Optical Density of Subretinal Fluid in Retinal Detachment.

PURPOSE: To investigate the changes over time in optical density (OD) characteristics of subretinal fluid (SRF) in rhegmatogenous retinal detachment (RRD) and their clinical relevance. METHODS: The study included patients with first-onset RRD and no history of intraocular illness who underwent optical coherence tomography (OCT) and whose OCT scans showed sufficient SRF for sampling (08/2013-09/2014). The highest quality B-scan (as graded by the OCT image acquisition software) containing SRF was analyzed. Optical density measurements were obtained using ImageJ. Optical density ratios (ODRs) were calculated as SRF OD divided by vitreous OD. Time from onset of RRD was determined by first signs of visual loss as described in the patient's anamnesis. Patients were divided into three groups by RRD duration: acute (≤1 week), subacute (between 1 week and 1 month), and chronic (>1 month). RESULTS: Thirty-five eyes (34 patients) met the inclusion criteria. The ODR measurement was significantly associated with RRD duration. The ODR had a significant (P < 0.0001) association with the 3-month postoperative visual acuity (VA). Vitreous OD did not differ significantly between the three groups. CONCLUSIONS: The increase over time in the ODR of the SRF in RRD might reflect a change in SRF composition and state of the retina. This, together with a significant association between preoperative ODR values and postoperative VA suggest its potential as a biological prognostic marker.

Three-dimensional configuration of subretinal fluid in central serous chorioretinopathy.

PURPOSE: The purpose of this study was to characterize the 3-dimensional (3D) configuration of subretinal fluid (SRF) in idiopathic central serous chorioretinopathy (CSC) using spectral-domain optical coherence tomography (SDOCT). METHODS: The OCT images of patients with CSC were reviewed retrospectively. The 3D configurations of SRF were assessed using a modified segmentation algorithm of SDOCT. The differences of the configurations between acute and chronic CSC were compared. For the patients with acute CSC, we investigated a possible relationship between early change in 3D configuration and disease prognosis. RESULTS: We included 69 eyes of 68 patients in this study. The mean volume, the greatest basal diameter (GBD), and the area of SRF were not different between acute and chronic CSC. The mean peak height (PH) of SRF and the ratio of PH to GBD in acute CSC (298.13 ± 92.67 µm, 9.44 ± 2.57%) were significantly greater than those in chronic CSC (192.97 ± 71.05 µm, 5.97 ± 1.90%; P < 0.001, P < 0.001, respectively). In patients with acute CSC, the early changing pattern of 3D configurations was significantly different according to the SRF prognosis (P = 0.003). In situ decrease of SRF was observed in 94.7% of the spontaneously resolving group. However, downward elongation of SRF was observed more frequently in the persistent group (58.3%) than in the spontaneously resolving group (6.3%). CONCLUSIONS: The 3D configurations of SRF were different between acute and chronic CSC. In patients with acute onset, the early change of 3D configuration was different and varied according to the SRF prognosis.

Correlation between reflectivity of subretinal fluid in OCT images and concentration of intravitreal VEGF in eyes with diabetic macular edema.

PURPOSE: The reflectivity of optical coherence tomographic (OCT) images has been used to evaluate retinal diseases. The purpose of our study was to determine whether a significant correlation exists between the reflectivity of the subretinal fluid (SRF) and the concentration of intravitreal cytokines in eyes with diabetic macular edema (DME). METHODS: A retrospective comparative study was done of eyes with DME with SRF before vitrectomy. The reflectivity of the SRF was determined from the OCT images. Vitreous samples were collected during vitrectomy, and analyzed for the concentrations of VEGF, IL-6, and IL-8. To determine the factors in the SRF that could affect the reflectivity, the aqueous humor of isolated swine eyes was replaced by saline with plasma, albumin, or fibrinogen, and the reflectivity of the anterior chamber was determined by anterior segment OCT. RESULTS: The average OCT reflectivity of the SRF was 3.52 arbitrary units (AU; 15 eyes; range, 0.01-20.7 AU). The average concentration of VEGF was 870.1 pg/mL, that of IL-6 was 131.7 pg/mL, and that of IL-8 was 224.1 pg/mL. The degree of OCT reflectivity was correlated significantly with the intravitreal VEGF concentration (r = 0.516, P = 0.049, Spearman's rank correlation coefficient), but not with IL-6 or IL-8. In the swine eyes, the presence of plasma, bilirubin, and fibrinogen in the anterior chamber led to significant increases in the reflectivity. CONCLUSIONS: The significant correlation between the reflectivity of SRF and intravitreal VEGF indicates that OCT can be used to monitor the level of VEGF in eyes with DME.

Persistent subretinal fluid after surgery for rhegmatogenous retinal detachment: hypothesis and review.

BACKGROUND: Persistent subretinal fluid after rhegmatogenous retinal detachment (RRD) surgery is responsible for delayed recovery, and may affect the final visual outcome. Cause, consequences, and treatment remain elusive. DESIGN: Literature review and case series. METHODS: We reviewed the pathophysiological principles and therapeutic options from the literature, and we report the results from a subretinal fluid cytology study. Nine eyes from nine patients with macula-involving RRD underwent surgical repair. The cellular content of subretinal fluid (SRF) was studied by electron microscopy and anti-rhodopsin immunostaining. All eyes were assessed postoperatively with optical coherence tomography for the detection of persistent submacular fluid (PSF) (Ethics Committee Ghent University Hospital, registration number B6702006169). RESULTS: Certain patient characteristics as well as surgical methods were implicated. PSF appears to occur more frequently in patients with longstanding detachments treated with buckling surgery. Several therapeutic options have been suggested but safety and efficacy remain unclear. We found PSF in three eyes on postoperative OCT scans, which corresponded to the three cell-rich subretinal samples. CONCLUSIONS: PSF after successful RRD repair seems to be related to fluid composition. We hypothesize, in the absence of an effective treatment, that a modified surgical drainage, including a washout of the subretinal space, could evacuate the subretinal fluid more completely, and may prevent this complication.

Autofluorescence of the cells in human subretinal fluid.

PURPOSE: The origin of autofluorescence in the subretinal space and the autofluorescence properties of the cells were investigated in surgically collected subretinal fluid. METHODS: Subretinal fluid was surgically collected from four eyes of patients with rhegmatogenous retinal detachment (three eyes) and Coats' disease (one eye). After cytocentrifuge preparation of the cells in the fluid and immunofluorescence staining, a cytologic examination was conducted by using confocal scanning laser microscopy. The autofluorescence of the cells was elucidated by measuring the fluorescence spectra with spectroscopy, to obtain different excitation laser light emission fingerprints. RESULTS: The cells from the subretinal fluid were classified into three types: CD68-negative cells containing numerous pigmented granules, CD68-positive cells containing few pigments, and CD68-negative cells with no pigmented granules. Autofluorescence was observed in the inclusions of the cells classified into the former two types. When the cells were excited by a 458- or 488-nm laser light, emission spectra in autofluorescence showed little difference between CD68-positive and -negative cells. Peak analysis confirmed that the two types of cells showed the same emission peaks within this range of excitation light. CONCLUSIONS: Autofluorescent inclusions appeared in the CD68-positive and -negative cells in the subretinal fluid. The macrophages in the subretinal fluid possess autofluorescence that is spectroscopically similar to lipofuscin. Autofluorescence of macrophages can be attributed to degenerated outer segments and debris from apoptotic photoreceptors. Clinicians should consider migration of macrophages, in addition to retinal pigment epithelium, as the possible source when abnormal fundus autofluorescence is observed using an ordinary set of fluorescence filters.