The purpose of this prospective interventional study is to compare patient experience, ocular surface irritation, and bacterial colony counts and microbial spectrum between povidine iodine and aqueous chlorhexidine as ocular surface antiseptic prior to intravitreal injection

This is a single center prospective study comparing antiseptic efficacy and ocular surface irritation with PI (povidine iodine) and AC (aqueous chlorhexidine). Patients will be recruited in the clinical offices of the Retina Service of Wills and Hospital/Mid Atlantic Retina clinic offices. Patients who are determined to require bilateral intravitreal injections of an anti-VEGF (vascular endothelial growth factor) agents by a retina specialist at their regularly scheduled retina appointment will be evaluated for qualification by study personnel. Patients who meet inclusion criteria will be identified and informed consent will be obtained. Prior to injection, topical anesthetic (0.5% proparacaine, Alcon) will be instilled in both eyes. Study personnel will obtain four samples from the superior and inferior fornices of the upper and lower lids of both eyes using swabs (COPAN ESwab, ThermoFisher Scientific) for patients enrolled at Wills. Topical antisepsis will then be applied, the first eye will be randomized to one drop of either PI 5% or AC 0.1% and the second eye will receive the other agent. One minute after instillation of the eye drop to each eye, patients will rate their pain in each eye using the Wong-Baker (smiley face) rating scale. The injections will then be performed by the treating retina specialist. Following the injection, a second conjunctival culture will be taken in an identical manner to the first for patients enrolled at Wills. Study personnel will then instill fluorescein dye (fluorescein sodium ophthalmic, BioGlo) into each eye, and a brief slit lamp examination will be performed. Study personnel will record surface findings according to the Ocular Surface Score and a numerical score for each eye will be determined. On post-injection day one study personnel will call the patient and ask to rate the pain in each eye using the same verbal numerical rating scale. No additional clinic visits will be required as part of the study.

Inclusion Criteria:

• Current patient of the Wills Eye Hospital Retina Service including all Mid Atlantic Retina offices
• Clinical indication of bilateral intravitreal injection as determined by the treating retina specialist for a diagnosis of age-related macular degeneration, diabetic macular edema, proliferative retinopathy or macular edema associated with retina vein occlusion.
• Age greater than 18.

Exclusion Criteria:

• Documented allergy to PI or AC
• Current diagnosis of infectious keratitis
• History of unilateral contact lens wear in the past 30 days
• Current unilateral use of prescription eye drops.

The participant will be masked to which drug they receive, the investigator performing the analysis will also be masked