Relating Retinal Structural and Functional Parameters to Visual Acuity in Eyes Undergoing Treatment for Diabetic Macular Edema

Inclusion Criteria:

• Males and females age ≥ 18 years
• DME involving the central fovea (≥325 micrometers central subfield thickness on Spectralis SD-OCT)
• Scheduled to undergo treatment of DME with intravitreal bevacizumab or ranibizumab
• Willing to sign informed consent, comply with study protocol requirements, and undergo at least 2.5 hours of testing per visit;

Exclusion Criteria:

• Lens opacity ≥ grade 3 ARLNS on standard photographs
• Incisional ophthalmic surgery of any kind within 4 months of study enrollment
• Treatment for DME within the past 4 months
• Active proliferative diabetic retinopathy
• History of vitrectomy
• Glaucoma
• Uncontrolled hypertension (≥ 180 systolic or ≥ 110 diastolic on two successive measures)
• Females of childbearing potential who are unwilling or unable to use an acceptable method of contraception throughout the study
• Females who are pregnant, lactating or breastfeeding at time of enrollment
• Subjects with a history of a serious hypersensitivity reaction to treatment or components of the study assessment
• History of any radiation in or around the eyes
• History of visually significant non-diabetic retinopathy or choroidopathy (e.g. age-related macular degeneration, polypoidal choroidal vasculopathy, central serous retinopathy, retinal vein occlusion, sickle cell retinopathy)
• History of optic neuropathy
• Neurological conditions that can impair vision (e.g. Parkinson's disease, multiple sclerosis, Alzheimer's disease)
• Liver disease (e.g. cirrhosis, hepatitis)
• History of small bowel surgery
• Anticipated need for intravitreal triamcinolone injections
• Dilated pupil diameter less than 6 millimeters
• High myopia (refractive error spherical equivalent ≥ -6 diopters)
• Currently being treated for cancer or any disease likely to adversely affect participation in a 2 year trial
• Participation in any interventional clinical study requiring IRB approval within 3 months of enrollment
• Any findings deemed unacceptable by the Principal Investigator