Persons who do not have glaucoma will have pictures taken of the optic nerve with a standard camera before and 2 weeks after starting to take a daily glaucoma eye drop to lower eye pressure. These data will be used to compare to the same procedure performed with glaucoma patients to study how glaucoma injures the eye.

The present proposal seeks to measure biomechanical strains in age-matched control subjects who do not have Open-angle Glaucoma (OAG), using the same non-invasive imaging methods as in the above programs. This is necessary as even undamaged OAG eyes may have different biomechanical properties at baseline than do non-OAG eyes. While there are some limited methods to test strains in control eyes, to compare normal to OAG responses robustly, the same methods of changing intra-ocular pressure (IOP) must be applied-namely to lower IOP by delivery of FDA-approved agent, latanoprost, as has been done in the investigator's OAG subjects. The method of measuring strain requires images taken at two different IOP levels.

Inclusion Criteria:

• Adults who have no history of OAG
• Have an ocular examination by a glaucoma specialist with no indications of OAG
• Have normal optical coherence tomography findings in the retinal nerve fiber layer.
• Over age 30 will be included from
• Both sexes
• All ethnic groups.
• Optic neuropathy.
• Both suspects and those with glaucoma damage will be included.
• When both eyes meet inclusion and exclusion criteria, both eyes will be included in the study and statistical methods will be used to account for correlations between eyes within the same individual.

Exclusion Criteria:

• in whom sitting in an upright position is impossible due to physical disability
• with ocular media opacity, corneal scarring, cataract or vitreous hemorrhage, that does not allow adequate imaging resolution.
• in whom keeping the eyes open during the imaging procedure is not possible or uncomfortable.
• who cannot perform home tonometry accurately at certification
• who do not have reliable clinical Optical Coherence Tomography (OCT) testing.
• with any form of glaucoma
• with high myopia defined as refractive error > -8
• with past keratorefractive surgery, corneal dystrophy, or corneal ectasia that would make self-tonometry measurements difficult to interpret
• inability to understand English or with a language or hearing impairment

Biostatistician