Fig. 4.29 Fundus photograph, posterior scleritis. Note the detachment of the pigment epithelium supranasal to the fovea, as well as the retinal striae

Fig. 4.30 Fluorescein angiogram of the same patient as in Fig. 4.29. Note the ßuorescein accumulation in the area of pigment epithelial detachment

which are important Þndings for the differential diagnosis of posterior scleritis with orbital inßammatory diseases and orbital tumors [102Ð104].

Radioactive Phosphorus (32P) Uptake

The 32P uptake test is of little value in differentiating posterior scleritis from choroidal tumors because the test may be positive or negative in posterior scleritis [94, 105Ð107]. The 32P uptake test also may be positive in a variety of inßammatory, vascular, hemorrhagic, and osseous conditions of the posterior segment [105].

Fluorescein Angiography

Fluorescein angiography may reveal retinal pigment epithelial detachment (Figs. 4.29 and 4.30), serous retinal detachment, disk edema, or cystoid macular edema. In cases with serous retinal detachment, subretinal ßuid shows diffuse choroidal mottling in the early phases, numerous pinpoint spots of hyperßuorescence in the middle phases, and intense staining of the subretinal ßuid in the late phases [84]. Choroidal folds are seen as alternating hyperßuorescent and hypoßuorescent streaks (Fig. 4.31) [108]. The ßuorescein pattern conÞrms their presence in case of clinical doubt. The folds are recognized by the early passage of ßuorescein through the choroid, persisting through the late venous phase without leakage. The light portion of the fold corresponds to the crest and transmits the choroidal

Fig. 4.31 Fluorescein angiogram: posterior scleritis. Note the choroidal and retinal striae as well as the retinal pigment epithelial window defects

ßuorescence, whereas the dark portion of the fold corresponds to the valley and does not transmit the choroidal ßuorescence. Inclination and subsequent thickness of the retinal pigment epithelium in the valleys and atrophy of the retinal pigment epithelium in the crests may be a possible explanation for the hypoßuorescent and hyperßuorescent areas, respectively [95, 108, 109]. Retinal striae are not seen on ßuorescein angiography; this helps to differentiate them from choroidal folds [95]. Because all these Þndings may also be seen in many other choroidal, retinal, and orbital conditions, ßuorescein