This study aims to determine whether corneal nerve function and morphology are affected by tear film instability and ocular surface homeostasis loss. Additionally, it seeks to investigate whether these factors vary based on the severity of dry eye symptoms.

Inclusion Criteria:

• Group with DED: Diagnosis of DED based on the TFOS DEWS II report
• Group without DED: No diagnosis of DED

Exclusion Criteria:

• Exclusion criteria:
• Systemic disease that may affect ocular health and innervation
• injury or history of operations on the anterior or posterior segment of the eye, which can affect the corneal structure and physiology
• regular application of systemic or ocular medication known to affect the tear film except from DED medications
• eye drops or makeup on the day of measurement.

Remarks:

Contact lens wearers are asked not to wear contact lenses for 1 week before the first appointment.

Participant with DED medications will be asked to use only conservative-free eye drops on the days of examination

healthy adults as well as adult with dry eye disease