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Spectral-domain OCT helpful in assessing stages of central serous chorioretinopathy
Study enables clinicians to estimate chronicity and recurrence of CSC at time of first examination and to determine proper treatment.
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Volume scans gleaned from spectral-domain optical coherence tomography may allow clinicians to evaluate the chronicity and recurrence of idiopathic central serous chorioretinopathy, according to a retrospective cross-sectional case series.
Patients were classified into five categories of central serous chorioretinopathy (CSC) according to chronicity and recurrence: acute, early chronic, late chronic, recurrent or CSC sequelae. The researchers then surmised the relationship among the five classifications, as well as detailed morphologic changes of the retinal pigment epithelium (RPE) and outer retina, from spectral-domain OCT (SD-OCT) images.
“When evaluating CSC, determination of the chronicity of the disease is important, both for treatment choice and for predicting prognosis,” study co-author Byung Ro Lee, MD, PhD, told Ocular Surgery News. “Acute CSC is usually self-limited, while chronic CSC may cause severe visual loss if not treated actively. However, to date, there has been no appropriate objective method to estimate the chronicity of CSC other than the subjective recall of the patient.”
Byung Ro Lee
The study was published in the American Journal of Ophthalmology.
SD-OCT findings
The researchers found several characteristic SD-OCT findings at specific stages of CSC. For example, large serous retinal detachment was more common in acute CSC, whereas small serous retinal detachment with low to flat pigment epithelial detachments were frequent in late chronic CSC. In addition, retinal dragging with fibrin was more likely detected in the early stage of CSC.
The two SD-OCT characteristics for distinguishing between acute and chronic CSC are thickness of the detached retina and presence of hyperreflective dots, Lee said.
“In an acute case, the detached retina is smoothly thickened, whereas in a chronic case it is smoothly thinned,” he said.
Hyperreflective dots are not present in acute cases but are present in a detached retina in either early or late chronic CSC, Lee said.
The study’s novel finding, that focal RPE proliferation is an RPE alteration associated with CSC, results from the reactive healing process to restore the focal RPE defect, according to Lee.
“This could be an evidence-supporting theory that the focal RPE defect is an initial event of CSC development,” he said.
It may also be possible to infer the natural morphologic progression of CSC from the study.
“Very acutely, fluid from the hyperpermeable choroid enters into the subretina via a focal break of a pigment epithelial detachment,” Lee said. “Retinal dragging toward the [pigment epithelial detachment] may appear and exist until complete detachment. The posterior surface of the detached retina becomes thicker but smooth.”
Likewise, early in chronic cases, the posterior surface becomes granulated or thinned, partially due to focal shedding or disorganization, and is accompanied by hyperreflective dots, Lee said. Conversely, in late chronic cases, the retinal detachment becomes shallow, and the pigment epithelial detachment becomes flat as a restoration.
“The detached retina becomes thinner and more disorganized,” Lee said.
A chronic sustained case eventually results in fovea thinning with RPE atrophy as sequelae of CSC.
Using the images
The findings of the study enabled Lee and colleagues to estimate the duration and recurrence of CSC at the time of the patient’s first examination and to determine the proper treatment modality.
“Moreover, the reference images allow us to differentiate CSC from any kind of macular choroidal neovascularization,” Lee said.
Commercial SD-OCT devices, which provide high-resolution B-scan images, have simple viewer software for quick scrolling of complete scan images, Lee said.
“Therefore, we can instantly do a detailed investigation of RPE and outer retina alterations in CSC and even correlate them with the findings of angiography,” he said.
Lee and colleagues are conducting a follow-up longitudinal study of CSC patients. A separate study of fundus autofluorescence patterns in CSC based on chronicity is under review for publication. – by Bob Kronemyer