Tear Meniscus and Corneal Sub-basal Nerve Plexus Assessment in Primary Sjögren Syndrome and Sicca Syndrome Patients

Skin-Only Versus Skin-Plus-Orbicularis Resection Blepharoplasty: An Elaborated Analysis of Early- and Long-Term Effects on Corneal Nerves, Meibomian Glands, Dry Eye Parameters, and Eyebrow Position

PURPOSE

To evaluate the early- and long-term effects of 2 different blepharoplasty techniques on corneal nerves, meibomian gland morphology, clinical parameters of dry eye disease (DED), and eyebrow position.

METHODS

This prospective, interventional study included age-sex-matched blepharoplasty patients who had a skin-only resection (24 eyes of 12 patients; Group-S) or a skin-plus-orbicularis muscle resection (24 eyes of 12 patients; Group-M) procedure. Preoperative and postoperative parameters of in vivo corneal confocal microscopy (IVCCM; corneal nerve fiber density [CNFD], nerve branch density [CNBD], and nerve fiber length), meibomian gland area loss (MGAL), DED (Schirmer I test and noninvasive tear breakup time), and eyebrow heights (lateral [LBH] and central [CBH]) were evaluated and compared between the intervention groups ( ClinicalTrials.gov , NCT05528016).

RESULTS

Compared with baseline, the CNBD of Group-S (19.91 ± 7.66 vs. 16.05 ± 7.28 branches/mm 2 , p = 0.049) and CNFD of Group-M (19.52 ± 7.45 vs. 16.80 ± 6.95 fibers/mm 2 , p = 0.028) was significantly decreased at postoperative first week. However, in both groups, IVCCM parameters returned to baseline values at postoperative first month and first year ( p > 0.05). A significant MGAL increase was observed in Group-S (18.47 ± 5.43 vs. 19.94 ± 5.31, p = 0.030) and Group-M (18.86 ± 7.06 vs. 20.12 ± 7.01, p = 0.023) at the postoperative first year, demonstrating meibomian gland atrophy. Only significant changes were observed in Group-M in LBH (16.17 ± 2.45 vs. 16.67 ± 2.28 mm, p = 0.044) and CBH (17.33 ± 2.35 vs. 17.96 ± 2.31 mm, p = 0.004) at postoperative first year.

CONCLUSIONS

Blepharoplasty with or without orbicularis resection seems to have similar effects on IVCCM, DED, and MGAL parameters. However, incorporating an orbicularis muscle resection in a blepharoplasty operation could slightly elevate the eyebrow position.

Morphological alterations in corneal nerves of patients with dry eye and associated biomarkers

The purposes of the present study were to (1) identify the relationship between dry eye symptoms and morphological changes in corneal subbasal nerves/ocular surfaces, and (2) discover tear film biomarkers indicating morphological changes in the subbasal nerves. This was a prospective cross-sectional study conducted between October and November 2017. Adults with dry eye disease (DED, n = 43) and healthy eyes (n = 16) were evaluated based on their subjective symptoms and ophthalmological findings. Corneal subbasal nerves were observed using confocal laser scanning microscopy. Nerve lengths, densities, branch numbers, and nerve fiber tortuosity were analyzed using ACCMetrics and CCMetrics image analysis systems; tear proteins were quantified by mass spectroscopy. Compared with the control group, the DED group had significantly lower tear breakup times (TBUT) and pain tolerance capacity, and significantly higher corneal nerve branch density (CNBD) and corneal nerve total branch density (CTBD). CNBD and CTBD showed significant negative correlations with TBUT. Six biomarkers (cystatin-S, immunoglobulin kappa constant, neutrophil gelatinase-associated lipocalin, profilin-1, protein S100-A8, and protein S100-A9) showed significant positive correlations with CNBD and CTBD. The significantly higher CNBD and CTBD in the DED group suggests that DED is associated with morphological alterations in corneal nerves. The correlation of TBUT with CNBD and CTBD further supports this inference. Six candidate biomarkers that correlate with morphological changes were identified. Thus, morphological changes in corneal nerves are a hallmark of DED, and confocal microscopy may help in the diagnosis and treatment of dry eyes.

Corneal subbasal nerve analysis in patients with primary Sjogren's syndrome: a novel objective grading method and clinical correlations

PURPOSE

To investigate corneal sub-basal nerve morphology changes in primary Sjogren's syndrome (SS) dry eye (SSDE) patients and determine the association with disease severity at microstructural level.

METHODS

Twenty-eight eyes of 17 SSDE and 82 eyes of 47 age- and sex-matched non-SS dry eye (NSSDE) patients were included. The Ocular Surface Disease Index questionnaire (OSDI), Schirmer's test (ST), tear meniscus height (TMH), non-invasive breakup time (NIBUT), meibomian gland (MG) morphology, and ocular staining score (OSS) were assessed. In vivo confocal microscopy was performed to observe corneal sub-basal nerve morphology (length, reflectivity, width, and tortuosity). Associations between clinical features and nerve parameters were analysed.

RESULTS

SSDE patients more frequently had increased nerve reflectivity (151.12 ± 17.07 vs. 139.37 ± 14.31 grey value), width (4.45 ± 0.87 vs. 3.92 ± 0.81 μm), tortuosity (132.90 ± 8.04 vs. 129.50 ± 7.33 degree), and higher reflectivity, width, and total nerve grades than NSSDE individuals (all P < 0.05). Significant associations were found between nerve reflectivity/width and anti-SSA [OR = 1.139 (1.013-1.281)/1.802 (1.013-4.465)]/labial gland biopsy [OR = 1.046 (1.002-1.161)/1.616 (1.020-3.243)]. Higher nerve width was associated with increased OSDI [β = 0.284 (0.187-0.455)], MG score [β = 0.185 (0.109-0.300)] and OSS [β = 0.163 (0.020-0.345)], but decreased NIBUT [β =  - 0.247 (- 0.548 ~  - 0.154)]. Higher nerve total grade was associated with increased OSDI [β = 0.418 (0.157-0.793)] and OSS [β = 0.287 (0.027-0.547)], but decreased ST [β =  - 0.410 (-0.857 ~  - 0.138)].

CONCLUSIONS

Corneal nerve morphology changes associated with clinical features in SS patients. These changes may facilitate severity evaluation and management of the disease.

Trigeminal Nerve Affection in Patients with Neuro-Sjögren Detected by Corneal Confocal Microscopy

Background: Patients with Sjögren’s syndrome and polyneuropathy more frequently develop cranial nerve affection when compared to patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We therefore aimed to analyze trigeminal corneal nerve fibre characteristics in both patient groups. Methods: A total of 26 patients with Sjögren’s syndrome associated neuropathy and 29 patients with CIDP were recruited at our university hospital and compared to 6 healthy controls. Dry eye symptoms and signs were assessed via clinical examination and the Ocular Disease Surface Index questionnaire. Trigeminal corneal nerve fibres were analyzed via corneal confocal microscopy (CCM) as a non-invasive in vivo microscopy. Results: CCM revealed significantly reduced corneal nerve fibre density and corneal nerve fibre main branch density in the Neuro-Sjögren group when compared with healthy controls. There were no significant group differences between the Neuro-Sjögren and the CIDP group for any of the microscopic parameters. Dry eye assessment showed similarly reduced scores for both patient groups, while healthy controls showed better results for objective dry eye signs. There was no correlation between microscopic parameters of the corneal confocal microscopy and parameters of dry eye assessment. Conclusions: Our data revealed trigeminal corneal nerve affection in patients with neuropathy associated with Sjögren’s syndrome and patients with CIDP detected by CCM. No difference was found between both neuropathy groups indicating that CCM is not able to distinguish between both entities.

In vivo confocal microscopic study of corneal innervation in Sjögren's Syndrome with or without small fiber neuropathy

PURPOSE

To study changes in the subbasal nerve plexus by In vivo confocal microscopy (IVCM) in Sjögren's Syndrome (SS) with or without associated Small Fiber Neuropathy (SFN), in order to prevent diagnostic delay.

METHODS

Seventy-one patients with SS, including 19 with associated SFN, 20 healthy volunteers and 20 patients with Meibomian gland dysfunction (MGD) were included in this retrospective case-control study. IVCM was used to investigate subbasal nerve plexus density and morphology.

RESULTS

Corneal sensitivity as evaluated with the Cochet-Bonnet aesthesiometer was significantly reduced in the SS group versus the control group (P = 0.026) and the MGD group (P = 0.037). The number of inflammatory cells was significantly increased in the SS group to 86.2 ± 82.1 cells/mm² compared to the control group (P < 0.001). The density of the subbasal nerve plexus was significantly reduced to 16.7 ± 6.5 mm/mm² in the SS group compared to the control group (P < 0.005) and the MGD group (P = 0.042). The tortuosity of the nerves in the SS group was significantly increased compared to the control group (P < 0.001) and the MGD group (P = 0.025). The average number of subbasal nerve plexus neuromas was significantly increased in the SS group compared to the control group (P = 0.001), with a significant increase in the average number of neuromas in SS patients with associated SFN compared to SS patients without SFN (P = 0.008).

CONCLUSION

IVCM can be useful to detect corneal nerve changes in SS patients and may allow earlier diagnosis of the disease and to consider new therapeutic approaches.

In vivo Confocal Microscopic Evaluation of Previously Neglected Oval Cells in Corneal Nerve Vortex: An Inflammatory Indicator of Dry Eye Disease

This study aimed to investigate the association of between previously neglected oval cells located in the corneal vortex and dry eye disease (DED). This was an observational, prospective study involving 168 patients with different degrees of DED. In vivo confocal microscopy was used to observe the corneal subbasal nerves and Langerhans cells (LCs) in the corneal vortex and periphery. Bright and oval cells were also observed in the corneal vortex. An artificial intelligence technique was used to generate subbasal nerve fiber parameters. The patients were divided into the three groups based on the presence of inflammatory cells. Group 2 patients showed a significant increase in the corneal peripheral nerve maximum length and average corneal peripheral nerve density. Patients in group 3 had more LCs than other patients. A bright and oval cell was identified in the corneal vortex, which might be a type of immature LC related to the disease severity of DED.

Corneal sub-basal nerve plexus assessment and its association with phenotypic features and lymphocyte subsets in Sjögren's Syndrome

PURPOSE

To assess and compare corneal sub-basal nerve plexus morphology with circulating lymphocyte subsets, immunologic status and disease activity in Sjögren syndrome (SjS) patients.

METHODS

Fifty-five SjS patients, 63 Sicca patients (not fulfilling SjS criteria), 18 rheumatoid arthritis (RA) patients and 20 healthy controls (HC) were included. Systemic disease activity in SjS was assessed with the ESSDAI score. Lymphocyte subpopulations were studied with flow cytometry. Corneal confocal microscopy and ImageJ software were used to characterize corneal sub-basal nerve plexus in terms of nerve density (CNFD), length (CNFL) and tortuosity (CNFT). Conventional dry eye tests were also performed.

RESULTS

CNFL and CNFD were lower in SjS, Sicca and RA groups, compared to HC (p < 0.001 for both SjS and Sicca); CNFL p = 0.005, CNFD p = 0.018 in RA). CNFT was higher in SjS, followed by Sicca, RA and HC. A negative correlation was found between ESSDAI score and CNFL (r=-0.735, p = 0.012). CNFL correlated negatively with IL21⁺ CD8⁺ T cells (r=-0.279, p = 0.039) and a positively with total memory (r = 0.299, p = 0.027), unswitched memory (r = 0.281, p = 0.038) and CD24^Hi CD27⁺ (r = 0.278, p = 0.040) B cells. CNFD showed a tendency to significance in its negative correlation with ESSDAI (r=-0.592, p = 0.071) and in its positive correlation with switched memory B cells (r = 0.644, p = 0.068).

CONCLUSIONS

This is the first study aiming to correlate ocular findings with lymphocyte subsets in SjS. The associations founded between CNFL and CNFD and disease activity, IL21⁺ follicular T cells and some B-cell subsets suggest that corneal nerve damage may parallel systemic disease activity and inflammatory cells' dynamics.

Corneal nerve structure in patients with primary Sjögren's syndrome in China

Background

The aim of this study was to evaluate the in vivo confocal microscopic morphology of corneal subbasal nerves and its relationship with clinical parameters in patients with primary Sjögren’s syndrome in China.

Methods

This was a case control study of 22 dry eye disease (DED) patients with primary Sjögren’s syndrome (pSS) and 20 control subjects with non-Sjögren dry eye disease (NSDE). Each patient underwent an evaluation of ocular surface disease using the tear film break-up time (TBUT), noninvasive tear film break-up time (NIKBUT), noninvasive tear meniscus height (NIKTMH), corneal staining (National Eye Institute scale, NEI), Schirmer I test, meibography, and corneal subbasal nerve analysis with in vivo confocal microscopy (IVCM). The right eye of each subject was included in this study.

Results

SS patients showed a shorter TBUT (P = 0.009) and Schirmer I test results (P = 0.028) than the NSDE group. However, there was no significant difference in NIKBUT between the two groups (P = 0.393). The nerve density of subbasal nerves, number of nerves and tortuosity of the SS group were significantly lower than those of the NSDE group (P = 0.001, P < 0.001 and P = 0.039, respectively). In the SS group, the mean nerve length was correlated with age and the Schirmer I test (r = − 0.519, P = 0.013 and r = 0.463, P = 0.035, respectively). Corneal staining was correlated with nerve density and the number of nerves (r = − 0.534, P = 0.013 and r = − 0.487, P = 0.025, respectively).

Conclusions

Sjögren syndrome dry eye (SSDE) patients have more severe clinical dry eye parameters than non-Sjögren dry eye disease (NSDE) patients. Compared with NSDE patients, we found that SSDE patients showed decreased corneal subbasal nerve density and numbers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01967-7.

Quantification of Increased Corneal Subbasal Nerve Tortuosity in Dry Eye Disease and Its Correlation With Clinical Parameters

Purpose

This study quantified corneal subbasal nerve tortuosity in dry eye disease (DED) and investigated its correlation with clinical parameters by proposing an aggregated measure of tortuosity (Tagg).

Methods

The sample consisted of 26 eyes of patients with DED and 23 eyes of healthy volunteers, which represented separately the dry eye group and the control group. Clinical evaluation of DED and in vivo confocal microscopy analysis of the central cornea were performed. Tagg incorporated six metrics of tortuosity. Corneal subbasal nerve images of subjects and a validation data set were analyzed using Tagg. Spearman's rank correlation was performed on Tagg and clinical parameters.

Results

Tagg was validated using 1501 corneal nerve images. Tagg was higher in patients with DED than in healthy volunteers (P < 0.001). Tagg was positively correlated with the ocular surface disease index (r = 0.418, P = 0.003) and negatively correlated with tear breakup time (r = -0.398, P = 0.007). There was no correlation between Tagg and visual analog scale scores, corneal fluorescein staining scores, or the Schirmer I test.

Conclusions

Tagg was validated for quantification of corneal subbasal nerve tortuosity and was higher in patients with DED than in healthy volunteers. A higher Tagg may be linked to ocular discomfort, visual function disturbance, and tear film instability.

Translational Relevance

Corneal subbasal nerve tortuosity is a potential biomarker for corneal neurobiology in DED.

In vivo Confocal Microscopic Evaluation of Corneal Dendritic Cell Density and Subbasal Nerve Parameters in Dry Eye Patients: A Systematic Review and Meta-analysis

Purpose: To conduct a systematic review and meta-analysis of the available research on evaluating changes in corneal dendritic cell density (CDCD) and the main subbasal nerve parameters (SNPs) on the ocular surface and assessing the diagnostic performance of in vivo confocal microscopy in patients with dry eye disease. Methods: A computerized systematic review of literature published in PUBMED, EMBASE, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials until May 8, 2020 was performed. All statistical analyses were conducted in RevMan V.5.3 software. The weighted mean differences (WMDs) and standardized mean differences (SMDs) with 95% confidence intervals (CI) between dry eye patients and healthy subjects were presented as results. Results: A total of 11 studies with 755 participants were recruited, and 931 eyes were included in this meta-analysis. However, not all studies reported both CDCD and SNPs. CDCD in the central cornea was higher (WMD = 51.06, 95% CI = 39.42-62.71), while corneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) were lower (WMD = -7.96, 95% CI = -12.12 to -3.81; SMD = -2.30, 95%CI = -3.26 to -1.35) in dry eye patients in comparison with the corresponding values in healthy controls (all p < 0.00001). Conclusion: Taken together, while CNFD and CNFL were lower in dry eye patients, central CDCD showed a significant increase in these patients in comparison with the corresponding values in healthy controls.

A Review of Imaging Biomarkers of the Ocular Surface

A biomarker is a "characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions." Recently, calls for biomarkers for ocular surface diseases have increased, and advancements in imaging technologies have aided in allowing imaging biomarkers to serve as a potential solution for this need. This review focuses on the state of imaging biomarkers for ocular surface diseases, specifically non-invasive tear break-up time (NIBUT), tear meniscus measurement and corneal epithelial thickness with anterior segment optical coherence tomography (OCT), meibomian gland morphology with infrared meibography and in vivo confocal microscopy (IVCM), ocular redness with grading scales, and cellular corneal immune cells and nerve assessment by IVCM. Extensive literature review was performed for analytical and clinical validation that currently exists for potential imaging biomarkers. Our summary suggests that the reported analytical and clinical validation state for potential imaging biomarkers is broad, with some having good to excellent intra- and intergrader agreement to date. Examples of these include NIBUT for dry eye disease, ocular redness grading scales, and detection of corneal immune cells by IVCM for grading and monitoring inflammation. Further examples are nerve assessment by IVCM for monitoring severity of diabetes mellitus and neurotrophic keratitis, and corneal epithelial thickness assessment with anterior segment OCT for the diagnosis of early keratoconus. However, additional analytical validation for these biomarkers is required before clinical application as a biomarker.