Risk of recurrent corneal erosion in patients with diabetes mellitus in Taiwan: a population-based cohort study

The incidence and prevalence of recurrent corneal erosion syndrome in London, UK

BACKGROUND

Recurrent corneal erosion syndrome (RCES) is caused by repeated episodes of corneal epithelial breakdown due to improper adherence of the corneal epithelium to the underlying basement membrane. The most common aetiologies are corneal dystrophy or previous superficial ocular trauma. The incidence and prevalence of the condition is currently unknown. This study aimed to determine the incidence and prevalence of RCES within the London population over a 5-year period in order to better inform clinicians and evaluate how this condition affects ophthalmic service provision.

METHODS

A retrospective cohort study over a 5-year period reviewed 487,690 emergency room patient attendances at Moorfields Eye Hospital (MEH) London between 1 January 2015 and 31 December 2019. MEH caters for a local population comprising of around ten regional clinical commissioning groups (CCGs). The data for this study were collected using OpenEyesTM electronic medical records including demographics and comorbidities. The CCGs encompass 41% (3,689,000) of London's total 8,980,000 inhabitants. Using these data the crude incidence and prevalence rates of disease were estimated with results reported per 100,000 population.

RESULTS

Out of 330,684 patients, 3623 patients were given a new diagnosis of RCES by the emergency ophthalmology services, and from these, 1056 patients attended outpatient follow-up. The crude annual incidence of RCES was estimated at 25.4 per 100,000, with a crude prevalence rate of 0.96%. There was no statistical difference in annual incidence across the 5-year period.

CONCLUSIONS

The period prevalence of 0.96% shows that RCES is not uncommon. There was also a stable annual incidence over the 5-year period, showing no changing trend over the study period. However, identifying the true incidence and period prevalence is a challenging task, as minor cases may heal prior to examination by an ophthalmologist. It is highly likely that RCES is underdiagnosed and therefore underreported.

Matrix Metalloproteinases and the Pathogenesis of Recurrent Corneal Erosions and Epithelial Basement Membrane Dystrophy

Matrix metalloproteinases (MMPs) are a group of proteolytic enzymes which are members of the zinc endopeptidase family. They have the ability to degrade extracellular matrix elements, allowing for the release of binding molecules and cell migration. Although metalloproteinases regulate numerous physiological processes within the cornea, overexpression of metalloproteinase genes and an imbalance between the levels of metalloproteinases and their inhibitors can contribute to the inhibition of repair processes, the development of inflammation and excessive cellular proliferation. The involvement of MMPs in the pathogenesis of dystrophic corneal diseases needs clarification. Our analyses focus on the involvement of individual metalloproteinases in the pathogenesis of recurrent corneal erosions and highlight their impact on the development of corneal epithelial basement membrane dystrophy (EBMD). We hypothesize that abnormalities observed in patients with EBMD may result from the accumulation and activation of metalloproteinases in the basal layers of the corneal epithelium, leading to basement membrane degradation. A barrier formed from degradation materials inhibits the normal migration of epithelial cells to the superficial layers, which contributes to the development of the aforementioned lesions. This hypothesis seems to be lent support by the elevated concentrations of metalloproteinases in the corneal epithelium of these patients found in our previous studies on the relationships between MMPs and recurrent corneal erosions.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

A Population-Based Study of Social Demographic Factors, Associated Diseases and Recurrent Corneal Erosion in Taiwan

Purpose

To investigate the association of recurrent corneal erosion (RCE) with sociodemographic factors and associated ocular conditions or systemic diseases.

Methods

This nationwide, population-based, retrospective, matched case-controlled study included 98,895 RCE patients, identified by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 371.42, were selected from the Taiwan National Health Insurance Research Database. The age-, sex-, and index date- matched control group included 98,895 non-RCE control group also selected from the Taiwan Longitudinal Health Insurance Database 2000. Sociodemographic factors and associated ocular conditions or systemic diseases were examined using univariate logistic regression analyses, and continuous variables were analyzed using paired t-test. The odds ratio (OR) of developing RCE were compared using adjusted logistic regression analysis.

Results

Patients with ocular conditions including corneal abrasion, ocular allergic conditions, and corneal dystrophy were more likely to have RCE than the control group (adjusted OR = 63.56, 95% CI = 42.06-96.06, p < 0.0001; adjusted OR = 24.27, 95% CI = 20.51-28.72, p < 0.0001; adjusted OR = 17.10, 95% CI = 5.14-59.93, p < 0.0001, respectively). Patients with systemic diseases such as diabetes mellitus, hyperlipidaemia, and atopy trait have significantly higher ORs for RCE development. Patients residing in either Northern Taiwan or a metropolis city had higher odds of developing RCE; however, there were no significant differences in income or occupation on the probability to develop RCE.

Conclusion

RCE is strongly associated with corneal abrasion, ocular allergic conditions, corneal dystrophy, diabetes mellitus, hyperlipidaemia, and atopy trait.

Hyperglycemia Induces Meibomian Gland Dysfunction

Purpose

Patients diagnosed with diabetes are inclined to have abnormalities on stability of tear film and disorder of meibomian gland (MG). This study aims to explore the pathological change of MG induced by diabetes in a rat model.

Methods

Sprague-Dawley (SD) rats were intraperitoneally injected with streptozotocin (STZ) to establish a diabetic animal model. Lipid accumulation in MG was detected by Oil Red O staining and LipidTox staining. Cell proliferation status was determined by Ki67 and P63 immunostaining, whereas cell apoptosis was confirmed by TUNEL assay. Gene expression of inflammatory cytokines and adhesion molecules IL-1α, IL-1β, ELAM1, ICAM1, and VCAM1 were detected by RT-PCR. Activation of ERK, NF-κB, and AMPK signaling pathways was determined by Western Blot analysis. Oxidative stress-related factors NOX4, 4HNE, Nrf2, HO-1, and SOD2 were detected by immunostaining or Western Blot analysis. Tom20 and Tim23 immunostaining and transmission electron microscopy were performed to evaluate the mitochondria functional and structure change.

Results

Four months after STZ injection, there was acini dropout in MG of diabetic rats. Evident infiltration of inflammatory cells, increased expression of inflammatory factors, and adhesion molecules, as well as activated ERK and NF-κB signaling pathways were identified. Oxidative stress of MG was evident in 4-month diabetic rats. Phospho-AMPK was downregulated in MG of 2-month diabetic rats and more prominent in 4-month rats. After metformin treatment, phospho-AMPK was upregulated and the morphology of MG was well maintained. Moreover, inflammation and oxidative stress of MG were alleviated after metformin intervention.

Conclusions

Long-term diabetes may lead to Meibomian gland dysfunction (MGD). AMPK may be a therapeutic target of MGD induced by diabetes.

Sociodemographic Factors and Comorbidities Including Hyperparathyroidism Are Associated With an Increased Risk of Band Keratopathy: A Population-Based Study in Taiwan

PURPOSE

To investigate the association of comorbidities including hyperparathyroidism and sociodemographic factors with band keratopathy.

METHODS

This retrospective, population-based, matched case-control study recruited 2,545 patients suffering from band keratopathy. They were selected from the Taiwan National Health Insurance Research Database, based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 371.43. The control group included 15,270 sex-, age-, and index date-matched non-band keratopathy patients collected from the Taiwan Longitudinal Health Insurance Database 2000. To compare band keratopathy patients with controls, McNemar's test was used for nominal data and paired t- tests were used for continuous variables. Univariate conditional logistic regression analysis and multivariable conditional logistic regression were used to obtain the odds ratio (OR) and adjusted OR of developing band keratopathy.

RESULTS

Patients with hyperparathyroidism were more likely to develop band keratopathy than controls (OR, 43.5; 95% confidence interval [CI], 23.789-79.544; P < 0.001) even after conditional logistic regression (adjusted OR, 11.28; 95% CI, 5.461-23.33; P < 0.001). Other conditions that increased the odds of scleritis development included systemic diseases such as chronic kidney disease (CKD) and diabetes mellitus (DM) and ocular conditions such as iridocyclitis, phthisis bulbi, and ever silicone oil retention. Regarding sociodemographic factors, >40% of patients with band keratopathy were aged ≥65 years old. Moreover, patients living in Eastern Taiwan and fishermen had higher odds of developing band keratopathy.

CONCLUSIONS

Band keratopathy is significantly associated with hyperparathyroidism, CKD, DM, iridocyclitis, phthisis bulbi, and ever silicone oil retention.

Association Between Atopic Keratoconjunctivitis and the Risk of Recurrent Corneal Erosion

Purpose: To investigate the risk of recurrent corneal erosion (RCE) in patients with atopic keratoconjunctivitis (AKC).

Methods: This national, retrospective, matched cohort study enrolled 184,166 newly-diagnosed AKC patients, selected from the Taiwan National Health Insurance Research Database and identified by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 372.05. The control group comprised 184,166 non-AKC patients matched by age, sex, and potential comorbidities and they were selected from the Taiwan Longitudinal Health Insurance Database, 2000. Information from patients was gathered from 1 January 2004 to 31 December 2011, and both groups were traced from the index date until December 2013. The incidence and risk of RCE (ICD-9-CM code 361.42) was compared between the groups. The adjusted hazard ratio (HR) for RCE was obtained by a Cox proportional hazard regression analysis. The Kaplan–Meier analysis was performed to calculate the cumulative incidence of RCE.

Results: In total, 564 AKC patients and 406 non-AKC controls developed RCE during the follow-up span. The incidence of RCE was 1.45 times higher in AKC patients than in controls (95% confidence interval [CI] = 1.27–1.64; P < 0.0001). After adjusting for potential confounders, including diabetes mellitus, keratoconjunctivitis sicca, corneal transplantation, ocular blunt trauma, corneal dystrophy, and band keratopathy, AKC patients were 1.36 times more likely to develop RCE than controls (adjusted HR, 1.36; 95% CI = 1.19–1.54; p < 0.05).

Conclusions: AKC Patients had an increased risk of developing RCE and should be informed of this risk.