Screening Aid to Identify Corneas That May Have Pathologies or Other Conditions

• To establish reference values for SF, CIM, and TKM in subjects with normal corneas.
• To establish reference values for SF, CIM, and TKM in subjects who underwent myopic laser vision correction.
• To establish reference values for SF, CIM, and TKM in subjects who underwent hyperopic laser vision correction.
• To establish reference values for SF, CIM, and TKM in subjects who were diagnosed to have keratoconus.
• To establish reference values for SF, CIM, and TKM in subjects with history of orthokeratology.
• To establish reference values for SF, CIM, and TKM in subjects with previously diagnosed corneal conditions (diseases/pathologies/surgeries) affecting the corneal surface that are not listed above.
• To determine the repeatabiltity and reproducibility of the Atlas II corneal topographer in normal human corneas using true elevation data and axial curvature.
• To determine the sensitivity, specificity, and accuracy of the Pathfinder II Corneal Analysis software in discriminating normal corneas from previously diagnosed corneal conditions (diseases/pathologies/surgeries) affecting the corneal surface (Phase II).

Inclusion criteria

Normals

• Patients seeking initial laser vision correction that were screened to be good candidates for the procedure.
• No history of refractive or other ocular surgery.
• No corneal pathologies.
• Normal corneal topography.
• Contact lens wearers should discontinue use at least 2 weeks for hard contacts, and 3 days for soft lenses prior to imaging.

Keratoconus

• An irregular cornea determined by distorted keratometry mires, distortion of the retinoscopic, or ophthalmoscopic red reflex (or a combination of these)
• At least one of the following biomicroscopic signs: Vogt's striae, Fleischer's ring of >2 mm arc, or corneal scarring consistent with keratoconus.
• Contact lens wearers should discontinue use preferably 1 day or at least half an hour prior to imaging.

Myopic Laser Vision Correction

Patients who have undergone myopic:

• LASIK
• PRK
• LASEK

Hyperopic Laser Vision Correction

Patients who have undergone hyperopic:

• LASIK
• PRK
• LASEK

Orthokeratology

• Patients using specially designed rigid contact lenses to reshape the cornea to temporarily reduce or eliminate refractive error.
• Subjects must be 18 years of age or older; able and willing to make the required visit; and able and willing to give consent.

Exclusion criteria

• Patients that underwent corneal transplantation or any ocular surgery for the following categories: normal, keratoconus, and orthokeratology)
• Any active infection or inflammation of the cornea.
• PI decides that subject is not suitable due to medical risk.