Inclusion Criteria:  Glaucoma patients having confirmed optic nerve damage with visual field defects consistent with the glaucomatous optic neuropathy or Glaucoma-suspects being followed because of elevated IOP, and/or because of other risk factors for developing glaucoma or optic nerve damage.  Exclusion Criteria:  Active ocular infection (e.g., pink eye or infectious conjunctivitis) Recent trauma to the eye including corneal laceration or corneal/scleral perforation Disabling arthritis or difficulty handling the tonometer Severe difficulty in opening the eyes including abnormal contractions or twitches of the eyelid (blepharospasm) Involuntary, rapid, and repetitive eye movements (nystagmus) Low uncorrected near visual acuity of 20/200 or below Significant glaucomatous central field loss Only one functional eye Poor or off-center visual fixation Poor hearing and/or communicates using sign language Keratoconus (or other corneal disorder) Congenitally small eye (microphthalmos) Enlarged eyeball from the childhood glaucoma (buphthalmos) Previous experience using or interacting with the HOME tonometer during usability tests or clinical trials Any affiliation with Icare and its employees High corneal astigmatism (>3d) History of prior invasive corneal surgery including corneal laser surgery less than six months ago (e.g., LASIK, LASEK, Smile) Corneal scarring Very thick or very thin corneas (central corneal thickness greater than 600 μm or less than 500 μm) Cataract extraction within the last 2 months Wearing contact lenses during the study