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Introduction: Dry eye disease (DED) is one of the most prevalent eye conditions worldwide, with artificial tears serving as a primary treatment option. Despite their wide availability on the European market, there is a lack of established classifications based on their physicochemical properties. The aim of our study was therefore (i) to develop an analytical method that measures the concentration and the molecular weight (MW) of the hyaluronic acid (HA) in commercialized products, and (ii) to propose an overview based on their various physicochemical parameters. Methods: The intrinsic viscosity and MW of the HA, as well as osmolarity, pH, rheological profile, and viscosity, were measured or determined. A specific method was developed to measure the average intrinsic viscosity and HA content using a liquid size-exclusion chromatography system. The MW was determined using the Mark–Houwink equation. Results: Thirty-seven products commercialized in Europe were analyzed, with 21 of them containing HA. The HA MW was lowest (300 kDa) for Thealose®, Thealoz Duo® Gel, and Hyabak®, and highest (1300 kDa) for Vismed® Multi, Vismed® Gel, and Neovis® Gel. The pH values varied between 5.94 for Treovis® and 8.06 for Systane® Ultra. Osmolarity ranged between 148 mOsm/L and 325 mOsm/L for Neovis® and Treovis®, respectively. Viscosity was highly variable, ranging from 0.38 mPas·s for Hylolipid® to 337.47 mPas·s for Thealoz® Duo Gel. Finally, rheological profile analysis revealed different shear-thinning behaviors. Conclusion: While the perfect eye drop does not exist, a multitude of options are available to choose from. This study improves our understanding of the major tear substitutes available on the European market based on several physicochemical properties. A better understanding and awareness of these parameters is crucial in order to offer the best treatment for patients with DED. [ABSTRACT FROM AUTHOR]

Purpose: An innovative eyedrop formulation based on a combination of 0.2% hyaluronic acid and 0.001% hydrocortisone sodium phosphate (Idroflog®, Alfa Intes, Italy; HAC eyedrops) was granted a European Patent in 2016 and has been available on the market since 2019 in Europe and in other countries around the world. HAC eyedrops aim to synergize the moisturizing effects of hyaluronic acid with the mild anti-inflammatory properties of low-dose hydrocortisone, offering a more effective and safer alternative for treating dry eye disease (DED), targeting both tear film instability and dysfunctional para-inflammation. The activity of HAC eyedrops has been explored in different post-marketing clinical trials, in addition to preclinical studies. In this narrative review, we explored the available evidence on the use of HAC eyedrops for the management of para-inflammation in DED patients to provide a comprehensive overview of efficacy and safety data related to the use of this medical device in routine clinical practice. Methods: A literature search for preclinical and clinical data involving treatment with HAC eyedrops was conducted using PubMed/MEDLINE, considering only original research articles published in English, without time restrictions. Results: One preclinical and four clinical papers were retrieved. Preclinical evidence suggests that 0.001% hydrocortisone is able to control the expression of inflammatory markers, and this, together with the hydrating and lubricating properties of hyaluronic acid, leads to improvements in DED clinical signs, such as tear volume and the stability of the tear film. The results of clinical trials demonstrate that HAC eyedrops are able to improve the signs and symptoms of DED and that 0.001% low-dosage hydrocortisone can be helpful in preventing the progression to chronic stages of DED. Conclusions: HAC eyedrops represent a promising therapeutic strategy for the management of dysfunctional para-inflammation and offer a valuable addition to the armamentarium of treatments for DED. [ABSTRACT FROM AUTHOR]

Background: We aimed to evaluate the effects of 0.3% carboxymethylcellulose (CMC) tear substitute treatment in dry eye disease (DED), as well as treatment compliance and adverse events (AEs). Methods: In this prospective, longitudinal study, a total of 30 eyes receiving 0.3% CMC tear substitute four times daily for DED were evaluated. Clinical endpoints included an ocular surface disease index (OSDI) questionnaire, average non-invasive tear film break-up time (A-NIBUT), lipid layer thickness (LLT), and a Schirmer test with anesthesia (ST). Treatment compliance and AEs were also assessed. All evaluations were performed at 2, 4, and 12 weeks of follow-up. Results: At the end of the follow-up, significant improvement was observed in all clinical endpoints with the following mean values: ΔOSDI questionnaire of −22.53 ± 14.68 points, ΔA-NIBUT of 4.81 ± 2.88 s, ΔLLT of 5.63 ± 6.53 nm, and ΔST of 2.8 ± 2.1 mm (p < 0.001 for all comparisons). Although repeated measures analysis showed that all clinical endpoints presented statistically significant differences (p < 0.001 for all comparisons LLTBaseline–LLT2-weeks (p = 0.460) and LLT4-weeks–LLT12-weeks (p = 0.071) were the only pairs of measures that reported non-statistically significant differences). In addition, treatment compliance was 94.3 ± 5.2% and transient AEs related to the use of 0.3% CMC tear substitute were reported. Conclusions: 0.3% CMC tear substitute treatment seems to achieve beneficial effects on the OSDI questionnaire, A-NIBUT, LLT, and ST. However, further studies at this concentration are needed to confirm these results. [ABSTRACT FROM AUTHOR]

Dry eye disease (DED) is the most common ocular surface disease, characterized by insufficient production and/or instability of the tear film. Tear substitutes are usually the first line of treatment for patients with DED. Despite the large variety of tear substitutes available on the market, few studies have been performed to compare their performance. There is a need to better understand the specific mechanical and pharmacological roles of each ingredient composing the different formulations. In this review, we describe the main categories of ingredients composing tear substitutes (e.g., viscosity-enhancing agents, electrolytes, osmo-protectants, antioxidants, lipids, surfactants and preservatives) as well as their effects on the ocular surface, and we provide insight into how certain components of tear substitutes may promote corneal wound healing, and/or counteract inflammation. Based on these considerations, we propose an approach to select the most appropriate tear substitute formulations according to the predominant etiological causes of DED. [ABSTRACT FROM AUTHOR]

The purpose of this prospective study was to evaluate the efficacy of the perioperative use of a hyaluronic acid (HA) and trehalose ophthalmic solution (Thealoz® Duo) in reducing post-cataract surgery dry eye signs and symptoms in patients with mild/moderate dry eye disease (DED). One hundred and twenty patients, scheduled for unilateral cataract surgery, were randomized into three groups: (1) group A: HA/trehalose three times/day in the preoperative week and for 5 postoperative weeks; (2) group B: HA/trehalose for only 5 postoperative weeks; (3) group C: no artificial tears. In groups A and B, OSDI (Ocular Surface Disease Index) questionnaire scores were significantly lower than group C at all the postoperative visits; in group A they were significantly lower than group B on the day of surgery, with similar results in the first and fifth weeks after surgery. In groups A and B, break-up time (BUT) was significantly higher than group C during the postoperative period (p ≤ 0.001). In comparison to the preoperative values, BUT in group A remained stable 7 days after surgery; however, in groups B and C, it significantly decreased. In conclusion, the HA/trehalose ophthalmic solution effectively reduced post-cataract surgery DED signs and symptoms in patients with mild/moderate DED, particularly if also administered in the preoperative period. [ABSTRACT FROM AUTHOR]