Tear Mediators in Corneal Ectatic Disorders.

Area of Science:

• Ophthalmology
• Biochemistry
• Corneal Diseases

Background:

• Pellucid marginal degeneration (PMD) and keratoconus (KC) are distinct corneal ectatic disorders.
• Biochemical differences between PMD and KC are not well-established.
• Tear mediators may offer insights into the pathogenesis of these conditions.

Purpose of the Study:

• To compare tear mediator concentrations between PMD and KC.
• To identify biochemical differences between these two corneal diseases.

Main Methods:

• A cross-sectional study enrolled patients with corneal ectasia diagnosed via slit-lamp biomicroscopy and Pentacam HR.
• Tear samples were collected from 9 eyes of 7 PMD patients, 55 eyes of 55 KC patients, and 24 healthy controls.
• Concentrations of 11 tear mediators, including matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases (TIMP)-1, were measured using Cytometric Bead Array.

Main Results:

• Matrix metalloproteinase-9 (MMP-9) was the sole mediator showing significant variance between PMD and KC groups (p = 0.005).
• The ratios of MMP-9 to TIMP-1 were 2.45 in PMD, 0.40 in KC, and 0.23 in controls.

Conclusions:

• This is the first study to investigate biochemical differences between PMD and KC using tear mediators.
• Matrix metalloproteinase-9 (MMP-9) may serve as a potential biomarker differentiating PMD from KC.
• Further research with larger cohorts is needed to validate these findings and explore the molecular alterations in PMD.