Five types of macular change that have been previously designated as "macular edema" are described. In typical cases, each of these lesions is different from the others. In some patients, more than one type of change may involve the macula. Also, some of these conditions appear to be more closely related to one another than do others. The lesions in categories 1 and 2 may each be a variant of the same basic process. Likewise, the changes classed as categories 4 and 5 may in some instances be stages in the evolution of the same disease. Slit-lamp examination of the fundus with a Hruby lens or Goldmann lens and the use of intravenous fluorescein are of great value in the differential diagnosis of these lesions.
Maumenee AE. Further Advances in the Study of the Macula. Arch Ophthalmol. 1967;78(2):151-165. doi:10.1001/archopht.1967.00980030153008