Evaluation of Meibomian Gland Structure and Function in Patients with Vernal Keratoconjunctivitis Using Non Contact Meibography and Lipid Layer Interferometry.

PURPOSE: This study evaluated the structural and functional impact of vernal keratoconjunctivitis (VKC) on meibomian glands (MGs) using a combination of noncontact meibography and lipid layer interferometry. METHODS: In this observational study 50 patients with moderate persistent or severe VKC and 50 age-matched controls underwent MG imaging and lipid layer thickness (LLT) measurements with Lipiview II. Image J software was used to assess MG loss (meibograde) in both lids. All patients underwent dry eye evaluation comprising tear break-up time (TBUT), ocular surface staining (OSS), Schirmer I scoring, and meiboscoring (expressibility and quality of meibum secreted). RESULTS: Meibograde, OSS score, and meiboscore was higher in cases (2.68 ± 0.96, 0.580 ± 1.07, and 0.56 ± 0.95 respectively) than controls (1.80 ± 0.67, 0.00 ± 0.00, 0.22 ± 0.47 respectively) (p < 0.001, 0.001, 0.025 respectively). LLT and TBUT was lower in cases (54.58 ± 9.43 nm and 4.92 ± 3.09 sec respectively) than controls (70.14 ± 22.50 nm and 12.02 ± 2.73 sec respectively) (both p's = 0.001). Both groups had comparable Schirmer I scores. CONCLUSION: Children with VKC have significant MG dropouts, deterioration in meibum quality and a thinner and less stable tear film. VKC patients are thus prone to a vicious cycle of inflammation attributable both to the allergic component and to deterioration in MG structure and function. Co-management of MG dysfunction warrants as much attention as the allergic component itself.

Quantitative evaluation of morphological and functional changes in meibomian glands and lipid layer thickness in patients with and without keratoconus.

PURPOSE: To quantitatively evaluate the morphological parameters of meibomian glands (MGs) and lipid layer thickness (LLT) in patients with keratoconus (KC). METHODS: In this prospective, cross-sectional study, 164 eyes of 164 keratoconus patients and 64 eyes of 64 age-matched control subjects were included. An advanced automatic MG analyzer was used to quantitatively measure the morphological and functional parameters of MGs. Morphological and functional parameters of MGs, LLT, and other ocular surface parameters were compared between the control and KC groups. RESULTS: The mean meibomian gland diameter, length, square, and gland area ratio (GA) were all significantly decreased in the KC group (all P < 0.05), while no significant difference was observed in the gland tortuosity index (TI) and gland signal index (SI) between the KC and control groups (all P > 0.05). There was no significant difference in the number of total and incomplete blinking among patients with different stages of keratoconus (all P > 0.05). The gland diameter, square, and TI were all negatively associated with KC severity (all P < 0.05), while no significant difference was observed among all stages of KC in gland length, GA, and SI (all P > 0.05). Moreover, the LLTs were positively correlated with the gland diameter, square, GA, and TI and negatively correlated with anterior corneal curvature or KC severity (all P < 0.05). CONCLUSIONS: Atrophic morphological changes in the meibomian glands were closely correlated with the severity of keratoconus. Gland diameter may be a sensitive functional morphology metric of meibomian glands in patients with keratoconus.

Categorization of Meibomian Gland Dysfunction Using Lipid Layer Thickness and Meibomian Gland Dropout in Dry Eye Patients: A Retrospective Study.

PURPOSE: In the present study, we determined the prevalence of obstructive meibomian gland dysfunction (MGD), hyposecretory MGD, grossly normal MG, and hypersecretory MGD in patients with dry eye syndrome using lipid layer thickness (LLT) and MG dropout. METHODS: Eighty-eight patients with dry eye syndrome were included in the study. Patients were categorized into four groups according to the LLT and weighted total meiboscore. The proportion of patients in each group was calculated. The age, sex, Ocular Surface Disease Index, LLT, Schirmer, tear film breakup time, cornea stain, weighted total meiboscore, expressibility, and quality of meibum were compared between the four groups. RESULTS: Fifteen eyes (17.0%) had obstructive MGD, two eyes (2.3%) had hyposecretory MGD, 40 eyes (45.5%) had grossly normal MG, and 17 eyes (19.3%) had hypersecretory MGD. The obstructive MGD group was younger than the grossly normal MG group. In obstructive MGD, the ratio of men to women was higher than that of the other groups. However, Ocular Surface Disease Index, Schirmer, tear film breakup time, and corneal stain did not show statistically significant differences between the four groups. The meibum expressibility of the hyposecretoy MGD group was worse than those of the other groups. The meibum expressibility of the hyposecretoy MGD group was poor than those of the obstructive and hypersecretory MGD group. CONCLUSIONS: This categorization was expected to help determine the best treatment method for dry eye syndrome, according to the MG status.

Investigating the Impact of COVID-19 Infection on Dry Eye Parameters.

PURPOSE: This study aims to compare dry eye parameters before and after COVID-19 infection in dry eye patients. METHODS: We included 44 dry eye patients (88 eyes) from our existing dry eye cohort, with 22 belonging to the post-COVID-19 group due to a prior COVID-19 infection and the other 22 forming the non-COVID-19 group as they had no history of COVID-19. We examined and compared the dry eye parameters of the post-COVID-19 group, including the ocular surface disease index (OSDI), Schirmer's test results (ST), non-invasive Keratography tear break-up time (NIKBUT), lipid layer thickness (LLT), Meibomian gland dysfunction (MGD), and the grading of papillae and follicles, both before and after the COVID-19 infection. We also compared the dry eye parameters difference of the post-COVID-19 group with the non-COVID-19 group. RESULTS: The post-COVID-19 group was comprised of individuals with an average age of 38.36 ± 14.99 years, of which 82% were female. The time interval between the two tests was 16.92 ± 5.40 months, which did not differ significantly from the non-COVID-19 group. Compared to the pre-COVID-19 eyes, the post-COVID-19 eyes showed a significant decrease in the average LLT (52.86 ± 18.00 nm vs. 63.00 ± 22.40 nm, p < 0.001), as well as the maximum LLT (67.89 ± 20.81 nm vs. 78.48 ± 20.55 nm, p < 0.001). The MGD in both the upper (1.75 ± 0.84) and lower eyelids (1.43 ± 0.73) worsened after a COVID-19 infection. Additionally, the grading of papillae was worse following a COVID-19 infection (0.61 ± 0.69 vs. 0.16 ± 0.37, p < 0.001). The multivariate linear regression model revealed a negative association between COVID-19 infection and NIKBUT-average (ß = -2.98, 95%CI: (-5.82, -0.15), p = 0.039), LLT-average (ß = -14.12, 95%CI: (-22.66, -5.59), p = 0.001), and LLT max (ß = -15.65, 95%CI: (-23.09, -8.20), p < 0.001). CONCLUSION: From preliminary results, we concluded that dry eye patients who have been infected with COVID-19 appear to have a more severe dry eye condition, as evidenced by lower LLT, worse papillae and MGD, and shorter NIKBUT. It is important to raise awareness of this potential long-term symptom of COVID-19, especially among existing dry eye patients.

Lacrimal and meibomian gland evaluation in dry eye disease: A mini-review.

Lacrimal and meibomian glands contribute to the aqueous and lipid components of tear film, respectively. Their evaluation remains central to diagnosing and managing dry eye disease (DED). The review discusses the differences and reliability of various diagnostic tests and commercially available devices used for DED diagnosis. Slit-lamp-based techniques are direct palpebral lobe and tear flow assessment, Schirmer test, meibum quality and expressibility, and evaluation of tear meniscus height. Non-invasive tear meniscus height (TMH), tear break-up time (TBUT), lipid layer thickness (LLT), and meibography are machine-based diagnostic tests. The structure-function correlation of the tear-producing glands gives more comprehensive details than either information alone. Many devices are available in the market, which make DED diagnosis an easy feat, but the tests should be interpreted keeping in mind the intra-observer and inter-observer repeatability. Also, the tear film displays a huge variability as per the environmental conditions and impact of blinking. Hence, the examiner should be well versed with the techniques and repeat the test two to three times to obtain an average reading, which is more reliable. The recommended sequence of tests for diagnosing DED is a dry eye questionnaire, TMH, LLT, NIBUT (FBUT if non-invasive test is unavailable but should be performed after osmolarity), tear osmolarity, meibography, and ocular surface staining. Invasive tests such as Schirmer should be performed after the non-invasive tear film diagnostic testing.

Differential characteristics among asymptomatic and symptomatic meibomian gland dysfunction and those with dry eye.

PURPOSE: To identify the characteristics of asymptomatic meibomian gland dysfunction (MGD), symptomatic MGD, and MGD coexisting with dry eye disease (DED). METHODS: This cross sectional study enrolled a total of 153 eyes of 87 MGD patients. Participants filled in ocular surface disease index (OSDI) questionnaires. Age, gender, Schirmer's test, meibomian gland (MG) related parameters, lipid layer thickness (LLT) and blinking were compared among patients with asymptomatic MGD, symptomatic MGD, and MGD with DED. Multivariate regression was used to analyze the significant factor of DED in MGD. Spearman's rank correlation analysis was used to evaluate the association between the significant factors and MG function. RESULTS: There was no difference in age, Schirmer's test, lid changes, MG secretion, and MG morphology among three groups. The OSDI of asymptomatic MGD, symptomatic MGD and MGD coexisting with DED were 8.5 ± 2.9, 28.5 ± 12.8 and 27.9 ± 10.5, respectively. Patients with MGD coexisting with DED exhibited more frequent eye blinking than that of patients with asymptomatic MGD (8.1 ± 4.1 vs. 6.1 ± 3.5 blinks/20 sec, P = 0.022), and reduced LLT than that of patients with asymptomatic MGD (68.6 ± 17.2 vs. 77.6 ± 14.5 nm, P = 0.010) and symptomatic MGD (78.0 ± 17.1 nm, P = 0.015). Multivariate analysis identified LLT (per nm, OR = 0.96, 95% CI = 0.93-0.99, P = 0.002) as a significant factor associated with DED development in MGD. The number of expressible MG was positively correlated with LLT (Spearman's correlation coefficient = 0.299, P = 0.016) but negatively correlated with the number of blinking (Spearman's correlation coefficient = -0.298, P = 0.016) in MGD patients with DED, and these findings were not identified in those without DED. CONCLUSIONS: Asymptomatic MGD, symptomatic MGD, and MGD coexisting with DED share similar characteristics, including meibum secretion and morphology, but MGD patients coexisting with DED exhibited significantly reduced LLT.

Correlation Between Air Quality Index and Tear Film Lipid Layer Thickness: Comparison Between Patients with Sjogren's Syndrome and with Meibomian Gland Dysfunction.

PURPOSE: To evaluate the effect of air pollution on the tear film stability by analyzing the correlation between Air Quality Index (AQI) and Lipid Layer thickness (LLT) in Xuzhou. METHODS: As a prospective descriptive observational study, 284 patients with meibomian gland dysfunction (MGD), 157 patients with Sjögren's syndrome (SS), and 264 healthy volunteers were included. The tear film lipid layer thickness of the three groups of subjects was measured weekly and compared with the air quality index to analyze the correlation between the two indicators. Logistic regression analysis and linear regression analysis were used to analyze the effect of AQI on the thickness of the tear film lipid layer. The change of LLT with air pollution at different AQI levels was also analyzed. RESULTS: There are obvious seasonal differences in the changes of air pollution index in Xuzhou. Significant differences could be observed in the thickness of the lipid layer of the tear film among the three groups. LLT in the MGD group and SS group decreased with the aggravation of air pollution, while remained unchanged in the control group. There was strong evidence of correlation between LLT of the MGD group (F = 353.494, p < 0.01, adjusted R2 = 0.695) and the SS group (F = 502.404, p < 0.01, adjusted R2 = 0.764) with AQI, while there was minor correlation between LLT with AQI in control group (F = 8.525, p < 0.01, adjusted R2 = 0.046). CONCLUSIONS: Air pollution can cause a decrease in the thickness of the tear film lipid layer, thereby affecting tear film stability, leading to the occurrence of dry eye.

Transcutaneous Electrical Stimulation for the Prevention of Dry Eye Disease after Photorefractive Keratectomy: Randomized Controlled Trial.

Objective: To evaluate the efficacy and safety of transcutaneous electrical stimulation (TES) for the prevention of dry eye after photorefractive keratectomy (PRK). Design: Prospective, single-center, single-blinded, parallel group, placebo-controlled, randomized clinical trial. Participants: Between February 2020 and October 2020, patients at the Samsung Medical Center scheduled to undergo PRK to correct myopia were screened and enrolled. Methods: The participants in the TES group were instructed to use the electrical stimulation device (Nu Eyne 01, Nu Eyne Co) at the periocular region after the operation, whereas those in the control group were to use the sham device. Dry eye symptoms were evaluated preoperatively and postoperatively at weeks 1, 4, and 12 using the Ocular Surface Disease Index (OSDI) questionnaire, the 5-Item Dry Eye Questionnaire (DEQ-5), and the Standard Patient Evaluation for Eye Dryness II (SPEED II) questionnaire. Dry eye signs were assessed using tear break-up time (TBUT), total corneal fluorescein staining (tCFS), and total conjunctival staining score according to the National Eye Institute/Industry scale. The pain intensity was evaluated using a visual analog scale. Main Outcome Measures: Primary outcomes were OSDI and TBUT. Results: Twenty-four patients were enrolled and completed follow-up until the end of the study (12 patients in the TES group, 12 patients in the control group). Refractive outcomes and visual acuity were not different between the groups. No serious adverse event was reported with regard to device use. No significant difference in OSDI and SPEED II questionnaires and the DEQ-5 was observed between the groups in the 12th week after surgery. The TBUT scores 12 weeks after the surgery were 9.28 ± 6.90 seconds in the TES group and 5.98 ± 2.55 seconds in the control group with significant difference (P = 0.042). The tCFS and total conjunctival staining score were significantly lower in the TES group than in the control group at postoperative 4 weeks. Pain intensity at the first week was significantly lower in the TES group than in the control group by 65% (P = 0.011). Conclusion: The application of TES is safe and effective in improving dry eye disease after PRK. Financial Disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Assessment of condition-induced changes on the ocular surface using novel methods to assess the tear film dynamics and the lipid layer.

OBJECTIVES: To assess the effects of different condition-induced changes on current and novel ocular surface metrics. METHODS: Eighty-four healthy volunteers (22.4 ± 2.6 years) participated in this study. The ocular surface and tear film response to (1) computer use, (2) contact lens insertion and (3) tear film instillation during computer use with contact lenses were assessed. Current metrics included the ocular surface disease (OSDI) questionnaire, 5-item dry eye questionnaire (DEQ-5), bulbar redness, tear meniscus height (TMH) and non-invasive keratograph break-up time (NIKBUT). Novel metrics included the lipid layer thickness obtained from the intensity of the reflected Placido disk and the speed of tear film particles post-blink. RESULTS: Higher dry eye symptoms, TMH and bulbar redness, and lower values in metrics related to the intensity of the Placido disk pattern and to particle speed were found after the computer reading task (p < 0.036). When a contact lens was fitted, lower TMH, NIKBUT and particle speed metrics were obtained (p < 0.044). Mixed ANOVA revealed that artificial tears significantly ameliorated the effect of computer reading on OSDI, DEQ-5, NIKBUT, metrics related to the intensity of the Placido disk pattern and metrics related to particle speed (p < 0.033). CONCLUSIONS: Computer use and contact lens wear worsened dry eye signs and symptoms, but artificial tears ameliorated this effect. Newly developed methods can serve as a tool to detect changes in the tear film triggered by different ocular surface-disturbing conditions.

Influence of short-term face mask wear on semiautomatically measured tear film parameters in dry eye patients and healthy volunteers.

PURPOSE: The use of face masks has been proposed to cause or exacerbate the symptoms of dry eye disease (DED), which has been widely discussed under the term mask-associated dry eye (MADE). However, no studies have systematically investigated tear film parameters during the use of different face masks. Therefore, the objective of the present study was to investigate clinically relevant parameters of the tear film before and during the short-time use of face masks in dry and normal eyes. METHODS: In a prospective study, the tear film parameters of 42 DED patients and 42 healthy volunteers were examined while wearing different types of face masks in a randomized order. This included measurements of non-invasive tear break-up time (NIBUT), lipid layer thickness, tear meniscus height, and bulbar redness after 30 min of wearing no mask, a surgical face mask or an FFP2/K95 mask. The equivalence of the means was assessed using the two one-sided t-test (TOST) method. RESULTS: In healthy volunteers' lipid layer thickness, NIBUT and tear meniscus height were not significantly altered by 30 min of surgical or FFP2 mask wear (p > 0.016). The use of either type of mask was significantly associated with decreased bulbar redness (p < 0.001) in healthy eyes. In patients with DED, none of the tear film parameters or bulbar redness were significantly altered by 30 min of mask wear (p > 0.016). CONCLUSIONS: Based on these results, the short-term wearing of face masks, regardless of type, did not produce a significant difference in tear film parameters of lipid layer thickness, NIBUT, and tear meniscus in healthy or dry eyes, while bulbar redness was reduced after mask wear only in healthy volunteers.

Tobacco effects on ocular surface, meibomian glands, and corneal epithelium and the benefits of treatment with a lipid-based lubricant.

PURPOSE: Our aim was to evaluate the ocular surface in chronic smokers and to assess the benefit of sodium hyaluronate (SH) versus semi-fluorinated alkane (SFA) eyedrops on tear film, meibomian glands, and corneal epithelial thickness (CET). METHODS: This prospective randomized single-blinded study included smokers, who applied one eyedrop of Hyabak® on one eye (SH group) and one eyedrop of EvoTears® on the fellow eye (SFA group) 4 times daily for 2 months, and age-matched non-smokers. Ocular surface parameters, including tear film break-up time (TBUT) test and corneal fluorescein staining (CFS) score, lipid layer thickness (LLT), meibography (LipiView®), and CET measurements (Zeiss Cirrus HD-5000®), were assessed at baseline and after treatment. RESULTS: Seventy-eight eyes were included in the smokers group (39 in the SH subgroup and 39 in the SFA subgroup) and 42 eyes in the control group. At baseline, the smokers group had a higher prevalence of dry eye (100% vs 0%, p < 0.001) and of meibomian gland dysfunction (MGD) and lower CET measurements than controls (p < 0.05). TBUT, CFS, and LLT (controls vs SFA group: 64.02 ± 1.87 nm vs 49.56 ± 4.33 nm, p = 0.05) improved in the SFA subgroup after treatment, but not in the SH subgroup, and became equivalent to those of controls. Prevalence of dry eye decreased in the smokers group after treatment (controls vs SH group vs SFA group: 0% vs 12.82% vs 16.26%, p > 0.05). Meibomian gland morphological parameters and CET did not improve after treatment (p < 0.05). CONCLUSIONS: Smoking is associated with dry eye, MGD, and corneal epithelial thinning that seem to be only partially reversible with topical lubricants, preferably SFA.

Evaluation of lipid layer tear film changes after femtosecond small incision lenticule extraction.

Background: Dry eye disease is common after refractive procedures due to tear film instability. There are several causative factors for tear film instability, but the state of individual components of the tear film is not assessed much in published literature. This article quantifies the lipid layer thickness (LLT) of the tear film using surface interferometry before and after the small incision lenticule extraction (SMILE) refractive procedure. Objectives: This study aimed to evaluate the effects of femtosecond SMILE on the postoperative stability of the LLT of the tear film. Design: This was a prospective, interventional, non-case-control study. Methods: A total of 160 eyes of 80 patients were enrolled in the study. The follow-up period was 6 months after surgery. A noninvasive surface interferometer was used to measure the thickness of the lipid layer before surgery and was repeated at 3 and 6 months after surgery. The main outcome measure was the change in average LLT at 3 and 6 months after SMILE and its statistical significance. Results: There were 48 women and 32 men. Age ranged from 21 to 42 years (mean = 27 ± 6.4). Mean LLT at baseline was [oculus dextrus (OD) = 53.38 (±7.24) nm; oculus sinister (OS) = 52.21 (±6.95) nm], at 3 months [OD = 54.38 (±5.75) nm; OS = 53.26 (±5.70)], and at 6 months [OD = 53.31 (±5.66) nm; OS = 52.39 (±5.94)]. Mean LLT showed mild improvement at 3 months after surgery (OD = 53.38-54.38 mm, p = 0.0417; OS = 52.21-53.26 mm, p = 0.0398). There was no significant change in LLT from the baseline before surgery to levels 6 months after surgery (p = 0.8914 OD; p = 0.7368 OS). Conclusion: The SMILE refractive procedure did not alter the LLT that remained stable and adequate at 6 months postoperative follow-up.

Decrease in Tear Film Lipid Layer Thickness in Patients with Keratoconus.

Keratoconus (KC) is a progressive corneal disorder characterized by thinning and protrusion, mostly of the inferotemporal and central corneal regions. Dysfunction of the meibomian gland, the excretions of which form the lipid layer of the tear film, has been reported to be associated with KC. Thus, this manuscript investigates the correlation among lipid layer thickness (LLT), partial blink rate (PBR), and KC of different degrees. This retrospective study included 54 patients and 24 healthy controls. The anterior corneal curvature, LLT, and PBR were taken from the unilateral eye of all 78 participants. The difference in those ocular parameters between the moderate and severe groups and the control group is significant. No significant association was found between anterior corneal curvature and LLT (r = −0.2, p = 0.15) across all the patients. However, there was a significant negative correlation between anterior corneal curvature and LLT in moderate (r = −0.6, p < 0.05) and severe (r = −0.7, p < 0.05) keratoconus cases. The results also show a significant negative correlation between anterior corneal curvature and PBR (r = −0.41, p < 0.05). Therefore, we conclude that the severity of keratoconus is associated with the thinning of LLT and the reduction of PBR. This may relate to a further epithelial abnormality with the reduced protection of tear film from the air, leading to the release of proteolytic enzymes that degrade stromal collagen and weaken the cornea.

The effect of hydroxypropyl-guar nanoemulsion on signs and symptoms of dry eye.

PURPOSE: To examine the effect of hydroxypropyl-guar nanoemulsion (HP-Guar nanoemulsion, Alcon Laboratories Ltd, Fort Worth, TX, USA) versus saline (0.9% sodium chloride; Pfizer Inc., Bentley WA Australia) on the comfort and tear film properties of people with dry eye disease both in the short-term (up to 2 h post-drop instillation) and longer-term (after 4 weeks of 4-times daily use), and to examine the effect on tear inflammatory markers after 4 weeks. METHODS: This was a prospective, investigator-masked, randomised, cross-over dispensing study. Twenty participants with dry eye disease (5 males: 15 females) with average age 46.9 ± 14.4 (range 26 to 70) years were randomized to either HP-Guar nanoemulsion, or saline eye drops. Ocular symptoms, lipid layer thickness, tear evaporation, tear osmolarity and non-invasive break-up time were measured pre-drop instillation, 1 h and 2 h post-eye drop instillation, and after 4-weeks of 4-times daily drop use. Tear inflammatory mediators were measured pre-drop instillation and after 4-weeks. After 4-weeks, patients had a 4-week washout period and then crossed over to the alternate drop. RESULTS: With HP-Guar nanoemulsion, participants reported less grittiness/burning/stinging 1 h post eye drop instillation compared to baseline (79.5 ± 23.3 vs. 66.8 ± 27.7, p = 0.02); less dryness 1 h and 2 h post eye drop instillation compared to baseline (77.8 ± 23.0 and 76.2 ± 23.7 vs. 61.0 ± 27.1 respectively, p < 0.01 for both); and greater overall satisfaction 1 h post drop instillation and after 4 weeks of daily use compared to baseline (80.4 ± 21.6 and 83.4 ± 16.6 vs. 68.6 ± 26.0 respectively, p ≤ 0.011 for both). With saline, participants reported less dryness after 4 weeks of daily use compared to baseline (74.2 ± 23.8 vs. 60.2 ± 24.0, p < 0.01). For HP-Guar nanoemulsion, average lipid layer thickness was significantly thicker 2 h post drop-instillation (79.5 ± 21.7 nm) compared to baseline (63.7 ± 18.9 nm) and the 4-week assessment (62.4 ± 23.1 nm, p < 0.01 for both). For saline, average lipid layer thickness was significantly thicker at 1 h and 2 h post eye drop instillation (76.0 ± 23.8 nm and 80.4 ± 24.8 nm) compared to baseline (61.0 ± 15.6 nm, p < 0.01 for both). There was no difference in inflammatory mediators or other tear variables between drops or visits. CONCLUSION: HP-Guar nanoemulsion was more effective for improving a range of subjective dry eye symptoms both in the short and long-term compared to saline. Both HP-Guar nanoemulsion and saline transiently increased lipid layer thickness.

Tear film lipid layer thickness measurement from Ocular Surface Analyzer as a marker to monitor treatment of meibomian gland dysfunction in a study comparing physiological detergent-free eyelid wipes with conventional therapy: A randomized trial.

Purpose: To compare the efficacy of physiological, non-detergent eyelid wipes with conventional lid hygiene in patients with meibomian gland dysfunction (MGD). Methods: Fifty participants with MGD were recruited and randomized into two groups. Participants in group I used Evolve Pure™ Eyewipes twice a day to clean the eyelid debris along with standard therapy (antibiotic and lubricants) and participants in group II followed lid hygiene with warm compresses along with standard therapy. Symptoms, ocular surface assessment (lipid layer thickness, tear meniscus height, non-invasive tear film breakup time, and meibography), slit-lamp biomicroscopy (eyelash contamination, meibomian gland blockage, meibomian gland secretion, and meibomian gland telangiectasia) and tear film osmolarity were noted at baseline and 90 days after therapy. Results: Significant improvement in symptoms and signs of MGD was observed in both groups after treatment (P < 0.001); however, the clinical improvement was better with the use of eyelid wipes. Lipid layer thickness increased significantly in group I (P = 0.0006) and group II (P = 0.0002), which was maintained even after adjusting for sociodemographic variables such as age, sex, and severity score of symptoms and signs. Conclusion: Lipid layer thickness of the tear film is a sensitive marker in monitoring response to treatment in patients with MGD. The use of physiological detergent-free eyelid wipes is non-inferior to lid hygiene and warm compresses, which remains the mainstay for treatment of MGD; the clinical improvement with eyelid wipes was noted to be better.

Immediate Ocular Changes After Light-Emitting Diode Displays Exposure-A Preliminary Study.

Purpose: Computer vision syndrome (CVS) is one of the most frequently encountered problems among video display terminals (VDT) users, but little is known regarding the short-term effect after exposure to light-emitting diodes (LED). The purpose of this study was to determine if short-term exposure to LED leads to changes in corrected distance visual acuity (CDVA), lipid layer thickness (LLT), blink rates, partial blink ratio, and computer vision syndrome questionnaire (CVS-Q) score. Design: Prospective, cross-sectional study. Methods: In this study, participants were recruited at the National Cheng-Kung University Hospital, a tertiary referral center in southern Taiwan, for examination. Participants were asked to complete the CVS-Q and undergo a series of ocular examinations, including CDVA, LLT, blink rates and partial blink ratio before and after watching an LED display for 15 min. Main Outcome Measures were changes in CDVA, LLT, blink rates, partial blink ratio, and CVS-Q measurements. Results: In total, 120 eyes from 60 participants (mean age: 35.7 ± 9.4 years) were included; 31 participants were men (51.7%), and 29 were women (48.3%). The CDVA, LLT, blink rates, and partial blink ratio did not change after watching the LED display. The CVS-Q score significantly improved after short-term LED exposure (P < 0.001). A subgroup analysis of subjects with a baseline LLT of <60 nm or ≥60 nm determined that LLT significantly decreased in individuals with a baseline LLT of ≥60 nm (P = 0.016). Conclusion: Short-term use of LED displays reduced LLT in individuals with a baseline LLT of ≥60 nm, despite the visual symptoms of CVS improved subjectively. Therefore, digital device users should be aware of the potential negative effects of LED exposure on the eyes.

Lipid layer thickness decrease due to meibomian gland dysfunction leads to tear film instability and reflex tear secretion.

PURPOSE: To determine the clinical effects of ocular surface and Meibomian gland parameters on tear film stability among individuals with Meibomian gland dysfunction (MGD), those with aqueous deficient dry eye (ADDE), individuals with both conditions and normal controls. METHODS: Patients were divided into four groups: normal controls, patients with ADDE, patients with MGD, and patients who fulfilled diagnostic criteria for ADDE and MGD (Mixed Group). Data for ocular symptom score, lid margin abnormality, ocular staining, tear break-up time, meiboscore, and lipid layer thickness (LLT) measured by a Lipiview interferometer, Schirmer test, and MGD severity score were collected. RESULTS: A total of 109 patients (109 eyes) were evaluated. In patients with MGD, LLT was significantly lower than the ADDE patients. However, the Schirmer test value was the highest in the MGD group. The LLT negatively correlated with meiboscore and MGD severity score in the MGD group. Significant correlation between Schirmer test value and meiboscore was definite in the MGD group. CONCLUSIONS: Tear fluid secretion is more increased and lipid layer thickness is more decreased in MGD patients than in ADDE patients. Decreased lipid layer thickness caused by MGD-related tear film instability may stimulate reflex tear secretion. The obstructive MGD is more prevalent than hypersecretary MGD.Key messagesThe tear film stability is affected by Mebomian gland dysfunction (MGD). The measurement of the tear film parameters including lipid layer thickness suggests that the obstructive MGD is more prevalent than hypersecretary MGD and the aqueous layer compensates the decreased lipid layer caused by MGD.

Comparable meibomian gland changes in patients with and without ocular graft-versus-host disease after hematopoietic stem cell transplantation.

PURPOSE: To compare the presentation and severity of meibomian gland dysfunction (MGD) in patients with and without chronic ocular graft-versus-host disease (coGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: This prospective cross-sectional study included 79 patients (47 with coGVHD and 32 without) after allo-HSCT. All participants completed ocular surface disease index questionnaire, and received slit lamp, ocular surface interferometer, meibography and confocal microscopy examination. The prevalence and severity of MGD were compared between two groups and related factors were analyzed. Main outcome measures were lipid layer thickness (LLT) and meiboscore. RESULTS: Similarly high prevalence of MGD was detected in coGVHD and non-coGVHD groups (87.2% vs 84.4%, P = 0.977). Among those with MGD, although patients without coGVHD had longer noninvasive break-up time [5.54 (2.87, 9.37) vs 2.29 (0.00, 3.82) s, P < 0.001], patients in two groups presented similarly decreased LLT (53.5 ± 22.3 vs 47.1 ± 25.2 nm, P = 0.286), increased meiboscore (2.7 ± 1.5 vs 3.5 ± 1.8, P = 0.060) and enlarged acinar unit area (1647.7 ± 942.9 vs 1808.8 ± 1211.5 µm2, P = 0.592). Meibomian gland inflammation and fibrosis were observed in both groups, but more predominant in coGVHD group. Results were consistent when patients within a comparable post-HSCT time interval were compared. Regression analysis revealed neither LLT nor meiboscore was associated with coGVHD severity. LLT was positively correlated with systemic immunosuppressant use (ß = 12.0, P = 0.044), while meiboscore was positively correlated with lymphoma (ß = 1.78, P = 0.040) and matched unrelated donor (ß = 1.59,P = 0.008). CONCLUSIONS: MGD was common and evident in patients after allo-HSCT. MGD is not different between coGVHD and non-coGVHD patients except more inflammation and fibrosis in the former.

Evaluation of the meibomian glands using the tear interferometer wearing orthokeratology lenses.

BACKGROUND: To investigate the impact of orthokeratology wear on meibomian glands in Korean pediatric population using the tear interferometer. METHODS: Fifty-three orthokeratology wearers and 79 non-lens wearers were evaluated using the LipiView® II ocular surface interferometer which shows incomplete blink rate, average lipid layer thickness, and meiboscores. RESULTS: No significant differences in the incomplete blink rate and meiboscores for upper eyelids, but the lipid layer thickness and meiboscores for lower eyelids were significantly higher in the Ortho-K group than in the control group (p = 0.024 and 0.007, respectively). Correlation analysis showed no significant correlation between the duration of orthokeratology wear and the parameters measured by LipiView® (p > 0.05 for all). Among subgroups based on average duration of lens wear, the longer duration (≥ 24 months) subgroup showed higher meiboscores of lower eyelids (p = 0.011), but no other significant differences. CONCLUSIONS: Ortho-K wearers showed no significant differences in the incomplete blink rate and meiboscores of upper eyelids, but they were associated with increased LLT and higher meiboscores of lower eyelids. Thorough examination and close monitoring of orthokeratology wearers is necessary. Prospective and observational studies are needed to further elucidate the relationship between Orthokeratology and meibomian glands.