Infrared meibography allows detection of dimensional changes in meibomian glands following intranasal neurostimulation

Efficacy of Extranasal Neurostimulation for Patients With Neuropathic Corneal Pain: A Pilot Study

PURPOSE

Neuropathic corneal pain (NCP) has been recognized as a distinct disease, yet treatment options remain limited. The aim of this pilot study was to explore the effectiveness of extranasal neurostimulation (EXNS) as a potential pain relief strategy for individuals with the peripheral component of NCP.

METHODS

A retrospective study was performed to identify patients who were diagnosed with refractory peripheral or mixed NCP and subsequently underwent a single session of EXNS. Visual analog scale (VAS) was used to evaluate pain intensities in the office before and after 60 seconds of EXNS. Demographic information, changes in pain scores, and comorbidities were recorded, and their correlations with pain score changes were analyzed.

RESULTS

Twenty-two patients with a mean age of 48.91 ± 3.32 years were included. The average VAS score before EXNS was 5.59 ± 0.41, which was reduced to 2.59 ± 0.43 after EXNS, indicating a 54.88% reduction (P < 0.001). EXNS reduced VAS scores from 4.90 ± 0.72 to 1.60 ± 0.42 (68.40%) for 10 patients with peripheral NCP and from 6.17 ± 0.42 to 3.42 ± 0.62 (43.61%) for 12 patients with mixed (peripheral and central) NCP (P = 0.005 for both groups). Fourteen patients (63.63%) experienced an improvement of at least 50% in their pain scores, 2 patients (9.09%) showed an improvement between 30% and 49.9%, while 6 patients (27.27%) experienced an improvement of less than 30%. No correlations between the change in pain scores and patient demographics, as well as comorbidities were detected.

CONCLUSIONS

EXNS may be used as an adjuvant therapy to ameliorate pain among patients with NCP with the peripheral pain component.

Meibomian Gland Shortening Is Associated With Altered Meibum Composition

Purpose

The purpose of this study was to investigate differences in the composition of meibum extracted from human meibomian glands displaying different morphological characteristics.

Methods

Adult participants with evidence of meibomian gland shortening were enrolled. Glands were observed using infrared meibography, and meibum was collected from one short and one long gland from the lower eyelid of the same eye. Total protein concentration was evaluated using the detergent compatible (DC) protein assay and lipid analysis was performed using liquid chromatography mass spectrometry.

Results

Fifteen participants (8 women and 7 men) completed the study (mean age = 34.7 ± 7.7 years). The average volume of meibum collected from the short and long glands was 0.02 ± 0.01 and 0.05 ± 0.03 µL, respectively (P = 0.01). Average protein concentration in the short glands was significantly higher compared to the long glands (0.10 ± 0.03 vs. 0.08 ± 0.02 mg/mL, P = 0.01). Among the non-polar lipids, the mole percent of cholesterol esters (CEs; P = 0.02), triacylglycerols (TAGs; P = 0.04), and ceramide (Cer; P = 0.03) was significantly lower in short glands compared with long glands. Among the polar lipids, the mole percent of (O-acyl)-ω-hydroxy fatty acid (OAHFA; P = 0.01) was significantly lower in short glands, whereas phosphatidylcholine (PC; P = 0.02) and sphingomyelin (SM; P = 0.01) were significantly higher in short glands than long glands.

Conclusions

Meibum composition differed between short and long glands. The lower mole percent of CE, TAG, OAHFA, and Cer and a higher mole percent of PC and SM among short glands may indicate disease activity. This information may clarify the natural history of meibomian gland dysfunction and future targets for therapy.

Effectiveness of Intranasal Tear Neurostimulation for Treatment of Dry Eye Disease: A Meta-Analysis

INTRODUCTION

To assess the effectiveness and safety of intranasal tear neurostimulation in the treatment of dry eye disease.

METHODS

We performed a meta-analysis of four databases from their inception to October 2022 without language restrictions. Randomized controlled trials and non-randomized controlled trials meeting the inclusion criteria were included in this review and were quality appraised. The risk of bias was evaluated by two independent reviewers using the Cochrane Collaboration Tool and Methodological Index for Non-Randomized Studies. The random-effect model or fixed-effect model was adopted to estimate the pooled effect sizes.

RESULTS

Fifteen published studies consisting of 17 clinical trials with a total of 901 patients were analyzed. Schirmer II test scores were significantly higher after intranasal tear neurostimulation in patients with dry eye disease (mean difference = 14.12 mm, 95% confidence intervals (8.93, 19.31), P < 0.001). Intranasal tear neurostimulation increased the meibomian gland areas (mean difference = - 251.79 μm², 95% confidence intervals (- 348.34, - 155.23), P < 0.001), but no significant difference was found in meibomian gland perimeters before and after stimulation (mean difference = 3.72 mm, 95% confidence intervals (- 22.14, 29.59), P = 0.78). All adverse events were mild or moderate, and no serious adverse events were reported.

CONCLUSIONS

This meta-analysis provides promising evidence for the controversial effectiveness of intranasal tear neurostimulation in the treatment of dry eye disease, along with useful information for guiding intranasal tear neurostimulation in future clinical trials.

TRIAL REGISTRATION

This meta-analysis was registered on the Prospective Register of Systematic Reviews (PROSPERO) (CRD42021284214).

Efficacy and Safety of Single-Dose OC-02 (Simpinicline Solution) Nasal Spray on Signs and Symptoms of Dry Eye Disease: The PEARL Phase II Randomized Trial

PURPOSE

Dry eye disease is a multifactorial disorder that affects the ocular surface, with symptoms including ocular irritation, impaired vision, and pain. Nicotinic acetylcholine receptor (nAChR) agonists are novel treatments for dry eye disease; this study investigates the nAChR agonist OC-02 (simpinicline solution) as an aqueous nasal spray.

METHODS

PEARL (Clinical Trial to Evaluate the Efficacy of OC-02 Nasal Spray on Signs and Symptoms of Dry Eye Disease) was a Phase II study that evaluated the efficacy and safety of OC-02 (simpinicline solution) nasal spray (OC-02 SNS) in adult patients with dry eye disease. Patients ≥22 years of age were eligible if they had an Ocular Surface Disease Index score ≥23, corneal fluorescein staining score ≥2 in >1 region or ≥4 for all regions, or Schirmer test score (STS) ≤10 mm; there were no restrictions on eye dryness score (EDS). Patients (N = 165) were randomly assigned 1:1:1:1 to vehicle (control; n = 42) or OC-02 SNS (0.11 mg, 0.55 mg, or 1.1 mg; n = 41 per group) and received a single dose of study drug (100 µL using a nasal spray atomizer) at visit 1 and visit 2 (15-19 days after visit 1). Primary efficacy outcomes were change in the STS from baseline to immediately after treatment administration (visit 1) and change in the EDS from before to 5 minutes after treatment during controlled adverse environment exposure (visit 2).

FINDINGS

Baseline demographic and ocular clinical characteristics were similar across all groups. Single-dose OC-02 SNS improved the signs and symptoms of dry eye disease. For the STS, statistically significant and dose-dependent improvements were found from before to after treatment with OC-02 SNS versus vehicle (least-squares mean change from baseline: vehicle, 3.0 mm; 0.11 mg OC-02 SNS, 9.0 mm; 0.55 mg, 17.5 mm; and 1.1 mg, 19.6 mm). For EDS, statistically significant and dose-dependent improvements were found from before to 5 minutes after treatment with higher doses of OC-02 SNS versus vehicle (least-squares mean change from baseline: vehicle, -6.5; 0.11 mg OC-02 SNS, -9.4; 0.55 mg, -17.4; and 1.1 mg, -20.7). OC-02 SNS was well tolerated: only 2 ocular adverse events were reported (eye pruritis and keratitis), and the most common nonocular events were cough and throat irritation.

IMPLICATIONS

Single-dose OC-02 SNS over a range of doses immediately and significantly increased tear production and improved eye dryness. Together with previous studies of OC-01 (varenicline solution) nasal spray, our findings suggest that agonist stimulation of nAChRs in the nasal cavity is a valid and effective mechanism to elicit natural tear production in patients with dry eye disease.

CLINICALTRIALS

gov identifier: NCT03452397.

A Single Administration of OC-01 (Varenicline Solution) Nasal Spray Induces Short-Term Alterations in Conjunctival Goblet Cells in Patients with Dry Eye Disease

INTRODUCTION

Dry eye disease is characterized by a persistently unstable or deficient tear film causing discomfort or visual impairment. Varenicline is a small-molecule nicotinic acetylcholine receptor agonist recently approved for use as a preservative-free nasal spray (OC-01 [varenicline solution] nasal spray [OC-01 VNS]) to treat signs and symptoms of dry eye disease, but its effect on conjunctival goblet cells has not been studied.

METHODS

In this phase 2, single-center, vehicle-controlled study, patients aged 18 years or more with a diagnosis of dry eye disease and Ocular Surface Disease Index© score of at least 23 were randomized 2:1 to receive a 50-µL single dose of OC-01 0.06 mg VNS or vehicle nasal spray in each nostril. Image assessments for area and perimeter were performed pre and 10 min post treatment for goblet cells by in vivo confocal microscopy and for meibomian glands by infrared meibography. Non-parametric Wilcoxon signed-rank test compared pre- and post-treatment measurements for each treatment group. Treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

The study randomized 18 patients (mean age 61 years); 6 received vehicle (3/6 [50%] female) and 12 patients received OC-01 VNS (11/12 [92%] female). OC-01 VNS treatment decreased mean goblet cell area (pre-treatment, 106.4 µm2; post-treatment, 67.6 µm2; p = 0.02) and perimeter (pre-treatment, 38.9 µm; post-treatment, 31.2 µm; p = 0.03) but not vehicle did not (p = 0.25). There were no significant changes in mean meibomian gland area with either treatment (p ≥ 0.05). All TEAEs were non-ocular, non-serious, and mild.

CONCLUSIONS

This study demonstrated that a single administration of OC-01 0.06 mg VNS in patients with dry eye disease reduced conjunctival goblet cell area and perimeter, suggesting goblet cell degranulation and associated release of lubricating mucin. By activating the natural tear film, OC-01 VNS may provide benefits over topical medications.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03688802.

Nicotinic acetylcholine receptor stimulation: A new approach for stimulating tear secretion in dry eye disease

Tear secretion is regulated by the lacrimal functional unit consisting of afferent and efferent nerve innervation. The afferent arm consists of trigeminal nociceptors on the ocular surface and nasal mucosa. When stimulated by agonists, nicotinic acetylcholine receptors on nerve endings in the nose initiate a reflex arc resulting in instantaneous tear secretion. Pharmacologic nasal neural stimulation to increase endogenous tear production is a novel approach to treating dry eye disease.

Efficacy of an Intranasal Tear Neurostimulator in Sjögren Syndrome Patients

PURPOSE

To assess the efficacy and safety of an intranasal tear neurostimulator (ITN) device in Sjögren syndrome (SS) patients.

METHODS

This was a two-visit prospective, randomized, controlled, same-day crossover study in participants with SS. Inclusion criteria were assessed at a baseline screening visit and included an Ocular Surface Disease Index (OSDI) score ≥13, and a Schirmer with anesthesia ≤10 mm/5 min (in at least one eye), with a cotton swab stimulation induced increase of ≥4 mm in the same eye. Participants returned for the application visit, where they received intranasal and extranasal applications of the ITN in random sequence, separated by at least 60 min. Schirmer scores were measured in both eyes after each application and compared to baseline values. Generalized linear models were performed to compare the change in Schirmer scores from baseline, and generalized estimating equations were used to account for correlations from repeated measurements in the same eye and measurements from two eyes of the same patient.

RESULTS

Fifty-five participants were screened and 35 were enrolled (all female), ranging in age from 31 to 72 years (mean, 57 years). The baseline OSDI score ranged from 14 to 91 (mean, 50.5), and the baseline Schirmer score had a mean (SD) of 6.4 (3.5) ranging from 0 to 20 (mm/5min). Improvement in Schirmer scores was significantly greater for intranasal device application (13.5 mm/5min, 95% CI: 10.4, 16.5) compared to extranasal device application (0.8mm/5min, 95% CI: -0.9, 2.4) (p<0.0001). The effects of the intranasal device application were significant regardless of the participant's baseline Schirmer score and systemic SS medication usage (p<0.05).

CONCLUSION

Intranasal application of the ITN device significantly increased tear production in a subset of SS patients compared to baseline and was more effective than extranasal application. While production of the ITN device was recently discontinued, our findings suggest that other therapies that neurostimulate the lacrimal function unit may be effective in a subset of SS patients.

Alternative therapies for dry eye disease

PURPOSE OF REVIEW

Dry eye disease (DED) is a multifactorial disease affecting approximately 5-50% of individuals in various populations. Contributors to DED include, but are not limited to, lacrimal gland hypofunction, meibomian gland dysfunction (MGD), ocular surface inflammation, and corneal nerve dysfunction. Current DED treatments target some facets of the disease, such as ocular surface inflammation, but not all individuals experience adequate symptom relief. As such, this review focuses on alternative and adjunct approaches that are being explored to target underlying contributors to DED.

RECENT FINDINGS

Neuromodulation, stem cell treatments, and oral royal jelly have all been studied in individuals with DED and lacrimal gland hypofunction, with promising results. In individuals with MGD, devices that provide eyelid warming or intense pulsed light therapy may reduce DED symptoms and signs, as may topical Manuka honey. For those with ocular surface inflammation, naturally derived anti-inflammatory agents may be helpful, with the compound trehalose being farthest along in the process of investigation. Nerve growth factor, blood-derived products, corneal neurotization, and to a lesser degree, fatty acids have been studied in individuals with DED and neurotrophic keratitis (i.e. corneal nerve hyposensitivity). Various adjuvant therapies have been investigated in individuals with DED with neuropathic pain (i.e. corneal nerve hypersensitivity) including nerve blocks, neurostimulation, botulinum toxin, and acupuncture, although study numbers and design are generally weaker than for the other DED sub-types.

SUMMARY

Several alternatives and adjunct DED therapies are being investigated that target various aspects of disease. For many, more robust studies are required to assess their sustainability and applicability.

Use of ImageJ as an image processing method for the assessment of post-surgical bruises

PURPOSE

To develop, through ImageJ, an automated, non-invasive, objective method to analyze images of bruises that allowed quantifying variation in its size overtime for its later use in clinical trials.

METHODS

The ImageJ software was used to create automated macros that were executed on 38 images of the untreated eyes of 19 patients that participated in a post-marketing, randomized, controlled clinical trial that assessed the efficacy of a cream to reduce post-blepharoplasty minor hematomas. Three image processing systems were used with the macros created with ImageJ: RGB, RGB2, and HSB. The area of the bruises and the percentage of reduction were estimated for each one. Ophthalmologists also reviewed photographs by direct visual examination.

RESULTS

All three processing systems were useful for identifying the area of the bruise and studying its variation over time. RGB2 results were the most consistent with the direct visual examination conducted by ophthalmologists.

CONCLUSION

RGB2-automated image processing was considered the most appropriate for bruise analysis and represented an advantage over other manual techniques. However, it will be necessary to test it in clinical trials and other studies with a more significant number of samples and different locations.