Dry Eye Group Research Articles

Repeatability of Scheimpflug-Placido camera in mild dry eye versus normal eyes according to the topographical position of the cornea.

We aimed to investigate the repeatability of various corneal measurements according to topographical location in the entire cornea measured by dual rotating Scheimpflug-Placido camera and to explore the differences in repeatability between patients with mild dry eye and those with normal eyes. In both the normal and dry eye groups, divided based on BUT or the height of the tear film, there were no statistically significant differences in the ratio of unacceptable variation (RUV) and ICC. The consistency of the examination of the anterior and posterior refractive values and corneal thickness according to the corneal location, measured three times repeatedly using the Galilei anterior segment camera, was high. There was no difference based on the height of the tear film or the tear film break-up time. However, caution is needed when interpreting the values of the anterior corneal refractive values, as there can be changes of more than 0.5D within 3mm of the central area.

MUC1‑ND interacts with TRPV1 to promote corneal epithelial cell proliferation in diabetic dry eye mice by partly activating the AKT signaling pathway.

Although both mucin1 (MUC1) and transient receptor potential cation channel subfamily V member 1 (TRPV1) have been reported to be associated with dry eye (DE) disease, whether they interact and their regulatory roles in diabetic DE disease are unknown. Diabetic DE model mice were generated by streptozotocin induction and assessed by corneal fluorescein staining, tear ferning (TF) tests, phenol red thread tests, hematoxylin and eosin staining of corneal sections and periodic acid Schiff staining of conjunctival sections. Cell proliferation was measured by CCK8 assay. Western blotting was performed to measure protein expression. Primary mouse corneal epithelial cells (MCECs) were cultured after enzymatic digestion. Immunofluorescence staining of MCECs and frozen corneal sections was conducted to assess protein expression and colocalization. Coimmunoprecipitation was performed to detect protein‑protein interactions. It was found that, compared with control mice, diabetic DE mice exhibited increased corneal epithelial defects, reduced tear production, poorer TF pattern grades and impaired corneal and conjunctival tissues. In vivo and in vitro experiments showed that hyperglycemia impaired cell proliferation, accompanied by decreased levels of the MUC1 extracellular domain (MUC1‑ND) and TRPV1. Additionally, it was found that capsazepine (a TRPV1 antagonist) inhibited the proliferation of MCECs. Notably, MUC1‑ND was shown to interact with the TRPV1 protein in the control group but not in the diabetic DE group. It was also found that the AKT signaling pathway was attenuated in the diabetic DE mice and downstream of TRPV1. MUC1‑ND interacted with TRPV1, partly activating the AKT signaling pathway to promote MCEC proliferation. The present study found that the interaction of MUC1‑ND with TRPV1 promotes MCEC proliferation by partly activating the AKT signaling pathway, providing new insight into the pathogenesis of corneal epithelial dysfunction in diabetic DE disease.

Psychometric validation of the Chinese version of the dry eye-related quality-of-life score questionnaire.

To psychometrically validate the Chinese version of the dry eye-related quality-of-life score questionnaire (DEQS-CHN) among Chinese patients with dry eye. This study involved 231 participants, including 191 with dry eye disease (DED) comprising the dry eye disease group, and 40 healthy participants forming the control group. Participants were required to complete the DEQS-CHN, and Chinese dry eye questionnaire and undergo clinical tests including the fluorescein breakup time (FBUT), corneal fluorescein staining (CFS), and Schirmer I test. To assess the internal consistency and retest reliability, Cronbach's α and the intraclass correlation coefficient (ICC) were employed. Content validity was assessed by item-level content validity index (ICV) and an average scale-level content validity index (S-CVI/Ave). Construct validity was assessed by confirmatory factor analysis. The concurrent validity was assessed by calculating correlations between DEQS-CHN and Chinese dry eye questionnaire. Discriminative validity was evaluated through non-parametric tests, with receiver operating characteristic (ROC) curve serving as conclusive indicators of the questionnaire's distinguishing capability. The Cronbach's α coefficients for frequency and degree of ocular symptoms, impact on daily life, and summary score were 0.736, 0.704, 0.811, 0.818, 0.861, and 0.860, respectively, and the ICC were 0.611, 0.677, 0.715, 0.769, 0.711, and 0.779, respectively. All I-CVI scores ranged from 0.833 to 1.000, with an S-CVI/Ave of 0.956. Confirmatory factor analysis results exhibited a well-fitting model consistent with the original questionnaire [χ 2/df=2.653, incremental fit index (IFI)=0.924, comparative fit index (CFI)=0.924, Tucker-Lewis index (TLI)=0.909, and root mean square error of approximation (RMSEA)=0.065]. There was a moderate positive correlation between the DEQS-CHN and the Chinese dry eye questionnaire (r 2=0.588). The dry eye group demonstrated significantly higher scores compared to the control group, and the area under the curve (AUC) value was 0.8092. The DEQS-CHN has been demonstrated as a valid and reliable instrument for assessing the impact of dry eye disease on the quality of life among Chinese individuals with DED.

Effect of posterior chamber phakic refractive lens implantation on the ocular surface and tear film

To evaluate changes in dry eye-related parameters after posterior chamber phakic refractive lens (PC-PRL) implantation. This prospective study included 21 highly myopic patients (39 eyes) who underwent PC-PRL implantation at Lanzhou Huaxia Eye Hospital between January 2021 and June 2022, with a 3-month postoperative follow-up. In addition to routine preoperative examinations, dry eye assessments were conducted preoperatively and at 1 week, 1 month, and 3 months postoperatively. These assessments included the Ocular Surface Disease Index (OSDI) questionnaire score, non-invasive first tear break-up time (NIF-BUT), non-invasive average tear break-up time (NIA-BUT), tear meniscus height (TMH), meibomian gland loss (MGL) rate, and Schirmer I test (SIt). Repeated measures ANOVA was used to compare the differences in parameters across different time points, with pairwise comparisons conducted using the LSD-t test. After grouping, the Student's t-test was applied to compare normally distributed data, while the Mann–Whitney U test was used for non-normally distributed data. Categorical data were analyzed using the chi-square test. A total of 21 patients (39 eyes) were included, comprising 10 males (19 eyes) and 11 females (20 eyes), aged 19 to 49 years (33.76 ± 7.87). All patients completed the 3-month follow-up. Significant differences in OSDI scores were observed pre- and post-surgery (P = 0.008), with a peak at one week post-surgery (P < 0.001), then stabilizing at one and three months post-surgery. Postoperative NIF-BUT and NIA-BUT significantly decreased (P < 0.001 for both) but returned to preoperative levels within three months. There were no significant changes in TMH, MGL, or SIt postoperatively (P > 0.05). Significant differences in dry eye parameters were observed between the dry eye and control groups before and after surgery (P < 0.001). PC-PRL implantation impacts tear film stability on the ocular surface after surgery, leading to varying degrees of dry eye symptoms in patients. After surgery, all dry eye parameters return to their preoperative levels within three months.

Development of a dry eye index as a new biomarker of dry eye disease.

To evaluate signs and symptoms in patients diagnosed with dry eye disease (DED), divided into dry eye (DE) groups, in order to find a new biomarker that allows an accurate diagnosis, management and classification of DED. This cross-sectional, observational study included 71 DED subjects. Subjective symptoms, visual quality and DE signs were assessed using the Ocular Surface Disease Index (OSDI), the Quality of Vision (QoV) questionnaire, best corrected distance visual acuity (VA), functional visual acuity (FVA), contrast sensitivity (CS), high- and low-order corneal aberrations (HOA and LOA, respectively), tear break-up time (TBUT), Meibomian Gland Dysfunction (MGD), Schirmer test, corneal staining, lid wiper epitheliopathy (LWE) and meibography. Participants were classified into three groups based on dryness severity using a cluster analysis, i.e., mild (N = 17, 55.8 ± 15.4 years), moderate (N = 41, 63.5 ± 10.6 years) and severe (N = 13, 65.0 ± 12.0). A new Dry Eye Severity Index (DESI) based on ocular surface signs has been developed and its association with symptoms, visual quality and signs was assessed. Comparisons between groups were made using Kruskal-Wallis and Chi-squared tests. Spearman correlation analysis was also performed. The DESI was based on three tests for DE signs: TBUT, Schirmer test and MGD. The DESI showed significant differences between different pairs of groups: Mild Dryness versus Moderate Dryness (p < 0.001), Mild Dryness versus Severe Dryness (p < 0.001) and Moderate Dryness versus Severe Dryness (p < 0.001). The DESI was significantly correlated with age (rho = -0.30; p = 0.01), OSDI score (rho = -0.32; p = 0.007), QoV score (rho = -0.35; p = 0.003), VA (rho = -0.34; p = 0.003), FVA (rho = -0.38; p = 0.001) and CS (rho = 0.42; p < 0.001) Also, significant differences between the severity groups were found for OSDI and QoV scores, VA, FVA, CS and MGD (p < 0.05). The DESI has good performance as a biomarker for the diagnosis, classification and management of DED.

Clinical ocular surface characteristics and expression of MUC5AC in diabetics: a population-based study.

To investigate the clinical characteristics and the expression of mucin 5AC (MUC5AC) in in diabetic and non-diabetic subjects with or without dry eye disease. A total of 399 participants (796 eyes) aged 50-80 years were enrolled in this study. Participants were divided into 4 groups: non-diabetic without dry eye group (normal group), non-diabetic with dry eye group, diabetic without dry eye group and diabetic with dry eye group. Demographic information, fasting plasma glucose (FBG), and glycated haemoglobin A1C (HbA1C) data were collected. Additionally, ocular surface disease index (OSDI) questionnaire, signs of dry eye, tear osmolarity, and meibomian glands were evaluated. Tear MUC5AC expression and conjunctival goblet cells density (GCD) were tested. Compared with non-diabetic with dry eye group, diabetic with dry eye group showed significantly lower tear film osmolarity (TFO), but higher corneal fluorescein and conjunctival lissamine green staining scores. In comparison with diabetic without dry eye group, diabetic with dry eye group showed significantly higher TFO, corneal fluorescein and conjunctival lissamine green staining scorers. The MUC5AC concentration and GCD of diabetic with dry eye group was significantly lower than those of the non-diabetic with dry eye group. Diabetic subjects with higher HbA1c levels (≥7.8%) showed higher TFO and shorter fluorescein tear break time. Diabetics with dry eye exhibited notably higher corneal fluorescein and conjunctival lissamine green staining scores. Conjunctival goblet cells and MUC5AC were significantly reduced in diabetics. Higher TFO was associated with the duration of diabetes and HbA1c levels.

Evaluating the Efficacy of the Diluted Schirmer Method for Tear Collection in Dry Eye Syndrome Patients

Purpose This study assesses the diluted Schirmer method’s effectiveness in collecting tears from dry eye syndrome patients, aiming to identify the most suitable tear collection technique for them. Methods A prospective study. Tear samples were collected from patients with dry eye syndrome and healthy individuals using two methods: (1) Direct Schirmer Method: Schirmer strips were directly inserted into the eye to collect tears. (2) Diluted Schirmer Method: After instilling physiological saline into the eye and waiting for 30 s to ensure thorough mixing with tears, Schirmer strips were used for collection. Tear samples from both groups were analyzed and compared for total protein and cytokine levels (IL-1β, IL-6, IL-8, TNF-α). Results (1) The study included 32 participants: 16 with dry eye syndrome (4 males, 12 females, average age 34.92 ± 10.13 years) and 16 healthy controls (5 males, 11 females, average age 32.25 ± 9.87 years). (2) The diluted Schirmer method produced a significantly larger tear volume compared to the direct method (p < 0.05), with lower Visual Analogue Scale (VAS) scores indicating less discomfort (p < 0.05). (3) The average total protein content of the two groups was 51.70 ± 3.166 ng measured by Direct Schirmer method, and the average total protein content of the Diluted Schirmer method was 50.05 ± 3.263 ng. There was no statistical difference between the two groups. (t = 1.051, p = 0.3098) (4) The concentrations of total tear protein and various cytokines measured by both methods were higher in the dry eye group compared to the normal group, with statistically significant differences (p < 0.05). Both methods reflected consistent changes in tear protein profiles. Conclusion The diluted Schirmer method can comfortably collect an adequate volume of tear samples in a short time and consistently reflect changes in tear proteins, making it an effective method for tear collection in patients with dry eye syndrome.

Ocular surface changes in moderate-to-severe acne vulgaris.

To investigate ocular surface disorders and tear function changes in patients with acne vulgaris and explore the potential relationship between acne vulgaris and dry eye. This cross-sectional study included right eyes of 53 patients with acne vulgaris and 54 healthy controls. The participants completed the Ocular Surface Disease Index (OSDI) questionnaire. The following ocular surface-related parameters were measured: tear meniscus height (TMH), noninvasive tear breakup time (NIBUT), Schirmer I test (SIT), lipid layer thickness (LLT) score of the tear film, meibum score, meibomian gland orifice obstruction score, the ratio of meibomian gland loss, conjunctival hyperemia score, and corneal fluorescein staining (CFS) score. The stability of the tear film decreased in acne vulgaris patients. In the acne group, the TMH and NIBUT were lower, whereas the OSDI, meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss, and conjunctival hyperemia score were higher compared with controls (P<0.05). There were no significant differences in the CFS score, SIT, or LLT score between the groups (P>0.05). In two dry eye groups, the TMH, NIBUT, and LLT score were lower in the acne with dry eye (acne-DE) group, and the meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss and conjunctival hyperemia score in the acne-DE group were higher (P<0.05). There were no significant differences between OSDI, SIT, and CFS score (P>0.05). Patients with moderate-to-severe acne vulgaris are more likely to experience dry eye than those without acne vulgaris. Reduced tear film stability and meibomian gland structure dysfunction are more pronounced in patients with moderate-to-severe acne and dry eye.

Inflammation due to ocular surface homeostasis imbalance caused by pterygia: tear lymphotoxin-alpha study and a literature review

ObjectiveTo estimate the pterygium ocular surface state, and compare with healthy eyes and dry eyes. To investigate the inflammation due to pterygia growth by tear Lymphotoxin-alpha (LT α) test.DesignProspective, single-center study.Participants400 patients, divided into 100 pterygium group, 100 mild dry eye group, 100 moderate dry eye group, and 100 age-and sex-matched normal controls.MethodsThe non-invasive break-up time (NIBUT), tear meniscus height (TMH) test, corneal fluorescein staining (CFS), meibomian gland loss score (MGs), and lipid layer thickness (LLT) were evaluated in all patients. Pterygium status and ocular status in the pterygium group were collected. The tear LT α test was conducted in the pterygium patients group.ResultPterygium can affect the ocular surface, leading to decreased tear film stability. The TMH, NIBUT, CFS, MGs, and lipid layer thickness can provide insights into this phenomenon. The presence of pterygium can change the structure and condition of the ocular surface. Tear LT α testing shows an abnormal decrease in LT α levels in pterygium patients. This indicates an immune-inflammation microenvironment that causes tissue repair deficiency.ConclusionThe dry eye triggered by the growth of pterygium may originate from the tear film instability due to pterygia. As an inflammatory index, LT α in the development of pterygium and the aggravation of dry eye patients can indicate that the ocular surface is in different inflammatory states. Future tear testing in LT α may be a potential indicator to assess the inflammatory status of the dry eye.

Central corneal thickness in new cases of dry eyes: A case-control study

Significance Loss of homeostasis and chronic inflammation result in ocular surface damage in dry eyes, which is also associated with corneal thinning in established cases. Yet, the correlation between corneal thickness and new cases of dry eyes remains inadequately supported by evidence. Purpose This study aimed to compare the central corneal thickness of new cases of dry eyes to that of age- and gender-matched controls. Methods A total of 45 dry eye patients were compared with 61 age- and gender-matched non–dry eye individuals. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms, and the central corneal thickness was measured with a Nidek CEM-530 specular microscope. Patients were grouped based on disease severity (OSDI scores), and the clinical findings were compared between groups for slit-lamp examinations, Schirmer's I test, and tear film breakup time. Results The median age of patients was 25.0 (interquartile range [IQR], 20.0 to 32.0) and 27.0 (IQR, 20.0 to 32.0) years in the control and dry eye groups, respectively (p=0.63). The median (IQR) values of the OSDI scores, tear film breakup time scores, and Schirmer's test measurements in the control groups were 10.4 (8.3 to 10.4), 12.0 (11.0 to 14.0) seconds, and 16.0 (13.5 to 19.5) mm, respectively, which differed from the dry eye groups (p&lt;0.0001). These values in the dry eye group were 29.1 (25.0 to 39.5), 4.0 (3.0 to 8.0) seconds, and 8.0 (3.5 to 11.0) mm, respectively. Patients with dry eyes had lower central corneal thickness than controls (p&lt;0.01). The mean ± standard deviation central corneal thicknesses in patients with dry eyes and the control group were 520.3 ± 26.8 and 545.3 ± 18.8 μm, respectively. Conclusions The central corneal thickness in dry eyes was significantly reduced compared with the control group. These findings may be useful in monitoring and managing dry eyes and should be considered in intraocular pressure measurements and refractive surgical procedures.

Assessment of tear film parameters post-treatment with commercial eyelid cleaning wipes: a pilot study.

To investigate the short-term effects of commercially available eyelid-cleaning wipes on film parameters. This study enrolled 48 healthy participants aged 20-35y (both males and females). Clinical assessment included the Ocular Surface Disease Index (OSDI) questionnaire, non-invasive tear break-up time (NITBUT), tear meniscus height (TMH), and lipid layer pattern (LLP). Based on these initial results, participants were categorized as either non-dry eye or dry eye. Participants in each group were randomly allocated to either Blephaclean® or Systane® treatments. Changes in NITBUT, TMH, and LLP levels before and after lid wipe treatment were assessed. The dry eye group exhibited significantly higher OSDI scores and lower NITBUT and TMH levels than in the non-dry eye group (P<0.001). Following the application of eyelid wipes (Systane® wipes), dry eye subjects experienced a significant improvement in NITBUT levels (P=0.0014) compared to the non-dry eye individuals. Although the remaining participants showed a marginal increase in TMH and NITBUT levels, these changes did not achieve statistical significance (P>0.05). Similarly, the LLP levels were significantly improved with Systane® (P<0.001) post-treatment compared to individuals in the non-dry eye group. However, the dry eye subjects showed higher post-treatment LLP levels than the untreated group (P<0.02). The short-term effects of Systane® eyelid wipes on tear film parameters suggest their effectiveness in dry eye disease. Nonetheless, further exploration of their long-term impact is essential to justify their cost effectiveness and efficacy in treating both aqueous deficiency and evaporative dryness.

Unique composition of ocular surface microbiome in the old patients with dry eye and diabetes mellitus in a community from Shanghai, China

BackgroundThis study investigates the variations in microbiome abundance and diversity on the ocular surfaces of diabetic patients suffering from dry eye within a community setting. The goal is to offer theoretical insights for the community-level prevention and treatment of dry eye in diabetic cohorts.MethodsDry eye screening was performed in the Shanghai Cohort Study of Diabetic Eye Disease (SCODE) from July 15, 2021, to August 15, 2021, in the Xingjing community; this study included both a population with diabetes and a normal population. The population with diabetes included a dry eye group (DM-DE, n = 40) and a non-dry eye group (DM-NoDE, n = 39). The normal population included a dry eye group (NoDM-DE, n = 40) and a control group (control, n = 39). High-throughput sequencing of the 16 S rRNA V3-V4 region was performed on conjunctival swab from both eyes of each subject, and the composition of microbiome on the ocular surface of each group was analyzed.ResultsSignificant statistical differences were observed in both α and β diversity of the ocular surface microbiome among the diabetic dry eye, diabetic non-dry eye, non-diabetic dry eye, and normal control groups (P < 0.05).ConclusionsThe study revealed distinct microecological compositions on the ocular surfaces between the diabetic dry eye group and other studied groups. Firmicutes and Anoxybacillus were unique bacterial phyla and genera in the dry eye with DM group, while Actinobacteria and Corynebacterium were unique bacterial phyla and genera in the normal control group.

Effect of phospholipid‐eluting contact lens on dry eye in rabbit

Aims/Purpose: To investigate the effects of new phosphatidylcholine‐eluting contact lenses (PC‐CL) on dry eye in Rabbit.Methods: 18 New Zealand rabbits were used in this study. Meibomian gland orifices were electrocauterized in the dry eye group. PC‐CL were provided from Neo Vision (Yongin, Korea). Rabbits were fitted with control contact lens on one eye and 0.1% PC‐CL on the other eye or with 0.1% PC‐CL on one eye and 0.3% PC‐CL on the other eye. Tear break‐up time (TBUT), tear osmolarity, and corneal fluorescein staining score (FSS), central corneal thickness (CCT), and conjunctival histology were evaluated.Results: In both dry eye and non‐dry eye group, TBUT was longer and tear osmolarity was lower in 0.1% PC‐CL compared to control lens. Cornea was stained with fluorescein in dry eye group, but not in non‐dry eye group. CCT showed no difference in PC‐CL and control lens on both dry eye and non‐dry eye group. In dry eye group, goblet cell density tended to be slightly higher in PC‐CL compared to control. There was no significant difference in TBUT, tear osmolarity, CCT, FSS, and goblet cell density between 0.1% PC‐CL and 0.3% PC‐CL.Conclusions: PC‐CL stabilized tear film and lowered tear osmolarity in dry eye. Thus, it may reduce dry eye symptoms and contact lens complications in clinical practice.

Ocular surface microbiota in patients with varying degrees of dry eye severity.

To elucidate the profiles of commensal bacteria on the ocular surfaces of patients with varying severity of dry eye (DE). The single-center, prospective, case-control, observational study categorized all participants into three distinct groups: 1) control group (n=61), 2) mild DE group (n=56), and 3) moderate-to-severe DE group (n=82). Schirmer's tear secretion strips were used, and the bacterial microbiota was analyzed using 16S ribosomal ribonucleic acid gene sequencing. The three groups had significant differences in alpha diversity: the control group had the highest richness (Chao1, Faith's phylogenetic diversity), the mild DE group showed the highest diversity (Shannon, Simpson), and the moderate-to-severe DE group had the lowest of the above-mentioned indices. DE severity was positively correlated with a reduction in beta diversity of the microbial community, with the moderate-to-severe DE group exhibiting the lowest beta diversity. Linear discriminant analysis effect size presented distinct dominant taxa that significantly differed between each. Furthermore, the exacerbation of DE corresponded with the enrichment of certain pathogenic bacteria, as determined by random forest analysis. As DE severity worsens, microbial community diversity tends to decrease. DE development corresponds with changes in microbial constituents, primarily characterized by reduced microbial diversity and a more homogenous species composition.

Effects of diquafosol sodium in povidone iodine-induced dry eye model.

To investigate the effects of diquafosol sodium (DQS) for dry eye model induced with povidone-iodine (PI) solution. Ten Sprague Dawley rats as the control group. Thirty Sprague Dawley rats were used to establish the dry eye model with stimulation of 10 g/L PI for 14d, then divided rats into three groups: dry eye group with no treatment (DED group, n=10); phosphate buffer saline treated group (PBS group, n=10); diquafosol treated group (DQS group, n=10). Clinical changes were observed by tear production test, fluorescein staining, tear break-up time (TBUT) test, corneal confocal microscope and ocular surface comprehensive analyzer. Eyeballs were collected on day 10 of treatment for hematoxylin-eosin (HE), periodic acid-Schiff (PAS), and alcian blue staining. TUNEL assay, polymorphonuclear (PMN) and mucin 1 (MUC1) immunofluorescence were performed and corneal ultrastructural changes were detected by electron microscopy. Compared with DED and PBS groups, tear production (7.26±0.440 vs 4.07±0.474 mm; 7.26±0.440 vs 3.74±0.280 mm; all P<0.01) and TBUT (7.37±0.383s vs 1.49±0.260s; 7.37±0.383s vs 1.42±0.437s; all P<0.01) were significantly increased in DQS group. HE, PAS, and alcian blue staining and MUC1 immunofluorescence showed mucins and conjunctival goblet cells density (8.45±0.718 vs 5.21±0.813 cells/0.1 mm2; 8.45±0.718 vs 5.36±0.615 cells/0.1 mm2; all P<0.01) increased in DQS group. Confocal microscopy, PMN immunofluorescence and TUNEL staining showed inflammatory infiltration and corneal epithelial cells apoptosis decreased in DQS group. The increased number of microvilli in corneal epithelial and the recovered cell junction were observed in DQS group. PI instillation can induce goblet cells and mucin loss, epithelial cell apoptosis and inflammation, which are consistent with the pathological manifestations of dry eye. Diquafosol can repair the ocular surface damage caused by PI, reduce corneal inflammation, inhibit corneal epithelial cell apoptosis, promote mucin secretion and maintain tear film stability.

Relation Between Corneal Dendritic Cell Density and Tear Film Stability in Patients with Epidemic Keratoconjunctivitis Associated Dry Eye

Purpose To clarify the ocular surface features of patients with recent history of epidemic keratoconjunctivitis (EKC) and the relation between corneal dendritic cells (DCs) and ocular discomfort. Methods Normal controls (NC) and dry eye (DE) patients without EKC were recruited. Patients with recent EKC history (onset >4 weeks, but <20 weeks) were recruited as EKC + DE group (with dry eye) or EKC–DE group (without dry eye). Ocular surface disease index (OSDI) questionnaire, tear film parameters including lipid layer thickness, first tear break-up time (fBUT), average tear break-up time (aBUT), tear meniscus height and Schirmer I test, meibomian gland parameters, and in vivo corneal confocal microscopy were evaluated. Results 50 subjects in the NC group, 83 patients in the DE group, 76 patients in the EKC + DE group, and 38 patients in the EKC–DE group were included. Compared with the NC, DE, and EKC–DE groups, the EKC + DE group represented higher OSDI, lid margin, and meibum score (p < 0.05). In the EKC + DE group, the tear volume (10.5 ± 3.7 mm) was significantly higher than in the DE group (8.1 ± 2.8 mm, p < 0.001). The DC density in the EKC + DE group (29.98 ± 15.38 cells/image) was significantly higher than in NC, DE, and EKC–DE groups (4.68 ± 4.05 cells/image) (p < 0.001). The DC density was positively correlated with OSDI, lid margin, and meibum score (all p < 0.01) while inversely correlated with fBUT, aBUT (all p < 0.001) in the EKC + DE group. Conclusions Corneal DC density significantly correlates to ocular discomfort and tear film instability in patients with recent EKC history who suffer from DE without aqueous tear deficiency.

Effect of dry eye on the reliability of keratometry for cataract surgery planning

This study aimed to evaluate the effects of dry eye on the reproducibility of keratometry (K) measurements in patients presenting for cataract surgery. A non-randomized controlled clinical study was performed. Eighty-three eyes of eighty-three patients with cataracts who were enrolled in our hospital from March 2020 to July 2020 were studied. The mean non-invasive tear film break-up time (NIBUT), corneal fluorescein staining score, and ocular surface disease (OSD) SPEED II questionnaire were measured and recorded prior to surgery, and the patients were assigned to a "dry eye" group (n=35) or a "non-dry eye" group (n=48). The K of the patients was measured twice by a Tomey OA-2000 (an average of three times each). The difference of the mean K (ΔKm) and astigmatism vector (ΔKvector) between the two measurements was calculated. The ΔKm and ΔKvector between the two groups were compared. The relationship between the measurement parameters of dry eyes and the accuracy of the preoperative K values was analyzed. ΔKm was 0.09 D [0.03; 0.19] in the non-dry eye control group and 0.28 D [0.18; 0.50] in the dry eye group, with a statistical difference between the two groups (P=0.005). The ΔKvector of the non-dry eye control group was 0.22 D [0.14; 0.42], and that of the dry eye group was 0.50 D [0.28; 1.06]. There was a significant difference between the two groups (P=0.010). Between the two groups, the percentage of the ΔKm and ΔKvector values greater than 0.5 D were statistically different (P<0.05). There was no significant difference in ΔKm between the groups with NIBUT>5s and NIBUT≤5s (P=0.537). There was no significant difference in ΔKm between groups≥2 and<2 on the OSD SPEED II questionnaire scores (P=0.442). Dry eye can affect the reliability of keratometry measurements before cataract surgery, thereby affecting the accuracy of intraocular lens power calculations. In cataract surgery planning, it is necessary to detect subjective and objective indicators of dry eye in patients and carry out effective intervention so as to avoid refractive errors caused by inaccurate keratometry measurements.

Metagenomic analysis of microbiological changes on the ocular surface of diabetic children and adolescents with a dry eye

BackgroundMicrobiome changes on the ocular surface may cause dry eyes. A metagenome assay was used to compare the microbiome composition and function of the ocular surface between diabetic children and adolescents with dry eye, diabetic children and adolescents without dry eye, and normal children.Materials and methodsTwenty children and adolescents aged 8 to 16 with diabetes were selected from the Shanghai Children and Adolescent Diabetes Eye Study. Ten healthy children and adolescents belonging to the same age group were selected from the outpatient clinic during the same period. The participants were classified into the dry eye group (DM-DE group, n = 10), the non-dry eye group (DM-NDE group, n = 10) and the normal group (NDM group, n = 10). A conjunctival sac swab was collected for metagenomic sequencing, and the relationship between the microbiome composition and functional gene differences on the ocular surface with dry eye was studied.ResultsThe classification composition and metabolic function of the microorganisms on the ocular surface of children in the 3 groups were analyzed. It was found that children’s ocular microbiota was composed of bacteria, viruses and fungi. There were significant differences in α diversity and β diversity of microbial composition of ocular surface between DM-DE group and NDM group(P<0.05). There were significant differences in α and β diversity of metabolic pathways between the two groups(P<0.05). The functional pathways of ocular surface microorganisms in diabetic children with dry eyes were mainly derived from human disease, antibiotic resistance genes, carbohydrate, coenzyme and lipid transport and metabolism-related functional genes; In normal children, the functional pathways were mainly derived from replication, recombination, repair, signal transduction and defense-related functional genes.ConclusionThe DM-DE group have unique microbial composition and functional metabolic pathways. The dominant species and unique metabolic pathways of the ocular surface in the DM-DE group may be involved in the pathogenesis of dry eye in diabetic children.

Morphological changes in the meibomian gland in children with tic disorders.

Since blinking accelerates meibomian gland (MG) expression, abnormal blinking in children with tic disorders may be associated with the morphological changes of the MGs. Our study aimed to quantitively evaluate the morphology of the MG in these children. In this prospective case-control study, we examined 68 eyes of 68 children with tic disorders, 47 eyes of 47 children with dry eye, and 45 eyes of 45 healthy children at the Hangzhou Branch of the Eye Hospital of Wenzhou Medical University from October 2020 to March 2021. We used an Oculus Keratograph 5M (K5M) to capture the MG images, noninvasive breakup time (NIBUT), and tear meniscus height (TMH). An automated method was used to analyze MG length, width, area, gland diameter deformation index (DI), and gland signal index (SI). Parameters across the three groups were assessed using Kruskal-Wallis test followed by Mann-Whitney test with Bonferroni correction for multiple comparisons. The eyes in the tic disorders group exhibited lower MG length and area values compared with those of the other groups (all P values <0.001) and lower MG width values compared with those of children in the dry eye group (P=0.009). The tic disorder and dry eye groups both had a larger percentage of eyes with a U-shaped MG duct when compared with the control group (P<0.001 and P=0.017). The dry eye group had the lowest TMH and NIBUT values (both P values <0.001). The NIBUT values in the tic disorder group were lower than those in the control group (P<0.001). No significant correlations were detected between clinical tests and MG morphology in any of the groups. Blinking disorders have a significant impact on MG morphology. In children with tic disorders, more attention should be devoted to monitoring the MG over time.

Ocular microbiome changes in dry eye disease and meibomian gland dysfunction

The most common and chronic ocular problem of aging is dry eye disease (DED) and the associated condition of meibomian gland dysfunction (MGD). The resident ocular surface bacteria may have a role in maintaining homeostasis and perturbation may contribute to disease development. The aim of this study was to compare the microbiomes of the conjunctiva and eyelid margin in humans with mild and moderate DED and controls using 16 S rRNA gene sequencing. The conjunctiva and lid margin of three cohorts (N = 60; MGD, MGD with lacrimal dysfunction [MGD + LD] and controls) were swabbed bilaterally three times over three months. Microbial communities were analysed by extracting DNA and sequencing the V3–V4 region of the 16 S ribosomal RNA gene using the Illumina MiSeq platform. Sequences were quality filtered, clustered into amplicon sequence variants (ASVs) using UNOISE algorithm and taxonomically classified using a Bayesian Last Common Ancestor (BCLA) algorithm against the GTDB 2207 database. The overall microbial communities of the MGD, MGD + LD and control groups were significantly different from each other (P = 0.001). The MGD and MGD + LD dry eye groups showed greater variability between individuals compared to the control (PERMDISP, P < 0.01). There was decreased richness and diversity in females compared to males for the conjunctiva (P < 0.04) and eyelid margin (P < 0.018). The conjunctiva in the MGD + LD group had more abundant Pseudomonas azotoformans, P. oleovorans and Caballeronia zhejiangensis compared to MGD and control (P < 0.05), while the MGD group had more abundant Corynebacterium macginleyi and C. kroppenstedtii compared to control (P < 0.05). The lid margin in MGD was more abundant in C. macginleyi, C. accolens, and C. simulans compared to the MGD + LD and control (P < 0.05). There were differences in the overall microbial community composition and certain taxa, including increased levels of lipophilic bacteria, on the conjunctiva and eyelid margin in mild to moderate DED/MGD compared to controls. DED/MGD was also associated with a reduced bacterial richness and diversity in females.