Sex steroids, the meibomian gland and evaporative dry eye

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.

Features and influences on the normal tear evaporation rate

Tear evaporation is a normal physiological phenomenon that has an important role in regulating blink activity and tear production. An altered tear evaporation rate (TER) is a defining characteristic of evaporative dry eye disease (DED), and the measurement of tear evaporation is a useful clinical test for diagnosis. Reported values for a normal TER cover a broad range, which may be due to the influence of ocular, environmental, and systemic factors. For improved disease diagnosis, a fuller understanding of the normal TER range is essential. This paper reports on a literature review of the current knowledge of these normal influences on TER.

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.

Effects of hormonal contraceptives on dry eye disease: a population-based study

BACKGROUND

Hormonal contraceptives (HCs) are a known risk factor for dry eye disease (DED), yet the relationship between HCs use and DED in women of child-bearing age remains debatable. The aim of this study was to determine the association between HCs and DED in females of reproductive age.

METHODS

This was a retrospective cohort study using data from IQVIA's electronic medical record (IQVIA, USA). 4,871,504 women (age 15-45) between 2008 and 2018 were followed to the first diagnosis of DED as defined by an ICD-9/10 code. DED cases also required at least two prescriptions of cyclosporine or lifitegrast topical drops within 60 days of the first code. The date of the first code was designated as the index date. Regular HCs users needed to have at least two prescriptions in both the first year and second year prior to the index date. For each case, five controls were selected and matched to cases by age and follow-up time. A conditional logistic regression model was used to adjust for confounders of DED and to calculate odds ratios (ORs).

RESULTS

HCs users were at a higher risk for DED than non-users. Regular users of HCs were more likely to develop DED (ORs = 2.73, 95% CI [2.21-3.73]) than irregular users. Those who used a greater number of HCs were at a higher risk for DED.

CONCLUSIONS

This study indicates an increased risk of DED with HCs use in women of child-bearing age.

Meibomian gland dysfunction is highly prevalent among first-time visitors at a Norwegian dry eye specialist clinic

To investigate the prevalence of meibomian gland dysfunction (MGD) in patients presenting with subjective dry eye-related symptoms at their first-time consultation in a Norwegian specialized ocular surface clinic. Additionally, to explore the accuracy of the ocular surface disease index score (OSDI) as an extensively applied tool to assess the severity of dry eye symptoms and MGD diagnosis. Patients with subjective dry eye-related complaints (n = 900) attending the clinic for the first time, from 2012 to 2016, were included in the study. At the baseline, patients completed the OSDI questionnaire. Subsequently, objective clinical tests, including fluorescein break-up time (FBUT), Schirmer-I test, ocular surface staining (OSS), and meibomian gland function assessment using gland expressibility and meibum quality were performed. The association between MGD and its severity in relation to symptom severity defined by OSDI-score was examined. MGD was found in 93.8% of the study group. MGD prevalence was not significantly different between groups based on age (p = 0.302) or sex (p = 0.079). There was a significant association between severity of MGD and dry eye-related symptoms (p = 0.014). OSS was significantly higher in patients with severe symptoms (p = 0.031). Sensitivity and specificity of positive symptom-score (OSDI ≥ 13) for disclosing MGD were 85.5% and 30.4%, respectively. MGD was highly prevalent, not associated with age and sex. OSDI ≥ 13 had high sensitivity and high positive predictive value (PPV), but low specificity and negative predictive value (NPV) for disclosing MGD. This underscores the importance of meibomian gland assessment in patients with dry eye-related symptoms.

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.

Improvement of Evaporative Dry Eye With Meibomian Gland Dysfunction in Model Mice by Treatment With Ophthalmic Solution Containing Mineral Oil

Purpose

Meibomian gland dysfunction (MGD) is a major cause of evaporative dry eye. The purpose of this study is to assess the efficacy of a mineral oil-containing ophthalmic solution (MO) in mitigating the evaporative dry eye phenotypes in a mouse model in which fatty acid elongase Elovl1 is disrupted.

Methods

Elovl1-deficient mice were assessed in terms of number of plugged meibomian gland orifices, tear film breakup time (BUT), corneal fluorescein staining (CFS) score, tear quantity, and histology. The effects of the MO on the dry eye phenotypes were compared with those in groups not treated or treated with blank ophthalmic solution (BL).

Results

Untreated Elovl1-deficient mice exhibited dry eye phenotypes with MGD symptoms such as plugging of meibomian gland orifices (P = 0.002 compared with control mice), high CFS scores (P = 0.002), and shortened BUT (P < 0.001). Among three groups of Elovl1-deficient mice (MO treated, BL treated, and untreated), the MO-treated group exhibited fewer plugged orifices (MO treated, 7.6; BL treated, 10.5 [P = 0.033]; untreated, 13.0 [P < 0.001]), lower CFS scores (MO treated, 1.1; BL treated, 2.7 [P = 0.013]; untreated, 2.5 [P = 0.050]), and improved BUT (MO treated, 19.4 seconds; BL treated, 8.3 seconds [P = 0.098]; untreated, 1.5 seconds [P = 0.008]).

Conclusions

Elovl1-deficient mice exhibited multiple MGD symptoms, which were improved by MO.

Translational Relevance

Our findings reveal the usefulness of Elovl1-deficient mice as a model for dry eye with MGD and suggest the potential of mineral oil eye drops as a treatment for this condition.

Investigation of the effect of the dual orexin receptor antagonist almorexant on ophthalmological, spermatogenic, and hormonal variables in healthy male subjects

BACKGROUND/AIMS

The aim of this single-center, double-blind study was to investigate the effect of a 4-week once daily administration of 200 mg almorexant on tear film break-up time, spermatogenesis, hormone levels, and pancreatic elastase in stool in healthy male subjects.

METHODS

Almorexant 200 mg or matching placebo was administered in the evening for 4 weeks once daily to 56 healthy male subjects. Changes in ophthalmological variables, sperm composition, hormone levels, and pancreatic elastase levels in stool were evaluated periodically up to 8 weeks after discontinuation of drug administration. Blood samples for pharmacokinetic measurements were taken after 4 weeks to confirm compliance to study drug intake.

RESULTS

The results of this study revealed no treatment effects of almorexant, neither on tear film break-up time nor on other ophthalmological variables investigated during this study. Furthermore, spermatogenesis, hormones of the hypothalamic-pituitary-adrenal and -gonadal axes, and endocrine pancreatic secretion were shown to be not affected by a 4-week once daily administration of almorexant.

CONCLUSION

Almorexant was well tolerated and had no effect on the spectrum of pharmacodynamic variables assessed. Ophthalmology and testicular findings detected in preclinical studies were not observed in this clinical study. Therefore, these preclinical findings appear not to be relevant for humans and do not prevent from conducting larger clinical trials with either healthy subjects or patients.

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.

The effects of adjuvant hormonotherapy on tear functions in patients with breast cancer

PURPOSE

Aromatase inhibitors (anastrozole, letrozole) and selective estrogen receptor modulators (tamoxifen) are widely used as adjuvant hormonal therapy in women with hormone receptor-positive breast cancer. We aimed to evaluate the effects of oral adjuvant hormonotherapy on tear functions in patients with breast cancer.

METHODS

In this case-control study, we enrolled eligible patients with breast cancer who were receiving regular medical selective estrogen receptor modulator (tamoxifen, n:50), aromatase inhibitors (anastrozole, letrozole, n:50) and gender-matched healthy controls (n:50). Tear functions were measured and compared by the Schirmer test, fluorescein breakup time, corneal staining evaluated by Oxford grading scale and Ocular Surface Disease Index scores.

RESULTS

Mean age was 49.95 (± 9.2), 51.52 (± 7.2) and 51.91 (± 10.3) in tamoxifen, aromatase inhibitors groups and controls (p = 0.426). Mean duration of BC diagnosis (p = 0.536) and drug use (p = 0.417) was not significant between two groups. Ocular Surface Disease Index scores were lower (p < 0.001), and fluorescein breakup time measurements were higher (p < 0.001) in controls. Schirmer test scores were higher in controls than aromatase inhibitors group (p < 0.001). According to the scores of all measurements, the differences between aromatase inhibitors and tamoxifen groups were statistically significant (p < 0.001).

CONCLUSIONS

Our results demonstrated a high difference in all parameters in patients receiving aromatase inhibitors compared to tamoxifen group and controls. Aromatase inhibitors, which reduce estrogen levels in the blood, might affect the tear functions more than tamoxifen, which affects as antiestrogenic on estrogen receptors.

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.

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.

Morphological Evaluation of Meibomian Glands in Children and Adolescents Using Noncontact Infrared Meibography

PURPOSE

To compare, in vivo, differences in meibomian gland morphology between children and adolescents.

METHODS

Sixty-nine patients were included in this study and divided into two groups: children (n = 31; age range: 3 to 11 years) and adolescents (n = 39; age range: 12 to 18 years). Images of meibomian glands were obtained by infrared meibography and analyzed using ImageJ software (developed by the National Institutes of Health; available at http://rsb.info.nih.gov/ij/download.html). Meibomian gland loss, the number of meibomian gland ducts, the relative width of the meibomian gland ducts, and the percent area of the meibomian gland acini were compared between the two groups.

RESULTS

Meibomian gland loss was found in both groups, but the meiboscore was not significantly different between the two groups (0.35 ± 0.6 vs 0.41 ± 0.8, t = -0.314, P > .05). The number of meibomian gland ducts (25.85 ± 3.25 vs 23.23 ± 3.06, t = -3.437, P < .05), relative width of the meibomian gland ducts (69.62% ± 5% vs 66.1% ± 7%, t = -2.454, P < .05), and percent area of the meibomian gland acini (57.7% ± 4% vs 55.5% ± 4%, t = 2.571, P < .05) in the upper eyelid were significantly greater in adolescents than in children. However, no significant differences were found in the lower eyelid between the two groups.

CONCLUSIONS

Meibography is useful for the assessment of ocular surface conditions in children and adolescents. Meibomian gland loss occurs in both children and adolescents. The meibomian glands of the upper eyelid exhibit more morphological changes in adolescents than in children. [J Pediatr Ophthalmol Strabismus. 2017;54(2):78-83.].

Influence of hyperprolactinemia on collagen fibers in the lacrimal gland of female mice

OBJECTIVE

To quantify the collagen fibers in the lacrimal gland of female mice with hyperprolactinemia.

METHODS

Forty adult female mice were randomly divided into two groups with 20 animals each: nonpregnant control (CTR1, control group, 0.2 mL of saline solution) and nonpregnant experimental (HPRL1, experimental group, 200 µg/day metoclopramide). Treatments lasted for 50 consecutive days. On day 50, 10 females from each group (control and experimental) were euthanized in the proestrus phase; then, the blood was collected and the lacrimal glands were removed. Thereafter, the remaining females were placed with the mates and continued to receive treatment with saline solution or metoclopramide. On the 6th post-coital day, 10 pregnant females from the control group (CTR2) and 10 pregnant females from the experimental group (HPRL2) were euthanized, after which blood was collected and the lacrimal glands removed. The lacrimal glands were processed for morphological analyses and collagen quantification, and prolactin and sex steroid levels were measured in the blood samples. Data were statistically analyzed using an unpaired Student t test (p<0.05).

RESULTS

Morphological analysis revealed greater structural tissue disorganization of the lacrimal glands in the metoclopramide-treated groups. The total collagen content was significantly higher in the HPRL1 group than in the CTR1 group (p<0.05), whereas the difference between the CTR2 and HPRL2 groups was not significant.

CONCLUSION

Our data suggest an impairment in the functioning of the lacrimal gland as a consequence of increased prolactin levels and decreased serum levels of estrogen and progesterone.

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.

Patients with blepharitis are at elevated risk of anxiety and depression

Purpose

Population-based cohort study on the risk of anxiety and depression in patients with blepharitis is limited. This study evaluated whether blepharitis patients are at a higher risk of anxiety and depression.

Design

A retrospective cohort study.

Methods

We used the universal insurance claims data from 1997 to 2010 in Taiwan to identify annually patients with newly diagnosed blepharitis (N = 9764) and without the disease (N = 39056). Incidences, rate ratios (IRR) and hazard ratios (HR) of anxiety and depression were measured for both cohorts by baseline demographic characteristics and comorbidities until the end of 2010.

Results

Compared with the non-blepharitis cohort, the blepharitis cohort had higher incidence of anxiety (15.9 vs. 9.5 per 1000 person-years), with an adjusted HR of 1.58 (95% confidence interval (CI) = 1.46–1.70). The incidence of depression was also higher in the blepharitis cohort (7.66 vs. 5.05 per 1000 person-years), with an adjusted HR of 1.42 (95% CI = 1.28–1.58). The blepharitis cohort to the non-blepharitis cohort IRR decreased from 1.73 in the first quartile to 1.32 in the 4^th quartile for anxiety, and from 1.67 to 1.29 for depression.

Conclusions

Patients with blepharitis are at elevated risks of anxiety and depression. The risk is higher in earlier period after the diagnosis of blepharitis, and declines by time, but remains significantly higher for those with blepharitis than those without blepharitis.

Changes in tear film, corneal topography, and refractive status in premenopausal women during menstrual cycle

PURPOSE

To investigate the changes in a questionnaire based subjective symptomatology, tear film break-up time, tear volume, corneal topography, and refractive status in premenopausal women during menstrual cycle.

METHODS

Seventeen premenopausal females and 15 healthy males were enrolled in this prospective study. After routine ophthalmologic examination, an ocular surface disease index questionnaire was administered, tear film break-up time (TBUT), and Schirmer I tests were performed. Keratometry readings and refractive status were also obtained. All examinations were repeated at day 21, day 12 and day 2.

RESULTS

OSDI score in day 21 was significantly lower than that in day 12 (p=0.004) and day 2 (p=0.01) in the female patients; however, no significant change was found in the male subjects (p>0.05). No statistically significant difference was found in TBUT and Schirmer I tests, keratometry, and refraction results in both of the female and male subjects at all of the test points (p>0.05). There was a significant correlation between OSDI score and TBUT (p=0.02, p=0.03, respectively), and Schirmer I test at day 12 (p=0.004, p=0.008, respectively). A significant negative correlation was found between oestrogen level and horizontal keratometry values at day 21 (r=-0.5, p=0.03; r=-0.4, p=0.04, respectively) for the right and left eyes in the female subjects.

CONCLUSION

Our study confirms that fluctuations in the blood levels of oestrogen produce alterations in ocular surface equilibrium during the menstrual cycle and consequently affect the subjective dry eye symptoms in female patients. However, no ocular surface parameter changes were observed.

Tear osmolarity and dry eye symptoms in women using oral contraception and contact lenses

PURPOSE

The aim of this study was to examine the relationship among oral contraceptive pill (OCP) use, contact lens wear, and dry eye signs and symptoms in healthy young women.

METHODS

Fifty-two women using OCPs and 45 women not using any form of hormonal contraception were enrolled. Medical, menstrual, and contact lens histories were obtained and dry eye symptoms assessed using the Ocular Surface Disease Index (OSDI) and Symptom Assessment iN Dry Eye (SANDE) questionnaires. Tear osmolarity testing was performed using the TearLab Osmolarity System.

RESULTS

The mean age of all subjects was 26.0 ± 3.7 years. There were no significant differences in any of the measurements between the follicular and luteal phases. Although SANDE scores were significantly higher in subjects with OCP and recent contact lens use (P < 0.01), there were no significant differences in OSDI and tear osmolarity among the same subject groups. Subjects who reported both OCP and recent contact lens use had significantly higher OSDI and SANDE scores (P = 0.015 and P < 0.001, respectively).

CONCLUSIONS

There were no differences between the phases of the menstrual cycle. Tear osmolarity was not affected by OCP or contact lens use in young women. However, the combination of OCP use and contact lens wear may increase the severity of dry eye symptoms.

Meibography: A review of techniques and technologies

Meibomian glands play a significant role in tear production by contributing lipids to the superficial tear film.(1) Dysfunction of the meibomian glands destabilizes tears resulting in evaporative dry eye.(2,3) Historically, the meibomian glands were assessed in an ex vivo fashion through histologic studies. However, innovations in ocular imaging have advanced significantly in recent decades to include meibography. Meibography is an imaging study developed 35 years ago exclusively for the purpose of observing the morphology of meibomian glands in vivo.(4,5) In this review of meibography, we briefly describe the etiology of meibomian gland dysfunction and then discuss various meibography techniques, technologies, and methods of image analysis. We close with a review of the literature, crediting various studies for the significant contributions made toward our current understanding of the meibomian glands.

Objective image analysis of the meibomian gland area

Aims

To evaluate objectively the meibomian gland area using newly developed software for non-invasive meibography.

Methods

Eighty eyelids of 42 patients without meibomian gland loss (meiboscore=0), 105 eyelids of 57 patients with loss of less than one-third total meibomian gland area (meiboscore=1), 13 eyelids of 11 patients with between one-third and two-thirds loss of meibomian gland area (meiboscore=2) and 20 eyelids of 14 patients with two-thirds loss of meibomian gland area (meiboscore=3) were studied. Lid borders were automatically determined. The software evaluated the distribution of the luminance and, by enhancing the contrast and reducing image noise, the meibomian gland area was automatically discriminated. The software calculated the ratio of the total meibomian gland area relative to the total analysis area in all subjects. Repeatability of the software was also evaluated.

Results

The mean ratio of the meibomian gland area to the total analysis area in the upper/lower eyelids was 51.9±5.7%/54.7±5.4% in subjects with a meiboscore of 0, 47.7±6.0%/51.5±5.4% in those with a meiboscore of 1, 32.0±4.4%/37.2±3.5% in those with a meiboscore of 2 and 16.7±6.4%/19.5±5.8% in subjects with a meiboscore of 3.

Conclusions

The meibomian gland area was objectively evaluated using the developed software. This system could be useful for objectively evaluating the effect of treatment on meibomian gland dysfunction.

Dry eye syndrome in aromatase inhibitor users

BACKGROUND

Aromatase inhibitors are frequently used as an adjuvant therapy in the treatment of breast cancer. We observed that several patients taking aromatase inhibitors presented with severe dry eye symptoms, and we investigated whether there is a relationship between aromatase inhibitors and dry eyes in these patients.

DESIGN

Retrospective chart review.

PARTICIPANTS

Forty-one women.

METHODS

A computerized search of health records was performed to identify patients using anastrazole, letrozole and exemestane seen by the Cornea Service from August 2008 to March 2011. The results were compared with age-matched controls.

MAIN OUTCOME MEASURES

Ocular surface changes among aromatase inhibitors users.

RESULTS

Of the 41 women, 39 were Caucasians. Thirty-nine patients had breast cancer (95%), one patient had ovarian cancer (2.5%) and one had an unknown primary cancer. Mean age was 68 ± 11.3 years (range 47-95). Most common presenting symptoms were blurred vision in 28 (68%) patients, irritation/foreign body sensation in 12 (29%) patients, redness in 9 (22%) patients, tearing in 6 (22%) patients and photosensitivity in 2 (5%) patients. Mean Schirmer's test measurement was 11 ± 5.8 mm (range 0.5-20 mm). Blepharitis was noted in 68 of 82 eyes (73%), decreased or poor tear function in 24 eyes (29%), conjunctival injection in 18 eyes (22%) and superficial punctate keratitis in 12 eyes (29%). Among an age-matched population (45-95 years), dry eye syndrome was found in only 9.5% of patients.

CONCLUSIONS

Because the prevalence of ocular surface disease signs and symptoms appears to be higher in study group than control patients, aromatase inhibitors might be a contributing factor to the dry eye symptoms.

The lid wiper and muco-cutaneous junction anatomy of the human eyelid margins: an in vivo confocal and histological study

The inner border of the eyelid margin is critically important for ocular surface integrity because it guarantees the thin spread of the tear film. Its exact morphology in the human is still insufficiently known. The histology in serial sections of upper and lower lid margins in whole-mount specimens from 10 human body donors was compared to in vivo confocal microscopy of eight eyes with a Heidelberg retina-tomograph (HRT II) and attached Rostock cornea module. Behind the posterior margin of the Meibomian orifices, the cornified epidermis stopped abruptly and was replaced by a continuous layer of para-keratinized (pk) cells followed by discontinuous pk cells. The pk cells covered the muco-cutaneous junction (MCJ), the surface of which corresponded to the line of Marx (0.2-0.3 mm wide). Then a stratified epithelium with a conjunctival structure of cuboidal cells, some pk cells, and goblet cells formed an epithelial elevation of typically about 100 μm initial thickness (lid wiper). This continued for 0.3-1.5 mm and formed a slope. The MCJ and lid wiper extended all along the lid margin from nasal to temporal positions in the upper and lower lids. Details of the epithelium and connective tissue were also detectable using the Rostock cornea module. The human inner lid border has distinct zones. Due to its location and morphology, the epithelial lip of the lid wiper appears a suitable structure to spread the tear film and is distinct from the MCJ/line of Marx. Better knowledge of the lid margin appears important for understanding dry eye disease and its morphology can be analysed clinically by in vivo confocal microscopy.

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.

Nonobvious obstructive meibomian gland dysfunction

This review presents the rationale and supporting data for a recent paradigm shift in our understanding of meibomian gland dysfunction (MGD). The historical understanding of MGD has been that of an infectious hypersecretory disorder with obvious signs of inflammation, hypersecretion, and purulent excreta. The current understanding of MGD now includes the polar concept of a less obvious or nonobvious type of hyposecretory obstructive MGD, where inflammation and other signs of pathology may be absent unless special examination techniques are employed. A new term, nonobvious obstructive MGD (NOMGD), is used to describe what may be the most common form of obstructive MGD. Obstructive MGD is an area of growing importance because obstructive MGD is now recognized to be the most common cause of evaporative dry eye, and because NOMGD seems to be the precursor to obvious obstructive MGD, it is also an important area to understand. The prevalence of NOMGD seems to be very high but currently significantly underdiagnosed. This review presents the relevant anatomy and physiology, concepts of obstructive MGD, the usual absence of inflammation in obstructive MGD, nomenclature and classification of obstructive and NOMGD, clinical diagnosis of NOMGD emphasizing the necessity for diagnostic expression, the use of a new instrument for diagnostic expression providing a standardized method of assessing meibomian gland functionality, the complementary roles of the aqueous and lipid layers, and the specific treatment of NOMGD, emphasizing that the success of treatment of all forms of obstructive MGD is dependent on the relief of the obstruction.

[Sex hormones and dry eye]

Among ophthalmic diseases dry eye in its various forms, represents an entity with one of the highest prevalences and at the same time the lowest chance for causal therapy. Since some years there is growing evidence that sex hormones play a key role in the formation and course of the disease and thus provide potentially promising approaches for therapy. The objective of this article is to briefly outline current scientific knowledge on the relationship between androgens, estrogens,and progesterones on the one hand and the lacrimal gland and Meibomian glands respectively.

The Meibomian puzzle: combining pieces together

The purpose of this review was to summarize the available information on lipidomic analysis of human meibum and tear film, and critically evaluate the pertinent past and present analytical procedures and results obtained in various laboratories. Human meibum was shown to be a very complex mixture of lipids of various classes. For decades, their exact structures have remained elusive. Because of the limitations of the then-current techniques, most of the complex lipids that constitute meibum could not be analyzed as whole molecules and required prior hydrolysis and/or transesterification of the entire lipid pool. These procedures effectively made it very difficult, and often impossible, to reconstruct the complete structures of the original intact compounds, which prompted us to call this The Meibomian Puzzle. Modern techniques such as high-performance liquid chromatography in combination with mass spectrometry help in solving this puzzle by allowing a researcher to detect and analyze intact molecules of complex lipid compounds, even if present in extremely low concentrations. This current de-facto standard procedure in lipidomic analysis of natural lipids and their mixtures is compared with other experimental techniques such as nuclear magnetic resonance spectroscopy, infrared spectroscopy, gas chromatography, and thin layer chromatography, among the others. The results obtained by older techniques, and their limitations and deficiencies are discussed. It appears that some of the earlier findings did not withstand a scrupulous re-evaluation and need to be modified and/or corrected. The most intriguing development is the virtual absence in meibum of typical phospholipids - an important group of amphiphilic compounds whose role in the human tear film was thought to be to stabilize the entire tear film structure. Instead, another group of previously unidentified compounds, very long chain (O-acyl)-omega-hydroxy fatty acids, appears to be a stabilizing factor which might be related to tear film stability and deterioration. Thus, these compounds may become an important target in biochemistry and (patho)physiology of ocular surface and dry eye research.

Age-related changes in the meibomian gland

The purpose of this study was to characterize the age-related changes of the mouse meibomian gland. Eyelids from adult C57Bl/6 mice at 2, 6, 12 and 24 months of age were stained with specific antibodies against peroxisome proliferator activated receptor gamma (PPARgamma) to identify differentiating meibocytes, Oil Red O (ORO) to identify lipid, Ki67 nuclear antigen to identify cycling cells, B-lymphocyte-induced maturation protein-1 (Blimp1) to identify potential stem cells and CD45 to identify immune cells. Meibomian glands from younger mice (2 and 6 months) showed cytoplasmic and perinuclear staining with anti-PPARgamma antibodies with abundant ORO staining of small, intracellular lipid droplets. Meibomian glands from older mice (12 and 24 months) showed only nuclear PPARgamma localization with less ORO staining and significantly reduced acinar tissue (p < 0.04). Acini of older mice also showed significantly reduced (p < 0.004) numbers of Ki67 stained nuclei. While Blimp1 appeared to diffusely stain the superficial ductal epithelium, isolated cells were occasionally stained within the meibomian gland duct and acini of older mice that also stained with CD45 antibodies, suggesting the presence of infiltrating plasmacytoid cells. These findings suggest that there is altered PPARgamma receptor signaling in older mice that may underlie changes in cell cycle entry/proliferation, lipid synthesis and gland atrophy during aging. These results are consistent with the hypothesis that mouse meibomian glands undergo age-related changes similar to those identified in humans and may be used as a model for age-related meibomian gland dysfunction.

Prevalence of dry eye disease among US men: estimates from the Physicians' Health Studies

OBJECTIVE

To estimate the prevalence and risk factors for dry eye disease (DED) among US men.

METHODS

Cross-sectional prevalence survey among male participants 50 years and older in the Physicians' Health Studies I (N = 18,596) and II (N = 6848). We defined DED as the presence of clinically diagnosed dry eye or severe symptoms (both dryness and irritation constantly or often). We calculated the age-standardized prevalence of DED adjusted to the age distribution of US men in 2004 and projected estimates forward to 2030. We compared DED prevalence with a similar cohort of women and examined associations with possible risk factors.

RESULTS

The prevalence of DED increased with age, from 3.90% among men aged 50 to 54 years to 7.67% among men 80 years and older (P for trend <.001). High blood pressure (odds ratio, 1.28; 95% confidence interval, 1.12-1.45) and benign prostatic hyperplasia (odds ratio, 1.26; 95% confidence interval, 1.09-1.44) were associated with a higher risk of DED. Use of antidepressants, antihypertensives, and medications to treat benign prostatic hyperplasia were also associated with increased risk of DED. The age-standardized prevalence of DED was 4.34%, or 1.68 million men 50 years and older, and is expected to affect more than 2.79 million US men by 2030.

CONCLUSIONS

Dry eye disease is prevalent and increases with age, hypertension, benign prostatic hyperplasia, and antidepressant use.

Human tear film and meibum. Very long chain wax esters and (O-acyl)-omega-hydroxy fatty acids of meibum

Human meibum was targetly analyzed for the presence of intact wax esters (WEs) and related compounds by means of reverse-phase HPLC in combination with ion trap mass spectrometry. The major detected WEs were based on C(18:n) (n = 1-4) unsaturated FAs ranking in the following order of abundance: C(18:1)>C(18:2)>C(18:3)>C(18:4). The major fatty alcohols (FAls) found in WE were of saturated nature and varied from C(18:0) to C(28:0). The three most abundant species were C(18:1)-FA esters of C(24:0), C(25:0), and C(26:0)-FAl. Typically, a major compound based on C(18:1)-FA and a saturated FAl was accompanied by a few related compounds based on a C(18:2), C(18:3), and C(18:4)-FA. Contrary to previous reports, no epoxy-WEs or epoxy-FAs were detected in fresh and 1-year-old meibum samples. More than 20 (O-acyl)-omega-hydroxy-FAs (OAHFAs) were observed. The main detected OAHFAs were based on very long-chain omega-hydroxy-FA (C(30:1), C(32:1), and C(34:1)) acylated through their omega-hydroxyls by a C(18:1)-FA. Due to their amphiphilic anionogenic nature, OAHFAs may be responsible for stabilization of the tear film lipid layer by creating an interface between the vast pool of strictly nonpolar lipids of meibum (WEs, cholesteryl esters, etc.) and the aqueous subphase beneath it, a role previously attributed to phospholipids.

Inner eyelid surface temperature as a function of warm compress methodology

PURPOSE

To (1) determine an optimal method of warm compress (WC) application to maximize heating meibomian glands in minimal time, (2) determine the maximum inner eyelid temperature achievable during 30 min of routine WC application, (3) examine the cooling curve for 10 min after WCs have been discontinued.

METHODS

Subjects were randomly assigned to one of three WC methodologies. Group A (GrA), (n = 10): 15 min WC application without reheating. GrB, (n = 10): 30 min WC application with reheating every 2 min. GrC, (n = 12): 30 min WC application optimizing contact with the lower lid and reheating every 2 min. WCs were heated to 45 +/- 0.5 degrees C. Outer and inner lower eyelid surface temperatures were measured at baseline and regular intervals.

RESULTS

GrA: the maximum outer and inner lower eyelid surface temperatures = 41.2 +/- 0.3 degrees C at 1 min and 38.8 +/- 0.2 degrees C after 4 min, respectively. GrB: the maximum outer upper eyelid temperature, 43.3 +/- 0.5 degrees C, was reached after 6 min while it required 30 min to reach the maximum inner lower eyelid temperature, 40.4 +/- 0.3 degrees C. GrC: it required 4 min to reach the maximum outer lower eyelid temperature, 42.2 +/- 0.4 degrees C, while it required 20 min to reach the maximum inner lower eyelid temperature, 40.8 +/- 0.3 degrees C.

CONCLUSIONS

To optimize WC efficiency, patients should (1) heat the WC to approximately 45 degrees C, (2) optimize contact between the WC and outer eyelid surfaces, (3) reheat the WC frequently and have a replacement heated WC on hand for exchange, and (4) perform the activity for at least 4 min in order to achieve an inner lower eyelid temperature > or = 40 degrees C. Longer therapy may be necessary for more severe obstructions. These data suggest that precise, customized, labor-intensive WC procedure is necessary to optimize treating meibomian gland dysfunction and obstruction using WCs.

Association between meibomian gland changes and aging, sex, or tear function

PURPOSE

To study changes in the lid margin and meibomian glands and their association with aging, sex, and tear function.

METHODS

We examined 354 eyes in 177 subjects (76 men and 101 women; 21-93 years; mean age, 63.0 +/- 14.3 years) with no ocular symptoms or ocular surface disorders. Anatomic changes in the lid margin were studied using slit-lamp biomicroscopy. Meibomian gland function and morphology were evaluated on the basis of meibum expression and meibography, respectively. Tear function and ocular surface epithelium were assessed with the Schirmer test, by tear film break-up time, and with a fluorescein staining test.

RESULTS

Eyes with abnormal lid margin anatomy, hyposecretion of meibum, and meibomian gland dropout were seen in 26 (7.3%), 46 (12.4%), and 68 eyes (18.6%), respectively, with a significant association between each finding and aging (P = <0.0001, 0.0498, and <0.0001, respectively). In patients < or =69 years of age, no significant association was found between meibomian gland-related findings and sex. However, a high incidence of abnormal lid margin and gland dropout was noted in men > or =70 years of age compared with women. No significant association was found between changes in the lid margin and meibomian glands and tear function in patients > or =40 years of age.

CONCLUSION

Among symptom-free subjects, we found that changes in the lid margin and meibomian glands were closely related to aging. Among elderly subjects, changes in the anatomic lid margin and meibomian gland morphology were observed more frequently in men than in women. Tear function showed no association with either changes in the lid margin or function of the meibomian glands.

Impact of dry eye syndrome on vision-related quality of life

PURPOSE

To evaluate the impact of dry eye syndrome (DES) on vision-associated quality of life.

DESIGN

Cross-sectional study.

METHODS

We identified 450 participants in the Women's Health Study (WHS) and 240 participants in the Physicians' Health Study (PHS) and sent a supplementary questionnaire asking how much their everyday activities were limited by symptoms of dry eye and to what degree problems with their eyes limited them in reading, driving, working at the computer, their professional activity, and watching television. By design, one-third of study subjects had clinically diagnosed DES or severe symptoms and two-thirds did not. We used logistic regression to examine relationships of DES with reported problems with everyday activities in each cohort and pooled estimates using meta-analysis methods.

RESULTS

Of the participants invited, 85% completed the supplementary questionnaire, including 135 WHS and 55 PHS participants with DES, and 250 WHS and 149 PHS participants without DES. Controlling for age, diabetes, hypertension, and other factors, those with DES were more likely to report problems with reading ([odds ratio] OR = 3.64, 95% [confidence interval] CI 2.45 to 5.40, P < .0001); carrying out professional work (OR = 3.49, 95% CI 1.72 to 7.09, P= 0.001); using a computer (OR = 3.37, 95% CI 2.11 to 5.38, P < .0001); watching television (OR = 2.84, 95% CI 1.05 to 7.74, P = .04); driving during the day (OR = 2.80, 95% CI 1.58 to 4.96, P < .0001); and driving at night (OR = 2.20, 95% CI 1.48 to 3.28, P < .0001).

CONCLUSIONS

DES is associated with a measurable adverse impact on several common and important tasks of daily living, further implicating this condition as an important public health problem deserving increased attention and resources.

Aktuelle Therapie des trockenen Auges

The therapy of dry eye disease as a chronic problem necessitates a long-term therapeutic association between patient and ophthalmologist. The aim of therapy is to relieve symptoms and improve vision as far as possible with an acceptable level of effort on the part of the patient. Therapy of dry eye follows a staged concept including tear replacement, serum eye drops, punctum plugs, novel anti-inflammatory drugs (cyclosporin A), and surgical procedures. Interdisciplinary care, especially of patients with autoimmune disease, is recommended and is best provided in a specialized dry eye outpatient clinic with quality control.

Tear film tests in Parkinson's disease patients

OBJECTIVE

Parkinson's disease (PD) has both motor and nonmotor features. Parkinson's disease patients are prone to dry eye due to both autonomic dysfunction and motor symptoms affecting blinking. This study was conducted to investigate the changes in tear functions in PD patients.

DESIGN

Nonrandomized, prospective, clinical study.

PARTICIPANTS

Fifty-six eyes of 56 consecutive patients with PD were studied. Thirty-six eyes of age-matched non-PD patients without pathology affecting tear tests were examined as control subjects.

INTERVENTION

Modified Hoehn-Yahr (H-Y) scale, blink rate (BR), and tear tests were examined.

MAIN OUTCOME MEASURES

Modified H-Y scale, BR, dry eye assessment questionnaire, meibomian gland evaluation, tear meniscus height, tear breakup time, fluorescein stain, rose bengal stain, Schirmer's test, and phenol red thread test.

RESULTS

Overall tear function abnormalities were significantly more common in PD patients (P = 0.001, Mann-Whitney U test). Each test was found to be significantly disturbed in PD patients relative to controls (P<0.05, Mann-Whitney U test). Each PD patient had at least 1 abnormal test. Overall tear function abnormalities as assessed by the total abnormal test count correlated with the H-Y score (P<0.001, Spearman rho correlation). Parkinson's disease patients' mean BR (12.7+/-7.42 per minute) was significantly less than the controls' (21.8+/-7.37) (P<0.01, Student's t test). The abnormality in each tear test, except those for meibomian gland function and tear meniscus height, was significantly related to the H-Y scores (P<0.05, chi2 linear-by-linear association).

CONCLUSION

The results of this study indicate that PD is associated with disturbances in tear function. With the exception of meibomian gland disease and tear meniscus height, the tests were found to have a linear association with the H-Y scale, which may be attributed to associated dysfunctions of PD.

Differences in keratoconus as a function of gender

PURPOSE

To characterize gender differences in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study.

DESIGN

Observational, longitudinal study.

METHODS

A total of 1209 subjects at 16 clinics. For eye-specific categorical variables, the number of eyes per subject with the characteristic was counted. For eye-specific continuous variables, the mean of both eyes was calculated. Multivariate linear (for continuous outcomes) and logistic (for categorical outcomes) regression models were created for each baseline characteristic with statistically significant (P < or = .05) differences between men and women. Age, race, education, and corneal curvature were covariates.

RESULTS

The women were older, more likely to report a family history of keratoconus, more likely to be nonwhite, and less likely to complete college than men. Vogt's striae and monocular and binocular high-contrast entrance acuity were the only visual characteristics that varied between men and women in the multivariate model. Women were more likely than men to report ocular symptoms of dryness and complaints based upon a composite score of ocular symptoms. Women reported more hours per day of near work and were less likely to report the ability to wear contact lenses for enough hours to permit reading at home in the evening. Women reported more visits to their eye care practitioner during the previous 12 months. NEI-VFQ results revealed differences in self-reported difficulty with distance activities and driving.

CONCLUSIONS

Gender differences exist in patient history, vision, and ocular symptoms in keratoconus patients.

Age-dependent alterations in mouse exorbital lacrimal gland structure, innervation and secretory response

Several studies investigated the effect of aging on rat and human lacrimal gland physiology. However, in most of these studies, only two age groups were investigated. Furthermore, those studies did not correlate the age-related histological changes that occur in the lacrimal gland to the functional changes (nerve activity and protein secretion) that might occur with aging. Thus, the purpose of the present study was to investigate the effect of aging on lacrimal gland structure, innervation and function using BALB/c mice at different ages. Exorbital lacrimal glands were removed from 3, 8, 12, 24, and 32-month-old, male BALB/c mice, fixed, embedded and processed for histology and immunohistochemistry. Sections were stained with hematoxylin and eosin to determine morphological changes and lymphocytic infiltration; giemsa to identify mast cells; and Kinyoun's carbol fucsin solution to indicate lipofuscin-like inclusions. Parasympathetic and sympathetic nerves were identified by immunofluorescence techniques. To measure acetylcholine release and protein secretion, lacrimal gland pieces were incubated in Krebs Ringer buffer containing 5 mM KCl (control), 75 mM KCl (depolarizing buffer which activates nerves), carbachol (a cholinergic agonist, 10(-4) M), or phenylephrine (an alpha1-adrenergic agonist, 10(-4) M) for 20 min. The media were collected and analysed for acetylcholine and peroxidase using a spectrofluorometric assay. KCl-, carbachol- and phenylephrine-stimulated peroxidase secretion decreased in lacrimal glands from 8, 12, and 24-month-old mice when compared to 3-month-old animals. Both the density and distribution of parasympathetic and sympathetic nerves surrounding the acini decreased with increasing age. Acetylcholine release from lacrimal gland nerves decreased in 24-month-old mice compared to 3- and 12-month-old animals. Similarly, progressive morphological changes, including increased numbers of lipofuscin-like inclusions, mast cells and lymphocytic infiltration occurred in an age-dependent manner. We conclude that structural alterations of mouse lacrimal gland, including increased accumulation of lipofuscin-like inclusions, chronic inflammation and functional alterations including decreased acetylcholine release and protein secretion occurred with aging.