Tear Film Osmolarity, Ocular Surface Disease and Glaucoma: A Review

Evaluation of therapeutic efficacy of Emustil drops for ocular discomfort and tear film osmolarity using different treatment management modes under dry environmental conditions

BACKGROUND

We aimed to check the efficacy of Emustil (oil in water emulsion) drops on tear film index and ocular surface dynamics in dry environments through protection and relief treatment modalities.

METHODS

The subjects were exposed to a dry environment using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the temperature was 21 °C and screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST) and tear production using ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620 and Schirmer strips/phenol red test respectively. Tear production was calculated by the Tear Function Index test (TFI).

RESULTS

The mean tear film osmolarity decreased significantly from 296.8 mOsm/l at 40% RH to 291 mOsm/l at 5%. (p = 0.01). Instillation of Emustil resulted in a significant increase in tear osmolarity in the relief method compared with osmolarity seen at 5% RH when no drop was used. The mean PRT value decreased from 26 ± 9 in normal conditions (40% RH) to 22 ± 4 mm in dry conditions (5% RH). Emustil drops did not induce any significant change in tear production in the PRT test. No significant change was found in OST following exposure to 5% RH. OST did not show a statistically significant change with the emulsion when used for relief (p > 0.05). The mean score of ocular discomfort observed was 70 at 5% RH. Still, the instillation of the oil-in-water emulsion (Emustil) resulted in a noticeable decrease in visual discomfort to 37 (p = 0.00) in protection and 59 in relief (p = 0.05). Emustil drops substantially improved tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, tear production was improved.

CONCLUSION

CEC allows for a thorough evaluation of tear film parameters and dry eye treatment protocols in labs, providing greater confidence when applying them to patients. In addition, our study showed that Emustil not only provides protection and relief for dry eyes but also helps to maintain ocular homeostasis in desiccating environments. This indicates a promising potential for improving dry eye treatment protocols.

FAST® questionnaire for identifying glaucoma patients at risk for ocular surface disease

OBJECTIVES

To evaluate the validity and reliability of the new Fast Assessment of the Ocular Surface Trouble (FAST®) questionnaire for identifying glaucoma or ocular hypertension (OHT) patients at risk of ocular surface disease (OSD).

METHODS

A multicenter, international, cross-sectional, epidemiological survey evaluated the most accurate interview items and ocular signs on the initial 14-item version of FAST® to develop a shorter version for routine, quick clinical use. Rasch analysis and least absolute shrinkage and selection operator (LASSO) method was used to reduce the number of items on the questionnaire. Sensitivity and specificity of FAST® were assessed with receiver operating characteristic (ROC) curves for the detection of OSD with the questionnaire and ophthalmic assessment.

RESULTS

A total of 2308 eyes (1154 patients) were analyzed in this study by 92 ophthalmologists. The initial version of the FAST® indicated 60% of the subjects had OSD. Rasch analysis allowed removal of some clinical signs. The LASSO method allowed elimination of some items from the original questionnaire for a 9-item and a 6-item version of FAST®. For the 6-item questionnaire, the sensitivity and specificity were 71.9% and 74.3% respectively and the area under the curve was 0.815.

CONCLUSIONS

The FAST® questionnaire is a valid and reliable tool for use in routine clinical practice and in clinical trials. The short versions of the questionnaire allow quick detection of the majority of patients with OHT or glaucoma at risk of dry eye.

Effectiveness of a New Active Tear Substitute Containing 0.2% Hyaluronic Acid and 0.001% Hydrocortisone on Signs and Symptoms of Dry Eye Disease by Means of Low- and High-Tech Assessments

INTRODUCTION

An innovative eye drops formulation containing 0.2% hyaluronic acid and a low concentration of hydrocortisone (0.001%; hereafter HALH) has been recently placed on the market (Idroflog®, Alfa Intes, Italy) to manage the dysregulated parainflammation in patients with dry eye disease (DED). In the present paper, the effectiveness of HALH on the signs and symptoms of DED was retrospectively evaluated and compared with that one obtained using standard tear substitutes (STS) by means of low- and high-tech (Keratograph®) assessments.

METHODS

This was a multicenter retrospective study carried out between February and April 2023, involving adult patients with DED diagnosis owing to post-cataract surgery, meibomian gland dysfunction, allergy, or glaucoma medications. The primary aim was to compare the changes induced by different therapies on Keratograph® parameters (noninvasive Keratograph tear breakup time [NIKBUT], tear meniscus height [TMH], eyelid meibography, conjunctival hyperemia, and conjunctivochalasis) or collected by traditional low-tech measures (tear breakup time [TBUT], Schirmer test, Efron score, and epithelial alterations) and the Ocular Surface Disease Index score.

RESULTS

Data from 155 patients were analyzed. The effectiveness of HALH and STS was reported by both high- and low-tech measures. NIKBUT-first showed a significant improvement in the HALH group versus the STS one at 15 days (6.4 ± 3.6 vs 5.4 ± 3.7 s, p = 0.02), whereas this difference was latent with low-tech TBUT until 45 days (6.8 ± 2.6 vs 5.6 ± 2.3 s, p = 0.03). Patients with DED occurring after cataract surgery reported an enhanced activity of HALH versus STS, particularly for NIKBUT-first, TMH, Schirmer test, and hyperemia stage.

CONCLUSION

These findings highlighted the effectiveness of HALH in all DED subtypes, especially in patients with post-cataract surgery, as well as its superiority versus STS in terms of tear film stability improvement. We recommend longer observation (i.e., 3-6 months) to fully ascertain whether the early improvement detected by high-tech measures will be confirmed in subsequent time points even using low-tech tests.

Efficacy of Topical 0.05% Cyclosporine A for Ocular Surface Disease Related to Topical Anti-Glaucoma Medications

Purpose: We aimed to determine the therapeutic efficacy of 0.05% topical cyclosporine A (CsA) for chronic ocular surface disease (OSD) in patients using benzalkonium chloride (BAK)-preserved antiglaucoma eye drops. Methods: A prospective, randomized, paired-eye, controlled clinical trial was conducted with participants who had been instilling at least one BAK-preserved topical antiglaucoma drug in both eyes for at least 6 months. Topical CsA was only applied in randomly selected unilateral eyes. Visual field (VF) indices, ocular surface parameters, tear meniscus height (TMH), and matrix metalloproteinase-9 (MMP-9) immunoassay were evaluated at baseline and at 2 and 4 months. Results: Seventy eyes from 35 participants were included in the study. The Schirmer I, tear breakup time, and TMH increased by 4.5 ± 8.6 mm (P < 0.01), 5.0 ± 5.3 s (P < 0.001), and 85.4 ± 159.0 μm (P < 0.01) in the treated eyes at 4 months from baseline, respectively. The ocular staining score and MMP-9 positivity in the treated eyes decreased by 2.2 ± 1.3 (P < 0.001) and 0.7 ± 0.9 points (P < 0.001), respectively, at 4 months. In untreated eyes, only TMH increased by 41.4 ± 92.1 μm (P = 0.016) from baseline to 4 months. In VF indices, the tracking failure frequency was 19.09% ± 21.62%, and the test duration was 336.0 ± 79.5 s in the treated eyes at 4 months, which were lower than 34.37% ± 23.13% (P < 0.001) and 375.9 ± 70.7 s (P < 0.05) in the nontreated eyes. Conclusion: Application of topical 0.05% CsA significantly improved the OSD parameters and the reliability indices of VF tests. This study was registered with the Clinical Research Information Service (CRIS) (number KCT0007124).

Factors influencing the effectiveness of trabeculectomy: following materials of the City Multidisciplinary Hospital No. 2

BACKGROUND: Despite the ever-expanding arsenal of IOP-lowering surgeries, trabeculectomy remains the most common procedure amongst them. Therefore, the identification of factors reducing its effectiveness and potentially being able to change the surgical treatment plan is of particular importance. AIM: To identify factors reducing trabeculectomy effectiveness. MATERIALS AND METHODS: The study group consisted of 443 consecutively enrolled patients who were operated in 20162020 in Saint Petersburg City Multidisciplinary Hospital No. 2 for primary open-angle decompensated glaucoma and then observed for 6 to 24 months. Using statistical research methods, factors that significantly affected the impact of the procedure were identified. RESULTS: The main predictors of trabeculectomy failure following the order of decreasing importance of established relations (p) were: loss of effectiveness of the preceding IOP-lowering procedure (р = 0.0001), dry eye syndrome (р = 0.013), number of drop instillations per day (р = 0.041), and excessive preservative load due to unnecessarily aggressive topical glaucoma treatment (р = 0.039). An obvious demonstration of excessive therapy is a simultaneous administration of four IOP-lowering medications. It also causes scarring of the procedure area, especially in patients previously operated for glaucoma. Null preservative load and prostaglandin monotherapy are associated with guaranteed complete success of trabeculectomy. Unlike the intensity of medical glaucoma treatment, its duration does not have such a significant impact on trabeculectomy outcomes (р = 0.270). Close to a significant one is the relationship between poor surgical outcomes and advanced stages of the disease (р = 0.052). CONCLUSIONS: The main factors affecting the effectiveness of trabeculectomy were failure of the previous IOP-lowering surgeries; concomitant dry eye syndrome, arising or being aggravated by unduly intense and prolonged pharmacological effects on the eye surface; as well as delayed appliance for surgical IOP normalization at advanced disease stages.

A novel ophthalmic latanoprost 0.005% nanoemulsion: a cytotoxicity study

BACKGROUND

Benzalkonium chloride (BAK), the most commonly used preservative in anti-glaucoma eye drops, inflicts damage to the ocular surface. A novel anti-glaucoma formulation that avoids the use of BAK has been developed. The aim of this study was to evaluate the cytotoxicity of this formulation and to compare it with an ophthalmic solution containing BAK.

METHODS

Two different latanoprost eye drops were used: one ophthalmic solution (LSc) containing BAK 0.02% and one ophthalmic nanoemulsion (LNe) with a soft preservative (potassium sorbate 0.18%). Human epithelial conjunctival cells were incubated for 15, 30, and 60 min with either LSc or LNe. The cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V-FITC and propidium iodide.

RESULTS

The values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to the control group, whereas values obtained from cells exposed to LSc were around 30% at all study times (p < 0.05 at 15 and 30 min; p < 0.01 at 60 min). The percentage of viable cells decreased significantly when cells were incubated with LSc compared with cells incubated with LNe at all the study times, while the percentage of cells in late apoptosis/necrosis increased significantly in cells exposed to LSc compared to LNe.

CONCLUSIONS

The new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. These results suggest that the new formulation might be gentler on the eye surface than currently available BAK-preserved latanoprost solutions.

Anti-glaucoma agents-induced pseudodendritic keratitis presumed to be herpetic simplex keratitis: a clinical case series

Anti-glaucoma agents-induced corneal toxicity may be misdiagnosed as herpetic simplex keratitis (HSK). In our study, nineteen glaucoma patients were presumed to have HSK before referral. Corneal lesions were classified into (I) linear pseudodendritic lesions formed by elevated opacified cells, (II) linear pseudodendritic lesions formed by grouped superficial punctate keratitis (SPK), (III) satellite full-thickness epithelial defects, (IV) satellite lesions formed by elevated opacified cells, and (V) geographic lesions formed by grouped SPK. We observed thirty-one events, with 15 in the lower and 16 in the central corneas. There were 21 (67.7%) type II, five (16.1%) type V, two (6.5%) of each for types III and IV, and one (3.2%) type I events. Among linear lesions (types I and II), 17 (77.3%) had horizontal and 5 (22.7%) had curvilinear orientations. Exposure duration to the last-added anti-glaucoma agent was three days to 14.5 years. About half of the events (16/31, 51.6%) used prostaglandin analogues, and 30/31 (96.8%) applied benzalkonium chloride (BAK)-containing agents. All lesions resolved within two months after decreasing offending medications or enhancing protection of ocular surface. In conclusion, anti-glaucoma agents-induced pseudodendritic keratitis presents majorly in central-lower cornea as horizontally linear lesions, and BAK-containing agents are observed in the most events.

Evaluation of lacrimal drainage system in Pseudoexfoliation syndrome

Purpose

To evaluate the prevalence of the obstruction of lacrimal drainage system (LDS) in patients with pseudoexfoliation (PXF) syndrome.

Materials and Methods

This cross-sectional study included 152 eyes of 76 consecutive patients with bilateral PXF syndrome and 170 eyes of 85 age and gender-matched controls. The LDS evaluation was performed based on dye disappearance test, slit-lamp examination, diagnostic probing, and irrigation test. The presence of punctal stenosis and canalicular obstruction were considered as the obstruction of proximal LDS; and complete or incomplete nasolacrimal duct obstruction was considered as obstruction of distal LDS. Demographic characteristics, ophthalmologic findings, and prevalence and site of obstruction of LDS were compared among the groups.

Results

The prevalence of obstruction of LDS was higher in the PXF syndrome group when compared to controls (21.1% vs 12.2%), but the difference was not statistically significant (p = 0.061). The obstruction of proximal LDS was found to be more frequent in the PXF syndrome (17.7%) group when compared to controls (10.0%), and this difference was statistically significant (p = 0.041). There was significantly more punctal stenosis in the PXF syndrome group when compared to controls (15.1% vs 7.6%, p = 0.033). The prevalence of canalicular stenosis and obstruction of distal LDS was similar in the PXF and the control groups (p = 0.596 and p = 0.741, respectively).

Conclusion

The prevalence of punctal stenosis was statistically significantly higher in the PXF syndrome group when compared to the controls. This association is probably related to increased local ocular surface inflammation which is triggered by the accumulation of PXF material.

Changes in peri-ocular anatomy and physiology in pseudoexfoliation syndrome (Review)

Pseudoexfoliation syndrome (PEX) is characterized by the deposition of proteinaceous material in the anterior ocular segment (resulting in ophthalmic pathologies such as glaucoma and increased risk of complications in cataract surgery), but also by several systemic manifestations. The involvement of peri-ocular tissues in PEX, including the eyelid skin, lacrimal gland, conjunctiva, orbital fat and vessels, as well as the optic nerve, has been reported by several previous studies. The peri-ocular effects of PEX include the development of eyelid laxity, conjunctival chalasis, tear film abnormalities, pronounced orbital fat atrophy in response to the administration of prostaglandin analogues in pseudoexfoliative glaucoma, deficient orbital vascular supply and biomechanical changes in both the eyeball and the optic nerve. These effects may have important clinical implications, including increased difficulty in cataract surgery, ocular surface disease and eyelid margin malpositions.

Mitochondrial Dysfunctions May Be One of the Major Causative Factors Underlying Detrimental Effects of Benzalkonium Chloride

Benzalkonium chloride (BAC) is currently the most commonly used antimicrobial preservative in ophthalmic solutions, nasal sprays, and cosmetics. However, a large number of clinical and experimental investigations showed that the topical administration of BAC-containing eye drops could cause a variety of ocular surface changes, from ocular discomfort to potential risk for future glaucoma surgery. BAC-containing albuterol may increase the risk of albuterol-related systemic adverse effects. BAC, commonly present in personal care products, in cosmetic products can induce irritation and dose-dependent changes in the cell morphology. The cationic nature of BAC (it is a quaternary ammonium) suggests that one of the major targets of BAC in the cell may be mitochondria, the only intracellular compartment charged negatively. However, the influence of BAC on mitochondria has not been clearly understood. Here, the effects of BAC on energy parameters of rat liver mitochondria as well as on yeast cells were examined. BAC, being a "weaker" uncoupler, potently inhibited respiration in state 3, diminished the mitochondrial membrane potential, caused opening of the Ca2+/Pi-dependent pore, blocked ATP synthesis, and promoted H₂O₂ production by mitochondria. BAC triggered oxidative stress and mitochondrial fragmentation in yeast cells. BAC-induced oxidative stress in mitochondria and yeast cells was almost totally prevented by the mitochondria-targeted antioxidant SkQ1; the protective effect of SkQ1 on mitochondrial fragmentation was only partial. Collectively, these data showed that BAC acts adversely on cell bioenergetics (especially on ATP synthesis) and mitochondrial dynamics and that its prooxidant effect can be partially prevented by the mitochondria-targeted antioxidant SkQ1.