This retrospective cohort study aims to evaluate the potential effects of anterior clinoid process (ACP) pneumatization on optic canal morphometry and retinal nerve fiber layer (RNFL) thickness. ACP pneumatization is an anatomical variation that may alter the morphology of the optic canal and potentially influence the optic nerve.

Patients aged 18-65 years with available head and neck computed tomography (CT) imaging and optical coherence tomography (OCT) examinations between August 2018 and July 2025 will be retrospectively reviewed. Optic canal length and diameter will be measured using CT images, and RNFL thickness parameters will be obtained from OCT records. Measurements will be compared between patients with and without ACP pneumatization.

Inclusion Criteria:

• Adults aged 18 to 65 years.
• Availability of head and neck computed tomography (CT) imaging in the hospital archive.
• Availability of optical coherence tomography (OCT) examination records in the hospital archive.
• CT and OCT examinations performed between August 2018 and July 2025.

Exclusion Criteria:

• Age <18 years or >65 years. History or evidence of diabetes mellitus. History or evidence of hypertension. Glaucoma. Any condition or diagnosis that may cause optic nerve pathology (e.g., optic neuritis, compressive optic neuropathy, optic atrophy, demyelinating disease affecting the optic nerve).

Inadequate image quality or incomplete CT/OCT data preventing reliable measurements.

This study population consists of adult patients aged 18 to 65 years who underwent both head and neck computed tomography (CT) imaging and optical coherence tomography (OCT) examinations at Elazığ Fethi Sekin City Hospital between August 2018 and July 2025. Patients will be retrospectively identified through the hospital electronic medical record and PACS archive systems. Participants will be categorized based on the presence or absence of anterior clinoid process (ACP) pneumatization on CT imaging.