[Treatment of dry eye with a new gel in eyedrop form]

Recent Advances in Nanotechnology for the Treatment of Dry Eye Disease

Dry eye disease (DED) incidence is continuously growing, positioning it to become an emergent health issue over the next few years. Several topical treatments are commonly used to treat DED; however, reports indicate that only a minor proportion of drug bioavailability is achieved by the majority of eye drops available on the market. In this context, enhancing drug ability to overcome ocular barriers and prolonging its residence time on the ocular surface represent a new challenge in the field of ocular carrier systems. Therefore, research has focused on the development of multi-functional nanosystems, such as nanoemulsions, liposomes, dendrimers, hydrogels, and other nanosized carriers. These systems are designed to improve topical drug bioavailability and efficacy and, at the same time, require fewer daily administrations, with potentially reduced side effects. This review summarizes the different nanotechnologies developed, their role in DED, and the nanotechnology-based eyedrops currently approved for DED treatment.

Dry eye syndrome: comprehensive etiologies and recent clinical trials

Dry eye syndrome (DES) is multifactorial and likely to be a cause of concern more so than ever given the rapid pace of modernization, which is directly associated with many of the extrinsic causative factors. Additionally, recent studies have also postulated novel etiologies that may provide the basis for alternative treatment methods clinically. Such insights are especially important given that current approaches to tackle DES remains suboptimal. This review will primarily cover a comprehensive list of causes that lead to DES, summarize all the upcoming and ongoing clinical trials that focuses on treating this disease as well as discuss future potential treatments that can improve inclusivity.

Timolol 0.1% in Glaucomatous Patients: Efficacy, Tolerance, and Quality of Life

Glaucoma is a progressive, chronic optic neuropathy characterized by a typical visual field defects. Four main classes of topical medication are actually available on the market: beta-blockers, prostaglandins, alpha2-agonists, and topical carbonic anhydrase inhibitor to treat intraocular pressure (IOP). The aim of this review is to outline the efficacy of timolol and to evaluate the impact of this treatment on patients' quality of life. Among beta-blockers, timolol is most used at three different concentrations: 0.1%, 0.25%, and 0.5%. While the first one is a gel, the other two products are solution. Timolol has few topical side effects, while it has some important systemic side effects on the cardiac and respiratory systems. The balance between efficacy and safety is always the main aspect to care patients. Because of the less efficacy of timolol 0.1% solution, the possibility to use carbomers as vehicle in the gel drops helped timolol 0.1 to be used in clinics, extending the time contact between the active ingredient and the surface of the cornea. Using preservative-free timolol 0.1 for treatment, IOP was at the same level of the other beta-blockers at higher concentration, but it was better tolerated. Preservative-free treatment improved the quality of life reducing dry-eye like symptoms; furthermore, the presence of an artificial tear in the medication bottle could help adherence. The once daily dosing improves compliance.

Polyacrylic Acid Gel in Patients with Dry Eyes: A Randomised Comparison with Polyvinyl Alcohol

Purpose

To compare the safety and efficacy of polyacrylic acid 0.2% (PAA) gel and polyvinylalcohol 1.4% (PVA) in the treatment of patients with dry eyes.

Methods

Eighty-nine patients with dry eyes were randomly allocated to treatment with either PAA (48) or PVA (41) in a prospective, investigator-masked study in two centres. The parameters assessed were daily frequency of instillation of the study medications, ocular signs and symptoms, tear film break up time, Schirmer's test values, local tolerance and global assessment of the improvement following treatment.

Results

The two groups were similar in patient demographics and study parameters at baseline. The total score of symptoms (gritty or foreign body sensation, burning sensation, dry eye sensation, photophobia, others) and signs (conjunctival hyperaemia, ciliary injection, corneal and conjunctival epithelial staining) was reduced significantly more by treatment with PAA than with PVA at both three and six weeks (p<0.0001). The daily frequency of instillation of PAA was significantly less than that PVA on 38 of the 41 (93%) study days. Both PAA and PVA were safe and equally well-tolerated except for blurred vision, usually mild and transient, on PAA. On global assessment of the improvement in their dry eye condition, significantly more PAA patients felt better on treatment at six (p=0.02) weeks compared with those on PVA.

Conclusions

Polyacrylic acid gel was as safe as and more effective than polyvinylalcohol in the treatment of patients with dry eyes.

Over the counter (OTC) artificial tear drops for dry eye syndrome

BACKGROUND

Over the counter (OTC) artificial tears historically have been the first line of treatment for dry eye syndrome and dry eye-related conditions like contact lens discomfort, yet currently we know little regarding the overall efficacy of individual, commercially available artificial tears. This review provides a much needed meta-analytical look at all randomized and quasi-randomized clinical trials that have analyzed head-to-head comparisons of OTC artificial tears.

OBJECTIVES

To evaluate the effectiveness and toxicity of OTC artificial tear applications in the treatment of dry eye syndrome compared with another class of OTC artificial tears, no treatment, or placebo.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2015), EMBASE (January 1980 to December 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to December 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en) and the US Food and Drugs Administration (FDA) website (www.fda.gov). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 December 2015. We searched reference lists of included trials for any additional trials not identified by the electronic searches.

SELECTION CRITERIA

This review includes randomized controlled trials with adult participants who were diagnosed with dry eye, regardless of race and gender. We included trials in which the age of participants was not reported, and clinical trials comparing OTC artificial tears with another class of OTC artificial tears, placebo, or no treatment. This review did not consider head-to-head comparisons of artificial tears with another type of dry-eye therapy.

DATA COLLECTION AND ANALYSIS

We followed the standard methodological procedures expected by Cochrane. Two authors independently screened the search results, reviewed full-text copies for eligibility, examined risk of bias, and extracted data. We performed meta-analysis for trials that compared similar interventions and reported comparable outcomes with sufficient data. We summarized all other included trial results in the text.

MAIN RESULTS

We included 43 randomized controlled trials (3497 participants with dry eye). Due to the heterogeneity of study characteristics among the included trials with respect to types of diagnostic criteria, interventions, comparisons, and measurements taken, our ability to perform meta-analyses was limited. The review found that, in general, there was uncertainty whether different OTC artificial tears provide similar relief of signs and symptoms when compared with each other or placebo. Nevertheless, we found that 0.2% polyacrylic acid-based artificial tears were consistently more effective at treating dry eye symptoms than 1.4% polyvinyl alcohol-based artificial tears in two trials assessing this comparison (175 participants). All other included artificial tears produced contradictory between-group results or found no between-group differences. Our review also found that OTC artificial tears may be generally safe, but not without adverse events. Overall, we assessed the quality of evidence as low due to high risks of bias among included trials and poor reporting of outcome measures which were insufficient for quantitative analysis. Furthermore, we identified an additional 18 potentially eligible trials that were reported only in clinical trial registers with no associated results or publications. These trials reportedly enrolled 2079 total participants for whom no data are available. Such lack of reporting of trial results represents a high risk of publication bias.

AUTHORS' CONCLUSIONS

OTC artificial tears may be safe and effective means for treating dry eye syndrome; the literature indicates that the majority of OTC artificial tears may have similar efficacies. This conclusion could be greatly skewed by the inconsistencies in study designs and inconsistencies in reporting trial results. Additional research is therefore needed before we can draw robust conclusions about the effectiveness of individual OTC artificial tear formulations.

A comparative study of polyacrylic acid (Viscotears) liquid gel versus polyvinylalcohol in the treatment of dry eyes

We conducted a prospective, randomised, single-masked study comparing the safety and efficacy of polyacrylic acid 0.2% (PAA) and polyvinylalcohol 1.4% (PVA) in 85 patients (PAA 43, PVA 42) with dry eyes. The two groups were similar in patient demographics and study parameters at baseline. With treatment, the reduction in total symptoms (gritty or foreign body sensation, burning sensation, dry eye sensation, photophobia, others) and signs (conjunctival hyperaemia, ciliary injection, corneal and conjunctival epithelial staining) score on PAA was significantly greater than that on PVA at both two and four weeks. The daily frequency of instillation of PAA was significantly less than that of PVA on 16 of the 27 (59%) study days. For overall local tolerance there was a significant preference for PAA compared to PVA by both patients and doctors. Only one patient on each treatment had an adverse event and neither was serious. PAA (Viscotears) was as safe as, but better tolerated and more effective than PVA in the treatment of dry eye conditions.

Viscous carbomer eye drops in patients with dry eyes. Efficacy and safety. A randomized, open, cross-over, multicentre study

The efficacy and safety of a new carbomer containing ocular gel was compared to a commonly used 1.4% polyvinyl alcohol-based (PVA) offificial tear preparation. Sixty-one patients with symptoms and signs of dry eyes were treated with each preparation separately for two weeks in a multicentre, randomized, open cross-over study. A statistically significant difference in favour of the new viscous carbomer eye drops compared to the PVA preparation was achieved in reducing the symptom of 'dryness', the total symptom score and in prolonging the break-up time. During the carbomer eye drops period the mean daily frequency of application was 3.92 compared to 4.64 for the PVA eye drops period (p = 0.02). Twenty-three patients (38%) reported adverse events only while using the carbomer gel and 5 (8%) only while using the PVA eye drops (p < 0.001). 'Blurred vision' was the most common adverse event reported. The present carbomer containing ocular gel may offer advantages in the treatment of dry eyes.

Diagnostic methods and treatment modalities of dry eye conditions

One may view dry eye conditions as a group of diseases in which the ocular surface is adversely affected. Tear film instability invariably leads to some degree of cellular surface damage over the cornea and conjunctiva. In turn, ocular epitheliopathy may adversely affect tear film stability. The clinical presentation of the disease may not yield a clue as to its etiology. In recent years considerable progress was made both in the diagnosis and the treatment of the disease and promising studies are planned or are underway. The diagnostic techniques can be divided into four groups. The first is concerned with the clinical presentation. The second is concerned with the bulk properties of the aqueous tears including dynamic characteristics, composition, and colligative properties. The third is tear-film related and includes the film break-up time, evaporation rate, and lipid abnormality. The fourth is concerned with the ocular surface and includes vital staining, impression cytology, and surface microscopy. The most promising attempts are being made in the second group by attempting to elucidate the role of enzyme and enzyme activator activity and inhibitor contents as well as the tear protein profiles and correlating them with the specific disease states. The treatment modalities belong to three major groups aside from surgical intervention; the supplementation, preservation, and the stimulation of tears. The modern version of tear supplementation is expected to include the topical use of efficacious aqueous formulations that typically contain film stabilizing polymers, nutrients, and/or--in the future--biochemically active ingredients such as enzyme activators and inhibitors.