Inclusion Criteria:  18 years or above; have been diagnosed with HF of any etiology or healthy control; able to provide informed consent and comply with study protocol; able to undergo retinal evaluation using a handheld, automated, non-mydriatric retinal camera; and able to provide written informed consent.  Exclusion Criteria:  pregnancy or planned pregnancy; photosensitive epilepsy; significant ophthalmologic conditions such as cataract, glaucoma, blindness, or progressive diabetic retinopathy; having undergone retinal laser photocoagulation; any condition which, in the judgment of the investigator, would place a patient at undue risk by being enrolled in the trial, or cause inability to comply with the study.