Differential diagnosis is mandatory for parafoveal telangiectasias, other forms of choroidal neovascularization and polypoidal choroidal vasculopathy.
Idiopathic parafoveal telangiectasia is a condition involving dilation of retinal capillaries located near the fovea, in one or both eyes.
RPE hyperplasia may also occur, with refractive punctiform deposits and macular leakage being observed in FA.
Migration of one or more venules to the deep retina may also be observed(5).
Anastomoses between retinal vessels and the choroidal circulation have been described, as well as new choroidal vessels.
The most significant differences are the fact that telangiectasias are not associated with serous PED, the RPE is healthier and choroidal neovascularization associated with parafoveal telangiectasias occurs less frequently(5,10).
Differential diagnosis should also be performed for other forms of choroidal neovascularization (CNV) with ICG hot spots (occult CNV) and polypoidal choroidal vasculopathy (PCV).
Small intraretinal haemorrhages, sometimes punctiform, in patients with soft drusen, are very typical in RAP, as are telangiectasias and retino-retinal anastomoses.
Retinal haemorrhages in PCV are normally larger, with round reddish-orange macular lesions being observed in the eye fundus.
OCT is also a useful differential diagnosis tool in RAP, PCV and occult membranes.
In RAP, intraretinal hyperreflectivity may be observed, corresponding to angiomatous proliferation associated with intraretinal fluid and/or RPE detachment.
In PCV, polyps appear in OCT as abrupt protrusions from the REP/Bruch’s membrane band, often associated with neurosensory detachment.