Recent Android mobile device technology is available which allows user-measured refractive error and reading add power. This technology could be quite useful to the clinical and research community. The current study aims to evaluate the accuracy, repeatability, and reproducibility of one such technology by VisionApp, specifically with regard to refraction and presbyopia.

VisionApp is an app which runs on a smartphone or other device which uses the distance between the user's face and the phone to determine refractive error, while the user looks at different targets (lines, letters, words, etc).

Subjects will be enrolled at the Clinical Optics Research Lab at Indiana University and complete a single study visit.

At the study visit, demographic and health/ocular history may be collected by oral history and standard clinical testing including refraction (check of glasses prescription), auto-refraction or aberrometry may be performed. Visual acuity and room lighting checks may also be measured using standard clinical techniques.

For the experimental portion of the study visit, the subject will look at a phone running the VisionApp program set at a particular distance (calibration) and then be instructed to move further from, or closer to the phone, until a given target (letter, lines, patterns, etc) are more or less clear. Each test may be repeated until at least 10 good data points are collected. This may be done on the right eye, left eye, or both eyes.

Inclusion Criteria:

• at least 40 years of age and currently wears a near add correction
• has a refractive error between Plano and -5.00 D of sphere and cylinder components combined.
• has best corrected visual acuity of at least 20/20 in each eye
• is not amblyopic or have any diagnosed ocular disease
• is willing and able to follow instructions and maintain the appointment schedule

Exclusion Criteria:

• has any systemic disease affecting ocular health and visual acuity
• is currently using any systemic or topical medications that could affect ocular health and visual acuity
• is participating in another eye related research study

Participants were monitored/assessed for adverse events during the study, up to 1 hour