The research assistant is primarily responsible for assisting in research patient visits according to International Council for Harmonisation Good Clinical Practice (ICH-GCP) guidelines and according to the Institutional Review Board (IRB)-approved study protocol and/or manual of procedures. Perform trial frame refraction and Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity testing (For Investigator Sponsored Trials (IST)s only, at selected sites).