The Contribution of Meibomian Disease to Dry Eye

Assessment of tear-evaporation rate in thyroid-gland patients

Objective

To assess the tear-evaporation rate in thyroid-gland patients using a VapoMeter.

Methods

Twenty thyroid gland patients aged 18-43 years (mean 34.3±6.3 years) completed the study. Additionally, an age-matched control group of 20 patients aged 18-43 years (32.2±5.1 years) was enrolled in the study for comparison purposes. An Ocular Surface Disease Index dry-eye questionnaire was completed, followed by a test to determine the tear-evaporation rate using the VapoMeter. The test was performed three times per subject by the same examiner. Two readings were obtained each time.

Results

Significant differences (P<0.05) were found between mean Ocular Surface Disease Index and tear-evaporation-rate scores within the study and control groups. The average tear-evaporation rate was much higher in the study group (median 41.2 [IQR 41.4] g/m²⋅h) than the control group (15.7 [13.7] g/m²⋅h). Moreover, the average Ocular Surface Disease Index score for thyroid-gland patients was much higher (15.6 [23.4]) compared to the control group (5.5 [7.50]).

Conclusion

The tear-evaporation rate in thyroid-gland patients was found to be much higher than normal-eye subjects.

Hypoxia: A breath of fresh air for the meibomian gland

PURPOSE

Optimal meibomian gland (MG) function is critically important for the health and wellbeing of the ocular surface. We hypothesize that low oxygen (O₂) conditions promote the function of human MG epithelial cells (HMGECs) and that human MGs exist in a relatively hypoxic environment. The purpose of this study was to test our hypotheses.

METHODS

We used human and mouse eyelid segments, and immortalized human MG epithelial cells (IHMGECs) in our studies. To evaluate oxygen (O₂) levels in the mouse MG and vicinity, we injected pimonidazole (pimo), a hypoxia marker, before sacrifice. Human eyelid samples were stained with the hypoxia marker glucose transporter 1 (Glut-1). To determine the effect of low O₂ levels on IHMGECs, we cultured cells under proliferating and differentiating conditions in both normoxic (21% O₂) and hypoxic (3% O₂) conditions for 5-15 days. IHMGECs were evaluated for cell number, neutral lipid content, lysosome accumulation, expression of biomarker proteins and DNase II activity.

RESULTS

Our results demonstrate that human and mouse MGs, but not the surrounding connective tissue, exist in a relatively hypoxic environment in vivo. In addition, our findings show that hypoxia does not influence IHMGEC numbers in basal or proliferating culture conditions, but does stimulate the expression of SREBP-1 in differentiating IHMGECs. Hypoxia also significantly increased DNase II activity, and apparently IHMGEC terminal differentiation.

CONCLUSIONS

Our Results support our hypotheses, and indicate that relative hypoxia promotes MG function.

Perioperative Ocular Parameters Associated With Persistent Dry Eye Symptoms After Cataract Surgery

PURPOSE

To evaluate perioperative dry eye (DE) syndrome and meibomian gland dysfunction (MGD) parameters associated with persistent DE symptoms after cataract surgery.

METHODS

We enrolled patients who underwent uncomplicated cataract surgery without previous ocular comorbidities and previous use of ophthalmic treatment except for artificial tears at a single tertiary hospital. Lipid layer thickness, meibomian gland (MG) dropout, tear breakup time, Oxford staining score, lid margin abnormality, meibum quality, meibum expressibility, MG orifice obstruction, MGD stage, Ocular Surface Disease Index (OSDI), and Schirmer test score were prospectively assessed in order at baseline and 1 and 3 months postoperative. Patients with an OSDI score >12 at 3 months postoperative were defined as patients with persistent DE symptoms after cataract surgery. Multivariate logistic regression was then used to determine risk factors for persistent DE symptoms.

RESULTS

A total of 116 eyes of 116 patients were enrolled, and 96 patients completed all examinations until 3 months postoperative. Thirty-one patients had persistent DE symptoms at 3 months postoperative. The Oxford staining score, lid margin abnormality, meibum quality, and MGD stage were improved over time. Baseline high OSDI scores [odds ratio (OR), 1.072; P = 0.001] and 1 month postoperative low tear breakup time, low MG orifice obstruction scores, and increased MG dropout (OR, 0.322; P < 0.001, OR, 0.291; P = 0.015, OR, 1.145; P = 0.007, respectively) were determined as risk factors for persistent DE symptoms after cataract surgery.

CONCLUSIONS

Ocular parameters at baseline and at 1 month postoperative were important in predicting persistent DE symptoms after cataract surgery.

The Effect of Solithromycin, a Cationic Amphiphilic Drug, on the Proliferation and Differentiation of Human Meibomian Gland Epithelial Cells

PURPOSE

We previously discovered that azithromycin (AZM) acts directly on immortalized human meibomian gland epithelial cells (IHMGECs) to stimulate their lipid and lysosome accumulation and overall differentiation. We hypothesize that this phospholipidosis-like effect is due to AZM's cationic amphiphilic drug (CAD) nature. If our hypothesis is correct, then other CADs (e.g., solithromycin [SOL]) should be able to duplicate AZM's action on IHMGECs. Our purpose was to test this hypothesis.

MATERIALS AND METHODS

IHMGECs were cultured in the presence of vehicle or SOL (2, 10, or 20 µg/ml) for up to 7 days under proliferating or differentiating conditions. Positive (epidermal growth factor and bovine pituitary extract for proliferation; AZM for differentiation) and negative (vehicle) controls were included with the experiments. IHMGECs were evaluated for cell number, neutral lipid content, and lysosome accumulation.

RESULTS

Our results demonstrate that SOL induces a rapid and dose-dependent increase in the accumulation of neutral lipids and lysosomes in HMGECs. The lysosomal effects were most prominent with the 10 and 20 µg/ml doses, and occurred earlier (i.e., 1 day) with SOL than with the AZM (10 µg/ml) control. The effects of SOL and AZM on IHMGEC differentiation were essentially the same after 3 days of culture. SOL did not influence the proliferation of HMGECs during a 7-day time period.

CONCLUSIONS

Our results support our hypothesis that SOL, a CAD, is able to reproduce AZM's impact on lysosome and lipid accumulation, as well as the differentiation, of HMGECs. The effect of SOL on lysosome appearance was faster than that of AZM.

Meibomian Glands and Ocular Surface Changes After Closure of Meibomian Gland Orifices in Rabbits

PURPOSE

To investigate changes in the corneal surface, tear film, and meibomian glands after meibomian gland orifice closure.

METHODS

Seventy-two eyes of 36 rabbits were used. In the study group (n = 36), the meibomian gland orifices of both upper and lower eyelids in the right eyes were electrosurgically coagulated. The 36 untreated left eyes were used as controls. Corneal wetting properties were measured 1, 3, 7, and 14 days after coagulation. The eyelid sections were stained with anti-cytokeratin (CK)1, CK5, and CK6 antibody 8 weeks after coagulation. The area of the secretory acini around one meibomian gland duct was measured, and meibography of rabbits was performed 8 weeks after meibomian gland orifice closure.

RESULTS

Three days after coagulation, the corneal wetting property was decreased compared with controls. The meibomian gland ducts gradually dilated in the study group over time. The epithelium of the central ducts in both groups was stained with CK5 and CK6, but not CK1. Although the mean area of the secretory acini in the study group (0.10 ± 0.04 mm) was significantly smaller than that of the control group (0.18 ± 0.04; P = 0.004), meibography showed normal morphology in both study and control groups.

CONCLUSIONS

Meibomian gland orifice closure reduced corneal wetting property and induced meibomian gland duct dilation accompanied by shrinkage of secretory acini. Meibography could not detect early changes in the meibomian gland after closure of the orifice. Therefore, when the orifice is obstructed, more active treatments are needed before structural changes occur.

The function and morphology of Meibomian glands in patients with thyroid eye disease: a preliminary study

BACKGROUND

To investigate function and morphology of the meibomian gland (MG) in patients with thyroid eye disease (TED).

METHODS

In this prospective case series study, patients with unilateral or bilateral TED were consecutively enrolled. The diagnosis of TED was based on the typical orbital findings and/or radiographic evidence. The disease activity of TED was classified according to the clinical activity score (CAS). Degrees of lagophthalmos and exophthalmos, blinking rates, and results of the Schirmer test 1 were also recorded. All patients completed the SPEED questionnaire and underwent MG assessment, including lipid layer thickness (LLT), MG dropout (MGd), and MG expression.

RESULTS

In total 31 eyes from 17 patients with unilateral or bilateral TED were included. Patients were divided into inactive TED (CAS 0-1; 20 eyes from 11 patients) and active TED (CAS 2-3, 11 eyes from 6 patients) groups. MGd was significantly more severe in the active TED than the inactive TED group [Median (Inter-quartile region): 3.0 (2.0-3.0) vs. 2.0 (1.0-2.0) degree, P = 0.04]. However, patients with active TED had thicker LLT than those with inactive TED (90.0 [80.0-100.0] vs. 65.0 [47.8-82.5] nm, P = 0.02), and LLT was positively correlated with lagophthalmos (r = 0.37, P = 0.04).

CONCLUSIONS

Patients with active TED had more severe MGd, but thicker LLT. Active TED may cause periglandular inflammation of MGs, leading to MGd, but compensatory secretion from residual MGs and lagophthalmos-induced forceful blinking might temporarily release more lipids over the tear film.

A novel system, TearCare®, for the treatment of the signs and symptoms of dry eye disease

PURPOSE

The objective of this study was to evaluate the safety and effectiveness of the TearCare® System in adult patients with clinically significant dry eye disease (DED).

PATIENTS AND METHODS

This was a prospective, single-center, randomized, parallel-group, clinical trial. Subjects with DED were randomized to either a single TearCare treatment conducted at the clinic or 4 weeks of daily warm compress (WC) therapy. The TearCare procedure consisted of 12 minutes of thermal eyelid treatment immediately followed by manual expression of the meibomian glands. WC therapy consisted of once daily application of the compresses to the eyelids for 5 minutes. Subjects were followed until 6 months post-treatment. The primary effectiveness end point was defined as change from baseline to 4 weeks for tear breakup time (TBUT). Secondary effectiveness end points included meibomian gland assessment, corneal and conjunctival staining scores, and assessment of dry eye symptoms using validated questionnaires. Safety was evaluated by collecting device-related adverse events, intraocular pressure, and best spectacle-corrected Snellen Visual acuity.

RESULTS

Twenty-four subjects were enrolled and all subjects completed 6 months follow-up. At the 1-month follow-up, TearCare subjects demonstrated an improvement from baseline in mean (±SD) TBUT of 11.7±2.6 seconds compared with an average worsening of -0.3±1.1 seconds for subjects in the WC group (p<0.0001). Significantly greater improvements in the change from baseline in meibomian gland scores, as well as corneal and conjunctival staining scores, were observed in the TearCare group. Subjects in the TearCare group also showed significantly greater improvement in dry eye symptoms as measured by the 3 questionnaires. Both treatments were well-tolerated.

CONCLUSION

The findings of this pilot study suggest that the TearCare System is an effective treatment option for patients with DED, with the effects on the signs and symptoms of DED persisting for at least 6 months.

Association between meibomian gland dysfunction and compliance of topical prostaglandin analogs in patients with normal tension glaucoma

PURPOSE

The aim of this study was to investigate the association between tear film and meibomian gland parameters in patients with normal tension glaucoma (NTG), who underwent topical prostaglandin analog (PGA) monotherapy, and medication compliance.

METHODS

Ocular surface disease index (OSDI), Schirmer's test, tear film break-up time (TBUT), keratoepitheliopathy (KEP) score with fluorescein, and meibomian gland parameters were assessed in 45 eyes of 45 patients with NTG (NTG group), who received topical PGA monotherapy for more than 1 year. The results were compared to those of 40 eyes of 40 normal subjects (control group). Medication compliance was assessed by an 8-item Morisky Medication Adherence Scale (MMAS-8). Multiple logistic regression analysis was used to identify the factors associated with medication compliance.

RESULTS

There was a significant difference in OSDI (P = 0.043), Schirmer's test (P < 0.001), TBUT (P < 0.001), KEP score (P = 0.015) and all meibomian gland parameters (all P < 0.001) between two groups. When the NTG group was divided into compliant and non-compliant groups based on the scores of MMAS-8, 30 (75%) patients were classified into the compliant group. Multiple logistic regression analysis revealed that the lid margin score (OR, 0.256; 95% CI, 0.072-0.908, P = 0.035), meibum score (OR, 0.144; 95% CI, 0.023-0.915, P = 0.04), and meibo score (OR, 0.344; 95% CI, 0.140-0.845, P = 0.02) were significant factors associated with compliance in patients with NTG. The meibomian gland parameters showed a negative correlation with medication compliance (all P < 0.005).

CONCLUSIONS

Malfunction of the meibomian glands can be an important clinical finding associated with compliance of PGA monotherapy in patients with NTG.

Meibomian Gland Disease: The Role of Gland Dysfunction in Dry Eye Disease

TOPIC

To discuss the pathology, causes, and ocular surface impact of meibomian gland disease (MGD), as well as its relationship to dry eye.

CLINICAL RELEVANCE

MGD is a common disorder with various contributing mechanisms and clinical manifestations. Understanding MGD pathophysiology and its relationship to dry eye is important in order to optimize diagnosis and treatment algorithms.

METHODS

A review of current literature was performed to discern MGD in terms of pathophysiology, risk factors, and ocular surface impact, and the relationship to dry eye.

RESULTS

Meibomian gland obstruction and meibocyte depletion are important components of MGD. Many pathologies can disrupt function of meibomian glands, ranging from congenital to acquired causes. Once gland disruption occurs, the quality and quantity of meibum is altered, with a negative impact on the ocular surface. Increased tear evaporation, tear hyperosmolarity, increased ocular surface staining, increased inflammation, symptomatic irritation of the eyelid and globes, as well as decreased visual acuity have all been observed.

CONCLUSION

MGD leads to changes in meibum quality and quantity that can cause evaporative dry eye and ocular surface disruption, leading to dry eye symptoms in some individuals.

Morphological evaluation for diagnosis of dry eye related to meibomian gland dysfunction

The evaluation of morphological changes of the acini in the meibomian glands is important for the diagnosis and management of dry eye related to meibomian gland dysfunction. While several tools have been developed to detect meibomian gland structure, infrared imaging is generally used in clinical settings. Unlike the lipid component analysis of tear film in which quantitative analysis is possible, the meibomian glands are limited to qualitative analysis because of the low image quality of the diagnostic tools. This review describes diagnostic tools, especially in terms of morphological evaluation of the acini, which are visualized by the existence of lipid within them.

Effect of Sleep Position on the Ocular Surface

PURPOSE

Dry eye disease is a multifactorial disease with numerous well-documented risk factors. However, to date, sleep position has not been associated with this condition. After observing patients in our practice, we believe that the sleep position in some cases may significantly affect dry eye and meibomian gland dysfunction (MGD).

METHODS

This is a single-centered, cross-sectional, noninterventional, institutional review board-approved, single-masked, nonrandomized study of 100 patients whose complaints were related to dry eye disease and a control group of 25 age-matched asymptomatic patients. Two questionnaires were used: one to analyze patients' sleep habits and the other to assess patients' Ocular Surface Disease Index. Dry eye severity was graded based on the MGD stage, fluorescein corneal staining and lissamine green staining, Schirmer 1 testing, tear osmolarity levels, and clinical examination.

RESULTS

A statistically significant difference was shown with back sleeping compared with left side sleeping using lissamine green staining (analysis of variance, P = 0.005). The Ocular Surface Disease Index score was also found to be elevated in patients who slept on their right or left side (36.4 and 34.1, respectively) as opposed to back sleepers (26.7) with P < 0.05. There was no statistically significant correlation found between the sleep position and degree of MGD.

CONCLUSIONS

In addition to current treatment, patients who sleep on their side or face down might see a reduction in dry eye and MGD if they change their sleep pattern to the supine position.

Relation of accommodative microfluctuation with dry eye symptoms in short tear break-up time dry eye

Purpose

To investigate accommodative microfluctuations (AMFs) and visual function in short tear break-up time (BUT)-type dry eye (DE) and non-DE subjects.

Methods

This prospective comparative study included 48 volunteers with DE symptoms (mean age 34.8 ± 5.5 years, age range 25–42 years) and 73 without DE symptoms (mean age 30.6 ± 4.7 years, age range 25–42 years). The eyes were divided into two groups: (1) DE group with DE symptoms and BUT ≤ 5 s and (2) non-DE group without DE symptoms and BUT > 5 s. We excluded eyes with Schirmer score ≤ 5 mm and positive keratoconjunctival epithelial damage. Tear evaluation, AMF, and functional visual acuity (VA) examinations were performed. AMF parameters included total high-frequency component (HFC), HFC with low accommodation for the task of staring into the distance (HFC1), and HFC with high accommodation for deskwork (HFC2). Functional VA parameters included starting VA, functional VA, visual maintenance ratio, and blink frequency.

Results

A total of 33 and 34 eyes were categorized in the DE and non-DE groups, respectively. Mean blink frequency and HFC1 values were significantly higher in the DE group than they were in the non-DE group.

Conclusions

DEs with symptoms showed abnormal AMF and visual function, which may be associated with DE symptoms.

Vitamin D Replacement Improves Tear Osmolarity in Patients with Vitamin D Deficiency

BACKGROUND

Vitamin D deficiency is a common health problem worldwide. Many parts of the human eye, including the epithelium of the cornea, lens, ciliary body, and retinal pigment epithelium, as well as the corneal endothelium, ganglion cell layer, and retinal photoreceptors, contain vitamin D receptor (VDR). Dry eye is also a common health problem. An adequate tear film is required for maintaining health and function of the eye. Tear hyperosmolarity is considered to be the cause of ocular surface inflammation, symptoms, and tissue damage. It is well-documented that vitamin D has an anti-inflammatory action. We aimed to investigate the effect of vitamin D replacement on tear osmolarity in patients with vitamin D deficiency.

METHODS

A total of 44 patients (38 females, six males, mean age:43.5 ± 12.8 years) with vitamin D deficiency currently managed by the Endocrinology and Metabolism Department of Diskapi Training and Research Hospital in Turkey were enrolled in the study. Patients were given 50,000 units of 25(OH)D₃ intramuscularly, once weekly, over a period of eight weeks. All of the patients underwent tear function osmolarity (TFO) measurement initially and eight weeks after vitamin D replacement. Demographic, anthropometric, and biochemistry data of patients were recorded.

RESULTS

The mean TFO was significantly decreased (313.7 ± 17.3 mOsm/L; 302.7 ± 14.2 mOsm/L, p<0.001) at the end of the second month; 25(OH)D₃ concentrations increased from 8.3 ± 3.5 ng/mL to 68.8 ± 22.3 ng/mL (p<0.001). The mean levels of hsCRP, FPG, P were 2.5 ± 2.5 mg/L, 5.09 ± 0.48 mmol/L, 1.06 ± 0.16 mmol/L initially, and 3.8 ± 5.9 mg/L, 5.11 ± 0.68 mg/dL, 1.09 ± 0.16 mmol/L after vitamin D replacement, respectively (p>0.05). The mean Ca level was 2.37 ± 0.07 mmol/L initially and 2.35 ± 0.07 mmol/L after vitamin D replacement (p<0.05). The change of TFO was negatively correlated with the variation of 25(OH)D₃ before and after replacement in patients with dry eye disease (r=-0.390, p=0.049).

CONCLUSIONS

As a consequence of the presence of VDR and 1α-hydroxylase in different parts of the eye, vitamin D replacement improves tear hyperosmolarity that is considered to be induced by ocular surface inflammation.

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

Fibroblast Growth Factor Receptor 2 (FGFR2) Is Required for Meibomian Gland Homeostasis in the Adult Mouse

Purpose

Little is known about the signaling mechanisms controlling meibomian gland (MG) homeostasis and the pathogenic processes leading to MG atrophy and dysfunction in dry eye disease (DED). We investigated the role of fibroblast growth factor receptor 2 (FGFR2) in the MG homeostasis of adult mice.

Methods

A triple transgenic mouse strain (Krt14-rtTA; tetO-Cre; Fgfr2flox/flox), referred to as Fgfr2CKO mice, was generated in which the Fgfr2 gene is ablated by Cre recombinase in keratin 14 (Krt14)-expressing epithelial cells on doxycycline (Dox) induction. FGFR2 expression in normal human and mouse MGs was evaluated by immunohistochemistry. Pathologic MG changes in transgenic mice with conditional deletion of FGFR2 were examined by lipid staining, histology, and immunostaining.

Results

FGFR2 was highly expressed in normal human MGs and adult mouse MGs. Two-month-old Fgfr2CKO mice fed Dox-containing chow for 2 weeks developed severe MG atrophy. MG acinar atrophy in the Fgfr2CKO mice was associated with reduced lipid (meibum) production and the development of clinical findings similar to those in humans with evaporative DED related to MG dysfunction (MGD). Immunohistochemical analyses showed that FGFR2 deletion severely affected proliferation and differentiation of MG acinar cells but affected MG ductal cells to a lesser extent.

Conclusions

FGFR2 deletion results in significant MG acinar atrophy and clinical manifestations of MGD in Fgfr2CKO mice, suggesting that MG homeostasis is FGFR2 dependent. The Fgfr2CKO mice with inducible MG atrophy can serve as a valuable animal model for investigating the pathogenesis of MGD and developing novel therapeutic strategies for MGD-related DED.

Asymptomatic Meibomian Gland Dysfunction and Cardiovascular Disease Risk Factors in a Middle-Aged Population in Taiwan - A Cross-sectional Analysis

Managing cardiovascular disease (CVD) risk factors is the key to prevent CVD. This study aimed to prevent CVD by introducing asymptomatic meibomian gland dysfunction (MGD), a condition associated with various CVD risk factors, as an early indicator for CVD in middle-aged population. Participants with and without asymptomatic MGD underwent standardized questionnaires, physical examinations, and laboratory investigations. One ophthalmologist completed the identification and grading of MGD by using slit-lamp biomicroscopy examination on the eyelid margins, meibomian gland orifices, and meibomian gland secretions. Standardized techniques were used to measure the CVD risk factor parameters. After adjusted for age and gender, CVD risk factors including elevated uric acid (P = 0.01), total cholesterol (Total-C, P < 0.001), low-density lipoprotein cholesterol (LDL-C, P < 0.001), fasting triglyceride (Fasting TG, P < 0.001), decreased high-density lipoprotein cholesterol (HDL-C, P = 0.04), and presence of hepatic steatosis (P = 0.008) were significantly associated with asymptomatic MGD. Stepwise logistic regression analysis revealed that LDL-C (OR: 1.03, 95% CI: 1.02–1.04) and Fasting TG (OR: 1.01; 95% CI: 1.00–1.01) levels were risk factors for having asymptomatic MGD (P < 0.001). Together, the results suggest that asymptomatic MGD may serve as an indicator for CVD.

Dry Eye Management: Targeting the Ocular Surface Microenvironment

Dry eye can damage the ocular surface and result in mild corneal epithelial defect to blinding corneal pannus formation and squamous metaplasia. Significant progress in the treatment of dry eye has been made in the last two decades; progressing from lubricating and hydrating the ocular surface with artificial tear to stimulating tear secretion; anti-inflammation and immune regulation. With the increase in knowledge regarding the pathophysiology of dry eye, we propose in this review the concept of ocular surface microenvironment. Various components of the microenvironment contribute to the homeostasis of ocular surface. Compromise in one or more components can result in homeostasis disruption of ocular surface leading to dry eye disease. Complete evaluation of the microenvironment component changes in dry eye patients will not only lead to appropriate diagnosis, but also guide in timely and effective clinical management. Successful treatment of dry eye should be aimed to restore the homeostasis of the ocular surface microenvironment.

Ectodysplasin A protein promotes corneal epithelial cell proliferation

The EDA gene encodes ectodysplasin A (Eda), which if mutated causes X-linked hypohidrotic ectodermal dysplasia (XLHED) disease in humans. Ocular surface changes occur in XLHED patients whereas its underlying mechanism remains elusive. In this study, we found Eda was highly expressed in meibomian glands, and it was detected in human tears but not serum. Corneal epithelial integrity was defective and the thickness was reduced in the early postnatal stage of Eda mutant Tabby mice. Corneal epithelial cell proliferation decreased and the epithelial wound healing was delayed in Tabby mice, whereas it was restored by exogenous Eda. Eda exposure promoted mouse corneal epithelial wound healing during organ culture, whereas scratch wound assay showed that it did not affect human corneal epithelial cell line migration. Epidermal growth factor receptor (EGFR), phosphorylated EGFR (p-EGFR), and phosphorylated ERK1/2 (p-ERK) were down-regulated in Tabby mice corneal epithelium. Eda treatment up-regulated the expression of Ki67, EGFR, p-EGFR, and p-ERK in human corneal epithelial cells in a dose-dependent manner. In conclusion, Eda protein can be secreted from meibomian glands and promotes corneal epithelial cell proliferation through regulation of the EGFR signaling pathway. Eda release into the tears plays an essential role in the maintenance of corneal epithelial homeostasis.

Growth of meibomian gland tissue after intraductal meibomian gland probing in patients with obstructive meibomian gland dysfunction

PURPOSE

To investigate the impact of meibomian gland probing (MGP) on meibomian gland (MG) area from the upper lids of patients with obstructive meibomian gland dysfunction (o-MGD).

METHODS

Retrospective study comparing pre-MGP/post-MGP non-contact infrared meibography results in patients with o-MGD, viewing signs of MG growth within total measurement field.

RESULTS

Post-MGP meibography of 34 lids (19 patients, ≥4.5 to ≤12 months' follow-up) showed 41.2% with MG growth. Ten lids had meibographies suitable for analysis, showing significant collective (116 glands) increase in mean individual glandular area (MIGA) of 4.87% (p=0.0145). Four of 10 lids independently showed significant increase in MIGA, ranging from 10.70% to 21.13% (p<0.0001, p=0.0277, p=0.0292, p=0.0345), while six did not.At >12 and <25 months' follow-up, 16 lids (9 additional patients) had follow-up showing 25% with signs of MG growth. Analysis of three lids showed a significant collective (33 glands) increase in MIGA of 11.19% (p=0.0004). Two of three lids independently showed significant increase in MIGA of 13.73% and 20.00% (p=0.0097, p=0.0001). Collectively, for all 13 analysed lids (149 glands), there was a significant increase of 6.38% in total glandular area (p=0.0447) and a significant increase of 6.23% in MIGA (p=0.0003).

CONCLUSION

MGP was associated with increased MG tissue area and growth of atrophied MGs as viewed on meibography. MGP provides unequivocal physical proof of a patent meibum outflow tract through the natural orifice, and may promote glandular growth in part by direct mechanical establishment of a patent duct/orifice system.

RETRACTED: Azithromycin 1.5% Ophthalmic Solution for Blepharitis Treatment: Comparison of 14- Versus 30-Day Treatment

The online-ahead-of-print published article, "Azithromycin 1.5% Ophthalmic Solution for Blepharitis Treatment: Comparison of 14- Versus 30-Day Treatment," by Altay Yesim, Demirok Gulizar, Balta Ozgur, and Bolu Hulya (DOI: 10.1089/jop.2015.0099) is being officially retracted from Journal of Ocular Pharmacology and Therapeutics (JOPT) due to post-publication authorship disputes and the discovery of simultaneous submission to both JOPT and the International Journal of Ophthalmology, which is a violation of the proper protocols of peer review. Journal of Ocular Pharmacology and Therapeutics and its editorial leadership are committed to maintaining the highest levels of scientific reporting and publishing, and therefore officially retracts the article based on the infringements listed herein.

Meibography for eyes with posterior blepharitis

Purpose

To study the effect of posterior blepharitis on meibomian glands using infrared meibography and to correlate the results with tear film parameters.

Methods

This is a prospective cohort study. The study included eyes from two groups: 86 eyes of healthy volunteers’ eyes and 72 eyes with posterior blepharitis. Participants were examined, and diagnosis of posterior blepharitis was achieved clinically based on signs of posterior blepharitis. Clinical assessment of dryness was performed including slit lamp examination looking for signs of posterior blepharitis, tear breakup time (TBUT), superficial punctate keratopathy (SPK), Schirmer II test (with anesthesia) and meibum score. Non-contact meibography was performed for both upper and lower eyelids using the meibo-grade system which involved distortion of meibomian gland, shortening and dropout.

Results

Lid margin abnormalities (Telangiectasia, lid margin swelling and hyperemia) were all significantly higher in the posterior blepharitis group. SPK, meibum score, meibography dropout, distortion, shortening, and total meibography were all significantly higher in the posterior blepharitis group as well as meibum score (P value < 0.001). TBUT was significantly shorter in the posterior blepharitis group (P value < 0.001). There was no significant difference between the two groups in Schirmer’s II test.

Conclusion

Meibography can be a helpful non-invasive tool for the clinical evaluation of the extent of the anatomical damage in patients having meibomian glands loss due to posterior blepharitis. Knowing the extent of damage in meibomian glands may help in selecting the appropriate treatment modality and expect the response to treatment in patients with posterior blepharitis.

Manifestation of meibomian gland dysfunction in patients with Sjögren's syndrome, non-Sjögren's dry eye, and non-dry eye controls

PURPOSE

To evaluate the manifestation of meibomian gland dysfunction in patients with Sjögren's syndrome (SS), non-Sjögren's syndrome dry eye (non-SS) patients, and non-dry eye controls.

METHODS

We recruited 31 participants with SS dry eye, 30 participants with non-SS dry eye, and 35 healthy controls without dry eye symptoms. Noninvasive tear breakup time (NITBUT) and meibomian gland dropout score (meiboscore) were measured using the Oculus Keratograph 5 M. Meibomian gland expressibility and secretion quality were evaluated via slit lamp biomicroscopy. The correlation between measurements was analyzed.

RESULTS

NITBUT was lower, and the meiboscore, meibomian gland expressibility, and secretion quality scores were significantly higher in the SS and non-SS groups than in the control group (p < 0.001). NITBUT was lower, and the meiboscore and meibomian gland expressibility were higher in the SS group than in the non-SS group. NITBUT correlated negatively with the meiboscore in both SS and non-SS groups and with meibomian gland expressibility in the SS group. A positive correlation was obtained between meiboscore and meibomian gland expressibility in both the SS and the non-SS groups.

CONCLUSION

Patients in both SS and non-SS groups exhibited greater impairment in meibomian gland function than the non-dry eye controls. SS patients had more severe meibomian gland dysfunction with poorer mean meiboscore and meibomian gland expressibility than non-SS patients.

Increase in tear film lipid layer thickness after instillation of 3% diquafosol ophthalmic solution in healthy human eyes

PURPOSE

To evaluate the effect of 3% diquafosol ophthalmic solution on tear film lipid layer thickness (LLT) in normal human eyes by tear interferometry.

METHODS

Forty-seven healthy men (mean age of 42.4 years) randomly received one drop of artificial tears in one eye and one drop of 3% diquafosol ophthalmic solution in the other. LLT of each eye was quantified by tear interferometry before and 15, 30, and 60 min after instillation. Ocular symptoms were assessed before and 30 min after instillation. Baseline LLT, tear film breakup time (TBUT), meibomian gland area (meiboscore) of the upper and lower eyelids, and Schirmer test value were evaluated on a different day before treatment.

RESULTS

LLT before and 15, 30, and 60 min after diquafosol instillation was 62.3 ± 31.1, 77.0 ± 39.5, 79.3 ± 40.5, and 77.7 ± 43.6 nm, respectively, with the diquafosol-induced increase in LLT being significant at each time point. Artificial tears did not result in a significant increase in LLT. TBUT (ρ = 0.32, P = 0.026), meiboscore of the lower eyelid (ρ = -0.33, P = 0.022), and the maximum difference in LLT between before and after diquafosol instillation (ΔLLT_max) (ρ = 0.35, P = 0.016) were significantly correlated with baseline LLT in the diquafosol group. Age was not significantly related to baseline LLT or ΔLLT_max. Symptoms did not differ significantly between the two groups.

CONCLUSIONS

Topical instillation of 3% diquafosol ophthalmic solution increased LLT for up to 60 min in normal human eyes regardless of age.

Corneal thickness in dry eyes in an Iraqi population

BACKGROUND

Dry eye disorder is a multifactorial disease of the tears and ocular surface that results in discomfort and visual disturbance. Corneal pachymetry becomes increasingly important in refractive surgery, for the accurate assessment of intraocular pressure, and in the preoperative assessment of other ocular surgeries.

PURPOSE

To assess the effect of dry eye disorder on the central corneal thickness (CCT) by comparing with CCT of normal eyes of age-matched individuals.

PATIENTS AND METHODS

The total number of eyes examined was 280 (140 dry eyes from 70 patients and 140 normal eyes from 70 individuals). Pentacam (Scheimpflug imaging system) was used for measuring the CCT of all eyes.

RESULTS

Patients with dry eye syndrome had significantly lower CCT compared to the control group (P<0.01). Its mean was 536.5 versus 561.3, respectively.

CONCLUSION

CCT of dry eyes was significantly reduced when compared with age- and gender-matched population. This result can be attributed to chronic desiccation by the inflammatory mediators in dry eyes, leading to corneal thinning.

Emerging strategies for the diagnosis and treatment of meibomian gland dysfunction: Proceedings of the OCEAN group meeting

Meibomian gland dysfunction (MGD) is a common and chronic disorder that has a significant adverse impact on patients' quality of life. It is a leading cause of evaporative dry eye disease (DED), as meibomian glands play an important role in providing lipids to the tear film, which helps to retard the evaporation of tears from the ocular surface. MGD is also often present in conjunction with primary aqueous-deficient DED. Obstructive MGD, the most commonly observed type of MGD, is the main focus of this article. MGD is probably caused by a combination of separate conditions: primary obstructive hyperkeratinization of the meibomian gland, abnormal meibomian gland secretion, eyelid inflammation, corneal inflammation and damage, microbiological changes, and DED. Furthermore, skin diseases such as rosacea may play a part in its pathology. Accurate diagnosis is challenging, as it is difficult to differentiate between ocular surface diseases, but is crucial when choosing treatment options. Ocular imaging has advanced in recent years, providing ophthalmologists with a better understanding of ocular diseases. This review presents a literature update on the 2011 MGD workshop and an optimized approach to accurate diagnosis of MGD using currently available methods and tests. It also outlines the emerging technologies of interferometry, non-contact meibography, keratography and in vivo confocal laser microscopy, which offer exciting possibilities for the future. Selected treatment options for MGD are also discussed.

Risk Factors and Symptoms of Meibomian Gland Loss in a Healthy Population

Purpose. The aim of this study was to investigate the relationships between MGL and ocular symptoms, several systemic conditions, and key markers of ocular surface health. Methods. We included into the study 91 healthy volunteers between the ages of 20 and 77 years. We analyzed meibomian gland morphology, function, and lid margin alterations. We correlated our findings with self-reported ocular symptoms, systemic medical history, lifestyle factors, and tear film abnormalities. Results. We observed that a high ocular surface disease index, a history of either chalazion or hordeolum, experience of puffy eyelids upon waking, and foreign body sensation all appeared to be predictors of an abnormal meiboscore after adjusting for age and sex (p = 0.0007; p = 0.001; p = 0.02; p = 0.001, resp.). Multivariate logistic regression model including age and sex showed that there were three independent predictors of abnormal meiboscore: older age (OR = 1.03, 95% CI = 1.01–1.04 per year, p = 0.006), postmenopausal hormone therapy (OR = 4.98, 95% CI = 1.52–16.30, p = 0.007), and the use of antiallergy drugs (OR = 5.85, 95% CI = 2.18–15.72, p = 0.0004). Conclusion. Our findings extend current knowledge on the pathophysiology of MGL.

iDEAS: A web-based system for dry eye assessment

BACKGROUND AND OBJECTIVES

Dry eye disease is a public health problem, whose multifactorial etiology challenges clinicians and researchers making necessary the collaboration between different experts and centers. The evaluation of the interference patterns observed in the tear film lipid layer is a common clinical test used for dry eye diagnosis. However, it is a time-consuming task with a high degree of intra- as well as inter-observer variability, which makes the use of a computer-based analysis system highly desirable. This work introduces iDEAS (Dry Eye Assessment System), a web-based application to support dry eye diagnosis.

METHODS

iDEAS provides a framework for eye care experts to collaboratively work using image-based services in a distributed environment. It is composed of three main components: the web client for user interaction, the web application server for request processing, and the service module for image analysis. Specifically, this manuscript presents two automatic services: tear film classification, which classifies an image into one interference pattern; and tear film map, which illustrates the distribution of the patterns over the entire tear film.

RESULTS

iDEAS has been evaluated by specialists from different institutions to test its performance. Both services have been evaluated in terms of a set of performance metrics using the annotations of different experts. Note that the processing time of both services has been also measured for efficiency purposes.

CONCLUSIONS

iDEAS is a web-based application which provides a fast, reliable environment for dry eye assessment. The system allows practitioners to share images, clinical information and automatic assessments between remote computers. Additionally, it save time for experts, diminish the inter-expert variability and can be used in both clinical and research settings.

Mechanisms and management of dry eye in cataract surgery patients

PURPOSE OF REVIEW

To provide a summary of the mechanisms that may cause dry eye after cataract surgery and discuss available and upcoming treatment modalities.

RECENT FINDINGS

Development or worsening of dry eye symptoms after cataract surgery is multifactorial with corneal nerve transection, inflammation, goblet cell loss, and meibomian gland dysfunction commonly cited as underlying disorders. With increasing awareness of the prevalence of dry eye disease, current surgical techniques are being analyzed for their contribution to the issue. Although many classic interventions, such as artificial tears and anti-inflammatory drops, remain first-line treatment options, they may not adequately address abnormalities of the tear film. The trend has been to create new drugs and technologies that target meibomian gland deficiencies and restore goblet cell numbers.

SUMMARY

Therapy for postoperative dry eye symptoms should be determined based on symptom severity and which underlying cause is most prominent at a given time. Patients with high-level risk factors for dry eye should be evaluated preoperatively to determine whether they have preexisting dry eye disease or if they are susceptible to developing disease after surgery.

Meibomian gland dysfunction in Graves' orbitopathy

OBJECTIVE

To examine morphologic changes in the meibomian glands associated with patients with Graves' orbitopathy (GO) using a novel meibography imaging system, and to evaluate its correlation with GO clinical manifestations.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Fifty-one GO patients and 31 normal control participants.

METHODS

This retrospective study examined 51 GO patients and 31 normal control participants. The structure of the meibomian gland was assessed using the meibography imaging system. All of the participants completed the Ocular Surface Disease Index (OSDI) questionnaire. The tear film break-up time (BUT) was measured. The palpebral fissure height, exophthalmos, and eyelid retraction were also assessed.

RESULTS

The meibography score, tear film BUT, and OSDI indicated statistically significant differences between the GO and normal groups: The tear film BUT was shorter and the OSDI and meibography score were higher in the GO patient group. There was a significant negative correlation between the meibography score and the tear film BUT in GO patients (r = -.503 and p < .001). In the multivariable linear regression analysis, the meibography score of the GO patients had a positive association with exophthalmos and palpebral fissure height.

CONCLUSIONS

Compared with the normal control participants, GO patients had more unstable tear films and severe symptoms of dry eye. Using the meibography system, the authors found that GO patients had a higher prevalence of obstructive type meibomian gland dysfunction and changes in meibomian glands increased, with proptosis and lid fissure widening.

Review: The Lacrimal Gland and Its Role in Dry Eye

The human tear film is a 3-layered coating of the surface of the eye and a loss, or reduction, in any layer of this film may result in a syndrome of blurry vision and burning pain of the eyes known as dry eye. The lacrimal gland and accessory glands provide multiple components to the tear film, most notably the aqueous. Dysfunction of these glands results in the loss of aqueous and other products required in ocular surface maintenance and health resulting in dry eye and the potential for significant surface pathology. In this paper, we have reviewed products of the lacrimal gland, diseases known to affect the gland, and historical and emerging dry eye therapies targeting lacrimal gland dysfunction.

Prevalence and associated factors of dry eye: Our experience in patients above 40 years of age at a Tertiary Care Center

Context:

Dry eye is a very common as well as under-diagnosed ocular disorder. It is not only troublesome in terms of its symptoms but also imposes a great financial burden.

Aims:

To determine the prevalence of dry eye in ophthalmology out-patients at a Tertiary Care Hospital and its association with various clinico-epidemiological factors.

Settings and Design:

A hospital-based study at a Tertiary Care Center was conducted including 400 out-patients of age 40 years and above.

Materials and Methods:

Patients were consecutively selected and underwent a routine ophthalmological examination along with tear film break-up time (TBUT) as a screening tool for detecting the presence of dry eye.

Statistical Analysis:

We performed a descriptive, univariate and multivariable logistic regression analysis to calculate odds ratios and 95% confidence interval.

Results:

The mean age of the study population was 58.6 years. The overall prevalence of dry eye was found to be 54.3%. An association was found between dry eye prevalence and outdoor workers, participants working indoor using air conditioners, housewives, diabetics, patients who have undergone previous ocular surgery and those with meibomian gland dysfunction.

Conclusions:

Dry eye is a very common condition with a high prevalence among the elderly. We recommend the screening of all out-patients by TBUT, which is a simple test to perform and examination of lids for meibomian gland disease, which if present can be treated. Further studies are needed to establish uniform diagnostic criteria for dry eye, which will help to get more concrete prevalence data, as well as its etiological factors.

Ocular Surface Cooling Corresponds to Tear Film Thinning and Breakup

PURPOSE

To investigate the relationship between ocular surface temperature (OST) and tear film thinning and breakup.

METHODS

Simultaneous imaging of OST and fluorescein tear thinning and breakup (FTBU) was performed on 20 subjects. Subjects were asked to open their eyes and refrain from blinking for as long as they could during testing. Ocular surface temperature was measured using an infrared thermographic camera (FLIR A655sc) and rates of ocular surface cooling (OSC) were analyzed using commercially available software. A method was developed to quantify the rate of FTBU formation using image-processing software.

RESULTS

Areas of FTBU and regions of OSC were observed to be colocalized, with localized cooling preceding the formation of FTBU. The rates of OSC and FTBU formation were positively correlated (r = 0.74). A second-order polynomial model accurately describes the physiological relationship between the area of FTBU and OST (p < 0.001). A linear approximation provides a more clinically interpretable rate of FTBU formation with decreasing OST (p < 0.001), while still retaining high R.

CONCLUSIONS

The results suggest a direct relationship between FTBU formation and OSC. That cooling of the ocular surface precedes FTBU formation implies a process of evaporation contributing to tear film thinning and breakup. Our study suggests that measuring the OSC rate could be an indirect assessment of tear evaporation and could contribute to the management of evaporative dry eye.