Intra-surgical Evaluation of CATS Tonometer Prism and Abbott Medical Optics Versus Alcon Phacoemulsification Machines

Inclusion Criteria: * • Age 18 or greater * Bilateral cataracts for which phacoemulsification extraction and posterior IOL implantation has been planned for both eyes * Subjects able to give informed consent * Nuclear Sclerotic cataract graded 2+ or 3+ * Naturally dilated pupil size (in dim light) \> 4.0 mm (with no dilation medications) for both eyes * Preoperative corneal astigmatism of 2.5 D or less * Ages between 55 and 80 * Availability, willingness, and sufficient cognitive awareness to comply with examination procedures Exclusion Criteria: * • Uncontrolled systemic disease that in the opinion of the Investigator would put the subject's heath at risk * Intraoperative complications * Subjects with only one functional eye * Those with one eye having poor or eccentric fixation * Mild or severe cataracts, predominantly posterior subcapsular cataracts * High corneal astigmatism (i.e. those eyes displaying an oval contact image) * Those with corneal scarring or who have had corneal surgery including corneal laser surgery * Microphthalmos * Buphthalmos * Severe Dry eyes * Blepharospasm * Nystagmus * Keratoconus * Any other corneal or conjunctival pathology or infection. * Central corneal thickness greater than 0,600 mm or less than 0,500 mm (2 standard deviations about the human mean) * Acute or chronic disease or illness that would increase risk or confound study results (e.g. diabetes mellitus, immunocompromised, etc.) * Uncontrolled systemic or ocular disease * History of ocular trauma or prior ocular surgery * Fuchs Dystrophy * Subjects who may be expected to require retinal laser treatment or other surgical intervention, including LRI's * Capsule or zonular abnormalities that may affect postoperative centration or tilt of the lens (e.g. pseudoexfoliation syndrome) * Pupil abnormalities (non-reactive, tonic pupils, abnormally shaped pupils, or pupils that do not dilate at least 4.0 mm under mesopic/scotopic conditions) * Contact lens usage within 6 months for PMMA contacts lenses, 1 month for gas permeable lenses or 1 week for extended-wear and daily-wear soft contact lens