Efficacy of hypotonic 0.18% sodium hyaluronate eye drops in patients with dry eye disease

Tear film stability in patients with symptoms of dry eye after instillation of dual polymer hydroxypropyl guar/sodium hyaluronate vs single polymer sodium hyaluronate

PURPOSE

This study evaluated the tear film stability in patients with symptoms of dry eye after installation of dual polymer hydroxypropyl guar/sodium hyaluronate (DPHG/SH) vs single polymer SH.

METHODS

Patients with recently diagnosed mild to moderate dry eye disease (OSDI score 23-32 points) were included. For each patient, the right eye was randomized to receive DPHG/SH or 0.15% SH. Just after the administration of the drop to the right eye, the fellow eye received the other eye drop. The first non-invasive Keratograph first break-up time (NIKBUT), average NIKBUT and tear meniscus height (TMH) were measured before administration of the eye drops, at 1-min, 15 min, 30 min, 60 min, 90 min, and 120 min after instillation.

RESULTS

A total of 29 patients aged 22.8 ± 2.2 years participated in the study (21 women). No differences between the eye receiving DPHG/SH and single polymer SH were observed for the first NIKBUT (p = 0.45) and average NIKBUT (p = 0.24) variables at any time point. Both DPHG/SH and single polymer SH increased the TMH (p of time effect < 0.001), but with no difference between groups (p = 0.95).

CONCLUSION

Both DPHG/SH and single polymer SH solutions provide lubrication of the eye surface, however, with no difference in NIKBUT and TMH evaluations for up to two hours following administration.

Short-term changes in tear osmolarity after instillation of different osmolarity eye drops in patients with dry eye

This study investigated short-term changes in tear osmolarity of dry eye patients after using artificial tears containing sodium hyaluronate (SH) at different osmolarities. It comprised 80 patients with dry eye whose tear osmolarity measurement using the TearLab osmolarity system was 300 mOsm/L or greater. Patients who had external ocular disease, glaucoma, or other concomitant ocular pathology were excluded. After being randomly divided into four groups, the participants received different kinds of SH eye drops as follows: Groups 1-3 were given one of three concentrations (0.1%, 0.15%, and 0.3%) of isotonic drops, while Group 4 received 0.18% hypotonic SH eye drops. The tear osmolarity concentrations were evaluated at baseline and again at 1-, 5-, and 10-min after instillation of each eye drop. Tear osmolarity showed a significant decrease after instillation of four types of SH eye drops after up to 10 min compared to baseline. Patients who received hypotonic SH eye drops showed an enhanced decrease in tear osmolarity compared with the isotonic SH eye drops after 1 min (p < 0.001) and 5 min (p = 0.006), but the difference was not significant at 10 min (p = 0.836). The enhanced immediate effect of hypotonic SH eye drops at lowering tear osmolarity in patients with dry eye seems to be limited unless these drops were used frequently.

Improving Visual Comfort during Computer Gaming with Preservative-Free Hyaluronic Acid Artificial Tears Added to Ergophthalmological Measures

Digital asthenopia (DA) or Computer Vision Syndrome can occur after prolonged use of digital devices and is usually managed with ergophthalmological measures and the use of artificial tears. This prospective, controlled study evaluated the use of hyaluronic acid artificial tears on the signs and symptoms of DA in participants of a videogame convention. Subjects (n = 56) were randomized into a control group (CG, n = 26), which followed ergophthalmological measures, and a study group (SG, n = 30), which followed ergophthalmological measures and instilled 1 drop of artificial tears with hyaluronic acid 0.15% four times a day. Subjects were evaluated before and after playing for three consecutive days for eye dryness (SPEED questionnaire), conjunctival hyperemia, corneal fluorescein staining, conjunctival lissamine green staining, tear breakup time, Schirmer I test, near convergence and accommodation, and using questionnaires for DA symptoms. After 3 days of intense videogaming, the SPEED score of CG increased significantly (p = 0.0320), while for the SG it was unchanged. Similarly, the CG presented significant increases in ocular fatigue (p = 0.0173) and dryness (p = 0.0463), while these parameters decreased significantly in the SG (p = 0.0149 and p = 0.00427, respectively). This study confirms the protective effect of hyaluronic acid artificial tears against DA symptoms associated with prolonged visual display terminal use.

Hyaluronic acid in the treatment of dry eye disease

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.

A randomized multicenter clinical evaluation of sequential application of 0.3% and 0.15% hyaluronic acid for treatment of dry eye

PURPOSE

We report the clinical efficacy of sequential applications of 0.3% and 0.15% unpreserved hyaluronic acid (HA) for the treatment of dry eye disease (DED).

STUDY DESIGN

Randomized clinical trial.

METHODS

Patients over 19 years of age with DED level 2 or higher, corneal fluorescein staining (CFS) score > 1, and tear break-up time (TBUT) < 10 s were included. Seventy-six patients were randomly assigned to the 0.15% HA group, 0.3% HA group, or combination group. Each group applied two drops of 0.15% or 0.3% HA, or a single drop of both 0.3% and 0.15% HA. Patients were evaluated using the ocular surface disease index (OSDI), CFS and conjunctival fluorescein stain score, TBUT, and blurring/discomfort after application at baseline, 4 weeks, and 8 weeks.

RESULTS

The combination group had the greatest improvement in CFS score from baseline to 8 weeks, compared with the 0.15% and 0.3% HA group (p < 0.001). The combined CFS-OSDI responder rates of the combination group (CFS score = 0 and OSDI ≥ 50% improvement at 8 weeks) were significantly higher than those of the 0.15% and 0.3% groups (p = 0.037). At 4 and 8 weeks, blurring after application in both the 0.3% and combination groups was significantly higher than in the 0.15% group, despite no difference between the 0.3% and combination groups. There were no differences in CFS and conjunctival staining score, TBUT, or OSDI within the three groups at baseline, 4 weeks, and 8 weeks.

CONCLUSIONS

Sequential application of 0.3% and 0.15% HA improved symptoms/signs in moderate to severe DED patients.

A Sensitive Chromatographic Method for Hyaluronate Quantification Applied to Analyze the Desorption Behavior on Contact Lenses

Background:

Sodium hyaluronate (NaHA) is generally supplemented in products related to contact lenses for increasing comfort during wearing. The quantity of sodium hyaluronate and the material of lenses affect the retention of sodium hyaluronate on the contact lenses.

Methods:

We developed a convenient and sensitive but unconventional chromatographic method to quantify sodium hyaluronate and analyze its release behavior from contact lenses. The reverse-phase chromatography eluted sodium hyaluronate with high molecular masses in the shortest time and could separate salt and small compounds from sodium hyaluronate.

Results:

This method could accurately quantify sodium hyaluronate with diverse molecular sizes. Because sodium hyaluronate was eluted in a narrow time frame, sensitivity was significantly enhanced, and the limit of detection of this method was 0.45 μg/mL. According to this quantitation method, the attached quantity of sodium hyaluronate is related to the water content of the material. Furthermore, a material test indicated that the release efficiency of sodium hyaluronate depends on the material of lenses. Nonionic Polymacon had a longer half-life in the sodium hyaluronate release curve than negative Methafilcon A and silicone hydrogel.

Conclusion:

This hyaluronate quantification method is a fast, sensitive and accurate method, making it suitable for the in vitro hyaluronate research without further derivatization.

Topical cyclosporine A therapy for dry eye syndrome

BACKGROUND

Topical cyclosporine A (also known as ciclosporin A) (CsA) is an anti-inflammatory that has been widely used to treat inflammatory ocular surface diseases. Two CsA eyedrops have been approved by US Food and Drug Administration for managing dry eye: Restasis (CsA 0.05%, Allergan Inc, Irvine, CA, USA), approved in 2002, and Cequa (CsA 0.09%, Sun Pharma, Cranbury, NJ, USA), approved in 2018. Numerous clinical trials have been performed to assess the effectiveness and safety of CsA for dry eye; however, there is no universal consensus with regard to its effect.

OBJECTIVES

To assess the effectiveness and safety of topical CsA in the treatment of dry eye.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 2); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 16 February 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of people with dry eye regardless of age, sex, severity, etiology, or classification of dry eye. We included RCTs in which different concentrations of topical CsA were compared with one another or with artificial tears, placebo, or vehicle. We also included RCTs in which CsA in combination with artificial tears was compared to artificial tears alone.

DATA COLLECTION AND ANALYSIS

We followed the standard Cochrane methodology and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 30 RCTs (4009 participants) with follow-up periods ranging from 6 weeks to 12 months. We studied dry eye of various severity and underlying causes. The interventions investigated also varied across RCTs: CsA versus artificial tears; CsA with artificial tears versus artificial tears alone; and in some studies, more than one concentration of CsA. Artificial tears were used as adjunctive to study medication in all but five trials. Almost all trials had deficiencies in the reporting of results (e.g. reporting P values or direction only), precluding the calculation of between-group estimates of effect or meta-analysis.Eighteen trials compared topical CsA 0.05% plus artificial tears versus vehicle plus artificial tears or artificial tears alone. One trial reported subjective symptoms of dry eye at 6 months and the results were in favor of CsA (mean difference (MD) -4.80, 95% confidence interval (CI) -6.41 to -3.19; low-certainty evidence). Two trials reported MD in ocular surface dye staining at 6 months, but the results were inconsistent in these two trials (MD -0.35, 95% CI -0.69 to -0.01 in one and MD 0.58, 95% CI 0.06 to 1.10 in the other; low-certainty evidence). Four trials reported MD in Schirmer test scores at 6 months and the estimates ranged from -4.05 (95% CI -6.67 to -1.73) to 3.26 (95% CI -1.52 to 5.00) (low-certainty evidence). Three trials reported risk ratio (RR) of improved Schirmer test scores at 6 months; estimates ranged from 0.98 (95% CI 0.83 to 1.17) to 3.50 (95% CI 2.09 to 5.85) (low-certainty evidence). Four trials reported MD in tear film stability measured by tear break-up time at 6 months and the estimates ranged from -1.98 (95% CI -3.59 to -0.37) to 1.90 (95% CI 1.44 to 2.36) (low-certainty evidence). Three trials reported RR of improved tear break-up time at 6 months and the estimates ranged from 0.90 (95% CI 0.77 to 1.04) to 4.00 (95% CI 2.25 to 7.12) (low-certainty evidence). Three trials reported frequency of artificial tear usage at 6 months without providing any estimates of effect; the direction of effect seem to be in favor of CsA (low-certainty evidence). Because of incomplete reporting of the results data or considerable statistical heterogeneity, we were only able to perform a meta-analysis on mean conjunctival goblet cell density. Mean conjunctival goblet cell density in the CsA treated group may be greater than that in the control group at the end of follow-up at four and 12 months (MD 22.5 cells per unit, 95% CI 16.3 to 28.8; low-certainty evidence). All but two trials reported adverse events that included burning and stinging. Participants treated with CsA may be more likely to have treatment-related adverse events than those who treated with vehicle (RR 1.33, 95% CI 1.00 to 1.78; low-certainty evidence).Other comparisons evaluated were CsA 0.05% plus artificial tears versus higher concentrations of CsA plus artificial tears (4 trials); CsA 0.05% versus placebo or vehicle (4 trials); CsA 0.1% plus artificial tears versus placebo or vehicle plus artificial tears (2 trials);CsA 0.1% cationic emulsion plus artificial tears versus vehicle plus artificial tears (2 trials); CsA 1% plus artificial tears versus placebo plus artificial tears (3 trials); and CsA 2% plus artificial tears versus placebo plus artificial tears (3 trials). Almost all of these trials reported P value or direction of effect only (mostly in favor of CsA), precluding calculation of between-group effect estimates or meta-analyses.

AUTHORS' CONCLUSIONS

Despite the widespread use of topical CsA to treat dry eye, we found that evidence on the effect of CsA on ocular discomfort and ocular surface and tear film parameters such as corneal fluorescein staining, Schirmer's test, and TBUT is inconsistent and sometimes may not be different from vehicle or artificial tears for the time periods reported in the trials. There may be an increase in non-serious, treatment-related adverse effects (particularly burning) in the CsA group. Topical CsA may increase the number of conjunctival goblet cells. However, current evidence does not support that improvements in conjunctival mucus production (through increased conjunctival goblet cells) translate to improved symptoms or ocular surface and tear film parameters. All published trials were short term and did not assess whether CsA has longer-term disease-modifying effects. Well-planned, long-term, large clinical trials are needed to better assess CsA on long-term dry eye-modifying effects. A core outcome set, which ideally includes both biomarkers and patient-reported outcomes in the field of dry eye, is needed.

Comparison Between Viscous Teardrops and Saline Solution to Fill Orthokeratology Contact Lenses Before Overnight Wear

OBJECTIVE

To compare, in terms of efficacy, the differences between the use of saline solution and a viscous artificial tear to fill the lens during the first month of orthokeratology wear.

METHODS

A pilot, double-masked, crossed, randomized, and prospective study was conducted. In this study, 20 subjects (14 males and 6 females) with a mean age of 16.29±6.22 years (range, 10-26) were fitted with orthokeratology contact lenses. For the study, nonpreserved 0.9% NaCl commercial saline solution (Avizor, Madrid, Spain) and nonpreserved artificial teardrops with 0.3% of hyaluronic acid (Ocudry 0.3%; Avizor, Madrid, Spain) were used. Corneal staining, tear break up time (TBUT), topography, refraction, visual acuity, and subjective comfort and vision with the visual analog scale (score from 0 to 10, being 10 better comfort and vision) were evaluated at 1 day, 1 week, and 1 month of contact lens wear.

RESULTS

The corneal staining was statistically greater in the saline group than in the Ocudry group for the first day and during 1 week of wear (P<0.05). Comfort was found to be statistically better, with Ocudry 0.3% than saline solution, being 7.17±1.94 and 6.37±1.63, for the first day, and 8.78±0.43 and 8.15±0.62 for the day 28, respectively (P<0.05). However, no differences were found for subjective vision scores, TBUT, spherical equivalent, best-corrected visual acuity and uncorrected visual acuity, and mean keratometry between groups for any visit (P>0.05).

CONCLUSION

Viscous artificial tears improve the subjective comfort of patients and reduce the corneal staining, compared with saline solution during the orthokeratology lenses fitting process. However, no differences between solutions for the treatment efficacy, in vision and corneal topography, were found.

Development of In Vitro Methodologies to Investigate Binding by Sodium Hyaluronate in Eye Drops to Corneal Surfaces

PURPOSE

To develop in vitro methods to assess binding by sodium hyaluronate in eye drops to corneal surfaces.

METHODS

Two different, complementary corneal binding set-ups were developed. In a dynamic in vitro model, confluent corneal epithelial cells (HCE-T) were assembled in chamber slides and a declining channel. A static model was constructed with ex vivo porcine corneas clamped in Franz cells. To test the predictive capacity of models, four different eye drops containing sodium hyaluronate were spiked with tritium-labeled sodium hyaluronate to standardize quantification. In both settings, eye drops were applied for 5 min and physiological conditions were mimicked by flushing with artificial tear fluid. Spreading experiments on HCE-T next to synthetic membranes were used for further characterization.

RESULTS

Binding was more pronounced in dynamic HCE-T model. Three of the four eye drops demonstrated sigmoidal elution of sodium hyaluronate, suggesting pronounced binding. One solution eluted distinctly faster, likewise the buffer control. The static method produced a similar ranking but at lower levels. When eye drops in which phosphate buffer was replaced by citrate buffer (i.e., to prevent calcification) were used, binding was not influenced. All eye drops spread immediately when placed on HCE-T and at the same order of magnitude on glass and polyethylene terephthalate surfaces.

CONCLUSION

Dynamic and static models performed on different corneal sources were used to determine sodium hyaluronate binding kinetics in solutions under physiological conditions. These methodologies resulted in a ranking of the capacity of sodium hyaluronate to bind in vitro to corneal surfaces.

Comparison of 0.1%, 0.18%, and 0.3% Hyaluronic Acid Eye Drops in the Treatment of Experimental Dry Eye

PURPOSE

To compare the efficacy of 0.1%, 0.18%, and 0.3% hyaluronic acid (HA) artificial tear in the treatment of experimental dry eye (EDE).

METHODS

EDE was established in female C57BL/6 mice through an air draft and subcutaneous scopolamine injection. The mice were divided into 5 groups according to topical treatment regimens (n = 5 each): EDE control, balanced salt solution (BSS), preservative-free 0.1% HA, 0.18% HA, and 0.3% HA. The tear film break-up time (TBUT) and corneal fluorescein staining scores were measured 5, 10, 14, 21, and 28 days after treatment. The corneal smoothness scores were measured. In addition, periodic acid-Schiff (PAS) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed.

RESULTS

The values for TBUT and corneal fluorescein staining showed greater improvements in all the HA groups (P < 0.05) than in the EDE and BSS groups after 10 days of treatment. Mice treated with 0.3% HA showed a more significant improvement in all clinical parameters than did those in the EDE control, BSS, 0.1% HA, and 0.18% HA groups (all P < 0.05) after 28 days of treatment. The goblet cell counts were higher in the 0.3% and 0.18% HA groups than in the 0.1% HA group. The number of TUNEL-positive cells was the lowest in the 0.3% HA group.

CONCLUSIONS

In EDE, 0.3% HA artificial tears are more effective than the 0.1% and 0.18% HA in improving tear film instability and ocular surface staining and irregularity, in increasing the number of conjunctival goblet cells, and in decreasing corneal epithelial apoptosis.

Effect of diquafosol tetrasodium 3% on the conjunctival surface and clinical findings after cataract surgery in patients with dry eye

PURPOSE

To investigate the effects of diquafosol tetrasodium (DT) 3% on conjunctival impression cytologic findings in addition to clinical symptoms and signs after cataract surgery in patients with preexisting dry eye disease (DED).

METHODS

Ninety-four eyes of 94 patients with DED who underwent uneventful cataract surgery were included. In total, 50 patients were treated with DT 3% (group A), while 44 patients were treated with sodium hyaluronate 0.1% (group B) postoperatively, along with topical antibiotics and steroids. Conjunctival impression cytology was performed at baseline and at 4 and 12 weeks after surgery. Visual acuity, ocular surface disease index (OSDI), tear film breakup time (TBUT), keratoepitheliopathy score, Schirmer's test, and tear clearance rate were measured at baseline and at 1, 4, and 12 weeks, and corneal aberration was analyzed at baseline and at 4 and 12 weeks.

RESULTS

The grade of conjunctival squamous metaplasia was lower at 12 weeks, and goblet cell density was higher at 4 and 12 weeks in group A than in group B (P < 0.05). Compared with group B, group A showed significantly lower OSDI scores at 4 and 12 weeks, longer TBUT at 1, 4, and 12 weeks, lower keratoepitheliopathy scores at 1 and 12 weeks, and lower total root-mean-square score and spherical aberrations at 4 weeks after surgery (P < 0.05).

CONCLUSIONS

DT 3% eye drops application after cataract surgery was effective in improving conjunctival epithelial morphology and goblet cell density as well as clinical findings in patients with DED.

Efficacy and Safety of 0.2% Hyaluronic Acid in the Management of Dry Eye Disease

OBJECTIVES

To evaluate the safety and efficacy of a new artificial tear containing 0.2% hyaluronic acid, as compared with 0.9% saline solution, in mild dry eye patients after 1-month use in a crossover study design with washout periods.

METHODS

Overall, 16 mild dry eye patients were included. After a week of washout, every patient used the experimental product (Visaid 0.2%) and the control product (0.9% saline solution), each for a month (3-8 drops daily). Both products were preservative free. The percentage change for the following variables were calculated and analyzed: Ocular Surface Disease Index (OSDI) questionnaire, visual acuity, intraocular pressure, ophthalmoscopy evaluation, biomicroscopy findings, fluorescein corneal staining and lissamine green conjunctival staining, tear breakup time, contrast sensitivity, Schirmer's test, and subject satisfaction.

RESULTS

Patients reported an improvement (a significant decrease of -19.5%±27.5%) in OSDI scores after using Visaid 0.2% and a worsening (a significant increase of 19.2%±32.4%) after using 0.9% saline solution; the difference was significant (P=0.0087, Student's t test). Significant changes (P≤0.04, Wilcoxon's test) were found comparing Visaid 0.2% with saline solution for bulbar hyperemia (-39.1%±50.8% vs. 7.8%±12.0%, respectively), corneal staining (-26.0%±53.0% vs. 36.5%±73.3%), conjunctival staining (-54.7%±53.4% vs. -7.8%±47.2%), and subjective satisfaction (26.8%±28.5% vs. -13.3%±22.5%). There were no significant differences in the safety parameters for either solution.

CONCLUSION

This clinical trial demonstrates the safety of Visaid 0.2% and its clear benefit over 0.9% saline solution.

Comparison of 0.3% Hypotonic and Isotonic Sodium Hyaluronate Eye Drops in the Treatment of Experimental Dry Eye

PURPOSE

To compare the efficacy of 0.3% hypotonic and isotonic sodium hyaluronate (SH) eye drops in the treatment of experimental dry eye.

METHODS

Experimental dry eye was established in female C57BL/6 mice by subcutaneous scopolamine injection and an air draft. The mice were divided into three groups (n = 15): control, preservative-free 0.3% isotonic SH, and preservative-free 0.3% hypotonic SH. The tear volume, tear film break-up time, and corneal fluorescein staining scores were measured 5 and 10 days after treatment. After conjunctival tissues were excised at 10 days, the levels of interleukin (IL)-6, IL-17, interferon (IFN)-γ, and IFN-γ inducible protein-10 were determined using the multiplex immunobead assay. In addition, PAS staining and flow cytometry were performed to evaluate the counts of conjunctival goblet cells and CD4+ IFN-γ+ T cells.

RESULTS

Mice treated with 0.3% hypotonic SH showed a significant decrease in corneal staining scores (P = 0.04) and the levels of IL-6 (16.7 ± 1.4 pg/mL, P = 0.02) and IFN-γ (46.5 ± 11.5 pg/mL, P = 0.02) compared to mice treated with 0.3% isotonic SH (IL-6; 32.5 ± 8.8 pg/mL, IFN-γ; 92.0 ± 16.0 pg/mL) at day 10. Although no significant difference in CD4+ IFN-γ+ T cell numbers was observed, goblet cell counts were higher in the hyopotonic SH group than in the isotonic SH group (P = 0.02).

CONCLUSIONS

When compared to 0.3% isotonic SH eye drops, 0.3% hypotonic SH eye drops can be more effective by improving corneal staining scores, decreasing inflammatory molecules, and increasing goblet cell counts for experimental dry eye. These data suggest that hypotonic artificial tears may be useful as an adjunctive treatment for inflammatory dry eye.

Hyaluronan as a promising excipient for ocular drug delivery

Hyaluronan (HA) is a naturally occurring polysaccharide and well known for its exceptional properties such as high biocompatibility and biodegradability, along with a low immunogenicity. Besides its use for various biomedical applications it recently came into focus as a favorable excipient for the formulation of various ocular therapeutics. This review article summarizes the ocular distribution of HA and its most heavily investigated binding protein "cluster of differentiation 44" (CD44) which is the rationale for the clinical use of HA, primarily as an additive in ocular applications ranging from eye drops to contact lenses. Moreover, examples will be given for using HA in various pre-clinical approaches to generate entirely new therapeutics, most notably in the field of nanotechnology.

Increased concentration of hyaluronan in tears after soaking contact lenses in Biotrue multipurpose solution

Purpose

This study was conducted to determine 1) the concentration of hyaluronan (HA) in the tear films of contact lens (CL) wearers versus non-CL wearers and 2) whether HA sorbed from Biotrue, an HA-containing multipurpose solution (MPS), onto senofilcon A lenses affects the concentration of HA in tears after 2 hours of wear.

Patients and methods

Tears of habitual CL wearers and non-CL wearers were collected on Schirmer strips at baseline and after 2 hours of wear of senofilcon A CLs that had first been either rinsed with Sensitive Eyes Saline or soaked in Biotrue MPS for 14 hours. HA concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and adjusted for sample volumes.

Results

No difference in baseline concentrations of HA in tears was found between CL wearers and non-CL wearers (P=0.07), nor between males and females (P=0.06). However, age was significantly negatively associated with HA concentration (P<0.01), and mostly, CL wear contributed to a significant association (P<0.01). Among saline-rinsed CL wearers, no change in HA concentration in tears was observed after 2 hours of wear (P=0.38). By contrast, a significant increase in HA concentration was observed in the tears from eyes that had worn CLs soaked in Biotrue MPS when compared to baseline (P=0.01) or to saline-rinsed control (P=0.03).

Conclusion

1) In this study population, no difference in baseline concentration of HA was observed between CL wearers and non-CL wearers, and 2) after 2 hours of wear of senofilcon A lenses that were soaked in Biotrue MPS, HA concentrations in the tear films of CL wearers increased.

Sodium hyaluronate's effect on xerophthalmia: a meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Several studies in the past have attempted to demonstrate the efficacy of sodium hyaluronate in the treatment of xerophthalmia. However, results have been conflicting and a definite conclusion has not yet been reached. In order to provide integrated evidence for the effectiveness of sodium hyaluronate and to judge the methodological value of relevant randomized controlled trials (RCTs) in nearly thirty years, we conducted this meta-analysis.

METHODS

A range of electronic databases were searched: MEDLINE, the Cochrane Library Database, EMBASE, CINAHL, Web of Science and the Chinese Biomedical Database (CBM) without language restrictions. Two independent reviewers assessed trials for eligibility and quality, and meta-analysis was performed using the STATA 12.0 software. An integrated odds ratio (OR) with its corresponding 95% confidence interval (95% CI) was calculated.

RESULTS

Six RCTs were included with a total of 839 xerophthalmia patients. The meta-analysis results revealed that patients with xerophthalmia who received the intervention of sodium hyaluronate eye drops didn't have significantly higher remission rate of dry eye symptoms than those in controlled groups (OR = 1.811, 95% CI = 0.741-4.429, p = 0.193). Sensitivity analysis suggested that the statistical results were robust. No publication bias was detected in this meta-analysis (p > 0.05).

CONCLUSION

Although sodium hyaluronate can be used to help relieve the symptoms of dry eyes, present evidence cannot show in unequivocal terms that patients with xerophthalmia can benefit more from the clinical application of sodium hyaluronate than other eye drops or therapies.

Development of novel mucoadhesive hyaluronic acid derivate as lubricant for the treatment of dry eye syndrome

Background: Dry eye – a disease affecting between 4 and 34% of the population worldwide. Stressful conditions to ocular surface, contact lenses as well as systemic disease cause dry eye. Novel synthesized hyaluronic acid derivate was evaluated in terms of its potential as mucoadhesive and lubricant. Results & methodology: Hyaluronic acid was chemically modified with cysteine ethyl ester (hyaluronic acid-cysteine ethyl ester). Mucoadhesion, disintegration and water uptake capacity, moreover, safety as the hen's egg test for mucous membrane compatibility were evaluated. According to the results, hyaluronic acid-cysteine ethyl ester achieved 3.81-fold increased swelling capacity, 30.5-fold more improvement mucoadhesive properties and 9.72-fold higher stability of hyaluronic acid, which was achieved due to the chemical modification. Summary: Thus, the promising results underpin further exploitation of this versatile polysaccharide for treating dry eye syndrome.