Association of Elevated Thyroid-Stimulating Hormone With Structural Progression in Keratoconus

Area of Science:

• Ophthalmology
• Endocrinology
• Corneal Disease Research

Background:

• Keratoconus is a progressive corneal ectasia.
• The role of systemic factors in keratoconus progression is not fully understood.

Purpose of the Study:

• To investigate the association between serum thyroid hormone levels and structural progression in keratoconus.
• To determine if thyroid-stimulating hormone (TSH), total T3, or free T4 correlate with keratoconus advancement.

Main Methods:

• A prospective observational study included 133 eyes from 74 individuals.
• Participants were categorized into progressive keratoconus, stable keratoconus, and healthy control groups.
• Progression was defined by a ≥1.0 D increase in maximum keratometry (Kmax) over 12 months. Serum hormone assays (TSH, T3, T4) and corneal imaging were performed.

Main Results:

• The progressive keratoconus group showed significantly higher serum TSH levels compared to controls (P < 0.05).
• Serum TSH levels positively correlated with steep keratometry (K2) (r = +0.27, P < 0.05) and negatively with thinnest pachymetry (r = -0.21, P < 0.05).
• No significant differences or correlations were found for total T3 or free T4 levels.

Conclusions:

• Elevated TSH is associated with markers of structural progression in keratoconus.
• These findings suggest a potential systemic thyroid contribution to keratoconus disease evolution.
• Endocrine screening may be beneficial for patients with early or progressive keratoconus.