Prevalence of dry eye and Meibomian gland dysfunction in Central and South America: a systematic review and meta-analysis

BACKGROUND

Dry eye is one of the most common ophthalmic conditions and can significantly impact quality of life. Meibomian gland dysfunction (MGD) is a major cause of evaporative dry eye. We sought to conduct a systematic review and meta-analysis to estimate the prevalence and incidence of dry eye and MGD in Central and South America and to identify factors associated with disease burden.

METHODS

Data sources Ovid MEDLINE and Embase.

STUDY SELECTION

A search conducted on August 16, 2021, identified studies published between January 1, 2010, and August 16, 2021, with no restrictions regarding participant age or language of publication. Case reports, case series, case-control studies, and interventional studies were excluded.

DATA EXTRACTION AND SYNTHESIS

The review was based on a protocol registered on PROSPERO (CRD42021256934). Risk of bias was assessed in duplicate using a risk of bias tool designed for the purposes of descriptive epidemiological studies. Data were extracted by one investigator and verified by another for accuracy. Prevalence of dry eye and MGD were grouped based on study participant characteristics.

MAIN OUTCOMES AND MEASURES

Prevalence and incidence of dry eye and MGD in Central and South America. Summary estimates from meta-analysis with 95% confidence intervals (CI).

RESULTS

Fourteen studies (11,594 total participants) were included. The population prevalence of dry eye was 13% (95% CI, 12%-14%) in Brazil and 41% (95% CI, 39%-44%) in Mexico based on one study each. Meta-analyses suggested that dry eye prevalence was 70% among indoor workers (95% CI, 56%-80%; I2, 82%; 3 studies), 71% among students (95% CI, 65%-77%; I2, 92%; 3 studies), and 83% in general ophthalmology clinics (95% CI, 77%-88%; I2, 88%; 2 studies). MGD prevalence ranged from 23% among indoor workers (95% CI, 16%-31%; 1 study) to 68% in general ophthalmology clinics (95% CI, 62%-72%; 1 study). No studies reported incidence of dry eye or MGD.

CONCLUSIONS

This systematic review and meta-analysis demonstrated considerable variation in the published prevalence of dry eye and MGD among the general population and subpopulations in Central and South America. Local and subpopulation estimates of dry eye disease burden may be valuable to assist needs assessments and implementation of measures to mitigate the condition.

Determining the effect of climate and profession on dry eye disease: A prevalence study among young males in north, north-west and central India

Background

Ocular tear film and the ocular surface together represent a dynamic playground of various protective factors against environmental influencers. Surrounding environment and geoclimatic milieu are the pertinent and continuous influencing factors. Prevalence study of Dry eye disease (DED) in various climatic conditions and professions provides an insight into this peculiar aspect of DED and human geography.

Methods

This was a hospital based, cross-sectional, comparative, analytical observational study. 1840 young soldiers between 25 and 45 years of age were studied. Divided in five climate groups based on Köppen-Geiger climate classification system the subjects were sub-grouped into professions exposed to known aggravating environmental factors. The ocular surface was examined for signs and symptoms of DED and its prevalence and risk ratio for different climates and professions were calculated.

Results

Highest prevalence of DED was found in cold desert climate and among visual display unit (VDU) users. Least prevalence was seen in highland type of climate and among people involved in professional exposed to high temperature. Prevalence of DED based upon the signs and ocular surface disease index (OSDI) was calculated and stratified with risk ratio for climatic conditions and professions.

Conclusion

Different climatic conditions and professions had different prevalence of signs, symptoms of OSD and DED which indicated its influence on prevalence of the disease.

Dry eye disease and blinking behaviors: A narrative review of methodologies for measuring blink dynamics and inducing blink response

Dry eye disease (DED) is a leading cause of ophthalmology clinical encounters with prevalence ranging from 8.7% to 64% in various populations. Blinking is an endogenous process to refresh the tear film, clear debris and maintain quality vision. Altered blinking behavior is a common feature of DED and is implicated in the pathology of the disease. However, lack of a comprehensive review on the relationship between altered blinking behavior and DED is notable in the literature. Blinking behavior may be an effect of DED due to an unstable tear film sensitizing a motor response or be its cause due to destabilization of the tear film in conditions such as benign essential blepharospasm. In this comprehensive review, we summarize the current models and theories of tear film dynamics and blinking behavior to better understand their connection to DED and introduce contemporary technologies and measurement tools used in the evaluation and induction of blinking behavior. We also describe future directions of research to better understand the relationship between DED and blinking and explore therapies that address the abnormal blinking component of DED.

Oral azithromycin and oral doxycycline for the treatment of Meibomian gland dysfunction: A 9-month comparative case series

Purpose

To compare the efficacy and safety profile of oral azithromycin with that of doxycycline over 9 months in patients experiencing failure with conservative and topical treatment for Meibomian gland dysfunction (MGD), to assess recurrence of MGD, and to determine the number of treatments required.

Methods

This is a randomized controlled trial with a cross-over design at a tertiary care center. In all, 115 consecutive patients underwent a complete ophthalmological examination before being randomly assigned to oral treatment with doxycline (4 g for 30 days) or azithromycin (1.25 g for 5 days). Patients were evaluated at 3, 6, and 9 months. Therapy was switched or conservative management maintained according to signs and symptoms.

Results

In the azithromycin group, 83.25% of the patients were stable after one treatment, 16.5% needed a further one or two treatments (some had previously been switched to doxycycline), and 5.77% did not improve despite treatment. In the doxycycline group, 33.79% of patients were stable after one treatment, 66.21% needed a further one or two treatments (some had previously switched to azithromycin), and 29.41% did not improve despite treatment (P < 0.05). Minimal gastrointestinal adverse effects (nausea, diarrhea, abdominal cramp, and decreased appetite) were reported, mostly unchanged at the follow-up visits. At the first visit, more adverse effects were reported in the doxycycline group (14/51, 24%) than in the azithromycin group (3/52, 6%; P < 0.005).

Conclusion

Both antibiotics were effective and safe for treating patients with persistent MGD, although azithromycin was superior when the reduced dose and the shorter course of therapy (5 days vs. 4 weeks) were taken into consideration. Given the chronic nature of the disease and the improvement in some signs with minimal adverse effects, a shorter therapy seems a safer and more logical alternative to longer regimens.

Untargeted lipidomic analysis of human tears: A new approach for quantification of O-acyl-omega hydroxy fatty acids

PURPOSE

The purpose of this work was to optimize methodology to analyze the human tear film lipids by using untargeted, direct infusion electrospray ionization-mass spectrometry (ESI-MS) to establish the analytical approach for a large-scale clinical translational study of tear film lipids in ocular surface disease, particularly associated with the O-acyl-omega hydroxy fatty acids (OAHFAs).

METHODS

Meibum and tear samples were collected from both eyes of five normal subjects without ocular disease using two different microcapillary collection tubes, glass and polytetrafluoroethylene (PTFE). An untargeted lipidomics approach was used to analyze the lipids in human tear and meibum samples using direct infusion ESI-MS in positive and negative ion modes. Direct and indirect quantification methods were evaluated.

RESULTS

The amount of OAHFAs measured in tears using these techniques was approximately 0.7-0.8% of the total lipids. More phospholipids, including phosphatidylcholine and sphingomyelin, were detected in the tear samples associated with glass microcapillaries compared to PTFE.

CONCLUSIONS

Reliable assessment of lipids in small volumes of tear film is possible using high resolution, untargeted ESI-MS in positive and negative ion modes. Using this technique, the concentration of OAHFAs can be quantified, as can the presence of other polar lipids.

Semifluorinated Alkane Eye Drops for Treatment of Dry Eye Disease Due to Meibomian Gland Disease

Purpose: Meibomian gland disease is generally accepted as the leading cause for evaporative dry eye disease (DED). In a previous study, perfluorohexyloctane, a semifluorinated alkane, has been demonstrated to significantly increase tear film breakup time and to reduce corneal fluorescein staining in patients with evaporative DED, thereby vastly reducing dry eye-related symptoms. This study was set up to evaluate perfluorohexyloctane in a larger population of patients with Meibomian gland dysfunction.

Methods: Seventy-two patients with Meibomian gland disease and associated dry eye received 1 drop of perfluorohexyloctane 4 times daily during an observational, prospective, multicenter, 6–8-week study. Clinical assessment included best-corrected visual acuity, intraocular pressure, Schirmer test I, tear film breakup time, anterior and posterior blepharitis assessment, number of expressible Meibomian glands, meibum quality and quantity, ocular surface fluorescein staining, lid margin and symptom assessment, and Ocular Surface Disease Index (OSDI^©).

Results: From the 72 patients recruited, 61 completed the trial per protocol. Nine patients did not apply the medication as recommended and 2 patients were lost to follow-up. Tear film breakup time, corneal and conjunctival fluorescein staining, number of expressible Meibomian glands, and severity of anterior and posterior blepharitis significantly improved after 6–8 weeks of perfluorohexyloctane application. In addition, symptoms improved as demonstrated by a significant decrease of OSDI-values from 37 (±13) to 26 (±16).

Conclusions: In concordance with previous findings, 6–8 weeks of topical application of perfluorohexyloctane significantly improves clinical signs of Meibomian gland disease and associated mild to moderate DED.

Reduced ocular surface disease index (OSDI) scores in patients with isotretinoin treatment

To evaluate the changes in ocular surface and functions of tear-film in patients treated with systemic isotretinoin, to assess diagnostic performance of ocular surface disease index (OSDI) test in the dry eye conditions in association with the use of isotretinoin, and to determine the correlation between all tear-film function tests, OSDI and the dose and duration of isotretinoin administration. One hundred and twenty eyes of 60 subjects treated with oral isotretinoin were enrolled. All patients underwent ophthalmic examination at the baseline and another examination during the course of treatment. Biomicroscopic ophthalmic examination of the meibomian glands, non-anesthetized Schirmer test, and tear film break-up time (BUT) were performed. Subjective ocular complaints were scored with an OSDI questionnaire. Average Schirmer scores were not significantly changed by isotretinoin treatment. There were significant differences in the average OSDI score, the average meibomian gland disease (MGD) grade and average BUT value of both eyes during the treatment compared with baseline values (p < 0.01). There was a statistically significant inverse correlation between MGD grade and BUT value. There was no significant correlation between BUT value, OSDI score, Schirmer score, MGD grade, the total and divided dose of isotretinoin and the duration of treatment. The follow-up time was 4.01 ± 1.3 months (range 1.5-6 months). Systemic isotretinoin treatment can cause alterations in the tear film and dry eye symptoms. The OSDI test can be used as a diagnostic test for patients receiving systemic isotretinoin treatment.

Sebaceous lipids are essential for water repulsion, protection against UVB-induced apoptosis and ocular integrity in mice

Sebocytes, which are characterized by lipid accumulation that leads to cell disruption, can be found in hair follicle-associated sebaceous glands (SGs) or in free SGs such as the Meibomian glands in the eyelids. Because genetic tools that allow targeting of sebocytes while maintaining intact epidermal lipids are lacking, the relevance of sebaceous lipids in health and disease remains poorly understood. Using Scd3, which is expressed exclusively in mature sebocytes, we established a mouse line with sebocyte-specific expression of Cre recombinase. Both RT-PCR analysis and crossing into Rosa26-lacZ reporter mice and Kras(G12D) mice confirmed Cre activity specifically in SGs, with no activity in other skin compartments. Importantly, loss of SCD3 function did not cause detectable phenotypical alterations, endorsing the usefulness of Scd3-Cre mice for further functional studies. Scd3-Cre-induced, diphtheria chain A toxin-mediated depletion of sebaceous lipids resulted in impaired water repulsion and thermoregulation, increased rates of UVB-induced epidermal apoptosis and caused a severe pathology of the ocular surface resembling Meibomian gland dysfunction. This novel mouse line will be useful for further investigating the roles of sebaceous lipids in skin and eye integrity.