Evaluation of a Surgical Microscope Mounted Autorefractor When Used on Patients Lying in a Supine Position

The purpose of this study is to evaluate the accuracy and repeatability of an individually validated prototype autorefractor designed to be mounted on a surgical microscope. The goal is to evaluate 20 subjects with both the investigational instrument followed by a commercially available instrument.

Inclusion criteria

• Be at least 18 years of age as of the date of evaluation for the study.
• Have:

• Read the Informed Consent
• been given an explanation of the Informed Consent
• indicated understanding of the Informed Consent
• signed the Informed Consent document.
• Be willing and able to adhere to the instructions set forth in this protocol and able to participate in all scheduled evaluations.
• Be in good general health, based on his/her knowledge.
• Have a refractive error within the range of -10.00 to +30.00 Diopter sphere and up to 5.00 Diopter of refractive cylinder .
• Have manifest refraction (BCVA) Snellen visual acuities (VA) equal to or better than 20/25 in each eye. -

Exclusion criteria

Subjects may not be enrolled in this study if any of the following apply: The subject is/has:

• Allergy to Tropicamide or a previous adverse reaction to Tropicamide.
• Poor personal hygiene as observed by the investigational site personnel.
• Strabismus
• Currently pregnant (to the best of the subject's knowledge) or is lactating.
• Previous refractive surgery or current or previous orthokeratology treatment.
• Aphakic or pseudophakic or has cataracts that interfere with visual acuity.
• Ocular or systemic disease such as, but not limited to: anterior uveitis or iritis (past or present), glaucoma, Sjögren's syndrome, lupus erythematosus, sclerodermia, keratoconus or type II diabetes.
• The need for topical ocular medications or any medication which might interfere with the study evaluations.
• The presence of clinically significant (grade 3 or 4) anterior segment abnormalities; inflammations such as iritis; or any infection of the eye, lids, or associated structures.
• Slit lamp findings, including but not limited to:

Pathological dry eye or associated dry eye symptoms with decreased tear levels and punctuate staining > Grade 2 Pterygium Corneal scars within the visual axis Neovascularization or ghost vessels > 1.0 mm in from the limbus Giant papillary conjunctivitis (GPC) of > Grade 2 Anterior uveitis or iritis Seborrheic eczema, seborrheic conjunctivitis or blepharitis

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