The eye doctor performs the following test to diagnose the condition:

Dilated fundus examination

Optical coherence tomography (OCT)

Fundus fluorescence angiography (FFA)
Dilated fundus examination: The eye doctor examines the retina after instilling dilating eye drops. These drops are put at intervals of every 15mins for 3 to 4 times to dilate the pupil, i.e. the colored diaphragm of the eye. The retina is then examined with a high powered convex lens on the slit lamp, to visualize the macula in detail.
OCT: It is an instrument which gives high quality, high resolution three dimensional view of the macula in cross section helping the eye doctor to know the exact pathology which can help appropriate treatment.
FFA: It is a test done to visualize and photograph the retina after the injection of a specialized fluorescent dye into the patient’s vein. It helps to visualize the retinal blood vessels and interpret whether its functioning is normal.