Inclusion Criteria:

• Age 18-50 years, female or male
• Fibromyalgia group: diagnosis of fibromyalgia according to 2016 ACR criteria
• Ability and willingness to provide written informed consent
• Adequate ocular media clarity suitable for OCT imaging
• Control group: age- and sex-matched healthy volunteers

Exclusion Criteria:

• Ocular exclusions: cataract or other media opacity; glaucoma or optic nerve disease; ocular surface disorders (e.g., dry eye disease); retinal diseases (e.g., diabetic retinopathy, macular disease); ocular surgery or eye/head trauma within the last 3 months; best-corrected visual acuity < 20/20; refractive error > ±3.00 diopters; intraocular pressure > 21 mmHg; use of topical ophthalmic medications
• Systemic/neurologic exclusions: diabetes mellitus; hypertension; hyperlipidemia; thyroid disorders; inflammatory rheumatic/autoimmune diseases; polyneuropathy or neurodegenerative disease; major depressive disorder or anxiety disorder; heavy smoking (>20 cigarettes/day); alcohol or substance dependence; excessive caffeine intake (>2.5 cups/day)