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 (and other corneal endothelial dystrophies) * Keratoconus; * Long term 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 corneal transplant; * Long term Fuch's dystrophy (and other corneal endothelial dystrophies); * Keratoconus; * Guttata; * Diabetes mellitus type I or type II; * 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; * All contact lens wearers; * Fixation problems which may prevent obtaining good quality SP-1P and CELLCHEK PLUS in either eye. Exclusion Criteria -Pathologic Adults (29-80 years old): * Fixation problems which may prevent obtaining at least poor quality (refer to Figure 1) SP-1P and KONAN CELLCHEK PLUS images in either eye.