Development of the 4–3–2–1 Meibum Expressibility Scale

Advances in artificial intelligence for meibomian gland evaluation: A comprehensive review

Meibomian gland dysfunction (MGD) is increasingly recognized as a critical contributor to evaporative dry eye, significantly impacting visual quality. With a global prevalence estimated at 35.8 %, it presents substantial challenges for clinicians. Conventional manual evaluation techniques for MGD face limitations characterized by inefficiencies, high subjectivity, limited big data processing capabilities, and a dearth of quantitative analytical tools. With rapidly advancing artificial intelligence (AI) techniques revolutionizing ophthalmology, studies are now leveraging sophisticated AI methodologies--including computer vision, unsupervised learning, and supervised learning--to facilitate comprehensive analyses of meibomian gland (MG) evaluations. These evaluations employ various techniques, including slit lamp examination, infrared imaging, confocal microscopy, and optical coherence tomography. This paradigm shift promises enhanced accuracy and consistency in disease evaluation and severity classification. While AI has achieved preliminary strides in meibomian gland evaluation, ongoing advancements in system development and clinical validation are imperative. We review the evolution of MG evaluation, juxtapose AI-driven methods with traditional approaches, elucidate the specific roles of diverse AI technologies, and explore their practical applications using various evaluation techniques. Moreover, we delve into critical considerations for the clinical deployment of AI technologies and envisages future prospects, providing novel insights into MG evaluation and fostering technological and clinical progress in this arena.

LipiFlow for the treatment of dry eye disease

BACKGROUND

Meibomian gland dysfunction (MGD) is the most common underlying cause of dry eye disease (DED). MGD leads to pathological alteration of the composition or quantity of meibum, or both, which subsequently results in tear evaporation and the typical signs and symptoms associated with DED. The LipiFlow Thermal Pulsation System (LipiFlow) is a medical device used to treat MGD in office; however, it is unclear if LipiFlow can outperform other DED treatments.

OBJECTIVES

To evaluate the effectiveness of LipiFlow for treating DED signs and symptoms and the safety of LipiFlow compared with sham or other available treatments for MGD in adults.

SEARCH METHODS

The Cochrane Eyes and Vision Information Specialist searched the electronic databases for randomized controlled trials. There were no restrictions on language or date of publication. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, including the Cochrane Eyes and Vision Trials Register; 2022, Issue 6), MEDLINE Ovid, Embase.com, PubMed, LILACS (Latin American and Caribbean Health Science Information database), ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) electronic databases. We also examined the reference lists of identified trials, review articles, and guidelines for information about relevant trials that may not have been identified by our search strategy. We contacted investigators regarding ongoing trials. The last database search was performed on 24 October 2022.

SELECTION CRITERIA

We included studies conducted in adults (over 18 years of age) with DED or MGD as defined by the primary trial investigators. We imposed no restrictions on race, ethnicity, or sex. We considered trials involving contact lens wearers if they were equally represented between groups.

DATA COLLECTION AND ANALYSIS

We applied standard Cochrane methodology.

MAIN RESULTS

We included 13 trials that randomized a total of 1155 participants (28 to 236 participants randomized per study). Six trials were conducted in the USA, three in China, two in Thailand, one in France, and one in Italy. Eight trials were of single-center design, while four trials were of multicenter design; one trial did not report the number of participating centers. Study characteristics The study population of the included trials was 66% female (range 48% to 80%), with an age range of 19 to 86 years. LipiFlow, used as a stand-alone intervention, was compared with basic warm compresses in five studies, thermostatic device in five studies, oral intervention in one trial, and topical dry eye medications in one trial. LipiFlow was also evaluated together with eyelid hygiene product versus eyelid hygiene products alone in one trial. Findings Five trials compared LipiFlow with a basic warm compress applied for varying durations and frequencies during the trial period; only one of these trials combined a warm compress with eyelid massage. Analyzing symptom scores by different questionnaires (Ocular Surface Disease Index [OSDI] and Standard Patient Evaluation of Eye Dryness [SPEED]) yielded conflicting evidence of a difference in symptoms between LipiFlow and basic warm compresses after four weeks. There was no evidence of a difference in meibomian gland expression, meibum quality, or tear breakup time when comparing LipiFlow with basic warm compresses. Another five trials compared LipiFlow with thermostatic devices. Analysis of symptom scores at four weeks showed that thermostatic devices had reduced OSDI scores by a mean difference (MD) of 4.59 (95% confidence interval [CI] 1.23 to 7.95; I2 = 0, P = 0.007; 553 participants; very low certainty evidence) as compared with LipiFlow. When we compared LipiFlow plus eyelid hygiene with eyelid hygiene alone, there was no evidence of difference in signs or symptoms at any time point evaluated. Only one trial compared LipiFlow with a topical DED medication (lifitegrast 5%). The single-trial estimate suggested that 5% lifitegrast may increase meibomian gland expression scores compared with LipiFlow at day 42 (MD -1.21, 95% CI -2.37 to -0.05; 50 participants; low certainty evidence) by using a meibomian gland expression scale of 0 to 8. One trial compared LipiFlow with an oral intervention (doxycycline), finding that LipiFlow may result in significantly better SPEED scores than doxycycline at three months (MD -4.00, 95% CI -7.33 to -0.67; 24 participants; very low certainty evidence). No other significant differences in signs or symptoms were found between LipiFlow and doxycycline at three months. We did not find any other statistically significant differences in symptoms or signs for any other analysis performed in this review at the one- to four-week time point. Adverse events No trial reported any intervention-related, vision-threatening adverse events.

AUTHORS' CONCLUSIONS

LipiFlow performs similarly to other commonly used DED treatments with regard to DED signs and symptoms. The best available evidence was deemed to have a high level of bias, leading to low or very low certainty evidence. Additional research with adequate masking, a standardized testing methodology, and a sample representative of the MGD population is therefore needed before any firm conclusions can be drawn regarding comparative benefits and harms.

LipiFlow for the treatment of dry eye disease

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the effectiveness of the LipiFlow Thermal Pulsation System on dry eye signs and symptoms compared to placebo or other commercially available treatments for meibomian gland dysfunction in adults.

Human precorneal tear film and lipid layer dynamics in meibomian gland dysfunction

PURPOSE

To evaluate the precorneal tear film (PCTF) and lipid layer (TFLL) thicknesses and thinning rates in meibomian gland dysfunction (MGD) using a combined ultra-high-resolution optical coherence tomography (OCT) and thickness dependent fringe (TDF) interferometry system.

METHODS

Based on the Tear Film and Ocular Surface Society (TFOS) International Workshop on Meibomian Gland Dysfunction diagnostic algorithm, the Ocular Surface Disease Index (OSDI) and meibum grade score (MGS) were used to classify subjects into four groups: Normal (OSDI<13 and MGS<10), MGD (OSDI≥13 and MGS≥10), Asymptomatic MGD (OSDI<13 and MGS≥10), and Mixed (OSDI≥13 and MGS<10). The OCT/TDF system was used to capture PCTF and TFLL thicknesses and thinning rates. Kruskal-Wallis was used to compare median PCTF and TFLL thicknesses and thinning rates.

RESULTS

There were 190 subjects categorized into four groups: Normal (n = 63), MGD (n = 51), Asymptomatic MGD (n = 29), and Mixed (n = 47). The PCTF was significantly thinner in the Mixed group (3.3 [1.2]) than in the Normal (p < 0.001), MGD (p < 0.001) and Asymptomatic MGD (p = 0.009) groups. Relative to the Normal (4.5 [4.5] μm/min) and Mixed (5.0 [2.0] μm/min) groups, the rate of PCTF thinning was faster in the MGD (8.1 [3.0] μm/min, both p < 0.001) and Asymptomatic MGD (6.9 [3.1] μm/min, p = 0.009 and p = 0.04, respectively) groups. The correlation between PCTF thinning rate and TFLL thickness was ρ = -0.46, p < 0.001.

CONCLUSIONS

Symptomatic and asymptomatic MGD shows rapid PCTF thinning rates (evaporation), while the PCTF thickness was reduced in mixed disease. Thicker lipid layers were associated with slower PCTF thinning.

Impact of modulus of elasticity of silicone hydrogel contact lenses on meibomian glands morphology and function

Clinical relevance: It is important to investigate the effect of modulus of silicone hydrogel contact lens on meibomian glands. Evaluating meibomian gland health and function in follow-up appointments should be considered, with the option of changing lens modulus.Background: To evaluate and compare the effect of modulus of elasticity of silicone hydrogel contact lenses on morphological and functional parameters of the meibomian glands.Methods: A prospective study was conducted on soft silicone hydrogel contact lens wearers of different modulus of elasticity and age and gender-matched controls. Morphological and functional parameters were assessed along with standard patient evaluation of the eye dryness questionnaire.Results: A statistically significant difference was noted in meibomian gland loss in the upper lid (percent) between the low modulus (18.23 ± 6.63) and high modulus group (27.40 ± 10.21) (p < 0.001) and between high modulus (27.40 ± 10.21) and non-contact lens wearers (19.57 ± 7.65) (p = 0.001). The current study reported significantly higher total meiboscore grading in the high modulus group 3 (2-3) compared to the low modulus 2(2-3) (p = 0.007) and non-contact lens wearing groups 2 (2-3) (p = 0.012). Meibum quality was significantly compromised in the high modulus group 1 (0-1) compared to the low modulus 0 (0-0.75) group (p = 0.01). Standard patient evaluation of the eye dryness questionnaire was found to be significantly higher (p = 0.01) in high modulus 4 (2-8) compared to low modulus wearers 2 (2-4). A significant difference was noted (p < 0.001) in corneal staining grading only between high modulus 0 (0-1) and non-contact lens wearers 0 (0-0) group. A positive correlation was noted in the low modulus group between total meiboscore and meibomian gland expressibility (Rs = +0.69, p < 0.001) and also noted between standard patient evaluation of the eye dryness questionnaire scoring and meibomian gland expressibility (Rs = +0.45, p = 0.012) in the high modulus group.Conclusion: Higher modulus of elasticity of silicone hydrogel contact lens may influence meibomian gland morphology and function over a period of contact lens wear.

Ocular Surface Workup in Patients with Meibomian Gland Dysfunction Treated with Intense Regulated Pulsed Light

The purpose of the present study was to evaluate changes of signs and symptoms in patients with meibomian gland dysfunction (MGD) treated with intense regulated pulsed light (IRPL), and to further investigate which parameter could predict positive outcomes of the procedure. Twenty-eight patients who bilaterally received three IRPL sessions at day 1, 15, and 45 satisfied the criteria and were included in the study. Non-invasive break-up time (NIBUT), lipid layer thickness (LLT), meibography, tear osmolarity, and ocular discomfort symptoms were measured before and 30 days after the last IRPL session. Qualified or complete success was defined in the presence of an improvement of symptoms associated with an increase of NIBUT (< or ≥ 20%). After IRPL treatment, median NIBUT and LLT increased from 7.5 to 10.2 s and 2.0 to 3.0, respectively (p <0.001); tear osmolarity decreased from 304.0 to 301.0 mOsm/L (p = 0.002). Subjective symptoms improved after IRPL in 26 patients. Qualified success was reached in 34 eyes, while complete success in 16 eyes. Patients with lower baseline break-up time (BUT) values showed better response to treatment (p = 0.04). In conclusion, IRPL improved signs and symptoms in MGD patients, while lower baseline NIBUT values were predictive of better response to IRPL.

Tear film evaluation and management in soft contact lens wear: a systematic approach

The human tear film is a highly ordered structure consisting of a thin layer of lipid on the surface and a thicker aqueous-mucin phase, which increases in mucin concentration toward the corneal epithelial cell layer. The health of the tear film and ocular surface influences the likelihood of being able to achieve successful contact lens wear. Contact lens discomfort and dryness are the most frequent reasons why contact lens wearers experience reduced wearing times, which can eventually lead to contact lens discontinuation. Comprehensive clinical assessment of tear film integrity and ocular surface health is therefore essential prior to commencing contact lens wear, to enable the ocular surface environment to be optimised to support lens wear. These parameters should also be evaluated over the course of contact lens wear, in order to identify any aspects requiring clinical management and ensure maintenance of optimal lens-wearing conditions. This review summarises current knowledge relating to the effects of soft contact lens wear on the tear film and ocular surface. It also provides a systematic approach to evaluating tear film and ocular surface integrity, in order to guide the clinical management of tear film anomalies with respect to contact lens wear.

Differential Profiling of T-Cell Cytokines as Measured by Protein Microarray Across Dry Eye Subgroups

PURPOSE

The purpose of this study is to explore the role of the adaptive immune system in patients with aqueous-deficient dry eye (ADDE) and lipid-deficient dry eye (LDDE).

METHODS

Patients (n = 29) with moderate to severe dry eye (dry eye workshop [DEWS] severity grading scheme) were enrolled in a cross-sectional study and classified as ADDE (Schirmer < 10), LDDE (abnormal meibum), combined (meeting both criteria), or generic (meeting neither criterion). Tears were collected by Schirmer strips, and samples for both eyes were pooled for each subject. Thirty micrograms of total protein was used in a normalized volume for microarray analysis (Quantibody Human Inflammation Array 3; RayBiotech). Six markers of TH1 cells (interferon [IFN]γ, interleukin [IL]-2), TH2 cells (IL-4, IL-5, IL-13), and TH17 cells (IL-17) were assessed.

RESULTS

ADDE demonstrated the highest total cytokine concentration, followed by the LDDE, combined, and generic groups. IFNγ and IL-2 were detectable in all subgroups. IL-4, -5, and -13 were detectable in ADDE and LDDE, but only IL-13 was detected in both the combined and generic groups. IL-17 was present in the ADDE, LDDE, and combined groups.

CONCLUSIONS

TH1 cells seem to be involved in all forms of dry eye. ADDE and LDDE seem to be mediated by TH1, TH2, and TH17 cells. The combined-mechanism group is mediated by TH1 and TH17 cells, and generic dry eye seems to be mediated by TH1 cells only. ADDE has the greatest overall T-cell-mediated pathophysiology compared with the other subgroups, which is consistent with previous reports of improved efficacy with antiinflammatory therapy in these patients.

Tear film osmolarity and dry eye disease: a review of the literature

Objective

To evaluate the evidence in the peer-reviewed literature regarding the use of tear osmolarity as a physiological marker to diagnose, grade severity, and track therapeutic response in dry eye disease (DED). In addition, to review the evidence for the role of tear osmolarity in the pathophysiology of DED and ocular surface disease.

Methods

A literature review of all publications after the year 2000, which included the keywords “tear osmolarity”, was conducted. Relevant articles were graded according to quality of evidence and research, using the University of Michigan Practice Guideline and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) rating systems. Articles were further categorized by the nature of any reported financial support and by the overall impression they provided related to tear osmolarity.

Results

A total of 164 articles were identified as relevant to the search criteria, although some were editorials, and some were written in a foreign language. Of the total, it was possible to grade 159, and an overall impression was generated for 163. A positive impression of tear osmolarity in DED diagnosis was evident in 72% (117/163) of all articles, with a neutral impression in a further 21% (35/163); 7% had a negative impression. The percentage of positive impressions appeared independent of the quality of research; 73% (38/52) of articles graded high/moderate quality supported the use of tear film osmolarity measurement in DED diagnosis. Impressions were also independent of the source of financial support, with 72% (75/104) of independent studies positive.

Conclusion

The literature broadly supports the use of tear film osmolarity as an objective numerical measure for diagnosing, grading severity, and managing treatment of DED.