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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.

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.

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.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.In tear secretion, there was an increase of 43.88 ± 6.73% with 4% Artemia salina in comparison with its baseline measurement (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.

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.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 mmA 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).The VA decrease during the scleral lens wearing, filled with preserved saline solution, was due to the increasing post-lens tear layer turbidity.

To evaluate the effect of a new nutritional supplement based on melatonin on the intraocular pressure (IOP) in normotensive subjects. 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. 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

To evaluate changes in tear meniscus dynamics using optical coherence tomography (OCT) after the instillation of different concentrations of sodium hyaluronate (SH) ophthalmic solutions.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.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).Sodium hyaluronate (SH) ophthalmic solutions increase residence time in healthy subjects and are positively correlated with its concentration and therefore the viscosity.