UAIM is a rare macular disease described by Yannuzzi et al. on 1991. They reported on nine young patients with unilateral profound visual loss, macular serous detachment and a central scotoma on Amsler chart testing. The same group and others expanded the clinical spectrum on the disease adding the presence of papillitis and bilaterality. The natural course was a rapid, spontaneous improvement in most patients, occurring from weeks to months [1, 2].
We report on a young patient with similar characteristics of those reported by Yannuzzi et al. but lacking the prodromal illness, a much better visual acuity and without the serous detachment.
The good VA of our patient was due to the very early stage of the disease, to the absence of serous macular detachment and to the slight eccentricity of the RPE lesion (Fig. 1a). FFA showed a hypofluorescent lesion on the early phases that became hyperfluorescent in the late recirculation times (Fig. 2b–d). We interpreted the hypofluorescence as the result of RPE oedema and the late hyperfluorescence as the breakdown of the outer blood–retinal barrier, in keeping with an active inflammatory lesion at RPE level [1]. OCT revealed either a thin layer of hyper-reflective material or oedematous RPE protruding into the inner–outer segment junction (Fig. 2d), as reported by others [3, 4].
OCT retinal thickness overlying the lesion at presentation was 305 microns, coming down to 273 microns at 3 months as the inflammation subsided. These could well be that the hyper-reflective material has been reabsorbed or the RPE oedema had settled, leaving an area of RPE derangement with pigment migration into the inner retina causing hyporeflective streaks in the choroid. There was some improvement of the IS/0S junction, corresponding with the improved vision and microperimetry (Fig. 2f). Microperimetry reflected the presence of a scotoma with deep loss of retinal sensitivity overlying the lesion (0 dB) with reduction of retinal sensitivity beyond the lesion margins (Fig. 2a) with a total recovery of sensitivity (20 dB) at 3 months (Fig. 2c), finding not previously reported. Recently, Lam et al. reported on a transient reduction of EOG amplitude in the acute stage of a patient with UAIM, suggesting a more widespread dysfunction of the RPE, in agreement with our microperimetry findings [5].