Improvement of Soft Contact Lens Wettability After the Instillation of Hyaluronic Acid Eye Drops.

PURPOSE: To evaluate the effect of the topical instillation of hyaluronic acid eye drops with different viscosity on soft contact lens wettability and comfort. METHODS: A randomized and participant-masked study was performed, involving 20 participants (25.4±2.6 years). One eye wore hydrogel (ocufilcon D) contact lenses, and another eye wore silicone-hydrogel (somofilcon A) contact lenses. The in vivo wettability tear film surface quality (TFSQ) index and comfort were measured before and after the instillation of different eye drops: saline solution (control) and 0.1%, 0.2%, and 0.3% hyaluronic acid. RESULTS: Compared with saline solution, the instillation of 0.1%, 0.2%, and 0.3% hyaluronic acid improved the in vivo wettability of the hydrogel contact lenses by decreasing their TFSQ mean for 5, 10, and 30 min, respectively ( P <0.05). During silicone-hydrogel contact lens wear, the hyaluronic acid did not affect wettability because there were no changes in TFSQ mean ( P ≥0.05), but the 0.3% hyaluronic acid produced a decrease in comfort for the first 3 min ( P <0.05). CONCLUSIONS: The instillation of hyaluronic acid eye drops increased the in vivo wettability of the hydrogel contact lens, and the duration of this effect was directly related to its concentration and viscosity.

Stabilization of comfort and visual quality after the insertion of soft contact lenses.

PURPOSE: To evaluate comfort, visual function, and in vivo wettability after the insertion of hydrogel and silicone hydrogel contact lenses for a better understanding of how long practitioners should wait for the initial evaluation of soft contact lenses. METHODS: A short-term prospective, contralateral, randomized, and participant-masked study was carried out. Twenty healthy participants (25.4 ± 2.6 years) were evaluated after the insertion of two different soft contact lenses at different times (1, 5, 10, 20, 30 min). Ocufilcon D (hydrogel) and Somofilcon A (silicone hydrogel) contact lenses were randomly assigned to both eyes of the same participant. Comfort, visual function under photopic conditions in terms of high-contrast visual acuity, low-contrast visual acuity, contrast sensitivity, and in vivo wettability were measured. RESULTS: There was an increase in comfort (p < 0.001), high-contrast visual acuity (p < 0.05), and contrast sensitivity (p < 0.001, only with silicone hydrogel) directly related to time after contact lens insertion. Besides, in vivo wettability suffered a statistically significant deterioration directly related to time with both contact lenses (p < 0.05). Except for comfort and contrast sensitivity, all the parameters stabilized their values 10 min after the insertion of both soft contact lenses. Additionally, in vivo wettability and visual acuity differences were found between hydrogel and silicone hydrogel contact lenses (p < 0.05). CONCLUSIONS: It would be possible to properly evaluate high-contrast visual acuity, low-contrast visual acuity, and in vivo wettability 10 min after the insertion of both soft contact lenses.

Efficacy of Artificial Tears Based on an Extract of Artemia salina Containing Dinucleotides in a Rabbit Dry Eye Model.

(1) Background: Artemia salina is a brine shrimp containing high concentrations of dinucleotides, molecules with properties for dry eye treatment. For this reason, the purpose of the study was to evaluate the effect of the artificial tears based on an extract of Artemia salina in a rabbit dry eye model. (2) Methods: A prospective and randomized study was carried out. Twenty rabbits were divided into 4 groups (n = 5, each group): healthy rabbits, dry eye rabbits, dry eye rabbits treated with hypromellose (HPMC), and dry eye rabbits treated with Artemia salina. Dry eye was induced by the topical instillation of 0.2% benzalkonium chloride. The measurements were performed before and after the treatment for 5 consecutive days. (3) Results: The topical instillation of artificial tears containing Artemia salina showed beneficial effects on tear secretion, tear break-up time, corneal staining, the density of Goblet cells, heigh of mucin cloud secreted by these cells, and mRNA levels of IL-1ß and MMP9 in conjunctival cells. Compared with the HPMC, there was a statistically significant improvement (p < 0.05) with the Artemia salina in all the variables under study, except for the conjunctival hyperemia, density of Goblet cells, and mRNA levels of IL-6. (4) Conclusions: The potential of artificial tears based on Artemia salina as a secretagogue agent for dry eye treatment was confirmed, opening the door for future clinical trials and studies to extrapolate the findings for dry eye patients.

Changes in visual quality with soft contact lenses after the instillation of hyaluronic acid eye drops.

PURPOSE: To evaluate the changes in visual function and anterior surface aberrations during soft contact lens (SCL) wear after the instillation of hyaluronic acid (HA) eye drops with different viscosity. METHODS: A prospective, randomized, and participant-masked study was performed. Twenty healthy participants (25.4 ± 2.6 years) were evaluated. Hydrogel (Ocufilcon D) and silicone-hydrogel (Somofilcon A) SCL were randomly assigned to both eyes of the same participant. Visual function in terms of high- and low-contrast corrected distance visual acuity (CDVA) and anterior contact lens surface aberrations (RMS HOA) were measured before and after the instillation, at different times, of different eye drops: saline (control) and 0.1%, 0.2%, and 0.3% HA. RESULTS: Compared with the saline solution, during hydrogel SCL wear, there was an improvement (P < 0.05) in high-contrast CDVA after 3 and 10 min with 0.1% HA, and after 5 and 20 min with 0.2% HA. During silicone-hydrogel SCL wear, there was a deterioration (P < 0.05) in high-contrast CDVA after 1 and 30 min with 0.3% HA. Additionally, during silicone-hydrogel SCL wear, there was also a deterioration (P < 0.05) in low-contrast CDVA after 5 and 20 min with 0.3% HA. In terms of RMS HOA, there were no clinically relevant changes with both SCL. CONCLUSIONS: The instillation of HA eye drops could have a different effect on visual quality depending on their concentration of HA, the contact lens material, its surface ionicity, or other physicochemical properties that should be studied in future studies.

Preclinical Development of Artificial Tears Based on an Extract of Artemia Salina Containing Dinucleotides in Rabbits.

PURPOSE: To evaluate the preclinical efficacy of eye drops based on an extract of Artemia salina on the ocular surface of rabbits. Tear secretion, tear break-up time and corneal staining were measured. MATERIAL AND METHODS: A preclinical and short-term prospective study was performed. Twenty New Zealand white rabbits were divided into five groups, with four rabbits per group, each receiving a different concentration of Artemia salina. In each rabbit, an extract of Artemia salina (2%, 4%, 6%, 8% or 10%) was randomly instilled in one eye and saline solution (negative control) in the other eye. Tear secretion, tear break-up time and corneal staining were measured before and after the instillation of five drops per eye (one drop per hour) on the same day. RESULTS: In tear secretion, there was an increase of 43.88 ± 6.73% with 4% Artemia salina in comparison with its baseline measurement (P = .049). The rest of the groups did not show differences (P ≥ 0.05). For tear break-up time, none of the groups showed differences (P ≥ 0.05), while for corneal staining score, there was an improvement of 0.88 ± 0.83 with 4% Artemia salina (P = .038) and a deterioration of 0.50 ± 0.83 with control solution (P = .008). CONCLUSIONS: Short-term instillation of eye drops with 4% Artemia salina produced both stimulation of tear secretion and a slight improvement of physiological corneal staining. Besides, all the doses of up to 10% Artemia salina did not produce undesirable side effects on the ocular surface. Therefore, these eye drops are presented as a possible new treatment for dry eye due to their secretagogue properties and ocular surface regeneration.

Effect of nutritional supplement based on melatonin on the intraocular pressure in normotensive subjects.

PURPOSE: To evaluate the effect of a new nutritional supplement based on melatonin on the intraocular pressure (IOP) in normotensive subjects. PATIENTS AND METHODS: A short-term prospective study was designed. Sixty-seven normotensive subjects were recruited. Patients were divided into two groups. The daily group (DG) (n = 18) was instructed to take the supplement between 22:00 and 23:00 (before sleeping) for 3 consecutive days. IOP was measured from 10.00 to 11.00 am the day before treatment and during the 3 days of experiment. The acute group (AG) (n = 49) was instructed to take the supplement after the second measure (11.00) of the second day. IOP was measured 1 h and just before the intake of the supplement and 1 and 2 h after. All measurements in this group were taken 1 day before without any supplement (control) and the day of experiment. RESULTS: The DG group showed a significant decrease in IOP after supplement intake in all days of experiment, from 14.9 ± 3.4 mm Hg to 13.8 ± 2.9 mm Hg after 3 days of experiment (p value < 0.001). For AG, IOP did not change during the control day; however, a reduction of 1 mm Hg was found 2 and 3 h after supplement intake, from 15.7 ± 2.5 mm Hg to 14.7 ± 2.5 mm Hg and 15.1 ± 2.7 mm Hg, respectively, being statistically significant (p value < 0.001). CONCLUSION: The supplement based on melatonin was able to reduce the IOP in normotensive subjects after 2 h of intake. Moreover, the daily intake showed a reduction in IOP during the 3 days of experiment.

Evaluation of tear meniscus by optical coherence tomography after different sodium hyaluronate eyedrops instillation.

PURPOSE: To evaluate changes in tear meniscus dynamics using optical coherence tomography (OCT) after the instillation of different concentrations of sodium hyaluronate (SH) ophthalmic solutions. METHODS: An experimental, double-masked, randomized study was performed. Twenty-three healthy subjects (16 women and seven men; mean age 23.57 ± 2.56 years) participated in this study. About 35 µl of 0.1%, 0.2%, 0.3% SH ophthalmic solutions and saline solution was instilled in a randomly assigned eye. Tear meniscus measurements (height, depth and turbidity) were taken with OCT at 30 seconds and 1, 3, 5, 10 and 20 min after instillation. Subsequently, the Schirmer test and tear break-up time (TBUT) were evaluated. RESULTS: Tear meniscus depth and tear meniscus height showed a significant increase with all solutions compared to basal values: up to 3 min for 0.1% SH, up to 5 min for 0.2% and up to 10 min for 0.3% SH ophthalmic solution. Tear meniscus turbidity was also increased at 30 seconds for 0.1%, 0.2% and 0.3% SH artificial tears (p < 0.05). This increase remained significant for up to 1 min for 0.2% and 0.3% SH solutions (p < 0.05). After 5 min of saline and 0.1% SH instillation, the turbidity was lower than basal values (p < 0.05). There was a significant increase in the TBUT for all solutions after instillation (p < 0.05). No differences between the Schirmer pre- and postinstillation were found (p > 0.05). Finally, the comfort was significantly improved for all ophthalmic solutions (p < 0.05). CONCLUSION: Sodium hyaluronate (SH) ophthalmic solutions increase residence time in healthy subjects and are positively correlated with its concentration and therefore the viscosity.

Therapeutic inhibitors for the treatment of dry eye syndrome.

INTRODUCTION: Dry eye disease (DED), defined as a multifactorial disease of tears and ocular surface, results in symptoms of discomfort, ocular irritation, visual disturbance and tear film instability. This syndrome is accompanied of ocular surface inflammation and it is produced by a deficient activity of the lacrimal functional unit. In addition, it is associated with systemic autoimmune diseases such as Sjögren´s Syndrome, rheumatoid arthritis, systemic lupus erythematosus and some drug administration. The treatment of dry eye disease is based on the typical signs and symptoms of dry eye, which are associated with hyperosmolarity, ocular surface inflammation, discomfort, visual disturbance, and tear film instability. Areas covered: This review is focused on synthetic drugs currently used in clinical practice, from phase III development onwards to treat the ocular surface signs and symptoms of dry eye disease. Expert opinion: The multifactorial disease and the lack of correlation between signs and symptoms imply that not all the pharmacological approaches will be successful for dry eye. The correct design of the clinical trials, with appropriate endpoints, and the type of dry eye under study are complicated but mandatory. The anti-inflammatory and secretagogues drugs are both the main compounds to currently treat the dry eye disease.

Post-lens tear turbidity and visual quality after scleral lens wear.

BACKGROUND: The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. METHODS: Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. RESULTS: A significant increase of turbidity was found in all groups assessed (p < 0.05). The number of particles per square millimetre was eight times higher after scleral lens wear than at the beginning of wearing the lens for all groups. VA decreases in all groups after scleral lens wear (p < 0.001). All patients showed a statistical diminishing of contrast sensitivity after scleral lens wear (p < 0.05). A significant correlation was found for both turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p < 0.05). CONCLUSION: The VA decrease during the scleral lens wearing, filled with preserved saline solution, was due to the increasing post-lens tear layer turbidity.