Is complete androgen insensitivity syndrome associated with alterations in the meibomian gland and ocular surface?

Inflammation in Dry Eye Disease-Pathogenesis, Preclinical Animal Models, and Treatments

Dry eye disease (DED) is a rapidly growing ocular surface disease with a significant socioeconomic impact that affects the patients' visual function and, thus, their quality of life. It is distinguished by a loss of tear film homeostasis, leading to tear film instability, hyperosmolarity, ocular surface inflammation, and neurosensory abnormalities, with all of these playing etiological roles in the propagation of the vicious DED circle. While current treatments primarily focus on reducing tear film instability and hyperosmolarity, increasingly more attention is being placed on tackling the underlying inflammation that propagates and potentiates these factors. As such, preclinical models are crucial to further elucidate the DED pathophysiology and develop novel therapeutic strategies. This review outlines the role of inflammation in DED, highlighting related signs and diagnostic tools before focusing on relevant preclinical animal models and potential therapeutic strategies to tackle DED-associated inflammation.

The relationship between sex hormone levels and ocular surface parameters in girls with idiopathic central precocious puberty

Purpose

The study aimed to investigate the correlation between the change of sex hormone levels and ocular surface parameters in girls with idiopathic central precocious puberty(ICPP).

Methods

Eighteen girls with ICPP and 18 age-matched normal girls participated in this study, all of the participants had undergone physical measurements, laboratory tests, imaging examination and ocular surface assessments.

Results

The Objective Scatter Index (OSI) in the ICPP group was significantly higher than in the control group (P = 0.031), girls with ICPP showed slightly lower MNITBUT compared to the normal control group, although this difference was not statistically significant. Bivariate analysis revealed a positive association between estradiol and OSI (r=0.383, P=0.021), Additionally, in the study population, both Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH) were negatively correlated with Mean noninvasive tear breakup time (MNITBUT) (r=-0.359, P=0.031)(r=-0.357, P=0.032).

Conclusion

In comparison with the normal control group, alterations in the OSI were observed in girls with ICPP. This alteration may be associated with an elevation in estrogen levels. Although there was a slight non-significant decrease in NITBUT in ICPP girls, the negative correlation between LH and FSH with MNITBUT suggests new perspective for further investigation.

TFOS Lifestyle: Impact of lifestyle challenges on the ocular surface

Many factors in the domains of mental, physical, and social health have been associated with various ocular surface diseases, with most of the focus centered on aspects of dry eye disease (DED). Regarding mental health factors, several cross-sectional studies have noted associations between depression and anxiety, and medications used to treat these disorders, and DED symptoms. Sleep disorders (both involving quality and quantity of sleep) have also been associated with DED symptoms. Under the domain of physical health, several factors have been linked to meibomian gland abnormalities, including obesity and face mask wear. Cross-sectional studies have also linked chronic pain conditions, specifically migraine, chronic pain syndrome and fibromyalgia, to DED, principally focusing on DED symptoms. A systematic review and meta-analysis reviewed available data and concluded that various chronic pain conditions increased the risk of DED (variably defined), with odds ratios ranging from 1.60 to 2.16. However, heterogeneity was noted, highlighting the need for additional studies examining the impact of chronic pain on DED signs and subtype (evaporative versus aqueous deficient). With respect to societal factors, tobacco use has been most closely linked to tear instability, cocaine to decreased corneal sensitivity, and alcohol to tear film disturbances and DED symptoms.

Tear film impairment and meibomian gland loss in patients with polycystic ovary syndrome

OBJECTIVE

The aim of this prospective study is to comparatively assess the tear film, meibomian gland (MG), cornea and anterior chamber parameters and also subjective ocular complaints in patients with polycystic ovary syndrome (PCOS) and healthy control subjects.

MATERIALS AND METHODS

We included 53 eyes of the 53 patients diagnosed with PCOS and 57 eyes of the 57 healthy control subjects (who are non-pregnant, none of the following clinical findings of male pattern hair loss, hirsutism or acne and with regular menstrual cycles, who have no laboratory findings in her medical history that indicate hyperandrogenism, and who have ovaries that appear to be normal ultrasonographically. All subjects were referred to the masked ophthalmologist by the obstetrician and gynecologist. Participants underwent evaluation of the non-invasive tear film break-up time test (NI-BUT); loss of MGs by non-contact meibography, evaluation of cornea and anterior chamber parameters, and evaluation of subjective ocular complaints using the ocular surface disease index (OSDI).

RESULTS

The mean age of PCOS group and controls was 25.08 ± 4.88 and 25.44 ± 5.00 years, respectively. There was no statistically significant difference between the PCOS and control groups in terms of age (p = 0.732). Mean non-invasive first tear film breakup times (NIF-BUT) values of PCOS group and controls were 6.15 ± 4.99 and 10.48 ± 5.81 s, and mean non-invasive average tear film breakup times (NIAvg-BUT) values of PCOS group and controls were 8.48 ± 4.27 and 11.94 ± 4.64 s, respectively; both cases refer to a significant difference between the groups (p = 0.000). In PCOS group, loss of MG in the upper lids was 40.21%, in the lower lids was 53.45%; on the other hand, in control group 15.76% and 21.47%, respectively; both cases refer to a significant difference between the groups (p = 0.000). The number of patients with abnormal OSDI scores (scores ≥ 13 points) was significantly higher in PCOS group (54.7%) than in controls (19.3%) (p = 0.000). Anterior chamber volume (ACV) measured by the topography device in PCOS group was significantly lower (156.5 and 167.4) (p = 0.024).

CONCLUSION

Findings of this study indicated that tear film stability impaired in patients with PCOS and that this impairment was accompanied by the loss of MG, which play a key role in tear film stability.

The morphogenesis of the rabbit meibomian gland in relation to sex hormones: Immunohistochemical and transmission electron microscopy studies

Rabbits have been proposed as a model for the human meibomian gland (MG), a large specific sebaceous gland in the eyelid that consists of secretory acini arranged laterally and related to the central duct via short ductules, with the central duct continuing as an excretory duct to open at the free margin of the lid. First detected at embryonic day 18 as an aggregation of mesenchymal cells in the tarsal plate, it completes its development approximately 2 weeks postnatal when the separation of the eyelids is completed. The Transmission electron microscopy supports the meibocytes’ gradient maturation to the meibum’s synthesis. While the differentiating cells, their cytoplasm, are well packed with lipid droplets, the basal cells are characterized by a high nuclear to cytoplasm ratio. The androgen and estrogen receptor proteins are expressed in the basal cell and the meibocytes, and increase in age increases in the expression of these proteins. Additionally, the cytokeratin (CK14) is expressed in the basal and differentiating cells of the acini and the ductal epithelium. Therefore, the duct cells of the MG are common in all stem cells. These data concluded that the MG plays a major role in maintaining the health of the ocular surface and preservation of visual acuity. Any abnormalities in the structure of the MG lead to its dysfunction and changes in lipid secretion.

Effects of systemic anti-androgen drugs on the ocular surface

PURPOSE

To investigate the effect of systemic anti-androgen drugs on tear function tests and the ocular surface.

METHODS

Sixty-four male subjects were included in this study. Subjects who were on anti-androgen treatment for prostate cancer (Group A, n: 31) and those who had received only surgical treatment for prostate cancer (Group B, n: 17) were recruited from the department of urology. Age-matched subjects who had never received anti-androgen treatment (Group C, n: 16) constituted the control group. Group A was divided into two subgroups according to the number of anti-androgen drugs used (Group A1: one drug, Group A2: two drugs). All cases underwent a complete ocular examination, including tear film break up time (TBUT), corneal and conjunctival staining, Schirmer 1 test, conjunctival impression cytology, and ocular surface disease index (OSDI) questionnaire.

RESULTS

The mean Schirmer's values were 6.87mm, 11.41mm, and 13.03mm in Groups A, B, and C, respectively (P=0.001). TBUT was 5.45±2.01, 9.85±2.52 and 9.81±1.96seconds in Groups A, B, and C, respectively (P=0.001). Schirmer and TBUT were significantly lower, and corneal staining and OSDI questionnaire scores were higher in Group A compared to groups B and C (P<0.01). Conjunctival impression cytology results according to the Nelson grading system revealed no statistically significant difference between the groups (P=0.422).

CONCLUSION

Anti-androgen drugs alter tear function tests, cause increased corneal and conjunctival staining scores and worsen complaints of dry eye in patients with prostate cancer.

Sex Hormones and Their Effects on Ocular Disorders and Pathophysiology: Current Aspects and Our Experience

Sex hormones are molecules produced by the gonads and to a small extent by the adrenal gland, which not only determine the primary and secondary sexual characteristics of an individual, differentiating man from woman, but also participate in the functioning of the various systems of the body. The evidence that many eye diseases differ in terms of prevalence between men and women has allowed us, in recent years, to carry out several studies that have investigated the association between sex hormones and the pathophysiology of eye tissues. Specific receptors for sex hormones have been found on the lacrimal and meibomian glands, conjunctiva, cornea, lens, retina, and choroid. This work summarizes the current knowledge on the role that sex hormones play in the pathogenesis of the most common ocular disorders and indicates our clinical experience in these situations. The aim is to stimulate an interdisciplinary approach between endocrinology, neurology, molecular biology, and ophthalmology to improve the management of these diseases and to lay the foundations for new therapeutic strategies.

Electronic Device Screen Time and Meibomian Gland Morphology in Children

Purpose

To investigate changes in meibomian gland morphology and impact of electronic device usage time on meibomian glands in pediatric age group.

Methods

In this prospective study, 149 eyes of 149 children were enrolled. The participants also completed the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire and provided information regarding weekly hours spent in front of a digital screen. Meibography was performed in all subjects. Grading of images was evaluated using a previously validated 5-point meiboscale (0–4) for meibomian gland atrophy and a 3-point scale for meibomian gland tortuosity (0–2).

Results

Of the 149 enrolled children, 83 (55.7%) were female and 66 (44.3%) male. The mean age was 13.0 ± 3.0 (range, 5–18) years. The mean loss of meibomian gland area was 20.80 ± 9.32%. The mean meiboscore was 1.20 ± 0.58 for gland atrophy and the mean tortuosity score was 0.99 ± 0.62. The mean screen time was 29.32 ± 16.18 hr/week. There was a weak and significantly positive correlation between loss of meibomian gland area and screen time (r = 0.210, P = 0.010). There was a weak and significantly positive correlation between meiboscore for gland atrophy and screen time (r = 0.188, P = 0.022). We found a weak but significantly positive correlation between meibomian gland tortuosity and screen time (r = 0.142, P = 0.033).

Conclusion

Meibomian gland morphology may show changes in pediatric age group and excessive screen time may be a factor triggering these changes in gland morphology.

Human meibomian gland epithelial cell culture models: Current progress, challenges, and future directions

The widely used immortalised human meibomian gland epithelia cell (iHMGEC) line has made possible extensive studies of the biology and pathophysiology of meibomian glands (MG). Tissue culture protocols for iHMGEC have been revised and modified to optimise the growth conditions for cell differentiation and lipid accumulation. iHMGEC proliferate in serum-free medium but require serum or other appropriate exogenous factors to differentiate. Several supplements can enhance differentiation and neutral lipid accumulation in iHMGEC grown in serum-containing medium. In serum-free medium, rosiglitazone, a peroxisome proliferator activator receptor-γ (PPARγ) agonist, is reported to induce iHMGEC differentiation, neutral lipid accumulation and expression of key biomarkers of differentiation. iHMGEC cultured in serum-containing medium under hypoxia or with azithromycin increases DNAse 2 activity, a biomarker of terminal differentiation in sebocytes. The production of lipids with composition similar to meibum has not been observed in vitro and this remains a major challenge for iHMGEC culture. Innovative methodologies such as 3D ex vivo culture of MG and generation of MG organoids from stem cells are important for further developing a model that more closely mimics the in vivo biology of human MG and to facilitate the next generation of studies of MG disease and dry eye.

The Ocular Surface Characteristics in Prostate Cancer Patients Treated with Androgen Deprivation Therapy

Background

To investigate the association of long-term androgen deprivation therapy (ADT) with ocular surface characteristics in prostate cancer patients.

Methods

A total of 30 male prostate cancer patients who received ADT were selected. All candidates were scored using the Ocular Surface Disease Index (OSDI) and subsequently divided into two groups containing 9 symptomatic patients (scores >12) and 21 asymptomatic patients (scores ≤ 12). Another 20 healthy age-matched males were selected as the control group. Each candidate was assessed with respect to eyelid margin abnormality, tear film break-up time (NI-BUT), tear meniscus height (TMH), meiboscore, meibum expressibility, and demodex infection.

Results

The NI-BUT in the ADT group was significantly shorter than that in the control group. The scores for OSDI, eyelid margin abnormality, meibum expressibility, and meiboscores were significantly higher in the ADT group (P < 0.05). Moreover, the NI-BUT in the symptomatic ADT group was significantly shorter than that in the asymptomatic ADT group (P < 0.05). The meiboscores and meibum expressibility score in the symptomatic ADT group were significantly higher than those in the asymptomatic ADT group (P < 0.05). The presence of demodex in the symptomatic ADT group was also higher than that in the asymptomatic ADT group (P < 0.05).The length of time that patients had been taking ADT was positively correlated with meiboscores and negatively correlated with NI-BUT.

Conclusion

Androgen levels were associated with significant changes in relative meibomian gland function. Subjective symptoms, such as dryness and foreign body sensation, were more obvious in prostate cancer patients receiving ADT, which may be caused by MGD and demodex infection. It's recommended that more attention be paid to the ocular surface in prostate cancer patients taking ADT by performing examination of NI-BUT and meibomian gland morphology and function with a view to providing more comprehensive prevention and treatment protocols.

Sex Hormones Related Ocular Dryness in Breast Cancer Women

Background: Dry eye syndrome (DES) is strictly connected to systemic and topical sex hormones. Breast cancer treatment, the subsequent hormonal therapy, the subsequent hyperandrogenism and the early sudden menopause, may be responsible for ocular surface system failure and its clinical manifestation as dry eye disease. This local dryness is part of the breast cancer iatrogenic dryness, which affects overall mucosal tissue in the fragile population of those with breast cancer. Methods: A literature review regarding the role of sex hormone changes and systemic hormonal replacement treatments (SHRT) in DES available on PubMed and Web of Science was made without any restriction of language. Results: Androgens exert their role on the ocular surface supporting meibomian gland function and exerting a pro-sebaceous effect. Estrogen seems to show a pro/inflammatory role on the ocular surface, while SHRT effects on dry eye are still not well defined, determining apparently contradictory consequences on the ocular surface homeostasis. The role of sex hormones on dry eye pathogenesis is most likely the result of a strict crosstalk between the protective androgens effects and the androgen-modulating effects of estrogens on the meibomian glands. Conclusions: Patients with a pathological or iatrogenic hormonal imbalance, such as in the case of breast cancer, should be assessed for dry eye disease, as well as systemic dryness, in order to restore their social and personal quality of life.

Androgen deprivation therapy and the risk of subsequent keratitis

Objectives:

The objective of the study was to determine the risk of subsequent keratitis in prostate cancer (PCa) patients treated with androgen deprivation therapy (ADT).

Materials and Methods:

Three thousand three hundred and nine patients with PCa were identified using data from Taiwan’s National Health Insurance Research Database for 2001 through 2013. Among those patients, 856 treated with ADT comprised the study group, while 856 non-ADT-treated patients matched with 1:1 propensity-score-matched analysis comprised the control group. The demographic characteristics and comorbidities of all the patients were analyzed, and Cox proportional hazards regression was utilized to determine the hazard ratios (HRs) for subsequent keratitis.

Results:

A total of 157 (9.2%) patients had newly diagnosed keratitis. Compared to the non-ADT-treated patients, the ADT-treated patients had a reduced risk of subsequent keratitis, with an adjusted HR of 0.38 (95% confidence interval: 0.27–0.55; P < 0.001).

Conclusion:

ADT treatment apparently decreased the risk of subsequent keratitis in the investigated PCa patients, but the clinical significance of this finding should be further assessed in additional studies.

The applications of androgen in the treatment of dry eye disease: a systematic review of clinical studies

Androgen regulates the function of lacrimal and meibomian glands, and its deficiency is a pathological factor underlying dry eye disease (DED). However, no androgen has been approved for treating DED due to lack of definite evidence regarding its efficacy and safety in clinics. In this systematic review, we have summarized the clinical studies on the safety and efficacy of androgen replacement therapy (ART) for DED. Medline (via Pubmed), Embase, Clinicaltrials.gov, Wanfang and Chinese Clinical Trials Registry Database were searched for the relevant prospective studies, and 7 studies wherein androgen was applied topically via eye drops or systemically via oral or transdermal administration were included. The quality of these studies was assessed with the Cochrane Collaboration's tool for assessing risk of bias and methodological index for non-randomized studies. Most studies showed that androgen effectively improved dry eye-related symptoms and increased tear secretion. Furthermore, elderly men and peri-menopausal women with lower levels of circulating androgens responded better to ART. However, one study involving patients with Sjögren's syndrome showed no improvement in the ART group compared to the placebo control, or to the baseline level. Adverse effects were also common but limited to mild skin problems. In conclusion, androgen is a potential treatment for dry eye disease, especially for people with primary androgen deficiency. Short-term application is relatively safe.

Morphological Changes of Meibomian Glands in Men With Benign Prostate Hyperplasia

PURPOSE

Meibomian glands are subject to regulation by sex hormones. We have now investigated the possible relation between benign prostate hyperplasia (BPH) and meibomian gland dysfunction (MGD).

METHODS

Men diagnosed with BPH and receiving treatment with tamsulosin and age-matched male control subjects who attended Itoh Clinic, Saitama, Japan, were enrolled. An ocular symptom score, lid margin abnormality score, and superficial punctate keratopathy score as well as the meiboscore (0-6), meibum grade, breakup time of the tear film, and Schirmer test values were evaluated. Male pattern baldness was also graded according to the Hamilton-Norwood scale.

RESULTS

Forty-four eyes of 44 men with BPH (mean age ± SD, 76.1 ± 2.2 years) and 46 eyes of 46 control subjects (mean age ± SD, 75.3 ± 6.2 years) were enrolled. The meiboscore in the BPH group (4.5 ± 1.4) was significantly higher than that in the control group (1.8 ± 1.5, P < 0.0001). Breakup time of the tear film was significantly shorter (3.6 ± 1.7 vs. 5.6 ± 2.5 seconds, P < 0.0001), and Schirmer test value was significantly smaller (9.8 ± 4.8 vs. 13.3 ± 8.0 mm, P = 0.048) in the BPH group than that in the control group. Other ocular parameters did not differ significantly between the 2 groups. The proportion of men with androgenic alopecia was also higher in the BPH group than that in the control group.

CONCLUSIONS

BPH was associated with meibomian gland loss and instability of the tear film as well as with the presence of androgenic alopecia.

Association of meibomian gland architecture and body mass index in a pediatric population

PURPOSE

To determine if meibomian gland architecture in a pediatric population is impacted by body mass index (BMI).

METHODS

Prospective evaluation of 175 eyes of 175 pediatric patients from two clinics. Demographic and clinical information were reviewed. Symptoms of dry eye were assessed with the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Meibography was performed and grading of images was performed by a masked rater using a previously validated 5-point meiboscale (0-4) for gland atrophy and a 3-point score (0-2) for gland tortuosity.

RESULTS

175 eyes of 175 participants aged 4-17 years (11.6 ± 3.7 years) were imaged. The mean meiboscore was 0.82 ± 0.94 (range 0-4) and the mean gland tortuosity score was 0.53 ± 0.70 (range 0-2). Ninety-six patients (56%) showed evidence of gland atrophy (meiboscore greater than 0) and the majority of patients (n=50, 29%) had a gland tortuosity score of 1. The mean BMI was 20.5 ± 4.86 kg/m² with 39.4% of patients (n = 69) above the 85th percentile. BMI percentile was not found to be a significant predictor of a meiboscore greater than 0 (odds ratio (OR) 1.004 95% confidence interval (CI) (0.99-1.10, p = 0.41). However, BMI percentile was found to be a significant predictor of gland tortuosity score (OR 1.01 95% CI (1.00-1.02), p = 0.02). Patients with BMI percentiles between 41 and 60 were 3.79 times more likely to have a gland tortuosity score of greater than 0 than patients with BMI percentiles between 0 and 20 (OR 3.789 CI (1.17-12.24)). No significant associations were found between age, race, or sex and meiboscore or tortuosity. There was a trend towards reduction in lipid layer thickness with increasing BMI percentile (p = 0.028, r² = 0.04).

CONCLUSION

In this pediatric population, there was an association between meibomian gland tortuosity and higher percentiles of BMI. Future studies are needed to elucidate the pathogenesis of meibomian gland tortuosity and atrophy in pediatric patients.

Health Risks Associated with Long-Term Finasteride and Dutasteride Use: It's Time to Sound the Alarm

5α-dihydrotestosterone (5α-DHT) is the most potent natural androgen. 5α-DHT elicits a multitude of physiological actions, in a host of tissues, including prostate, seminal vesicles, hair follicles, skin, kidney, and lacrimal and meibomian glands. However, the physiological role of 5α-DHT in human physiology, remains questionable and, at best, poorly appreciated. Recent emerging literature supports a role for 5α-DHT in the physiological function of liver, pancreatic β-cell function and survival, ocular function and prevention of dry eye disease and kidney physiological function. Thus, inhibition of 5α-reductases with finasteride or dutasteride to reduce 5α-DHT biosynthesis in the course of treatment of benign prostatic hyperplasia (BPH) or male pattern hair loss, known as androgenetic alopecia (AGA) my induces a novel form of tissue specific androgen deficiency and contributes to a host of pathophysiological conditions, that are yet to be fully recognized. Here, we advance the concept that blockade of 5α-reductases by finasteride or dutasteride in a mechanism-based, irreversible, inhabitation of 5α-DHT biosynthesis results in a novel state of androgen deficiency, independent of circulating testosterone levels. Finasteride and dutasteride are frequently prescribed for long-term treatment of lower urinary tract symptoms in men with BPH and in men with AGA. This treatment may result in development of non-alcoholic fatty liver diseases (NAFLD), insulin resistance (IR), type 2 diabetes (T2DM), dry eye disease, potential kidney dysfunction, among other metabolic dysfunctions. We suggest that long-term use of finasteride and dutasteride may be associated with health risks including NAFLD, IR, T2DM, dry eye disease and potential kidney disease.

Dry eye signs and symptoms in aromatase inhibitor treatment and the relationship with pain

PURPOSE

Aromatase inhibitors (AIs) limit the synthesis of oestrogen in peripheral tissues thus lowering levels of oestrogen. The primary aim was to evaluate whether women treated with AIs have altered dry eye symptoms and signs. A sub-aim was to investigate whether symptoms of dry eye in postmenopausal women were associated with symptoms of non-eye pain, ocular pain and self-rated pain perception.

METHODS

This cross-sectional, observational, single visit study recruited 56 postmenopausal women (mean age 64.1 + 7.9 years) and 52 undergoing AI treatment (mean age 66.6 + 9.0). Ocular symptoms (OSDI, MGD14) and pain questionnaires (PSQ, OPAS) were administered and signs of dry eye and meibomian gland dysfunction were evaluated.

RESULTS

Almost half of each group reported dry eye symptoms, defined as OSDI>12 (48% control, 46% AI). The PSQ score was significantly higher in the AI group (p = 0.04). Neither frequency or severity of dry eye (or MGD) symptoms scores were significantly different between groups. In the AI group, meibomian gland expressibility score was worse (p = 0.003); there were no differences in any other signs. Higher OSDI scores were associated with higher OPAS eye-pain scores (r = 0.49, p < 0.001), but not OPAS non-eye pain (r = 0.09, p = 0.35). Pain perception (PSQ) showed a moderate positive association with OPAS eye-pain (r = 0.30, p = 0.003).

CONCLUSIONS

In this study elevated ocular symptoms were observed in both the AI treated and the untreated groups, with no difference between the groups. Women undergoing AI treatment for early stage breast cancer had worse meibum expressibility score and increased pain perception compared to an untreated group of women.

Management of meibomian gland dysfunction: a review

Meibomian gland dysfunction is the leading cause of evaporative dry eye disease and is one of the most common conditions encountered by eye care providers. The disorder is characterized by obstruction of the meibomian gland terminal ducts and/or changes in their glandular secretion, resulting in changes in tear film stability, inflammation, and symptoms of irritation. There is no gold standard treatment for meibomian gland dysfunction, but rather a diversity of options. Conservative measures include warm compresses and lid hygiene, but there is growing interest and need for medical treatments and procedures. Potential medical treatments include antibiotics, nonsteroidal and steroidal anti-inflammatory agents, essential fatty acid supplementation, hormone therapy, and control of Demodex infestation. Procedures include intraductal meibomian gland probing, the use of electronic heating devices, intense pulsed light therapy, and intranasal neurostimulation. We provide an update on meibomian gland dysfunction treatments based on recent studies.

Meibomian Gland Dysfunction in Primary and Secondary Sjögren Syndrome

PURPOSE

We hypothesized that women with primary (pSS) and secondary Sjögren syndrome (sSS; with systemic lupus erythematosus [SLE] or rheumatoid arthritis [RA]) have meibomian gland dysfunction (MGD). We sought to test our hypothesis.

METHODS

Subjects with pSS, sSS + SLE, sSS + RA, and non-SS-related MGD were recruited from the Sjögren's Syndrome Foundation or outpatient clinics at Tufts University School of Dental Medicine or Brigham and Women's Hospital. The control population was recruited from the Greater Boston area. After providing written informed consent, the subjects underwent an eye examination and/or completed two questionnaires that assess symptoms of dry eye disease (DED).

RESULTS

Our results demonstrate that pSS and sSS patients have MGD. These subjects had meibomian gland orifice metaplasia, an increased number of occluded meibomian gland orifices, and a reduced quality of meibomian gland secretions. Further, patients with pSS, sSS + SLE, sSS + RA, and MGD had significant alterations in their tear film, lid margin, cornea, and conjunctiva. Symptoms of DED were increased ∼10-fold in all pSS, sSS, and MGD groups relative to controls.

CONCLUSIONS

Our findings support our hypothesis and show that individuals with pSS, sSS + SLE, and sSS + RA have MGD. In addition, our study indicates that patients with pSS and sSS have both aqueous-deficient and evaporative DED.

Morphology and Function of Meibomian Glands and Other Tear Film Parameters in Junior High School Students

Purpose:

We measured tear film parameters, including the morphology and function of meibomian glands, in junior high school students at 15 years of age.

Methods:

A total of 111 eyes of 111 students (56 males and 55 females) were enrolled in the study. The ocular symptom score (0–14), after-school study time, lipid layer thickness (LLT) of the tear film, partial blink rate, lid margin abnormalities (0–4), tear film breakup time, corneal and conjunctival epithelial damage (fluorescein staining score, 0–9), meiboscore as determined by noncontact meibography (0–6), Schirmer test value, and meibum grade (0–3) were determined. The relationships between parameters were evaluated with the Spearman correlation coefficient (ρ).

Results:

The meiboscore was 2.8 ± 1.2, and the meibum grade was 1.8 ± 1.2. The meiboscore significantly correlated with the meibum grade (ρ = 0.272, P = 0.004), Schirmer test value (ρ = −0.220, P = 0.021), and LLT (ρ = −0.264, P = 0.005). The breakup time significantly correlated with LLT (ρ = 0.261, P = 0.006), meibum grade (ρ = −0.338, P < 0.001), and fluorescein staining score (ρ = −0.214, P = 0.025). The partial blink rate significantly correlated with the Schirmer test value (ρ = −0.240, P = 0.011). The meiboscore (P < 0.001) and meibum grade (P = 0.032) were significantly greater in males than in females.

Conclusions:

The morphology and function of meibomian glands are altered even at 15 years of age, with the changes being more prominent in males than in females.

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.

TFOS DEWS II Sex, Gender, and Hormones Report

One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.

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.

TFOS DEWS II Tear Film Report

The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership.

Meibomian glands, meibum, and meibogenesis

Meibum is a lipid-rich secretion that is produced by fully differentiated meibocytes in the holocrine Meibomian glands (MG) of humans and most mammals. The secretion is a part of a defense mechanism that protects the ocular surface from hazardous environmental factors, and from desiccation. Meibomian lipids that have been identified in meibum are very diverse and unique in nature. The lipid composition of meibum is different from virtually any other lipid pool found in the human body. In fact, meibum is quite different from sebum, which is the closest secretion that is produced by anatomically, physiologically, and biochemically related sebaceous glands. However, meibum of mice have been shown to closely resemble that of humans, implying similar biosynthetic mechanisms in MG of both species. By analyzing available genomic, immunohistochemical, and lipidomic data, we have envisioned a unifying network of enzymatic reactions that are responsible for biosynthesis of meibum, which we call meibogenesis. Our current theory is based on an assumption that most of the biosynthetic reactions of meibogenesis are catalyzed by known enzymes. However, the main features that make meibum unique - the ratio of identified classes of lipids, the extreme length of its components, extensive ω-hydroxylation of fatty acids and alcohols, iso- and anteiso-branching of meibomian lipids (e.g. waxes), and the presence of rather unique complex lipids with several ester bonds - make it possible that either the activity of known enzymes is altered in MG, or some unknown enzymes contribute to the processes of meibogenesis, or both. Studies are in progress to elucidate meibogenesis on molecular level.

A Metabolome-Wide Study of Dry Eye Disease Reveals Serum Androgens as Biomarkers

PURPOSE

To test the association between serum metabolites and dry eye disease (DED) using a hypothesis-free metabolomics approach.

DESIGN

Cross-sectional association study.

PARTICIPANTS

A total of 2819 subjects from the population-representative TwinsUK cohort in the United Kingdom, with a mean age of 57 years (range, 17-82 years).

METHODS

We tested associations between 222 known serum metabolites and DED. All subjects underwent nontargeted metabolomic analysis of plasma samples using gas and liquid chromatography in combination with mass spectrometry (Metabolon Inc., Durham, NC). Dry eye disease was defined from the validated Short Questionnaire for Dry Eye Syndrome (SQDES) as a previous diagnosis of DED by a clinician or "often" or "constant" symptoms of dryness and irritation. Analyses were performed with linear mixed effect models that included age, BMI, and sex as covariates, corrected for multiple testing.

MAIN OUTCOME MEASURES

Primary outcome was DED as defined by the SQDES, and secondary outcomes were symptom score of DED and a clinical diagnosis of DED.

RESULTS

Prevalence of DED as defined by the SQDES was 15.5% (n = 436). A strong and metabolome-wide significant association with DED was found with decreased levels of the metabolites androsterone sulfate (P = 0.00030) and epiandrosterone sulfate (P = 0.00036). Three other metabolites involved in androgen metabolism, 4-androsten-3beta,17beta-diol disulfate 1 and 2, and dehydroepiandrosterone sulfate, were the next most strongly associated of the 222 metabolites, but did not reach metabolome-wide significance. Dryness and irritation symptoms, as opposed to a clinical diagnosis, were particularly strongly associated with decreased androgen steroid metabolites, with all reaching metabolome-wide significance (androsterone sulfate, P = 0.000000029; epiandrosterone sulfate, P = 0.0000040; 4-androsten-3beta,17beta-diol disulfate 1, P = 0.000016; 4-androsten-3beta,17beta-diol disulfate 2, P = 0.000064; and dehydroepiandrosterone sulfate, P = 0.00011). Of these 5 androgens, epiandrosterone sulfate (P = 0.0076) was most associated with 2-year incidence of clinician-diagnosed DED. In addition, we found decreased glycerophosphocholines to be associated with DED, although not at metabolome-wide significance.

CONCLUSIONS

This hypothesis-free metabolomic approach found decreased serum androgens to be highly associated with DED and adds important evidence to the growing body of research that links androgens to ocular surface disease and DED.

Anterior Segment Findings in Women with Polycystic Ovary Syndrome

Objectives:

This study aimed to investigate the anterior segment in women with polycystic ovary syndrome (PCOS) and to compare them with those of healthy reproductive-age female volunteers.

Materials and Methods:

The study included 50 right eyes of 50 women with PCOS (group 1) and 50 right eyes of 50 healthy women (group 2). Intraocular pressure, Schirmer’s test, tear film break-up time and central corneal thickness were evaluated in all subjects. Correlations between serum hormone (estradiol and testosterone) levels and observed findings were also investigated.

Results:

Mean central corneal thickness values were significantly higher in the PCOS group (p=0.001). The mean intraocular pressures values were similar between the two groups (p=0.560). Schirmer’s test results and tear film break-up time values were significantly lower in the PCOS group (p=0.001 and p=0.001 respectively). Serum estradiol levels were moderately positively correlated with mean central corneal thickness (r=0.552), weakly positively correlated with intraocular pressure (r=0.351) and weakly negatively correlated with tear film break-up time (r=-0.393). Serum free testosterone levels were weakly correlated with intraocular pressure (r=0.342) and central corneal thickness (r=0.303), and showed weak negative correlations with Schirmer’s test results (r=-0.562) and tear film break-up time (r=-0.502).

Conclusion:

PCOS leads to physiological and structural changes in the eye. Dry eye symptoms were more severe and central corneal thickness measurements were greater in patients with PCOS. Those are correlated serum testosterone and estradiol levels.

Evaluation of Meibomian Gland Dysfunction in Polycystic Ovary Syndrome and Obesity

Purpose/Aim of the study: The purpose of this study was to evaluate the interaction between Polycystic ovary syndrome (PCOS) and Meibomian gland dysfunction (MGD) and obesity, to reveal whether there is a correlation between the testosterone levels and body-mass index (BMI) levels and the dry-eye complaints of these patients.

MATERIAL AND METHODS

The study included 92 patients with PCOS and 52 healthy patients from March 2013 to March 2014. All patients underwent a physical examination, pelvic ultrasound, and clinical and biochemical tests, including free testosterone levels to confirm the diagnosis of PCOS. The BMIs of all subjects were recorded. In addition, the presence of posterior blepharitis, as an indicator of MGD, was recorded. All patients underwent the dry-eye tests including Schirmer 1 and tear film break-up time (BUT). Complaints of dry-eye of the patients were evaluated with the ocular surface disease index (OSDI) questionnaire. The scores of both groups were compared.

RESULTS

The presence of MGD was 72.82% in the PCOS group and 61.53% in the control group. There was no correlation between the testosterone levels and study parameters in both groups. BUT levels negatively correlated with BMI in subjects without PCOS (r = -0.520, p = 0.001), whereas positively correlated with MGD and OSDI scores (r = 0.610, p = 0.632; p = 0.001, p = 0.001; respectively).

CONCLUSION

Tear film instability due to MGD is common in PCOS and in subjects with high BMI. The MGD in PCOS patients is independent of the BMI.

Smoking and the risk of dry eye: a Meta-analysis

AIM

To collect the evidence to estimate the correlation between smoking and the incidence of dry eye.

METHODS

The PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL, last issue), CBM (Chinese BioMedical Literature Database), and CNKI (China National Knowledge Infrastructure/Chinese Academic Journals full-text Database) were searched for eligible studies published from January 1964 to December 2015 to investigate the association of smoking with the risk of dry eye. The odds ratio (OR) and 95% confidence interval (CI) were summarized and calculated. The extracted studies were pooled by the fixed-effects model or a random-effects model.

RESULTS

Two cohort studies and eight cross-sectional surveys were included in our Meta-analysis. There was no statistically significant relationship between current (OR=1.32; 95% CI: 0.99-1.76; P=0.055) or ever smoking (OR=1.12; 95% CI: 0.98-1.28; P=0.107) and the risk of dry eye among the studies, even when age and gender were adjusted (OR=1.16; 95% CI: 0.83-1.64; P=0.383). In the sensitivity analysis in which only general population were included, the association was significant between smoking and dry eye (OR=1.50; 95% CI: 1.08-2.09; P=0.016).

CONCLUSION

This Meta-analysis suggests that smoking may associate with the risk of dry eye in general population.

Effects of Sex Hormones on Ocular Surface Epithelia: Lessons Learned From Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine abnormality in women of reproductive age. Although its clinical consequences have been known for a long time to extend beyond the reproductive system, with type-2 diabetes and obesity being the most common, the involvement of the ocular surface in PCOS has been described only more recently. The ocular surface is a morphofunctional unit comprising eyelid margin, tear film, cornea, and conjunctiva. Increasing evidence indicates that these structures are under a sex hormone control and relevant diseases such as ocular allergy and dry eye are often caused by alterations in circulating or local steroid hormones levels. Novel treatments targeting sex hormone receptors on ocular surface epithelial cells are also being developed. In this review we aim to describe the current knowledge on the effects of sex hormones at the ocular surface, with a special focus on the effects of androgen imbalance in PCOS.

Efficacy of 1% carboxymethylcellulose sodium for treating dry eye after phacoemulsification: results from a multicenter, open-label, randomized, controlled study

BACKGROUND

For patients who experience dry eye after phacoemulsification, vision and quality of life can significantly deteriorate. In this study, the efficacy and safety of carboxymethylcellulose sodium (CMC) 1% ophthalmic solution combined with conventional therapy in treating dry eye signs and symptoms after phacoemulsification were evaluated.

METHODS

In this prospective, multicenter, open-label, controlled study, 180 patients with age-related cataract were randomized to treatment with conventional therapy plus CMC 1% (n = 90) or to conventional therapy only (control group, n = 90) after phacoemulsification and intraocular lens implantation. Tear breakup time (TBUT), the Schirmer test with anesthesia, and fluorescein and lissamine green staining were performed. The Ocular Surface Disease Index (OSDI) questionnaire and a patient subjective symptom evaluation were administered preoperatively (baseline) and postoperatively at 7 and 30 days.

RESULTS

TBUT was significantly longer in the treatment group compared with the control group at day 7 (8.5 ± 5.5 versus 6.6 ± 3.8 s; P = 0.0475) and day 30 (9.0 ± 5.9 versus 6.7 ± 4.8 s; P = 0.0258) after surgery. Compared with baseline, TBUT significantly increased in patients in the treatment group (P < 0.001 at both day 7 and day 30) with a presurgical diagnosis of dry eye, but significantly decreased in patients in the control group (P < 0.02 at both day 7 and day 30) with no prior diagnosis of dry eye. Fluorescein and lissamine staining, OSDI questionnaire and subjective symptom scores all improved from baseline, with no significant differences between the two groups. No significant differences in tolerability and safety were observed between the group receiving CMC and conventional therapy, and those receiving conventional therapy only.

CONCLUSION

Treatment with CMC 1% can provide significant improvement in tear film stability after phacoemulsification for age-related cataract.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02028754 (Date of registration: Jan. 6, 2014).

Sex-steroid imbalance in females and dry eye

Dry eye (DE) is a multifactorial disorder of the ocular surface unit that results in eye discomfort, visual disturbance and ocular surface damage. It is one of the most common complaints in daily ophthalmic practice. The risk of DE increases with age in both sexes, while its incidence is higher among females. In addition, the condition of menopause in aging women may also contribute to DE onset or worsening as a consequence of an overall hormonal imbalance. Sex hormones play a key role in ocular surface physiology and they impact differently on ocular surface tissues. Reduced estrogen levels were historically thought to be responsible in age-related DE onset but more recent investigations have reconsidered the role of androgens that are present and exert a protective function on the ocular surface. Hormone levels themselves, withdrawal changes in hormone levels, and the changes in hormone-receptor responsiveness are all important factors but it remains to be fully elucidated how estrogen or androgen insufficiency act alone or together in a combined imbalance or interplay to raise the risk of disease. The purpose of this review is to briefly outline current scientific evidence on the influence of androgens and estrogens, on the Lachrymal and Meibomian glands and on ocular surface epithelia including conjunctival goblet cells during reproductive and menopausal periods. The role of sex steroids is also discussed in relation to the pathogenesis of different forms of DE and Sjogren's syndrome (SS). The impact of systemic hormone therapy (HT) in DE post-menopausal women still appears as a controversial issue, despite the many clinical studies. Finally, the outcomes of topical applications of steroid-based products are summarized, underlying the need for potential (tear) biomarker(s) in the rationale of DE-targeted therapy.

Androgen deficiency and dry eye syndrome in the aging male

PURPOSE

To evaluate the relationship between androgen levels and subjective and objective measures of dry eye syndrome (DES).

METHODS

A total of 263 male patients from the Miami Veterans Affairs Medical Center eye clinic aged ≥50 were recruited for this prospective cross-sectional study. Patients completed Dry Eye Questionnaire 5, underwent tear film evaluation, and had serum androgen levels measured. The correlations between androgen levels, DES composite scores, DES symptoms, and global, lipid, and aqueous tear film parameters were evaluated.

RESULTS

Two hundred sixty-three patients with a mean age of 69 (50-95) were examined. There was no linear association between composite DES scores (generated using latent class analysis) and androgen levels. However, eyes with high DES scores (0.95-1.0) had higher levels of sex hormone-binding globulin (P = 0.03) and lower levels of dehydroepiandrosterone sulfate (DHEAS) (P = 0.02), androstenedione (A) (P = 0.02), and androstane-3α,17β-diol glucuronide (P = 0.03) compared to eyes with intermediate (0.05-0.95) or low (0-0.05) scores. There were no strong correlations between tear film measures and androgen levels. Regarding global parameters, a weak inverse correlation was found between corneal staining and A (r = -0.17, P = 0.009). For lipid parameters, a weak correlation existed between tear breakup time (TBUT) and A (r = 0.15, P = 0.02). When considering aqueous and lipid deficiency independently, the association between TBUT and A existed only with aqueous tear deficiency (r = 0.66, P = 0.002). Regarding aqueous parameters, a weak correlation existed between Schirmer test and DHEAS (r = 0.13, P = 0.047) and A (r = 0.21, P = 0.001).

CONCLUSIONS

There was a weak correlation between higher levels of androstenedione and healthier global, lipid, and aqueous tear film parameters.

The neurobiology of the meibomian glands

This article compiles research regarding the neuroanatomy of the meibomian glands and their associated blood vessels. After a review of meibomian gland morphology and regulation via hormones, a case for innervation is made based on anatomical findings whereby the nerves lack a myelin sheath and Schwann cells. The localization and co-localization of dopamine beta-hydroxylase, tyrosine hydroxylase, neuropeptide Y, vasoactive intestinal polypeptide, calcitonin gene-related peptide, and substance P are explored with emphasis on differences that exist between species. The presence of the various neuropeptides/neurotransmitters adjacent to the meibomian gland versus the vasculature associated with the meibomian gland is documented so that conclusions can be made with regard to direct and indirect effects. Research regarding the presence of receptors and receptor proteins for these neuropeptides is documented. Evidence supporting the influence of certain neurotransmitters and/or neuropeptides on the meibomian gland is given based on research that correlates changes in meibomian gland morphology and/or tear film with changes in neurotransmitter and/or neuropeptide presence. Conclusions are drawn related to direct and indirect regulation and differences between the various nervous systems.

Sex hormones and the dry eye

The greater prevalence of dry eye in women compared to men suggests that sex hormones may have a role in this condition. This review aims to present evidence for how sex hormones may affect the ocular structures involved in the production, regulation and maintenance of the normal tear film. It is hypothesised that hormone changes alter the homeostasis of the ocular surface and contribute to dry eye. Androgens impact on the structure and function of the meibomian and lacrimal glands and therefore androgen deficiency is, at least in part, associated with the aetiology of dry eye. In contrast, reports of the effects of oestrogen and progesterone on these ocular structures and on the conjunctiva are contradictory and the mechanisms of action of these female-specific sex hormones in the eye are not well understood. The uncertainty of the effects of oestrogen and progesterone on dry eye symptoms is reflected in the controversial relationship between hormone replacement therapy and the signs and symptoms of dry eye. Current understanding of sex hormone influences on the immune system suggests that oestrogen may modulate a cascade of inflammatory events, which underlie dry eye.

A randomized controlled trial of omega-3 fatty acids in dry eye syndrome

AIM

To evaluate the role of dietary supplementation of omega-3 fatty acids in dry eye syndrome.

METHODS

A prospective, interventional, placebo controlled, double blind randomized trial was done at two referral eye centers. Two hundred and sixty-four eyes of patients with dry eye were randomized to receive one capsule (500mg) two times a day containing 325mg EPA and 175mg DHA for 3 months (omega-3 group). The omega-3 group was compared to a group of patients (n=254) who received a placebo (placebo group). There were 4 patient visits (at baseline, 1 month, 2 months and 3 months). On each visit, recording of corrected distance visual acuity (CDVA), slit lamp examination and questionnaire based symptom evaluation and scoring was done. A symptomatic score of 0-6 was mild, 6.1-12 moderate and 12.1-18 severe dry eye. Response to intervention was monitored by routine tear function tests like Schirmer I test, tear film break-up time (TBUT), Rose Bengal staining and most notably, conjunctival impression cytology.

RESULTS

Sixty-five percent of patients in the omega-3 group and 33% of patients in placebo group had significant improvement in symptoms at 3 months (P=0.005). There was a significant change in both Schirmer's test value and TBUT values in the omega-3 group (P<0.001), both comparisons. However, there was a larger drift in TBUT values in omega-3 than the placebo group, in comparison to Schirmer's test values. The mean TBUT score was 2.54±2.34 in the omega-3 group and 0.13±0.16 in placebo group, respectively. The mean reduction in symptom score in omega-3 group was 2.02±0.96 as compared to 0.48±0.22 in placebo group (P<0.001). Despite a slight increase mean score, the Schirmer scores did not correlate well with symptomatic improvement.

CONCLUSION

Omega-3 fatty acids have a definite role for dry eye syndrome. The benefit seems to be more marked in conditions such as blepharitis and meibomian gland disease. The role of omega fatty acids in tear production and secretion needs further evaluation.

[Testosterone reduces the expression of keratinization-promoting genes in murine Meibomian glands]

BACKGROUND

Extensive keratinization appears to play a major role in the dysfunction of the Meibomian gland. This article presents the potential impact of androgens on limiting keratinization in this tissue, thus, contributing to normal Meibomian gland function and a healthy ocular surface.

MATERIALS AND METHODS

Orchidectomized mice were systemically treated with either testosterone or placebo for 2 weeks. The mRNA was then extracted from the Meibomian glands and differential gene expression was investigated by microarray hybridization and evaluation with GeneSifter software as well as gene ontology information from the Gene Ontology (GO) Consortium.

RESULTS

By z-score calculations, keratinization was the most significantly gene ontology term influenced by testosterone based on down-regulated genes in the mouse Meibomian gland. In particular, under the influence of testosterone the genes coding for small proline-rich protein (Sprr) 2a, Sprr 2b, Sprr 3, keratins 6a and 17 and periplakin were significantly down-regulated, while Sprr 1a and Sprr 2f were significantly up-regulated.

CONCLUSIONS

Testosterone down-regulates the expression of genes promoting keratinization in the Meibomian gland. This may help to prevent Meibomian gland dysfunction by limiting excessive keratinization of this tissue and the adjacent lid margins. The findings elucidate, at least in part, the beneficial impact of androgens on Meibomian gland function and thus on th e health of the ocular surface.

Aging and dry eye disease

Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD.

Age-related changes in tear menisci imaged by optical coherence tomography

PURPOSE

To determine age-related changes of tear menisci in healthy subjects and to compare tear variables between age-matched normals and dry eye subjects.

METHODS

Anterior segment optical coherence tomography was used to measure upper and lower tear menisci in healthy subjects (n = 197, 8-83 years) and in age-matched dry eye patients (n = 38, 19-72 years). Measured tear variables included the height and area of the tear meniscus. Tear meniscus volumes were calculated based on the cross-sectional areas of the tear menisci and the eyelid lengths. The age-related decrease rates of the tear menisci were also calculated.

RESULTS

There were significant negative correlations between age and all tear meniscus dimensions (r ranged from -0.649 to -0.753; p < 0.05) in the healthy group. The rate of decrease for the total tear meniscus volume in healthy subjects was 1.0% per year. Compared with age-matched healthy subjects, the height, cross-sectional area, and volume of the upper and lower tear menisci in dry eye subjects were significantly smaller (p < 0.05).

CONCLUSIONS

Tear menisci decreased with age in the healthy group. The variables in age-matched dry eye subjects were significantly lower than those in the healthy group.

Effects of age and dysfunction on human meibomian glands

OBJECTIVE

To identify age-related changes in human meibomian glands that may be associated with meibomian gland dysfunction (MGD).

METHODS

Excess eyelid tissue from 36 patients (age range, 18-95 years, 19 female, 17 male) who underwent canthoplasty procedures were used. Dermatologic history, age, and presence of MGD were recorded. Samples were frozen, sectioned, and stained with specific antibodies against peroxisome proliferator-activated receptor γ (PPARγ) to identify meibocyte differentiation, Ki67 nuclear antigen to identify cycling cells, and CD45 to identify inflammatory cell infiltration.

RESULTS

Staining for PPARγ showed cytoplasmic and nuclear localization in the 2 youngest subjects (ages, 18 and 44 years). Older individuals (>60 years) showed predominantly nuclear staining, with cytoplasmic staining limited to the basal acinar cells in 17 of 31 subjects. The number of Ki67 positively stained basal cells were significantly elevated in the younger compared with older subjects based on linear regression analysis (r(2) = 0.35; P < .001). There was also a significant correlation between MG expression grade and CD45 cell infiltration (r = 0.414; P = .05).

CONCLUSIONS

These results indicate that aging human meibomian glands show decreased meibocyte differentiation and cell cycling that is associated with the development of MGD. Findings also suggest that altered PPARγ signaling may lead to acinar atrophy and development of an age-related hyposecretory MGD.

CLINICAL RELEVANCE

Meibomian gland dysfunction and evaporative dry eye are common age-related eyelid disorders. Understanding the underlying mechanism of MGD may lead to the development of novel therapeutic strategies to treat this disease.

Changes in gene expression in human meibomian gland dysfunction

PURPOSE

Meibomian gland dysfunction (MGD) may be the leading cause of dry eye syndrome throughout the world. However, the precise mechanism(s) underlying the pathogenesis of this disease is unclear. This study was conducted to identify meibomian gland genes that may promote the development and/or progression of human MGD.

METHODS

Lid tissues were obtained from male and female MGD patients and age-matched controls after eyelid surgeries (e.g., to correct entropion or ectropion). Meibomian glands were isolated and processed for RNA extraction and the analysis of gene expression.

RESULTS

The results show that MGD is associated with significant alterations in the expression of almost 400 genes in the human meibomian gland. The levels of 197 transcripts, including those encoding various small proline-rich proteins and S100 calcium-binding proteins, are significantly increased, whereas the expression of 194 genes, such as claudin 3 and cell adhesion molecule 1, is significantly decreased. These changes, which cannot be accounted for by sex differences, are accompanied by alterations in many gene ontologies (e.g., keratinization, cell cycle, and DNA repair). The findings also show that the human meibomian gland contains several highly expressed genes that are distinct from those in an adjacent tissue (i.e., conjunctival epithelium).

CONCLUSIONS

The results demonstrate that MGD is accompanied by multiple changes in gene expression in the meibomian gland. The nature of these alterations, including the upregulation of genes encoding small proline-rich proteins and S100 calcium-binding proteins, suggest that keratinization plays an important role in the pathogenesis of MGD.

Lipidomics of human Meibomian gland secretions: Chemistry, biophysics, and physiological role of Meibomian lipids

Human Meibomian gland secretions (MGS) are a complex mixture of diverse lipids that are produced by Meibomian glands that are located in the upper and the lower eyelids. During blinking, MGS are excreted onto the ocular surface, spread and mix with aqueous tears that are produced by lachrymal glands, and form an outermost part of an ocular structure called "the tear film" (TF). The main physiological role of TF is to protect delicate ocular structures (such as cornea and conjunctiva) from desiccating. Lipids that are produced by Meibomian glands are believed to "seal" the aqueous portion of TF by creating a hydrophobic barrier and, thus, retard evaporation of water from the ocular surface, which enhances the protective properties of TF. As lipids of MGS are interacting with underlying aqueous sublayer of TF, the chemical composition of MGS is critical for maintaining the overall stability of TF. There is a consensus that a small, but important part of Meibomian lipids, namely polar, or amphiphilic lipids, is of especial importance as it forms an intermediate layer between the aqueous layer of TF and its upper (and much thicker) lipid layer formed mostly of very nonpolar lipids, such as wax esters and cholesteryl esters. The purpose of this review is to summarize the current knowledge on the lipidomics of human MGS, including the discussions of the most effective modern analytical techniques, chemical composition of MGS, biophysical properties of Meibomian lipid films, and their relevance for the physiology of TF. Previously published results obtained in numerous laboratories, as well as novel data generated in the author's laboratory, are discussed. It is concluded that despite a substantial progress in the area of Meibomian glands lipidomics, there are large areas of uncertainty that need to be addressed in future experiments.