Fluid in the retina refers to leakage from the abnormal blood vessels associated with wet macular degeneration. While this is different from bleeding, the abnormal blood vessels can leak either fluid or blood, and some-times leak both.
Both are indicative of wet macular degeneration. While both are damaging, fluid may be less damaging, as fluid often reabsorbs easier and/or faster and the visual deficit from fluid is not as dense as that from blood.
The presence or absence of fluid is the characteristic finding followed by OCT. Resolution of fluid, as monitored by OCT, is related to a patient’s response to therapy and/or spontaneous improvement.
Recurrence of fluid or discovery of new fluid is often an indication for treatment, either initiation of treatment for the first time or retreatment after a period of observation.
Fluorescein angiography provides critical information about leakage and is often helpful in the initial diagnosis of wet macular degeneration, but it does not provide quantitative measurements of the fluid that is present at a given time like OCT does.
Fluorescein angiography is ordered far less frequently than OCT; typically when difficult treatment decisions are being considered, such as whether it is safe to hold treatment or why the treatment response is suboptimal.