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