Corneal Epithelial Thickness Mapping by Anterior Segment Optical Coherence Tomography in Patients With Refractive Errors

Refractive errors are among the most common ocular conditions affecting visual acuity. Corneal epithelial thickness has been suggested to play a role in the optical properties of the eye and may vary among different refractive states. This observational study aims to evaluate corneal epithelial thickness mapping using anterior segment optical coherence tomography (AS-OCT) in patients with refractive errors. Patients will be assessed and categorized according to their refractive status, and epithelial thickness measurements will be obtained and analyzed. The study seeks to investigate potential correlations between epithelial thickness distribution and different types of refractive errors to enhance understanding of corneal biomechanics in refractive conditions.

Primary outcomes

• Measurement of corneal epithelial thickness using AS-OCT [At baseline during a single study visit when participants undergo AS-OCT examination.]: Corneal epithelial thickness will be measured using anterior segment optical coherence tomography (AS-OCT). Measurements will include central and regional epithelial thickness values in microns in patients with different refractive errors.

Secondary outcomes

• Comparison of epithelial thickness between myopic and hyperopic eyes [At baseline (single visit)]: Corneal epithelial thickness will be compared between myopic and hyperopic eyes using AS-OCT measurements.
• Comparison of epithelial thickness in eyes with and without astigmatism [At baseline (single visit)]: Corneal epithelial thickness will be evaluated and compared between eyes with astigmatism and those without astigmatism using AS-OCT.
• Corneal epithelial thickness asymmetry across corneal regions and inter-eye comparison [At baseline (single visit)]: Epithelial thickness will be assessed across different corneal regions and compared between both eyes to evaluate inter-eye asymmetry.
• Comparison of epithelial thickness in low and high refractive errors [At baseline (single visit)]: Corneal epithelial thickness profiles will be compared between low and high degrees of myopia and hyperopia using AS-OCT measurements.

Sex: All, ages: 18 Years to 99 Years, accepts healthy volunteers

Inclusion Criteria:

* Age ≥ 18 years-
* Patients diagnosed with myopia or hyperopia by refraction
* Clear cornea with no evidence of corneal pathology
* Ability to undergo reliable anterior segment imaging

Exclusion Criteria:

* Inability to fixate or follow instructions
* Family history of keratoconus
* Glaucoma,Cataract
* Previous ocular surgery including refractive surgery
* Keratoconus or suspected corneal ectasia
* Corneal opacities or scars
* Contact lens wear within the last two weeks
* Ocular trauma
* systemic disease affecting the cornea ( Such as diabetes)

• Engy Mohamed Mostafa, Professor, Principal investigator, Department of Ophthalmology, Faculty of Medicine, Sohag University
• Amin Abu-Ali Hassan, Assistant Professor, Study director, Department of Ophthalmology, Faculty of Medicine, Sohag University
• Yasmeen Gamal Abd-El latif, Lecturer, Study director, Department of Ophthalmology, Faculty of Medicine, Sohag University