Effect of Instillation of Eyedrops for Dry Eye on Optical Quality

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.

Influence of perfluorohexyloctane (Evotears®) on higher order aberrations

PURPOSE

To prospectively assess the effect of regular application of perfluorohexyloctane (F6H8; Evotears®) on the tear film lipid layer, higher order aberrations (HOA) and the repeatability of measurements in healthy eyes.

METHODS

This prospective clinical study included 104 eyes treated with F6H8 four times daily for four weeks (group A) and 101 eyes that served as controls (group B). Measurements were performed with the WASCA aberrometer (Carl Zeiss Meditec GmbH, Jena, Germany). Main outcome measurement in addition to subjective refraction were the root mean square values of HOA measured before and after the intervention.

RESULTS

Regular use of F6H8 over a period of four weeks significantly increases HOA in healthy eyes (p < 0.05). In addition, the repeatability of measurement increases after the application of F6H8.

CONCLUSION

F6H8 may be a suitable treatment option to improve the accuracy of refractive assessment, although it increases HOA. Further studies are needed to confirm the effect on HOA and the repeatability of measurement.

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.

In Vitro and In-Eye Comparison of Commercial Pilocarpine Ophthalmic Solution and an Optimized, Reformulated Pilocarpine for Presbyopia Treatment

INTRODUCTION

Pilocarpine hydrochloride (pilo) ophthalmic solution has traditionally been used for the treatment of glaucoma, with opportunities to improve the tolerability profile experienced by patients. Pilocarpine hydrochloride ophthalmic solution 1.25% (Vuity™, Allergan, an AbbVie company) was approved in late 2021 for the treatment of adults with presbyopia. This publication describes the properties of the optimized, proprietary vehicle of this new ophthalmic solution developed with the aim of improving tolerability upon instillation.

METHODS

An in vitro method determined the time required for the pH of pilo 1.25% in the proprietary vehicle (Optimized Formulation) and a commercially available 1% pilo ophthalmic solution (Generic Formulation) to equilibrate with the pH of simulated tear fluid (STF). In a pilot study, five of the six screened participants received one drop of the Optimized Formulation in one eye and Generic Formulation in the other. Ocular discomfort and vision blur were evaluated for each eye just prior to and at multiple times after drop instillation using visual analog scales (VAS), and adverse events were assessed.

RESULTS

The in vitro method showed that the Optimized Formulation achieved faster pH equilibration than the Generic Formulation. The pilot study revealed that the Optimized Formulation demonstrated less ocular discomfort, vision blur, and adverse events compared to the Generic.

CONCLUSION

The in vitro and pilot study of the Optimized Formulation indicated that it rapidly equilibrates to the physiologic pH of the tear film, providing greater comfort and tolerability while also minimizing vision blur. Overall, the proprietary vehicle is expected to improve comfort, result in less vision blur, and provide a well-tolerated alternative method to deliver pilo for the treatment of presbyopia when compared to what is commercially available.

Effect of artificial tears on dynamic optical quality in patients with dry eye disease

BACKGROUND

In clinical practice, fluctuating vision or decreased quality of vision is a common complaint in DED patients. Our study was designed to investigate the change in dynamic optical quality in dry eye patients after the use of artificial tears.

METHODS

Fifty-nine patients with dry eye disease (DED) and 31 control subjects were included in this prospective case-control study. There was no significant difference in age and sex between these two groups (P = 0.342, P = 0.847, respectively). Clinical evaluation of the ocular surface included Ocular Surface Disease Index (OSDI), tear film break-up time (TBUT), lipid layer thickness (LLT), and Schirmer I test. DED patients were divided into two groups, mild (31 patients) and severe (28 patients). The optical quality of the tear film was measured with the Optical Quality Analysis System (OQAS) using the mean objective scatter index (mean OSI), standard deviation of objective scatter index (SD-OSI) and modulation transfer function cut-off (MTF cut-off). After baseline examinations, one drop of artificial tears (ATs, carboxymethylcellulose ophthalmic solution, 0.5%) was instilled in both eyes, and optical quality parameters were measured again at 5 and 30 min following application of ATs.

RESULTS

At baseline, the mean OSI was higher in the DED group (0.95 ± 0.54) than in controls (0.54 ± 0.23, P < 0.001). The SD-OSI was also significantly increased in DED patients (0.44 ± 0.71) compared to control subjects (0.12 ± 0.06, P = 0.003). Five minutes after AT instillation, mean OSI and SD-OSI decreased significantly in severe DED patients (P = 0.044; P = 0.018), remained unchanged in mild DED patients, and increased in the control group (P = 0.019; P < 0.001). Thirty minutes after AT instillation, no significant difference in optical quality parameters was observed among the three groups.

CONCLUSION

The effect of ATs on optical quality in patients with DED may differ according to the severity of the disease. Measurement of optical quality might be a promising tool to evaluate the effects of various ATs and possibly individualize treatment in DED patients.

Long-Term Outcome of Corneal and Anterior Chamber Angle Parameters after Combined Laser Iridotomy and Iridoplasty Using Dual Scheimpflug Analyzer: 1 Year Results

Background: To investigate the outcomes of corneal and anterior chamber angle (ACA) parameters after laser iridotomy (LI) combined with peripheral iridoplasty (PI) using dual Scheimpflug analyzer in the long term. Methods: Fifty-eight eyes (58 subjects) with shallow AC were included in this prospective cohort study. Images of the Dual Scheimpflug analyzer were obtained before, 1 week, and 1 year after LI and PI. Pachymetry from three zones (central, middle, and peripheral), corneal aberration, and spherical equivalent (SE) were acquired. AC depth (ACD), AC volume (ACV), ACA from four quadrants, and intraocular pressure (IOP) were also obtained. For comparison of the results, the linear mixed-effects model was employed. Results: ACD significantly increased from 2.09 ± 0.25 mm to 2.10 ± 0.23 mm at 1 year after laser (all p < 0.05). ACV and ACA increased significantly after laser at 1 year (all p < 0.05). IOP significantly decreased from 15.97 ± 4.20 mmHg to 13.73 ± 2.63 mmHg at 1 year (all p < 0.0001). No significant changes were found in the coma, trefoil, total corneal aberration, pachymetry from three zones, corneal volume, central corneal thickness, and SE after LI and PI until 1 year (all p > 0.05). Conclusions: LI plus PI ameliorated parameters of ACA efficiently and significantly reduced IOP in eyes with shallow AC until 1 year of long-term follow-up. However, parameters of the cornea and SE were not influenced by LI with PI until after 1 year.

Efficacy of Topical Hydrocortisone in Combination with Topical Ciclosporin A for the Treatment of Dry Eye Disease in Patients with Sjögren Syndrome

Introduction

The aim of this randomized, observer-masked, parallel group study was to evaluate the short-term and long-term effects of topical hydrocortisone administered in addition to topical ciclosporin A for the first 2 weeks of the treatment in patients with dry eye disease associated with Sjögren syndrome.

Materials and Methods

24 eyes of 12 patients with severe dry eye disease associated with Sjögren syndrome were included in this study. Both eyes of all patients were treated with preservative-free Ciclosporin A eye drops once daily for 6 months. Additionally, one eye of each patient received hydrocortisone eye drops three times daily for the first two weeks of treatment. The study parameters were assessed before treatment, after 2 weeks, and after 6 months of treatment.

Results

Tear BUT and corneal fluorescein Oxford staining grade showed significant differences with respect to the baseline when treated with ciclosporin A and hydrocortisone (CsA + Hc) and a nonsignificant increase when treated with ciclosporin A (CsA) alone. After 6 months of treatment, significant increases of tear BUT and corneal Fluorescein Oxford staining grade compared to baseline could be observed in both treatment groups. Aberrometry measurements showed significantly increased optical image quality after 6 months in the CsA + Hc group, while no significant changes could be detected in the eyes treated with CsA alone. However, no significant differences between the two treatment groups could be detected. Discussion. This study indicates that hydrocortisone combined with ciclosporin A therapy may provide fast improvement of clinical symptoms and could have long-term positive effects on the optical image quality in severe DED patients with Sjögren syndrome.

A Systematic Review on the Association Between Tear Film Metrics and Higher Order Aberrations in Dry Eye Disease and Treatment

We systematically reviewed published research on dry eye disease and its association with higher order aberrations (HOAs). The purpose of this review was to first determine if an association between tear film metrics and HOAs exists and second to determine if the treatment of dry eyes can improve tear film metrics and HOAs together. A search was conducted in Entrez PubMed on 25 April 2021 using the keywords “higher order aberrations” and “dry eye”. The initial search yielded 61 articles. After publications were restricted to only original articles measuring HOA outcomes in patients with dry eye, the final yield was 27 relevant articles. Of these 27 papers, 12 directly looked at associations and correlations between dry eyes and HOA parameters. The remaining 15 studies looked at dry eye interventions and HOA outcomes and parameters. There is clear evidence demonstrating that dry eyes and HOAs have an association, and that the tear film is one of the most important factors in this relationship. There is also a direct correlation between tear film metrics and HOAs. Improvements in HOAs with dry eye interventions provide further evidence to support the intricate relationship between the two. Despite the clear association between HOAs and dry eye disease, further research is still required in the realm of clinical application as dry eye interventions vary depending on many factors, including patient severity and eye drop viscosity.

Intraocular Scattering, Blinking Rate, and Tear Film Osmolarity After Exposure to Environmental Stress

Purpose

Dry environments, such as those in offices or aircraft cabins, can potentially generate ocular discomfort and alter the tear film. We compare light scatter, blinking rate, and tear osmolarity in young and older subjects after exposure to low humidity using a controlled environmental chamber.

Methods

Two groups of healthy subjects were recruited; younger (N = 13, 27 ± 6 years) and older (N = 23, 71 ± 7 years). Measurements were carried out before and after 90-minute exposure to low relative humidity (5%) and constant temperature (23 degrees). Ocular light scatter was measured using a double-pass instrument (OQAS, Visiometrics, Spain). Blinking rate was monitored using an infrared video camera. Tear osmolarity was measured using the TearLab system (Escondido, CA, USA).

Results

Ocular light scatter increased by a factor of 10% after exposure to low humidity in the older group (P = 0.03) but did not change significantly in the younger group. Blinking rate increased significantly (40% more blinks) in both groups but there was no difference between the groups. No significant differences in osmolarity were shown between two age groups or as result of environmental stress.

Conclusions

Exposure to dry environment increased light scatter in older subjects. Although more blinks were triggered in both younger and older groups to prevent corneal dehydration, there was no difference between the groups. Blink rate and osmolarity are not associated with the difference in light scatter.

Translational Relevance

Our work approaches a clinical care problem using basic research methods (measuring ocular scatter and blink ratio).

Funktionelle Sehschärfe beim Trockenen Auge

Das Trockene Auge führt häufig zu Sehstörungen trotz guter Sehleistung in der Standardvisusprüfung. Die Beschwerden treten meist beim Lesen, Arbeiten am Computer und/oder beim Autofahren auf. Grund ist die schlechte optische Qualität der Augenoberfläche beim Trockenen Auge mit Zunahme von topometrischer Irregularität und Asymmetrie, Anstieg des irregulären Astigmatismus, Zunahme der kornealen und okulären Aberrationen höherer Ordnung, Abnahme der Kontrastsensitivität und Zunahme der Lichtstreuung. Die funktionelle Sehschärfe repräsentiert die Visusfunktion im Zeitverlauf und reflektiert die Visusleistung eines Individuums bei täglichen Aktivitäten. Sie ist beim Trockenen Auge signifikant reduziert im Vergleich zu Normalprobanden. Eine Vielzahl von Testmethoden zur Evaluierung der funktionellen Sehschärfe wurde beschrieben. Kein Verfahren hat sich bisher in der täglichen Praxis durchgesetzt.

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.

Influence of Artificial Tears on Keratometric Measurements in Cataract Patients

PURPOSE

To assess the influence of artificial tears of different viscosity on K-readings prior to cataract surgery.

DESIGN

Prospective randomized crossover, before-and-after clinical study.

METHODS

Setting: Department of Ophthalmology, Medical University of Vienna.

PATIENT POPULATION

A total of 123 eyes of 80 patients prior to cataract surgery were assigned to 2 groups based on normal and dry eyes.

INTERVENTION

Two native baseline keratometries were followed by instillation of either high- or low-viscosity eye drops. Keratometry was repeated 30 seconds, 2 minutes, and 5 minutes after instillation.

MAIN OUTCOME MEASURES

Influence of eye drops of different viscosity in normal and dry eyes on short time K-readings.

RESULTS

Repeatability between native baseline measurements was high (standard deviation = 0.02 mm in normal and in dry eyes). In normal and dry eyes, a statistically significant increase in measurement variability after instillation of both low-viscosity and high-viscosity eye drops was observed (P < .01). Measurement variability was most pronounced between baseline measurement and 30 seconds and diminished over time. Variability of K-readings appeared higher in dry eyes compared with normal eyes. Astigmatism changed more than 0.5 diopters in 13.2% of normal eyes and 34.4% in dry eyes using eye drops of high viscosity.

CONCLUSION

Tear film-stabilizing eye drops prior to keratometry measurements influenced K-readings significantly, especially in dry eyes. A time period of more than 5 minutes should be allowed to pass after instillation of eye drops. The higher the viscosity of the eye drops, the stronger the influence and the longer its persistence.

The short term effect of trehalose and different doses of sodium hyaluronate on anterior corneal aberrations in dry eye patients

AIM

To evaluate the short-term effect of 0.15% sodium hyaluronate (SH), 0.20% SH, and Trehalose + 0.15% SH on anterior corneal aberrations in dry eye patients.

METHODS

76 eyes of 76 dry eye patients were divided into three groups. Non-preserved 1.5 mg/mL SH was administered in group 1, non-preserved 2.0 mg/mL SH was administered in group 2, and non-preserved trehalose 30 mg/mL and 1.5 mg/mL SH was administered in group 3. Aberrometry measurements were performed before and 10 min after application of the artificial tear drop. Using the Pentacam Scheimpflug imaging system, total root mean square (RMS), lower-order aberration (LOA), higher-order aberrations (HOAs), spherical aberration (SA), trefoil, and coma aberrations were investigated.

RESULTS

In each group; the RMS of total, LOA, HOAs, and spherical aberration were significantly decreased after the artificial drop instillation, compared with those of them at baseline; and in groups 1 and 2, vertical trefoil term was also significantly increased, compared with those of them at baseline. According to intergroup analyzes, there was no significant outcome.

CONCLUSIONS

It was observed that three artificial tears reduced the anterior corneal aberrations, in a 10-min period. The short-term effect of three artificial tears on the anterior corneal aberration was similar.

Objective Imaging Diagnostics for Dry Eye Disease

Traditional diagnostic tests for dry eye disease (DED), such as fluorescein tear film break-up time and the Schirmer test, are often associated with poor reproducibility and reliability, which make the diagnosis, follow-up, and management of the disease challenging. Advances in ocular imaging technology enables objective and reproducible measurement of changes in the ocular surface, tear film, and optical quality associated with DED. In this review, the authors will discuss the application of various imaging techniques, such as, noninvasive tear break-up time, anterior segment optical coherence tomography, in vivo confocal microscopy, meibography, interferometry, aberrometry, thermometry, and tear film imager in DED. Many studies have shown these devices to correlate with clinical symptoms and signs of DED, suggesting the potential of these imaging modalities as alternative tests for diagnosis and monitoring of the condition.

Corneal topography and angle parameters after laser iridotomy combined with iridoplasty assessed by dual Scheimpflug analyzer

PURPOSE

To investigate the changes in corneal topography including parameters such as corneal curvature and corneal aberrations, along with anterior chamber angle (ACA) after laser iridotomy (LI) combined with peripheral iridoplasty (PI) using dual Scheimpflug analyzer.

METHODS

In this prospective observational study, dual Scheimpflug analyzer images were acquired before and 1 week after LI plus PI. Corneal curvature of both axial and instantaneous maps from anterior and posterior surface, respectively, and total corneal power (TCP) were acquired. These corneal parameters from three zones (central, middle, and peripheral) and total corneal wavefront aberration, trefoil, and coma were obtained. The ACA from four quadrants, anterior chamber depth (ACD), anterior chamber volume (ACV), and intraocular pressure (IOP) were also inspected.

RESULTS

ACD increased significantly from 2.15 ± 0.25 to 2.18 ± 0.24 mm (P = 0.002). ACV and ACA from all four quadrants increased significantly after the laser treatment (all P < 0.05). IOP decreased significantly from 16.9 ± 3.1 to 14.7 ± 2.9 mmHg following LI plus PI (P = 0.000). No significant changes were detected in corneal axial and instantaneous curvature from three zones on the anterior and posterior corneal surface after LI plus PI (all P > 0.05). The TCP, total corneal wavefront aberration, trefoil, and coma also revealed no significant changes after the laser procedure (all P > 0.05).

CONCLUSIONS

Treatment with LI combined with PI did not affect the corneal topographic parameters from both anterior and posterior surfaces. However, LI plus PI improved ACA parameters significantly and effectively.

Medical Treatment for Dry Eye in Japan

The etiology of dry eye has not been clarified. In the United States, the inflammation theory is supported as the main cause of dry eye, whereas the Asia Dry Eye Society has identified tear instability as the main cause. Based on this tear instability concept, the P2Y2 antagonist Diquas and the mucin secretagogue Mucosta were developed and launched in Japan over the last 5 years, and they have been widely prescribed to patients with dry eye. Moreover, Diquas has also been launched in other Asian countries, such as Korea, Thailand, and Vietnam. This report summarizes the efficacy and characteristics of these two eye drops to improve our understanding of dry eye.

The Effect of Corneal Higher Order Aberrations on Postoperative Residual Astigmatism after Toric IOL Implantation

Background: To demonstrate the effect of preoperative higher order aberrations (HOAs) on postoperative residual astigmatism in toric intraocular lens (IOL) implantation. Methods: A retrospective, controlled, comparative study that involved patients who underwent toric IOL implantation. Patients were divided into two groups according to the difference between the estimated residual astigmatism and actual postoperative astigmatism [difference ≤0.5 diopters (D), Group A; difference >0.5 D, Group B]. Corneal astigmatisms with axis, and various aberration values were compared between the two groups. Results: Total RMS and HOA RMS values in Group B were significantly higher than those in Group A (p < .001, = 0.003). The vertical coma value, and its absolute value, in Group B were significantly higher than those in Group A (p < .001, = 0.002). The total RMS and absolute value of the vertical coma showed a positive linear correlation with the degree of residual postoperative astigmatism (R-square = 0.139, 0.131; p = .027, 0.036). Conclusions: If the residual astigmatism after insertion of the toric IOL was greater than expected, corneal aberrations, shown by total RMS and HOA RMS values before surgery, especially of the vertical coma, tended to be high.

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.

Immediate effect of a tear enhancer and meibomian gland expression on the corneal surface and whole eye higher order aberrations

PURPOSE

To investigate changes in higher order ocular aberrations (HOA) induced by the administration of 0.15% sodium hyaluronate tear enhancer (TE) and meibomian gland expression (ME) on the tear film of normal subjects.

METHODS

HOA values were obtained from the corneal surface (CS) and whole eye (WE), using a corneal topographer and Shack-Hartmann aberrometer, from both eyes of 50 subjects (25 females, mean age±sd 32.5±11.0 years, and 25 males, 33.88±11.2 years) for two pupil sizes (3 and 6mm) in a dark environment. One drop of Blink Contacts™ (Abbott Medical Optics) was instilled into the right eye and HOA measurements repeated after 30s. After 1h, the meibomian glands of the left lower eyelid were gently squeezed and HOA measurements repeated after 30s.

RESULTS

There was no significant difference for CS and WE root mean square (RMS) HOAs between right and left eyes before (both pupil sizes) and after TE use or ME (3mm pupil). For 6mm pupil, TE use significantly reduced the WE RMS HOA (p<0.05, mean±sd) for Z40 (0.297±0.136 to 0.053±0.069), and Z55 (0.221±0.372 to 0.098±0.121) while ME significantly increased CS RMS HOA (p<0.05, mean±sd) for Z3-3 (0.799±1.178 to 1.302±1.991) and Z44 (0.594±1.184 to 0.988±1.463). In general, the change in HOA was significantly correlated with the initial value before TE use or ME (p<0.05).

CONCLUSION

There were no detectable differences between right and left eyes. For the 6mm pupil, the tear enhancer tended to improve optical performance of the WE and meibomian gland expression tended to reduce the optical performance at the CS.

Effects of Lipid- Versus Sodium Hyaluronate-Containing Eye Drops on Optical Quality and Ocular Surface Parameters as a Function of the Meibomian Gland Dropout Rate

PURPOSE

To evaluate the effect of lipid- versus sodium hyaluronate-based eye drops on optical quality and ocular surface parameters.

METHODS

Sixty eyes of 30 patients with mild-to-moderate dry eye disease were included in a prospective randomized study. Each patient received either lipid- or sodium hyaluronate-based eye drops. Ocular symptom scores, breakup time, Schirmer test, fluorescein staining, noncontact meibography, and aberrometry were evaluated before and after 3 months of therapy.

RESULTS

At the 3-month visit, a statistically significant improvement (P ≤ 0.05) was noted in both groups on the Schirmer test, breakup time, ocular surface staining, and symptom score. In the lipid group, patients with progressive meibomian gland (MG) loss (>50%) showed a significantly greater increase in their corneal higher-order (HO) Strehl ratio (0.25 ± 0.26 vs. -0.01 ± 0.25, P = 0.02) and modulation transfer function (MTF) (0.12 ± 0.17 vs. -0.02 ± 0.06, P = 0.03) than patients with less advanced MG disease. In the lipid group, a significant positive correlation was noted between the MG dropout rate and improvement in Schirmer values [Spearman correlation coefficient (CC): 0.79], corneal HO Strehl (CC: 0.75), and HO modulation transfer function (CC: 0.6), but a significant negative correlation was noted between the MG dropout rate and the HO root mean square (CC: -0.73).

CONCLUSIONS

Lipid-containing artificial tears seem to be superior to sodium hyaluronate-containing drops in terms of improving HO aberrations and optical quality in patients with significant MG dysfunction.

Effects of tear film dynamics on quality of vision

The precorneal tear film is maintained by blinking and exhibits different phases in the tear cycle. The tear film serves as the most anterior surface of the eye and plays an important role as a first refractive component of the eye. Alterations in tear film dynamics may cause both vision-related and ocular surface-related symptoms. Although the optical quality associated with the tear film dynamics previously received little attention, objective measurements of optical quality using wavefront sensors have enabled us to quantify optical aberrations induced by the tear film. This has provided an objective method for assessing reduced optical quality in dry eye; thus, visual disturbances were included in the definition of dry eye disease in the 2007 Dry Eye Workshop report. In addition, sequential measurements of wavefront aberrations have provided us with valuable insights into the dynamic optical changes associated with tear film dynamics. This review will focus on the current knowledge of the mechanisms of wavefront variations that are caused by different aspects of tear film dynamics: specifically, quality, quantity and properties of the tear film, demonstrating the respective effects of dry eye, epiphora and instillation of eye drops on the quality of vision.

Influence of Sodium Hyaluronate Concentration on Corneal Aberrations in Soft Contact Lens Wearers

Purpose

This study aimed to evaluate the influence of varying concentrations of sodium hyaluronate (SH) eye drops on corneal aberrations in normal individuals wearing silicone hydrogel contact lenses.

Methods

Normal individuals wearing silicone hydrogel contact lenses were enrolled in this study. Subjects were classified into two groups depending on the concentration of the preservative-free SH used (group 1, 0.1% SH; group 2, 0.3% SH). All subjects were asked to blink five times after instillation of the SH eye drop and before the Galilei measurements. Corneal aberrations were measured over the contact lenses before and after SH eye drop instillation. Visual acuity (VA) over the contact lenses was also measured both before instillation of the SH eye drop and after the subjects completed the five blinks.

Results

There was no change in VA after SH instillation in group 1; however, group 2's VA significantly deteriorated after SH instillation. Changes in VA after SH instillation compared to baseline were significantly higher in group 2 than in group 1. Similarly, the increase in corneal aberrations after SH instillation was significant in group 2 but not significant in group 1. Among the significantly increased corneal aberration parameters, defocus was the main type in group 2. Changes in corneal aberrations after SH instillation compared to baseline were significantly higher in group 2 than in group 1.

Conclusions

A 0.3%-concentration of SH increases corneal aberration and decreases VA in soft contact lens wearers. Defocus is the main type of aberration that increased in the 0.3% SH instillation group.

Comparison of objective optical quality measured by double-pass aberrometry in patients with moderate dry eye: Normal saline vs. artificial tears: A pilot study

Dry eye is defined by a tear film instability resulting in variable but systematic fluctuations in quality of vision. Variability in optical quality can be demonstrated using a double pass aberrometer such as the Optical Quality Analyzing System, Visiometrics (OQAS). The goal of this work is to compare fluctuations in objective quality of vision measured by OQAS between treatment with normal saline eye drops and treatment with carmellose 0.5% and hyaluronic acid 0.1% (Optive Fusion [OF], Allergan) in patients with moderate dry eye syndrome. Optical quality was measured by evaluating the variations in the Optical Scattering Index (OSI) over 20seconds using the OQAS. Inclusion criteria were dry eye syndrome with an ocular surface disease index (OSDI) score >23 treated only with artificial tears. The patients were their own controls: OF in one eye and normal saline in the fellow eye. The choice of the subject eye and control eye was determined in a randomized fashion. OSI variations were measured in each eye before instillation, 5minutes and 2hours after instillation. The primary endpoint was OSI fluctuation over 20seconds of measurement. Secondary endpoints were the number of blinks and patient preference (preferred eye). Preliminary results were obtained on 19 patients. Average OSDI score was 36.8. Visual acuity was 10/10 with no significant difference between the two eyes. Prior to instillation, there was no significant difference between "normal saline" and "OF" eyes in terms of OSI, OSI variability or number of blinks. In the normal saline eye, there were no significant variations in mean OSI, OSI variability, OSI slope, or number of blinks. However, in the "OF" eye, there was a significant variation between initial and 2-hour OSI variability (0.363 versus 0.204, P<0.05), the average slope of OSI (0.04 versus 0.01, P<0.05) and the number of blinks (4.2 versus 2.8, P<0.05). Among the patients, 65% preferred the OF eye, 24% did not have a preference, and 11% preferred the normal saline eye. Objective quality of vision measured by OQAS is an interesting parameter for evaluating the effectiveness of a lacrimal substitute. The purpose of artificial tears is, among other things, to provide comfort and a reduction of dry eye symptoms such as poor quality of vision. This study demonstrates that 0.5% carmellose and 0.1% hyaluronic acid allowed better stabilization of the tear film and thus a significant improvement in the quality of vision compared to normal saline.

Advances in dry eye imaging: the present and beyond

New advances in imaging allow objective measurements for dry eye as well as define new parameters that cannot be measured by clinical assessment alone. A combination of these modalities provides unprecedented information on the static and dynamic properties of the structural and functional parameters in this multifactorial disease. A literature search was conducted to include studies investigating the use of imaging techniques in dry eye disease. This review describes the application of non-invasive tear breakup time, optical coherence tomography, meibomian gland imaging, interferometry, in vivo confocal microscopy, thermography and optical quality assessment for this condition.

Effect of different lubricant eye gels on tear film thickness as measured with ultrahigh-resolution optical coherence tomography

PURPOSE

To compare the effect of a single drop of different lubricant eye gels on tear film thickness (TFT) as measured with ultrahigh-resolution optical coherence tomography (UHR-OCT) in patients with mild-to-moderate dry eye disease (DED).

METHODS

The study followed a randomized, single-masked, observer-blinded parallel group design. Patients received a single dose of either unpreserved trehalose 3% + hyaluronic acid 0.15% (TH), hyaluronic acid 0.2% (HA) or polyethylene glycol 0.4% + propylene glycol 0.3% (PP) eye drops. In total, 60 patients were included and TFT was measured using a custom-built UHR-OCT system.

RESULTS

The mean TFT at baseline was 3.5 ± 0.7 μm. There was a significant difference in the time-course of TFT between the three groups (p = 0.001 between groups). Ten minutes after instillation, TFT increased by 155.8 ± 86.6%, 65.7 ± 71.5% and 33.4 ± 19.6% in the PP, TH and HA group, respectively (p < 0.001 between groups). Thirty minutes after instillation, the effect of all three different agents on TFT was comparable. Sixty and 120 min after administration, a significant increase in TFT was only seen for the TH group, but not for the other products (60 min: p < 0.021 between groups; 120 min: p < 0.037 between groups).

CONCLUSION

In conclusion, we observed differences in TFT after administration of the lubricant gels. Ten minutes after instillation, a pronounced increase in TFT was observed in all groups. As compared to the other products, the combination of trehalose 3% + hyaluronic acid 0.15% offers a significantly longer increase in TFT indicating for a longer residence time.

Evaluation of Tear Meniscus Dynamics Using Anterior Segment Swept-Source Optical Coherence Tomography After Topical Solution Instillation for Dry Eye

PURPOSE

To investigate tear meniscus dynamics using anterior segment swept-source optical coherence tomography (SS-OCT) after the instillation of topical solutions for dry eye.

DESIGN

Prospective, observational, cross-sectional study.

METHODS

Thirty-six healthy subjects (28 men and 8 women; mean age, 34.4 ± 6.7 years) were enrolled in this study. The lower tear meniscus height, tear meniscus area, and tear meniscus volume were assessed using anterior SS-OCT. After baseline measurements, 40 μL of 0.1% sodium hyaluronate, 0.3% sodium hyaluronate, 3% diquafosol ophthalmic solution, or 2% rebamipide ophthalmic solution was instilled in one eye of 10 subjects each, whereas 40 μL saline was instilled in the other eye. Tear meniscus measurements were obtained using SS-OCT at 30 seconds and 1, 3, 5, 10, 15, 20, and 30 minutes after instillation.

RESULTS

The tear meniscus measurements showed a significant increase until 1, 3, 10, 10, and 3 minutes after the instillation of saline, 0.1% sodium hyaluronate, 0.3% sodium hyaluronate, 3% diquafosol, and 2% rebamipide, respectively, compared with the baseline levels (P < 0.05). Compared with those after saline instillation, the tear meniscus measurements were significantly higher until 30 seconds and 3, 30, and 15 minutes after the instillation of 0.1% sodium hyaluronate, 0.3% sodium hyaluronate, 3% diquafosol, and 2% rebamipide, respectively (P < 0.05).

CONCLUSIONS

The instillation of ophthalmic solutions for the treatment of dry eye greatly increased tear meniscus measurements in healthy subjects. Thus, SS-OCT can be a practical tool for the quantitative evaluation of early-phase tear fluid dynamics.

The role of dinucleoside polyphosphates on the ocular surface and other eye structures

Dinucleoside polyphosphates comprises a group of dinucleotides formed by two nucleosides linked by a variable number of phosphates, abbreviated NpnN (where n represents the number of phosphates). These compounds are naturally occurring substances present in tears, aqueous humour and in the retina. As the consequence of their presence, these dinucleotides contribute to many ocular physiological processes. On the ocular surface, dinucleoside polyphosphates can stimulate tear secretion, mucin release from goblet cells and they help epithelial wound healing by accelerating cell migration rate. These dinucleotides can also stimulate the presence of proteins known to protect the ocular surface against microorganisms, such as lysozyme and lactoferrin. One of the latest discoveries is the ability of some dinucleotides to facilitate the paracellular way on the cornea, therefore allowing the delivery of compounds, such as antiglaucomatous ones, more easily within the eye. The compound Ap₄A has been described being abnormally elevated in patient's tears suffering of dry eye, Sjogren syndrome, congenital aniridia, or after refractive surgery, suggesting this molecule as biomarker for dry eye condition. At the intraocular level, some diadenosine polyphosphates are abnormally elevated in glaucoma patients, and this can be related to the stimulation of a P2Y₂ receptor that increases the chloride efflux and water movement in the ciliary epithelium. In the retina, the dinucleotide dCp₄U, has been proven to be useful to help in the recovery of retinal detachments. Altogether, dinucleoside polyphosphates are a group of compounds which present relevant physiological actions but which also can perform promising therapeutic benefits.

Changes of Corneal Wavefront Aberrations in Dry Eye Patients after Treatment with Artificial Lubricant Drops

Purpose. To evaluate the corneal aberration changes in dry eye patients after treatment with artificial eye drops. Methods. Thirty mild to moderate dry eye patients treated with artificial eye drops and twenty comparable dry eye patients were recruited as controls. Anterior corneal aberrations over 3 mm and 5 mm analytical zones including total, 3rd to 5th high order aberrations (HOAs), spherical aberration (SA), and vertical (V-coma) and horizontal coma (H-coma) obtained from corneal topography data at baseline and 2 weeks after treatment were evaluated. Results. For 3 mm zone, trefoils, V-coma, H-coma terms, and 3rd and 5th HOAs were significantly decreased (p < 0.05) in the treatment group. For 5 mm zone, instillation of eye drops reduced H-coma, SA terms, 3rd to 5th orders, and total HOAs all showed a significant decrease (p < 0.05). The root mean square analysis of the Zernike terms also showed similar statistical results. For control group, all individual terms and total HOAs did not have significant changes over 3 mm and 5 mm zones (p > 0.05). Conclusions. Treatment with artificial eye drops can effectively improve the corneal optical quality of dry eye patients by ameliorating the HOAs of anterior corneal surface.

Diquafosol ophthalmic solution 3 %: a review of its use in dry eye

Diquafosol ophthalmic solution 3 % (Diquas(®)) is a P2Y2 receptor agonist that promotes tear fluid and mucin secretion and is currently approved in Japan and South Korea for the treatment of dry eye. In randomized, double-blind, multicentre trials in patients with dry eye, significantly greater improvements in fluorescein and rose bengal staining scores were seen with diquafosol ophthalmic solution 3 % than with placebo, and diquafosol ophthalmic solution 3 % was noninferior to sodium hyaluronate ophthalmic solution 0.1 % in terms of the improvement in the fluorescein staining score and more effective than sodium hyaluronate ophthalmic solution 0.1 % in terms of the improvement in the rose bengal staining score. The efficacy of diquafosol ophthalmic solution 3 % in the treatment of dry eye was maintained in the longer term, with improvements also seen in subjective dry eye symptoms, and was also shown in a real-world setting. Diquafosol ophthalmic solution 3 % also demonstrated efficacy in various specific dry eye disorders, including aqueous-deficient dry eye, short tear film break-up time dry eye, obstructive meibomian gland dysfunction, dry eye following laser in situ keratomileusis surgery and dry eye following cataract surgery, as well as in contact lens wearers and visual display terminal users. Diquafosol ophthalmic solution 3 % was generally well tolerated in patients with dry eye, with eye irritation the most commonly reported adverse event. In conclusion, diquafosol ophthalmic solution 3 % is a useful option for the treatment of dry eye.

Clinical utility of 3% diquafosol ophthalmic solution in the treatment of dry eyes

Diquafosol is a drug used for dry eye treatment with a novel mechanism of action. It stimulates the secretion of tear fluid and mucin on the ocular surface, thus enabling us to selectively treat the tear film layer, playing an important role in the establishment of the concept of "Tear Film Oriented Therapy (TFOT)", an effective therapeutic approach to dry eye in Japan. The 3% diquafosol ophthalmic solution has been widely used for the treatment of dry eye in clinical practice, and it is currently available in Japan and South Korea. This review provides an overview of the clinical utility of 3% diquafosol ophthalmic solution, focusing on the results of clinical studies on various types of dry eye, including aqueous-deficient dry eye, short tear film breakup time-type dry eye, and post dry eye after laser in situ keratomileusis. It also introduces the additive effect of diquafosol on sodium hyaluronate monotherapy for dry eye, and the effect of 3% diquafosol ophthalmic solution for dry eye-related conditions. Additionally, it summarizes the ocular effects of diquafosol in healthy human eyes. Lastly, the importance of improving tear film stability in dry eye treatment, as well as general advances in dry eye treatments, are described.

Clinical applications of wavefront refraction

Purpose

To determine normative reference ranges for higher-order wavefront error (HO-WFE), compare these values with those in common ocular pathologies, and evaluate treatments.

Methods

A review of 17 major studies on HO-WFE was made, involving data for a total of 31,605 subjects. The upper limit of the 95% confidence interval (CI) for HO-WFE was calculated from the most comprehensive of these studies using normal healthy patients aged 20 to 80 years. There were no studies identified using the natural pupil size for subjects, and for this reason, the HO-WFE was tabulated for pupil diameters of 3 to 7 mm. Effects of keratoconus, pterygium, cataract, and dry eye on HO-WFE were reviewed and treatment efficacy was considered.

Results

The calculated upper limit of the 95% CI for HO-WFE in a healthy normal 35-year-old patient with a mesopic pupil diameter of 6 mm would be 0.471 μm (471 nm) root-mean-square or less. Although the normal HO-WFE increases with age for a given pupil size, it is not yet completely clear how the concurrent influence of age-related pupillary miosis affects these findings. Abnormal ocular conditions such as keratoconus can induce a large HO-WFE, often in excess of 3.0 μm, particularly attributed to coma. For pterygium or cortical cataract, a combination of coma and trefoil was more commonly induced. Nuclear cataract can induce a negative spherical HO-WFE, usually in excess of 1.0 μm.

Conclusions

The upper limit of the 95% CI for HO-WFE root-mean-square is about 0.5 μm with normal physiological pupil sizes. With ocular pathologies, HO-WFE can be in excess of 1.0 μm, although many devices and therapeutic and surgical treatments are reported to be highly effective at minimizing HO-WFE. More accurate normative reference ranges for HO-WFE will require future studies using the subjects’ natural pupil size.

Effect of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye

PURPOSE

To investigate the short- and long-term effects of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye.

METHODS

Sixteen eyes in 16 patients with mild or moderate aqueous-deficient dry eye were treated with 3% diquafosol ophthalmic solution. Ocular higher-order aberrations (HOAs) were measured with a wavefront sensor before and at 15 min after diquafosol instillation at the baseline visit and at 4 weeks after treatment initiation. Dry eye symptoms, tear break-up time (BUT), corneal/conjunctival fluorescein staining and Schirmer's test were also evaluated before and after treatment with diquafosol.

RESULTS

Treatment with diquafosol ophthalmic solution significantly improved dry eye symptoms, corneal staining and BUT. Compared with mean total HOAs at baseline (0.180 ± 0.06 μm), those at 4 weeks after treatment significantly decreased (0.148 ± 0.039 μm; p = 0.035), whereas those 15 min after diquafosol instillation at the baseline visit did not change significantly (0.170 ± 0.049 μm; p = 0.279).

CONCLUSIONS

Although no significant change in HOAs was observed as a short-term effect of a single-drop instillation of diquafosol, long-term use of diquafosol to treat aqueous-deficient dry eye reduced HOAs as well as improved corneal epithelial damage and tear film stability.

Rebamipide ophthalmic suspension for the treatment of dry eye syndrome: a critical appraisal

Rebamipide was initially developed and approved for use in treating gastric ulcers and lesions associated with gastritis. Discovery of its ability to increase gastric mucin led to investigations of its effect on ocular surface mucin and the subsequent development for use in dry eye patients. Investigations have confirmed that rebamipide increases corneal and conjunctival mucin-like substances along with improving corneal and conjunctival injury. Clinically, rebamipide ophthalmic suspensions can effectively treat tear deficiency and mucin-caused corneal epithelial damage, and can restore the microstructure responsible for tear stability. Topical rebamipide has also been shown to be effective in treating other ocular surface disorders such as lagophthalmos, lid wiper epitheliopathy, and persistent corneal erosion. Rebamipide's ability to modify epithelial cell function, improve tear stability, and suppress inflammation in the absence of any known major side effects suggest that it may be a beneficial first drug of choice for severe dry eye treatment and other ocular surface disorders. This review summarizes the history and development of this innovative dry eye treatment from its initial use as an effective stomach medication to its current use in the treatment of dry eye in Japan.