Second Comparative Study of Specular Microscopes for Endothelial and Corneal Cell Measurements

Inclusion Criteria - Non-Pathologic Young Adults (18-28 years old) and Non-Pathologic Adults (29-80 years old): * Male or female subjects from 18 to 80 years old who have full legal capacity to volunteer on the date the informed consent is signed; * Subjects who can follow the instructions by the clinical staff at the clinical site, and can attend examinations on the scheduled examination date; * Subjects who agree to participate in the study. Inclusion Criteria - Pathologic Adults (29-80 years old) * Male and female subjects from 29 to 80 years old who have full legal capacity to volunteer on the date the informed consent is signed; * Subjects who can follow the instructions by the clinical staff at the clinical site, and can attend examinations on the scheduled examination date; * Subjects who agree to participate in the study; * At least one eye with any of the following conditions: * History of post-op surgical trauma including Pseudophakic or Aphakic bullous keratopathy; * History of corneal transplant; * Physical injury or trauma to the cornea; * Long term Fuch's dystrophy, Guttata, or other corneal endothelial dystrophies * Keratoconus; * Long term polymethyl methacrylate PMMA contact lens use (greater than 3 years). Exclusion Criteria - Non-Pathologic Young Adults (18-28 years old) and Non Pathologic Adults (29-80 years old) * History of post-op surgical trauma including bullous keratopathy; * History of corneal transplant; * Evidence of physical injury or trauma to the cornea; * Long term Fuch's dystrophy, Guttata or other corneal endothelial dystrophies; * Keratoconus; * Long term PMMA contact lens use (greater than 3 years); * History of cataract, refractive or ocular surgical procedures that render the cornea opaque or otherwise impact its ability to be imaged using the investigational device; * Fixation problems which may prevent obtaining good quality SP-1P and CELLCHEK PLUS in either eye. Exclusion Criteria - Pathologic Adults (29-80 years old): * History of cataract, refractive or ocular surgical procedures that render the cornea opaque or otherwise impact its ability to be imaged using the investigational device; * Fixation problems which may prevent obtaining good quality SP-1P and CELLCHEK PLUS in either eye.