The association between keratoconus and allergic eye diseases: A systematic review and meta-analysis

Causal Links Between Systemic Disorders and Keratoconus in European Population

PURPOSE

To establish the presence of a causal linkage between prevalent systemic diseases and keratoconus (KC).

DESIGN

Mendelian randomization (MR) analysis.

METHODS

After an exhaustive screening process, genetic variants linked to various systemic diseases were identified as instrumental variables at the genome-wide significance level. Subsequently, MR analyses were conducted to elucidate their potential causal connection with KC (N = 26,742). The encompassed systemic ailments comprise diabetes, hay fever/allergic rhinitis/eczema, obstructive sleep apnea, thyroid dysfunction, aortic aneurysm, major depressive disorder, inflammatory bowel disease (including Crohn's disease and ulcerative colitis), and mitral valve prolapse. Our study adheres to the principles of Strengthening the Reporting of Observational Studies in Epidemiology Using MR guidelines.

RESULTS

Using inverse variance weighting as the primary MR analysis method, our findings revealed that hay fever/allergic rhinitis/eczema (odds ratio, 10.144; 95% CI, 2.441-42.149; P = .001) and ulcerative colitis (odds ratio, 1.147; 95% CI, 1.054-1.248; P = .002) were associated with an increased risk of KC within the largest population under scrutiny. Conversely, the prolonged hyperglycemic state did not exhibit a potentially protective effect in delaying the pathogenesis of KC, and no correlation was observed between the two (odds ratio, 0.320; 95% CI, 0.029-3.549; P = .353). Also, obstructive sleep apnea, thyroid function, aortic aneurysm, major depressive disorder, Crohn's disease, and mitral valve prolapse did not exhibit a causal association with KC (P > .05 for all comparisons).

CONCLUSIONS

This study indicates an increased risk of KC related to hay fever/allergic rhinitis/eczema and ulcerative colitis, with diabetes not providing a protective effect. These findings may potentially contribute some insights to inform clinical interventions.

Squishy matters - Corneal mechanobiology in health and disease

The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.

[Current aspects of vernal and atopic keratoconjunctivitis]

BACKGROUND

Vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) are complex and rare diseases. Thus, their diagnosis and treatment are often a challenge.

OBJECTIVE

Discussion on the epidemiology, new pathogenetic concepts, interesting clinical findings, diagnostic possibilities and new treatment options and their side effects in severe ocular allergies. Analysis of the presentation of VKC in the internet.

MATERIAL AND METHODS

Evaluation of recent review articles, original publications, and case reports on the topics of VKC and AKC over the past 5 years.

RESULTS

Ocular allergies have significantly increased over the last decades. Recent concepts discussed in the pathogenesis of VKC and AKC are the role of the local and gut microbiome as well as the influence of neuroinflammation. Keratoconus is significantly more common in patients with VKC and AKC compared to the normal population. It is associated with faster progression and a more severe course of disease. A conjunctival provocation test is only rarely necessary in the diagnosis of allergic conjunctivitis. Treatment of atopic dermatitis with dupilumab, an interleukin 4 receptor alpha (IL-4Ra) antagonist, can cause ocular side effects. Unfortunately, information available on the internet for patients and parents on the topic of VKC is sometimes dangerously incorrect.

CONCLUSION

From the abovementioned new pathogenetic concepts, preventive and personalized treatment options could be developed in the future. Keratoconus in AKC/VKC must be recognized and treated early. Official guidelines are now available for a standardized conjunctival provocation test in the diagnosis of allergic conjunctivitis. The unwanted ocular side effects of dupilumab are often difficult to discriminate from the actual underlying AKC and respond well to anti-inflammatory treatment. Patients with VKC must be informed about the incorrect information on the internet regarding their disease.

Keratoconus Diagnosis: From Fundamentals to Artificial Intelligence: A Systematic Narrative Review

The remarkable recent advances in managing keratoconus, the most common corneal ectasia, encouraged researchers to conduct further studies on the disease. Despite the abundance of information about keratoconus, debates persist regarding the detection of mild cases. Early detection plays a crucial role in facilitating less invasive treatments. This review encompasses corneal data ranging from the basic sciences to the application of artificial intelligence in keratoconus patients. Diagnostic systems utilize automated decision trees, support vector machines, and various types of neural networks, incorporating input from various corneal imaging equipment. Although the integration of artificial intelligence techniques into corneal imaging devices may take time, their popularity in clinical practice is increasing. Most of the studies reviewed herein demonstrate a high discriminatory power between normal and keratoconus cases, with a relatively lower discriminatory power for subclinical keratoconus.