**3.4 Idiopathic multifocal choroiditis (MFC)/punctate inner choroidopathy (PIC)**

MFC is a chronic and recurrent bilateral inflammatory disease that predominantly affects healthy myopic White women in their third to fifth decade of life with no known associated systemic or ocular diseases [9, 33]. It was first called multifocal uveitis and panuveitis [34], although the panuveitis finding in most cases is absent or rarely seen with minimal vitreous or anterior inflammation. Therefore, a group of experts merged different sub-entities that have been described separately in the past, such as PIC, pseudo-POHS (presumed ocular histoplasmosis syndrome) in

### **Figure 4.**

*This patient has an initial presentation as APMPPE/AMIC in the right eye and as SC in the left eye, but then the lesions were extending and affecting both the posterior pole and the mid-periphery leaving chorioretinal atrophy (a) seen as hypoautofluorescence on fundus autofluorescence (FAF). (b) APMPPE/AMIC: Acute posterior multifocal placoid pigment epitheliopathy (APMPPE)/acute multifocal ischemic choriocapillaritis; SC: Serpiginous choroiditis.*

## **Figure 5.**

*Atrophic chorioretinal lesions. (a) Optical coherence tomography (OCT) shows sub-RPE hyperreflective lesions with overlying outer retina disruption and thinning of choroid. There is also disruption of RPE/Bruch complex with hyperreflectivity beneath. (b) RPE: Retinal pigment epithelium.*

non-endemic areas, progressive subretinal fibrosis, and others, with the single term of idiopathic multifocal choroiditis, regarding them as the same disease [35]. Symptoms include photopsias, blurred vision, and scotomas.

**Figure 6.** *Schlaegel lines.*

Fundus photography shows numerous randomly distributed yellow-white chorioretinal lesions that leave atrophic scars with variable degree of pigmentation in the posterior pole around the disk and/or the mid-periphery (**Figure 5**) that may cluster forming curvilinear chorioretinal streaks (Schlaegel lines) (**Figure 6**) [33]. In as much as one third of cases, there may be seen CNV due to repeated ischemic attacks, which is more frequent than in other primary choriocapillaritis.

FFA identifies recurrences or acute lesions, even in the absence of clinical scars, as early hypofluorescence [9, 36], although early hyperfluorescence can also occur [37–39], and late hyperfluorescence by retinal and subretinal leakage and/or staining due to severe hypoperfusion of the choriocapillaris causing ischemia of outer retina as for APMPPE/AMIC [3, 40]. Early hyperfluorescence with late leakage may represent CNV. Atrophic scars show early hyperfluorescence due to atrophy of the RPE and outer retina (window defect) [9] and areas of hypofluorescence by blockage (masking effect) from pigment deposition (**Figure 7**) [40].

ICGA demonstrates hypofluorescence in new lesions reflecting choriocapillaris hypo or non-perfusion, sometimes in the absence of clinical signs or changes on FFA and helps in detecting progression or regression following inflammation suppressive treatment. Old scarred chorioretinal lesions appear hypofluorescent in all phases [40].

## **Figure 7.** *Atrophic chorioretinal lesions (a) with mixed hype/hypoautofluorescence on fundus autofluorescence (FAF) (b).*

## *Multimodal Imaging of White Dot Syndromes DOI: http://dx.doi.org/10.5772/intechopen.106467*

OCT-A identifies reduced flow in the choriocapillaris co-localizing with FFA and ICGA findings but less extensive, and it is also useful to identify CNV [9, 40, 41]. OCT shows drusen-like sub-RPE material corresponding to fibrosis with overlying outer retinal disruption and choroidal hyperreflectivity beneath them (**Figure 5**). Chorioretinal atrophic areas can also be seen [9, 40].

FAF shows hyperautofluorescence (exposure of RPE lipofuscin due to loss of outer segments of photoreceptors) and hypoautofluorescence by blockage in cicatricial areas [9, 40].

## **3.5 Multiple evanescent white dot syndrome**

MEWDS is an idiopathic and unilateral inflammatory disorder first described by Lee Jampol et al. in 1984 [42] with a predilection for women in their second to fourth decade of life [27]. As the name indicates, it is self-limited, resolving within 8–10 weeks without sequelae and no need for treatment [43].

Flu-like symptoms may precede ocular manifestations in about half of cases, and there is also association with influenza and other vaccinations [3, 44]. Patients refer sudden visual loss, photopsias, dyscromatopsia, and scotomas.

Fundus photography depicts yellowish-white deep chorioretinal lesions, commonly located at the posterior pole and extending to mid-periphery (**Figure 8**). Foveal granularity is seen, and mild intraocular inflammation can be present in the form of vitritis and/or optic disk edema.

FAF shows hyperautofluorescence produced by exposure of RPE due to loss of outer segments photoreceptors/ellipsoid zone and co-localize with ICGA findings (**Figure 8**). A particular finding of MEWDs is the presence of foveal granularity seen as irregular hyperautofluorescence in near-infrared FAF that remains a little longer than other imaging modalities or clinically [45].

ICGA shows early- to mid-phase hypofluorescence [44] better seen in the late phase due to lesions in the ellipsoid zone causing thickening of RPE resulting in abnormal indocyanine green uptake by the RPE [9] or by choriocapillaris nonperfusion of end-capillary portions [3] which can explain both the self-limited

## **Figure 8.**

*Yellowish-white chorioretinal lesions that later resolved. (a) On acute lesions, FFA shows early hyperfluorescence than persists in late phases and a mild hot disk (b).*

damage and the reversibility of the disease in contrast to other primary choriocapillaritis [4, 26].

OCT shows loss of EZ zone which corresponds to FAF and ICGA lesions, and accumulation of hyperreflective material over RPE that may extend anteriorly through the interdigitation zone, EZ, and outer nuclear layer (ONL) [27, 45].

OCTA does not typically detect areas of flow deficit in the choriocapillaris [41, 46] unless severe damage has occurred showing discrete areas of dropout [47, 48]. Nevertheless, OCTA is probably unable to show end-capillary circulation in contrast to larger vessels such as in APMPPE/AMIC, MFC, and SC [26] and needs sufficient flow to identify the presence or absence of vessels, in contrast to ICGA [3, 49].

FFA shows early faint hyperfluorescence (**Figure 8**) that persists in late phases in wreath-like configuration [44] probably due to lesions involving the EZ/RPE or by outer retinal ischemia that in comparison to APMPPE/AMIC is less pronounced because smaller vessels are affected [3, 26]. Less frequently, optic disk hyperfluorescence and focal retinal vascular stain can be seen [44, 50, 51].

Therefore, there is an ongoing debate about pathophysiology of this disorder whether it is a primary phtoreceptoritis [46] or a primary choriochapillaritis leading to secondary ischemic damage at the outer retina and RPE [49], and more studies are needed.
