**3.12 Dipping sign**

It is a pathologic retinal sign that may be appreciated with high-resolution OCT images in some patients with acute CSCR. It is characterized by getting an inverted triangle shape at the outer surface of the detached retina, in those eyes with fibrinous exudate in the subretinal space that protrudes over the RPE [3]. The primary cause of dipping sign seems to be traction due to the fibrinous exudates and the swelling of

**77**

*New Landmarks, Signs, and Findings in Optical Coherence Tomography*

the ONL. It has been reported that some of the leakage sites (20.3%) show fibrinous exudate as a highly reflective area in the subretinal space, around the leakage site [84]. Additional observations with SD-OCT include thickening of the outer photoreceptor segment layer with invisibility of the inner segment-outer segment junction line and "dipping" of the posterior retinal layer toward the RPE [84, 85]. In later stages, granular deposits may become visible at the posterior surface of the detached retina [85]. It has been documented a decrease in foveal thickness once CSCR is resolved.

CDF is a rare form of macular pathology that can be precisely diagnosed only with OCT. It is characterized by large cystic spaces, or in some cases, giant single cyst in the fovea. It can occur with or without thinned septa between cystic spaces. Usually, it affects patients with diabetic maculopathy, uveitis, RVO, AMD, associated with Streptococcus constellatus endocarditis, and CSR [3, 86]. The hyperreflective OCT appearance of these lesions, followed by cystic change and permanent visual loss, suggests that they might represent retinal infarctions. Their predilection for the fovea may reflect the high metabolic demand at this area of the retina and

This pathology is associated with a distortion of IS/OS layer and loss of outer segment of photoreceptors. In comparison with CME, CDF has a more extensive and multitude cysts. As opposed to CME, although CDF cysts may shrink or disappear, there is a limited improvement in visual acuity [3]. FA and fundus autofluores-

Thanks to Antonio Arias Palomero and José Juan Valdés González for the effort

Dr. Ascaso reports nonfinancial support from Topcon and Zeiss. All remaining authors have declared no conflicts of interest. All coauthors have seen and agreed

*DOI: http://dx.doi.org/10.5772/intechopen.84242*

**3.13 Cystoid foveal degeneration (CDF)**

**Acknowledgements**

**Conflicts of interest**

with the contents of the manuscript.

the narrow-bore capillaries of the perifoveal vasculature.

of searching some of the images showed in this chapter.

cence (FAF) are not capable of distinguishing CME from CDF.

*New Landmarks, Signs, and Findings in Optical Coherence Tomography DOI: http://dx.doi.org/10.5772/intechopen.84242*

the ONL. It has been reported that some of the leakage sites (20.3%) show fibrinous exudate as a highly reflective area in the subretinal space, around the leakage site [84]. Additional observations with SD-OCT include thickening of the outer photoreceptor segment layer with invisibility of the inner segment-outer segment junction line and "dipping" of the posterior retinal layer toward the RPE [84, 85]. In later stages, granular deposits may become visible at the posterior surface of the detached retina [85]. It has been documented a decrease in foveal thickness once CSCR is resolved.

## **3.13 Cystoid foveal degeneration (CDF)**

*A Practical Guide to Clinical Application of OCT in Ophthalmology*

**76**

artery [81, 83].

**3.12 Dipping sign**

**3.11 Choroidal macrovessel**

**Figure 12.**

It is a rare ocular lesion which appears on fundus examination as an abnormal, tortuous vessel deep to the retina. It was first described as a serpiginoid atrophic lesion in the temporal macula, with an orange-red aspect and several unspecific choroidal spots in the posterior pole [81]. Choroidal macrovessel is not associated with acute inflammation and symptoms. Some reports have shown hyperpigmentation of the RPE, debris in the subretinal space, and changes in the outer nuclear layer (ONL) thickness [82, 83]. SD-OCT reveals a tubular structure which shows hyperreflectivity band below RPE representing the superior edge of the lesion, with an elevation of RPE and photoreceptor and posterior shadowing [81]. In recent studies, it has been explored with enhanced-depth imaging spectral domain optical coherence tomography (EDI SD-OCT) showing a vascular structure that traversed the entire choroidal thickness and produces an indentation at the choroidal-scleral junction and the ellipsoid zone (EZ) causing a reduction of the ONL thickness [82, 83]. A differential diagnosis from choroidal macrovessel should be made with subretinal nematode tract, choroidal hemangioma, inflammatory choroidopathy, retinochoroidal anastomosis, vortex varix, and aberrant long posterior ciliary

*Subretinal retention of perfluorocarbon liquid (PFCL) after retinal detachment surgery.*

It is a pathologic retinal sign that may be appreciated with high-resolution OCT images in some patients with acute CSCR. It is characterized by getting an inverted triangle shape at the outer surface of the detached retina, in those eyes with fibrinous exudate in the subretinal space that protrudes over the RPE [3]. The primary cause of dipping sign seems to be traction due to the fibrinous exudates and the swelling of

CDF is a rare form of macular pathology that can be precisely diagnosed only with OCT. It is characterized by large cystic spaces, or in some cases, giant single cyst in the fovea. It can occur with or without thinned septa between cystic spaces. Usually, it affects patients with diabetic maculopathy, uveitis, RVO, AMD, associated with Streptococcus constellatus endocarditis, and CSR [3, 86]. The hyperreflective OCT appearance of these lesions, followed by cystic change and permanent visual loss, suggests that they might represent retinal infarctions. Their predilection for the fovea may reflect the high metabolic demand at this area of the retina and the narrow-bore capillaries of the perifoveal vasculature.

This pathology is associated with a distortion of IS/OS layer and loss of outer segment of photoreceptors. In comparison with CME, CDF has a more extensive and multitude cysts. As opposed to CME, although CDF cysts may shrink or disappear, there is a limited improvement in visual acuity [3]. FA and fundus autofluorescence (FAF) are not capable of distinguishing CME from CDF.

#### **Acknowledgements**

Thanks to Antonio Arias Palomero and José Juan Valdés González for the effort of searching some of the images showed in this chapter.

### **Conflicts of interest**

Dr. Ascaso reports nonfinancial support from Topcon and Zeiss. All remaining authors have declared no conflicts of interest. All coauthors have seen and agreed with the contents of the manuscript.
