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

Corneal layer thickness in keratoconus using optical coherence tomography

CLINICAL RELEVANCE

Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures.

BACKGROUND

To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT).

METHODS

This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs.

RESULTS

In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001)                                    .

CONCLUSION

CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN.

Bacterial contamination of multi-use tear drops, gels, and ointments

PURPOSE

This study aimed to investigate the bacterial contamination of multi-use tear drops, gels, and ointments that patients use at home.

METHOD

A total of 271 multi-use containers used by 168 patients were examined. Conjunctival culture samples were obtained from patients who used tear drops, gels, and ointments that were found to be contaminated.

RESULTS

Bacterial contamination was detected in 33 (12.2 %) out of the 271 containers. The contamination rate was 7.9 % in tear drops, 11.7 % in gels, and 32 % in ointments. A statistically significant difference was found between the drops, gels, and ointment groups (P = 0.04). Bacterial contamination was detected in 25 (18.9 %) out of 132 collapsible tubes and 8 (5.8 %) out of 139 plastic bottles (P = 0.01). Important bacteria, including Pseudomonas stutzeri, Pseudomonas aeruginosa, Bacillus licheniformis, Paenibacillus pabuli, Proteus mirabilis, Pantoea agglomerans, Morganella morganii, Serratia marcescens, and Serratia liquefaciens, were detected. Mucorales spp. fungus was seen in a gel. Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, and M. morganii were found in the conjunctival microbiota of three patients.

CONCLUSION

The overall contamination rate of ocular lubricants was low (12.2%); however, a significant difference was found between the drops, gels, and ointments. The contamination rate was higher in gels and ointments than that in drops. The contamination rate was found to be increased in the collapsible tube. The use of ocular lubricants is safe; however, patients must be cautious when using multi-use tear drops, gels, and ointments to avoid contamination. Whenever possible, bottles should be preferred instead of collapsible tubes.

High-Resolution Imaging of the Ocular Vasculature of Conjunctivitis in Mice Using Highly Bright Polymer Dots

Ocular diseases are mainly caused by vascular aberrations in the eye, and accurate imaging and analysis of the ocular vascular structure is crucial. In this study, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PFBT) polymer dots (Pdots), with the advantages of easy synthesis, high brightness, and low toxicity, are used as nanoprobes to perform high-resolution imaging of the vasculature of the eyeball and optic nerve. Moreover, rapid imaging of the choroidal microvessels is carried out by stereoscopic fluorescence microscopy with a resolution of up to 1.6 µm. The comprehensive 3D vascular information of retinal aorta and optic nerve microvessels is obtained by combining tissue clearing and multiphoton microscopy. In addition, the vascular density of Schlemm's canal and iris blood vessels is compared between the conjunctivitis mice and the normal mice. These results suggest that PFBT Pdots have great application potential in the fast and accurate imaging of ocular diseases.

Lipid, Aqueous and Mucin Tear Film Layer Stability and Permanence within 0.15% Liposome Crosslinked Hyaluronic Acid versus 0.15% Non-Crosslinked Hyaluronic Acid Measured with a Novel Non-Invasive Ocular Surface Analyzer

To evaluate the stability and permanence of the liquid film created after the instillation of 0.15% crosslinked hyaluronic acid with liposomes and crocin versus the effect of 0.15% standard hyaluronic acid, a prospective, longitudinal, single-blind, single-center study was conducted in symptomatic populations with a novel noninvasive ocular surface analyzer. Limbal and bulbar redness classification, lipid layer thickness, tear meniscus height, and first and mean noninvasive break-up time (FNIBUT and MNIBUT) were performed before and 30 and 45 min after liposome-crosslinked hyaluronic acid (LCHA) and standard hyaluronic acid (HA) eye drop instillations. LCHA had a higher lipid layer thickness than HA (grades 2.00 ± 0.83 and 1.17 ± 0.63 on the Guillon pattern, respectively). LCHA achieved a better tear meniscus height than HA (0.23 ± 0.02 and 0.21 ± 0.02 mm, respectively). LCHA improved FNIBUT and MNIBUT more than HA (for FNIBUT, 6.30 ± 0.94 and 4.77 ± 0.89 s, respectively. For MNIBUT, 17.23 ± 5.11 and 12.41 ± 4.18 s, respectively). Crosslinking hyaluronic acid with liposomes and crocin significantly increases the permanence and stability of the lipid, aqueous, and mucin tear film layers. In a short-term period, liposome and crosslinked hyaluronic acid achieved better first and mean noninvasive break-up times than standard hyaluronic acid.

Improving ocular surface comfort in contact lens wearers

PURPOSE

Contact lens discomfort (CLD) is a major concern that can lead to the decreased or abandoned use of contact lenses. Contact lens users with dry eye disease are more likely to present with CLD. This study was conducted to evaluate the efficacy of a bioprotective preservative free, hypotonic, 0.15% hyaluronic acid (HA)-3% Trehalose artificial tear in managing dry eye symptoms in contact lens wearers.

METHODS

A prospective, single-arm, observational pilot study to evaluate the effectiveness of treatment with HA-Trehalose artificial tears in contact lens wearers (N = 33) aged 18-45 years with symptoms of ocular discomfort. Participants used a preservative-free, hypotonic HA-Trehalose artificial tear (1 drop/4 times per day) for 84 days. Participants were assessed using Visual Analogue Scale (VAS) for dry eye symptoms (pain, photophobia, dry eye sensation, blurry vision, foreign body sensation, itching, tingling/burning, and sticky eye feeling), Ocular Surface Disease Index (OSDI), Contact Lens Dry Eye questionnaire (CLDEQ-8), Berkley Dry Eye Flow-Chart (DEFC) on Day 0 and Day 84 and tear break-up time (TBUT), ocular surface staining with fluorescein and lissamine green, tear meniscus evaluation, and visual acuity on Day 0, 35, and 84.

RESULTS

All VAS symptoms (except tingling/burning and sticky eye feeling), OSDI, CLEDQ-8, and DEFC showed statistically significant (p < 0.05) improvement from baseline (Day 0) to Day 84. Similarly, corneal (fluorescein) and conjunctival (lissamine green) quality improved during the study (p < 0.05 at Day 84 versus baseline). Tear break-up time (TBUT), conjunctival (lissamine green) staining, and tear meniscus decreased but the changes were not statistically significant. Visual acuity did not change during the study. There were no ocular or systemic adverse events.

CONCLUSIONS

This study showed that the instillation of a preservative-free, hypotonic, HA-Trehalose artificial tear in contact lenses wearers with dry eye syndrome significantly improved symptoms and reduced associated signs such as corneal and conjunctival staining.

Anwendungsmöglichkeiten der optischen Kohärenztomographie beim trockenen Auge

Durch die stetige Weiterentwicklung und Verbesserung der Technik hat die optische Kohärenztomographie (OCT) in den letzten Jahren neue Möglichkeiten zur Beurteilung der Strukturen des vorderen Augenabschnittes eröffnet. Aufgrund der Darstellung kleinster Strukturen, wie beispielsweise des Tränenfilms, nimmt die OCT in der Diagnostik und Verlaufsbeurteilung des trockenen Auges eine immer wichtigere Rolle ein. Der vorliegende Beitrag gibt einen Überblick über die derzeitigen Einsatzmöglichkeiten der OCT beim trockenen Auge.

A Randomized, Placebo-Controlled Phase II Clinical Trial of 0.01% or 0.02% Cyclosporin A with 3% Trehalose in Patients with Dry Eye Disease

Purpose: To compare the efficacy and safety of HU00701 (0.01% cyclosporin A + 3% trehalose), HU007 (0.02% cyclosporin A + 3% trehalose) (all w/v), and placebo in patients with moderate to severe dry eye disease (DED). Methods: This was a multicenter, randomized, double-masked, parallel, placebo-controlled phase II study. In total, 114 patients were randomly assigned to the HU00701, HU007, placebo, or reference group. There was a 2-week run-in period before the 12-week intervention. Efficacy and safety were evaluated every 4 weeks. Results: The primary endpoint, change in corneal staining score from baseline to week 12, did not differ significantly among the control, HU00701, and HU007 groups in the full analysis. Of the secondary endpoints, only the tear film breakup time differed significantly at week 12 between the placebo and HU00701 groups. Twenty adverse events were reported by 15 patients, but the rate did not differ significantly among the 4 groups. The laboratory test, vital signs, and physical examination data showed no significant changes during the study. Conclusions: HU00701 and HU007 are safe, and HU007 effectively reduces the corneal staining score in patients with moderate-to-severe DED (NCT02917512).

The Association between Tear Film Thickness as Measured with OCT and Symptoms and Signs of Dry Eye Disease: A Pooled Analysis of 6 Clinical Trials

Purpose: To determine the association between tear film thickness (TFT) as measured with ultra-high resolution optical coherence tomography (UHR-OCT) and signs and symptoms of dry eye disease (DED). Methods: A total of 450 eyes from 225 patients with DED from six different randomized clinical trials were included in this pooled analysis. In all subjects, TFT was measured with a custom-built UHR-OCT system. Symptoms of DED were quantified using a standardized Ocular Surface Disease Index (OSD)I questionnaire and clinical signs including tear film break up time (TFBUT) and Schirmer I test were assessed. Associations of the average TFT with OSDI, TFBUT, and Schirmer I test were calculated using a linear regression analysis. Results: The average TFT of the included sample (mean age, 45.0 ± 13.3 years; 65% female) was 4.2 ± 0.5 µm and the OSDI 36.2 ± 10.4. A significant negative correlation was found between TFT and OSDI (r = −0.36 to −0.31; p < 0.001). Tear break up time and Schirmer I test were not correlated with OSDI. Significant albeit weak correlations were found between TFT and TFBUT (r = 0.17 to 0.25; p < 0.01) as well as Schirmer I (r = 0.36 to 0.37; p < 0.001). Subgroup analysis revealed that the correlation was stronger in the subjects with abnormal Schirmer I (<15 mm; r = 0.50 to 0.54; p < 0.001). Conclusions: The present study demonstrates an objective measurement of TFT using a novel OCT approach for DED that correlates with symptoms and signs of DED. Our data are consistent with the idea that TFT represents the aqueous-deficient component of DED.

Short-Term Changes in Tear Lipid Layer Thickness After Instillation of Lipid Containing Eye Drops

Purpose

Lipid-containing eye drops is increasingly popular in eye clinics to treat dry eye. Tear lipid layer thickness (LLT) changes after instillation of lipid eye drops have not been characterized. We aim to evaluate these changes of LLT using a noninvasive interferometry-based method.

Methods

This prospective clinical study was conducted on staff and patients from Singapore National Eye Centre with ad hoc recruitment. Noninvasive tear break up time was measured using the Keratographer 5M. LLTs were measured using a tear interferometer machine before and at 1, 5, and 15 minutes after instillation of lipid-containing drops, either Cationorm unidose or Artelac Lipids. Fluorescein clearance (tear clearance rate) and Schirmer tests were conducted. The tear clearance rate of fluorescein dye was based on the visual examination of the color of a Schirmer strip after 5 minutes, compared against color standards.

Results

This study included a total of 84 participants aged ≥21 years. Many were female (92.8%) and Chinese (89.2%). A tear clearance rate of 1/16 was most common (35.7%), whereas 1/128 and 1/32 were uncommon (3.57% each). Schirmer results were 6.5 ± 8.1 mm, and noninvasive tear break up times were 8.12 ± 6.25 mm. Participants with baseline LLT <60 nm had greater changes in LLT after Cationorm instillation, compared with those with an LLT of >60 nm. LLT changes over 15 minutes were not associated with tear clearance rate. Similar results were obtained when using Artelac Lipids.

Conclusions

Our results showed that participants' initial LLT affected their responsiveness to lipid-containing eye drops more than other factors.

Translational Relevance

Doctors may choose to measure the baseline LLT of patients before deciding whether to prescribe lipid eye drops to patients.

Novel Approaches for Imaging-Based Diagnosis of Ocular Surface Disease

Imaging has become indispensable in the diagnosis and management of diseases in the posterior part of the eye. In recent years, imaging techniques for the anterior segment are also gaining importance and are nowadays routinely used in clinical practice. Ocular surface disease is often synonymous with dry eye disease, but also refers to other conditions of the ocular surface, such as Meibomian gland dysfunction or keratitis and conjunctivitis with different underlying causes, i.e., allergies or infections. Therefore, correct differential diagnosis and treatment of ocular surface diseases is crucial, for which imaging can be a helpful tool. A variety of imaging techniques have been introduced to study the ocular surface, such as anterior segment optical coherence tomography, in vivo confocal microscopy, or non-contact meibography. The present review provides an overview on how these techniques can be used in the diagnosis and management of ocular surface disease and compares them to clinical standard methods such as slit lamp examination or staining of the cornea or conjunctiva. Although being more cost-intensive in the short term, in the long term, the use of ocular imaging can lead to more individualized diagnoses and treatment decisions, which in turn are beneficial for affected patients as well as for the healthcare system. In addition, imaging is more objective and provides good documentation, leading to an improvement in patient follow-up and education.

New Technologies in Clinical Trials in Corneal Diseases and Limbal Stem Cell Deficiency: Review from the European Vision Institute Special Interest Focus Group Meeting

To discuss and evaluate new technologies for a better diagnosis of corneal diseases and limbal stem cell deficiency, the outcomes of a consensus process within the European Vision Institute (and of a workshop at the University of Cologne) are outlined. Various technologies are presented and analyzed for their potential clinical use also in defining new end points in clinical trials. The disease areas which are discussed comprise dry eye and ocular surface inflammation, imaging, and corneal neovascularization and corneal grafting/stem cell and cell transplantation. The unmet needs in the abovementioned disease areas are discussed, and realistically achievable new technologies for better diagnosis and use in clinical trials are outlined. To sum up, it can be said that there are several new technologies that can improve current diagnostics in the field of ophthalmology in the near future and will have impact on clinical trial end point design.

Trehalose for Ocular Surface Health

Trehalose is a natural disaccharide synthesized in various life forms, but not found in vertebrates. An increasing body of evidence demonstrates exceptional bioprotective characteristics of trehalose. This review discusses the scientific findings on potential functions of trehalose in oxidative stress, protein clearance, and inflammation, with an emphasis on animal models and clinical trials in ophthalmology. The main objective is to help understand the beneficial effects of trehalose in clinical trials and practice, especially in patients suffering from ocular surface disease. The discussion is supplemented with an overview of patents for the use of trehalose in dry eye and with prospects for the 2020s.

Topical Low Dose Preservative-Free Hydrocortisone Reduces Signs and Symptoms in Patients with Chronic Dry Eye: A Randomized Clinical Trial

PURPOSE

Dry eye disease (DED) is a highly prevalent ocular condition with a significant burden on affected patients. Regardless of the underlying etiology, DED is associated with increased ocular surface inflammation. We investigated the safety and efficacy of a short-term treatment with topical low dose hydrocortisone in patients with chronic DED and ocular surface inflammation.

METHODS

A total of 60 patients (mean age 51 ± 14 years) with chronic DED and conjunctival hyperemia greater than grade 2 on the Efron scale were included. Patients were randomized to receive either preservative-free hydrocortisone 0.335% (Softacort, Laboratories Thea, France) for 12 days four times daily followed by 2 days twice daily instillation (intense treatment group) or 8 days three times daily followed by 3 days twice daily treatment (standard treatment group). Ocular redness was assessed at baseline, day 14, and day 28. Measurement of intraocular pressure (IOP) and clinical tests to assess signs and symptoms of DED were performed.

RESULTS

Conjunctival hyperemia and Ocular Surface Disease Index (OSDI) significantly decreased in both treatment groups (p < 0.001 each) after hydrocortisone treatment. A significant increase in tear film thickness was seen 4 weeks after treatment start (p = 0.03 and p = 0.04, respectively). IOP did not change in either of the two treatment groups (p = 0.45).

CONCLUSION

Treatment with low dose hydrocortisone 0.335% reduced ocular inflammation and decreased OSDI score. No change in IOP was observed in either of the two treatment schedules. Because of its good safety profile, low dose hydrocortisone may be an interesting alternative to standard corticosteroid treatment in DED.

FUNDING

Laboratories Thea.

TRIAL REGISTRATION

Clinicaltrials.gov registry: NCT03907865.

Comparison study of two different topical lubricants on tear meniscus and tear osmolarity in dry eye

PURPOSE

To compare the effect of single-drop administration of two different ophthalmic solutions on tear meniscus and tear osmolarity in patients with mild to moderate dry eye disease.

METHODS

This prospective study comprised of 122 patients with mild to moderate dry eye disease. These patients received a single dose of either unpreserved trehalose 3%, hyaluronic acid 0.15%, carbomer 0.25% (THHA, Thealoz Duo Gel) (Group 1) or hyaluronic acid 0.3% (HA) (Group 2) gel-based lubricants. Tear meniscus (height and depth) were measured using anterior segment optic coherence tomography (AS-OCT) at baseline and 10, 60, 120, and 240 min. after instillation. Tear osmolarity, Schirmer I test, tear break-up time (TBUT), gel properties, and patient comfort were evaluated 240 min. after instillation.

RESULTS

Tear meniscus height (TMH) and tear meniscus depth (TMD) showed a significant increase with both lubricants compared to the baseline (p < 0.001). This effect remained significant for up to 60 min. and 120 min. for the THHA and HA 0.3% solutions, respectively (p < 0.05, for both). Mean comfort duration was 115.1 ± 20.1 min. in Group 1 and 148.3 ± 49.0 min in Group 2 (p < 0.001). Tear osmolarity, Schirmer I test, and TBUT were similar between the baseline and 240 min. for each group.

CONCLUSIONS

The results of this study demonstrate that 0.3% HA remains on the ocular surface for longer than TH-HA. The longer ocular residency time also seems to correlate with a longer patient comfort duration.

Automatic assessment of tear film and tear meniscus parameters in healthy subjects using ultrahigh-resolution optical coherence tomography

Many different parameters exist for the investigation of tear film dynamics. We present a new tear meniscus segmentation algorithm which automatically extracts tear meniscus area (TMA), height (TMH), depth (TMD) and radius (TMR) from UHR-OCT measurements and apply it to a data set including repeated measurements from ten healthy subjects. Mean values and standard deviations are 0.0174 ± 0.007 mm², 0.272 ± 0.069 mm, 0.191 ± 0.049 mm and 0.309 ± 0.123 mm for TMA, TMH, TMD and TMR, respectively. A significant correlation was found between all respective tear meniscus parameter pairs (all p < 0.001, all Pearson's r ≥ 0.657). Challenges, limitations and potential improvements related to the data acquisition and the algorithm itself are discussed. The automatic segmentation of tear meniscus measurements acquired with UHR-OCT might help in a clinical setting to further understand the tear film and related medical conditions like dry eye disease.

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.

Efficacy and safety of glycyrrhizin 2.5% eye drops in the treatment of moderate dry eye disease: results from a prospective, open-label pilot study

Background

Dry eye disease (DED) is characterized by a loss of homeostasis of the tear film. It goes along with ocular symptoms, in which ocular surface inflammation and damage play etiological roles. High-mobility group box 1 protein (HMGB1) is a pro-inflammatory protein found in the tear fluid during conjunctivitis, blepharitis and DED. Glycyrrhizin binds to HMGB1, inhibiting cytokine activities, thus potentially improving DED.

Aim

To assess the efficacy and tolerance of glycyrrhizin in moderate DED.

Methods

Multicenter, open-label, prospective, nonrandomized clinical pilot study of glycyrrhizin 2.5% eye drops twice daily over 28 days in adult patients with moderate DED using standard evaluation parameters.

Results

The overall mean age of the 37 patients included was 59.6±19.0 years, 70.3% of the patients were female and 77.0% of the patients had an Oxford score of II. After 28 days, 60.8% of the patients had an Oxford score of 0 or I; a significant mean improvement in the score of 0.97±0.86 (P<0.001) from 2.20±0.44 at day 1 to 1.23±0.88 at day 28 was observed. Tear break-up time and Schirmer scores had significantly improved while the number of patient-reported symptoms had significantly decreased (all P≤0.010). A large majority of patients still had a few spots on their naso-bulbar conjunctiva (86.1%), temporal-bulbar conjunctiva (81.4%) and cornea (84.7%). The investigators considered that DED had improved in 71.6% of the patients. Patients appreciated the eye drops for their efficacy and good tolerance profile, leading to a decreased use of artificial tears. No changes in intraocular pressure and visual acuity were observed; glycyrrhizin 2.5% eye drops were safe, with only one patient reporting a moderate, transient treatment-related contact allergy leading to the withdrawal of the patient. Overall, two patients reported three adverse events, two (moderate contact allergy in both eyes) were related to the eye drops and experienced by the same patient; treatment was stopped; the third event was not treatment-related.

Conclusion

In this pilot study, glycyrrhizin 2.5% eye drops were well tolerated and provide a good clinical benefit to patients with moderate DED after 28 days of continued daily use.

Intense regulated pulse light for the meibomian gland dysfunction

PURPOSE

To assess the effect of intense regulated pulse light (E-Eye; E-Swin, France) on the treatment of meibomian gland dysfunction.

SETTING

Health Sciences University, Ankara Numune Training and Research Hospital, Department of Ophthalmology.

METHODS

A total of 26 patients underwent intense pulsed light treatment (E-Eye; E-Swin), with homogeneously sequenced five light pulses delivered to one eye at 1, 15, and 45 days following baseline evaluation. At each visit, subjective clinical parameters (ocular surface disease index questionnaire and standard patient evaluation of eye dryness questionnaire) and objective clinical parameters (Schirmer I test scores, tear break-up times, Oxford grading, lid margin abnormality score, secretion quality and expressibility degree) were recorded. The subjective and objective parameters at Days 15 and 45 were compared with baseline values.

RESULTS

Patients underwent three sessions of intense pulsed light treatment. Schirmer test and tear break-up time improved significantly from baseline to Day (D) 45 (8.53 ± 4.31 mm vs 12.6 ± 3.14 mm, 4.53 ± 1.33 sn vs 11.07 ± 2.87 sn, p = 0.003 and p < 0.001). Ocular surface disease index and standard patient evaluation of eye dryness scores improved from baseline to D15 and baseline to D45 (all with p < 0.05). All the subjects reported reduced symptoms by D45. There were no cases of adverse ocular effects. There was no significant change in Oxford grading, lid margin abnormality score, secretion quality, and expressibility degree.

CONCLUSIONS

Intense regulated pulse light seems a safe treatment procedure for meibomian gland dysfunction, improving tear film quality and reducing symptoms of dry eye.

Effect of Single Instillation of Two Hyaluronic Acid-Based Topical Lubricants on Tear Film Thickness in Patients with Dry Eye Syndrome

PURPOSE

This study investigated the effect of single administration of 2 different hyaluronic acid-based topical lubricants on tear film thickness (TFT) in patients with moderate-to-severe dry eye disease (DED).

METHODS

Sixty patients were randomized to receive eye drops containing unpreserved sodium hyaluronate, triglycerides, and phospholipids (HTP), unpreserved sodium hyaluronate (HA), or unpreserved sodium chloride (NaCl). TFT and lipid layer thickness (LLT) were assessed before and at defined time points after single instillation with a custom-built ultrahigh-resolution optical coherence tomography system and a white light interferometer. Standard tests for DED such as a visual analogue scale (VAS), corneal fluorescein staining (CFS), Schirmer I test, and tear break-up time (BUT) were performed.

RESULTS

The time course in TFT was significantly different between the 3 administered agents (P < 0.001). Single administration of HTP significantly increased TFT over a period of 40 min, an increase in TFT over 20 min was observed after instillation of HA, whereas NaCl had no effect. No significant difference in the change in BUT, CFS, or LLT was observed between the 3 groups (P = 0.57, 0.97, and 0.86, respectively). A significant improvement in subjective symptoms (VAS) was found after single instillation of HTP (P = 0.03 vs. baseline) and HA, but not after administration of NaCl (P = 0.03, P < 0.01, and P = 0.08 vs. baseline, respectively, P = 0.57 between groups).

CONCLUSIONS

Single administration of HTP and HA significantly increased TFT showing a longer residence time and improved subjective symptoms, whereas instillation of NaCl had no effect. Long-term studies with multiple instillations will be necessary to further investigate the effect of the tested products on the clinical outcome. ClinicalTrials.gov ID: NCT03161080.

Anterior segment optical coherence tomography: its application in clinical practice and experimental models of disease

Optical coherence tomography (OCT) provides non-invasive, high-resolution in vivo imaging of the ocular surface and anterior segment. Over the years, it has become an essential tool for evaluating the anterior segment of the eye to monitor ocular development and ocular pathologies in both the clinical and research fields of ophthalmology and optometry. In this review, the clinical applications relating to the use of anterior segment OCT for imaging and quantifying normal and pathological features of the ocular surface, cornea, anterior chamber, and aqueous outflow system are summarised in a range of human ocular diseases. Applications of anterior segment OCT technology that have improved imaging and quantitation of ocular inflammation in experimental animal models of ocular diseases, such as anterior uveitis, microbial keratitis and glaucoma, are also described. The capacity to longitudinally evaluate anterior segment anatomical changes during development, and inflammation facilitates the understanding of the dynamics of tissue responses, and further enhances the intra-operative in vivo imaging during procedures, such as corneal transplantation and drug delivery. Future developments including in vivo ultrahigh-resolution anterior segment OCT, automated analyses of anterior segment OCT images and functional extensions of the technique, may revolutionise the clinical evaluation of anterior segment, corneal and ocular surface diseases.

Ocular surface lubricants

PURPOSE OF REVIEW

The purpose of this article is to provide an overview of the ocular lubricants currently available, consider the components of the various formulations and highlight the status of preservative use in the treatment of anterior ocular surface diseases.

RECENT FINDINGS

The primary components of ocular surface lubrication have been, in the past, based on various cellulose formulations that increase hydration. Advances in lubrication have come from areas of the human body requiring lubrication such as the skeletal joints as well as examining the use of natural components of the tear fluid. These have resulted in novel modifications of existing tear components, for example, thiolated carboxymethyl hyaluronic acid which creates crosslinking to mechanically increase retention time for ocular surface hydration. Other proteoglycans such as lubricin, having one of the lowest coefficients of friction in nature, to a lipopolysaccharide derivative of tamarind seed, may provide a unique delivery system for lubricants and medications.

SUMMARY

The present state of ocular surface lubrication is slowly advancing from the routine use of cellulose-based solutions and gels to more advanced replacement with natural tear components. The advances that are occurring on other lubricating surfaces of the musculoskeletal system are also providing some insights into potential use on the ocular surface.

Effect of changing from preserved prostaglandins to preservative-free tafluprost in patients with glaucoma on tear film thickness

PURPOSE

Long-term glaucoma therapy with preservative-containing eye drops may impact ocular surface health. This study was performed to investigate whether a switch from preserved topical prostaglandin therapy to preservative-free tafluprost therapy improves precorneal tear film thickness in patients with glaucoma or ocular hypertension.

METHODS

A total of 30 patients who were under topical preservative-containing prostaglandin monotherapy for at least 6 months were included. Patients were then switched from preserved prostaglandin therapy to unpreserved tafluprost drops once daily. Tear film thickness was measured at baseline and 4 and 12 weeks after therapy change with an ultrahigh-resolution optical coherence tomography system. Furthermore, clinical measures of ocular surface disease were determined and symptoms were assessed using the Dry Eye-Related Quality-of-Life Score.

RESULTS

After switching to unpreserved tafluprost, tear film thickness significantly increased from 4.7 ± 0.5 to 5.0 ± 0.6 µm 4 weeks after therapy change and still tended to be increased after 12 weeks (4.8 ± 0.7 µm). Breakup time significantly increased from 5.1 ± 2.3 to 7.2 ± 3.4 s and to 10.1 ± 3.6 s after therapy change. In addition, a significant decrease in corneal staining score from 1.8 ± 0.7 to 1.4 ± 0.8 after 4 weeks and to 0.7 ± 0.7 after 12 weeks treatment was observed. Switching to preservative-free drops reduced Dry Eye-Related Quality-of-Life Score from 11.4 ± 11.0 to 5.7 ± 6.4 and to 4.7 ± 7.5.

CONCLUSION

Our data show that switching to preservative-free tafluprost leads to an increase in tear film thickness, breakup time, and an improvement of Dry Eye-Related Quality-of-Life Score. Our results therefore indicate that a switch to unpreserved tafluprost is beneficial for ocular surface health in patients under long-term preserved prostaglandin eye drops.