The lesion may occur within the choroid, between Bruchs membrane and retinal pigment epithelium, or between the retinal pigment epithelium and photoreceptors. Despite the differences in location, the white dots all are of similar composition. The center of the lesion consists of macrophages and epithelioid cells. CD4+ T cells are on the periphery of the granuloma. Benezra has theorized that a large amount of CD8+ T suppressor cells are observed in the later stages of the disease in order to down regulate the inflammatory immune reaction.The formation of a granuloma occurs when activated antigen presenting cells, specifically dendritic cells, "bind to T cells and induce…the release of pro-inflammatory cytokines and chemokines." This response attracts additional antigen presenting cells and will eventually become a granuloma. Choroidal dendritic cells span several levels within the choroid and also associate with the retinal pigment epithelium. Usually, the dendritic cells disappear after removing the antigen. If removal did not occur, the formation of a granuloma would result. The white color of the dots when illuminated may be due to the granulomas composed only of "white cells". Each granuloma will disappear leaving no trace of its presence but in some cases it may leave a punched out scar. It is important to note that the formation of white dots may occur more frequently but is undetected. In normal cases, inflammation of the retina or choroid does not occur.
This is supported by the difficulty in detecting "retinal autoantibodies" in patients with acute zonal occult outer retinopathy.Two other diseases which also present with white dots on the fundus are retinitis punctata albescens and fundus albipunctatus. These diseases are not white dot syndromes, but have much more defined etiology. Retinitis punctata albescens is caused by mutations in RLBP1, the gene for retinaldehyde binding protein 1. In comparison, fundus albipunctatus is caused by mutations in RDH5 gene for an 11-cis-RDH in retinal pigment epithelium cells. See also
Ophthalmology
Retina
Retinal pigment epithelium

References
External links
PIC Society, a UK based support group and discussion forum for people with a diagnosis of punctate inner choroidopathy
Birdshot Uveitis Society, a UK based support group and discussion forum for people with a diagnosis of birdshot chorioretinopathy