tissues can provide valuable information about tissue integrity and health and can assist in detecting and monitoring the progression of diseases such as keratoconus. Optical coherence elastography (OCE) is a rapidly emerging technique, which can assess localized mechanical contrast in tissues with micrometer spatial resolution. In this work we present a noncontact method of optical coherence elastography to evaluate the changes in the mechanical properties of the cornea after UV-induced collagen cross-linking. A focused air-pulse induced a low amplitude (µm scale) elastic wave, which then propagated radially and was imaged in three dimensions by a phase-stabilized swept source optical coherence tomography (PhS-SSOCT) system. The elastic wave velocity was translated to Young's modulus in agar phantoms of various concentrations. Additionally, the speed of the elastic wave significantly changed in porcine cornea before and after UV-induced corneal collagen cross-linking (CXL). Moreover, different layers of the cornea, such as the anterior stroma, posterior stroma, and inner region, could be discerned from the phase velocities of the elastic wave. Therefore, because of noncontact excitation and imaging, this method may be useful for in vivo detection of ocular diseases such as keratoconus and evaluation of therapeutic interventions such as CXL.

Evaluating the Effects of Riboflavin/UV-A and Rose-Bengal/Green Light Cross-Linking of the Rabbit Cornea by Noncontact Optical Coherence Elastography.

PURPOSE: The purpose of this study was to use noncontact optical coherence elastography (OCE) to evaluate and compare changes in biomechanical properties that occurred in rabbit cornea in situ after corneal collagen cross-linking by either of two techniques: ultraviolet-A (UV-A)/riboflavin or rose-Bengal/green light. METHODS: Low-amplitude (≤10 µm) elastic waves were induced in mature rabbit corneas by a focused air pulse. Elastic wave propagation was imaged by a phase-stabilized swept source OCE (PhS-SSOCE) system. Corneas were then cross-linked by either of two methods: UV-A/riboflavin (UV-CXL) or rose-Bengal/green light (RGX). Phase velocities of the elastic waves were fitted to a previously developed modified Rayleigh-Lamb frequency equation to obtain the viscoelasticity of the corneas before and after the cross-linking treatments. Micro-scale depth-resolved phase velocity distribution revealed the depth-wise heterogeneity of both cross-linking techniques. RESULTS: Under standard treatment settings, UV-CXL significantly increased the stiffness of the corneas by ∼47% (P < 0.05), but RGX did not produce statistically significant increases. The shear viscosities were unaffected by either cross-linking technique. The depth-wise phase velocities showed that UV-CXL affected the anterior ∼34% of the corneas, whereas RGX affected only the anterior ∼16% of the corneas. CONCLUSIONS: UV-CXL significantly strengthens the cornea, whereas RGX does not, and the effects of cross-linking by UV-CXL reach deeper into the cornea than cross-linking effects of RGX under similar conditions.

Quantitative assessment of corneal viscoelasticity using optical coherence elastography and a modified Rayleigh-Lamb equation.

We demonstrate the use of a modified Rayleigh­Lamb frequency equation in conjunction with noncontact optical coherence elastography to quantify the viscoelastic properties of the cornea. Phase velocities of air-pulse-induced elastic waves were extracted by spectral analysis and used for calculating the Young's moduli of the samples using the Rayleigh­Lamb frequency equation (RLFE). Validation experiments were performed on 2% agar phantoms (n » 3) and then applied to porcine corneas (n » 3) in situ. The Young's moduli of the porcine corneas were estimated to be ∼60 kPa with a shear viscosity ∼0.33 Pa · s. The results demonstrate that the RLFE is a promising method for noninvasive quantification of the corneal biomechanical properties and may potentially be useful for clinical ophthalmological applications.

Spatial characterization of corneal biomechanical properties with optical coherence elastography after UV cross-linking.

Corneal collagen cross-linking (CXL) is a clinical treatment for keratoconus that structurally reinforces degenerating ocular tissue, thereby limiting disease progression. Clinical outcomes would benefit from noninvasive methods to assess tissue material properties in affected individuals. Regional variations in tissue properties were quantified before and after CXL in rabbit eyes using optical coherence elastography (OCE) imaging. Low-amplitude (<1µm) elastic waves were generated using micro air-pulse stimulation and the resulting wave amplitude and speed were measured using phase-stabilized swept-source OCE. OCE imaging following CXL treatment demonstrates increased corneal stiffness through faster elastic wave propagation speeds and lower wave amplitudes.