Noncontact Meibography in Patients with Keratoconus

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.

Influence of midday removal and re-application of a scleral lens on fluid reservoir thickness, pre-lens tear film quality and visual acuity

PURPOSE

To investigate whether the midday removal and re-application of scleral lenses (SL) influences fluid reservoir (FR) thickness, pre-lens tear film quality and visual acuity.

METHODS

Two clinical experiments were conducted. A total of 49 keratoconic eyes were evaluated for Part1(tear film and visual acuity analysis) and 12 keratoconic eyes for Part2 (FR thickness analysis). All subjects were wearing 16.4 mm SL for more than 12-months. Tear Film Surface Quality (TFSQ) was evaluated with Medmont E300 at more than 120 min of SL wear, 10 min after SL removal (pre-corneal TFSQ) and 5 min after re-apply the same SL. High and Low Contrast Visual Acuity (HCVA and LCVA) were also assessed with the SL on eye (before and after re-application). For Part2, Anterior OCT (MOptim MOcean4000, China) measurements were taken with and without the SL (at the same time points of Part1) and three outcomes were evaluated: FR thickness, SL thickness (control measurement) and corneal thickness.

RESULTS

Removing and re-applying a SL had a statistically significant positive impact on TFSQ, with an improvement from 0.26 ± 011 to 0.16 ± 0.08 (p = 0.001). This was accompanied by a statistically significant improvement in LogMAR HCVA (from 0.10 ± 0.09 to 0.08 ± 0.08, p < 0.001) and LCVA (from 0.39 ± 0.13 to 0.36 ± 0.13, p < 0.001). Regarding Part2 of the study, a statistically significant increase in FR thickness was observed after SL re-application (from 223.64 ± 48.08 µm to 267.81 ± 80.03 µm, p = 0.007). No changes in corneal thickness were observed.

CONCLUSIONS

Midday removal and re-application of a scleral lens positively impacted pre-lens tear film surface quality, although the observed improvement in visual acuity does not constitute a clinically significant change. Clinicians should consider that removing and reapplying a scleral lens may result in an overestimation of the fluid reservoir thickness, which could affect clinical assessments and treatment decisions.

[Changes in the precorneal tear film at various stages of keratoconus]

The combination of keratoconus (KC) with signs of dry eye disease (DES) has been described in numerous scientific publications. At the same time, there is a relationship between KC stage and an increase in the severity of DES symptoms, however, there is still no common understanding of the severity of xerotic process depending on the clinical course of keratectasia.

PURPOSE

This study assesses the changes in the state of the precorneal tear film in KC relative to the stages of the disease.

MATERIAL AND METHODS

The study included 50 patients (100 eyes) with bilateral non-operated KC from subclinical to stage IV. The following methods were used for a comprehensive assessment of the condition of the tear film: biomicroscopy of the anterior segment of the eye using vital dyes, functional tests (Norn, Schirmer, Jones tests), tearscopy of the lipid layer of the tear film with software processing of the results, OCT-meniscometry, as well as filling out the OSDI questionnaire by patients.

RESULTS

The following significant changes were revealed as the KC stage progressed: an increase in the area of staining of the ocular surface with vital dyes, a decrease in the results of the Norn functional test and OCT-meniscometry, an increase in the areas of smaller thickness of lipids and areas of their complete absence according to tearscopy, as well as an increase in scores of the OSDI questionnaire.

CONCLUSION

A comprehensive assessment of the condition of the tear film in KC indicates the relationship and the strengthening of the signs of DES as keratectasia progresses, and can be considered as justification for the need to prescribe tear replacement and reparative therapy that improves the condition of the ocular surface and stabilizes the precorneal tear film.

Contact lens wear and follow-up and its association with signs and symptoms of meibomian gland dysfunction

INTRODUCTION

This study investigated the equivocal association between contact lens (CL) wear and meibomian gland dysfunction (MGD) by comparing the morphological, functional and subjective outcomes of CL wearers versus control, non-CL wearers. CL wearers were examined as two cohorts based on the annual attendance of follow-up visits (FLU-attended these visits, whereas non-FLU did not).

METHODS

Habitual logMAR visual acuity, invasive and non-invasive tear break-up time, Schirmer test, Efron grading scales, meibum quality score (MQS), meibum expressibility score (MES), meibomian gland (MG) loss, lid margin abnormalities and subjective dry eye (DE) symptoms were assessed.

RESULTS

Of the 128 participants, 31 were in the FLU cohort, 43 were in the non-FLU cohort and 54 were controls (mean ages: 22.2 ± 3.1, 23.0 ± 4.6 and 22.3 ± 3.5, respectively). Non-FLU CL wearers had more symptoms than controls (3.7 ± 2.4 vs. 2.3 ± 2.1, p < 0.01). Morphologically, FLU (16.9 ± 8.8%, p = 0.02) and non-FLU (18.6 ± 11.3%, p = 0.001) had more MG loss than controls (11.2 ± 6.8%). Functionally, FLU (0.6 ± 0.7, p = 0.01) and non-FLU (0.8 ± 0.9, p = 0.001) had worse MES than controls (0.2 ± 0.5). FLU and non-FLU were both associated with corneal staining (odds ratio [OR] = 3.42, 95% CI: 1.16-10.11, p = 0.03 and OR = 5.23, 95% CI: 1.89-14.48, p = 0.001, respectively) and MG loss (OR = 10.47, 95% CI: 1.14-96.29, p = 0.04 and OR = 16.63, 95% CI: 1.96-140.86, p = 0.01, respectively). Non-FLU CL wear was also associated with abnormal MQS (OR = 12.87, 95% CI: 1.12-148.41, p = 0.04), conjunctival staining (OR = 12.18, 95% CI: 3.66-40.51, p < 0.001) and lid margin telangiectasia (OR = 3.78, 95% CI: 1.55-9.21, p = 0.003). MGD was three times more prevalent in CL wearers (12%) than in controls (4%).

CONCLUSIONS

Both CL-wearing cohorts demonstrated significantly more MG abnormalities than controls though the difference was not clinically significant. Non-FLU CL wearers had more DE symptoms. Non-FLU CL wear is an independent predictor for more abnormalities than FLU CL wear, emphasising the importance of follow-ups.

Non-contact meibography changes according to disease activity in rheumatoid arthritis cases

PURPOSE

To measure dry eye disease (DED) activity in rheumatoid arthritis (RA) patients, correlate it with the activity and duration of RA, and objectively measure the degree extent of DED in RA active cases.

METHODS

The paper studied the meibomian gland of 30 RA cases referred by the Rheumatology Department, Sohag University Hospitals to Sohag Cornea and Refractive Center, Sohag, Egypt, by infrared non-contact meibography in the Scheimpflug topographer (Sirius, CSO, Italy) from July 2021 to July 2022. The cases fulfilled the RA classification criteria according to the 2010 American College of Rheumatology and European League and underwent full lab investigations. They were distributed to two groups based on the DAS-28 questionnaire. The patients were distributed into low to moderate activity (3.2 < score <  = 5.1) and high activity groups (score > 5.1).

RESULTS

This study included 60 eyes of 30 RA patients. They scored a mean age of (44 ± 10 years), number of swollen joints (3 ± 3), number of tender joints (5 ± 3), duration of disease (8 ± 4), activity of the disease measured by DAS-28 (4.4 ± 0.9), and sex (males were 9.7% vs females 90.3%). The number of swollen joints, tender joints, ESR and DAS-28 were more in the high activity group with the p-value of (0.018, 0.001, < 0.003 and < 0.004), respectively. There are no statistically significant differences between both groups as regards disease duration (p-value of 3.8). The high activity group showed significant affection regarding the mebioscore of the lower and upper lids, total mebioscore, percentage of meibomian glands in upper and lower lids, first non-invasive break-up time test (NIV-BUT) of the tear film, as well as average non-invasive break-up time test (NIavg-BUT). There were moderate correlations between the activity of the disease represented by (DAS-28) and different parameters evaluating eye dryness (meiboscore of the lower and upper lids, total meiboscore, percentage of meibomian glands in upper and lower lids, NIV-BUT of the tear film, and NIavg-BUT of the tear film).

CONCLUSION

There was no correlation with duration of RA but moderate correlations between the activity of the disease represented by (DAS-28) and different parameters evaluating eye dryness in RA patients with valuable use of noncontact Meibography to evaluate eye dryness in RA cases. Both Meiboscore and Meiboscale of Non-contact Meibography were found to be useful tools in grading of dry eye disease in different activity grades of Rheumatoid Arthritis.

Evaluation of Corneal Parameters and Meibomian Gland Alterations After Corneal Cross-Linking in Patients With Progressive Keratoconus

OBJECTIVES

The aim of the study was to evaluate the changes in corneal parameters and meibomian gland alterations after corneal cross-linking (CXL) for progressive keratoconus.

METHODS

Thirty nine eyes of 39 keratoconus patients were treated with CXL. Corneal topography, specular microscopy, the Ocular Surface Disease Index© (OSDI), noninvasive tear break-up time (NITBUT), and meibography indices were evaluated preoperatively and at the first, third, and sixth months after CXL.

RESULTS

The flattest keratometry (K1) ( P =0.003), steepest keratometry (K2) ( P <0.001), apex, central, and thinnest corneal thicknesses ( P <0.001) showed significant differences after cross-linking, whereas the changes in the maximum keratometry (Kmax) were not significant ( P =0.140). The endothelial cell density, coefficient of variation, and hexagonality were unchanged. The NITBUT values decreased after cross-linking; however, there was no significant change in OSDI index ( P =0.313), meiboscore ( P =0.392), and meibomian gland loss degrees ( P =0.300). No change was detected in the morphology of the meibomian glands after CXL.

CONCLUSION

In eyes with keratoconus, a flattening in keratometry readings and thinning in corneal thickness were observed after CXL. The corneal endothelium is protected by dextran-free riboflavin. Cross-linking procedure causes dry eye by changing the corneal structure without affecting the morphology of the meibomian glands.

Assessment of meibomian gland drop-out and visibility through a new quantitative method in scleral lens wearers: A one-year follow-up study

OBJECTIVES

To validate a previously developed algorithm based on the visibility of meibomian gland images obtained with Cobra fundus camera and to assess the changes in meibomian glands in scleral lens wearers over one year of lens wear.

METHODS

Infrared meibography was obtained from the upper eyelid using the Cobra fundus camera in forty-three volunteers (34.2 ± 10.1 years). Meibographies were classified into 3 groups: Group 1 = good subjective gland visibility and gland drop-out < 1/3 of the total area; Group 2 = low visibility and gland drop-out < 1/3; and Group 3 = low visibility and gland drop-out > 1/3. Meibomian gland visibility metrics were then calculated using the developed algorithm from the pixel intensity values of meibographies. Repeatability of new metrics and their correlations with gland drop-out were assessed. Meibographies and ocular symptoms were also assessed after 1 year of scleral lens wear in 29 subjects.

RESULTS

Gland drop-out percentage was not statistically different between groups 1 and 2 (p = 0.464). Nevertheless, group 1 showed higher grey pixel intensity values than the other groups. Statistically significant correlations were found between gland visibility metrics and gland drop-out percentage. Repeatability was acceptable for all metrics, coefficient of variation achieving values between 0.52 and 3.18. While ocular symptoms decreased with scleral lens wear (p < 0.001), no statistically significant differences were found in gland drop-out percentage (p = 0.157) and gland visibility metrics (p > 0.217).

CONCLUSIONS

The proposed method can assess meibomian gland visibility in an objective and repeatable way. Scleral lens wear appears to not adversely affect meibomian gland drop-out and visibility while might improve dry eye symptoms after one year of lens wear. These preliminary results should be confirmed with a control group.

Topical review of the relationship between contact lens wear and meibomian gland dysfunction

Contact lens (CL) wearers often suffer from ocular discomfort, which leads to cessation of CL wear. About 30% to 50% of CL wearers complain of dry eye (DE) symptoms. Meibomian gland dysfunction (MGD) is considered the most common cause of evaporative DE. Numerous studies have investigated whether CL wear might affect the meibomian glands. This manuscript reviews studies examining the relationship between CL use and MGD. A PubMed database search was conducted for studies published between 1980-2021 with one or a combination of search terms related to "meibomian gland", "meibomian gland dysfunction", "contact lens", and/or "dry eye". Of the 115 papers reviewed, 22 articles were identified that examined the association between CL and MGD. Fifteen showed that CL wear affects the morphology and function of meibomian glands (MGs), while seven reported no significant impact of CL wear on MGs. This review provides an overview of these studies, emphasizing the diagnostic tests of MGD and conclusions. The review highlights the need for longitudinal prospective large cohort studies with control non- CL wearers to clarify the ambiguous relationship between MGD and CL wear, with special attention to varying CL material and wear times in order to identify the long-term impact of CLs on MG.

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.

Evaluation of tear parameters and meibomian gland morphology in keratoconus patients after epithelial-on corneal cross-linking

PURPOSE

To evaluate the variations in tear parameters and meibomian gland morphology after epithelial-on (epi-on) corneal collagen cross-linking (CXL) in keratoconus (KC) patients.

METHODS

This prospective observational study included 38 KC eyes that underwent epithelium-on CXL. Thirty-three eyes of 33 stable KC patients with no prior CXL treatment formed the KC group and 35 eyes of 35 healthy volunteers were recruited as the control group. All participants were evaluated by Schirmer I test, first and average noninvasive tear break-up time (NITBUT), ocular surface disease index (OSDI) questionnaire, and meibography scores. The CXL patients were evaluated preoperatively and at the 1st, 3rd, and 6th months, and participants without any intervention (KC and control groups) were evaluated initially, at 1st, 3rd, and 6th months.

RESULTS

The KC patients had significantly lower average NITBUT, higher OSDI scores, and impaired meibomian gland morphology than healthy individuals (NITBUT(seconds): KC, 12.8(2.4-17.6), healthy group (HG), 17.1(6.8-17.6); p = 0.012, OSDI: KC, 27.5(0.0-87.5), HG, 7.5(0.0-55.0); p < 0.001, p < 0.001, respectively). A significant difference was found in Schirmer values of the CXL group at 0-1st months, first NITBUT values at 1-6 months, and average NITBUT values at 1-3 and 1-6 months (p = 0.003, p = 0.001, p = 0.003, p = 0.001, respectively). All meibography parameters remained unchanged after CXL over a 6-month follow-up compared to initial measurements.

CONCLUSIONS

Even though the KC patients had lower NITBUT, higher OSDI scores, and increased meibomian gland disfunction, the CXL treatment did not significantly affect tear quantity, dry eye symptoms, and meibomian gland morphology.

Effect of Repeated Topical Povidone-Iodine and Antibiotic Applications on Meibomian Glands and Ocular Surface Parameters in Patients With Repeated Intravitreal Injections

OBJECTIVES

To assess whether meibomian glands and ocular surface parameters are affected by repeated topical povidone-iodine and antibiotic applications in patients with repeated intravitreal injections.

METHODS

Forty-five patients with at least three previous intravitreal injections and 28 healthy controls were included in the study. In the injection group, 21 patients had age-related macular degeneration and 24 patients had diabetic macular edema. For each participant, infrared meibography for the upper and lower eyelids and noninvasive tear break-up time calculation were performed with a corneal topographer. Fluorescein tear break-up time and ocular surface disease index (OSDI) scores were also obtained. Noninvasive tear break-up time, fluorescein tear break-up time, and OSDI scores were recorded for each participant and compared between the injection and control groups. These parameters were also compared as a subgroup analysis between patients with age-related macular degeneration (AMD) and diabetic macular edema (DME).

RESULTS

Upper lid meibomian gland loss, lower lid meibomian gland loss ratios, and OSDI scores were significantly higher in the intravitreal injection group compared with the control group (P=0.004, P<0.001, P<0.001, respectively). Fluorescein tear break-up time and noninvasive tear break-up time were significantly lower in the intravitreal injection group compared with the control group (P<0.001, P<0.001). There was no significant difference between the AMD and DME groups for these parameters.

CONCLUSION

This study showed for the first time that meibomian gland losses were significantly increased by repeated povidone-iodine and antibiotic applications in patients with repeated intravitreal injections. Ocular surface parameters were altered with higher ocular surface symptoms in those patients.

Dry Eye Symptoms in Individuals With Keratoconus Wearing Contact Lenses

OBJECTIVES

To assess dry eye symptoms associated with different contact lens modalities in patients with keratoconus using a dry eye questionnaire.

METHODS

An online survey was distributed by the National Keratoconus Foundation. The survey asked participants to report demographic characteristics, current optical correction, age at the time of diagnosis of keratoconus, and contact lens history. The 12-item Ocular Surface Disease Index (OSDI) questionnaire was also completed. Data from participants wearing the same contact lens modality bilaterally were analyzed.

RESULTS

The survey was completed by 197 individuals wearing the same contact lens modality bilaterally. The average age of participants at the time of the survey was 47.2±14.8 years (range: 15-87 years), and the average age at which keratoconus was diagnosed was 26.1±9.9 years (range: 8-55 years). The mean overall OSDI score of all participants was 40.2±22.8 (range: 0-100). There was no difference in the mean OSDI scores based on current contact lens modality type (F=1.79; n=187; P=0.13). Based on an OSDI score of 33 or higher, 90% of participants reported symptoms indicative of dry eye disease. Scleral lens wearers reported less discomfort on the individual items related to windy and low-humidity conditions.

CONCLUSIONS

Individuals with keratoconus, irrespective of contact lens modality, report a high incidence of dry eye symptoms.

PREVALENCE OF MEIBOMIAN GLAND DYSFUNCTION IN AFRICA: A SYSTEMATIC REVIEW AND META-ANALYSIS OF OBSERVATIONAL STUDIES

PURPOSE

To review and summarize information on meibomian gland dysfunction (MGD) epidemiology in Africa.

METHODS

A systematic search of online databases was conducted for literature/studies on MGD in Africa. Meta-analysis was conducted to estimate the prevalence of MGD in Africa. Meta-regression was used to explore sources of heterogeneity.

RESULTS

Twelve studies conducted in five countries were included in the review. All studies were hospital-based studies. Nine studies were included in the meta-analysis; the total sample size was 4963 and participants' age range was 17-96 years. The overall prevalence estimate of MGD in Africa was 45.9% (95% CI: 27.6-64.1%). Prevalence of MGD among males and females were each pooled from three studies and in urban and rural setting from 6 and 3 studies, respectively. Prevalence of MGD among males and females were 56.0% (95% CI: 22.4-89.5%) and 58.9% (95% CI: 28.5-89.4%) respectively; in urban and rural settings were 42.8% (95% CI: 21.1-64.5%) and 65.7% (95% CI: 25.7-95.7%), respectively. There was no association of MGD with sex (p = .872) and with study setting (p = .231).

CONCLUSION

There is a paucity of evidence on MGD prevalence in Africa, emphasizing the need for epidemiological studies to enhance our understanding of region-specific differences in MGD in Africa. The pooled estimate from hospital-based studies, however, suggests a substantial MGD burden in Africa. Epidemiological studies are needed to assess if this translates to a high disease burden within the general African population.

Clinical evaluation of meibomian gland dysfunction in patients with keratoconus

PURPOSE

To investigate the association of keratoconus (KC) with meibomian gland dysfunction (MGD) and to describe the epidemiological characteristics of MGD in this disease.

METHODS

In this observational study, 120 KC patients seen in the Department of Ophthalmology of the Complexo Hospitalario Universitario de Santiago de Compostela and 87 controls were analyzed. The Ocular surface disease index (OSDI) questionnaire was administered and several DED tests and an evaluation of the meibomian glands and lid margin were performed. MGD signs and DED tests were compared between the groups. Symptoms were further analyzed in patients and controls with and without MGD.

RESULTS

KC was significantly associated with MGD after adjusting for age and sex [adjusted odds ratio (ORa), 2.40]. The frequency of MGD in KC patients [59 (49.2%) KC patients and 25 (28.7%) controls had MGD] correlated with the severity of KC (r = 0.206) (P = 0.020). Mean OSDI score in KC patients with and without MGD was 31.1 ± 24.1 and 35.2 ± 26.0 (P = 0.326), and 17.2 ± 22.7 and 13.3 ± 14.1 in controls with and without it (P = 0.366). The most common MGD signs coincided in both groups. Staining with fluorescein (P = 0.000) and lissamine green (P = 0.019) was higher in KC patients, but no differences were detected with TBUT (P = 0.116) or the Schirmer test (P = 0.637). Hypersecretory MGD was the most prevalent variant in both groups.

CONCLUSIONS

MGD and DED are common in KC patients. MGD correlates with the severity of KC and is indistinguishable from MGD in patients without KC. No association was found with symptoms. Patients with KC should be screened for MGD because of its possible clinical implications. Further research is needed to clarify the role of MGD in KC patients.